Add backtrace functions for sandbox, including:
- os_backtrace() to collect addresses into a caller-supplied buffer
- os_backtrace_symbols() to convert addresses to symbol strings
- os_backtrace_symbols_free() to free the symbol array
The libbacktrace library (bundled with GCC) reads DWARF debug information
to provide detailed symbol resolution including function names (even for
static functions), source file paths, and line numbers.
The sandbox backtrace implementation wraps these OS functions to implement
the generic backtrace API (backtrace_init, backtrace_get_syms, etc.).
Enable it for just the 'sandbox' board. Add the library for the Rust
example too.
Co-developed-by: Claude <noreply@anthropic.com>
Signed-off-by: Simon Glass <simon.glass@canonical.com>
The U-Boot library can be used from Rust fairly easily. Add an example
for this, following along the lines of the existing ulib example.
Note that the new way of representing C strings is not used for now,
since it is not available in v1.75 of cargo, as shipped by Ubuntu 24.04
Co-developed-by: Claude <noreply@anthropic.com>
Co-developed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>
