Re: [PATCH v5] gdb: align siginfo_t with the Linux kernel definition

[Matthieu Longo <matthieu.longo@arm.com>]

On 28/07/2026 13:32, Matthieu Longo wrote:
> GDB's current definition of siginfo_t is missing many fields present in
> the Linux kernel definition [1].
> 
> These fields are useful for providing detailed, user-friendly diagnostics
> when a fault occurs. Some new AArch64 extensions, such as Permission
> Overlay Enhancement used to implement Protection Keys [2], require the
> debugger to inspect 'si_pkey' alongside 'si_addr' to help the user identify
> the problematic key.
> 
> This patch aligns GDB's definition of the __sifields._sigfault member of
> siginfo_t with the definition from the Linux kernel master branch.
> 
> To avoid hardcoding the field access paths throughout the codebase, this
> patch also introduces compile-time accessors for the siginfo_t attributes,
> centralizing their definitions in a single location and making future
> updates easier.
> 
> Finally, extend the testsuite to verify access to the new si_pkey field
> and its preservation when modifying $_siginfo and when reading core files.
> The tests in siginfo-obj.exp rely on the siginfo_t definition provided by
> glibc's <signal.h>, which does not yet expose all of the fields present in
> the kernel definition. As a result, the tests cannot exercise every newly
> added field and therefore focus on si_pkey, the field motivating this change.
> The test validates that GDB can read and modify the field correctly; it does
> not attempt to generate a real protection-key fault.
> 
> [1]: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/
>      tree/include/uapi/asm-generic/siginfo.h#n69
> [2]: https://lore.kernel.org/all/20160212210213.ABC488FA@viggo.jf.intel.com/
> 
> Reviewed-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
Ping.

@Luis: I addressed your suggestion for compile time accessors. I think that it is cleaner than a
hard-coded string anyway. Please let me know what you if you are happy with the current state.

Regarding the GDB users' accessors, I haven't implemented them because the scope of this patch would
increase too much. Please see my response in v3 [1].

[1]: https://inbox.sourceware.org/gdb-patches/5c623005-2b19-48a6-9bd5-bb3dfb3166b0@arm.com/

Matthieu