panic-persistWrites panic messages to a section of RAM
This crate contains an implementation of panic_fmt that logs panic messages to a region of
RAM defined by the user, so that these messages can be retrieved on next boot, and handled
outside of panic context, by sending to a logging interface, writing to flash, etc.
After logging the message to RAM, the device will be soft-reset automatically.
Unlike other methods this allows to discover the panic reason post-mortem using normal program control flow.
Currently this crate was only tested on ARM Cortex-M architecture but should be easily portable to other platforms as required.
You will need to reserve a section of RAM to be used to persist messages. This section must be large enough to hold the 8 byte header, as well as any panic messages you would like to persist. If there is not suitable space in the section, the panic message will be truncated.
This section should be outside of any other sections, to prevent program initialization from zeroing or otherwise modifying these sections on boot.
memory.x file before modification:
text
MEMORY
{
/* NOTE K = KiBi = 1024 bytes */
FLASH : ORIGIN = 0x00000000, LENGTH = 512K
RAM : ORIGIN = 0x20000000, LENGTH = 64K
}
memory.x file after modification to hold a 1K region:
```text MEMORY { /* NOTE K = KiBi = 1024 bytes */ FLASH : ORIGIN = 0x00000000, LENGTH = 512K RAM : ORIGIN = 0x20000000, LENGTH = 63K PANDUMP: ORIGIN = 0x2000FC00, LENGTH = 1K }
panicdumpstart = ORIGIN(PANDUMP); _panicdump_end = ORIGIN(PANDUMP) + LENGTH(PANDUMP); ```
```rust
use panic_persist as _;
fn main() -> ! { // Normal board setup...
// Check if there was a panic message, if so, send to UART
if let Some(msg) = get_panic_message_bytes() {
board.uart.write(msg);
}
// ...
} ```
There is one optional feature, utf8. This allows the panic message to be returned
as a &str rather than &[u8], for easier printing. As this requires the ability
to validate the UTF-8 string (to ensure it wasn't truncated mid-character), it may
increase code size usage, and is by default off.
This crate was inspired (and forked from) the [panic-ramdump] crate.
Licensed under either of
at your option.
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.