[PATCH v2] powerpc64[le]: Allocate extra stack frame on syscall.S

[Raphael M Zinsly]

LGTM

Reviewed-by: Raphael M Zinsly <rzinsly@linux.ibm.com>

On 15/12/2021 11:39, Matheus Castanho wrote:
> v1 was not working properly on hosts without scv support, so some tests were
> failing in such systems. This is fixed now in this new version.
> 
> --8<--
> 
> The syscall function does not allocate the extra stack frame for scv like other
> assembly syscalls using DO_CALL_SCV. So after commit d120fb9941 changed the
> offset that is used to save LR, syscall ended up using an invalid offset,
> causing regressions on powerpc64. So make sure the extra stack frame is
> allocated in syscall.S as well to make it consistent with other uses of
> DO_CALL_SCV and avoid similar issues in the future.
> 
> Tested on powerpc, powerpc64, and powerpc64le (with and without scv)
> ---
>   sysdeps/unix/sysv/linux/powerpc/syscall.S | 4 ++++
>   1 file changed, 4 insertions(+)
> 
> diff --git a/sysdeps/unix/sysv/linux/powerpc/syscall.S b/sysdeps/unix/sysv/linux/powerpc/syscall.S
> index a29652feaf..a5497c8370 100644
> --- a/sysdeps/unix/sysv/linux/powerpc/syscall.S
> +++ b/sysdeps/unix/sysv/linux/powerpc/syscall.S
> @@ -27,7 +27,11 @@ ENTRY (syscall)
>   	mr   r8,r9
>   #if defined(USE_PPC_SCV) && !IS_IN(rtld) && (defined(__PPC64__) || defined(__powerpc64__))
>   	CHECK_SCV_SUPPORT r9 0f
> +	stdu r1,-SCV_FRAME_SIZE(r1)
> +	cfi_adjust_cfa_offset(SCV_FRAME_SIZE)
>   	DO_CALL_SCV
> +	addi r1,r1,SCV_FRAME_SIZE
> +	cfi_adjust_cfa_offset(-SCV_FRAME_SIZE)
>   	RET_SCV
>   	b 1f
>   #endif
> 

-- 
Raphael Moreira Zinsly