Subject: Re: [v2, 2/2] powerpc/vdso: Avoid link stack corruption in __get_datapage()

From: Benjamin Herrenschmidt <[email-masked]>
Date: Fri, 02 Oct 2015 18:24:50 +1000

On Fri, 2015-10-02 at 17:47 +1000, Michael Ellerman wrote:
> On Fri, 2015-25-09 at 04:01:40 UTC, Michael Neuling wrote:
> > powerpc has a link register (lr) used for calling functions. We "bl
> > <func>" to call a function, and "blr" to return back to the call
> > site.
> 
> <snip, geez that was long>
> 
> > For the benchmark in
> > tools/testing/selftests/powerpc/benchmarks/gettimeofday.c
> >   POWER8:
> >     64bit gets ~4% improvement
> >     32bit gets ~9% improvement
> >   POWER7:
> >     64bit gets ~7% improvement
> > 
> > Signed-off-by: Michael Neuling <[email-masked]>
> > Reported-by: Aaron Sawdey <[email-masked]>
> 
> Applied to powerpc next, thanks.
> 
> https://git.kernel.org/powerpc/c/c974809a26a13e40254dbe3c

I'd argue this is a bug fix and should hit stable too..

Cheers,
Ben.