[PATCH] S390: Fix backtrace in vdso functions.

[Adhemerval Zanella]

On 28/11/2017 12:18, Florian Weimer wrote:
> On 11/28/2017 02:09 PM, Adhemerval Zanella wrote:
>> I am almost sure we can remove it for powerpc as well (I can't see
>> no immediate gain on doing a function call using inline assembly
>> as for INTERNAL_VSYSCALL_NO_SYSCALL_FALLBACK on powerpc).
> 
> Is there another way to obtain the condition code for the error status?
> 
>   /* The vDSO does not return an error (it clear cr0.so on returning).  */
> Â  INTERNAL_SYSCALL_DECL (err);
> Â  result =
> Â Â Â  INTERNAL_VSYSCALL_NO_SYSCALL_FALLBACK (get_tbfreq, err, uint64_t, 0);
> 
> Thanks,
> Florian

I think we can simplify this call in specific since __kernel_get_tbfreq
always succeed if the vDSO is present. The only issue is the symbol
returns an uint64_t even for powerpc32.