Messages in this thread Patch in this message | | | Date | Mon, 26 Nov 2012 16:01:38 -0800 | From | "tip-bot for H. Peter Anvin" <> | Subject | [tip:x86/urgent] x86, kvm: Remove incorrect redundant assembly constraint |
| |
Commit-ID: cb7cb2864e758a1b040040bc55e404c677c911cb Gitweb: http://git.kernel.org/tip/cb7cb2864e758a1b040040bc55e404c677c911cb Author: H. Peter Anvin <hpa@linux.intel.com> AuthorDate: Wed, 21 Nov 2012 14:41:21 -0800 Committer: H. Peter Anvin <hpa@linux.intel.com> CommitDate: Mon, 26 Nov 2012 15:52:48 -0800
x86, kvm: Remove incorrect redundant assembly constraint
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 Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Acked-by: Marcelo Tosatti <mtosatti@redhat.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) */
| |