Re: [PATCH] alpha: add simd_enabled argument to perf_reg_validate()

[Magnus Lindholm]

Hi Thomas,

On Wed, Oct 21, 2026 at 10:18 AM Thomas Weißschuh
<thomas.weissschuh@xxxxxxxxxxxxx> wrote:
>
> Align the alpha function with the generic function signature.
> The alpha function was added in commit 9280e99d87dd ("alpha: add
> HAVE_PERF_REGS and HAVE_PERF_USER_STACK_DUMP support") while the
> generic function signature was changed in commit a2c64c74c029 ("perf:
> Enhance perf_reg_validate() with simd_enabled argument").
>
> After both commits landed in Linus' tree the signatures now differ,
> resulting in a build error:
>
> arch/alpha/kernel/perf_regs.c:46:5: error: conflicting types for 'perf_reg_validate'; have 'int(u64)' {aka 'int(long long unsigned int)'}
>    46 | int perf_reg_validate(u64 mask)
>       |     ^~~~~~~~~~~~~~~~~
> In file included from include/linux/perf_event.h:50,
>                  from arch/alpha/kernel/perf_regs.c:4:
> include/linux/perf_regs.h:13:5: note: previous declaration of 'perf_reg_validate' with type 'int(u64,  bool)' {aka 'int(long long unsigned int,  _Bool)'}
>    13 | int perf_reg_validate(u64 mask, bool simd_enabled);
>       |     ^~~~~~~~~~~~~~~~~
>
> Add the missing argument.
>
> Fixes: 742f62b63904 ("Merge tag 'alpha-for-v7.4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/lindholm/alpha")
> Signed-off-by: Thomas Weißschuh <thomas.weissschuh@xxxxxxxxxxxxx>
> ---
>  arch/alpha/kernel/perf_regs.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/alpha/kernel/perf_regs.c b/arch/alpha/kernel/perf_regs.c
> index 33ea2e831ba0..c5a55bfa15a5 100644
> --- a/arch/alpha/kernel/perf_regs.c
> +++ b/arch/alpha/kernel/perf_regs.c
> @@ -43,7 +43,7 @@ u64 perf_reg_value(struct pt_regs *regs, int idx)
>         return *(unsigned long *)((void *)regs + pt_regs_offset[idx]);
>  }
>
> -int perf_reg_validate(u64 mask)
> +int perf_reg_validate(u64 mask, bool simd_enabled)
>  {
>         if (!mask || mask & REG_RESERVED)
>                 return -EINVAL;
>
> ---
> base-commit: 2c455ddca7827ad8fa3a64fdbf5a60efb928b46a
> change-id: 20261021-alpha-perf_reg_validate-c9b0a144fd3c
>
> Best regards,
> --
> Thomas Weißschuh <thomas.weissschuh@xxxxxxxxxxxxx>
>

Thanks for catching this. I reproduced the build failure on current
mainline and confirmed your fix with GENERIC SMP and DP264 UP builds.
Both also passed perf register validation and sampling tests in QEMU.

Reviewed-by: Magnus Lindholm <linmag7@xxxxxxxxx>
Tested-by: Magnus Lindholm <linmag7@xxxxxxxxx>

If you have a route for this patch upstream, please go ahead and take it,
unless Linus would prefer to pick it up directly.


Thanks,
Magnus