├── code ├── 2 ├── .dir-locals.el ├── fcntl.h ├── types.h ├── date.h ├── show1 ├── BUGS ├── .gitignore ├── .cvsignore ├── echo.c ├── zombie.c ├── toc.hdr ├── kill.c ├── sleeplock.h ├── spinp ├── ln.c ├── stat.h ├── spinlock.h ├── buf.h ├── rm.c ├── printpcs ├── mkdir.c ├── date.c ├── sign.pl ├── alarmtest.c ├── picirq.c ├── toc.ftr ├── initcode.S ├── syscall.h ├── usys.S ├── trapasm.S ├── memlayout.h ├── pr.pl ├── cat.c ├── .gdbinit.tmpl ├── init.c ├── swtch.S ├── param.h ├── elf.h ├── file.h ├── runoff.list ├── asm.h ├── forktest.c ├── sleeplock.c ├── wc.c ├── uthread_switch.S ├── user.h ├── cuth ├── kbd.c ├── vectors.pl ├── big.c ├── stressfs.c ├── LICENSE ├── memide.c ├── uart.c ├── traps.h ├── ulib.c ├── printf.c ├── kernel.ld ├── ls.c ├── string.c ├── umalloc.c ├── fs.h ├── entry.S ├── sysproc.c ├── ioapic.c ├── mp.h ├── grep.c ├── kalloc.c ├── proc.h ├── bootmain.c ├── sleep1.p ├── runoff1 ├── pipe.c ├── runoff.spec ├── entryother.S ├── exec.c ├── bootasm.S ├── uthread.c ├── spinlock.c ├── file.c ├── main.c ├── mp.c ├── trap.c ├── kbd.h ├── bio.c ├── syscall.c ├── x86.h ├── ide.c ├── symlink.patch ├── Notes ├── TRICKS ├── runoff ├── defs.h ├── log.c ├── console.c ├── gdbutil ├── lapic.c ├── mkfs.c ├── Makefile └── sysfile.c └── README.md /code/.dir-locals.el: -------------------------------------------------------------------------------- 1 | ((c-mode 2 | (indent-tabs-mode . nil) 3 | (c-file-style . "bsd") 4 | (c-basic-offset . 2))) 5 | -------------------------------------------------------------------------------- /code/fcntl.h: -------------------------------------------------------------------------------- 1 | #define O_RDONLY 0x000 2 | #define O_WRONLY 0x001 3 | #define O_RDWR 0x002 4 | #define O_CREATE 0x200 5 | -------------------------------------------------------------------------------- /code/types.h: -------------------------------------------------------------------------------- 1 | typedef unsigned int uint; 2 | typedef unsigned short ushort; 3 | typedef unsigned char uchar; 4 | typedef uint pde_t; 5 | -------------------------------------------------------------------------------- /code/date.h: -------------------------------------------------------------------------------- 1 | struct rtcdate { 2 | uint second; 3 | uint minute; 4 | uint hour; 5 | uint day; 6 | uint month; 7 | uint year; 8 | }; 9 | -------------------------------------------------------------------------------- /code/show1: -------------------------------------------------------------------------------- 1 | #!/bin/sh 2 | 3 | runoff1 "$@" | pr.pl -h "xv6/$@" | mpage -m50t50b -o -bLetter -T -t -2 -FLucidaSans-Typewriter83 -L60 >x.ps; gv --swap x.ps 4 | -------------------------------------------------------------------------------- /code/BUGS: -------------------------------------------------------------------------------- 1 | formatting: 2 | need to fix PAGEBREAK mechanism 3 | 4 | sh: 5 | can't always runcmd in child -- breaks cd. 6 | maybe should hard-code PATH=/ ? 7 | 8 | -------------------------------------------------------------------------------- /code/.gitignore: -------------------------------------------------------------------------------- 1 | *~ 2 | _* 3 | *.o 4 | *.d 5 | *.asm 6 | *.sym 7 | *.img 8 | vectors.S 9 | bootblock 10 | entryother 11 | initcode 12 | initcode.out 13 | kernel 14 | kernelmemfs 15 | mkfs 16 | .gdbinit 17 | -------------------------------------------------------------------------------- /code/.cvsignore: -------------------------------------------------------------------------------- 1 | *.asm 2 | *.d 3 | *.sym 4 | _* 5 | kernel 6 | user1 7 | userfs 8 | usertests 9 | xv6.img 10 | vectors.S 11 | bochsout.txt 12 | bootblock 13 | bootother 14 | bootother.out 15 | parport.out 16 | fmt 17 | -------------------------------------------------------------------------------- /code/echo.c: -------------------------------------------------------------------------------- 1 | #include "types.h" 2 | #include "stat.h" 3 | #include "user.h" 4 | 5 | int 6 | main(int argc, char *argv[]) 7 | { 8 | int i; 9 | 10 | for(i = 1; i < argc; i++) 11 | printf(1, "%s%s", argv[i], i+1 < argc ? " " : "\n"); 12 | exit(); 13 | } 14 | -------------------------------------------------------------------------------- /code/zombie.c: -------------------------------------------------------------------------------- 1 | // Create a zombie process that 2 | // must be reparented at exit. 3 | 4 | #include "types.h" 5 | #include "stat.h" 6 | #include "user.h" 7 | 8 | int 9 | main(void) 10 | { 11 | if(fork() > 0) 12 | sleep(5); // Let child exit before parent. 13 | exit(); 14 | } 15 | -------------------------------------------------------------------------------- /code/toc.hdr: -------------------------------------------------------------------------------- 1 | The numbers to the left of the file names in the table are sheet numbers. 2 | The source code has been printed in a double column format with fifty 3 | lines per column, giving one hundred lines per sheet (or page). 4 | Thus there is a convenient relationship between line numbers and sheet numbers. 5 | 6 | 7 | -------------------------------------------------------------------------------- /code/kill.c: -------------------------------------------------------------------------------- 1 | #include "types.h" 2 | #include "stat.h" 3 | #include "user.h" 4 | 5 | int 6 | main(int argc, char **argv) 7 | { 8 | int i; 9 | 10 | if(argc < 2){ 11 | printf(2, "usage: kill pid...\n"); 12 | exit(); 13 | } 14 | for(i=1; i&2 5 | exit 1 6 | fi 7 | 8 | rm -f $1.trail 9 | spin -a $1 || exit 1 10 | cc -DSAFETY -DREACH -DMEMLIM=500 -o pan pan.c 11 | pan -i 12 | rm pan.* pan 13 | if [ -f $1.trail ]; then 14 | spin -t -p $1 15 | fi 16 | 17 | -------------------------------------------------------------------------------- /code/ln.c: -------------------------------------------------------------------------------- 1 | #include "types.h" 2 | #include "stat.h" 3 | #include "user.h" 4 | 5 | int 6 | main(int argc, char *argv[]) 7 | { 8 | if(argc != 3){ 9 | printf(2, "Usage: ln old new\n"); 10 | exit(); 11 | } 12 | if(link(argv[1], argv[2]) < 0) 13 | printf(2, "link %s %s: failed\n", argv[1], argv[2]); 14 | exit(); 15 | } 16 | -------------------------------------------------------------------------------- /code/stat.h: -------------------------------------------------------------------------------- 1 | #define T_DIR 1 // Directory 2 | #define T_FILE 2 // File 3 | #define T_DEV 3 // Device 4 | 5 | struct stat { 6 | short type; // Type of file 7 | int dev; // File system's disk device 8 | uint ino; // Inode number 9 | short nlink; // Number of links to file 10 | uint size; // Size of file in bytes 11 | }; 12 | -------------------------------------------------------------------------------- /code/spinlock.h: -------------------------------------------------------------------------------- 1 | // Mutual exclusion lock. 2 | struct spinlock { 3 | uint locked; // Is the lock held? 4 | 5 | // For debugging: 6 | char *name; // Name of lock. 7 | struct cpu *cpu; // The cpu holding the lock. 8 | uint pcs[10]; // The call stack (an array of program counters) 9 | // that locked the lock. 10 | }; 11 | 12 | -------------------------------------------------------------------------------- /code/buf.h: -------------------------------------------------------------------------------- 1 | struct buf { 2 | int flags; 3 | uint dev; 4 | uint blockno; 5 | struct sleeplock lock; 6 | uint refcnt; //引用次数 7 | struct buf *prev; // LRU cache list 8 | struct buf *next; 9 | struct buf *qnext; // disk queue 10 | uchar data[BSIZE]; 11 | }; 12 | #define B_VALID 0x2 // buffer has been read from disk 13 | #define B_DIRTY 0x4 // buffer needs to be written to disk 14 | 15 | -------------------------------------------------------------------------------- /code/rm.c: -------------------------------------------------------------------------------- 1 | #include "types.h" 2 | #include "stat.h" 3 | #include "user.h" 4 | 5 | int 6 | main(int argc, char *argv[]) 7 | { 8 | int i; 9 | 10 | if(argc < 2){ 11 | printf(2, "Usage: rm files...\n"); 12 | exit(); 13 | } 14 | 15 | for(i = 1; i < argc; i++){ 16 | if(unlink(argv[i]) < 0){ 17 | printf(2, "rm: %s failed to delete\n", argv[i]); 18 | break; 19 | } 20 | } 21 | 22 | exit(); 23 | } 24 | -------------------------------------------------------------------------------- /code/printpcs: -------------------------------------------------------------------------------- 1 | #!/bin/sh 2 | 3 | # Decode the symbols from a panic EIP list 4 | 5 | # Find a working addr2line 6 | for p in i386-jos-elf-addr2line addr2line; do 7 | if which $p 2>&1 >/dev/null && \ 8 | $p -h 2>&1 | grep -q '\belf32-i386\b'; then 9 | break 10 | fi 11 | done 12 | 13 | # Enable as much pretty-printing as this addr2line can do 14 | $p $($p -h | grep ' -[aipsf] ' | awk '{print $1}') -e kernel "$@" 15 | -------------------------------------------------------------------------------- /code/mkdir.c: -------------------------------------------------------------------------------- 1 | #include "types.h" 2 | #include "stat.h" 3 | #include "user.h" 4 | 5 | int 6 | main(int argc, char *argv[]) 7 | { 8 | int i; 9 | 10 | if(argc < 2){ 11 | printf(2, "Usage: mkdir files...\n"); 12 | exit(); 13 | } 14 | 15 | for(i = 1; i < argc; i++){ 16 | if(mkdir(argv[i]) < 0){ 17 | printf(2, "mkdir: %s failed to create\n", argv[i]); 18 | break; 19 | } 20 | } 21 | 22 | exit(); 23 | } 24 | -------------------------------------------------------------------------------- /code/date.c: -------------------------------------------------------------------------------- 1 | #include"types.h" 2 | #include"user.h" 3 | #include"date.h" 4 | int 5 | main(int argc,char *argv[]){ 6 | struct rtcdate r; 7 | if(date(&r)){ 8 | printf(2,"data failed\n"); 9 | exit(); 10 | } 11 | printf(2,"year:%d,month:%d,day:%d,hour:%d,minute:%d,minute:%d,second:%d\n",r.year,r.month,r.day,r.hour,r.minute,r.second); 12 | exit(); 13 | } 14 | int 15 | test(){ 16 | int a=4+6; 17 | return a; 18 | } 19 | -------------------------------------------------------------------------------- /code/sign.pl: -------------------------------------------------------------------------------- 1 | #!/usr/bin/perl 2 | 3 | open(SIG, $ARGV[0]) || die "open $ARGV[0]: $!"; 4 | 5 | $n = sysread(SIG, $buf, 1000); 6 | 7 | if($n > 510){ 8 | print STDERR "boot block too large: $n bytes (max 510)\n"; 9 | exit 1; 10 | } 11 | 12 | print STDERR "boot block is $n bytes (max 510)\n"; 13 | 14 | $buf .= "\0" x (510-$n); 15 | $buf .= "\x55\xAA"; 16 | 17 | open(SIG, ">$ARGV[0]") || die "open >$ARGV[0]: $!"; 18 | print SIG $buf; 19 | close SIG; 20 | -------------------------------------------------------------------------------- /code/alarmtest.c: -------------------------------------------------------------------------------- 1 | #include "types.h" 2 | #include "stat.h" 3 | #include "user.h" 4 | 5 | void periodic(); 6 | 7 | int 8 | main(int argc,char *argv[]){ 9 | int i; 10 | printf(1,"alarmtest starting\n"); 11 | alarm(10,periodic); 12 | write(2,"kexinxin",1); 13 | for (i=0;i<25*5000000;i++){ 14 | if((i%2500000)==0) 15 | write(2,".",1); 16 | } 17 | exit(); 18 | } 19 | void 20 | periodic(){ 21 | printf(1,"alarmTest!\n"); 22 | } 23 | -------------------------------------------------------------------------------- /code/picirq.c: -------------------------------------------------------------------------------- 1 | #include "types.h" 2 | #include "x86.h" 3 | #include "traps.h" 4 | 5 | // I/O Addresses of the two programmable interrupt controllers 6 | #define IO_PIC1 0x20 // Master (IRQs 0-7) 7 | #define IO_PIC2 0xA0 // Slave (IRQs 8-15) 8 | 9 | // Don't use the 8259A interrupt controllers. Xv6 assumes SMP hardware. 10 | void 11 | picinit(void) 12 | { 13 | // mask all interrupts 14 | outb(IO_PIC1+1, 0xFF); 15 | outb(IO_PIC2+1, 0xFF); 16 | } 17 | 18 | //PAGEBREAK! 19 | // Blank page. 20 | -------------------------------------------------------------------------------- /code/toc.ftr: -------------------------------------------------------------------------------- 1 | 2 | 3 | The source listing is preceded by a cross-reference that lists every defined 4 | constant, struct, global variable, and function in xv6. Each entry gives, 5 | on the same line as the name, the line number (or, in a few cases, numbers) 6 | where the name is defined. Successive lines in an entry list the line 7 | numbers where the name is used. For example, this entry: 8 | 9 | swtch 2658 10 | 0374 2428 2466 2657 2658 11 | 12 | indicates that swtch is defined on line 2658 and is mentioned on five lines 13 | on sheets 03, 24, and 26. 14 | -------------------------------------------------------------------------------- /code/initcode.S: -------------------------------------------------------------------------------- 1 | # Initial process execs /init. 2 | # This code runs in user space. 3 | 4 | #include "syscall.h" 5 | #include "traps.h" 6 | 7 | 8 | # exec(init, argv) 9 | .globl start 10 | start: 11 | pushl $argv 12 | pushl $init 13 | pushl $0 // where caller pc would be 14 | movl $SYS_exec, %eax 15 | int $T_SYSCALL 16 | 17 | # for(;;) exit(); 18 | exit: 19 | movl $SYS_exit, %eax 20 | int $T_SYSCALL 21 | jmp exit 22 | 23 | # char init[] = "/init\0"; 24 | init: 25 | .string "/init\0" 26 | 27 | # char *argv[] = { init, 0 }; 28 | .p2align 2 29 | argv: 30 | .long init 31 | .long 0 32 | 33 | -------------------------------------------------------------------------------- /code/syscall.h: -------------------------------------------------------------------------------- 1 | // System call numbers 2 | #define SYS_fork 1 3 | #define SYS_exit 2 4 | #define SYS_wait 3 5 | #define SYS_pipe 4 6 | #define SYS_read 5 7 | #define SYS_kill 6 8 | #define SYS_exec 7 9 | #define SYS_fstat 8 10 | #define SYS_chdir 9 11 | #define SYS_dup 10 12 | #define SYS_getpid 11 13 | #define SYS_sbrk 12 14 | #define SYS_sleep 13 15 | #define SYS_uptime 14 16 | #define SYS_open 15 17 | #define SYS_write 16 18 | #define SYS_mknod 17 19 | #define SYS_unlink 18 20 | #define SYS_link 19 21 | #define SYS_mkdir 20 22 | #define SYS_close 21 23 | #define SYS_date 22 24 | #define SYS_alarm 23 25 | -------------------------------------------------------------------------------- /code/usys.S: -------------------------------------------------------------------------------- 1 | #include "syscall.h" 2 | #include "traps.h" 3 | 4 | #define SYSCALL(name) \ 5 | .globl name; \ 6 | name: \ 7 | movl $SYS_ ## name, %eax; \ 8 | int $T_SYSCALL; \ 9 | ret 10 | 11 | SYSCALL(fork) 12 | SYSCALL(exit) 13 | SYSCALL(wait) 14 | SYSCALL(pipe) 15 | SYSCALL(read) 16 | SYSCALL(write) 17 | SYSCALL(close) 18 | SYSCALL(kill) 19 | SYSCALL(exec) 20 | SYSCALL(open) 21 | SYSCALL(mknod) 22 | SYSCALL(unlink) 23 | SYSCALL(fstat) 24 | SYSCALL(link) 25 | SYSCALL(mkdir) 26 | SYSCALL(chdir) 27 | SYSCALL(dup) 28 | SYSCALL(getpid) 29 | SYSCALL(sbrk) 30 | SYSCALL(sleep) 31 | SYSCALL(uptime) 32 | SYSCALL(date) 33 | SYSCALL(alarm) 34 | -------------------------------------------------------------------------------- /code/trapasm.S: -------------------------------------------------------------------------------- 1 | #include "mmu.h" 2 | 3 | # vectors.S sends all traps here. 4 | .globl alltraps 5 | alltraps: 6 | # Build trap frame. 7 | pushl %ds 8 | pushl %es 9 | pushl %fs 10 | pushl %gs 11 | pushal #其中eax记录了系统调用号 12 | 13 | # Set up data segments. 14 | movw $(SEG_KDATA<<3), %ax 15 | movw %ax, %ds 16 | movw %ax, %es 17 | 18 | # Call trap(tf), where tf=%esp 19 | pushl %esp 20 | call trap 21 | addl $4, %esp #之前将esp压栈作为trap调用的参数，现在需要将它弹出 22 | 23 | # Return falls through to trapret... 24 | .globl trapret 25 | trapret: 26 | popal #eax寄存器被修改了，里面存放的是系统调用的返回值 27 | popl %gs 28 | popl %fs 29 | popl %es 30 | popl %ds 31 | addl $0x8, %esp # trapno and errcode 32 | iret 33 | -------------------------------------------------------------------------------- /code/memlayout.h: -------------------------------------------------------------------------------- 1 | // Memory layout 2 | 3 | #define EXTMEM 0x100000 // Start of extended memory 4 | #define PHYSTOP 0xE000000 // Top physical memory 5 | #define DEVSPACE 0xFE000000 // Other devices are at high addresses 6 | 7 | // Key addresses for address space layout (see kmap in vm.c for layout) 8 | #define KERNBASE 0x80000000 // First kernel virtual address 9 | #define KERNLINK (KERNBASE+EXTMEM) // Address where kernel is linked 10 | 11 | #define V2P(a) (((uint) (a)) - KERNBASE) 12 | #define P2V(a) (((void *) (a)) + KERNBASE) 13 | 14 | #define V2P_WO(x) ((x) - KERNBASE) // same as V2P, but without casts 15 | #define P2V_WO(x) ((x) + KERNBASE) // same as P2V, but without casts 16 | -------------------------------------------------------------------------------- /code/pr.pl: -------------------------------------------------------------------------------- 1 | #!/usr/bin/perl 2 | 3 | use POSIX qw(strftime); 4 | 5 | if($ARGV[0] eq "-h"){ 6 | shift @ARGV; 7 | $h = $ARGV[0]; 8 | shift @ARGV; 9 | }else{ 10 | $h = $ARGV[0]; 11 | } 12 | 13 | $page = 0; 14 | $now = strftime "%b %e %H:%M %Y", localtime; 15 | 16 | @lines = <>; 17 | for($i=0; $i<@lines; $i+=50){ 18 | print "\n\n"; 19 | ++$page; 20 | print "$now $h Page $page\n"; 21 | print "\n\n"; 22 | for($j=$i; $j<@lines && $j<$i +50; $j++){ 23 | $lines[$j] =~ s!//DOC.*!!; 24 | print $lines[$j]; 25 | } 26 | for(; $j<$i+50; $j++){ 27 | print "\n"; 28 | } 29 | $sheet = ""; 30 | if($lines[$i] =~ /^([0-9][0-9])[0-9][0-9] /){ 31 | $sheet = "Sheet $1"; 32 | } 33 | print "\n\n"; 34 | print "$sheet\n"; 35 | print "\n\n"; 36 | } 37 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # xv6OS 2 | 该项目完成了一个小型的操作系统。麻雀虽小五脏俱全，包含了操作系统的内存管理、进程管理、文件系统等部分 3 | 4 | 相关的技术博文如下： 5 | 6 | XV6环境搭建及注意事项 https://www.cnblogs.com/kexinxin/p/9939154.html 7 | 8 | XV6第一个进程 https://www.cnblogs.com/kexinxin/p/9939178.html 9 | 10 | XV6页表 https://www.cnblogs.com/kexinxin/p/9940864.html 11 | 12 | XV6陷入，中断和驱动程序 https://www.cnblogs.com/kexinxin/p/9940859.html 13 | 14 | XV6调度 https://www.cnblogs.com/kexinxin/p/9940855.html 15 | 16 | XV6文件系统 https://www.cnblogs.com/kexinxin/p/9940856.html 17 | 18 | XV6锁 https://www.cnblogs.com/kexinxin/p/9940853.html 19 | 20 | XV6操作系统接口 https://www.cnblogs.com/kexinxin/p/9939159.html 21 | 22 | XV内存变化 https://www.cnblogs.com/kexinxin/p/9939149.html 23 | 24 | XV6上下文切换 https://www.cnblogs.com/kexinxin/p/9939142.html 25 | 26 | -------------------------------------------------------------------------------- /code/cat.c: -------------------------------------------------------------------------------- 1 | #include "types.h" 2 | #include "stat.h" 3 | #include "user.h" 4 | 5 | char buf[512]; 6 | 7 | void 8 | cat(int fd) 9 | { 10 | int n; 11 | 12 | while((n = read(fd, buf, sizeof(buf))) > 0) { 13 | if (write(1, buf, n) != n) { 14 | printf(1, "cat: write error\n"); 15 | exit(); 16 | } 17 | } 18 | if(n < 0){ 19 | printf(1, "cat: read error\n"); 20 | exit(); 21 | } 22 | } 23 | 24 | int 25 | main(int argc, char *argv[]) 26 | { 27 | int fd, i; 28 | 29 | if(argc <= 1){ 30 | cat(0); 31 | exit(); 32 | } 33 | 34 | for(i = 1; i < argc; i++){ 35 | if((fd = open(argv[i], 0)) < 0){ 36 | printf(1, "cat: cannot open %s\n", argv[i]); 37 | exit(); 38 | } 39 | cat(fd); 40 | close(fd); 41 | } 42 | exit(); 43 | } 44 | -------------------------------------------------------------------------------- /code/.gdbinit.tmpl: -------------------------------------------------------------------------------- 1 | set $lastcs = -1 2 | 3 | define hook-stop 4 | # There doesn't seem to be a good way to detect if we're in 16- or 5 | # 32-bit mode, but in 32-bit mode we always run with CS == 8 in the 6 | # kernel and CS == 35 in user space 7 | if $cs == 8 || $cs == 35 8 | if $lastcs != 8 && $lastcs != 35 9 | set architecture i386 10 | end 11 | x/i $pc 12 | else 13 | if $lastcs == -1 || $lastcs == 8 || $lastcs == 35 14 | set architecture i8086 15 | end 16 | # Translate the segment:offset into a physical address 17 | printf "[%4x:%4x] ", $cs, $eip 18 | x/i $cs*16+$eip 19 | end 20 | set $lastcs = $cs 21 | end 22 | 23 | echo + target remote localhost:1234\n 24 | target remote localhost:1234 25 | 26 | echo + symbol-file kernel\n 27 | symbol-file kernel 28 | -------------------------------------------------------------------------------- /code/init.c: -------------------------------------------------------------------------------- 1 | // init: The initial user-level program 2 | 3 | #include "types.h" 4 | #include "stat.h" 5 | #include "user.h" 6 | #include "fcntl.h" 7 | 8 | char *argv[] = { "sh", 0 }; 9 | 10 | int 11 | main(void) 12 | { 13 | int pid, wpid; 14 | 15 | if(open("console", O_RDWR) < 0){ 16 | mknod("console", 1, 1); 17 | open("console", O_RDWR); 18 | } 19 | dup(0); // stdout 20 | dup(0); // stderr 21 | 22 | for(;;){ 23 | printf(1, "init: starting sh\n"); 24 | pid = fork(); 25 | if(pid < 0){ 26 | printf(1, "init: fork failed\n"); 27 | exit(); 28 | } 29 | if(pid == 0){ 30 | exec("sh", argv); 31 | printf(1, "init: exec sh failed\n"); 32 | exit(); 33 | } 34 | while((wpid=wait()) >= 0 && wpid != pid) 35 | printf(1, "zombie!\n"); 36 | } 37 | } 38 | -------------------------------------------------------------------------------- /code/swtch.S: -------------------------------------------------------------------------------- 1 | # Context switch 2 | # 3 | # void swtch(struct context **old, struct context *new); 4 | # 5 | # Save the current registers on the stack, creating 6 | # a struct context, and save its address in *old. 7 | # Switch stacks to new and pop previously-saved registers. 8 | 9 | .globl swtch 10 | swtch: 11 | movl 4(%esp), %eax #把old放到eax中 12 | movl 8(%esp), %edx #把new放到edx中 13 | 14 | #已经隐式的保存eip,函数调用时压入 15 | # Save old callee-save registers 16 | pushl %ebp 17 | pushl %ebx 18 | pushl %esi 19 | pushl %edi 20 | #此时栈结构就是一个'struct context' 21 | 22 | # Switch stacks 23 | movl %esp, (%eax)#把esp保存到old指向的地址,esp直接作为context的地址被保存 24 | movl %edx, %esp #切换到new指向的地址 25 | 26 | # Load new callee-save registers 27 | popl %edi 28 | popl %esi 29 | popl %ebx 30 | popl %ebp 31 | #还有一个eip未弹出，刚好由ret弹出 32 | ret 33 | -------------------------------------------------------------------------------- /code/param.h: -------------------------------------------------------------------------------- 1 | #define NPROC 64 // maximum number of processes 2 | #define KSTACKSIZE 4096 // size of per-process kernel stack 3 | #define NCPU 8 // maximum number of CPUs 4 | #define NOFILE 16 // open files per process 5 | #define NFILE 100 // open files per system 6 | #define NINODE 50 // maximum number of active i-nodes 7 | #define NDEV 10 // maximum major device number 8 | #define ROOTDEV 1 // device number of file system root disk 9 | #define MAXARG 32 // max exec arguments 10 | #define MAXOPBLOCKS 10 // max # of blocks any FS op writes 11 | #define LOGSIZE (MAXOPBLOCKS*3) // max data blocks in on-disk log 12 | #define NBUF (MAXOPBLOCKS*3) // size of disk block cache 13 | //#define FSSIZE 1000 // size of file system in blocks 14 | #define FSSIZE 20000 //size of file system in blocks 15 | 16 | -------------------------------------------------------------------------------- /code/elf.h: -------------------------------------------------------------------------------- 1 | // Format of an ELF executable file 2 | 3 | #define ELF_MAGIC 0x464C457FU // "\x7FELF" in little endian 4 | 5 | // File header 6 | struct elfhdr { 7 | uint magic; // must equal ELF_MAGIC 8 | uchar elf[12]; 9 | ushort type; 10 | ushort machine; 11 | uint version; 12 | uint entry; 13 | uint phoff; 14 | uint shoff; 15 | uint flags; 16 | ushort ehsize; 17 | ushort phentsize; 18 | ushort phnum; 19 | ushort shentsize; 20 | ushort shnum; 21 | ushort shstrndx; 22 | }; 23 | 24 | // Program section header 25 | struct proghdr { 26 | uint type; 27 | uint off; 28 | uint vaddr; 29 | uint paddr; 30 | uint filesz; 31 | uint memsz; 32 | uint flags; 33 | uint align; 34 | }; 35 | 36 | // Values for Proghdr type 37 | #define ELF_PROG_LOAD 1 38 | 39 | // Flag bits for Proghdr flags 40 | #define ELF_PROG_FLAG_EXEC 1 41 | #define ELF_PROG_FLAG_WRITE 2 42 | #define ELF_PROG_FLAG_READ 4 43 | -------------------------------------------------------------------------------- /code/file.h: -------------------------------------------------------------------------------- 1 | struct file { 2 | enum { FD_NONE, FD_PIPE, FD_INODE } type; 3 | int ref; // reference count 4 | char readable; 5 | char writable; 6 | struct pipe *pipe; 7 | struct inode *ip; 8 | uint off; 9 | }; 10 | 11 | 12 | // in-memory copy of an inode 13 | struct inode { 14 | uint dev; // Device number 15 | uint inum; // Inode number 16 | int ref; // Reference count 17 | struct sleeplock lock; // protects everything below here 18 | int valid; // inode has been read from disk? 19 | 20 | short type; // copy of disk inode 21 | short major; 22 | short minor; 23 | short nlink; 24 | uint size; 25 | uint addrs[NDIRECT+1]; 26 | }; 27 | 28 | // table mapping major device number to 29 | // device functions 30 | struct devsw { 31 | int (*read)(struct inode*, char*, int); 32 | int (*write)(struct inode*, char*, int); 33 | }; 34 | 35 | extern struct devsw devsw[]; 36 | 37 | #define CONSOLE 1 38 | -------------------------------------------------------------------------------- /code/runoff.list: -------------------------------------------------------------------------------- 1 | # basic headers 2 | types.h 3 | param.h 4 | memlayout.h 5 | defs.h 6 | x86.h 7 | asm.h 8 | mmu.h 9 | elf.h 10 | 11 | # entering xv6 12 | entry.S 13 | entryother.S 14 | main.c 15 | 16 | # locks 17 | spinlock.h 18 | spinlock.c 19 | 20 | # processes 21 | vm.c 22 | proc.h 23 | proc.c 24 | swtch.S 25 | kalloc.c 26 | 27 | # system calls 28 | traps.h 29 | vectors.pl 30 | trapasm.S 31 | trap.c 32 | syscall.h 33 | syscall.c 34 | sysproc.c 35 | 36 | # file system 37 | buf.h 38 | sleeplock.h 39 | fcntl.h 40 | stat.h 41 | fs.h 42 | file.h 43 | ide.c 44 | bio.c 45 | sleeplock.c 46 | log.c 47 | fs.c 48 | file.c 49 | sysfile.c 50 | exec.c 51 | 52 | # pipes 53 | pipe.c 54 | 55 | # string operations 56 | string.c 57 | 58 | # low-level hardware 59 | mp.h 60 | mp.c 61 | lapic.c 62 | ioapic.c 63 | kbd.h 64 | kbd.c 65 | console.c 66 | uart.c 67 | 68 | # user-level 69 | initcode.S 70 | usys.S 71 | init.c 72 | sh.c 73 | 74 | # bootloader 75 | bootasm.S 76 | bootmain.c 77 | 78 | -------------------------------------------------------------------------------- /code/asm.h: -------------------------------------------------------------------------------- 1 | // 2 | // assembler macros to create x86 segments 3 | // 4 | 5 | #define SEG_NULLASM \ 6 | .word 0, 0; \ 7 | .byte 0, 0, 0, 0 8 | 9 | // The 0xC0 means the limit is in 4096-byte units 10 | // and (for executable segments) 32-bit mode. 11 | #define SEG_ASM(type,base,lim) \ 12 | .word (((lim) >> 12) & 0xffff), ((base) & 0xffff); \ 13 | .byte (((base) >> 16) & 0xff), (0x90 | (type)), \ 14 | (0xC0 | (((lim) >> 28) & 0xf)), (((base) >> 24) & 0xff) 15 | 16 | #define STA_X 0x8 // Executable segment 17 | #define STA_E 0x4 // Expand down (non-executable segments) 18 | #define STA_C 0x4 // Conforming code segment (executable only) 19 | #define STA_W 0x2 // Writeable (non-executable segments) 20 | #define STA_R 0x2 // Readable (executable segments) 21 | #define STA_A 0x1 // Accessed 22 | -------------------------------------------------------------------------------- /code/forktest.c: -------------------------------------------------------------------------------- 1 | // Test that fork fails gracefully. 2 | // Tiny executable so that the limit can be filling the proc table. 3 | 4 | #include "types.h" 5 | #include "stat.h" 6 | #include "user.h" 7 | 8 | #define N 1000 9 | 10 | void 11 | printf(int fd, char *s, ...) 12 | { 13 | write(fd, s, strlen(s)); 14 | } 15 | 16 | void 17 | forktest(void) 18 | { 19 | int n, pid; 20 | 21 | printf(1, "fork test\n"); 22 | 23 | for(n=0; n 0; n--){ 37 | if(wait() < 0){ 38 | printf(1, "wait stopped early\n"); 39 | exit(); 40 | } 41 | } 42 | 43 | if(wait() != -1){ 44 | printf(1, "wait got too many\n"); 45 | exit(); 46 | } 47 | 48 | printf(1, "fork test OK\n"); 49 | } 50 | 51 | int 52 | main(void) 53 | { 54 | forktest(); 55 | exit(); 56 | } 57 | -------------------------------------------------------------------------------- /code/sleeplock.c: -------------------------------------------------------------------------------- 1 | // Sleeping locks 2 | 3 | #include "types.h" 4 | #include "defs.h" 5 | #include "param.h" 6 | #include "x86.h" 7 | #include "memlayout.h" 8 | #include "mmu.h" 9 | #include "proc.h" 10 | #include "spinlock.h" 11 | #include "sleeplock.h" 12 | 13 | void 14 | initsleeplock(struct sleeplock *lk, char *name) 15 | { 16 | initlock(&lk->lk, "sleep lock"); 17 | lk->name = name; 18 | lk->locked = 0; 19 | lk->pid = 0; 20 | } 21 | 22 | void 23 | acquiresleep(struct sleeplock *lk) 24 | { 25 | acquire(&lk->lk); 26 | while (lk->locked) { 27 | sleep(lk, &lk->lk); 28 | } 29 | lk->locked = 1; 30 | lk->pid = myproc()->pid; 31 | release(&lk->lk); 32 | } 33 | 34 | void 35 | releasesleep(struct sleeplock *lk) 36 | { 37 | acquire(&lk->lk); 38 | lk->locked = 0; 39 | lk->pid = 0; 40 | wakeup(lk); 41 | release(&lk->lk); 42 | } 43 | 44 | int 45 | holdingsleep(struct sleeplock *lk) 46 | { 47 | int r; 48 | 49 | acquire(&lk->lk); 50 | r = lk->locked; 51 | release(&lk->lk); 52 | return r; 53 | } 54 | 55 | 56 | 57 | -------------------------------------------------------------------------------- /code/wc.c: -------------------------------------------------------------------------------- 1 | #include "types.h" 2 | #include "stat.h" 3 | #include "user.h" 4 | 5 | char buf[512]; 6 | 7 | void 8 | wc(int fd, char *name) 9 | { 10 | int i, n; 11 | int l, w, c, inword; 12 | 13 | l = w = c = 0; 14 | inword = 0; 15 | while((n = read(fd, buf, sizeof(buf))) > 0){ 16 | for(i=0; i$file") || die "open >$file: $!"; 10 | print F @lines; 11 | close(F); 12 | } 13 | 14 | # Cut out #include lines that don't contribute anything. 15 | for($i=0; $i<@ARGV; $i++){ 16 | $file = $ARGV[$i]; 17 | if(!open(F, $file)){ 18 | print STDERR "open $file: $!\n"; 19 | next; 20 | } 21 | @lines = ; 22 | close(F); 23 | 24 | $obj = "$file.o"; 25 | $obj =~ s/\.c\.o$/.o/; 26 | system("touch $file"); 27 | 28 | if(system("make CC='gcc -Werror' $obj >/dev/null 2>\&1") != 0){ 29 | print STDERR "make $obj failed: $rv\n"; 30 | next; 31 | } 32 | 33 | system("cp $file =$file"); 34 | for($j=@lines-1; $j>=0; $j--){ 35 | if($lines[$j] =~ /^#include/){ 36 | $old = $lines[$j]; 37 | $lines[$j] = "/* CUT-H */\n"; 38 | writefile($file, @lines); 39 | if(system("make CC='gcc -Werror' $obj >/dev/null 2>\&1") != 0){ 40 | $lines[$j] = $old; 41 | }else{ 42 | print STDERR "$file $old"; 43 | } 44 | } 45 | } 46 | writefile($file, grep {!/CUT-H/} @lines); 47 | system("rm =$file"); 48 | } 49 | -------------------------------------------------------------------------------- /code/kbd.c: -------------------------------------------------------------------------------- 1 | #include "types.h" 2 | #include "x86.h" 3 | #include "defs.h" 4 | #include "kbd.h" 5 | 6 | int 7 | kbdgetc(void) 8 | { 9 | static uint shift; 10 | static uchar *charcode[4] = { 11 | normalmap, shiftmap, ctlmap, ctlmap 12 | }; 13 | uint st, data, c; 14 | 15 | st = inb(KBSTATP); 16 | if((st & KBS_DIB) == 0) 17 | return -1; 18 | data = inb(KBDATAP); 19 | 20 | if(data == 0xE0){ 21 | shift |= E0ESC; 22 | return 0; 23 | } else if(data & 0x80){ 24 | // Key released 25 | data = (shift & E0ESC ? data : data & 0x7F); 26 | shift &= ~(shiftcode[data] | E0ESC); 27 | return 0; 28 | } else if(shift & E0ESC){ 29 | // Last character was an E0 escape; or with 0x80 30 | data |= 0x80; 31 | shift &= ~E0ESC; 32 | } 33 | 34 | shift |= shiftcode[data]; 35 | shift ^= togglecode[data]; 36 | c = charcode[shift & (CTL | SHIFT)][data]; 37 | if(shift & CAPSLOCK){ 38 | if('a' <= c && c <= 'z') 39 | c += 'A' - 'a'; 40 | else if('A' <= c && c <= 'Z') 41 | c += 'a' - 'A'; 42 | } 43 | return c; 44 | } 45 | 46 | void 47 | kbdintr(void) 48 | { 49 | consoleintr(kbdgetc); 50 | } 51 | -------------------------------------------------------------------------------- /code/vectors.pl: -------------------------------------------------------------------------------- 1 | #!/usr/bin/perl -w 2 | 3 | # Generate vectors.S, the trap/interrupt entry points. 4 | # There has to be one entry point per interrupt number 5 | # since otherwise there's no way for trap() to discover 6 | # the interrupt number. 7 | 8 | print "# generated by vectors.pl - do not edit\n"; 9 | print "# handlers\n"; 10 | print ".globl alltraps\n"; 11 | for(my $i = 0; $i < 256; $i++){ 12 | print ".globl vector$i\n"; 13 | print "vector$i:\n"; 14 | if(!($i == 8 || ($i >= 10 && $i <= 14) || $i == 17)){ 15 | print " pushl \$0\n"; 16 | } 17 | print " pushl \$$i\n"; 18 | print " jmp alltraps\n"; 19 | } 20 | 21 | print "\n# vector table\n"; 22 | print ".data\n"; 23 | print ".globl vectors\n"; 24 | print "vectors:\n"; 25 | for(my $i = 0; $i < 256; $i++){ 26 | print " .long vector$i\n"; 27 | } 28 | 29 | # sample output: 30 | # # handlers 31 | # .globl alltraps 32 | # .globl vector0 33 | # vector0: 34 | # pushl $0 35 | # pushl $0 36 | # jmp alltraps 37 | # ... 38 | # 39 | # # vector table 40 | # .data 41 | # .globl vectors 42 | # vectors: 43 | # .long vector0 44 | # .long vector1 45 | # .long vector2 46 | # ... 47 | 48 | -------------------------------------------------------------------------------- /code/big.c: -------------------------------------------------------------------------------- 1 | #include "types.h" 2 | #include "stat.h" 3 | #include "user.h" 4 | #include "fcntl.h" 5 | 6 | int 7 | main() 8 | { 9 | char buf[512]; 10 | int fd, i, sectors; 11 | 12 | fd = open("big.file", O_CREATE | O_WRONLY); 13 | if(fd < 0){ 14 | printf(2, "big: cannot open big.file for writing\n"); 15 | exit(); 16 | } 17 | 18 | sectors = 0; 19 | while(1){ 20 | *(int*)buf = sectors; 21 | int cc = write(fd, buf, sizeof(buf)); 22 | if(cc <= 0) 23 | break; 24 | sectors++; 25 | if (sectors % 100 == 0) 26 | printf(2, "."); 27 | } 28 | 29 | printf(1, "\nwrote %d sectors\n", sectors); 30 | 31 | close(fd); 32 | fd = open("big.file", O_RDONLY); 33 | if(fd < 0){ 34 | printf(2, "big: cannot re-open big.file for reading\n"); 35 | exit(); 36 | } 37 | for(i = 0; i < sectors; i++){ 38 | int cc = read(fd, buf, sizeof(buf)); 39 | if(cc <= 0){ 40 | printf(2, "big: read error at sector %d\n", i); 41 | exit(); 42 | } 43 | if(*(int*)buf != i){ 44 | printf(2, "big: read the wrong data (%d) for sector %d\n", 45 | *(int*)buf, i); 46 | exit(); 47 | } 48 | } 49 | 50 | printf(1, "done; ok\n"); 51 | 52 | exit(); 53 | } 54 | -------------------------------------------------------------------------------- /code/stressfs.c: -------------------------------------------------------------------------------- 1 | // Demonstrate that moving the "acquire" in iderw after the loop that 2 | // appends to the idequeue results in a race. 3 | 4 | // For this to work, you should also add a spin within iderw's 5 | // idequeue traversal loop. Adding the following demonstrated a panic 6 | // after about 5 runs of stressfs in QEMU on a 2.1GHz CPU: 7 | // for (i = 0; i < 40000; i++) 8 | // asm volatile(""); 9 | 10 | #include "types.h" 11 | #include "stat.h" 12 | #include "user.h" 13 | #include "fs.h" 14 | #include "fcntl.h" 15 | 16 | int 17 | main(int argc, char *argv[]) 18 | { 19 | int fd, i; 20 | char path[] = "stressfs0"; 21 | char data[512]; 22 | 23 | printf(1, "stressfs starting\n"); 24 | memset(data, 'a', sizeof(data)); 25 | 26 | for(i = 0; i < 4; i++) 27 | if(fork() > 0) 28 | break; 29 | 30 | printf(1, "write %d\n", i); 31 | 32 | path[8] += i; 33 | fd = open(path, O_CREATE | O_RDWR); 34 | for(i = 0; i < 20; i++) 35 | // printf(fd, "%d\n", i); 36 | write(fd, data, sizeof(data)); 37 | close(fd); 38 | 39 | printf(1, "read\n"); 40 | 41 | fd = open(path, O_RDONLY); 42 | for (i = 0; i < 20; i++) 43 | read(fd, data, sizeof(data)); 44 | close(fd); 45 | 46 | wait(); 47 | 48 | exit(); 49 | } 50 | -------------------------------------------------------------------------------- /code/LICENSE: -------------------------------------------------------------------------------- 1 | The xv6 software is: 2 | 3 | Copyright (c) 2006-2017 Frans Kaashoek, Robert Morris, Russ Cox, 4 | Massachusetts Institute of Technology 5 | 6 | Permission is hereby granted, free of charge, to any person obtaining 7 | a copy of this software and associated documentation files (the 8 | "Software"), to deal in the Software without restriction, including 9 | without limitation the rights to use, copy, modify, merge, publish, 10 | distribute, sublicense, and/or sell copies of the Software, and to 11 | permit persons to whom the Software is furnished to do so, subject to 12 | the following conditions: 13 | 14 | The above copyright notice and this permission notice shall be 15 | included in all copies or substantial portions of the Software. 16 | 17 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 18 | EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 19 | MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 20 | NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE 21 | LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION 22 | OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION 23 | WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 24 | 25 | -------------------------------------------------------------------------------- /code/memide.c: -------------------------------------------------------------------------------- 1 | // Fake IDE disk; stores blocks in memory. 2 | // Useful for running kernel without scratch disk. 3 | 4 | #include "types.h" 5 | #include "defs.h" 6 | #include "param.h" 7 | #include "mmu.h" 8 | #include "proc.h" 9 | #include "x86.h" 10 | #include "traps.h" 11 | #include "spinlock.h" 12 | #include "sleeplock.h" 13 | #include "fs.h" 14 | #include "buf.h" 15 | 16 | extern uchar _binary_fs_img_start[], _binary_fs_img_size[]; 17 | 18 | static int disksize; 19 | static uchar *memdisk; 20 | 21 | void 22 | ideinit(void) 23 | { 24 | memdisk = _binary_fs_img_start; 25 | disksize = (uint)_binary_fs_img_size/BSIZE; 26 | } 27 | 28 | // Interrupt handler. 29 | void 30 | ideintr(void) 31 | { 32 | // no-op 33 | } 34 | 35 | // Sync buf with disk. 36 | // If B_DIRTY is set, write buf to disk, clear B_DIRTY, set B_VALID. 37 | // Else if B_VALID is not set, read buf from disk, set B_VALID. 38 | void 39 | iderw(struct buf *b) 40 | { 41 | uchar *p; 42 | 43 | if(!holdingsleep(&b->lock)) 44 | panic("iderw: buf not locked"); 45 | if((b->flags & (B_VALID|B_DIRTY)) == B_VALID) 46 | panic("iderw: nothing to do"); 47 | if(b->dev != 1) 48 | panic("iderw: request not for disk 1"); 49 | if(b->blockno >= disksize) 50 | panic("iderw: block out of range"); 51 | 52 | p = memdisk + b->blockno*BSIZE; 53 | 54 | if(b->flags & B_DIRTY){ 55 | b->flags &= ~B_DIRTY; 56 | memmove(p, b->data, BSIZE); 57 | } else 58 | memmove(b->data, p, BSIZE); 59 | b->flags |= B_VALID; 60 | } 61 | -------------------------------------------------------------------------------- /code/uart.c: -------------------------------------------------------------------------------- 1 | // Intel 8250 serial port (UART). 2 | 3 | #include "types.h" 4 | #include "defs.h" 5 | #include "param.h" 6 | #include "traps.h" 7 | #include "spinlock.h" 8 | #include "sleeplock.h" 9 | #include "fs.h" 10 | #include "file.h" 11 | #include "mmu.h" 12 | #include "proc.h" 13 | #include "x86.h" 14 | 15 | #define COM1 0x3f8 16 | 17 | static int uart; // is there a uart? 18 | 19 | void 20 | uartinit(void) 21 | { 22 | char *p; 23 | 24 | // Turn off the FIFO 25 | outb(COM1+2, 0); 26 | 27 | // 9600 baud, 8 data bits, 1 stop bit, parity off. 28 | outb(COM1+3, 0x80); // Unlock divisor 29 | outb(COM1+0, 115200/9600); 30 | outb(COM1+1, 0); 31 | outb(COM1+3, 0x03); // Lock divisor, 8 data bits. 32 | outb(COM1+4, 0); 33 | outb(COM1+1, 0x01); // Enable receive interrupts. 34 | 35 | // If status is 0xFF, no serial port. 36 | if(inb(COM1+5) == 0xFF) 37 | return; 38 | uart = 1; 39 | 40 | // Acknowledge pre-existing interrupt conditions; 41 | // enable interrupts. 42 | inb(COM1+2); 43 | inb(COM1+0); 44 | ioapicenable(IRQ_COM1, 0); 45 | 46 | // Announce that we're here. 47 | for(p="xv6...\n"; *p; p++) 48 | uartputc(*p); 49 | } 50 | 51 | void 52 | uartputc(int c) 53 | { 54 | int i; 55 | 56 | if(!uart) 57 | return; 58 | for(i = 0; i < 128 && !(inb(COM1+5) & 0x20); i++) 59 | microdelay(10); 60 | outb(COM1+0, c); 61 | } 62 | 63 | static int 64 | uartgetc(void) 65 | { 66 | if(!uart) 67 | return -1; 68 | if(!(inb(COM1+5) & 0x01)) 69 | return -1; 70 | return inb(COM1+0); 71 | } 72 | 73 | void 74 | uartintr(void) 75 | { 76 | consoleintr(uartgetc); 77 | } 78 | -------------------------------------------------------------------------------- /code/traps.h: -------------------------------------------------------------------------------- 1 | // x86 trap and interrupt constants. 2 | 3 | // Processor-defined: 4 | #define T_DIVIDE 0 // divide error 5 | #define T_DEBUG 1 // debug exception 6 | #define T_NMI 2 // non-maskable interrupt 7 | #define T_BRKPT 3 // breakpoint 8 | #define T_OFLOW 4 // overflow 9 | #define T_BOUND 5 // bounds check 10 | #define T_ILLOP 6 // illegal opcode 11 | #define T_DEVICE 7 // device not available 12 | #define T_DBLFLT 8 // double fault 13 | // #define T_COPROC 9 // reserved (not used since 486) 14 | #define T_TSS 10 // invalid task switch segment 15 | #define T_SEGNP 11 // segment not present 16 | #define T_STACK 12 // stack exception 17 | #define T_GPFLT 13 // general protection fault 18 | #define T_PGFLT 14 // page fault 19 | // #define T_RES 15 // reserved 20 | #define T_FPERR 16 // floating point error 21 | #define T_ALIGN 17 // aligment check 22 | #define T_MCHK 18 // machine check 23 | #define T_SIMDERR 19 // SIMD floating point error 24 | 25 | // These are arbitrarily chosen, but with care not to overlap 26 | // processor defined exceptions or interrupt vectors. 27 | #define T_SYSCALL 64 // system call 28 | #define T_DEFAULT 500 // catchall 29 | 30 | #define T_IRQ0 32 // IRQ 0 corresponds to int T_IRQ 31 | 32 | #define IRQ_TIMER 0 33 | #define IRQ_KBD 1 34 | #define IRQ_COM1 4 35 | #define IRQ_IDE 14 36 | #define IRQ_ERROR 19 37 | #define IRQ_SPURIOUS 31 38 | 39 | -------------------------------------------------------------------------------- /code/ulib.c: -------------------------------------------------------------------------------- 1 | #include "types.h" 2 | #include "stat.h" 3 | #include "fcntl.h" 4 | #include "user.h" 5 | #include "x86.h" 6 | 7 | char* 8 | strcpy(char *s, char *t) 9 | { 10 | char *os; 11 | 12 | os = s; 13 | while((*s++ = *t++) != 0) 14 | ; 15 | return os; 16 | } 17 | 18 | int 19 | strcmp(const char *p, const char *q) 20 | { 21 | while(*p && *p == *q) 22 | p++, q++; 23 | return (uchar)*p - (uchar)*q; 24 | } 25 | 26 | uint 27 | strlen(char *s) 28 | { 29 | int n; 30 | 31 | for(n = 0; s[n]; n++) 32 | ; 33 | return n; 34 | } 35 | 36 | void* 37 | memset(void *dst, int c, uint n) 38 | { 39 | stosb(dst, c, n); 40 | return dst; 41 | } 42 | 43 | char* 44 | strchr(const char *s, char c) 45 | { 46 | for(; *s; s++) 47 | if(*s == c) 48 | return (char*)s; 49 | return 0; 50 | } 51 | 52 | char* 53 | gets(char *buf, int max) 54 | { 55 | int i, cc; 56 | char c; 57 | 58 | for(i=0; i+1 < max; ){ 59 | cc = read(0, &c, 1); 60 | if(cc < 1) 61 | break; 62 | buf[i++] = c; 63 | if(c == '\n' || c == '\r') 64 | break; 65 | } 66 | buf[i] = '\0'; 67 | return buf; 68 | } 69 | 70 | int 71 | stat(char *n, struct stat *st) 72 | { 73 | int fd; 74 | int r; 75 | 76 | fd = open(n, O_RDONLY); 77 | if(fd < 0) 78 | return -1; 79 | r = fstat(fd, st); 80 | close(fd); 81 | return r; 82 | } 83 | 84 | int 85 | atoi(const char *s) 86 | { 87 | int n; 88 | 89 | n = 0; 90 | while('0' <= *s && *s <= '9') 91 | n = n*10 + *s++ - '0'; 92 | return n; 93 | } 94 | 95 | void* 96 | memmove(void *vdst, void *vsrc, int n) 97 | { 98 | char *dst, *src; 99 | 100 | dst = vdst; 101 | src = vsrc; 102 | while(n-- > 0) 103 | *dst++ = *src++; 104 | return vdst; 105 | } 106 | -------------------------------------------------------------------------------- /code/printf.c: -------------------------------------------------------------------------------- 1 | #include "types.h" 2 | #include "stat.h" 3 | #include "user.h" 4 | 5 | static void 6 | putc(int fd, char c) 7 | { 8 | write(fd, &c, 1); 9 | } 10 | 11 | static void 12 | printint(int fd, int xx, int base, int sgn) 13 | { 14 | static char digits[] = "0123456789ABCDEF"; 15 | char buf[16]; 16 | int i, neg; 17 | uint x; 18 | 19 | neg = 0; 20 | if(sgn && xx < 0){ 21 | neg = 1; 22 | x = -xx; 23 | } else { 24 | x = xx; 25 | } 26 | 27 | i = 0; 28 | do{ 29 | buf[i++] = digits[x % base]; 30 | }while((x /= base) != 0); 31 | if(neg) 32 | buf[i++] = '-'; 33 | 34 | while(--i >= 0) 35 | putc(fd, buf[i]); 36 | } 37 | 38 | // Print to the given fd. Only understands %d, %x, %p, %s. 39 | void 40 | printf(int fd, char *fmt, ...) 41 | { 42 | char *s; 43 | int c, i, state; 44 | uint *ap; 45 | 46 | state = 0; 47 | ap = (uint*)(void*)&fmt + 1; 48 | for(i = 0; fmt[i]; i++){ 49 | c = fmt[i] & 0xff; 50 | if(state == 0){ 51 | if(c == '%'){ 52 | state = '%'; 53 | } else { 54 | putc(fd, c); 55 | } 56 | } else if(state == '%'){ 57 | if(c == 'd'){ 58 | printint(fd, *ap, 10, 1); 59 | ap++; 60 | } else if(c == 'x' || c == 'p'){ 61 | printint(fd, *ap, 16, 0); 62 | ap++; 63 | } else if(c == 's'){ 64 | s = (char*)*ap; 65 | ap++; 66 | if(s == 0) 67 | s = "(null)"; 68 | while(*s != 0){ 69 | putc(fd, *s); 70 | s++; 71 | } 72 | } else if(c == 'c'){ 73 | putc(fd, *ap); 74 | ap++; 75 | } else if(c == '%'){ 76 | putc(fd, c); 77 | } else { 78 | // Unknown % sequence. Print it to draw attention. 79 | putc(fd, '%'); 80 | putc(fd, c); 81 | } 82 | state = 0; 83 | } 84 | } 85 | } 86 | -------------------------------------------------------------------------------- /code/kernel.ld: -------------------------------------------------------------------------------- 1 | /* Simple linker script for the JOS kernel. 2 | See the GNU ld 'info' manual ("info ld") to learn the syntax. */ 3 | 4 | OUTPUT_FORMAT("elf32-i386", "elf32-i386", "elf32-i386") 5 | OUTPUT_ARCH(i386) 6 | ENTRY(_start) 7 | 8 | SECTIONS 9 | { 10 | /* Link the kernel at this address: "." means the current address */ 11 | /* Must be equal to KERNLINK */ 12 | . = 0x80100000; 13 | 14 | .text : AT(0x100000) { 15 | *(.text .stub .text.* .gnu.linkonce.t.*) 16 | } 17 | 18 | PROVIDE(etext = .); /* Define the 'etext' symbol to this value */ 19 | 20 | .rodata : { 21 | *(.rodata .rodata.* .gnu.linkonce.r.*) 22 | } 23 | 24 | /* Include debugging information in kernel memory */ 25 | .stab : { 26 | PROVIDE(__STAB_BEGIN__ = .); 27 | *(.stab); 28 | PROVIDE(__STAB_END__ = .); 29 | BYTE(0) /* Force the linker to allocate space 30 | for this section */ 31 | } 32 | 33 | .stabstr : { 34 | PROVIDE(__STABSTR_BEGIN__ = .); 35 | *(.stabstr); 36 | PROVIDE(__STABSTR_END__ = .); 37 | BYTE(0) /* Force the linker to allocate space 38 | for this section */ 39 | } 40 | 41 | /* Adjust the address for the data segment to the next page */ 42 | . = ALIGN(0x1000); 43 | 44 | /* Conventionally, Unix linkers provide pseudo-symbols 45 | * etext, edata, and end, at the end of the text, data, and bss. 46 | * For the kernel mapping, we need the address at the beginning 47 | * of the data section, but that's not one of the conventional 48 | * symbols, because the convention started before there was a 49 | * read-only rodata section between text and data. */ 50 | PROVIDE(data = .); 51 | 52 | /* The data segment */ 53 | .data : { 54 | *(.data) 55 | } 56 | 57 | PROVIDE(edata = .); 58 | 59 | .bss : { 60 | *(.bss) 61 | } 62 | 63 | PROVIDE(end = .); 64 | 65 | /DISCARD/ : { 66 | *(.eh_frame .note.GNU-stack) 67 | } 68 | } 69 | -------------------------------------------------------------------------------- /code/ls.c: -------------------------------------------------------------------------------- 1 | #include "types.h" 2 | #include "stat.h" 3 | #include "user.h" 4 | #include "fs.h" 5 | 6 | char* 7 | fmtname(char *path) 8 | { 9 | static char buf[DIRSIZ+1]; 10 | char *p; 11 | 12 | // Find first character after last slash. 13 | for(p=path+strlen(path); p >= path && *p != '/'; p--) 14 | ; 15 | p++; 16 | 17 | // Return blank-padded name. 18 | if(strlen(p) >= DIRSIZ) 19 | return p; 20 | memmove(buf, p, strlen(p)); 21 | memset(buf+strlen(p), ' ', DIRSIZ-strlen(p)); 22 | return buf; 23 | } 24 | 25 | void 26 | ls(char *path) 27 | { 28 | char buf[512], *p; 29 | int fd; 30 | struct dirent de; 31 | struct stat st; 32 | 33 | if((fd = open(path, 0)) < 0){ 34 | printf(2, "ls: cannot open %s\n", path); 35 | return; 36 | } 37 | 38 | if(fstat(fd, &st) < 0){ 39 | printf(2, "ls: cannot stat %s\n", path); 40 | close(fd); 41 | return; 42 | } 43 | 44 | switch(st.type){ 45 | case T_FILE: 46 | printf(1, "%s %d %d %d\n", fmtname(path), st.type, st.ino, st.size); 47 | break; 48 | 49 | case T_DIR: 50 | if(strlen(path) + 1 + DIRSIZ + 1 > sizeof buf){ 51 | printf(1, "ls: path too long\n"); 52 | break; 53 | } 54 | strcpy(buf, path); 55 | p = buf+strlen(buf); 56 | *p++ = '/'; 57 | while(read(fd, &de, sizeof(de)) == sizeof(de)){ 58 | if(de.inum == 0) 59 | continue; 60 | memmove(p, de.name, DIRSIZ); 61 | p[DIRSIZ] = 0; 62 | if(stat(buf, &st) < 0){ 63 | printf(1, "ls: cannot stat %s\n", buf); 64 | continue; 65 | } 66 | printf(1, "%s %d %d %d\n", fmtname(buf), st.type, st.ino, st.size); 67 | } 68 | break; 69 | } 70 | close(fd); 71 | } 72 | 73 | int 74 | main(int argc, char *argv[]) 75 | { 76 | int i; 77 | 78 | if(argc < 2){ 79 | ls("."); 80 | exit(); 81 | } 82 | for(i=1; i 0){ 23 | if(*s1 != *s2) 24 | return *s1 - *s2; 25 | s1++, s2++; 26 | } 27 | 28 | return 0; 29 | } 30 | 31 | void* 32 | memmove(void *dst, const void *src, uint n) 33 | { 34 | const char *s; 35 | char *d; 36 | 37 | s = src; 38 | d = dst; 39 | if(s < d && s + n > d){ 40 | s += n; 41 | d += n; 42 | while(n-- > 0) 43 | *--d = *--s; 44 | } else 45 | while(n-- > 0) 46 | *d++ = *s++; 47 | 48 | return dst; 49 | } 50 | 51 | // memcpy exists to placate GCC. Use memmove. 52 | void* 53 | memcpy(void *dst, const void *src, uint n) 54 | { 55 | return memmove(dst, src, n); 56 | } 57 | 58 | int 59 | strncmp(const char *p, const char *q, uint n) 60 | { 61 | while(n > 0 && *p && *p == *q) 62 | n--, p++, q++; 63 | if(n == 0) 64 | return 0; 65 | return (uchar)*p - (uchar)*q; 66 | } 67 | 68 | char* 69 | strncpy(char *s, const char *t, int n) 70 | { 71 | char *os; 72 | 73 | os = s; 74 | while(n-- > 0 && (*s++ = *t++) != 0) 75 | ; 76 | while(n-- > 0) 77 | *s++ = 0; 78 | return os; 79 | } 80 | 81 | // Like strncpy but guaranteed to NUL-terminate. 82 | char* 83 | safestrcpy(char *s, const char *t, int n) 84 | { 85 | char *os; 86 | 87 | os = s; 88 | if(n <= 0) 89 | return os; 90 | while(--n > 0 && (*s++ = *t++) != 0) 91 | ; 92 | *s = 0; 93 | return os; 94 | } 95 | 96 | int 97 | strlen(const char *s) 98 | { 99 | int n; 100 | 101 | for(n = 0; s[n]; n++) 102 | ; 103 | return n; 104 | } 105 | 106 | -------------------------------------------------------------------------------- /code/umalloc.c: -------------------------------------------------------------------------------- 1 | #include "types.h" 2 | #include "stat.h" 3 | #include "user.h" 4 | #include "param.h" 5 | 6 | // Memory allocator by Kernighan and Ritchie, 7 | // The C programming Language, 2nd ed. Section 8.7. 8 | 9 | typedef long Align; 10 | 11 | union header { 12 | struct { 13 | union header *ptr; 14 | uint size; 15 | } s; 16 | Align x; 17 | }; 18 | 19 | typedef union header Header; 20 | 21 | static Header base; 22 | static Header *freep; 23 | 24 | void 25 | free(void *ap) 26 | { 27 | Header *bp, *p; 28 | 29 | bp = (Header*)ap - 1; 30 | for(p = freep; !(bp > p && bp < p->s.ptr); p = p->s.ptr) 31 | if(p >= p->s.ptr && (bp > p || bp < p->s.ptr)) 32 | break; 33 | if(bp + bp->s.size == p->s.ptr){ 34 | bp->s.size += p->s.ptr->s.size; 35 | bp->s.ptr = p->s.ptr->s.ptr; 36 | } else 37 | bp->s.ptr = p->s.ptr; 38 | if(p + p->s.size == bp){ 39 | p->s.size += bp->s.size; 40 | p->s.ptr = bp->s.ptr; 41 | } else 42 | p->s.ptr = bp; 43 | freep = p; 44 | } 45 | 46 | static Header* 47 | morecore(uint nu) 48 | { 49 | char *p; 50 | Header *hp; 51 | 52 | if(nu < 4096) 53 | nu = 4096; 54 | p = sbrk(nu * sizeof(Header)); 55 | if(p == (char*)-1) 56 | return 0; 57 | hp = (Header*)p; 58 | hp->s.size = nu; 59 | free((void*)(hp + 1)); 60 | return freep; 61 | } 62 | 63 | void* 64 | malloc(uint nbytes) 65 | { 66 | Header *p, *prevp; 67 | uint nunits; 68 | 69 | nunits = (nbytes + sizeof(Header) - 1)/sizeof(Header) + 1; 70 | if((prevp = freep) == 0){ 71 | base.s.ptr = freep = prevp = &base; 72 | base.s.size = 0; 73 | } 74 | for(p = prevp->s.ptr; ; prevp = p, p = p->s.ptr){ 75 | if(p->s.size >= nunits){ 76 | if(p->s.size == nunits) 77 | prevp->s.ptr = p->s.ptr; 78 | else { 79 | p->s.size -= nunits; 80 | p += p->s.size; 81 | p->s.size = nunits; 82 | } 83 | freep = prevp; 84 | return (void*)(p + 1); 85 | } 86 | if(p == freep) 87 | if((p = morecore(nunits)) == 0) 88 | return 0; 89 | } 90 | } 91 | -------------------------------------------------------------------------------- /code/fs.h: -------------------------------------------------------------------------------- 1 | // On-disk file system format. 2 | // Both the kernel and user programs use this header file. 3 | 4 | 5 | #define ROOTINO 1 // root i-number 6 | #define BSIZE 512 // block size 7 | 8 | // Disk layout: 9 | // [ boot block | super block | log | inode blocks | 10 | // free bit map | data blocks] 11 | // 12 | // mkfs computes the super block and builds an initial file system. The 13 | // super block describes the disk layout: 14 | struct superblock { 15 | uint size; // Size of file system image (blocks) 16 | uint nblocks; // Number of data blocks 17 | uint ninodes; // Number of inodes. 18 | uint nlog; // Number of log blocks 19 | uint logstart; // Block number of first log block 20 | uint inodestart; // Block number of first inode block 21 | uint bmapstart; // Block number of first free map block 22 | }; 23 | 24 | #define NDIRECT 11 25 | #define DNINDIRECT 12 26 | #define NINDIRECT (BSIZE / sizeof(uint)) 27 | #define DNINDIRECTSIZE NINDIRECT*NINDIRECT 28 | #define MAXFILE (NDIRECT + NINDIRECT+NINDIRECT*NINDIRECT) 29 | 30 | // On-disk inode structure 31 | struct dinode { 32 | short type; // File type 33 | short major; // Major device number (T_DEV only) 34 | short minor; // Minor device number (T_DEV only) 35 | short nlink; // Number of links to inode in file system 36 | uint size; // Size of file (bytes) 37 | uint addrs[DNINDIRECT+1]; // Data block addresses 38 | }; 39 | 40 | // Inodes per block. 41 | #define IPB (BSIZE / sizeof(struct dinode)) 42 | 43 | // Block containing inode i 44 | #define IBLOCK(i, sb) ((i) / IPB + sb.inodestart) 45 | 46 | // Bitmap bits per block 47 | #define BPB (BSIZE*8) 48 | 49 | // Block of free map containing bit for block b 50 | #define BBLOCK(b, sb) (b/BPB + sb.bmapstart) 51 | 52 | // Directory is a file containing a sequence of dirent structures. 53 | #define DIRSIZ 14 54 | 55 | struct dirent { 56 | ushort inum; //the name's file inode number 57 | char name[DIRSIZ]; 58 | }; 59 | 60 | -------------------------------------------------------------------------------- /code/entry.S: -------------------------------------------------------------------------------- 1 | # The xv6 kernel starts executing in this file. This file is linked with 2 | # the kernel C code, so it can refer to kernel symbols such as main(). 3 | # The boot block (bootasm.S and bootmain.c) jumps to entry below. 4 | 5 | # Multiboot header, for multiboot boot loaders like GNU Grub. 6 | # http://www.gnu.org/software/grub/manual/multiboot/multiboot.html 7 | # 8 | # Using GRUB 2, you can boot xv6 from a file stored in a 9 | # Linux file system by copying kernel or kernelmemfs to /boot 10 | # and then adding this menu entry: 11 | # 12 | # menuentry "xv6" { 13 | # insmod ext2 14 | # set root='(hd0,msdos1)' 15 | # set kernel='/boot/kernel' 16 | # echo "Loading ${kernel}..." 17 | # multiboot ${kernel} ${kernel} 18 | # boot 19 | # } 20 | 21 | #include "asm.h" 22 | #include "memlayout.h" 23 | #include "mmu.h" 24 | #include "param.h" 25 | 26 | # Multiboot header. Data to direct multiboot loader. 27 | .p2align 2 28 | .text 29 | .globl multiboot_header 30 | multiboot_header: 31 | #define magic 0x1badb002 32 | #define flags 0 33 | .long magic 34 | .long flags 35 | .long (-magic-flags) 36 | 37 | # By convention, the _start symbol specifies the ELF entry point. 38 | # Since we haven't set up virtual memory yet, our entry point is 39 | # the physical address of 'entry'. 40 | .globl _start 41 | _start = V2P_WO(entry) 42 | 43 | # Entering xv6 on boot processor, with paging off. 44 | .globl entry 45 | entry: 46 | # Turn on page size extension for 4Mbyte pages 47 | movl %cr4, %eax 48 | orl $(CR4_PSE), %eax 49 | movl %eax, %cr4 50 | # Set page directory 51 | movl $(V2P_WO(entrypgdir)), %eax 52 | movl %eax, %cr3 53 | # Turn on paging. 54 | movl %cr0, %eax 55 | orl $(CR0_PG|CR0_WP), %eax 56 | movl %eax, %cr0 57 | 58 | # Set up the stack pointer. 59 | movl $(stack + KSTACKSIZE), %esp 60 | 61 | # Jump to main(), and switch to executing at 62 | # high addresses. The indirect call is needed because 63 | # the assembler produces a PC-relative instruction 64 | # for a direct jump. 65 | mov $main, %eax 66 | jmp *%eax 67 | 68 | .comm stack, KSTACKSIZE 69 | -------------------------------------------------------------------------------- /code/sysproc.c: -------------------------------------------------------------------------------- 1 | #include "types.h" 2 | #include "x86.h" 3 | #include "defs.h" 4 | #include "date.h" 5 | #include "param.h" 6 | #include "memlayout.h" 7 | #include "mmu.h" 8 | #include "proc.h" 9 | 10 | int 11 | sys_fork(void) 12 | { 13 | return fork(); 14 | } 15 | 16 | int 17 | sys_exit(void) 18 | { 19 | exit(); 20 | return 0; // not reached 21 | } 22 | 23 | int 24 | sys_wait(void) 25 | { 26 | return wait(); 27 | } 28 | 29 | int 30 | sys_kill(void) 31 | { 32 | int pid; 33 | 34 | if(argint(0, &pid) < 0) 35 | return -1; 36 | return kill(pid); 37 | } 38 | 39 | int 40 | sys_getpid(void) 41 | { 42 | return myproc()->pid; 43 | } 44 | 45 | int 46 | sys_sbrk(void) 47 | { 48 | int addr; 49 | int n; 50 | 51 | if(argint(0, &n) < 0) 52 | return -1; 53 | addr = myproc()->sz; 54 | // if(growproc(n) < 0) 55 | // return -1; 56 | myproc()->sz+=n; 57 | return addr; 58 | } 59 | 60 | int 61 | sys_sleep(void) 62 | { 63 | int n; 64 | uint ticks0; 65 | 66 | if(argint(0, &n) < 0) 67 | return -1; 68 | acquire(&tickslock); 69 | ticks0 = ticks; 70 | while(ticks - ticks0 < n){ 71 | if(myproc()->killed){ 72 | release(&tickslock); 73 | return -1; 74 | } 75 | sleep(&ticks, &tickslock); 76 | } 77 | release(&tickslock); 78 | return 0; 79 | } 80 | 81 | // return how many clock tick interrupts have occurred 82 | // since start. 83 | int 84 | sys_uptime(void) 85 | { 86 | uint xticks; 87 | 88 | acquire(&tickslock); 89 | xticks = ticks; 90 | release(&tickslock); 91 | return xticks; 92 | } 93 | 94 | int 95 | sys_date(void){ 96 | struct rtcdate *r; 97 | if(argptr(0,(char **) &r,sizeof(struct rtcdate))<0) 98 | return -1; 99 | cmostime(r); 100 | return 0; 101 | } 102 | 103 | int 104 | sys_alarm(void){ 105 | int ticks; 106 | void (*handler)(); 107 | if(argint(0,&ticks)<0) 108 | return -1; 109 | if(argptr(1,(char **)&handler,1)<0) 110 | return -1; 111 | myproc()->alarmticks=ticks; 112 | myproc()->handler=handler; 113 | return 0; 114 | } 115 | -------------------------------------------------------------------------------- /code/2: -------------------------------------------------------------------------------- 1 | " 设置字符编码 2 | set fileencoding=utf-8 3 | set fileencodings=utf-8,gb2312,gb18030,latin1 4 | set termencoding=utf-8 5 | set encoding=utf-8 6 | 7 | "搜索高亮 8 | set hlsearch 9 | 10 | " 语法高亮 11 | syntax on 12 | " 深色背景 13 | "color evening 14 | " 检测文件类型 15 | filetype on 16 | " 根据文件类型加载对应的插件 17 | filetype plugin on 18 | 19 | " 显示行号 20 | set number 21 | " 在第64列显示竖线 22 | "set cc=100 23 | " 高亮显示当前行 24 | "set cursorline 25 | 26 | " 设置各种缩进 27 | set tabstop=4 28 | set softtabstop=4 29 | set shiftwidth=4 30 | set autoindent 31 | set smartindent 32 | set cindent 33 | " tab转换为空格 34 | set expandtab 35 | 36 | " 将ESC键映射为两次j键 37 | inoremap jj 38 | 39 | " 自动完成大括号 40 | imap { {}kA 41 | nmap :NERDTree 42 | nmap :exe 'NERDTreeToggle' 43 | let NERDTreeIgnore = ['.*\.o$','.*\.ko$','.*\.gz$','.*/*','*\.d$','.*\.sym$','.*\.img$'] 44 | -------------------------------------------------------------------------------- /code/ioapic.c: -------------------------------------------------------------------------------- 1 | // The I/O APIC manages hardware interrupts for an SMP system. 2 | // http://www.intel.com/design/chipsets/datashts/29056601.pdf 3 | // See also picirq.c. 4 | 5 | #include "types.h" 6 | #include "defs.h" 7 | #include "traps.h" 8 | 9 | #define IOAPIC 0xFEC00000 // Default physical address of IO APIC 10 | 11 | #define REG_ID 0x00 // Register index: ID 12 | #define REG_VER 0x01 // Register index: version 13 | #define REG_TABLE 0x10 // Redirection table base 14 | 15 | // The redirection table starts at REG_TABLE and uses 16 | // two registers to configure each interrupt. 17 | // The first (low) register in a pair contains configuration bits. 18 | // The second (high) register contains a bitmask telling which 19 | // CPUs can serve that interrupt. 20 | #define INT_DISABLED 0x00010000 // Interrupt disabled 21 | #define INT_LEVEL 0x00008000 // Level-triggered (vs edge-) 22 | #define INT_ACTIVELOW 0x00002000 // Active low (vs high) 23 | #define INT_LOGICAL 0x00000800 // Destination is CPU id (vs APIC ID) 24 | 25 | volatile struct ioapic *ioapic; 26 | 27 | // IO APIC MMIO structure: write reg, then read or write data. 28 | struct ioapic { 29 | uint reg; 30 | uint pad[3]; 31 | uint data; 32 | }; 33 | 34 | static uint 35 | ioapicread(int reg) 36 | { 37 | ioapic->reg = reg; 38 | return ioapic->data; 39 | } 40 | 41 | static void 42 | ioapicwrite(int reg, uint data) 43 | { 44 | ioapic->reg = reg; 45 | ioapic->data = data; 46 | } 47 | 48 | void 49 | ioapicinit(void) 50 | { 51 | int i, id, maxintr; 52 | 53 | ioapic = (volatile struct ioapic*)IOAPIC; 54 | maxintr = (ioapicread(REG_VER) >> 16) & 0xFF; 55 | id = ioapicread(REG_ID) >> 24; 56 | if(id != ioapicid) 57 | cprintf("ioapicinit: id isn't equal to ioapicid; not a MP\n"); 58 | 59 | // Mark all interrupts edge-triggered, active high, disabled, 60 | // and not routed to any CPUs. 61 | for(i = 0; i <= maxintr; i++){ 62 | ioapicwrite(REG_TABLE+2*i, INT_DISABLED | (T_IRQ0 + i)); 63 | ioapicwrite(REG_TABLE+2*i+1, 0); 64 | } 65 | } 66 | 67 | void 68 | ioapicenable(int irq, int cpunum) 69 | { 70 | // Mark interrupt edge-triggered, active high, 71 | // enabled, and routed to the given cpunum, 72 | // which happens to be that cpu's APIC ID. 73 | ioapicwrite(REG_TABLE+2*irq, T_IRQ0 + irq); 74 | ioapicwrite(REG_TABLE+2*irq+1, cpunum << 24); 75 | } 76 | -------------------------------------------------------------------------------- /code/mp.h: -------------------------------------------------------------------------------- 1 | // See MultiProcessor Specification Version 1.[14] 2 | 3 | struct mp { // floating pointer 4 | uchar signature[4]; // "_MP_" 5 | void *physaddr; // phys addr of MP config table 6 | uchar length; // 1 7 | uchar specrev; // [14] 8 | uchar checksum; // all bytes must add up to 0 9 | uchar type; // MP system config type 10 | uchar imcrp; 11 | uchar reserved[3]; 12 | }; 13 | 14 | struct mpconf { // configuration table header 15 | uchar signature[4]; // "PCMP" 16 | ushort length; // total table length 17 | uchar version; // [14] 18 | uchar checksum; // all bytes must add up to 0 19 | uchar product[20]; // product id 20 | uint *oemtable; // OEM table pointer 21 | ushort oemlength; // OEM table length 22 | ushort entry; // entry count 23 | uint *lapicaddr; // address of local APIC 24 | ushort xlength; // extended table length 25 | uchar xchecksum; // extended table checksum 26 | uchar reserved; 27 | }; 28 | 29 | struct mpproc { // processor table entry 30 | uchar type; // entry type (0) 31 | uchar apicid; // local APIC id 32 | uchar version; // local APIC verison 33 | uchar flags; // CPU flags 34 | #define MPBOOT 0x02 // This proc is the bootstrap processor. 35 | uchar signature[4]; // CPU signature 36 | uint feature; // feature flags from CPUID instruction 37 | uchar reserved[8]; 38 | }; 39 | 40 | struct mpioapic { // I/O APIC table entry 41 | uchar type; // entry type (2) 42 | uchar apicno; // I/O APIC id 43 | uchar version; // I/O APIC version 44 | uchar flags; // I/O APIC flags 45 | uint *addr; // I/O APIC address 46 | }; 47 | 48 | // Table entry types 49 | #define MPPROC 0x00 // One per processor 50 | #define MPBUS 0x01 // One per bus 51 | #define MPIOAPIC 0x02 // One per I/O APIC 52 | #define MPIOINTR 0x03 // One per bus interrupt source 53 | #define MPLINTR 0x04 // One per system interrupt source 54 | 55 | //PAGEBREAK! 56 | // Blank page. 57 | -------------------------------------------------------------------------------- /code/grep.c: -------------------------------------------------------------------------------- 1 | // Simple grep. Only supports ^ . * $ operators. 2 | 3 | #include "types.h" 4 | #include "stat.h" 5 | #include "user.h" 6 | 7 | char buf[1024]; 8 | int match(char*, char*); 9 | 10 | void 11 | grep(char *pattern, int fd) 12 | { 13 | int n, m; 14 | char *p, *q; 15 | 16 | m = 0; 17 | while((n = read(fd, buf+m, sizeof(buf)-m-1)) > 0){ 18 | m += n; 19 | buf[m] = '\0'; 20 | p = buf; 21 | while((q = strchr(p, '\n')) != 0){ 22 | *q = 0; 23 | if(match(pattern, p)){ 24 | *q = '\n'; 25 | write(1, p, q+1 - p); 26 | } 27 | p = q+1; 28 | } 29 | if(p == buf) 30 | m = 0; 31 | if(m > 0){ 32 | m -= p - buf; 33 | memmove(buf, p, m); 34 | } 35 | } 36 | } 37 | 38 | int 39 | main(int argc, char *argv[]) 40 | { 41 | int fd, i; 42 | char *pattern; 43 | 44 | if(argc <= 1){ 45 | printf(2, "usage: grep pattern [file ...]\n"); 46 | exit(); 47 | } 48 | pattern = argv[1]; 49 | 50 | if(argc <= 2){ 51 | grep(pattern, 0); 52 | exit(); 53 | } 54 | 55 | for(i = 2; i < argc; i++){ 56 | if((fd = open(argv[i], 0)) < 0){ 57 | printf(1, "grep: cannot open %s\n", argv[i]); 58 | exit(); 59 | } 60 | grep(pattern, fd); 61 | close(fd); 62 | } 63 | exit(); 64 | } 65 | 66 | // Regexp matcher from Kernighan & Pike, 67 | // The Practice of Programming, Chapter 9. 68 | 69 | int matchhere(char*, char*); 70 | int matchstar(int, char*, char*); 71 | 72 | int 73 | match(char *re, char *text) 74 | { 75 | if(re[0] == '^') 76 | return matchhere(re+1, text); 77 | do{ // must look at empty string 78 | if(matchhere(re, text)) 79 | return 1; 80 | }while(*text++ != '\0'); 81 | return 0; 82 | } 83 | 84 | // matchhere: search for re at beginning of text 85 | int matchhere(char *re, char *text) 86 | { 87 | if(re[0] == '\0') 88 | return 1; 89 | if(re[1] == '*') 90 | return matchstar(re[0], re+2, text); 91 | if(re[0] == '$' && re[1] == '\0') 92 | return *text == '\0'; 93 | if(*text!='\0' && (re[0]=='.' || re[0]==*text)) 94 | return matchhere(re+1, text+1); 95 | return 0; 96 | } 97 | 98 | // matchstar: search for c*re at beginning of text 99 | int matchstar(int c, char *re, char *text) 100 | { 101 | do{ // a * matches zero or more instances 102 | if(matchhere(re, text)) 103 | return 1; 104 | }while(*text!='\0' && (*text++==c || c=='.')); 105 | return 0; 106 | } 107 | 108 | -------------------------------------------------------------------------------- /code/kalloc.c: -------------------------------------------------------------------------------- 1 | // Physical memory allocator, intended to allocate 2 | // memory for user processes, kernel stacks, page table pages, 3 | // and pipe buffers. Allocates 4096-byte pages. 4 | 5 | #include "types.h" 6 | #include "defs.h" 7 | #include "param.h" 8 | #include "memlayout.h" 9 | #include "mmu.h" 10 | #include "spinlock.h" 11 | 12 | void freerange(void *vstart, void *vend); 13 | extern char end[]; // first address after kernel loaded from ELF file 14 | // defined by the kernel linker script in kernel.ld 15 | 16 | struct run { 17 | struct run *next; 18 | }; 19 | 20 | struct { 21 | struct spinlock lock; 22 | int use_lock; 23 | struct run *freelist; 24 | } kmem; 25 | 26 | // Initialization happens in two phases. 27 | // 1. main() calls kinit1() while still using entrypgdir to place just 28 | // the pages mapped by entrypgdir on free list. 29 | // 2. main() calls kinit2() with the rest of the physical pages 30 | // after installing a full page table that maps them on all cores. 31 | void 32 | kinit1(void *vstart, void *vend) 33 | { 34 | initlock(&kmem.lock, "kmem"); 35 | kmem.use_lock = 0; 36 | freerange(vstart, vend); 37 | } 38 | 39 | void 40 | kinit2(void *vstart, void *vend) 41 | { 42 | freerange(vstart, vend); 43 | kmem.use_lock = 1; 44 | } 45 | 46 | void 47 | freerange(void *vstart, void *vend) 48 | { 49 | char *p; 50 | p = (char*)PGROUNDUP((uint)vstart); 51 | for(; p + PGSIZE <= (char*)vend; p += PGSIZE) 52 | kfree(p); 53 | } 54 | //PAGEBREAK: 21 55 | // Free the page of physical memory pointed at by v, 56 | // which normally should have been returned by a 57 | // call to kalloc(). (The exception is when 58 | // initializing the allocator; see kinit above.) 59 | void 60 | kfree(char *v) 61 | { 62 | struct run *r; 63 | 64 | if((uint)v % PGSIZE || v < end || V2P(v) >= PHYSTOP) 65 | panic("kfree"); 66 | 67 | // Fill with junk to catch dangling refs. 68 | memset(v, 1, PGSIZE); 69 | 70 | if(kmem.use_lock) 71 | acquire(&kmem.lock); 72 | r = (struct run*)v; 73 | r->next = kmem.freelist; 74 | kmem.freelist = r; 75 | if(kmem.use_lock) 76 | release(&kmem.lock); 77 | } 78 | 79 | // Allocate one 4096-byte page of physical memory. 80 | // Returns a pointer that the kernel can use. 81 | // Returns 0 if the memory cannot be allocated. 82 | char* 83 | kalloc(void) 84 | { 85 | struct run *r; 86 | 87 | if(kmem.use_lock) 88 | acquire(&kmem.lock); 89 | r = kmem.freelist; 90 | if(r) 91 | kmem.freelist = r->next; 92 | if(kmem.use_lock) 93 | release(&kmem.lock); 94 | return (char*)r; 95 | } 96 | 97 | -------------------------------------------------------------------------------- /code/proc.h: -------------------------------------------------------------------------------- 1 | // Per-CPU state 2 | struct cpu { 3 | uchar apicid; // Local APIC ID 4 | struct context *scheduler; // swtch() here to enter scheduler 5 | struct taskstate ts; // Used by x86 to find stack for interrupt 6 | struct segdesc gdt[NSEGS]; // x86 global descriptor table 7 | volatile uint started; // Has the CPU started? 8 | int ncli; // Depth of pushcli nesting. 9 | int intena; // Were interrupts enabled before pushcli? 10 | struct proc *proc; // The process running on this cpu or null 11 | }; 12 | 13 | extern struct cpu cpus[NCPU]; 14 | extern int ncpu; 15 | 16 | //PAGEBREAK: 17 17 | // Saved registers for kernel context switches. 18 | // Don't need to save all the segment registers (%cs, etc), 19 | // because they are constant across kernel contexts. 20 | // Don't need to save %eax, %ecx, %edx, because the 21 | // x86 convention is that the caller has saved them. 22 | // Contexts are stored at the bottom of the stack they 23 | // describe; the stack pointer is the address of the context. 24 | // The layout of the context matches the layout of the stack in swtch.S 25 | // at the "Switch stacks" comment. Switch doesn't save eip explicitly, 26 | // but it is on the stack and allocproc() manipulates it. 27 | struct context { 28 | uint edi; 29 | uint esi; 30 | uint ebx; 31 | uint ebp; 32 | uint eip; 33 | }; 34 | 35 | enum procstate { UNUSED, EMBRYO, SLEEPING, RUNNABLE, RUNNING, ZOMBIE }; 36 | 37 | // Per-process state 38 | struct proc { 39 | uint sz; // Size of process memory (bytes) 40 | pde_t* pgdir; // Page table 41 | char *kstack; // Bottom of kernel stack for this process 42 | enum procstate state; // Process state 43 | int pid; // Process ID 44 | struct proc *parent; // Parent process 45 | struct trapframe *tf; // Trap frame for current syscall 46 | struct context *context; // swtch() here to run process 47 | void *chan; // If non-zero, sleeping on chan 48 | int killed; // If non-zero, have been killed 49 | struct file *ofile[NOFILE]; // Open files 50 | struct inode *cwd; // Current directory 51 | char name[16]; // Process name (debugging) 52 | //homework 53 | int alarmticks; 54 | void *handler; 55 | int elapsedticks; 56 | }; 57 | 58 | // Process memory is laid out contiguously, low addresses first: 59 | // text 60 | // original data and bss 61 | // fixed-size stack 62 | // expandable heap 63 | -------------------------------------------------------------------------------- /code/bootmain.c: -------------------------------------------------------------------------------- 1 | // Boot loader. 2 | // 3 | // Part of the boot block, along with bootasm.S, which calls bootmain(). 4 | // bootasm.S has put the processor into protected 32-bit mode. 5 | // bootmain() loads an ELF kernel image from the disk starting at 6 | // sector 1 and then jumps to the kernel entry routine. 7 | 8 | #include "types.h" 9 | #include "elf.h" 10 | #include "x86.h" 11 | #include "memlayout.h" 12 | 13 | #define SECTSIZE 512 14 | 15 | void readseg(uchar*, uint, uint); 16 | 17 | void 18 | bootmain(void) 19 | { 20 | struct elfhdr *elf; 21 | struct proghdr *ph, *eph; 22 | void (*entry)(void); 23 | uchar* pa; 24 | 25 | elf = (struct elfhdr*)0x10000; // scratch space 26 | 27 | // Read 1st page off disk 28 | readseg((uchar*)elf, 4096, 0); 29 | 30 | // Is this an ELF executable? 31 | if(elf->magic != ELF_MAGIC) 32 | return; // let bootasm.S handle error 33 | 34 | // Load each program segment (ignores ph flags). 35 | ph = (struct proghdr*)((uchar*)elf + elf->phoff); 36 | eph = ph + elf->phnum; 37 | for(; ph < eph; ph++){ 38 | pa = (uchar*)ph->paddr; 39 | readseg(pa, ph->filesz, ph->off); 40 | if(ph->memsz > ph->filesz) 41 | stosb(pa + ph->filesz, 0, ph->memsz - ph->filesz); 42 | } 43 | 44 | // Call the entry point from the ELF header. 45 | // Does not return! 46 | entry = (void(*)(void))(elf->entry); 47 | entry(); 48 | } 49 | 50 | void 51 | waitdisk(void) 52 | { 53 | // Wait for disk ready. 54 | while((inb(0x1F7) & 0xC0) != 0x40) 55 | ; 56 | } 57 | 58 | // Read a single sector at offset into dst. 59 | void 60 | readsect(void *dst, uint offset) 61 | { 62 | // Issue command. 63 | waitdisk(); 64 | outb(0x1F2, 1); // count = 1 65 | outb(0x1F3, offset); 66 | outb(0x1F4, offset >> 8); 67 | outb(0x1F5, offset >> 16); 68 | outb(0x1F6, (offset >> 24) | 0xE0); 69 | outb(0x1F7, 0x20); // cmd 0x20 - read sectors 70 | 71 | // Read data. 72 | waitdisk(); 73 | insl(0x1F0, dst, SECTSIZE/4); 74 | } 75 | 76 | // Read 'count' bytes at 'offset' from kernel into physical address 'pa'. 77 | // Might copy more than asked. 78 | void 79 | readseg(uchar* pa, uint count, uint offset) 80 | { 81 | uchar* epa; 82 | 83 | epa = pa + count; 84 | 85 | // Round down to sector boundary. 86 | pa -= offset % SECTSIZE; 87 | 88 | // Translate from bytes to sectors; kernel starts at sector 1. 89 | offset = (offset / SECTSIZE) + 1; 90 | 91 | // If this is too slow, we could read lots of sectors at a time. 92 | // We'd write more to memory than asked, but it doesn't matter -- 93 | // we load in increasing order. 94 | for(; pa < epa; pa += SECTSIZE, offset++) 95 | readsect(pa, offset); 96 | } 97 | -------------------------------------------------------------------------------- /code/sleep1.p: -------------------------------------------------------------------------------- 1 | /* 2 | This file defines a Promela model for xv6's 3 | acquire, release, sleep, and wakeup, along with 4 | a model of a simple producer/consumer queue. 5 | 6 | To run: 7 | spinp sleep1.p 8 | 9 | (You may need to install Spin, available at http://spinroot.com/.) 10 | 11 | After a successful run spin prints something like: 12 | 13 | unreached in proctype consumer 14 | (0 of 37 states) 15 | unreached in proctype producer 16 | (0 of 23 states) 17 | 18 | After an unsuccessful run, the spinp script prints 19 | an execution trace that causes a deadlock. 20 | 21 | The safe body of producer reads: 22 | 23 | acquire(lk); 24 | x = value; value = x + 1; x = 0; 25 | wakeup(0); 26 | release(lk); 27 | i = i + 1; 28 | 29 | If this is changed to: 30 | 31 | x = value; value = x + 1; x = 0; 32 | acquire(lk); 33 | wakeup(0); 34 | release(lk); 35 | i = i + 1; 36 | 37 | then a deadlock can happen, because the non-atomic 38 | increment of value conflicts with the non-atomic 39 | decrement in consumer, causing value to have a bad value. 40 | Try this. 41 | 42 | If it is changed to: 43 | 44 | acquire(lk); 45 | x = value; value = x + 1; x = 0; 46 | release(lk); 47 | wakeup(0); 48 | i = i + 1; 49 | 50 | then nothing bad happens: it is okay to wakeup after release 51 | instead of before, although it seems morally wrong. 52 | */ 53 | 54 | #define ITER 4 55 | #define N 2 56 | 57 | bit lk; 58 | byte value; 59 | bit sleeping[N]; 60 | 61 | inline acquire(x) 62 | { 63 | atomic { x == 0; x = 1 } 64 | } 65 | 66 | inline release(x) 67 | { 68 | assert x==1; 69 | x = 0 70 | } 71 | 72 | inline sleep(cond, lk) 73 | { 74 | assert !sleeping[_pid]; 75 | if 76 | :: cond -> 77 | skip 78 | :: else -> 79 | atomic { release(lk); sleeping[_pid] = 1 }; 80 | sleeping[_pid] == 0; 81 | acquire(lk) 82 | fi 83 | } 84 | 85 | inline wakeup() 86 | { 87 | w = 0; 88 | do 89 | :: w < N -> 90 | sleeping[w] = 0; 91 | w = w + 1 92 | :: else -> 93 | break 94 | od 95 | } 96 | 97 | active[N] proctype consumer() 98 | { 99 | byte i, x; 100 | 101 | i = 0; 102 | do 103 | :: i < ITER -> 104 | acquire(lk); 105 | sleep(value > 0, lk); 106 | x = value; value = x - 1; x = 0; 107 | release(lk); 108 | i = i + 1; 109 | :: else -> 110 | break 111 | od; 112 | i = 0; 113 | skip 114 | } 115 | 116 | active[N] proctype producer() 117 | { 118 | byte i, x, w; 119 | 120 | i = 0; 121 | do 122 | :: i < ITER -> 123 | acquire(lk); 124 | x = value; value = x + 1; x = 0; 125 | release(lk); 126 | wakeup(); 127 | i = i + 1; 128 | :: else -> 129 | break 130 | od; 131 | i = 0; 132 | skip 133 | } 134 | 135 | -------------------------------------------------------------------------------- /code/runoff1: -------------------------------------------------------------------------------- 1 | #!/usr/bin/perl 2 | 3 | $n = 0; 4 | $v = 0; 5 | if($ARGV[0] eq "-v") { 6 | $v = 1; 7 | shift @ARGV; 8 | } 9 | if($ARGV[0] eq "-n") { 10 | $n = $ARGV[1]; 11 | shift @ARGV; 12 | shift @ARGV; 13 | } 14 | $n = int(($n+49)/50)*50 - 1; 15 | 16 | $file = $ARGV[0]; 17 | @lines = <>; 18 | $linenum = 0; 19 | foreach (@lines) { 20 | $linenum++; 21 | chomp; 22 | s/\s+$//; 23 | if(length() >= 75){ 24 | print STDERR "$file:$linenum: line too long\n"; 25 | } 26 | } 27 | @outlines = (); 28 | $nextout = 0; 29 | 30 | for($i=0; $i<@lines; ){ 31 | # Skip leading blank lines. 32 | $i++ while $i<@lines && $lines[$i] =~ /^$/; 33 | last if $i>=@lines; 34 | 35 | # If the rest of the file fits, use the whole thing. 36 | if(@lines <= $i+50 && !grep { /PAGEBREAK/ } @lines){ 37 | $breakbefore = @lines; 38 | }else{ 39 | # Find a good next page break; 40 | # Hope for end of function. 41 | # but settle for a blank line (but not first blank line 42 | # in function, which comes after variable declarations). 43 | $breakbefore = $i; 44 | $lastblank = $i; 45 | $sawbrace = 0; 46 | $breaksize = 15; # 15 lines to get to function 47 | for($j=$i; $j<$i+50 && $j < @lines; $j++){ 48 | if($lines[$j] =~ /PAGEBREAK!/){ 49 | $lines[$j] = ""; 50 | $breakbefore = $j; 51 | $breaksize = 100; 52 | last; 53 | } 54 | if($lines[$j] =~ /PAGEBREAK:\s*([0-9]+)/){ 55 | $breaksize = $1; 56 | $breakbefore = $j; 57 | $lines[$j] = ""; 58 | } 59 | if($lines[$j] =~ /^};?$/){ 60 | $breakbefore = $j+1; 61 | $breaksize = 15; 62 | } 63 | if($lines[$j] =~ /^{$/){ 64 | $sawbrace = 1; 65 | } 66 | if($lines[$j] =~ /^$/){ 67 | if($sawbrace){ 68 | $sawbrace = 0; 69 | }else{ 70 | $lastblank = $j; 71 | } 72 | } 73 | } 74 | if($j<@lines && $lines[$j] =~ /^$/){ 75 | $lastblank = $j; 76 | } 77 | 78 | # If we are not putting enough on a page, try a blank line. 79 | if($breakbefore - $i < 50 - $breaksize && $lastblank > $breakbefore && $lastblank >= $i+50 - 5){ 80 | if($v){ 81 | print STDERR "breakbefore $breakbefore i $i breaksize $breaksize\n"; 82 | } 83 | $breakbefore = $lastblank; 84 | $breaksize = 5; # only 5 lines to get to blank line 85 | } 86 | 87 | # If we are not putting enough on a page, force a full page. 88 | if($breakbefore - $i < 50 - $breaksize && $breakbefore != @lines){ 89 | $breakbefore = $i + 50; 90 | $breakbefore = @lines if @lines < $breakbefore; 91 | } 92 | 93 | if($breakbefore < $i+2){ 94 | $breakbefore = $i+2; 95 | } 96 | } 97 | 98 | # Emit the page. 99 | $i50 = $i + 50; 100 | for(; $i<$breakbefore; $i++){ 101 | printf "%04d %s\n", ++$n, $lines[$i]; 102 | } 103 | 104 | # Finish page 105 | for($j=$i; $j<$i50; $j++){ 106 | printf "%04d \n", ++$n; 107 | } 108 | } 109 | -------------------------------------------------------------------------------- /code/pipe.c: -------------------------------------------------------------------------------- 1 | #include "types.h" 2 | #include "defs.h" 3 | #include "param.h" 4 | #include "mmu.h" 5 | #include "proc.h" 6 | #include "fs.h" 7 | #include "spinlock.h" 8 | #include "sleeplock.h" 9 | #include "file.h" 10 | 11 | #define PIPESIZE 512 12 | 13 | struct pipe { 14 | struct spinlock lock; 15 | char data[PIPESIZE]; 16 | uint nread; // number of bytes read 17 | uint nwrite; // number of bytes written 18 | int readopen; // read fd is still open 19 | int writeopen; // write fd is still open 20 | }; 21 | 22 | int 23 | pipealloc(struct file **f0, struct file **f1) 24 | { 25 | struct pipe *p; 26 | 27 | p = 0; 28 | *f0 = *f1 = 0; 29 | if((*f0 = filealloc()) == 0 || (*f1 = filealloc()) == 0) 30 | goto bad; 31 | if((p = (struct pipe*)kalloc()) == 0) 32 | goto bad; 33 | p->readopen = 1; 34 | p->writeopen = 1; 35 | p->nwrite = 0; 36 | p->nread = 0; 37 | initlock(&p->lock, "pipe"); 38 | (*f0)->type = FD_PIPE; 39 | (*f0)->readable = 1; 40 | (*f0)->writable = 0; 41 | (*f0)->pipe = p; 42 | (*f1)->type = FD_PIPE; 43 | (*f1)->readable = 0; 44 | (*f1)->writable = 1; 45 | (*f1)->pipe = p; 46 | return 0; 47 | 48 | //PAGEBREAK: 20 49 | bad: 50 | if(p) 51 | kfree((char*)p); 52 | if(*f0) 53 | fileclose(*f0); 54 | if(*f1) 55 | fileclose(*f1); 56 | return -1; 57 | } 58 | 59 | void 60 | pipeclose(struct pipe *p, int writable) 61 | { 62 | acquire(&p->lock); 63 | if(writable){ 64 | p->writeopen = 0; 65 | wakeup(&p->nread); 66 | } else { 67 | p->readopen = 0; 68 | wakeup(&p->nwrite); 69 | } 70 | if(p->readopen == 0 && p->writeopen == 0){ 71 | release(&p->lock); 72 | kfree((char*)p); 73 | } else 74 | release(&p->lock); 75 | } 76 | 77 | //PAGEBREAK: 40 78 | int 79 | pipewrite(struct pipe *p, char *addr, int n) 80 | { 81 | int i; 82 | 83 | acquire(&p->lock); 84 | for(i = 0; i < n; i++){ 85 | while(p->nwrite == p->nread + PIPESIZE){ //DOC: pipewrite-full 86 | if(p->readopen == 0 || myproc()->killed){ 87 | release(&p->lock); 88 | return -1; 89 | } 90 | wakeup(&p->nread); 91 | sleep(&p->nwrite, &p->lock); //DOC: pipewrite-sleep 92 | } 93 | p->data[p->nwrite++ % PIPESIZE] = addr[i]; 94 | } 95 | wakeup(&p->nread); //DOC: pipewrite-wakeup1 96 | release(&p->lock); 97 | return n; 98 | } 99 | 100 | int 101 | piperead(struct pipe *p, char *addr, int n) 102 | { 103 | int i; 104 | 105 | acquire(&p->lock); 106 | while(p->nread == p->nwrite && p->writeopen){ //DOC: pipe-empty 107 | if(myproc()->killed){ 108 | release(&p->lock); 109 | return -1; 110 | } 111 | sleep(&p->nread, &p->lock); //DOC: piperead-sleep 112 | } 113 | for(i = 0; i < n; i++){ //DOC: piperead-copy 114 | if(p->nread == p->nwrite) 115 | break; 116 | addr[i] = p->data[p->nread++ % PIPESIZE]; 117 | } 118 | wakeup(&p->nwrite); //DOC: piperead-wakeup 119 | release(&p->lock); 120 | return i; 121 | } 122 | -------------------------------------------------------------------------------- /code/runoff.spec: -------------------------------------------------------------------------------- 1 | # Is sheet 01 (after the TOC) a left sheet or a right sheet? 2 | sheet1: left 3 | 4 | # "left" and "right" specify which page of a two-page spread a file 5 | # must start on. "left" means that a file must start on the first of 6 | # the two pages. "right" means it must start on the second of the two 7 | # pages. The file may start in either column. 8 | # 9 | # "even" and "odd" specify which column a file must start on. "even" 10 | # means it must start in the left of the two columns (00). "odd" means it 11 | # must start in the right of the two columns (50). 12 | # 13 | # You'd think these would be the other way around. 14 | 15 | # types.h either 16 | # param.h either 17 | # defs.h either 18 | # x86.h either 19 | # asm.h either 20 | # mmu.h either 21 | # elf.h either 22 | # mp.h either 23 | 24 | even: entry.S # mild preference 25 | even: entryother.S # mild preference 26 | even: main.c 27 | # mp.c don't care at all 28 | # even: initcode.S 29 | # odd: init.c 30 | 31 | left: spinlock.h 32 | even: spinlock.h 33 | 34 | # This gets struct proc and allocproc on the same spread 35 | left: proc.h 36 | even: proc.h 37 | 38 | # goal is to have two action-packed 2-page spreads, 39 | # one with 40 | # userinit growproc fork exit wait 41 | # and another with 42 | # scheduler sched yield forkret sleep wakeup1 wakeup 43 | right: proc.c # VERY important 44 | even: proc.c # VERY important 45 | 46 | # A few more action packed spreads 47 | # page table creation and process loading 48 | # walkpgdir mappages setupkvm switch[ku]vm inituvm (loaduvm) 49 | # process memory management 50 | # allocuvm deallocuvm freevm 51 | left: vm.c 52 | 53 | even: kalloc.c # mild preference 54 | 55 | # syscall.h either 56 | # trapasm.S either 57 | # traps.h either 58 | # even: trap.c 59 | # vectors.pl either 60 | # syscall.c either 61 | # sysproc.c either 62 | 63 | # buf.h either 64 | # dev.h either 65 | # fcntl.h either 66 | # stat.h either 67 | # file.h either 68 | # fs.h either 69 | # fsvar.h either 70 | # left: ide.c # mild preference 71 | even: ide.c 72 | # odd: bio.c 73 | 74 | # log.c fits nicely in a spread 75 | even: log.c 76 | left: log.c 77 | 78 | # with fs.c starting on 2nd column of a left page, we get these 2-page spreads: 79 | # ialloc iupdate iget idup ilock iunlock iput iunlockput 80 | # bmap itrunc stati readi writei 81 | # namecmp dirlookup dirlink skipelem namex namei 82 | # fileinit filealloc filedup fileclose filestat fileread filewrite 83 | # starting on 2nd column of a right page is not terrible either 84 | odd: fs.c # VERY important 85 | left: fs.c # mild preference 86 | # file.c either 87 | # exec.c either 88 | # sysfile.c either 89 | 90 | # Mild preference, but makes spreads of mp.c, lapic.c, and ioapic.c+picirq.c 91 | even: mp.c 92 | left: mp.c 93 | 94 | # even: pipe.c # mild preference 95 | # string.c either 96 | # left: kbd.h # mild preference 97 | even: kbd.h 98 | even: console.c 99 | odd: sh.c 100 | 101 | even: bootasm.S # mild preference 102 | even: bootmain.c # mild preference 103 | -------------------------------------------------------------------------------- /code/entryother.S: -------------------------------------------------------------------------------- 1 | #include "asm.h" 2 | #include "memlayout.h" 3 | #include "mmu.h" 4 | 5 | # Each non-boot CPU ("AP") is started up in response to a STARTUP 6 | # IPI from the boot CPU. Section B.4.2 of the Multi-Processor 7 | # Specification says that the AP will start in real mode with CS:IP 8 | # set to XY00:0000, where XY is an 8-bit value sent with the 9 | # STARTUP. Thus this code must start at a 4096-byte boundary. 10 | # 11 | # Because this code sets DS to zero, it must sit 12 | # at an address in the low 2^16 bytes. 13 | # 14 | # Startothers (in main.c) sends the STARTUPs one at a time. 15 | # It copies this code (start) at 0x7000. It puts the address of 16 | # a newly allocated per-core stack in start-4,the address of the 17 | # place to jump to (mpenter) in start-8, and the physical address 18 | # of entrypgdir in start-12. 19 | # 20 | # This code combines elements of bootasm.S and entry.S. 21 | 22 | .code16 23 | .globl start 24 | start: 25 | cli 26 | 27 | # Zero data segment registers DS, ES, and SS. 28 | xorw %ax,%ax 29 | movw %ax,%ds 30 | movw %ax,%es 31 | movw %ax,%ss 32 | 33 | # Switch from real to protected mode. Use a bootstrap GDT that makes 34 | # virtual addresses map directly to physical addresses so that the 35 | # effective memory map doesn't change during the transition. 36 | lgdt gdtdesc 37 | movl %cr0, %eax 38 | orl $CR0_PE, %eax 39 | movl %eax, %cr0 40 | 41 | # Complete the transition to 32-bit protected mode by using a long jmp 42 | # to reload %cs and %eip. The segment descriptors are set up with no 43 | # translation, so that the mapping is still the identity mapping. 44 | ljmpl $(SEG_KCODE<<3), $(start32) 45 | 46 | //PAGEBREAK! 47 | .code32 # Tell assembler to generate 32-bit code now. 48 | start32: 49 | # Set up the protected-mode data segment registers 50 | movw $(SEG_KDATA<<3), %ax # Our data segment selector 51 | movw %ax, %ds # -> DS: Data Segment 52 | movw %ax, %es # -> ES: Extra Segment 53 | movw %ax, %ss # -> SS: Stack Segment 54 | movw $0, %ax # Zero segments not ready for use 55 | movw %ax, %fs # -> FS 56 | movw %ax, %gs # -> GS 57 | 58 | # Turn on page size extension for 4Mbyte pages 59 | movl %cr4, %eax 60 | orl $(CR4_PSE), %eax 61 | movl %eax, %cr4 62 | # Use entrypgdir as our initial page table 63 | movl (start-12), %eax 64 | movl %eax, %cr3 65 | # Turn on paging. 66 | movl %cr0, %eax 67 | orl $(CR0_PE|CR0_PG|CR0_WP), %eax 68 | movl %eax, %cr0 69 | 70 | # Switch to the stack allocated by startothers() 71 | movl (start-4), %esp 72 | # Call mpenter() 73 | call *(start-8) 74 | 75 | movw $0x8a00, %ax 76 | movw %ax, %dx 77 | outw %ax, %dx 78 | movw $0x8ae0, %ax 79 | outw %ax, %dx 80 | spin: 81 | jmp spin 82 | 83 | .p2align 2 84 | gdt: 85 | SEG_NULLASM 86 | SEG_ASM(STA_X|STA_R, 0, 0xffffffff) 87 | SEG_ASM(STA_W, 0, 0xffffffff) 88 | 89 | 90 | gdtdesc: 91 | .word (gdtdesc - gdt - 1) 92 | .long gdt 93 | 94 | -------------------------------------------------------------------------------- /code/exec.c: -------------------------------------------------------------------------------- 1 | #include "types.h" 2 | #include "param.h" 3 | #include "memlayout.h" 4 | #include "mmu.h" 5 | #include "proc.h" 6 | #include "defs.h" 7 | #include "x86.h" 8 | #include "elf.h" 9 | 10 | int 11 | exec(char *path, char **argv) 12 | { 13 | char *s, *last; 14 | int i, off; 15 | uint argc, sz, sp, ustack[3+MAXARG+1]; 16 | struct elfhdr elf; 17 | struct inode *ip; 18 | struct proghdr ph; 19 | pde_t *pgdir, *oldpgdir; 20 | struct proc *curproc = myproc(); 21 | 22 | begin_op(); 23 | 24 | if((ip = namei(path)) == 0){ 25 | end_op(); 26 | cprintf("exec: fail\n"); 27 | return -1; 28 | } 29 | ilock(ip); 30 | pgdir = 0; 31 | 32 | // Check ELF header 33 | if(readi(ip, (char*)&elf, 0, sizeof(elf)) != sizeof(elf)) 34 | goto bad; 35 | if(elf.magic != ELF_MAGIC) 36 | goto bad; 37 | 38 | if((pgdir = setupkvm()) == 0) 39 | goto bad; 40 | 41 | // Load program into memory. 42 | sz = 0; 43 | for(i=0, off=elf.phoff; i= MAXARG) 74 | goto bad; 75 | sp = (sp - (strlen(argv[argc]) + 1)) & ~3; 76 | if(copyout(pgdir, sp, argv[argc], strlen(argv[argc]) + 1) < 0) 77 | goto bad; 78 | ustack[3+argc] = sp; 79 | } 80 | ustack[3+argc] = 0; 81 | 82 | ustack[0] = 0xffffffff; // fake return PC 83 | ustack[1] = argc; 84 | ustack[2] = sp - (argc+1)*4; // argv pointer 85 | 86 | sp -= (3+argc+1) * 4; 87 | if(copyout(pgdir, sp, ustack, (3+argc+1)*4) < 0) 88 | goto bad; 89 | 90 | // Save program name for debugging. 91 | for(last=s=path; *s; s++) 92 | if(*s == '/') 93 | last = s+1; 94 | safestrcpy(curproc->name, last, sizeof(curproc->name)); 95 | 96 | // Commit to the user image. 97 | oldpgdir = curproc->pgdir; 98 | curproc->pgdir = pgdir; 99 | curproc->sz = sz; 100 | curproc->tf->eip = elf.entry; // main 101 | curproc->tf->esp = sp; 102 | switchuvm(curproc); 103 | freevm(oldpgdir); 104 | return 0; 105 | 106 | bad: 107 | if(pgdir) 108 | freevm(pgdir); 109 | if(ip){ 110 | iunlockput(ip); 111 | end_op(); 112 | } 113 | return -1; 114 | } 115 | -------------------------------------------------------------------------------- /code/bootasm.S: -------------------------------------------------------------------------------- 1 | #include "asm.h" 2 | #include "memlayout.h" 3 | #include "mmu.h" 4 | 5 | # Start the first CPU: switch to 32-bit protected mode, jump into C. 6 | # The BIOS loads this code from the first sector of the hard disk into 7 | # memory at physical address 0x7c00 and starts executing in real mode 8 | # with %cs=0 %ip=7c00. 9 | 10 | .code16 # Assemble for 16-bit mode 11 | .globl start 12 | start: 13 | cli # BIOS enabled interrupts; disable 14 | 15 | # Zero data segment registers DS, ES, and SS. 16 | xorw %ax,%ax # Set %ax to zero 17 | movw %ax,%ds # -> Data Segment 18 | movw %ax,%es # -> Extra Segment 19 | movw %ax,%ss # -> Stack Segment 20 | 21 | # Physical address line A20 is tied to zero so that the first PCs 22 | # with 2 MB would run software that assumed 1 MB. Undo that. 23 | seta20.1: 24 | inb $0x64,%al # Wait for not busy 25 | testb $0x2,%al 26 | jnz seta20.1 27 | 28 | movb $0xd1,%al # 0xd1 -> port 0x64 29 | outb %al,$0x64 30 | 31 | seta20.2: 32 | inb $0x64,%al # Wait for not busy 33 | testb $0x2,%al 34 | jnz seta20.2 35 | 36 | movb $0xdf,%al # 0xdf -> port 0x60 37 | outb %al,$0x60 38 | 39 | # Switch from real to protected mode. Use a bootstrap GDT that makes 40 | # virtual addresses map directly to physical addresses so that the 41 | # effective memory map doesn't change during the transition. 42 | lgdt gdtdesc 43 | movl %cr0, %eax 44 | orl $CR0_PE, %eax 45 | movl %eax, %cr0 46 | 47 | //PAGEBREAK! 48 | # Complete the transition to 32-bit protected mode by using a long jmp 49 | # to reload %cs and %eip. The segment descriptors are set up with no 50 | # translation, so that the mapping is still the identity mapping. 51 | ljmp $(SEG_KCODE<<3), $start32 52 | 53 | .code32 # Tell assembler to generate 32-bit code now. 54 | start32: 55 | # Set up the protected-mode data segment registers 56 | movw $(SEG_KDATA<<3), %ax # Our data segment selector 57 | movw %ax, %ds # -> DS: Data Segment 58 | movw %ax, %es # -> ES: Extra Segment 59 | movw %ax, %ss # -> SS: Stack Segment 60 | movw $0, %ax # Zero segments not ready for use 61 | movw %ax, %fs # -> FS 62 | movw %ax, %gs # -> GS 63 | 64 | # Set up the stack pointer and call into C. 65 | movl $start, %esp 66 | call bootmain 67 | 68 | # If bootmain returns (it shouldn't), trigger a Bochs 69 | # breakpoint if running under Bochs, then loop. 70 | movw $0x8a00, %ax # 0x8a00 -> port 0x8a00 71 | movw %ax, %dx 72 | outw %ax, %dx 73 | movw $0x8ae0, %ax # 0x8ae0 -> port 0x8a00 74 | outw %ax, %dx 75 | spin: 76 | jmp spin 77 | 78 | # Bootstrap GDT 79 | .p2align 2 # force 4 byte alignment 80 | gdt: 81 | SEG_NULLASM # null seg 82 | SEG_ASM(STA_X|STA_R, 0x0, 0xffffffff) # code seg 83 | SEG_ASM(STA_W, 0x0, 0xffffffff) # data seg 84 | 85 | gdtdesc: 86 | .word (gdtdesc - gdt - 1) # sizeof(gdt) - 1 87 | .long gdt # address gdt 88 | 89 | -------------------------------------------------------------------------------- /code/uthread.c: -------------------------------------------------------------------------------- 1 | #include "types.h" 2 | #include "stat.h" 3 | #include "user.h" 4 | 5 | /* Possible states of a thread; */ 6 | #define FREE 0x0 7 | #define RUNNING 0x1 8 | #define RUNNABLE 0x2 9 | 10 | #define STACK_SIZE 8192 11 | #define MAX_THREAD 4 12 | 13 | typedef struct thread thread_t, *thread_p; 14 | typedef struct mutex mutex_t, *mutex_p; 15 | 16 | struct thread { 17 | int sp; /* saved stack pointer */ 18 | char stack[STACK_SIZE]; /* the thread's stack */ 19 | int state; /* FREE, RUNNING, RUNNABLE */ 20 | }; 21 | static thread_t all_thread[MAX_THREAD]; 22 | thread_p current_thread; 23 | thread_p next_thread; 24 | extern void thread_switch(void); 25 | 26 | void 27 | thread_init(void) 28 | { 29 | // main() is thread 0, which will make the first invocation to 30 | // thread_schedule(). it needs a stack so that the first thread_switch() can 31 | // save thread 0's state. thread_schedule() won't run the main thread ever 32 | // again, because its state is set to RUNNING, and thread_schedule() selects 33 | // a RUNNABLE thread. 34 | current_thread = &all_thread[0]; 35 | current_thread->state = RUNNING; 36 | } 37 | 38 | static void 39 | thread_schedule(void) 40 | { 41 | thread_p t; 42 | 43 | /* Find another runnable thread. */ 44 | next_thread = 0; 45 | for (t = all_thread; t < all_thread + MAX_THREAD; t++) { 46 | if (t->state == RUNNABLE && t != current_thread) { 47 | next_thread = t; 48 | break; 49 | } 50 | } 51 | 52 | if (t >= all_thread + MAX_THREAD && current_thread->state == RUNNABLE) { 53 | /* The current thread is the only runnable thread; run it. */ 54 | next_thread = current_thread; 55 | } 56 | 57 | if (next_thread == 0) { 58 | printf(2, "thread_schedule: no runnable threads\n"); 59 | exit(); 60 | } 61 | 62 | if (current_thread != next_thread) { /* switch threads? */ 63 | next_thread->state = RUNNING; 64 | thread_switch(); 65 | } else 66 | next_thread = 0; 67 | } 68 | 69 | void 70 | thread_create_my(void (*func)()) 71 | { 72 | thread_p t; 73 | 74 | for (t = all_thread; t < all_thread + MAX_THREAD; t++) { 75 | if (t->state == FREE) break; 76 | } 77 | t->sp = (int) (t->stack + STACK_SIZE); // set sp to the top of the stack 78 | t->sp -= 4; // space for return address 79 | * (int *) (t->sp) = (int)func; // push return address on stack 80 | t->sp -= 32; // space for registers that thread_switch expects 81 | t->state = RUNNABLE; 82 | } 83 | 84 | void 85 | thread_yield(void) 86 | { 87 | current_thread->state = RUNNABLE; 88 | thread_schedule(); 89 | } 90 | 91 | static void 92 | mythread(void) 93 | { 94 | int i; 95 | printf(1, "my thread running\n"); 96 | for (i = 0; i < 3; i++) { 97 | printf(1, "my thread 0x%x\n", (int) current_thread); 98 | thread_yield(); 99 | } 100 | printf(1, "my thread: exit\n"); 101 | current_thread->state = FREE; 102 | thread_schedule(); 103 | } 104 | 105 | 106 | int 107 | main(int argc, char *argv[]) 108 | { 109 | thread_init(); 110 | thread_create_my(mythread); 111 | thread_create_my(mythread); 112 | thread_schedule(); 113 | return 0; 114 | } 115 | -------------------------------------------------------------------------------- /code/spinlock.c: -------------------------------------------------------------------------------- 1 | // Mutual exclusion spin locks. 2 | 3 | #include "types.h" 4 | #include "defs.h" 5 | #include "param.h" 6 | #include "x86.h" 7 | #include "memlayout.h" 8 | #include "mmu.h" 9 | #include "proc.h" 10 | #include "spinlock.h" 11 | 12 | void 13 | initlock(struct spinlock *lk, char *name) 14 | { 15 | lk->name = name; 16 | lk->locked = 0; 17 | lk->cpu = 0; 18 | } 19 | 20 | // Acquire the lock. 21 | // Loops (spins) until the lock is acquired. 22 | // Holding a lock for a long time may cause 23 | // other CPUs to waste time spinning to acquire it. 24 | void 25 | acquire(struct spinlock *lk) 26 | { 27 | pushcli(); // disable interrupts to avoid deadlock. 28 | if(holding(lk)) 29 | panic("acquire"); 30 | 31 | // The xchg is atomic. 32 | // 将第二个参数x放入寄存器中与第一个指针参数所指的内容交换，返回所指内容原先的值。 33 | // 谈不上两数交换值。但是它可以“原子”的设置ptr所指内容并取出原值 34 | while(xchg(&lk->locked, 1) != 0) 35 | ; 36 | 37 | // Tell the C compiler and the processor to not move loads or stores 38 | // past this point, to ensure that the critical section's memory 39 | // references happen after the lock is acquired. 40 | __sync_synchronize(); 41 | 42 | // Record info about lock acquisition for debugging. 43 | lk->cpu = mycpu(); 44 | getcallerpcs(&lk, lk->pcs); 45 | } 46 | 47 | // Release the lock. 48 | void 49 | release(struct spinlock *lk) 50 | { 51 | if(!holding(lk)) 52 | panic("release"); 53 | 54 | lk->pcs[0] = 0; 55 | lk->cpu = 0; 56 | 57 | // Tell the C compiler and the processor to not move loads or stores 58 | // past this point, to ensure that all the stores in the critical 59 | // section are visible to other cores before the lock is released. 60 | // Both the C compiler and the hardware may re-order loads and 61 | // stores; __sync_synchronize() tells them both not to. 62 | __sync_synchronize(); 63 | 64 | // Release the lock, equivalent to lk->locked = 0. 65 | // This code can't use a C assignment, since it might 66 | // not be atomic. A real OS would use C atomics here. 67 | asm volatile("movl $0, %0" : "+m" (lk->locked) : ); 68 | 69 | popcli(); 70 | } 71 | 72 | // Record the current call stack in pcs[] by following the %ebp chain. 73 | void 74 | getcallerpcs(void *v, uint pcs[]) 75 | { 76 | uint *ebp; 77 | int i; 78 | 79 | ebp = (uint*)v - 2; 80 | for(i = 0; i < 10; i++){ 81 | if(ebp == 0 || ebp < (uint*)KERNBASE || ebp == (uint*)0xffffffff) 82 | break; 83 | pcs[i] = ebp[1]; // saved %eip 84 | ebp = (uint*)ebp[0]; // saved %ebp 85 | } 86 | for(; i < 10; i++) 87 | pcs[i] = 0; 88 | } 89 | 90 | // Check whether this cpu is holding the lock. 91 | int 92 | holding(struct spinlock *lock) 93 | { 94 | return lock->locked && lock->cpu == mycpu(); 95 | } 96 | 97 | 98 | // Pushcli/popcli are like cli/sti except that they are matched: 99 | // it takes two popcli to undo two pushcli. Also, if interrupts 100 | // are off, then pushcli, popcli leaves them off. 101 | 102 | void 103 | pushcli(void) 104 | { 105 | int eflags; 106 | 107 | eflags = readeflags(); 108 | cli(); 109 | if(mycpu()->ncli == 0) 110 | mycpu()->intena = eflags & FL_IF; 111 | mycpu()->ncli += 1; 112 | } 113 | 114 | void 115 | popcli(void) 116 | { 117 | if(readeflags()&FL_IF) 118 | panic("popcli - interruptible"); 119 | if(--mycpu()->ncli < 0) 120 | panic("popcli"); 121 | if(mycpu()->ncli == 0 && mycpu()->intena) 122 | sti(); 123 | } 124 | 125 | -------------------------------------------------------------------------------- /code/file.c: -------------------------------------------------------------------------------- 1 | // 2 | // File descriptors 3 | // 4 | 5 | #include "types.h" 6 | #include "defs.h" 7 | #include "param.h" 8 | #include "fs.h" 9 | #include "spinlock.h" 10 | #include "sleeplock.h" 11 | #include "file.h" 12 | 13 | struct devsw devsw[NDEV]; 14 | struct { 15 | struct spinlock lock; 16 | struct file file[NFILE]; 17 | } ftable; 18 | 19 | void 20 | fileinit(void) 21 | { 22 | initlock(&ftable.lock, "ftable"); 23 | } 24 | 25 | // Allocate a file structure. 26 | struct file* 27 | filealloc(void) 28 | { 29 | struct file *f; 30 | 31 | acquire(&ftable.lock); 32 | for(f = ftable.file; f < ftable.file + NFILE; f++){ 33 | if(f->ref == 0){ 34 | f->ref = 1; 35 | release(&ftable.lock); 36 | return f; 37 | } 38 | } 39 | release(&ftable.lock); 40 | return 0; 41 | } 42 | 43 | // Increment ref count for file f. 44 | struct file* 45 | filedup(struct file *f) 46 | { 47 | acquire(&ftable.lock); 48 | if(f->ref < 1) 49 | panic("filedup"); 50 | f->ref++; 51 | release(&ftable.lock); 52 | return f; 53 | } 54 | 55 | // Close file f. (Decrement ref count, close when reaches 0.) 56 | void 57 | fileclose(struct file *f) 58 | { 59 | struct file ff; 60 | 61 | acquire(&ftable.lock); 62 | if(f->ref < 1) 63 | panic("fileclose"); 64 | if(--f->ref > 0){ 65 | release(&ftable.lock); 66 | return; 67 | } 68 | ff = *f; 69 | f->ref = 0; 70 | f->type = FD_NONE; 71 | release(&ftable.lock); 72 | 73 | if(ff.type == FD_PIPE) 74 | pipeclose(ff.pipe, ff.writable); 75 | else if(ff.type == FD_INODE){ 76 | begin_op(); 77 | iput(ff.ip); 78 | end_op(); 79 | } 80 | } 81 | 82 | // Get metadata about file f. 83 | int 84 | filestat(struct file *f, struct stat *st) 85 | { 86 | if(f->type == FD_INODE){ 87 | ilock(f->ip); 88 | stati(f->ip, st); 89 | iunlock(f->ip); 90 | return 0; 91 | } 92 | return -1; 93 | } 94 | 95 | // Read from file f. 96 | int 97 | fileread(struct file *f, char *addr, int n) 98 | { 99 | int r; 100 | 101 | if(f->readable == 0) 102 | return -1; 103 | if(f->type == FD_PIPE) 104 | return piperead(f->pipe, addr, n); 105 | if(f->type == FD_INODE){ 106 | ilock(f->ip); 107 | if((r = readi(f->ip, addr, f->off, n)) > 0) 108 | f->off += r; 109 | iunlock(f->ip); 110 | return r; 111 | } 112 | panic("fileread"); 113 | } 114 | 115 | //PAGEBREAK! 116 | // Write to file f. 117 | int 118 | filewrite(struct file *f, char *addr, int n) 119 | { 120 | int r; 121 | 122 | if(f->writable == 0) 123 | return -1; 124 | if(f->type == FD_PIPE) 125 | return pipewrite(f->pipe, addr, n); 126 | if(f->type == FD_INODE){ 127 | // write a few blocks at a time to avoid exceeding 128 | // the maximum log transaction size, including 129 | // i-node, indirect block, allocation blocks, 130 | // and 2 blocks of slop for non-aligned writes. 131 | // this really belongs lower down, since writei() 132 | // might be writing a device like the console. 133 | int max = ((MAXOPBLOCKS-1-1-2) / 2) * 512; 134 | int i = 0; 135 | while(i < n){ 136 | int n1 = n - i; 137 | if(n1 > max) 138 | n1 = max; 139 | 140 | begin_op(); 141 | ilock(f->ip); 142 | if ((r = writei(f->ip, addr + i, f->off, n1)) > 0) 143 | f->off += r; 144 | iunlock(f->ip); 145 | end_op(); 146 | 147 | if(r < 0) 148 | break; 149 | if(r != n1) 150 | panic("short filewrite"); 151 | i += r; 152 | } 153 | return i == n ? n : -1; 154 | } 155 | panic("filewrite"); 156 | } 157 | 158 | -------------------------------------------------------------------------------- /code/main.c: -------------------------------------------------------------------------------- 1 | #include "types.h" 2 | #include "defs.h" 3 | #include "param.h" 4 | #include "memlayout.h" 5 | #include "mmu.h" 6 | #include "proc.h" 7 | #include "x86.h" 8 | 9 | static void startothers(void); 10 | static void mpmain(void) __attribute__((noreturn)); 11 | extern pde_t *kpgdir; 12 | extern char end[]; // first address after kernel loaded from ELF file 13 | 14 | // Bootstrap processor starts running C code here. 15 | // Allocate a real stack and switch to it, first 16 | // doing some setup required for memory allocator to work. 17 | int 18 | main(void) 19 | { 20 | kinit1(end, P2V(4*1024*1024)); // phys page allocator 21 | kvmalloc(); // kernel page table 22 | mpinit(); // detect other processors 23 | lapicinit(); // interrupt controller 24 | seginit(); // segment descriptors 25 | picinit(); // disable pic 26 | ioapicinit(); // another interrupt controller 27 | consoleinit(); // console hardware 28 | uartinit(); // serial port 29 | pinit(); // process table 30 | tvinit(); // trap vectors 31 | binit(); // buffer cache 32 | fileinit(); // file table 33 | ideinit(); // disk 34 | startothers(); // start other processors 35 | kinit2(P2V(4*1024*1024), P2V(PHYSTOP)); // must come after startothers() 36 | userinit(); // first user process 37 | mpmain(); // finish this processor's setup 38 | } 39 | 40 | // Other CPUs jump here from entryother.S. 41 | static void 42 | mpenter(void) 43 | { 44 | switchkvm(); 45 | seginit(); 46 | lapicinit(); 47 | mpmain(); 48 | } 49 | 50 | // Common CPU setup code. 51 | static void 52 | mpmain(void) 53 | { 54 | cprintf("cpu%d: starting %d\n", cpuid(), cpuid()); 55 | idtinit(); // load idt register 56 | xchg(&(mycpu()->started), 1); // tell startothers() we're up 57 | scheduler(); // start running processes 58 | } 59 | 60 | pde_t entrypgdir[]; // For entry.S 61 | 62 | // Start the non-boot (AP) processors. 63 | static void 64 | startothers(void) 65 | { 66 | extern uchar _binary_entryother_start[], _binary_entryother_size[]; 67 | uchar *code; 68 | struct cpu *c; 69 | char *stack; 70 | 71 | // Write entry code to unused memory at 0x7000. 72 | // The linker has placed the image of entryother.S in 73 | // _binary_entryother_start. 74 | code = P2V(0x7000); 75 | memmove(code, _binary_entryother_start, (uint)_binary_entryother_size); 76 | 77 | for(c = cpus; c < cpus+ncpu; c++){ 78 | if(c == mycpu()) // We've started already. 79 | continue; 80 | 81 | // Tell entryother.S what stack to use, where to enter, and what 82 | // pgdir to use. We cannot use kpgdir yet, because the AP processor 83 | // is running in low memory, so we use entrypgdir for the APs too. 84 | stack = kalloc(); 85 | *(void**)(code-4) = stack + KSTACKSIZE; 86 | *(void**)(code-8) = mpenter; 87 | *(int**)(code-12) = (void *) V2P(entrypgdir); 88 | 89 | lapicstartap(c->apicid, V2P(code)); 90 | 91 | // wait for cpu to finish mpmain() 92 | while(c->started == 0) 93 | ; 94 | } 95 | } 96 | 97 | // The boot page table used in entry.S and entryother.S. 98 | // Page directories (and page tables) must start on page boundaries, 99 | // hence the __aligned__ attribute. 100 | // PTE_PS in a page directory entry enables 4Mbyte pages. 101 | 102 | __attribute__((__aligned__(PGSIZE))) 103 | pde_t entrypgdir[NPDENTRIES] = { 104 | // Map VA's [0, 4MB) to PA's [0, 4MB) 105 | [0] = (0) | PTE_P | PTE_W | PTE_PS, 106 | // Map VA's [KERNBASE, KERNBASE+4MB) to PA's [0, 4MB) 107 | [KERNBASE>>PDXSHIFT] = (0) | PTE_P | PTE_W | PTE_PS, 108 | }; 109 | 110 | //PAGEBREAK! 111 | // Blank page. 112 | //PAGEBREAK! 113 | // Blank page. 114 | //PAGEBREAK! 115 | // Blank page. 116 | 117 | -------------------------------------------------------------------------------- /code/mp.c: -------------------------------------------------------------------------------- 1 | // Multiprocessor support 2 | // Search memory for MP description structures. 3 | // http://developer.intel.com/design/pentium/datashts/24201606.pdf 4 | 5 | #include "types.h" 6 | #include "defs.h" 7 | #include "param.h" 8 | #include "memlayout.h" 9 | #include "mp.h" 10 | #include "x86.h" 11 | #include "mmu.h" 12 | #include "proc.h" 13 | 14 | struct cpu cpus[NCPU]; 15 | int ncpu; 16 | uchar ioapicid; 17 | 18 | static uchar 19 | sum(uchar *addr, int len) 20 | { 21 | int i, sum; 22 | 23 | sum = 0; 24 | for(i=0; iphysaddr == 0) 79 | return 0; 80 | conf = (struct mpconf*) P2V((uint) mp->physaddr); 81 | if(memcmp(conf, "PCMP", 4) != 0) 82 | return 0; 83 | if(conf->version != 1 && conf->version != 4) 84 | return 0; 85 | if(sum((uchar*)conf, conf->length) != 0) 86 | return 0; 87 | *pmp = mp; 88 | return conf; 89 | } 90 | 91 | void 92 | mpinit(void) 93 | { 94 | uchar *p, *e; 95 | int ismp; 96 | struct mp *mp; 97 | struct mpconf *conf; 98 | struct mpproc *proc; 99 | struct mpioapic *ioapic; 100 | 101 | if((conf = mpconfig(&mp)) == 0) 102 | panic("Expect to run on an SMP"); 103 | ismp = 1; 104 | lapic = (uint*)conf->lapicaddr; 105 | for(p=(uchar*)(conf+1), e=(uchar*)conf+conf->length; papicid; // apicid may differ from ncpu 111 | ncpu++; 112 | } 113 | p += sizeof(struct mpproc); 114 | continue; 115 | case MPIOAPIC: 116 | ioapic = (struct mpioapic*)p; 117 | ioapicid = ioapic->apicno; 118 | p += sizeof(struct mpioapic); 119 | continue; 120 | case MPBUS: 121 | case MPIOINTR: 122 | case MPLINTR: 123 | p += 8; 124 | continue; 125 | default: 126 | ismp = 0; 127 | break; 128 | } 129 | } 130 | if(!ismp) 131 | panic("Didn't find a suitable machine"); 132 | 133 | if(mp->imcrp){ 134 | // Bochs doesn't support IMCR, so this doesn't run on Bochs. 135 | // But it would on real hardware. 136 | outb(0x22, 0x70); // Select IMCR 137 | outb(0x23, inb(0x23) | 1); // Mask external interrupts. 138 | } 139 | } 140 | -------------------------------------------------------------------------------- /code/trap.c: -------------------------------------------------------------------------------- 1 | #include "types.h" 2 | #include "defs.h" 3 | #include "param.h" 4 | #include "memlayout.h" 5 | #include "mmu.h" 6 | #include "proc.h" 7 | #include "x86.h" 8 | #include "traps.h" 9 | #include "spinlock.h" 10 | 11 | // Interrupt descriptor table (shared by all CPUs). 12 | struct gatedesc idt[256]; 13 | extern uint vectors[]; // in vectors.S: array of 256 entry pointers 14 | struct spinlock tickslock; 15 | int mappages(pde_t *pgdir, void *va, uint size, uint pa, int perm); 16 | uint ticks; 17 | 18 | void 19 | tvinit(void) 20 | { 21 | int i; 22 | 23 | for(i = 0; i < 256; i++) 24 | SETGATE(idt[i], 0, SEG_KCODE<<3, vectors[i], 0); 25 | SETGATE(idt[T_SYSCALL], 1, SEG_KCODE<<3, vectors[T_SYSCALL], DPL_USER); 26 | 27 | initlock(&tickslock, "time"); 28 | } 29 | 30 | void 31 | idtinit(void) 32 | { 33 | lidt(idt, sizeof(idt)); 34 | } 35 | 36 | //PAGEBREAK: 41 37 | void 38 | trap(struct trapframe *tf) 39 | { 40 | if(tf->trapno == T_SYSCALL){ 41 | if(myproc()->killed) 42 | exit(); 43 | myproc()->tf = tf; 44 | syscall(); 45 | if(myproc()->killed) 46 | exit(); 47 | return; 48 | } 49 | 50 | if(tf->trapno==T_PGFLT){ 51 | char *mem=kalloc(); 52 | if(!mem){ 53 | panic("we have run out of mem\n"); 54 | } 55 | memset(mem,0,PGSIZE); 56 | mappages(myproc()->pgdir, (char *) PGROUNDDOWN(rcr2()), PGSIZE, V2P(mem),PTE_W|PTE_U); 57 | return; 58 | } 59 | switch(tf->trapno){ 60 | case T_IRQ0 + IRQ_TIMER: 61 | if(cpuid() == 0){ 62 | acquire(&tickslock); 63 | ticks++; 64 | wakeup(&ticks); 65 | release(&tickslock); 66 | } 67 | lapiceoi(); 68 | //首先通过tf->esp-=4;tf->esp=tf->eip将原来执行的位置压入栈内， 69 | //然后设置tf->eip指向我们写的handler程序入口。（这样模拟用户进程中的函数调用)。 70 | if(myproc() != 0 && (tf->cs & 3) == 3){ 71 | myproc()->elapsedticks+=1; 72 | if(myproc()->elapsedticks==myproc()->alarmticks){ 73 | myproc()->elapsedticks=0; 74 | tf->esp-=4; 75 | *(uint *) tf->esp=tf->eip; 76 | tf->eip=(uint)myproc()->handler; 77 | } 78 | } 79 | break; 80 | case T_IRQ0 + IRQ_IDE: 81 | ideintr(); 82 | lapiceoi(); 83 | break; 84 | case T_IRQ0 + IRQ_IDE+1: 85 | // Bochs generates spurious IDE1 interrupts. 86 | break; 87 | case T_IRQ0 + IRQ_KBD: 88 | kbdintr(); 89 | lapiceoi(); 90 | break; 91 | case T_IRQ0 + IRQ_COM1: 92 | uartintr(); 93 | lapiceoi(); 94 | break; 95 | case T_IRQ0 + 7: 96 | case T_IRQ0 + IRQ_SPURIOUS: 97 | cprintf("cpu%d: spurious interrupt at %x:%x\n", 98 | cpuid(), tf->cs, tf->eip); 99 | lapiceoi(); 100 | break; 101 | 102 | //PAGEBREAK: 13 103 | default: 104 | if(myproc() == 0 || (tf->cs&3) == 0){ 105 | // In kernel, it must be our mistake. 106 | cprintf("unexpected trap %d from cpu %d eip %x (cr2=0x%x)\n", 107 | tf->trapno, cpuid(), tf->eip, rcr2()); 108 | panic("trap"); 109 | } 110 | // In user space, assume process misbehaved. 111 | cprintf("pid %d %s: trap %d err %d on cpu %d " 112 | "eip 0x%x addr 0x%x--kill proc\n", 113 | myproc()->pid, myproc()->name, tf->trapno, 114 | tf->err, cpuid(), tf->eip, rcr2()); 115 | myproc()->killed = 1; 116 | } 117 | 118 | // Force process exit if it has been killed and is in user space. 119 | // (If it is still executing in the kernel, let it keep running 120 | // until it gets to the regular system call return.) 121 | if(myproc() && myproc()->killed && (tf->cs&3) == DPL_USER) 122 | exit(); 123 | 124 | // Force process to give up CPU on clock tick. 125 | // If interrupts were on while locks held, would need to check nlock. 126 | if(myproc() && myproc()->state == RUNNING && 127 | tf->trapno == T_IRQ0+IRQ_TIMER) 128 | yield(); 129 | 130 | // Check if the process has been killed since we yielded 131 | if(myproc() && myproc()->killed && (tf->cs&3) == DPL_USER) 132 | exit(); 133 | } 134 | -------------------------------------------------------------------------------- /code/kbd.h: -------------------------------------------------------------------------------- 1 | // PC keyboard interface constants 2 | 3 | #define KBSTATP 0x64 // kbd controller status port(I) 4 | #define KBS_DIB 0x01 // kbd data in buffer 5 | #define KBDATAP 0x60 // kbd data port(I) 6 | 7 | #define NO 0 8 | 9 | #define SHIFT (1<<0) 10 | #define CTL (1<<1) 11 | #define ALT (1<<2) 12 | 13 | #define CAPSLOCK (1<<3) 14 | #define NUMLOCK (1<<4) 15 | #define SCROLLLOCK (1<<5) 16 | 17 | #define E0ESC (1<<6) 18 | 19 | // Special keycodes 20 | #define KEY_HOME 0xE0 21 | #define KEY_END 0xE1 22 | #define KEY_UP 0xE2 23 | #define KEY_DN 0xE3 24 | #define KEY_LF 0xE4 25 | #define KEY_RT 0xE5 26 | #define KEY_PGUP 0xE6 27 | #define KEY_PGDN 0xE7 28 | #define KEY_INS 0xE8 29 | #define KEY_DEL 0xE9 30 | 31 | // C('A') == Control-A 32 | #define C(x) (x - '@') 33 | 34 | static uchar shiftcode[256] = 35 | { 36 | [0x1D] CTL, 37 | [0x2A] SHIFT, 38 | [0x36] SHIFT, 39 | [0x38] ALT, 40 | [0x9D] CTL, 41 | [0xB8] ALT 42 | }; 43 | 44 | static uchar togglecode[256] = 45 | { 46 | [0x3A] CAPSLOCK, 47 | [0x45] NUMLOCK, 48 | [0x46] SCROLLLOCK 49 | }; 50 | 51 | static uchar normalmap[256] = 52 | { 53 | NO, 0x1B, '1', '2', '3', '4', '5', '6', // 0x00 54 | '7', '8', '9', '0', '-', '=', '\b', '\t', 55 | 'q', 'w', 'e', 'r', 't', 'y', 'u', 'i', // 0x10 56 | 'o', 'p', '[', ']', '\n', NO, 'a', 's', 57 | 'd', 'f', 'g', 'h', 'j', 'k', 'l', ';', // 0x20 58 | '\'', '`', NO, '\\', 'z', 'x', 'c', 'v', 59 | 'b', 'n', 'm', ',', '.', '/', NO, '*', // 0x30 60 | NO, ' ', NO, NO, NO, NO, NO, NO, 61 | NO, NO, NO, NO, NO, NO, NO, '7', // 0x40 62 | '8', '9', '-', '4', '5', '6', '+', '1', 63 | '2', '3', '0', '.', NO, NO, NO, NO, // 0x50 64 | [0x9C] '\n', // KP_Enter 65 | [0xB5] '/', // KP_Div 66 | [0xC8] KEY_UP, [0xD0] KEY_DN, 67 | [0xC9] KEY_PGUP, [0xD1] KEY_PGDN, 68 | [0xCB] KEY_LF, [0xCD] KEY_RT, 69 | [0x97] KEY_HOME, [0xCF] KEY_END, 70 | [0xD2] KEY_INS, [0xD3] KEY_DEL 71 | }; 72 | 73 | static uchar shiftmap[256] = 74 | { 75 | NO, 033, '!', '@', '#', '$', '%', '^', // 0x00 76 | '&', '*', '(', ')', '_', '+', '\b', '\t', 77 | 'Q', 'W', 'E', 'R', 'T', 'Y', 'U', 'I', // 0x10 78 | 'O', 'P', '{', '}', '\n', NO, 'A', 'S', 79 | 'D', 'F', 'G', 'H', 'J', 'K', 'L', ':', // 0x20 80 | '"', '~', NO, '|', 'Z', 'X', 'C', 'V', 81 | 'B', 'N', 'M', '<', '>', '?', NO, '*', // 0x30 82 | NO, ' ', NO, NO, NO, NO, NO, NO, 83 | NO, NO, NO, NO, NO, NO, NO, '7', // 0x40 84 | '8', '9', '-', '4', '5', '6', '+', '1', 85 | '2', '3', '0', '.', NO, NO, NO, NO, // 0x50 86 | [0x9C] '\n', // KP_Enter 87 | [0xB5] '/', // KP_Div 88 | [0xC8] KEY_UP, [0xD0] KEY_DN, 89 | [0xC9] KEY_PGUP, [0xD1] KEY_PGDN, 90 | [0xCB] KEY_LF, [0xCD] KEY_RT, 91 | [0x97] KEY_HOME, [0xCF] KEY_END, 92 | [0xD2] KEY_INS, [0xD3] KEY_DEL 93 | }; 94 | 95 | static uchar ctlmap[256] = 96 | { 97 | NO, NO, NO, NO, NO, NO, NO, NO, 98 | NO, NO, NO, NO, NO, NO, NO, NO, 99 | C('Q'), C('W'), C('E'), C('R'), C('T'), C('Y'), C('U'), C('I'), 100 | C('O'), C('P'), NO, NO, '\r', NO, C('A'), C('S'), 101 | C('D'), C('F'), C('G'), C('H'), C('J'), C('K'), C('L'), NO, 102 | NO, NO, NO, C('\\'), C('Z'), C('X'), C('C'), C('V'), 103 | C('B'), C('N'), C('M'), NO, NO, C('/'), NO, NO, 104 | [0x9C] '\r', // KP_Enter 105 | [0xB5] C('/'), // KP_Div 106 | [0xC8] KEY_UP, [0xD0] KEY_DN, 107 | [0xC9] KEY_PGUP, [0xD1] KEY_PGDN, 108 | [0xCB] KEY_LF, [0xCD] KEY_RT, 109 | [0x97] KEY_HOME, [0xCF] KEY_END, 110 | [0xD2] KEY_INS, [0xD3] KEY_DEL 111 | }; 112 | 113 | -------------------------------------------------------------------------------- /code/bio.c: -------------------------------------------------------------------------------- 1 | // Buffer cache. 2 | // 3 | // The buffer cache is a linked list of buf structures holding 4 | // cached copies of disk block contents. Caching disk blocks 5 | // in memory reduces the number of disk reads and also provides 6 | // a synchronization point for disk blocks used by multiple processes. 7 | // 8 | // Interface: 9 | // * To get a buffer for a particular disk block, call bread. 10 | // * After changing buffer data, call bwrite to write it to disk. 11 | // * When done with the buffer, call brelse. 12 | // * Do not use the buffer after calling brelse. 13 | // * Only one process at a time can use a buffer, 14 | // so do not keep them longer than necessary. 15 | // 16 | // The implementation uses two state flags internally: 17 | // * B_VALID: the buffer data has been read from the disk. 18 | // * B_DIRTY: the buffer data has been modified 19 | // and needs to be written to disk. 20 | 21 | #include "types.h" 22 | #include "defs.h" 23 | #include "param.h" 24 | #include "spinlock.h" 25 | #include "sleeplock.h" 26 | #include "fs.h" 27 | #include "buf.h" 28 | 29 | struct { 30 | struct spinlock lock; 31 | struct buf buf[NBUF]; 32 | 33 | // Linked list of all buffers, through prev/next. 34 | // head.next is most recently used. 35 | struct buf head; 36 | } bcache; 37 | 38 | void 39 | binit(void) 40 | { 41 | struct buf *b; 42 | 43 | initlock(&bcache.lock, "bcache"); 44 | 45 | //PAGEBREAK! 46 | // Create linked list of buffers 47 | bcache.head.prev = &bcache.head; 48 | bcache.head.next = &bcache.head; 49 | for(b = bcache.buf; b < bcache.buf+NBUF; b++){ 50 | b->next = bcache.head.next; 51 | b->prev = &bcache.head; 52 | initsleeplock(&b->lock, "buffer"); 53 | bcache.head.next->prev = b; 54 | bcache.head.next = b; 55 | } 56 | } 57 | 58 | // Look through buffer cache for block on device dev. 59 | // If not found, allocate a buffer. 60 | // In either case, return locked buffer. 61 | static struct buf* 62 | bget(uint dev, uint blockno) 63 | { 64 | struct buf *b; 65 | 66 | acquire(&bcache.lock); 67 | 68 | // Is the block already cached? 69 | for(b = bcache.head.next; b != &bcache.head; b = b->next){ 70 | if(b->dev == dev && b->blockno == blockno){ 71 | b->refcnt++; 72 | release(&bcache.lock); 73 | acquiresleep(&b->lock); 74 | return b; 75 | } 76 | } 77 | 78 | // Not cached; recycle an unused buffer. 79 | // Even if refcnt==0, B_DIRTY indicates a buffer is in use 80 | // because log.c has modified it but not yet committed it. 81 | for(b = bcache.head.prev; b != &bcache.head; b = b->prev){ 82 | if(b->refcnt == 0 && (b->flags & B_DIRTY) == 0) { 83 | b->dev = dev; 84 | b->blockno = blockno; 85 | b->flags = 0; 86 | b->refcnt = 1; 87 | release(&bcache.lock); 88 | acquiresleep(&b->lock); 89 | return b; 90 | } 91 | } 92 | panic("bget: no buffers"); 93 | } 94 | 95 | // Return a locked buf with the contents of the indicated block. 96 | struct buf* 97 | bread(uint dev, uint blockno) 98 | { 99 | struct buf *b; 100 | 101 | b = bget(dev, blockno); 102 | if((b->flags & B_VALID) == 0) { 103 | iderw(b); 104 | } 105 | return b; 106 | } 107 | 108 | // Write b's contents to disk. Must be locked. 109 | void 110 | bwrite(struct buf *b) 111 | { 112 | if(!holdingsleep(&b->lock)) 113 | panic("bwrite"); 114 | b->flags |= B_DIRTY; 115 | iderw(b); 116 | } 117 | 118 | // Release a locked buffer. 119 | // Move to the head of the MRU list. 120 | void 121 | brelse(struct buf *b) 122 | { 123 | if(!holdingsleep(&b->lock)) 124 | panic("brelse"); 125 | 126 | releasesleep(&b->lock); 127 | 128 | acquire(&bcache.lock); 129 | b->refcnt--; 130 | if (b->refcnt == 0) { 131 | // no one is waiting for it. 132 | b->next->prev = b->prev; 133 | b->prev->next = b->next; 134 | b->next = bcache.head.next; 135 | b->prev = &bcache.head; 136 | bcache.head.next->prev = b; 137 | bcache.head.next = b; 138 | } 139 | 140 | release(&bcache.lock); 141 | } 142 | //PAGEBREAK! 143 | // Blank page. 144 | 145 | -------------------------------------------------------------------------------- /code/syscall.c: -------------------------------------------------------------------------------- 1 | #include "types.h" 2 | #include "defs.h" 3 | #include "param.h" 4 | #include "memlayout.h" 5 | #include "mmu.h" 6 | #include "proc.h" 7 | #include "x86.h" 8 | #include "syscall.h" 9 | 10 | // User code makes a system call with INT T_SYSCALL. 11 | // System call number in %eax. 12 | // Arguments on the stack, from the user call to the C 13 | // library system call function. The saved user %esp points 14 | // to a saved program counter, and then the first argument. 15 | 16 | // Fetch the int at addr from the current process. 17 | int 18 | fetchint(uint addr, int *ip) 19 | { 20 | struct proc *curproc = myproc(); 21 | 22 | if(addr >= curproc->sz || addr+4 > curproc->sz) 23 | return -1; 24 | *ip = *(int*)(addr); 25 | return 0; 26 | } 27 | 28 | // Fetch the nul-terminated string at addr from the current process. 29 | // Doesn't actually copy the string - just sets *pp to point at it. 30 | // Returns length of string, not including nul. 31 | int 32 | fetchstr(uint addr, char **pp) 33 | { 34 | char *s, *ep; 35 | struct proc *curproc = myproc(); 36 | 37 | if(addr >= curproc->sz) 38 | return -1; 39 | *pp = (char*)addr; 40 | ep = (char*)curproc->sz; 41 | for(s = *pp; s < ep; s++){ 42 | if(*s == 0) 43 | return s - *pp; 44 | } 45 | return -1; 46 | } 47 | 48 | // Fetch the nth 32-bit system call argument. 49 | int 50 | argint(int n, int *ip) 51 | { 52 | return fetchint((myproc()->tf->esp) + 4 + 4*n, ip); 53 | } 54 | 55 | // Fetch the nth word-sized system call argument as a pointer 56 | // to a block of memory of size bytes. Check that the pointer 57 | // lies within the process address space. 58 | int 59 | argptr(int n, char **pp, int size) 60 | { 61 | int i; 62 | struct proc *curproc = myproc(); 63 | 64 | if(argint(n, &i) < 0) 65 | return -1; 66 | if(size < 0 || (uint)i >= curproc->sz || (uint)i+size > curproc->sz) 67 | return -1; 68 | *pp = (char*)i; 69 | return 0; 70 | } 71 | 72 | // Fetch the nth word-sized system call argument as a string pointer. 73 | // Check that the pointer is valid and the string is nul-terminated. 74 | // (There is no shared writable memory, so the string can't change 75 | // between this check and being used by the kernel.) 76 | int 77 | argstr(int n, char **pp) 78 | { 79 | int addr; 80 | if(argint(n, &addr) < 0) 81 | return -1; 82 | return fetchstr(addr, pp); 83 | } 84 | 85 | extern int sys_chdir(void); 86 | extern int sys_close(void); 87 | extern int sys_dup(void); 88 | extern int sys_exec(void); 89 | extern int sys_exit(void); 90 | extern int sys_fork(void); 91 | extern int sys_fstat(void); 92 | extern int sys_getpid(void); 93 | extern int sys_kill(void); 94 | extern int sys_link(void); 95 | extern int sys_mkdir(void); 96 | extern int sys_mknod(void); 97 | extern int sys_open(void); 98 | extern int sys_pipe(void); 99 | extern int sys_read(void); 100 | extern int sys_sbrk(void); 101 | extern int sys_sleep(void); 102 | extern int sys_unlink(void); 103 | extern int sys_wait(void); 104 | extern int sys_write(void); 105 | extern int sys_uptime(void); 106 | extern int sys_date(void); 107 | extern int sys_alarm(void); 108 | 109 | static int (*syscalls[])(void) = { 110 | [SYS_fork] sys_fork, 111 | [SYS_exit] sys_exit, 112 | [SYS_wait] sys_wait, 113 | [SYS_pipe] sys_pipe, 114 | [SYS_read] sys_read, 115 | [SYS_kill] sys_kill, 116 | [SYS_exec] sys_exec, 117 | [SYS_fstat] sys_fstat, 118 | [SYS_chdir] sys_chdir, 119 | [SYS_dup] sys_dup, 120 | [SYS_getpid] sys_getpid, 121 | [SYS_sbrk] sys_sbrk, 122 | [SYS_sleep] sys_sleep, 123 | [SYS_uptime] sys_uptime, 124 | [SYS_open] sys_open, 125 | [SYS_write] sys_write, 126 | [SYS_mknod] sys_mknod, 127 | [SYS_unlink] sys_unlink, 128 | [SYS_link] sys_link, 129 | [SYS_mkdir] sys_mkdir, 130 | [SYS_close] sys_close, 131 | [SYS_date] sys_date, 132 | [SYS_alarm] sys_alarm, 133 | }; 134 | 135 | void 136 | syscall(void) 137 | { 138 | int num; 139 | struct proc *curproc = myproc(); 140 | 141 | num = curproc->tf->eax; 142 | if(num > 0 && num < NELEM(syscalls) && syscalls[num]) { 143 | curproc->tf->eax = syscalls[num](); 144 | } else { 145 | cprintf("%d %s: unknown sys call %d\n", 146 | curproc->pid, curproc->name, num); 147 | curproc->tf->eax = -1; 148 | } 149 | } 150 | 151 | -------------------------------------------------------------------------------- /code/x86.h: -------------------------------------------------------------------------------- 1 | // Routines to let C code use special x86 instructions. 2 | 3 | static inline uchar 4 | inb(ushort port) 5 | { 6 | uchar data; 7 | 8 | asm volatile("in %1,%0" : "=a" (data) : "d" (port)); 9 | return data; 10 | } 11 | 12 | static inline void 13 | insl(int port, void *addr, int cnt) 14 | { 15 | asm volatile("cld; rep insl" : 16 | "=D" (addr), "=c" (cnt) : 17 | "d" (port), "0" (addr), "1" (cnt) : 18 | "memory", "cc"); 19 | } 20 | 21 | static inline void 22 | outb(ushort port, uchar data) 23 | { 24 | asm volatile("out %0,%1" : : "a" (data), "d" (port)); 25 | } 26 | 27 | static inline void 28 | outw(ushort port, ushort data) 29 | { 30 | asm volatile("out %0,%1" : : "a" (data), "d" (port)); 31 | } 32 | 33 | static inline void 34 | outsl(int port, const void *addr, int cnt) 35 | { 36 | asm volatile("cld; rep outsl" : 37 | "=S" (addr), "=c" (cnt) : 38 | "d" (port), "0" (addr), "1" (cnt) : 39 | "cc"); 40 | } 41 | 42 | static inline void 43 | stosb(void *addr, int data, int cnt) 44 | { 45 | asm volatile("cld; rep stosb" : 46 | "=D" (addr), "=c" (cnt) : 47 | "0" (addr), "1" (cnt), "a" (data) : 48 | "memory", "cc"); 49 | } 50 | 51 | static inline void 52 | stosl(void *addr, int data, int cnt) 53 | { 54 | asm volatile("cld; rep stosl" : 55 | "=D" (addr), "=c" (cnt) : 56 | "0" (addr), "1" (cnt), "a" (data) : 57 | "memory", "cc"); 58 | } 59 | 60 | struct segdesc; 61 | 62 | static inline void 63 | lgdt(struct segdesc *p, int size) 64 | { 65 | volatile ushort pd[3]; 66 | 67 | pd[0] = size-1; 68 | pd[1] = (uint)p; 69 | pd[2] = (uint)p >> 16; 70 | 71 | asm volatile("lgdt (%0)" : : "r" (pd)); 72 | } 73 | 74 | struct gatedesc; 75 | 76 | static inline void 77 | lidt(struct gatedesc *p, int size) 78 | { 79 | volatile ushort pd[3]; 80 | 81 | pd[0] = size-1; 82 | pd[1] = (uint)p; 83 | pd[2] = (uint)p >> 16; 84 | 85 | asm volatile("lidt (%0)" : : "r" (pd)); 86 | } 87 | 88 | static inline void 89 | ltr(ushort sel) 90 | { 91 | asm volatile("ltr %0" : : "r" (sel)); 92 | } 93 | 94 | static inline uint 95 | readeflags(void) 96 | { 97 | uint eflags; 98 | asm volatile("pushfl; popl %0" : "=r" (eflags)); 99 | return eflags; 100 | } 101 | 102 | static inline void 103 | loadgs(ushort v) 104 | { 105 | asm volatile("movw %0, %%gs" : : "r" (v)); 106 | } 107 | 108 | static inline void 109 | cli(void) 110 | { 111 | asm volatile("cli"); 112 | } 113 | 114 | static inline void 115 | sti(void) 116 | { 117 | asm volatile("sti"); 118 | } 119 | 120 | static inline uint 121 | xchg(volatile uint *addr, uint newval) 122 | { 123 | uint result; 124 | //将第二个参数x放入寄存器中与第一个指针参数所指的内容交换，返回所指内容原先的值。 125 | //谈不上两数交换值。但是它可以“原子”的设置ptr所指内容并取出原值 126 | // The + in "+m" denotes a read-modify-write operand. 127 | asm volatile("lock; xchgl %0, %1" : 128 | "+m" (*addr), "=a" (result) : 129 | "1" (newval) : 130 | "cc"); 131 | return result; 132 | } 133 | 134 | static inline uint 135 | rcr2(void) 136 | { 137 | uint val; 138 | asm volatile("movl %%cr2,%0" : "=r" (val)); 139 | return val; 140 | } 141 | 142 | static inline void 143 | lcr3(uint val) 144 | { 145 | asm volatile("movl %0,%%cr3" : : "r" (val)); 146 | } 147 | 148 | //PAGEBREAK: 36 149 | // Layout of the trap frame built on the stack by the 150 | // hardware and by trapasm.S, and passed to trap(). 151 | struct trapframe { 152 | // registers as pushed by pusha 153 | uint edi; 154 | uint esi; 155 | uint ebp; 156 | uint oesp; // useless & ignored 157 | uint ebx; 158 | uint edx; 159 | uint ecx; 160 | uint eax; 161 | 162 | // rest of trap frame 163 | ushort gs; 164 | ushort padding1; 165 | ushort fs; 166 | ushort padding2; 167 | ushort es; 168 | ushort padding3; 169 | ushort ds; 170 | ushort padding4; 171 | uint trapno; 172 | 173 | 174 | //save by the Int instruction 175 | // below here defined by x86 hardware 176 | uint err; 177 | uint eip; 178 | ushort cs; 179 | ushort padding5; 180 | uint eflags; 181 | 182 | // below here only when crossing rings, such as from user to kernel 183 | uint esp; 184 | ushort ss; 185 | ushort padding6; 186 | }; 187 | -------------------------------------------------------------------------------- /code/ide.c: -------------------------------------------------------------------------------- 1 | // Simple PIO-based (non-DMA) IDE driver code. 2 | 3 | #include "types.h" 4 | #include "defs.h" 5 | #include "param.h" 6 | #include "memlayout.h" 7 | #include "mmu.h" 8 | #include "proc.h" 9 | #include "x86.h" 10 | #include "traps.h" 11 | #include "spinlock.h" 12 | #include "sleeplock.h" 13 | #include "fs.h" 14 | #include "buf.h" 15 | 16 | #define SECTOR_SIZE 512 17 | #define IDE_BSY 0x80 18 | #define IDE_DRDY 0x40 19 | #define IDE_DF 0x20 20 | #define IDE_ERR 0x01 21 | 22 | #define IDE_CMD_READ 0x20 23 | #define IDE_CMD_WRITE 0x30 24 | #define IDE_CMD_RDMUL 0xc4 25 | #define IDE_CMD_WRMUL 0xc5 26 | 27 | // idequeue points to the buf now being read/written to the disk. 28 | // idequeue->qnext points to the next buf to be processed. 29 | // You must hold idelock while manipulating queue. 30 | 31 | static struct spinlock idelock; 32 | static struct buf *idequeue; 33 | 34 | static int havedisk1; 35 | static void idestart(struct buf*); 36 | 37 | // Wait for IDE disk to become ready. 38 | static int 39 | idewait(int checkerr) 40 | { 41 | int r; 42 | 43 | while(((r = inb(0x1f7)) & (IDE_BSY|IDE_DRDY)) != IDE_DRDY) 44 | ; 45 | if(checkerr && (r & (IDE_DF|IDE_ERR)) != 0) 46 | return -1; 47 | return 0; 48 | } 49 | 50 | void 51 | ideinit(void) 52 | { 53 | int i; 54 | 55 | initlock(&idelock, "ide"); 56 | ioapicenable(IRQ_IDE, ncpu - 1); 57 | idewait(0); 58 | 59 | // Check if disk 1 is present 60 | outb(0x1f6, 0xe0 | (1<<4)); 61 | for(i=0; i<1000; i++){ 62 | if(inb(0x1f7) != 0){ 63 | havedisk1 = 1; 64 | break; 65 | } 66 | } 67 | 68 | // Switch back to disk 0. 69 | outb(0x1f6, 0xe0 | (0<<4)); 70 | } 71 | 72 | // Start the request for b. Caller must hold idelock. 73 | static void 74 | idestart(struct buf *b) 75 | { 76 | if(b == 0) 77 | panic("idestart"); 78 | if(b->blockno >= FSSIZE) 79 | panic("incorrect blockno"); 80 | int sector_per_block = BSIZE/SECTOR_SIZE; 81 | int sector = b->blockno * sector_per_block; 82 | int read_cmd = (sector_per_block == 1) ? IDE_CMD_READ : IDE_CMD_RDMUL; 83 | int write_cmd = (sector_per_block == 1) ? IDE_CMD_WRITE : IDE_CMD_WRMUL; 84 | 85 | if (sector_per_block > 7) panic("idestart"); 86 | 87 | idewait(0); 88 | outb(0x3f6, 0); // generate interrupt 89 | outb(0x1f2, sector_per_block); // number of sectors 90 | outb(0x1f3, sector & 0xff); 91 | outb(0x1f4, (sector >> 8) & 0xff); 92 | outb(0x1f5, (sector >> 16) & 0xff); 93 | outb(0x1f6, 0xe0 | ((b->dev&1)<<4) | ((sector>>24)&0x0f)); 94 | if(b->flags & B_DIRTY){ 95 | outb(0x1f7, write_cmd); 96 | outsl(0x1f0, b->data, BSIZE/4); 97 | } else { 98 | outb(0x1f7, read_cmd); 99 | } 100 | } 101 | 102 | // Interrupt handler. 103 | void 104 | ideintr(void) 105 | { 106 | struct buf *b; 107 | 108 | // First queued buffer is the active request. 109 | acquire(&idelock); 110 | 111 | if((b = idequeue) == 0){ 112 | release(&idelock); 113 | return; 114 | } 115 | idequeue = b->qnext; 116 | 117 | // Read data if needed. 118 | if(!(b->flags & B_DIRTY) && idewait(1) >= 0) 119 | insl(0x1f0, b->data, BSIZE/4); 120 | 121 | // Wake process waiting for this buf. 122 | b->flags |= B_VALID; 123 | b->flags &= ~B_DIRTY; 124 | wakeup(b); 125 | 126 | // Start disk on next buf in queue. 127 | if(idequeue != 0) 128 | idestart(idequeue); 129 | 130 | release(&idelock); 131 | } 132 | 133 | //PAGEBREAK! 134 | // Sync buf with disk. 135 | // If B_DIRTY is set, write buf to disk, clear B_DIRTY, set B_VALID. 136 | // Else if B_VALID is not set, read buf from disk, set B_VALID. 137 | void 138 | iderw(struct buf *b) 139 | { 140 | struct buf **pp; 141 | 142 | if(!holdingsleep(&b->lock)) 143 | panic("iderw: buf not locked"); 144 | if((b->flags & (B_VALID|B_DIRTY)) == B_VALID) 145 | panic("iderw: nothing to do"); 146 | if(b->dev != 0 && !havedisk1) 147 | panic("iderw: ide disk 1 not present"); 148 | 149 | acquire(&idelock); //DOC:acquire-lock 150 | 151 | // Append b to idequeue. 152 | b->qnext = 0; 153 | for(pp=&idequeue; *pp; pp=&(*pp)->qnext) //DOC:insert-queue 154 | ; 155 | *pp = b; 156 | 157 | // Start disk if necessary. 158 | if(idequeue == b) 159 | idestart(b); 160 | 161 | // Wait for request to finish. 162 | while((b->flags & (B_VALID|B_DIRTY)) != B_VALID){ 163 | sleep(b, &idelock); 164 | } 165 | 166 | 167 | release(&idelock); 168 | } 169 | -------------------------------------------------------------------------------- /code/symlink.patch: -------------------------------------------------------------------------------- 1 | diff -r f8a4e40ab1d6 fs.c 2 | --- a/fs.c Thu Aug 30 14:32:06 2007 -0400 3 | +++ b/fs.c Thu Aug 30 14:29:02 2007 -0400 4 | @@ -577,12 +577,18 @@ skipelem(char *path, char *name) 5 | // If parent != 0, return the inode for the parent and copy the final 6 | // path element into name, which must have room for DIRSIZ bytes. 7 | static struct inode* 8 | -_namei(char *path, int parent, char *name) 9 | +_namei(struct inode *root, char *path, int parent, char *name, int depth) 10 | { 11 | struct inode *ip, *next; 12 | + char buf[100], tname[DIRSIZ]; 13 | + 14 | + if(depth > 5) 15 | + return 0; 16 | 17 | if(*path == '/') 18 | ip = iget(ROOTDEV, 1); 19 | + else if(root) 20 | + ip = idup(root); 21 | else 22 | ip = idup(cp->cwd); 23 | 24 | @@ -598,10 +604,24 @@ _namei(char *path, int parent, char *nam 25 | return ip; 26 | } 27 | if((next = dirlookup(ip, name, 0)) == 0){ 28 | + cprintf("did not find %s\n", name); 29 | iunlockput(ip); 30 | return 0; 31 | } 32 | - iunlockput(ip); 33 | + iunlock(ip); 34 | + ilock(next); 35 | + if(next->type == T_SYMLINK){ 36 | + if(next->size >= sizeof(buf) || readi(next, buf, 0, next->size) != next->size){ 37 | + iunlockput(next); 38 | + iput(ip); 39 | + return 0; 40 | + } 41 | + buf[next->size] = 0; 42 | + iunlockput(next); 43 | + next = _namei(ip, buf, 0, tname, depth+1); 44 | + }else 45 | + iunlock(next); 46 | + iput(ip); 47 | ip = next; 48 | } 49 | if(parent){ 50 | @@ -615,11 +635,11 @@ namei(char *path) 51 | namei(char *path) 52 | { 53 | char name[DIRSIZ]; 54 | - return _namei(path, 0, name); 55 | + return _namei(0, path, 0, name, 0); 56 | } 57 | 58 | struct inode* 59 | nameiparent(char *path, char *name) 60 | { 61 | - return _namei(path, 1, name); 62 | -} 63 | + return _namei(0, path, 1, name, 0); 64 | +} 65 | diff -r f8a4e40ab1d6 fs.h 66 | --- a/fs.h Thu Aug 30 14:32:06 2007 -0400 67 | +++ b/fs.h Thu Aug 30 13:05:43 2007 -0400 68 | @@ -33,6 +33,7 @@ struct dinode { 69 | #define T_DIR 1 // Directory 70 | #define T_FILE 2 // File 71 | #define T_DEV 3 // Special device 72 | +#define T_SYMLINK 4 // Symlink 73 | 74 | // Inodes per block. 75 | #define IPB (BSIZE / sizeof(struct dinode)) 76 | diff -r f8a4e40ab1d6 syscall.c 77 | --- a/syscall.c Thu Aug 30 14:32:06 2007 -0400 78 | +++ b/syscall.c Thu Aug 30 13:05:29 2007 -0400 79 | @@ -96,6 +96,7 @@ extern int sys_unlink(void); 80 | extern int sys_unlink(void); 81 | extern int sys_wait(void); 82 | extern int sys_write(void); 83 | +extern int sys_symlink(void); 84 | 85 | static int (*syscalls[])(void) = { 86 | [SYS_chdir] sys_chdir, 87 | @@ -118,6 +119,7 @@ static int (*syscalls[])(void) = { 88 | [SYS_unlink] sys_unlink, 89 | [SYS_wait] sys_wait, 90 | [SYS_write] sys_write, 91 | +[SYS_symlink] sys_symlink, 92 | }; 93 | 94 | void 95 | diff -r f8a4e40ab1d6 syscall.h 96 | --- a/syscall.h Thu Aug 30 14:32:06 2007 -0400 97 | +++ b/syscall.h Thu Aug 30 13:02:48 2007 -0400 98 | @@ -19,3 +19,4 @@ 99 | #define SYS_getpid 18 100 | #define SYS_sbrk 19 101 | #define SYS_sleep 20 102 | +#define SYS_symlink 21 103 | diff -r f8a4e40ab1d6 sysfile.c 104 | --- a/sysfile.c Thu Aug 30 14:32:06 2007 -0400 105 | +++ b/sysfile.c Thu Aug 30 13:10:31 2007 -0400 106 | @@ -257,6 +257,21 @@ create(char *path, int canexist, short t 107 | } 108 | 109 | int 110 | +sys_symlink(void) 111 | +{ 112 | + char *old, *new; 113 | + struct inode *ip; 114 | + 115 | + if(argstr(0, &old) < 0 || argstr(1, &new) < 0) 116 | + return -1; 117 | + if((ip = create(new, 0, T_SYMLINK, 0, 0)) == 0) 118 | + return -1; 119 | + writei(ip, old, 0, strlen(old)); 120 | + iunlockput(ip); 121 | + return 0; 122 | +} 123 | + 124 | +int 125 | sys_open(void) 126 | { 127 | char *path; 128 | @@ -393,3 +408,4 @@ sys_pipe(void) 129 | fd[1] = fd1; 130 | return 0; 131 | } 132 | + 133 | diff -r f8a4e40ab1d6 user.h 134 | --- a/user.h Thu Aug 30 14:32:06 2007 -0400 135 | +++ b/user.h Thu Aug 30 13:02:34 2007 -0400 136 | @@ -21,6 +21,7 @@ int getpid(); 137 | int getpid(); 138 | char* sbrk(int); 139 | int sleep(int); 140 | +int symlink(int); 141 | 142 | // ulib.c 143 | int stat(char*, struct stat*); 144 | diff -r f8a4e40ab1d6 usys.S 145 | --- a/usys.S Thu Aug 30 14:32:06 2007 -0400 146 | +++ b/usys.S Thu Aug 30 13:05:54 2007 -0400 147 | @@ -28,3 +28,4 @@ STUB(getpid) 148 | STUB(getpid) 149 | STUB(sbrk) 150 | STUB(sleep) 151 | +STUB(symlink) 152 | -------------------------------------------------------------------------------- /code/Notes: -------------------------------------------------------------------------------- 1 | bochs 2.2.6: 2 | ./configure --enable-smp --enable-disasm --enable-debugger --enable-all-optimizations --enable-4meg-pages --enable-global-pages --enable-pae --disable-reset-on-triple-fault 3 | bochs CVS after 2.2.6: 4 | ./configure --enable-smp --enable-disasm --enable-debugger --enable-all-optimizations --enable-4meg-pages --enable-global-pages --enable-pae 5 | 6 | bootmain.c doesn't work right if the ELF sections aren't 7 | sector-aligned. so you can't use ld -N. and the sections may also need 8 | to be non-zero length, only really matters for tiny "kernels". 9 | 10 | kernel loaded at 1 megabyte. stack same place that bootasm.S left it. 11 | 12 | kinit() should find real mem size 13 | and rescue useable memory below 1 meg 14 | 15 | no paging, no use of page table hardware, just segments 16 | 17 | no user area: no magic kernel stack mapping 18 | so no copying of kernel stack during fork 19 | though there is a kernel stack page for each process 20 | 21 | no kernel malloc(), just kalloc() for user core 22 | 23 | user pointers aren't valid in the kernel 24 | 25 | are interrupts turned on in the kernel? yes. 26 | 27 | pass curproc explicitly, or implicit from cpu #? 28 | e.g. argument to newproc()? 29 | hmm, you need a global curproc[cpu] for trap() &c 30 | 31 | no stack expansion 32 | 33 | test running out of memory, process slots 34 | 35 | we can't really use a separate stack segment, since stack addresses 36 | need to work correctly as ordinary pointers. the same may be true of 37 | data vs text. how can we have a gap between data and stack, so that 38 | both can grow, without committing 4GB of physical memory? does this 39 | mean we need paging? 40 | 41 | perhaps have fixed-size stack, put it in the data segment? 42 | 43 | oops, if kernel stack is in contiguous user phys mem, then moving 44 | users' memory (e.g. to expand it) will wreck any pointers into the 45 | kernel stack. 46 | 47 | do we need to set fs and gs? so user processes can't abuse them? 48 | 49 | setupsegs() may modify current segment table, is that legal? 50 | 51 | trap() ought to lgdt on return, since currently only done in swtch() 52 | 53 | protect hardware interrupt vectors from user INT instructions? 54 | 55 | test out-of-fd cases for creating pipe. 56 | test pipe reader closes then write 57 | test two readers, two writers. 58 | test children being inherited by grandparent &c 59 | 60 | some sleep()s should be interruptible by kill() 61 | 62 | locks 63 | init_lock 64 | sequences CPU startup 65 | proc_table_lock 66 | also protects next_pid 67 | per-fd lock *just* protects count read-modify-write 68 | also maybe freeness? 69 | memory allocator 70 | printf 71 | 72 | in general, the table locks protect both free-ness and 73 | public variables of table elements 74 | in many cases you can use table elements w/o a lock 75 | e.g. if you are the process, or you are using an fd 76 | 77 | lock order 78 | per-pipe lock 79 | proc_table_lock fd_table_lock kalloc_lock 80 | console_lock 81 | 82 | do you have to be holding the mutex in order to call wakeup()? yes 83 | 84 | device interrupts don't clear FL_IF 85 | so a recursive timer interrupt is possible 86 | 87 | what does inode->busy mean? 88 | might be held across disk reads 89 | no-one is allowed to do anything to the inode 90 | protected by inode_table_lock 91 | inode->count counts in-memory pointers to the struct 92 | prevents inode[] element from being re-used 93 | protected by inode_table_lock 94 | 95 | blocks and inodes have ad-hoc sleep-locks 96 | provide a single mechanism? 97 | 98 | kalloc() can return 0; do callers handle this right? 99 | 100 | test: one process unlinks a file while another links to it 101 | test: one process opens a file while another deletes it 102 | test: deadlock d/.. vs ../d, two processes. 103 | test: dup() shared fd->off 104 | test: does echo foo > x truncate x? 105 | 106 | sh: ioredirection incorrect now we have pipes 107 | sh: chain of pipes won't work, also ugly that parent closes fdarray entries too 108 | sh: dynamic memory allocation? 109 | sh: should sh support ; () & 110 | sh: stop stdin on ctrl-d (for cat > y) 111 | 112 | really should have bdwrite() for file content 113 | and make some inode updates async 114 | so soft updates make sense 115 | 116 | disk scheduling 117 | echo foo > bar should truncate bar 118 | so O_CREATE should not truncate 119 | but O_TRUNC should 120 | 121 | make it work on a real machine 122 | release before acquire at end of sleep? 123 | check 2nd disk (i.e. if not in .bochsrc) 124 | -------------------------------------------------------------------------------- /code/TRICKS: -------------------------------------------------------------------------------- 1 | This file lists subtle things that might not be commented 2 | as well as they should be in the source code and that 3 | might be worth pointing out in a longer explanation or in class. 4 | 5 | --- 6 | 7 | [2009/07/12: No longer relevant; forkret1 changed 8 | and this is now cleaner.] 9 | 10 | forkret1 in trapasm.S is called with a tf argument. 11 | In order to use it, forkret1 copies the tf pointer into 12 | %esp and then jumps to trapret, which pops the 13 | register state out of the trap frame. If an interrupt 14 | came in between the mov tf, %esp and the iret that 15 | goes back out to user space, the interrupt stack frame 16 | would end up scribbling over the tf and whatever memory 17 | lay under it. 18 | 19 | Why is this safe? Because forkret1 is only called 20 | the first time a process returns to user space, and 21 | at that point, cp->tf is set to point to a trap frame 22 | constructed at the top of cp's kernel stack. So tf 23 | *is* a valid %esp that can hold interrupt state. 24 | 25 | If other tf's were used in forkret1, we could add 26 | a cli before the mov tf, %esp. 27 | 28 | --- 29 | 30 | In pushcli, must cli() no matter what. It is not safe to do 31 | 32 | if(cpus[cpu()].ncli == 0) 33 | cli(); 34 | cpus[cpu()].ncli++; 35 | 36 | because if interrupts are off then we might call cpu(), get 37 | rescheduled to a different cpu, look at cpus[oldcpu].ncli, 38 | and wrongly decide not to disable interrupts on the new cpu. 39 | 40 | Instead do 41 | 42 | cli(); 43 | cpus[cpu()].ncli++; 44 | 45 | always. 46 | 47 | --- 48 | 49 | There is a (harmless) race in pushcli, which does 50 | 51 | eflags = readeflags(); 52 | cli(); 53 | if(c->ncli++ == 0) 54 | c->intena = eflags & FL_IF; 55 | 56 | Consider a bottom-level pushcli. 57 | If interrupts are disabled already, then the right thing 58 | happens: read_eflags finds that FL_IF is not set, 59 | and intena = 0. If interrupts are enabled, then 60 | it is less clear that the right thing happens: 61 | the readeflags can execute, then the process 62 | can get preempted and rescheduled on another cpu, 63 | and then once it starts running, perhaps with 64 | interrupts disabled (can happen since the scheduler 65 | only enables interrupts once per scheduling loop, 66 | not every time it schedules a process), it will 67 | incorrectly record that interrupts *were* enabled. 68 | This doesn't matter, because if it was safe to be 69 | running with interrupts enabled before the context 70 | switch, it is still safe (and arguably more correct) 71 | to run with them enabled after the context switch too. 72 | 73 | In fact it would be safe if scheduler always set 74 | c->intena = 1; 75 | before calling swtch, and perhaps it should. 76 | 77 | --- 78 | 79 | The x86's processor-ordering memory model 80 | matches spin locks well, so no explicit memory 81 | synchronization instructions are required in 82 | acquire and release. 83 | 84 | Consider two sequences of code on different CPUs: 85 | 86 | CPU0 87 | A; 88 | release(lk); 89 | 90 | and 91 | 92 | CPU1 93 | acquire(lk); 94 | B; 95 | 96 | We want to make sure that: 97 | - all reads in B see the effects of writes in A. 98 | - all reads in A do *not* see the effects of writes in B. 99 | 100 | The x86 guarantees that writes in A will go out 101 | to memory before the write of lk->locked = 0 in 102 | release(lk). It further guarantees that CPU1 103 | will observe CPU0's write of lk->locked = 0 only 104 | after observing the earlier writes by CPU0. 105 | So any reads in B are guaranteed to observe the 106 | effects of writes in A. 107 | 108 | According to the Intel manual behavior spec, the 109 | second condition requires a serialization instruction 110 | in release, to avoid reads in A happening after giving 111 | up lk. No Intel SMP processor in existence actually 112 | moves reads down after writes, but the language in 113 | the spec allows it. There is no telling whether future 114 | processors will need it. 115 | 116 | --- 117 | 118 | The code in fork needs to read np->pid before 119 | setting np->state to RUNNABLE. The following 120 | is not a correct way to do this: 121 | 122 | int 123 | fork(void) 124 | { 125 | ... 126 | np->state = RUNNABLE; 127 | return np->pid; // oops 128 | } 129 | 130 | After setting np->state to RUNNABLE, some other CPU 131 | might run the process, it might exit, and then it might 132 | get reused for a different process (with a new pid), all 133 | before the return statement. So it's not safe to just 134 | "return np->pid". Even saving a copy of np->pid before 135 | setting np->state isn't safe, since the compiler is 136 | allowed to re-order statements. 137 | 138 | The real code saves a copy of np->pid, then acquires a lock 139 | around the write to np->state. The acquire() prevents the 140 | compiler from re-ordering. 141 | -------------------------------------------------------------------------------- /code/runoff: -------------------------------------------------------------------------------- 1 | #!/bin/sh 2 | 3 | echo This script takes a minute to run. Be patient. 1>&2 4 | 5 | LC_CTYPE=C export LC_CTYPE 6 | 7 | # pad stdin to multiple of 120 lines 8 | pad() 9 | { 10 | awk '{print} END{for(; NR%120!=0; NR++) print ""}' 11 | } 12 | 13 | # create formatted (numbered) files 14 | mkdir -p fmt 15 | rm -f fmt/* 16 | cp README fmt 17 | files=`grep -v '^#' runoff.list | awk '{print $1}'` 18 | n=99 19 | for i in $files 20 | do 21 | ./runoff1 -n $n $i >fmt/$i 22 | nn=`tail -1 fmt/$i | sed 's/ .*//; s/^0*//'` 23 | if [ "x$nn" != x ]; then 24 | n=$nn 25 | fi 26 | done 27 | 28 | # create table of contents 29 | cat toc.hdr >fmt/toc 30 | pr -e8 -t runoff.list | awk ' 31 | /^[a-z0-9]/ { 32 | s=$0 33 | f="fmt/"$1 34 | getline"fmt/tocdata" 39 | next 40 | } 41 | { 42 | print 43 | }' | pr -3 -t >>fmt/toc 44 | cat toc.ftr >>fmt/toc 45 | 46 | # check for bad alignments 47 | perl -e ' 48 | $leftwarn = 0; 49 | while(<>){ 50 | chomp; 51 | s!#.*!!; 52 | s!\s+! !g; 53 | s! +$!!; 54 | next if /^$/; 55 | 56 | if(/TOC: (\d+) (.*)/){ 57 | $toc{$2} = $1; 58 | next; 59 | } 60 | 61 | if(/sheet1: (left|right)$/){ 62 | print STDERR "assuming that sheet 1 is a $1 page. double-check!\n"; 63 | $left = $1 eq "left" ? "13579" : "02468"; 64 | $right = $1 eq "left" ? "02468" : "13579"; 65 | next; 66 | } 67 | 68 | if(/even: (.*)/){ 69 | $file = $1; 70 | if(!defined($toc{$file})){ 71 | print STDERR "Have no toc for $file\n"; 72 | next; 73 | } 74 | if($toc{$file} =~ /^\d\d[^0]/){ 75 | print STDERR "$file does not start on a fresh page.\n"; 76 | } 77 | next; 78 | } 79 | 80 | if(/odd: (.*)/){ 81 | $file = $1; 82 | if(!defined($toc{$file})){ 83 | print STDERR "Have no toc for $file\n"; 84 | next; 85 | } 86 | if($toc{$file} !~ /^\d\d5/){ 87 | print STDERR "$file does not start on a second half page.\n"; 88 | } 89 | next; 90 | } 91 | 92 | if(/(left|right): (.*)/){ 93 | $what = $1; 94 | $file = $2; 95 | if(!defined($toc{$file})){ 96 | print STDERR "Have no toc for $file\n"; 97 | next; 98 | } 99 | if($what eq "left" && !($toc{$file} =~ /^\d[$left][05]/)){ 100 | print STDERR "$file does not start on a left page [$toc{$file}]\n"; 101 | } 102 | # why does this not work if I inline $x in the if? 103 | $x = ($toc{$file} =~ /^\d[$right][05]/); 104 | if($what eq "right" && !$x){ 105 | print STDERR "$file does not start on a right page [$toc{$file}] [$x]\n"; 106 | } 107 | next; 108 | } 109 | 110 | print STDERR "Unknown spec: $_\n"; 111 | } 112 | ' fmt/tocdata runoff.spec 113 | 114 | # make definition list 115 | cd fmt 116 | perl -e ' 117 | while(<>) { 118 | chomp; 119 | 120 | s!//.*!!; 121 | s!/\*([^*]|[*][^/])*\*/!!g; 122 | s!\s! !g; 123 | s! +$!!; 124 | 125 | # look for declarations like char* x; 126 | if (/^[0-9]+ typedef .* u(int|short|long|char);/) { 127 | next; 128 | } 129 | if (/^[0-9]+ extern/) { 130 | next; 131 | } 132 | if (/^[0-9]+ struct [a-zA-Z0-9_]+;/) { 133 | next; 134 | } 135 | if (/^([0-9]+) #define +([A-za-z0-9_]+) +?\(.*/) { 136 | print "$1 $2\n" 137 | } 138 | elsif (/^([0-9]+) #define +([A-Za-z0-9_]+) +([^ ]+)/) { 139 | print "$1 $2 $3\n"; 140 | } 141 | elsif (/^([0-9]+) #define +([A-Za-z0-9_]+)/) { 142 | print "$1 $2\n"; 143 | } 144 | 145 | if(/^^([0-9]+) \.globl ([a-zA-Z0-9_]+)/){ 146 | $isglobl{$2} = 1; 147 | } 148 | if(/^^([0-9]+) ([a-zA-Z0-9_]+):$/ && $isglobl{$2}){ 149 | print "$1 $2\n"; 150 | } 151 | 152 | if (/\(/) { 153 | next; 154 | } 155 | 156 | if (/^([0-9]+) (((static|struct|extern|union|enum) +)*([A-Za-z0-9_]+))( .*)? +([A-Za-z_][A-Za-z0-9_]*)(,|;|=| =)/) { 157 | print "$1 $7\n"; 158 | } 159 | 160 | elsif(/^([0-9]+) (enum|struct|union) +([A-Za-z0-9_]+) +{/){ 161 | print "$1 $3\n"; 162 | } 163 | # TODO: enum members 164 | } 165 | ' $files >defs 166 | 167 | (for i in $files 168 | do 169 | case "$i" in 170 | *.S) 171 | cat $i | sed 's;#.*;;; s;//.*;;;' 172 | ;; 173 | *) 174 | cat $i | sed 's;//.*;;; s;"([^"\\]|\\.)*";;;' 175 | esac 176 | done 177 | ) >alltext 178 | 179 | perl -n -e 'print if s/^([0-9]+ [a-zA-Z0-9_]+)\(.*$/\1/;' alltext | 180 | egrep -v ' (STUB|usage|main|if|for)$' >>defs 181 | #perl -n -e 'print if s/^([0-9]+) STUB\(([a-zA-Z0-9_]+)\)$/\1 \2/;' alltext \ 182 | # >>defs 183 | ( 184 | >s.defs 185 | 186 | # make reference list 187 | for i in `awk '{print $2}' defs | sort -f | uniq` 188 | do 189 | defs=`egrep '^[0-9]+ '$i'( |$)' defs | awk '{print $1}'` 190 | echo $i $defs >>s.defs 191 | uses=`egrep -h '([^a-zA-Z_0-9])'$i'($|[^a-zA-Z_0-9])' alltext | awk '{print $1}'` 192 | if [ "x$defs" != "x$uses" ]; then 193 | echo $i $defs 194 | echo $uses |fmt -29 | sed 's/^/ /' 195 | # else 196 | # echo $i defined but not used >&2 197 | fi 198 | done 199 | ) >refs 200 | 201 | # build defs list 202 | awk ' 203 | { 204 | printf("%04d %s\n", $2, $1); 205 | for(i=3; i<=NF; i++) 206 | printf("%04d \" \n", $i); 207 | } 208 | ' s.defs > t.defs 209 | 210 | # format the whole thing 211 | ( 212 | ../pr.pl README 213 | ../pr.pl -h "table of contents" toc 214 | # pr -t -2 t.defs | ../pr.pl -h "definitions" | pad 215 | pr -t -l50 -2 refs | ../pr.pl -h "cross-references" | pad 216 | # pr.pl -h "definitions" -2 t.defs | pad 217 | # pr.pl -h "cross-references" -2 refs | pad 218 | for i in $files 219 | do 220 | ../pr.pl -h "xv6/$i" $i 221 | done 222 | ) | mpage -m50t50b -o -bLetter -T -t -2 -FCourier -L60 >all.ps 223 | grep Pages: all.ps 224 | 225 | # if we have the nice font, use it 226 | nicefont=LucidaSans-Typewriter83 227 | if [ ! -f ../$nicefont ] 228 | then 229 | if git cat-file blob font:$nicefont > ../$nicefont~; then 230 | mv ../$nicefont~ ../$nicefont 231 | fi 232 | fi 233 | if [ -f ../$nicefont ] 234 | then 235 | echo nicefont 236 | (sed 1q all.ps; cat ../$nicefont; sed "1d; s/Courier/$nicefont/" all.ps) >allf.ps 237 | else 238 | echo ugly font! 239 | cp all.ps allf.ps 240 | fi 241 | ps2pdf allf.ps ../xv6.pdf 242 | # cd .. 243 | # pdftops xv6.pdf xv6.ps 244 | -------------------------------------------------------------------------------- /code/defs.h: -------------------------------------------------------------------------------- 1 | struct buf; 2 | struct context; 3 | struct file; 4 | struct inode; 5 | struct pipe; 6 | struct proc; 7 | struct rtcdate; 8 | struct spinlock; 9 | struct sleeplock; 10 | struct stat; 11 | struct superblock; 12 | 13 | // bio.c 14 | void binit(void); 15 | struct buf* bread(uint, uint); 16 | void brelse(struct buf*); 17 | void bwrite(struct buf*); 18 | 19 | // console.c 20 | void consoleinit(void); 21 | void cprintf(char*, ...); 22 | void consoleintr(int(*)(void)); 23 | void panic(char*) __attribute__((noreturn)); 24 | 25 | // exec.c 26 | int exec(char*, char**); 27 | 28 | // file.c 29 | struct file* filealloc(void); 30 | void fileclose(struct file*); 31 | struct file* filedup(struct file*); 32 | void fileinit(void); 33 | int fileread(struct file*, char*, int n); 34 | int filestat(struct file*, struct stat*); 35 | int filewrite(struct file*, char*, int n); 36 | 37 | // fs.c 38 | void readsb(int dev, struct superblock *sb); 39 | int dirlink(struct inode*, char*, uint); 40 | struct inode* dirlookup(struct inode*, char*, uint*); 41 | struct inode* ialloc(uint, short); 42 | struct inode* idup(struct inode*); 43 | void iinit(int dev); 44 | void ilock(struct inode*); 45 | void iput(struct inode*); 46 | void iunlock(struct inode*); 47 | void iunlockput(struct inode*); 48 | void iupdate(struct inode*); 49 | int namecmp(const char*, const char*); 50 | struct inode* namei(char*); 51 | struct inode* nameiparent(char*, char*); 52 | int readi(struct inode*, char*, uint, uint); 53 | void stati(struct inode*, struct stat*); 54 | int writei(struct inode*, char*, uint, uint); 55 | 56 | // ide.c 57 | void ideinit(void); 58 | void ideintr(void); 59 | void iderw(struct buf*); 60 | 61 | // ioapic.c 62 | void ioapicenable(int irq, int cpu); 63 | extern uchar ioapicid; 64 | void ioapicinit(void); 65 | 66 | // kalloc.c 67 | char* kalloc(void); 68 | void kfree(char*); 69 | void kinit1(void*, void*); 70 | void kinit2(void*, void*); 71 | 72 | // kbd.c 73 | void kbdintr(void); 74 | 75 | // lapic.c 76 | void cmostime(struct rtcdate *r); 77 | int lapicid(void); 78 | extern volatile uint* lapic; 79 | void lapiceoi(void); 80 | void lapicinit(void); 81 | void lapicstartap(uchar, uint); 82 | void microdelay(int); 83 | 84 | // log.c 85 | void initlog(int dev); 86 | void log_write(struct buf*); 87 | void begin_op(); 88 | void end_op(); 89 | 90 | // mp.c 91 | extern int ismp; 92 | void mpinit(void); 93 | 94 | // picirq.c 95 | void picenable(int); 96 | void picinit(void); 97 | 98 | // pipe.c 99 | int pipealloc(struct file**, struct file**); 100 | void pipeclose(struct pipe*, int); 101 | int piperead(struct pipe*, char*, int); 102 | int pipewrite(struct pipe*, char*, int); 103 | 104 | //PAGEBREAK: 16 105 | // proc.c 106 | int cpuid(void); 107 | void exit(void); 108 | int fork(void); 109 | int growproc(int); 110 | int kill(int); 111 | struct cpu* mycpu(void); 112 | struct proc* myproc(); 113 | void pinit(void); 114 | void procdump(void); 115 | void scheduler(void) __attribute__((noreturn)); 116 | void sched(void); 117 | void setproc(struct proc*); 118 | void sleep(void*, struct spinlock*); 119 | void userinit(void); 120 | int wait(void); 121 | void wakeup(void*); 122 | void yield(void); 123 | 124 | // swtch.S 125 | void swtch(struct context**, struct context*); 126 | 127 | // spinlock.c 128 | void acquire(struct spinlock*); 129 | void getcallerpcs(void*, uint*); 130 | int holding(struct spinlock*); 131 | void initlock(struct spinlock*, char*); 132 | void release(struct spinlock*); 133 | void pushcli(void); 134 | void popcli(void); 135 | 136 | // sleeplock.c 137 | void acquiresleep(struct sleeplock*); 138 | void releasesleep(struct sleeplock*); 139 | int holdingsleep(struct sleeplock*); 140 | void initsleeplock(struct sleeplock*, char*); 141 | 142 | // string.c 143 | int memcmp(const void*, const void*, uint); 144 | void* memmove(void*, const void*, uint); 145 | void* memset(void*, int, uint); 146 | char* safestrcpy(char*, const char*, int); 147 | int strlen(const char*); 148 | int strncmp(const char*, const char*, uint); 149 | char* strncpy(char*, const char*, int); 150 | 151 | // syscall.c 152 | int argint(int, int*); 153 | int argptr(int, char**, int); 154 | int argstr(int, char**); 155 | int fetchint(uint, int*); 156 | int fetchstr(uint, char**); 157 | void syscall(void); 158 | 159 | // timer.c 160 | void timerinit(void); 161 | 162 | // trap.c 163 | void idtinit(void); 164 | extern uint ticks; 165 | void tvinit(void); 166 | extern struct spinlock tickslock; 167 | 168 | // uart.c 169 | void uartinit(void); 170 | void uartintr(void); 171 | void uartputc(int); 172 | 173 | // vm.c 174 | void seginit(void); 175 | void kvmalloc(void); 176 | pde_t* setupkvm(void); 177 | char* uva2ka(pde_t*, char*); 178 | int allocuvm(pde_t*, uint, uint); 179 | int deallocuvm(pde_t*, uint, uint); 180 | void freevm(pde_t*); 181 | void inituvm(pde_t*, char*, uint); 182 | int loaduvm(pde_t*, char*, struct inode*, uint, uint); 183 | pde_t* copyuvm(pde_t*, uint); 184 | void switchuvm(struct proc*); 185 | void switchkvm(void); 186 | int copyout(pde_t*, uint, void*, uint); 187 | void clearpteu(pde_t *pgdir, char *uva); 188 | 189 | // number of elements in fixed-size array 190 | #define NELEM(x) (sizeof(x)/sizeof((x)[0])) 191 | -------------------------------------------------------------------------------- /code/log.c: -------------------------------------------------------------------------------- 1 | #include "types.h" 2 | #include "defs.h" 3 | #include "param.h" 4 | #include "spinlock.h" 5 | #include "sleeplock.h" 6 | #include "fs.h" 7 | #include "buf.h" 8 | 9 | // Simple logging that allows concurrent FS system calls. 10 | // 11 | // A log transaction contains the updates of multiple FS system 12 | // calls. The logging system only commits when there are 13 | // no FS system calls active. Thus there is never 14 | // any reasoning required about whether a commit might 15 | // write an uncommitted system call's updates to disk. 16 | // 17 | // A system call should call begin_op()/end_op() to mark 18 | // its start and end. Usually begin_op() just increments 19 | // the count of in-progress FS system calls and returns. 20 | // But if it thinks the log is close to running out, it 21 | // sleeps until the last outstanding end_op() commits. 22 | // 23 | // The log is a physical re-do log containing disk blocks. 24 | // The on-disk log format: 25 | // header block, containing block #s for block A, B, C, ... 26 | // block A 27 | // block B 28 | // block C 29 | // ... 30 | // Log appends are synchronous. 31 | 32 | // Contents of the header block, used for both the on-disk header block 33 | // and to keep track in memory of logged block# before commit. 34 | struct logheader { 35 | int n; 36 | int block[LOGSIZE]; 37 | }; 38 | 39 | struct log { 40 | struct spinlock lock; 41 | int start; 42 | int size; 43 | int outstanding; // how many FS sys calls are executing. 44 | int committing; // in commit(), please wait. 45 | int dev; 46 | struct logheader lh; 47 | }; 48 | struct log log; 49 | 50 | static void recover_from_log(void); 51 | static void commit(); 52 | 53 | void 54 | initlog(int dev) 55 | { 56 | if (sizeof(struct logheader) >= BSIZE) 57 | panic("initlog: too big logheader"); 58 | 59 | struct superblock sb; 60 | initlock(&log.lock, "log"); 61 | readsb(dev, &sb); 62 | log.start = sb.logstart; 63 | log.size = sb.nlog; 64 | log.dev = dev; 65 | recover_from_log(); 66 | } 67 | 68 | // Copy committed blocks from log to their home location 69 | static void 70 | install_trans(void) 71 | { 72 | int tail; 73 | 74 | for (tail = 0; tail < log.lh.n; tail++) { 75 | struct buf *lbuf = bread(log.dev, log.start+tail+1); // read log block 76 | struct buf *dbuf = bread(log.dev, log.lh.block[tail]); // read dst 77 | memmove(dbuf->data, lbuf->data, BSIZE); // copy block to dst 78 | bwrite(dbuf); // write dst to disk 79 | brelse(lbuf); 80 | brelse(dbuf); 81 | } 82 | } 83 | 84 | // Read the log header from disk into the in-memory log header 85 | static void 86 | read_head(void) 87 | { 88 | struct buf *buf = bread(log.dev, log.start); 89 | struct logheader *lh = (struct logheader *) (buf->data); 90 | int i; 91 | log.lh.n = lh->n; 92 | for (i = 0; i < log.lh.n; i++) { 93 | log.lh.block[i] = lh->block[i]; 94 | } 95 | brelse(buf); 96 | } 97 | 98 | // Write in-memory log header to disk. 99 | // This is the true point at which the 100 | // current transaction commits. 101 | static void 102 | write_head(void) 103 | { 104 | struct buf *buf = bread(log.dev, log.start); 105 | struct logheader *hb = (struct logheader *) (buf->data); 106 | int i; 107 | hb->n = log.lh.n; 108 | for (i = 0; i < log.lh.n; i++) { 109 | hb->block[i] = log.lh.block[i]; 110 | } 111 | bwrite(buf); 112 | brelse(buf); 113 | } 114 | 115 | static void 116 | recover_from_log(void) 117 | { 118 | read_head(); 119 | install_trans(); // if committed, copy from log to disk 120 | log.lh.n = 0; 121 | write_head(); // clear the log 122 | } 123 | 124 | // called at the start of each FS system call. 125 | void 126 | begin_op(void) 127 | { 128 | acquire(&log.lock); 129 | while(1){ 130 | if(log.committing){ 131 | sleep(&log, &log.lock); 132 | } else if(log.lh.n + (log.outstanding+1)*MAXOPBLOCKS > LOGSIZE){ 133 | // this op might exhaust log space; wait for commit. 134 | sleep(&log, &log.lock); 135 | } else { 136 | log.outstanding += 1; 137 | release(&log.lock); 138 | break; 139 | } 140 | } 141 | } 142 | 143 | // called at the end of each FS system call. 144 | // commits if this was the last outstanding operation. 145 | void 146 | end_op(void) 147 | { 148 | int do_commit = 0; 149 | 150 | acquire(&log.lock); 151 | log.outstanding -= 1; 152 | if(log.committing) 153 | panic("log.committing"); 154 | if(log.outstanding == 0){ 155 | do_commit = 1; 156 | log.committing = 1; 157 | } else { 158 | // begin_op() may be waiting for log space, 159 | // and decrementing log.outstanding has decreased 160 | // the amount of reserved space. 161 | wakeup(&log); 162 | } 163 | release(&log.lock); 164 | 165 | if(do_commit){ 166 | // call commit w/o holding locks, since not allowed 167 | // to sleep with locks. 168 | commit(); 169 | acquire(&log.lock); 170 | log.committing = 0; 171 | wakeup(&log); 172 | release(&log.lock); 173 | } 174 | } 175 | 176 | // Copy modified blocks from cache to log. 177 | static void 178 | write_log(void) 179 | { 180 | int tail; 181 | 182 | for (tail = 0; tail < log.lh.n; tail++) { 183 | struct buf *to = bread(log.dev, log.start+tail+1); // log block 184 | struct buf *from = bread(log.dev, log.lh.block[tail]); // cache block 185 | memmove(to->data, from->data, BSIZE); 186 | bwrite(to); // write the log 187 | brelse(from); 188 | brelse(to); 189 | } 190 | } 191 | 192 | static void 193 | commit() 194 | { 195 | if (log.lh.n > 0) { 196 | write_log(); // Write modified blocks from cache to log 197 | write_head(); // Write header to disk -- the real commit 198 | install_trans(); // Now install writes to home locations 199 | log.lh.n = 0; 200 | write_head(); // Erase the transaction from the log 201 | } 202 | } 203 | 204 | // Caller has modified b->data and is done with the buffer. 205 | // Record the block number and pin in the cache with B_DIRTY. 206 | // commit()/write_log() will do the disk write. 207 | // 208 | // log_write() replaces bwrite(); a typical use is: 209 | // bp = bread(...) 210 | // modify bp->data[] 211 | // log_write(bp) 212 | // brelse(bp) 213 | void 214 | log_write(struct buf *b) 215 | { 216 | int i; 217 | 218 | if (log.lh.n >= LOGSIZE || log.lh.n >= log.size - 1) 219 | panic("too big a transaction"); 220 | if (log.outstanding < 1) 221 | panic("log_write outside of trans"); 222 | 223 | acquire(&log.lock); 224 | for (i = 0; i < log.lh.n; i++) { 225 | if (log.lh.block[i] == b->blockno) // log absorbtion 226 | break; 227 | } 228 | log.lh.block[i] = b->blockno; 229 | if (i == log.lh.n) 230 | log.lh.n++; 231 | b->flags |= B_DIRTY; // prevent eviction 232 | release(&log.lock); 233 | } 234 | 235 | -------------------------------------------------------------------------------- /code/console.c: -------------------------------------------------------------------------------- 1 | // Console input and output. 2 | // Input is from the keyboard or serial port. 3 | // Output is written to the screen and serial port. 4 | 5 | #include "types.h" 6 | #include "defs.h" 7 | #include "param.h" 8 | #include "traps.h" 9 | #include "spinlock.h" 10 | #include "sleeplock.h" 11 | #include "fs.h" 12 | #include "file.h" 13 | #include "memlayout.h" 14 | #include "mmu.h" 15 | #include "proc.h" 16 | #include "x86.h" 17 | 18 | static void consputc(int); 19 | 20 | static int panicked = 0; 21 | 22 | static struct { 23 | struct spinlock lock; 24 | int locking; 25 | } cons; 26 | 27 | static void 28 | printint(int xx, int base, int sign) 29 | { 30 | static char digits[] = "0123456789abcdef"; 31 | char buf[16]; 32 | int i; 33 | uint x; 34 | 35 | if(sign && (sign = xx < 0)) 36 | x = -xx; 37 | else 38 | x = xx; 39 | 40 | i = 0; 41 | do{ 42 | buf[i++] = digits[x % base]; 43 | }while((x /= base) != 0); 44 | 45 | if(sign) 46 | buf[i++] = '-'; 47 | 48 | while(--i >= 0) 49 | consputc(buf[i]); 50 | } 51 | //PAGEBREAK: 50 52 | 53 | // Print to the console. only understands %d, %x, %p, %s. 54 | void 55 | cprintf(char *fmt, ...) 56 | { 57 | int i, c, locking; 58 | uint *argp; 59 | char *s; 60 | 61 | locking = cons.locking; 62 | if(locking) 63 | acquire(&cons.lock); 64 | 65 | if (fmt == 0) 66 | panic("null fmt"); 67 | 68 | argp = (uint*)(void*)(&fmt + 1); 69 | for(i = 0; (c = fmt[i] & 0xff) != 0; i++){ 70 | if(c != '%'){ 71 | consputc(c); 72 | continue; 73 | } 74 | c = fmt[++i] & 0xff; 75 | if(c == 0) 76 | break; 77 | switch(c){ 78 | case 'd': 79 | printint(*argp++, 10, 1); 80 | break; 81 | case 'x': 82 | case 'p': 83 | printint(*argp++, 16, 0); 84 | break; 85 | case 's': 86 | if((s = (char*)*argp++) == 0) 87 | s = "(null)"; 88 | for(; *s; s++) 89 | consputc(*s); 90 | break; 91 | case '%': 92 | consputc('%'); 93 | break; 94 | default: 95 | // Print unknown % sequence to draw attention. 96 | consputc('%'); 97 | consputc(c); 98 | break; 99 | } 100 | } 101 | 102 | if(locking) 103 | release(&cons.lock); 104 | } 105 | 106 | void 107 | panic(char *s) 108 | { 109 | int i; 110 | uint pcs[10]; 111 | 112 | cli(); 113 | cons.locking = 0; 114 | // use lapiccpunum so that we can call panic from mycpu() 115 | cprintf("lapicid %d: panic: ", lapicid()); 116 | cprintf(s); 117 | cprintf("\n"); 118 | getcallerpcs(&s, pcs); 119 | for(i=0; i<10; i++) 120 | cprintf(" %p", pcs[i]); 121 | panicked = 1; // freeze other CPU 122 | for(;;) 123 | ; 124 | } 125 | 126 | //PAGEBREAK: 50 127 | #define BACKSPACE 0x100 128 | #define CRTPORT 0x3d4 129 | static ushort *crt = (ushort*)P2V(0xb8000); // CGA memory 130 | 131 | static void 132 | cgaputc(int c) 133 | { 134 | int pos; 135 | 136 | // Cursor position: col + 80*row. 137 | outb(CRTPORT, 14); 138 | pos = inb(CRTPORT+1) << 8; 139 | outb(CRTPORT, 15); 140 | pos |= inb(CRTPORT+1); 141 | 142 | if(c == '\n') 143 | pos += 80 - pos%80; 144 | else if(c == BACKSPACE){ 145 | if(pos > 0) --pos; 146 | } else 147 | crt[pos++] = (c&0xff) | 0x0700; // black on white 148 | 149 | if(pos < 0 || pos > 25*80) 150 | panic("pos under/overflow"); 151 | 152 | if((pos/80) >= 24){ // Scroll up. 153 | memmove(crt, crt+80, sizeof(crt[0])*23*80); 154 | pos -= 80; 155 | memset(crt+pos, 0, sizeof(crt[0])*(24*80 - pos)); 156 | } 157 | 158 | outb(CRTPORT, 14); 159 | outb(CRTPORT+1, pos>>8); 160 | outb(CRTPORT, 15); 161 | outb(CRTPORT+1, pos); 162 | crt[pos] = ' ' | 0x0700; 163 | } 164 | 165 | void 166 | consputc(int c) 167 | { 168 | if(panicked){ 169 | cli(); 170 | for(;;) 171 | ; 172 | } 173 | 174 | if(c == BACKSPACE){ 175 | uartputc('\b'); uartputc(' '); uartputc('\b'); 176 | } else 177 | uartputc(c); 178 | cgaputc(c); 179 | } 180 | 181 | #define INPUT_BUF 128 182 | struct { 183 | char buf[INPUT_BUF]; 184 | uint r; // Read index 185 | uint w; // Write index 186 | uint e; // Edit index 187 | } input; 188 | 189 | #define C(x) ((x)-'@') // Control-x 190 | 191 | void 192 | consoleintr(int (*getc)(void)) 193 | { 194 | int c, doprocdump = 0; 195 | 196 | acquire(&cons.lock); 197 | while((c = getc()) >= 0){ 198 | switch(c){ 199 | case C('P'): // Process listing. 200 | // procdump() locks cons.lock indirectly; invoke later 201 | doprocdump = 1; 202 | break; 203 | case C('U'): // Kill line. 204 | while(input.e != input.w && 205 | input.buf[(input.e-1) % INPUT_BUF] != '\n'){ 206 | input.e--; 207 | consputc(BACKSPACE); 208 | } 209 | break; 210 | case C('H'): case '\x7f': // Backspace 211 | if(input.e != input.w){ 212 | input.e--; 213 | consputc(BACKSPACE); 214 | } 215 | break; 216 | default: 217 | if(c != 0 && input.e-input.r < INPUT_BUF){ 218 | c = (c == '\r') ? '\n' : c; 219 | input.buf[input.e++ % INPUT_BUF] = c; 220 | consputc(c); 221 | if(c == '\n' || c == C('D') || input.e == input.r+INPUT_BUF){ 222 | input.w = input.e; 223 | wakeup(&input.r); 224 | } 225 | } 226 | break; 227 | } 228 | } 229 | release(&cons.lock); 230 | if(doprocdump) { 231 | procdump(); // now call procdump() wo. cons.lock held 232 | } 233 | } 234 | 235 | int 236 | consoleread(struct inode *ip, char *dst, int n) 237 | { 238 | uint target; 239 | int c; 240 | 241 | iunlock(ip); 242 | target = n; 243 | acquire(&cons.lock); 244 | while(n > 0){ 245 | while(input.r == input.w){ 246 | if(myproc()->killed){ 247 | release(&cons.lock); 248 | ilock(ip); 249 | return -1; 250 | } 251 | sleep(&input.r, &cons.lock); 252 | } 253 | c = input.buf[input.r++ % INPUT_BUF]; 254 | if(c == C('D')){ // EOF 255 | if(n < target){ 256 | // Save ^D for next time, to make sure 257 | // caller gets a 0-byte result. 258 | input.r--; 259 | } 260 | break; 261 | } 262 | *dst++ = c; 263 | --n; 264 | if(c == '\n') 265 | break; 266 | } 267 | release(&cons.lock); 268 | ilock(ip); 269 | 270 | return target - n; 271 | } 272 | 273 | int 274 | consolewrite(struct inode *ip, char *buf, int n) 275 | { 276 | int i; 277 | 278 | iunlock(ip); 279 | acquire(&cons.lock); 280 | for(i = 0; i < n; i++) 281 | consputc(buf[i] & 0xff); 282 | release(&cons.lock); 283 | ilock(ip); 284 | 285 | return n; 286 | } 287 | 288 | void 289 | consoleinit(void) 290 | { 291 | initlock(&cons.lock, "console"); 292 | 293 | devsw[CONSOLE].write = consolewrite; 294 | devsw[CONSOLE].read = consoleread; 295 | cons.locking = 1; 296 | 297 | ioapicenable(IRQ_KBD, 0); 298 | } 299 | 300 | -------------------------------------------------------------------------------- /code/gdbutil: -------------------------------------------------------------------------------- 1 | # -*- gdb-script -*- 2 | 3 | # Utility functions to pretty-print x86 segment/interrupt descriptors. 4 | # To load this file, run "source gdbutil" in gdb. 5 | # printdesc and printdescs are the main entry points. 6 | 7 | # IA32 2007, Volume 3A, Table 3-2 8 | set $STS_T16A = 0x1 9 | set $STS_LDT = 0x2 10 | set $STS_T16B = 0x3 11 | set $STS_CG16 = 0x4 12 | set $STS_TG = 0x5 13 | set $STS_IG16 = 0x6 14 | set $STS_TG16 = 0x7 15 | set $STS_T32A = 0x9 16 | set $STS_T32B = 0xB 17 | set $STS_CG32 = 0xC 18 | set $STS_IG32 = 0xE 19 | set $STS_TG32 = 0xF 20 | 21 | define outputsts 22 | while 1 23 | if $arg0 == $STS_T16A 24 | echo STS_T16A 25 | loop_break 26 | end 27 | if $arg0 == $STS_LDT 28 | echo STS_LDT\ 29 | loop_break 30 | end 31 | if $arg0 == $STS_T16B 32 | echo STS_T16B 33 | loop_break 34 | end 35 | if $arg0 == $STS_CG16 36 | echo STS_CG16 37 | loop_break 38 | end 39 | if $arg0 == $STS_TG 40 | echo STS_TG\ \ 41 | loop_break 42 | end 43 | if $arg0 == $STS_IG16 44 | echo STS_IG16 45 | loop_break 46 | end 47 | if $arg0 == $STS_TG16 48 | echo STS_TG16 49 | loop_break 50 | end 51 | if $arg0 == $STS_T32A 52 | echo STS_T32A 53 | loop_break 54 | end 55 | if $arg0 == $STS_T32B 56 | echo STS_T32B 57 | loop_break 58 | end 59 | if $arg0 == $STS_CG32 60 | echo STS_CG32 61 | loop_break 62 | end 63 | if $arg0 == $STS_IG32 64 | echo STS_IG32 65 | loop_break 66 | end 67 | if $arg0 == $STS_TG32 68 | echo STS_TG32 69 | loop_break 70 | end 71 | echo Reserved 72 | loop_break 73 | end 74 | end 75 | 76 | # IA32 2007, Volume 3A, Table 3-1 77 | set $STA_X = 0x8 78 | set $STA_E = 0x4 79 | set $STA_C = 0x4 80 | set $STA_W = 0x2 81 | set $STA_R = 0x2 82 | set $STA_A = 0x1 83 | 84 | define outputsta 85 | if $arg0 & $STA_X 86 | # Code segment 87 | echo code 88 | if $arg0 & $STA_C 89 | echo |STA_C 90 | end 91 | if $arg0 & $STA_R 92 | echo |STA_R 93 | end 94 | else 95 | # Data segment 96 | echo data 97 | if $arg0 & $STA_E 98 | echo |STA_E 99 | end 100 | if $arg0 & $STA_W 101 | echo |STA_W 102 | end 103 | end 104 | if $arg0 & $STA_A 105 | echo |STA_A 106 | else 107 | printf " " 108 | end 109 | end 110 | 111 | # xv6-specific 112 | set $SEG_KCODE = 1 113 | set $SEG_KDATA = 2 114 | set $SEG_KCPU = 3 115 | set $SEG_UCODE = 4 116 | set $SEG_UDATA = 5 117 | set $SEG_TSS = 6 118 | 119 | define outputcs 120 | if ($arg0 & 4) == 0 121 | if $arg0 >> 3 == $SEG_KCODE 122 | printf "SEG_KCODE<<3" 123 | end 124 | if $arg0 >> 3 == $SEG_KDATA 125 | printf "SEG_KDATA<<3" 126 | end 127 | if $arg0 >> 3 == $SEG_KCPU 128 | printf "SEG_KCPU<<3" 129 | end 130 | if $arg0 >> 3 == $SEG_UCODE 131 | printf "SEG_UCODE<<3" 132 | end 133 | if $arg0 >> 3 == $SEG_UDATA 134 | printf "SEG_UDATA<<3" 135 | end 136 | if $arg0 >> 3 == $SEG_TSS 137 | printf "SEG_TSS<<3" 138 | end 139 | if ($arg0 >> 3 < 1) + ($arg0 >> 3 > 6) 140 | printf "GDT[%d]", $arg0 >> 3 141 | end 142 | else 143 | printf "LDT[%d]", $arg0 >> 3 144 | end 145 | if ($arg0 & 3) > 0 146 | printf "|" 147 | outputdpl ($arg0&3) 148 | end 149 | end 150 | 151 | define outputdpl 152 | if $arg0 == 0 153 | printf "DPL_KERN" 154 | else 155 | if $arg0 == 3 156 | printf "DPL_USER" 157 | else 158 | printf "DPL%d", $arg0 159 | end 160 | end 161 | end 162 | 163 | define printdesc 164 | if $argc != 1 165 | echo Usage: printdesc expr 166 | else 167 | _printdesc ((uint*)&($arg0))[0] ((uint*)&($arg0))[1] 168 | printf "\n" 169 | end 170 | end 171 | 172 | document printdesc 173 | Print an x86 segment or gate descriptor. 174 | printdesc EXPR 175 | EXPR must evaluate to a descriptor value. It can be of any C type. 176 | end 177 | 178 | define _printdesc 179 | _printdesc1 $arg0 $arg1 ($arg1>>15&1) ($arg1>>13&3) ($arg1>>12&1) ($arg1>>8&15) 180 | end 181 | 182 | define _printdesc1 183 | # 2:P 3:DPL 4:S 5:Type 184 | if $arg2 == 0 185 | printf "P = 0 (Not present)" 186 | else 187 | printf "type = " 188 | if $arg4 == 0 189 | # System segment 190 | outputsts $arg5 191 | printf " (0x%x) ", $arg5 192 | _printsysdesc $arg0 $arg1 $arg5 193 | else 194 | # Code/data segment 195 | outputsta $arg5 196 | printf " " 197 | _printsegdesc $arg0 $arg1 198 | end 199 | 200 | printf " DPL = " 201 | outputdpl $arg3 202 | printf " (%d)", $arg3 203 | end 204 | end 205 | 206 | define _printsysdesc 207 | # 2:Type 208 | # GDB's || is buggy 209 | if ($arg2 == $STS_TG) + (($arg2&7) == $STS_IG16) + (($arg2&7) == $STS_TG16) 210 | # Gate descriptor 211 | _printgate $arg2 ($arg0>>16) ($arg0&0xFFFF) ($arg1>>16) 212 | else 213 | # System segment descriptor 214 | _printsegdesc $arg0 $arg1 215 | end 216 | end 217 | 218 | define _printgate 219 | # IA32 2007, Voume 3A, Figure 5-2 220 | # 0:Type 1:CS 2:Offset 15..0 3:Offset 31..16 221 | printf "CS = " 222 | outputcs $arg1 223 | printf " (%d)", $arg1 224 | 225 | if (($arg0&7) == $STS_IG16) + (($arg0&7) == $STS_TG16) 226 | printf " Offset = " 227 | output/a $arg3 << 16 | $arg2 228 | end 229 | end 230 | 231 | define _printsegdesc 232 | # IA32 20007, Volume 3A, Figure 3-8 and Figure 4-1 233 | _printsegdesc1 ($arg0>>16) ($arg1&0xFF) ($arg1>>24) ($arg0&0xFFFF) ($arg1>>16&15) ($arg1>>23&1) 234 | if ($arg1>>12&1) == 1 235 | printf " AVL = %d", $arg1>>20&1 236 | if ($arg1>>11&1) == 0 237 | # Data segment 238 | if ($arg1>>22&1) == 0 239 | printf " B = small (0) " 240 | else 241 | printf " B = big (1) " 242 | end 243 | else 244 | # Code segment 245 | printf " D = " 246 | if ($arg1>>22&1) == 0 247 | printf "16-bit (0)" 248 | else 249 | printf "32-bit (1)" 250 | end 251 | end 252 | end 253 | end 254 | 255 | define _printsegdesc1 256 | # 0:Base 0..15 1:Base 16..23 2:Base 24..32 3:Limit 0..15 4:Limit 16..19 5:G 257 | printf "base = 0x%08x", $arg0 | ($arg1<<16) | ($arg2<<24) 258 | printf " limit = 0x" 259 | if $arg5 == 0 260 | printf "%08x", $arg3 | ($arg4<<16) 261 | else 262 | printf "%08x", (($arg3 | ($arg4<<16)) << 12) | 0xFFF 263 | end 264 | end 265 | 266 | define printdescs 267 | if $argc < 1 || $argc > 2 268 | echo Usage: printdescs expr [count] 269 | else 270 | if $argc == 1 271 | _printdescs ($arg0) (sizeof($arg0)/sizeof(($arg0)[0])) 272 | else 273 | _printdescs ($arg0) ($arg1) 274 | end 275 | end 276 | end 277 | 278 | document printdescs 279 | Print an array of x86 segment or gate descriptors. 280 | printdescs EXPR [COUNT] 281 | EXPR must evaluate to an array of descriptors. 282 | end 283 | 284 | define _printdescs 285 | set $i = 0 286 | while $i < $arg1 287 | printf "[%d] ", $i 288 | printdesc $arg0[$i] 289 | set $i = $i + 1 290 | end 291 | end 292 | -------------------------------------------------------------------------------- /code/lapic.c: -------------------------------------------------------------------------------- 1 | // The local APIC manages internal (non-I/O) interrupts. 2 | // See Chapter 8 & Appendix C of Intel processor manual volume 3. 3 | 4 | #include "param.h" 5 | #include "types.h" 6 | #include "defs.h" 7 | #include "date.h" 8 | #include "memlayout.h" 9 | #include "traps.h" 10 | #include "mmu.h" 11 | #include "x86.h" 12 | 13 | // Local APIC registers, divided by 4 for use as uint[] indices. 14 | #define ID (0x0020/4) // ID 15 | #define VER (0x0030/4) // Version 16 | #define TPR (0x0080/4) // Task Priority 17 | #define EOI (0x00B0/4) // EOI 18 | #define SVR (0x00F0/4) // Spurious Interrupt Vector 19 | #define ENABLE 0x00000100 // Unit Enable 20 | #define ESR (0x0280/4) // Error Status 21 | #define ICRLO (0x0300/4) // Interrupt Command 22 | #define INIT 0x00000500 // INIT/RESET 23 | #define STARTUP 0x00000600 // Startup IPI 24 | #define DELIVS 0x00001000 // Delivery status 25 | #define ASSERT 0x00004000 // Assert interrupt (vs deassert) 26 | #define DEASSERT 0x00000000 27 | #define LEVEL 0x00008000 // Level triggered 28 | #define BCAST 0x00080000 // Send to all APICs, including self. 29 | #define BUSY 0x00001000 30 | #define FIXED 0x00000000 31 | #define ICRHI (0x0310/4) // Interrupt Command [63:32] 32 | #define TIMER (0x0320/4) // Local Vector Table 0 (TIMER) 33 | #define X1 0x0000000B // divide counts by 1 34 | #define PERIODIC 0x00020000 // Periodic 35 | #define PCINT (0x0340/4) // Performance Counter LVT 36 | #define LINT0 (0x0350/4) // Local Vector Table 1 (LINT0) 37 | #define LINT1 (0x0360/4) // Local Vector Table 2 (LINT1) 38 | #define ERROR (0x0370/4) // Local Vector Table 3 (ERROR) 39 | #define MASKED 0x00010000 // Interrupt masked 40 | #define TICR (0x0380/4) // Timer Initial Count 41 | #define TCCR (0x0390/4) // Timer Current Count 42 | #define TDCR (0x03E0/4) // Timer Divide Configuration 43 | 44 | volatile uint *lapic; // Initialized in mp.c 45 | 46 | //PAGEBREAK! 47 | static void 48 | lapicw(int index, int value) 49 | { 50 | lapic[index] = value; 51 | lapic[ID]; // wait for write to finish, by reading 52 | } 53 | 54 | void 55 | lapicinit(void) 56 | { 57 | if(!lapic) 58 | return; 59 | 60 | // Enable local APIC; set spurious interrupt vector. 61 | lapicw(SVR, ENABLE | (T_IRQ0 + IRQ_SPURIOUS)); 62 | 63 | // The timer repeatedly counts down at bus frequency 64 | // from lapic[TICR] and then issues an interrupt. 65 | // If xv6 cared more about precise timekeeping, 66 | // TICR would be calibrated using an external time source. 67 | lapicw(TDCR, X1); 68 | lapicw(TIMER, PERIODIC | (T_IRQ0 + IRQ_TIMER)); 69 | lapicw(TICR, 10000000); 70 | 71 | // Disable logical interrupt lines. 72 | lapicw(LINT0, MASKED); 73 | lapicw(LINT1, MASKED); 74 | 75 | // Disable performance counter overflow interrupts 76 | // on machines that provide that interrupt entry. 77 | if(((lapic[VER]>>16) & 0xFF) >= 4) 78 | lapicw(PCINT, MASKED); 79 | 80 | // Map error interrupt to IRQ_ERROR. 81 | lapicw(ERROR, T_IRQ0 + IRQ_ERROR); 82 | 83 | // Clear error status register (requires back-to-back writes). 84 | lapicw(ESR, 0); 85 | lapicw(ESR, 0); 86 | 87 | // Ack any outstanding interrupts. 88 | lapicw(EOI, 0); 89 | 90 | // Send an Init Level De-Assert to synchronise arbitration ID's. 91 | lapicw(ICRHI, 0); 92 | lapicw(ICRLO, BCAST | INIT | LEVEL); 93 | while(lapic[ICRLO] & DELIVS) 94 | ; 95 | 96 | // Enable interrupts on the APIC (but not on the processor). 97 | lapicw(TPR, 0); 98 | } 99 | 100 | int 101 | lapicid(void) 102 | { 103 | if (!lapic) 104 | return 0; 105 | return lapic[ID] >> 24; 106 | } 107 | 108 | // Acknowledge interrupt. 109 | void 110 | lapiceoi(void) 111 | { 112 | if(lapic) 113 | lapicw(EOI, 0); 114 | } 115 | 116 | // Spin for a given number of microseconds. 117 | // On real hardware would want to tune this dynamically. 118 | void 119 | microdelay(int us) 120 | { 121 | } 122 | 123 | #define CMOS_PORT 0x70 124 | #define CMOS_RETURN 0x71 125 | 126 | // Start additional processor running entry code at addr. 127 | // See Appendix B of MultiProcessor Specification. 128 | void 129 | lapicstartap(uchar apicid, uint addr) 130 | { 131 | int i; 132 | ushort *wrv; 133 | 134 | // "The BSP must initialize CMOS shutdown code to 0AH 135 | // and the warm reset vector (DWORD based at 40:67) to point at 136 | // the AP startup code prior to the [universal startup algorithm]." 137 | outb(CMOS_PORT, 0xF); // offset 0xF is shutdown code 138 | outb(CMOS_PORT+1, 0x0A); 139 | wrv = (ushort*)P2V((0x40<<4 | 0x67)); // Warm reset vector 140 | wrv[0] = 0; 141 | wrv[1] = addr >> 4; 142 | 143 | // "Universal startup algorithm." 144 | // Send INIT (level-triggered) interrupt to reset other CPU. 145 | lapicw(ICRHI, apicid<<24); 146 | lapicw(ICRLO, INIT | LEVEL | ASSERT); 147 | microdelay(200); 148 | lapicw(ICRLO, INIT | LEVEL); 149 | microdelay(100); // should be 10ms, but too slow in Bochs! 150 | 151 | // Send startup IPI (twice!) to enter code. 152 | // Regular hardware is supposed to only accept a STARTUP 153 | // when it is in the halted state due to an INIT. So the second 154 | // should be ignored, but it is part of the official Intel algorithm. 155 | // Bochs complains about the second one. Too bad for Bochs. 156 | for(i = 0; i < 2; i++){ 157 | lapicw(ICRHI, apicid<<24); 158 | lapicw(ICRLO, STARTUP | (addr>>12)); 159 | microdelay(200); 160 | } 161 | } 162 | 163 | #define CMOS_STATA 0x0a 164 | #define CMOS_STATB 0x0b 165 | #define CMOS_UIP (1 << 7) // RTC update in progress 166 | 167 | #define SECS 0x00 168 | #define MINS 0x02 169 | #define HOURS 0x04 170 | #define DAY 0x07 171 | #define MONTH 0x08 172 | #define YEAR 0x09 173 | 174 | static uint cmos_read(uint reg) 175 | { 176 | outb(CMOS_PORT, reg); 177 | microdelay(200); 178 | 179 | return inb(CMOS_RETURN); 180 | } 181 | 182 | static void fill_rtcdate(struct rtcdate *r) 183 | { 184 | r->second = cmos_read(SECS); 185 | r->minute = cmos_read(MINS); 186 | r->hour = cmos_read(HOURS); 187 | r->day = cmos_read(DAY); 188 | r->month = cmos_read(MONTH); 189 | r->year = cmos_read(YEAR); 190 | } 191 | 192 | // qemu seems to use 24-hour GWT and the values are BCD encoded 193 | void cmostime(struct rtcdate *r) 194 | { 195 | struct rtcdate t1, t2; 196 | int sb, bcd; 197 | 198 | sb = cmos_read(CMOS_STATB); 199 | 200 | bcd = (sb & (1 << 2)) == 0; 201 | 202 | // make sure CMOS doesn't modify time while we read it 203 | for(;;) { 204 | fill_rtcdate(&t1); 205 | if(cmos_read(CMOS_STATA) & CMOS_UIP) 206 | continue; 207 | fill_rtcdate(&t2); 208 | if(memcmp(&t1, &t2, sizeof(t1)) == 0) 209 | break; 210 | } 211 | 212 | // convert 213 | if(bcd) { 214 | #define CONV(x) (t1.x = ((t1.x >> 4) * 10) + (t1.x & 0xf)) 215 | CONV(second); 216 | CONV(minute); 217 | CONV(hour ); 218 | CONV(day ); 219 | CONV(month ); 220 | CONV(year ); 221 | #undef CONV 222 | } 223 | 224 | *r = t1; 225 | r->year += 2000; 226 | } 227 | -------------------------------------------------------------------------------- /code/mkfs.c: -------------------------------------------------------------------------------- 1 | #include 2 | #include 3 | #include 4 | #include 5 | #include 6 | #include 7 | 8 | #define stat xv6_stat // avoid clash with host struct stat 9 | #include "types.h" 10 | #include "fs.h" 11 | #include "stat.h" 12 | #include "param.h" 13 | 14 | #ifndef static_assert 15 | #define static_assert(a, b) do { switch (0) case 0: case (a): ; } while (0) 16 | #endif 17 | 18 | #define NINODES 200 19 | 20 | // Disk layout: 21 | // [ boot block | sb block | log | inode blocks | free bit map | data blocks ] 22 | 23 | int nbitmap = FSSIZE/(BSIZE*8) + 1; 24 | int ninodeblocks = NINODES / IPB + 1; 25 | int nlog = LOGSIZE; 26 | int nmeta; // Number of meta blocks (boot, sb, nlog, inode, bitmap) 27 | int nblocks; // Number of data blocks 28 | 29 | int fsfd; 30 | struct superblock sb; 31 | char zeroes[BSIZE]; 32 | uint freeinode = 1; 33 | uint freeblock; 34 | 35 | 36 | void balloc(int); 37 | void wsect(uint, void*); 38 | void winode(uint, struct dinode*); 39 | void rinode(uint inum, struct dinode *ip); 40 | void rsect(uint sec, void *buf); 41 | uint ialloc(ushort type); 42 | void iappend(uint inum, void *p, int n); 43 | 44 | // convert to intel byte order 45 | ushort 46 | xshort(ushort x) 47 | { 48 | ushort y; 49 | uchar *a = (uchar*)&y; 50 | a[0] = x; 51 | a[1] = x >> 8; 52 | return y; 53 | } 54 | 55 | uint 56 | xint(uint x) 57 | { 58 | uint y; 59 | uchar *a = (uchar*)&y; 60 | a[0] = x; 61 | a[1] = x >> 8; 62 | a[2] = x >> 16; 63 | a[3] = x >> 24; 64 | return y; 65 | } 66 | 67 | int 68 | main(int argc, char *argv[]) 69 | { 70 | int i, cc, fd; 71 | uint rootino, inum, off; 72 | struct dirent de; 73 | char buf[BSIZE]; 74 | struct dinode din; 75 | 76 | 77 | static_assert(sizeof(int) == 4, "Integers must be 4 bytes!"); 78 | 79 | if(argc < 2){ 80 | fprintf(stderr, "Usage: mkfs fs.img files...\n"); 81 | exit(1); 82 | } 83 | 84 | assert((BSIZE % sizeof(struct dinode)) == 0); 85 | assert((BSIZE % sizeof(struct dirent)) == 0); 86 | 87 | fsfd = open(argv[1], O_RDWR|O_CREAT|O_TRUNC, 0666); 88 | if(fsfd < 0){ 89 | perror(argv[1]); 90 | exit(1); 91 | } 92 | 93 | // 1 fs block = 1 disk sector 94 | nmeta = 2 + nlog + ninodeblocks + nbitmap; 95 | nblocks = FSSIZE - nmeta; 96 | 97 | sb.size = xint(FSSIZE); 98 | sb.nblocks = xint(nblocks); 99 | sb.ninodes = xint(NINODES); 100 | sb.nlog = xint(nlog); 101 | sb.logstart = xint(2); 102 | sb.inodestart = xint(2+nlog); 103 | sb.bmapstart = xint(2+nlog+ninodeblocks); 104 | 105 | printf("nmeta %d (boot, super, log blocks %u inode blocks %u, bitmap blocks %u) blocks %d total %d\n", 106 | nmeta, nlog, ninodeblocks, nbitmap, nblocks, FSSIZE); 107 | 108 | freeblock = nmeta; // the first free block that we can allocate 109 | 110 | for(i = 0; i < FSSIZE; i++) 111 | wsect(i, zeroes); 112 | 113 | memset(buf, 0, sizeof(buf)); 114 | memmove(buf, &sb, sizeof(sb)); 115 | wsect(1, buf); 116 | 117 | rootino = ialloc(T_DIR); 118 | assert(rootino == ROOTINO); 119 | 120 | bzero(&de, sizeof(de)); 121 | de.inum = xshort(rootino); 122 | strcpy(de.name, "."); 123 | iappend(rootino, &de, sizeof(de)); 124 | 125 | bzero(&de, sizeof(de)); 126 | de.inum = xshort(rootino); 127 | strcpy(de.name, ".."); 128 | iappend(rootino, &de, sizeof(de)); 129 | 130 | for(i = 2; i < argc; i++){ 131 | assert(index(argv[i], '/') == 0); 132 | 133 | if((fd = open(argv[i], 0)) < 0){ 134 | perror(argv[i]); 135 | exit(1); 136 | } 137 | 138 | // Skip leading _ in name when writing to file system. 139 | // The binaries are named _rm, _cat, etc. to keep the 140 | // build operating system from trying to execute them 141 | // in place of system binaries like rm and cat. 142 | if(argv[i][0] == '_') 143 | ++argv[i]; 144 | 145 | inum = ialloc(T_FILE); 146 | 147 | bzero(&de, sizeof(de)); 148 | de.inum = xshort(inum); 149 | strncpy(de.name, argv[i], DIRSIZ); 150 | iappend(rootino, &de, sizeof(de)); 151 | 152 | while((cc = read(fd, buf, sizeof(buf))) > 0) 153 | iappend(inum, buf, cc); 154 | 155 | close(fd); 156 | } 157 | 158 | // fix size of root inode dir 159 | rinode(rootino, &din); 160 | off = xint(din.size); 161 | off = ((off/BSIZE) + 1) * BSIZE; 162 | din.size = xint(off); 163 | winode(rootino, &din); 164 | 165 | balloc(freeblock); 166 | 167 | exit(0); 168 | } 169 | 170 | void 171 | wsect(uint sec, void *buf) 172 | { 173 | if(lseek(fsfd, sec * BSIZE, 0) != sec * BSIZE){ 174 | perror("lseek"); 175 | exit(1); 176 | } 177 | if(write(fsfd, buf, BSIZE) != BSIZE){ 178 | perror("write"); 179 | exit(1); 180 | } 181 | } 182 | 183 | void 184 | winode(uint inum, struct dinode *ip) 185 | { 186 | char buf[BSIZE]; 187 | uint bn; 188 | struct dinode *dip; 189 | 190 | bn = IBLOCK(inum, sb); 191 | rsect(bn, buf); 192 | dip = ((struct dinode*)buf) + (inum % IPB); 193 | *dip = *ip; 194 | wsect(bn, buf); 195 | } 196 | 197 | void 198 | rinode(uint inum, struct dinode *ip) 199 | { 200 | char buf[BSIZE]; 201 | uint bn; 202 | struct dinode *dip; 203 | 204 | bn = IBLOCK(inum, sb); 205 | rsect(bn, buf); 206 | dip = ((struct dinode*)buf) + (inum % IPB); 207 | *ip = *dip; 208 | } 209 | 210 | void 211 | rsect(uint sec, void *buf) 212 | { 213 | if(lseek(fsfd, sec * BSIZE, 0) != sec * BSIZE){ 214 | perror("lseek"); 215 | exit(1); 216 | } 217 | if(read(fsfd, buf, BSIZE) != BSIZE){ 218 | perror("read"); 219 | exit(1); 220 | } 221 | } 222 | 223 | uint 224 | ialloc(ushort type) 225 | { 226 | uint inum = freeinode++; 227 | struct dinode din; 228 | 229 | bzero(&din, sizeof(din)); 230 | din.type = xshort(type); 231 | din.nlink = xshort(1); 232 | din.size = xint(0); 233 | winode(inum, &din); 234 | return inum; 235 | } 236 | 237 | void 238 | balloc(int used) 239 | { 240 | uchar buf[BSIZE]; 241 | int i; 242 | 243 | printf("balloc: first %d blocks have been allocated\n", used); 244 | assert(used < BSIZE*8); 245 | bzero(buf, BSIZE); 246 | for(i = 0; i < used; i++){ 247 | buf[i/8] = buf[i/8] | (0x1 << (i%8)); 248 | } 249 | printf("balloc: write bitmap block at sector %d\n", sb.bmapstart); 250 | wsect(sb.bmapstart, buf); 251 | } 252 | 253 | #define min(a, b) ((a) < (b) ? (a) : (b)) 254 | 255 | void 256 | iappend(uint inum, void *xp, int n) 257 | { 258 | char *p = (char*)xp; 259 | uint fbn, off, n1; 260 | struct dinode din; 261 | char buf[BSIZE]; 262 | uint indirect[NINDIRECT]; 263 | uint x; 264 | 265 | rinode(inum, &din); 266 | off = xint(din.size); 267 | // printf("append inum %d at off %d sz %d\n", inum, off, n); 268 | while(n > 0){ 269 | fbn = off / BSIZE; 270 | assert(fbn < MAXFILE); 271 | if(fbn < NDIRECT){ 272 | if(xint(din.addrs[fbn]) == 0){ 273 | din.addrs[fbn] = xint(freeblock++); 274 | } 275 | x = xint(din.addrs[fbn]); 276 | } else { 277 | if(xint(din.addrs[NDIRECT]) == 0){ 278 | din.addrs[NDIRECT] = xint(freeblock++); 279 | } 280 | rsect(xint(din.addrs[NDIRECT]), (char*)indirect); 281 | if(indirect[fbn - NDIRECT] == 0){ 282 | indirect[fbn - NDIRECT] = xint(freeblock++); 283 | wsect(xint(din.addrs[NDIRECT]), (char*)indirect); 284 | } 285 | x = xint(indirect[fbn-NDIRECT]); 286 | } 287 | n1 = min(n, (fbn + 1) * BSIZE - off); 288 | rsect(x, buf); 289 | bcopy(p, buf + off - (fbn * BSIZE), n1); 290 | wsect(x, buf); 291 | n -= n1; 292 | off += n1; 293 | p += n1; 294 | } 295 | din.size = xint(off); 296 | winode(inum, &din); 297 | } 298 | -------------------------------------------------------------------------------- /code/Makefile: -------------------------------------------------------------------------------- 1 | OBJS = \ 2 | bio.o\ 3 | console.o\ 4 | exec.o\ 5 | file.o\ 6 | fs.o\ 7 | ide.o\ 8 | ioapic.o\ 9 | kalloc.o\ 10 | kbd.o\ 11 | lapic.o\ 12 | log.o\ 13 | main.o\ 14 | mp.o\ 15 | picirq.o\ 16 | pipe.o\ 17 | proc.o\ 18 | sleeplock.o\ 19 | spinlock.o\ 20 | string.o\ 21 | swtch.o\ 22 | syscall.o\ 23 | sysfile.o\ 24 | sysproc.o\ 25 | trapasm.o\ 26 | trap.o\ 27 | uart.o\ 28 | vectors.o\ 29 | vm.o\ 30 | 31 | # Cross-compiling (e.g., on Mac OS X) 32 | # TOOLPREFIX = i386-jos-elf 33 | 34 | # Using native tools (e.g., on X86 Linux) 35 | #TOOLPREFIX = 36 | 37 | # Try to infer the correct TOOLPREFIX if not set 38 | ifndef TOOLPREFIX 39 | TOOLPREFIX := $(shell if i386-jos-elf-objdump -i 2>&1 | grep '^elf32-i386$$' >/dev/null 2>&1; \ 40 | then echo 'i386-jos-elf-'; \ 41 | elif objdump -i 2>&1 | grep 'elf32-i386' >/dev/null 2>&1; \ 42 | then echo ''; \ 43 | else echo "***" 1>&2; \ 44 | echo "*** Error: Couldn't find an i386-*-elf version of GCC/binutils." 1>&2; \ 45 | echo "*** Is the directory with i386-jos-elf-gcc in your PATH?" 1>&2; \ 46 | echo "*** If your i386-*-elf toolchain is installed with a command" 1>&2; \ 47 | echo "*** prefix other than 'i386-jos-elf-', set your TOOLPREFIX" 1>&2; \ 48 | echo "*** environment variable to that prefix and run 'make' again." 1>&2; \ 49 | echo "*** To turn off this error, run 'gmake TOOLPREFIX= ...'." 1>&2; \ 50 | echo "***" 1>&2; exit 1; fi) 51 | endif 52 | 53 | # If the makefile can't find QEMU, specify its path here 54 | # QEMU = qemu-system-i386 55 | 56 | # Try to infer the correct QEMU 57 | ifndef QEMU 58 | QEMU = /home/kexinxin/qemu/bin/qemu-system-x86_64 59 | endif 60 | 61 | CC = $(TOOLPREFIX)gcc 62 | AS = $(TOOLPREFIX)gas 63 | LD = $(TOOLPREFIX)ld 64 | OBJCOPY = $(TOOLPREFIX)objcopy 65 | OBJDUMP = $(TOOLPREFIX)objdump 66 | CFLAGS = -fno-pic -static -fno-builtin -fno-strict-aliasing -O2 -Wall -MD -ggdb -m32 -Werror -fno-omit-frame-pointer 67 | #CFLAGS = -fno-pic -static -fno-builtin -fno-strict-aliasing -fvar-tracking -fvar-tracking-assignments -O0 -g -Wall -MD -gdwarf-2 -m32 -Werror -fno-omit-frame-pointer 68 | CFLAGS += $(shell $(CC) -fno-stack-protector -E -x c /dev/null >/dev/null 2>&1 && echo -fno-stack-protector) 69 | ASFLAGS = -m32 -gdwarf-2 -Wa,-divide 70 | # FreeBSD ld wants ``elf_i386_fbsd'' 71 | LDFLAGS += -m $(shell $(LD) -V | grep elf_i386 2>/dev/null | head -n 1) 72 | 73 | xv6.img: bootblock kernel fs.img 74 | dd if=/dev/zero of=xv6.img count=10000 75 | dd if=bootblock of=xv6.img conv=notrunc 76 | dd if=kernel of=xv6.img seek=1 conv=notrunc 77 | 78 | xv6memfs.img: bootblock kernelmemfs 79 | dd if=/dev/zero of=xv6memfs.img count=10000 80 | dd if=bootblock of=xv6memfs.img conv=notrunc 81 | dd if=kernelmemfs of=xv6memfs.img seek=1 conv=notrunc 82 | 83 | bootblock: bootasm.S bootmain.c 84 | $(CC) $(CFLAGS) -fno-pic -O -nostdinc -I. -c bootmain.c 85 | $(CC) $(CFLAGS) -fno-pic -nostdinc -I. -c bootasm.S 86 | $(LD) $(LDFLAGS) -N -e start -Ttext 0x7C00 -o bootblock.o bootasm.o bootmain.o 87 | $(OBJDUMP) -S bootblock.o > bootblock.asm 88 | $(OBJCOPY) -S -O binary -j .text bootblock.o bootblock 89 | ./sign.pl bootblock 90 | 91 | entryother: entryother.S 92 | $(CC) $(CFLAGS) -fno-pic -nostdinc -I. -c entryother.S 93 | $(LD) $(LDFLAGS) -N -e start -Ttext 0x7000 -o bootblockother.o entryother.o 94 | $(OBJCOPY) -S -O binary -j .text bootblockother.o entryother 95 | $(OBJDUMP) -S bootblockother.o > entryother.asm 96 | 97 | initcode: initcode.S 98 | $(CC) $(CFLAGS) -nostdinc -I. -c initcode.S 99 | $(LD) $(LDFLAGS) -N -e start -Ttext 0 -o initcode.out initcode.o 100 | $(OBJCOPY) -S -O binary initcode.out initcode 101 | $(OBJDUMP) -S initcode.o > initcode.asm 102 | 103 | kernel: $(OBJS) entry.o entryother initcode kernel.ld 104 | $(LD) $(LDFLAGS) -T kernel.ld -o kernel entry.o $(OBJS) -b binary initcode entryother 105 | $(OBJDUMP) -S kernel > kernel.asm 106 | $(OBJDUMP) -t kernel | sed '1,/SYMBOL TABLE/d; s/ .* / /; /^$$/d' > kernel.sym 107 | 108 | # kernelmemfs is a copy of kernel that maintains the 109 | # disk image in memory instead of writing to a disk. 110 | # This is not so useful for testing persistent storage or 111 | # exploring disk buffering implementations, but it is 112 | # great for testing the kernel on real hardware without 113 | # needing a scratch disk. 114 | MEMFSOBJS = $(filter-out ide.o,$(OBJS)) memide.o 115 | kernelmemfs: $(MEMFSOBJS) entry.o entryother initcode kernel.ld fs.img 116 | $(LD) $(LDFLAGS) -T kernel.ld -o kernelmemfs entry.o $(MEMFSOBJS) -b binary initcode entryother fs.img 117 | $(OBJDUMP) -S kernelmemfs > kernelmemfs.asm 118 | $(OBJDUMP) -t kernelmemfs | sed '1,/SYMBOL TABLE/d; s/ .* / /; /^$$/d' > kernelmemfs.sym 119 | 120 | tags: $(OBJS) entryother.S _init 121 | etags *.S *.c 122 | 123 | vectors.S: vectors.pl 124 | perl vectors.pl > vectors.S 125 | 126 | ULIB = ulib.o usys.o printf.o umalloc.o 127 | 128 | _%: %.o $(ULIB) 129 | $(LD) $(LDFLAGS) -N -e main -Ttext 0 -o $@ $^ 130 | $(OBJDUMP) -S $@ > $*.asm 131 | $(OBJDUMP) -t $@ | sed '1,/SYMBOL TABLE/d; s/ .* / /; /^$$/d' > $*.sym 132 | 133 | _forktest: forktest.o $(ULIB) 134 | # forktest has less library code linked in - needs to be small 135 | # in order to be able to max out the proc table. 136 | $(LD) $(LDFLAGS) -N -e main -Ttext 0 -o _forktest forktest.o ulib.o usys.o 137 | $(OBJDUMP) -S _forktest > forktest.asm 138 | _uthread: uthread.o uthread_switch.o 139 | $(LD) $(LDFLAGS) -N -e main -Ttext 0 -o _uthread uthread.o uthread_switch.o $(ULIB) 140 | $(OBJDUMP) -S _uthread > uthread.asm 141 | 142 | 143 | mkfs: mkfs.c fs.h 144 | gcc -Werror -Wall -o mkfs mkfs.c 145 | 146 | # Prevent deletion of intermediate files, e.g. cat.o, after first build, so 147 | # that disk image changes after first build are persistent until clean. More 148 | # details: 149 | # http://www.gnu.org/software/make/manual/html_node/Chained-Rules.html 150 | .PRECIOUS: %.o 151 | 152 | UPROGS=\ 153 | _cat\ 154 | _echo\ 155 | _forktest\ 156 | _grep\ 157 | _init\ 158 | _kill\ 159 | _ln\ 160 | _ls\ 161 | _mkdir\ 162 | _rm\ 163 | _sh\ 164 | _stressfs\ 165 | _usertests\ 166 | _wc\ 167 | _zombie\ 168 | _date\ 169 | _alarmtest\ 170 | _uthread\ 171 | _big\ 172 | 173 | fs.img: mkfs README $(UPROGS) 174 | ./mkfs fs.img README $(UPROGS) 175 | 176 | -include *.d 177 | 178 | clean: 179 | rm -f *.tex *.dvi *.idx *.aux *.log *.ind *.ilg \ 180 | *.o *.d *.asm *.sym vectors.S bootblock entryother \ 181 | initcode initcode.out kernel xv6.img fs.img kernelmemfs mkfs \ 182 | .gdbinit \ 183 | $(UPROGS) 184 | 185 | # make a printout 186 | FILES = $(shell grep -v '^\#' runoff.list) 187 | PRINT = runoff.list runoff.spec README toc.hdr toc.ftr $(FILES) 188 | 189 | xv6.pdf: $(PRINT) 190 | ./runoff 191 | ls -l xv6.pdf 192 | 193 | print: xv6.pdf 194 | 195 | # run in emulators 196 | 197 | bochs : fs.img xv6.img 198 | if [ ! -e .bochsrc ]; then ln -s dot-bochsrc .bochsrc; fi 199 | bochs -q 200 | 201 | # try to generate a unique GDB port 202 | GDBPORT = $(shell expr `id -u` % 5000 + 25000) 203 | # QEMU's gdb stub command line changed in 0.11 204 | QEMUGDB = $(shell if $(QEMU) -help | grep -q '^-gdb'; \ 205 | then echo "-gdb tcp::$(GDBPORT)"; \ 206 | else echo "-s -p $(GDBPORT)"; fi) 207 | ifndef CPUS 208 | CPUS := 1 209 | endif 210 | QEMUEXTRA = -snapshot 211 | QEMUOPTS = -drive file=fs.img,index=1,media=disk,format=raw -drive file=xv6.img,index=0,media=disk,format=raw -smp $(CPUS) -m 512 $(QEMUEXTRA) 212 | 213 | qemu: fs.img xv6.img 214 | $(QEMU) -serial mon:stdio $(QEMUOPTS) 215 | 216 | qemu-memfs: xv6memfs.img 217 | $(QEMU) -drive file=xv6memfs.img,index=0,media=disk,format=raw -smp $(CPUS) -m 256 218 | 219 | qemu-nox: fs.img xv6.img 220 | $(QEMU) -nographic $(QEMUOPTS) 221 | 222 | .gdbinit: .gdbinit.tmpl 223 | sed "s/localhost:1234/localhost:$(GDBPORT)/" < $^ > $@ 224 | 225 | qemu-gdb: fs.img xv6.img .gdbinit 226 | @echo "*** Now run 'gdb'." 1>&2 227 | $(QEMU) -serial mon:stdio $(QEMUOPTS) -S $(QEMUGDB) 228 | 229 | qemu-nox-gdb: fs.img xv6.img .gdbinit 230 | @echo "*** Now run 'gdb'." 1>&2 231 | $(QEMU) -nographic $(QEMUOPTS) -S $(QEMUGDB) 232 | 233 | # CUT HERE 234 | # prepare dist for students 235 | # after running make dist, probably want to 236 | # rename it to rev0 or rev1 or so on and then 237 | # check in that version. 238 | 239 | EXTRA=\ 240 | mkfs.c ulib.c user.h cat.c echo.c forktest.c grep.c kill.c\ 241 | ln.c ls.c mkdir.c rm.c stressfs.c usertests.c wc.c zombie.c\ 242 | printf.c umalloc.c\ 243 | README dot-bochsrc *.pl toc.* runoff runoff1 runoff.list\ 244 | .gdbinit.tmpl gdbutil\ 245 | 246 | dist: 247 | rm -rf dist 248 | mkdir dist 249 | for i in $(FILES); \ 250 | do \ 251 | grep -v PAGEBREAK $$i >dist/$$i; \ 252 | done 253 | sed '/CUT HERE/,$$d' Makefile >dist/Makefile 254 | echo >dist/runoff.spec 255 | cp $(EXTRA) dist 256 | 257 | dist-test: 258 | rm -rf dist 259 | make dist 260 | rm -rf dist-test 261 | mkdir dist-test 262 | cp dist/* dist-test 263 | cd dist-test; $(MAKE) print 264 | cd dist-test; $(MAKE) bochs || true 265 | cd dist-test; $(MAKE) qemu 266 | 267 | # update this rule (change rev#) when it is time to 268 | # make a new revision. 269 | tar: 270 | rm -rf /tmp/xv6 271 | mkdir -p /tmp/xv6 272 | cp dist/* dist/.gdbinit.tmpl /tmp/xv6 273 | (cd /tmp; tar cf - xv6) | gzip >xv6-rev10.tar.gz # the next one will be 10 (9/17) 274 | 275 | .PHONY: dist-test dist 276 | -------------------------------------------------------------------------------- /code/sysfile.c: -------------------------------------------------------------------------------- 1 | // 2 | // File-system system calls. 3 | // Mostly argument checking, since we don't trust 4 | // user code, and calls into file.c and fs.c. 5 | // 6 | 7 | #include "types.h" 8 | #include "defs.h" 9 | #include "param.h" 10 | #include "stat.h" 11 | #include "mmu.h" 12 | #include "proc.h" 13 | #include "fs.h" 14 | #include "spinlock.h" 15 | #include "sleeplock.h" 16 | #include "file.h" 17 | #include "fcntl.h" 18 | 19 | // Fetch the nth word-sized system call argument as a file descriptor 20 | // and return both the descriptor and the corresponding struct file. 21 | static int 22 | argfd(int n, int *pfd, struct file **pf) 23 | { 24 | int fd; 25 | struct file *f; 26 | 27 | if(argint(n, &fd) < 0) 28 | return -1; 29 | if(fd < 0 || fd >= NOFILE || (f=myproc()->ofile[fd]) == 0) 30 | return -1; 31 | if(pfd) 32 | *pfd = fd; 33 | if(pf) 34 | *pf = f; 35 | return 0; 36 | } 37 | 38 | // Allocate a file descriptor for the given file. 39 | // Takes over file reference from caller on success. 40 | static int 41 | fdalloc(struct file *f) 42 | { 43 | int fd; 44 | struct proc *curproc = myproc(); 45 | 46 | for(fd = 0; fd < NOFILE; fd++){ 47 | if(curproc->ofile[fd] == 0){ 48 | curproc->ofile[fd] = f; 49 | return fd; 50 | } 51 | } 52 | return -1; 53 | } 54 | 55 | int 56 | sys_dup(void) 57 | { 58 | struct file *f; 59 | int fd; 60 | 61 | if(argfd(0, 0, &f) < 0) 62 | return -1; 63 | if((fd=fdalloc(f)) < 0) 64 | return -1; 65 | filedup(f); 66 | return fd; 67 | } 68 | 69 | int 70 | sys_read(void) 71 | { 72 | struct file *f; 73 | int n; 74 | char *p; 75 | 76 | if(argfd(0, 0, &f) < 0 || argint(2, &n) < 0 || argptr(1, &p, n) < 0) 77 | return -1; 78 | return fileread(f, p, n); 79 | } 80 | 81 | int 82 | sys_write(void) 83 | { 84 | struct file *f; 85 | int n; 86 | char *p; 87 | 88 | if(argfd(0, 0, &f) < 0 || argint(2, &n) < 0 || argptr(1, &p, n) < 0) 89 | return -1; 90 | return filewrite(f, p, n); 91 | } 92 | 93 | int 94 | sys_close(void) 95 | { 96 | int fd; 97 | struct file *f; 98 | 99 | if(argfd(0, &fd, &f) < 0) 100 | return -1; 101 | myproc()->ofile[fd] = 0; 102 | fileclose(f); 103 | return 0; 104 | } 105 | 106 | int 107 | sys_fstat(void) 108 | { 109 | struct file *f; 110 | struct stat *st; 111 | 112 | if(argfd(0, 0, &f) < 0 || argptr(1, (void*)&st, sizeof(*st)) < 0) 113 | return -1; 114 | return filestat(f, st); 115 | } 116 | 117 | // Create the path new as a link to the same inode as old. 118 | int 119 | sys_link(void) 120 | { 121 | char name[DIRSIZ], *new, *old; 122 | struct inode *dp, *ip; 123 | 124 | if(argstr(0, &old) < 0 || argstr(1, &new) < 0) 125 | return -1; 126 | 127 | begin_op(); 128 | if((ip = namei(old)) == 0){ 129 | end_op(); 130 | return -1; 131 | } 132 | 133 | ilock(ip); 134 | if(ip->type == T_DIR){ 135 | iunlockput(ip); 136 | end_op(); 137 | return -1; 138 | } 139 | 140 | ip->nlink++; 141 | iupdate(ip); 142 | iunlock(ip); 143 | 144 | if((dp = nameiparent(new, name)) == 0) 145 | goto bad; 146 | ilock(dp); 147 | if(dp->dev != ip->dev || dirlink(dp, name, ip->inum) < 0){ 148 | iunlockput(dp); 149 | goto bad; 150 | } 151 | iunlockput(dp); 152 | iput(ip); 153 | 154 | end_op(); 155 | 156 | return 0; 157 | 158 | bad: 159 | ilock(ip); 160 | ip->nlink--; 161 | iupdate(ip); 162 | iunlockput(ip); 163 | end_op(); 164 | return -1; 165 | } 166 | 167 | // Is the directory dp empty except for "." and ".." ? 168 | static int 169 | isdirempty(struct inode *dp) 170 | { 171 | int off; 172 | struct dirent de; 173 | 174 | for(off=2*sizeof(de); offsize; off+=sizeof(de)){ 175 | if(readi(dp, (char*)&de, off, sizeof(de)) != sizeof(de)) 176 | panic("isdirempty: readi"); 177 | if(de.inum != 0) 178 | return 0; 179 | } 180 | return 1; 181 | } 182 | 183 | //PAGEBREAK! 184 | int 185 | sys_unlink(void) 186 | { 187 | struct inode *ip, *dp; 188 | struct dirent de; 189 | char name[DIRSIZ], *path; 190 | uint off; 191 | 192 | if(argstr(0, &path) < 0) 193 | return -1; 194 | 195 | begin_op(); 196 | if((dp = nameiparent(path, name)) == 0){ 197 | end_op(); 198 | return -1; 199 | } 200 | 201 | ilock(dp); 202 | 203 | // Cannot unlink "." or "..". 204 | if(namecmp(name, ".") == 0 || namecmp(name, "..") == 0) 205 | goto bad; 206 | 207 | if((ip = dirlookup(dp, name, &off)) == 0) 208 | goto bad; 209 | ilock(ip); 210 | 211 | if(ip->nlink < 1) 212 | panic("unlink: nlink < 1"); 213 | if(ip->type == T_DIR && !isdirempty(ip)){ 214 | iunlockput(ip); 215 | goto bad; 216 | } 217 | 218 | memset(&de, 0, sizeof(de)); 219 | if(writei(dp, (char*)&de, off, sizeof(de)) != sizeof(de)) 220 | panic("unlink: writei"); 221 | if(ip->type == T_DIR){ 222 | dp->nlink--; 223 | iupdate(dp); 224 | } 225 | iunlockput(dp); 226 | 227 | ip->nlink--; 228 | iupdate(ip); 229 | iunlockput(ip); 230 | 231 | end_op(); 232 | 233 | return 0; 234 | 235 | bad: 236 | iunlockput(dp); 237 | end_op(); 238 | return -1; 239 | } 240 | 241 | static struct inode* 242 | create(char *path, short type, short major, short minor) 243 | { 244 | uint off; 245 | struct inode *ip, *dp; 246 | char name[DIRSIZ]; 247 | 248 | if((dp = nameiparent(path, name)) == 0) 249 | return 0; 250 | ilock(dp); 251 | 252 | if((ip = dirlookup(dp, name, &off)) != 0){ 253 | iunlockput(dp); 254 | ilock(ip); 255 | if(type == T_FILE && ip->type == T_FILE) 256 | return ip; 257 | iunlockput(ip); 258 | return 0; 259 | } 260 | 261 | if((ip = ialloc(dp->dev, type)) == 0) 262 | panic("create: ialloc"); 263 | 264 | ilock(ip); 265 | ip->major = major; 266 | ip->minor = minor; 267 | ip->nlink = 1; 268 | iupdate(ip); 269 | 270 | if(type == T_DIR){ // Create . and .. entries. 271 | dp->nlink++; // for ".." 272 | iupdate(dp); 273 | // No ip->nlink++ for ".": avoid cyclic ref count. 274 | if(dirlink(ip, ".", ip->inum) < 0 || dirlink(ip, "..", dp->inum) < 0) 275 | panic("create dots"); 276 | } 277 | 278 | if(dirlink(dp, name, ip->inum) < 0) 279 | panic("create: dirlink"); 280 | 281 | iunlockput(dp); 282 | 283 | return ip; 284 | } 285 | 286 | int 287 | sys_open(void) 288 | { 289 | char *path; 290 | int fd, omode; 291 | struct file *f; 292 | struct inode *ip; 293 | 294 | if(argstr(0, &path) < 0 || argint(1, &omode) < 0) 295 | return -1; 296 | 297 | begin_op(); 298 | 299 | if(omode & O_CREATE){ 300 | ip = create(path, T_FILE, 0, 0); 301 | if(ip == 0){ 302 | end_op(); 303 | return -1; 304 | } 305 | } else { 306 | if((ip = namei(path)) == 0){ 307 | end_op(); 308 | return -1; 309 | } 310 | ilock(ip); 311 | if(ip->type == T_DIR && omode != O_RDONLY){ 312 | iunlockput(ip); 313 | end_op(); 314 | return -1; 315 | } 316 | } 317 | 318 | if((f = filealloc()) == 0 || (fd = fdalloc(f)) < 0){ 319 | if(f) 320 | fileclose(f); 321 | iunlockput(ip); 322 | end_op(); 323 | return -1; 324 | } 325 | iunlock(ip); 326 | end_op(); 327 | 328 | f->type = FD_INODE; 329 | f->ip = ip; 330 | f->off = 0; 331 | f->readable = !(omode & O_WRONLY); 332 | f->writable = (omode & O_WRONLY) || (omode & O_RDWR); 333 | return fd; 334 | } 335 | 336 | int 337 | sys_mkdir(void) 338 | { 339 | char *path; 340 | struct inode *ip; 341 | 342 | begin_op(); 343 | if(argstr(0, &path) < 0 || (ip = create(path, T_DIR, 0, 0)) == 0){ 344 | end_op(); 345 | return -1; 346 | } 347 | iunlockput(ip); 348 | end_op(); 349 | return 0; 350 | } 351 | 352 | int 353 | sys_mknod(void) 354 | { 355 | struct inode *ip; 356 | char *path; 357 | int major, minor; 358 | 359 | begin_op(); 360 | if((argstr(0, &path)) < 0 || 361 | argint(1, &major) < 0 || 362 | argint(2, &minor) < 0 || 363 | (ip = create(path, T_DEV, major, minor)) == 0){ 364 | end_op(); 365 | return -1; 366 | } 367 | iunlockput(ip); 368 | end_op(); 369 | return 0; 370 | } 371 | 372 | int 373 | sys_chdir(void) 374 | { 375 | char *path; 376 | struct inode *ip; 377 | struct proc *curproc = myproc(); 378 | 379 | begin_op(); 380 | if(argstr(0, &path) < 0 || (ip = namei(path)) == 0){ 381 | end_op(); 382 | return -1; 383 | } 384 | ilock(ip); 385 | if(ip->type != T_DIR){ 386 | iunlockput(ip); 387 | end_op(); 388 | return -1; 389 | } 390 | iunlock(ip); 391 | iput(curproc->cwd); 392 | end_op(); 393 | curproc->cwd = ip; 394 | return 0; 395 | } 396 | 397 | int 398 | sys_exec(void) 399 | { 400 | char *path, *argv[MAXARG]; 401 | int i; 402 | uint uargv, uarg; 403 | 404 | if(argstr(0, &path) < 0 || argint(1, (int*)&uargv) < 0){ 405 | return -1; 406 | } 407 | memset(argv, 0, sizeof(argv)); 408 | for(i=0;; i++){ 409 | if(i >= NELEM(argv)) 410 | return -1; 411 | if(fetchint(uargv+4*i, (int*)&uarg) < 0) 412 | return -1; 413 | if(uarg == 0){ 414 | argv[i] = 0; 415 | break; 416 | } 417 | if(fetchstr(uarg, &argv[i]) < 0) 418 | return -1; 419 | } 420 | return exec(path, argv); 421 | } 422 | 423 | int 424 | sys_pipe(void) 425 | { 426 | int *fd; 427 | struct file *rf, *wf; 428 | int fd0, fd1; 429 | 430 | if(argptr(0, (void*)&fd, 2*sizeof(fd[0])) < 0) 431 | return -1; 432 | if(pipealloc(&rf, &wf) < 0) 433 | return -1; 434 | fd0 = -1; 435 | if((fd0 = fdalloc(rf)) < 0 || (fd1 = fdalloc(wf)) < 0){ 436 | if(fd0 >= 0) 437 | myproc()->ofile[fd0] = 0; 438 | fileclose(rf); 439 | fileclose(wf); 440 | return -1; 441 | } 442 | fd[0] = fd0; 443 | fd[1] = fd1; 444 | return 0; 445 | } 446 | --------------------------------------------------------------------------------