lkml.org 
[lkml]   [2012]   [Nov]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] x86, kvm: Remove incorrect redundant assembly constraint
On Mon, Nov 26, 2012 at 02:48:50PM -0800, H. Peter Anvin wrote:
> On 11/25/2012 11:22 PM, Paolo Bonzini wrote:
> > Il 21/11/2012 23:41, H. Peter Anvin ha scritto:
> >> From: "H. Peter Anvin" <hpa@linux.intel.com>
> >>
> >> In __emulate_1op_rax_rdx, we use "+a" and "+d" which are input/output
> >> constraints, and *then* use "a" and "d" as input constraints. This is
> >> incorrect, but happens to work on some versions of gcc.
> >>
> >> However, it breaks gcc with -O0 and icc, and may break on future
> >> versions of gcc.
> >>
> >> Reported-and-tested-by: Melanie Blower <melanie.blower@intel.com>
> >> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
> >> Link: http://lkml.kernel.org/r/B3584E72CFEBED439A3ECA9BCE67A4EF1B17AF90@FMSMSX107.amr.corp.intel.com
> >> ---
> >> arch/x86/kvm/emulate.c | 3 +--
> >> 1 file changed, 1 insertion(+), 2 deletions(-)
> >>
> >> diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
> >> index 39171cb..bba39bf 100644
> >> --- a/arch/x86/kvm/emulate.c
> >> +++ b/arch/x86/kvm/emulate.c
> >> @@ -426,8 +426,7 @@ static void invalidate_registers(struct x86_emulate_ctxt *ctxt)
> >> _ASM_EXTABLE(1b, 3b) \
> >> : "=m" ((ctxt)->eflags), "=&r" (_tmp), \
> >> "+a" (*rax), "+d" (*rdx), "+qm"(_ex) \
> >> - : "i" (EFLAGS_MASK), "m" ((ctxt)->src.val), \
> >> - "a" (*rax), "d" (*rdx)); \
> >> + : "i" (EFLAGS_MASK), "m" ((ctxt)->src.val)); \
> >> } while (0)
> >>
> >> /* instruction has only one source operand, destination is implicit (e.g. mul, div, imul, idiv) */
> >>
> >
> > Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
> >
>
> Gleb, Marcelo: are you going to apply this or would you prefer I took it
> in x86/urgent?
>
> -hpa

Feel free to merge it through x86/urgent.



\
 
 \ /
  Last update: 2012-11-27 01:01    [W:0.053 / U:0.172 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site