[tip:x86/asm] x86/entry/32: Relax a pvops stub clobber specification

From: tip-bot for Jan Beulich
Date: Wed Mar 01 2017 - 04:51:24 EST


Commit-ID: fdbd518adfaf2c10903250dffe70c61ed90b7dd7
Gitweb: http://git.kernel.org/tip/fdbd518adfaf2c10903250dffe70c61ed90b7dd7
Author: Jan Beulich <JBeulich@xxxxxxxx>
AuthorDate: Fri, 3 Feb 2017 01:58:03 -0700
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Wed, 1 Mar 2017 10:16:30 +0100

x86/entry/32: Relax a pvops stub clobber specification

The code at .Lrestore_nocheck does not make any assumptions on register
values, so all registers can be clobbered on code paths leading there.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/5894542B02000078001366C5@xxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/entry/entry_32.S | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
index 57f7ec3..5553475 100644
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -585,7 +585,7 @@ ENTRY(iret_exc )
* will soon execute iret and the tracer was already set to
* the irqstate after the IRET:
*/
- DISABLE_INTERRUPTS(CLBR_EAX)
+ DISABLE_INTERRUPTS(CLBR_ANY)
lss (%esp), %esp /* switch to espfix segment */
jmp .Lrestore_nocheck
#endif