Re: [PATCH 1/1] gdb, gdbserver: Add Intel APX register support

[Keith Seitz <keiths@redhat.com>]

On 8/25/26 9:11 AM, Joos, Christina wrote:
> I just found a bug in this area:
> https://sourceware.org/bugzilla/show_bug.cgi?id=34561
> 
> Assuming a fix like the one indicated in comment of the bug will be merged
> before this patch I think we can add something like this on top:
> 
> ~~~
> diff --git a/gdb/i387-tdep.c b/gdb/i387-tdep.c
> index 51459c31dcc..51180714e08 100644
> --- a/gdb/i387-tdep.c
> +++ b/gdb/i387-tdep.c
> @@ -955,6 +955,8 @@ i387_guess_xsave_layout (uint64_t xcr0, size_t xsave_size,
>           Otherwise, we are not able to read xsave registers in OS generated
>           corefiles.  */
>         layout.avx_offset = 576;
> +      /* Intel APX can be available on CPUs with PKRU including AMX or not
> +        including AMX support.  */
>         layout.apx_offset = 960;
>         layout.k_offset = 1088;
>         layout.zmm_h_offset = 1152;
> @@ -974,6 +976,7 @@ i387_guess_xsave_layout (uint64_t xcr0, size_t xsave_size,
>       {
>         /* Intel CPUs supporting AVX512.  */
>         layout.avx_offset = 576;
> +      /* Intel APX can be available on CPUs supporting AVX512.  */
>         layout.apx_offset = 960;
>         layout.k_offset = 1088;
>         layout.zmm_h_offset = 1152;
> ~~~
> 
> Or do you have a different comment in mind?

I am satisfied with that. Thank you.

> My original plan was to post this patch once again including the fixes for Eli's
> feedback + ones pointed out by me here
> https://sourceware.org/pipermail/gdb-patches/2026-August/229759.html
> and then wait 1-2 weeks and merge it if there is no more feedback.
> Since it's only in the x86 area I think it should be fine for me to self-approve here.
>   
> However, in the meantime this bug mentioned above popped up.
> I think it makes sense to wait until this is resolved.
FWIW, I think you've got a better handle on all of the issues
at play than I do, so I trust you'll Do The Right Thing (TM).

Keith