├── .gitignore ├── .travis.yml ├── CHANGELOG.md ├── Cargo.toml ├── LICENSE-APACHE ├── LICENSE-MIT ├── README.md └── src └── lib.rs /.gitignore: -------------------------------------------------------------------------------- 1 | **/*.rs.bk 2 | .#* 3 | /target 4 | Cargo.lock 5 | -------------------------------------------------------------------------------- /.travis.yml: -------------------------------------------------------------------------------- 1 | language: rust 2 | rust: 3 | - stable 4 | - nightly 5 | cache: cargo 6 | matrix: 7 | allow_failures: 8 | - rust: nightly 9 | fast_finish: true 10 | script: 11 | - rustup target add thumbv7m-none-eabi 12 | - cargo build 13 | -------------------------------------------------------------------------------- /CHANGELOG.md: -------------------------------------------------------------------------------- 1 | # Change Log 2 | 3 | All notable changes to this project will be documented in this file. 4 | 5 | The format is based on [Keep a Changelog](http://keepachangelog.com/) 6 | and this project adheres to [Semantic Versioning](http://semver.org/). 7 | 8 | ## [Unreleased] 9 | 10 | ## [v0.2.1] 11 | 12 | - Added docs.rs metadata to show all features 13 | 14 | ## v0.2.0 15 | 16 | - Initial Release 17 | 18 | [v0.2.1]: https://github.com/therealprof/panic-ramdump/compare/v0.2.0...v0.2.1 19 | [Unreleased]: https://github.com/therealprof/panic-ramdump/compare/v0.2.1...HEAD 20 | -------------------------------------------------------------------------------- /Cargo.toml: -------------------------------------------------------------------------------- 1 | [package] 2 | edition = "2018" 3 | authors = [ 4 | "James Munns ", 5 | ] 6 | categories = ["embedded", "no-std"] 7 | description = "Persist panic messages in the targets' RAM" 8 | documentation = "https://docs.rs/panic-persist" 9 | keywords = ["panic-handler", "panic-impl", "panic", "persist"] 10 | license = "MIT OR Apache-2.0" 11 | name = "panic-persist" 12 | repository = "https://github.com/jamesmunns/panic-persist" 13 | version = "0.3.0" 14 | readme = "README.md" 15 | 16 | [dependencies] 17 | cortex-m = "0.7.2" 18 | 19 | [features] 20 | default = [] 21 | utf8 = [] 22 | custom-panic-handler = [] 23 | min-panic = [] 24 | 25 | [package.metadata.docs.rs] 26 | all-features = true 27 | -------------------------------------------------------------------------------- /LICENSE-APACHE: -------------------------------------------------------------------------------- 1 | Apache License 2 | Version 2.0, January 2004 3 | http://www.apache.org/licenses/ 4 | 5 | TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 6 | 7 | 1. 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IN NO EVENT 23 | SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY 24 | CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION 25 | OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR 26 | IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 27 | DEALINGS IN THE SOFTWARE. 28 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # `panic-persist` 2 | 3 | Writes panic messages to a section of RAM 4 | 5 | This crate contains an implementation of `panic_fmt` that logs panic messages to a region of 6 | RAM defined by the user, so that these messages can be retrieved on next boot, and handled 7 | outside of panic context, by sending to a logging interface, writing to flash, etc. 8 | 9 | After logging the message to RAM, the device will be soft-reset automatically. 10 | 11 | Unlike other methods this allows to discover the panic reason post-mortem using normal program 12 | control flow. 13 | 14 | Currently this crate was only tested on ARM Cortex-M architecture but should be easily portable 15 | to other platforms as required. 16 | 17 | ## [Documentation](https://docs.rs/panic-persist) 18 | 19 | ## Usage 20 | 21 | ### Add a section to your linker script 22 | 23 | You will need to reserve a section of RAM to be used to persist messages. This section must be 24 | large enough to hold the 8 byte header, as well as any panic messages you would like to persist. 25 | If there is not suitable space in the section, the panic message will be truncated. 26 | 27 | This section should be outside of any other sections, to prevent program initialization from 28 | zeroing or otherwise modifying these sections on boot. 29 | 30 | `memory.x` file before modification: 31 | 32 | ```text 33 | MEMORY 34 | { 35 | /* NOTE K = KiBi = 1024 bytes */ 36 | FLASH : ORIGIN = 0x00000000, LENGTH = 512K 37 | RAM : ORIGIN = 0x20000000, LENGTH = 64K 38 | } 39 | ``` 40 | 41 | `memory.x` file after modification to hold a 1K region: 42 | 43 | ```text 44 | MEMORY 45 | { 46 | /* NOTE K = KiBi = 1024 bytes */ 47 | FLASH : ORIGIN = 0x00000000, LENGTH = 512K 48 | RAM : ORIGIN = 0x20000000, LENGTH = 63K 49 | PANDUMP: ORIGIN = 0x2000FC00, LENGTH = 1K 50 | } 51 | 52 | _panic_dump_start = ORIGIN(PANDUMP); 53 | _panic_dump_end = ORIGIN(PANDUMP) + LENGTH(PANDUMP); 54 | ``` 55 | 56 | 57 | ### Program Usage Example 58 | 59 | ```rust 60 | #![no_std] 61 | 62 | use panic_persist as _; 63 | 64 | #[entry] 65 | fn main() -> ! { 66 | // Normal board setup... 67 | 68 | // Check if there was a panic message, if so, send to UART 69 | if let Some(msg) = get_panic_message_bytes() { 70 | board.uart.write(msg); 71 | } 72 | 73 | // ... 74 | } 75 | ``` 76 | 77 | ## Features 78 | 79 | There are a few optional features, `utf8` and `custom-panic-handler`. 80 | 81 | ### utf8 82 | 83 | This allows the panic message to be returned 84 | as a `&str` rather than `&[u8]`, for easier printing. As this requires the ability 85 | to validate the UTF-8 string (to ensure it wasn't truncated mid-character), it may 86 | increase code size usage, and is by default off. 87 | 88 | ### custom-panic-handler 89 | 90 | This disables the panic handler from this library so that any user can implement their own. 91 | To persist panic messages, the function `report_panic_info` is made available; 92 | 93 | ```rust 94 | // My custom panic implementation 95 | #[panic_handler] 96 | fn panic(info: &PanicInfo) -> ! { 97 | // ... 98 | panic_persist::report_panic_info(info); 99 | // ... 100 | } 101 | ``` 102 | 103 | ### min-panic 104 | 105 | This prints a smaller, line-number-only message, in order to reduce space needed when persisting panics, at a loss of some context. 106 | 107 | ## Provenance 108 | 109 | This crate was inspired (and forked from) the [`panic-ramdump`] crate. 110 | 111 | [`panic-ramdump`]: https://github.com/therealprof/panic-ramdump 112 | 113 | ## License 114 | 115 | Licensed under either of 116 | 117 | - Apache License, Version 2.0 ([LICENSE-APACHE](LICENSE-APACHE) or 118 | http://www.apache.org/licenses/LICENSE-2.0) 119 | - MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT) 120 | 121 | at your option. 122 | 123 | ### Contribution 124 | 125 | Unless you explicitly state otherwise, any contribution intentionally submitted 126 | for inclusion in the work by you, as defined in the Apache-2.0 license, shall be 127 | dual licensed as above, without any additional terms or conditions. 128 | -------------------------------------------------------------------------------- /src/lib.rs: -------------------------------------------------------------------------------- 1 | //! # `panic-persist` 2 | //! 3 | //! Writes panic messages to a section of RAM 4 | //! 5 | //! This crate contains an implementation of `panic_fmt` that logs panic messages to a region of 6 | //! RAM defined by the user, so that these messages can be retrieved on next boot, and handled 7 | //! outside of panic context, by sending to a logging interface, writing to flash, etc. 8 | //! 9 | //! After logging the message to RAM, the device will be soft-reset automatically. 10 | //! 11 | //! Unlike other methods this allows to discover the panic reason post-mortem using normal program 12 | //! control flow. 13 | //! 14 | //! Currently this crate was only tested on ARM Cortex-M architecture but should be easily portable 15 | //! to other platforms as required. 16 | //! 17 | //! ## Usage 18 | //! 19 | //! ### Add a section to your linker script 20 | //! 21 | //! You will need to reserve a section of RAM to be used to persist messages. This section must be 22 | //! large enough to hold the 8 byte header, as well as any panic messages you would like to persist. 23 | //! If there is not suitable space in the section, the panic message will be truncated. 24 | //! 25 | //! This section should be outside of any other sections, to prevent program initialization from 26 | //! zeroing or otherwise modifying these sections on boot. 27 | //! 28 | //! `memory.x` file before modification: 29 | //! 30 | //! ``` ignore 31 | //! MEMORY 32 | //! { 33 | //! /* NOTE K = KiBi = 1024 bytes */ 34 | //! FLASH : ORIGIN = 0x00000000, LENGTH = 512K 35 | //! RAM : ORIGIN = 0x20000000, LENGTH = 64K 36 | //! } 37 | //! ``` 38 | //! 39 | //! `memory.x` file after modification to hold a 1K region: 40 | //! 41 | //! ``` ignore 42 | //! MEMORY 43 | //! { 44 | //! /* NOTE K = KiBi = 1024 bytes */ 45 | //! FLASH : ORIGIN = 0x00000000, LENGTH = 512K 46 | //! RAM : ORIGIN = 0x20000000, LENGTH = 63K 47 | //! PANDUMP: ORIGIN = 0x2000FC00, LENGTH = 1K 48 | //! } 49 | //! 50 | //! _panic_dump_start = ORIGIN(PANDUMP); 51 | //! _panic_dump_end = ORIGIN(PANDUMP) + LENGTH(PANDUMP); 52 | //! ``` 53 | //! 54 | //! 55 | //! ### Program Usage Example 56 | //! 57 | //! ``` ignore 58 | //! #![no_std] 59 | //! 60 | //! use panic_persist as _; 61 | //! 62 | //! #[entry] 63 | //! fn main() -> ! { 64 | //! // Normal board setup... 65 | //! 66 | //! // Check if there was a panic message, if so, send to UART 67 | //! if let Some(msg) = get_panic_message_bytes() { 68 | //! board.uart.write(msg); 69 | //! } 70 | //! 71 | //! // ... 72 | //! } 73 | //! ``` 74 | //! 75 | //! ## Features 76 | //! 77 | //! There are a few optional features, `utf8` and `custom-panic-handler`. 78 | //! 79 | //! ### utf8 80 | //! 81 | //! This allows the panic message to be returned 82 | //! as a `&str` rather than `&[u8]`, for easier printing. As this requires the ability 83 | //! to validate the UTF-8 string (to ensure it wasn't truncated mid-character), it may 84 | //! increase code size usage, and is by default off. 85 | //! 86 | //! ### custom-panic-handler 87 | //! 88 | //! This disables the panic handler from this library so that any user can implement their own. 89 | //! To persist panic messages, the function `report_panic_info` is made available; 90 | //! 91 | //! ```rust 92 | //! // My custom panic implementation 93 | //! #[panic_handler] 94 | //! fn panic(info: &PanicInfo) -> ! { 95 | //! // ... 96 | //! panic_persist::report_panic_info(info); 97 | //! // ... 98 | //! } 99 | //! ``` 100 | //! 101 | //! ### min-panic 102 | //! 103 | //! This prints a smaller, line-number-only message, in order to reduce space needed when persisting panics, at a loss of some context. 104 | 105 | #![allow(clippy::empty_loop)] 106 | #![deny(missing_docs)] 107 | #![deny(warnings)] 108 | #![no_std] 109 | 110 | use core::cmp::min; 111 | use core::fmt::Write; 112 | use core::mem::size_of; 113 | use core::panic::PanicInfo; 114 | 115 | struct Ram { 116 | offset: usize, 117 | } 118 | 119 | /// Internal Write implementation to output the formatted panic string into RAM 120 | impl core::fmt::Write for Ram { 121 | fn write_str(&mut self, s: &str) -> Result<(), core::fmt::Error> { 122 | // Obtain panic region start and end from linker symbol _panic_dump_start and _panic_dump_end 123 | extern "C" { 124 | static mut _panic_dump_start: u8; 125 | static mut _panic_dump_end: u8; 126 | } 127 | 128 | // Get the data about the string that is being written now 129 | let data = s.as_bytes(); 130 | let len = data.len(); 131 | 132 | // Obtain info about the panic dump region 133 | let start_ptr = unsafe { &mut _panic_dump_start as *mut u8 }; 134 | let end_ptr = unsafe { &mut _panic_dump_end as *mut u8 }; 135 | let max_len = end_ptr as usize - start_ptr as usize; 136 | let max_len_str = max_len - size_of::() - size_of::(); 137 | 138 | // If we have written the full length of the region, we can't write any 139 | // more. This could happen with multiple writes with this implementation 140 | if self.offset >= max_len_str { 141 | return Ok(()); 142 | } 143 | 144 | // We should write the size of the string, or the amount of space 145 | // we have remaining, whichever is less 146 | let str_len = min(max_len_str - self.offset, len); 147 | 148 | unsafe { 149 | // Write the magic word for later detection 150 | start_ptr.cast::().write_unaligned(0x0FACADE0); 151 | 152 | // For now, skip writing the length... 153 | 154 | // Write the string to RAM 155 | core::ptr::copy( 156 | data.as_ptr() as *mut u8, 157 | start_ptr.offset(8).offset(self.offset as isize), 158 | str_len, 159 | ); 160 | 161 | // Increment the offset so later writes will be appended 162 | self.offset += str_len; 163 | 164 | // ... and now write the current offset (or total size) to the size location 165 | start_ptr 166 | .offset(4) 167 | .cast::() 168 | .write_unaligned(self.offset); 169 | }; 170 | 171 | Ok(()) 172 | } 173 | } 174 | 175 | /// Get the panic message from the last boot, if any. 176 | /// This method may possibly not return valid UTF-8 if the message 177 | /// was truncated before the end of a full UTF-8 character. Care must 178 | /// be taken before treating this as a proper &str. 179 | /// 180 | /// If a message existed, this function will only return the value once 181 | /// (subsequent calls will return None) 182 | pub fn get_panic_message_bytes() -> Option<&'static [u8]> { 183 | // Obtain panic region start and end from linker symbol _panic_dump_start and _panic_dump_end 184 | extern "C" { 185 | static mut _panic_dump_start: u8; 186 | static mut _panic_dump_end: u8; 187 | } 188 | 189 | let start_ptr = unsafe { &mut _panic_dump_start as *mut u8 }; 190 | 191 | if 0x0FACADE0 != unsafe { core::ptr::read_unaligned(start_ptr.cast::()) } { 192 | return None; 193 | } 194 | 195 | // Clear the magic word to prevent this message from "sticking" 196 | // across multiple boots 197 | unsafe { 198 | start_ptr.cast::().write_unaligned(0x00000000); 199 | } 200 | 201 | // Obtain info about the panic dump region 202 | let end_ptr = unsafe { &mut _panic_dump_end as *mut u8 }; 203 | let max_len = end_ptr as usize - start_ptr as usize; 204 | let max_len_str = max_len - size_of::() - size_of::(); 205 | 206 | let len = unsafe { core::ptr::read_unaligned(start_ptr.offset(4).cast::()) }; 207 | 208 | if len > max_len_str { 209 | return None; 210 | } 211 | 212 | // TODO: This is prooooooooobably undefined behavior 213 | let byte_slice = unsafe { core::slice::from_raw_parts(start_ptr.offset(8), len) }; 214 | 215 | Some(byte_slice) 216 | } 217 | 218 | /// Get the panic message from the last boot, if any. If any invalid 219 | /// UTF-8 characters occur, the message will be truncated before the 220 | /// first error. 221 | /// 222 | /// If a message existed, this function will only return the value once 223 | /// (subsequent calls will return None) 224 | #[cfg(feature = "utf8")] 225 | pub fn get_panic_message_utf8() -> Option<&'static str> { 226 | let bytes = get_panic_message_bytes()?; 227 | 228 | use core::str::from_utf8; 229 | 230 | match from_utf8(bytes) { 231 | Ok(stir) => Some(stir), 232 | Err(utf_err) => { 233 | match from_utf8(&bytes[..utf_err.valid_up_to()]) { 234 | Ok(stir) => Some(stir), 235 | Err(_) => { 236 | // This shouldn't be possible... 237 | None 238 | } 239 | } 240 | } 241 | } 242 | } 243 | 244 | /// Report the panic so the message is persisted. 245 | /// 246 | /// This function is used in custom panic handlers. 247 | #[cfg(feature = "custom-panic-handler")] 248 | pub fn report_panic_info(info: &PanicInfo) { 249 | writeln!(Ram { offset: 0 }, "{}", info).ok(); 250 | } 251 | 252 | #[cfg(not(feature = "custom-panic-handler"))] 253 | #[panic_handler] 254 | fn panic(info: &PanicInfo) -> ! { 255 | cortex_m::interrupt::disable(); 256 | 257 | #[cfg(feature = "min-panic")] 258 | if let Some(location) = info.location() { 259 | writeln!(Ram { offset: 0 }, "Panicked at {}", location).ok(); 260 | } else { 261 | writeln!(Ram { offset: 0 }, "Panic occured!").ok(); 262 | } 263 | 264 | #[cfg(not(feature = "min-panic"))] 265 | writeln!(Ram { offset: 0 }, "{}", info).ok(); 266 | 267 | cortex_m::peripheral::SCB::sys_reset(); 268 | } 269 | --------------------------------------------------------------------------------