Re: [PATCH] x86/vdso: Fix vDSO build if a retpoline is emitted

From: David Woodhouse
Date: Thu Aug 16 2018 - 15:45:06 EST

On Thu, 2018-08-16 at 12:41 -0700, Andy Lutomirski wrote:
> Currently, if the vDSO ends up containing an indirect branch or
> call, GCC will emit the "external thunk" style of retpoline, and it
> will fail to link.
> Fix it by building the vDSO with inline retpoline thunks.
> I haven't seen any reports of this triggering on an unpatched
> kernel.
> Cc: Matt Rickard <matt@xxxxxxxxxxxxxxx>
> Cc: Jason Vas Dias <jason.vas.dias@xxxxxxxxx>
> Cc: David Woodhouse <dwmw2@xxxxxxxxxxxxx>
> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
> Fixes: commit 76b043848fd2 ("x86/retpoline: Add initial retpoline support")
> Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx>

Acked-by: David Woodhouse <dwmw@xxxxxxxxxxxx>


Attachment: smime.p7s
Description: S/MIME cryptographic signature