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Subject[tip:x86/asm] x86-32: Avoid pipeline serialization in PTREGSCALL1 and 2
Commit-ID:  ce9119ad90b1caba550447bfcc0a21850558ca49
Gitweb: http://git.kernel.org/tip/ce9119ad90b1caba550447bfcc0a21850558ca49
Author: H. Peter Anvin <hpa@zytor.com>
AuthorDate: Wed, 9 Dec 2009 16:33:44 -0800
Committer: H. Peter Anvin <hpa@zytor.com>
CommitDate: Wed, 9 Dec 2009 16:33:44 -0800

x86-32: Avoid pipeline serialization in PTREGSCALL1 and 2

In the PTREGSCALL1 and 2 macros, we can trivially avoid an unnecessary
pipeline serialization, so do so.

In PTREGSCALLS3 this is much less clear-cut since we have to push a
new value to the stack. Leave it alone for now assuming it is as good
as it is going to be; may want to check on Atom or another in-order
x86 to see if we can do better.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Brian Gerst <brgerst@gmail.com>
LKML-Reference: <1260403316-5679-2-git-send-email-brgerst@gmail.com>
---
arch/x86/kernel/entry_32.S | 6 +++---
1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S
index 6492555..cb12b9b 100644
--- a/arch/x86/kernel/entry_32.S
+++ b/arch/x86/kernel/entry_32.S
@@ -735,15 +735,15 @@ ptregs_##name: \
ALIGN; \
ptregs_##name: \
leal 4(%esp),%edx; \
- movl PT_EBX(%edx),%eax; \
+ movl (PT_EBX+4)(%esp),%eax; \
jmp sys_##name;

#define PTREGSCALL2(name) \
ALIGN; \
ptregs_##name: \
leal 4(%esp),%ecx; \
- movl PT_ECX(%ecx),%edx; \
- movl PT_EBX(%ecx),%eax; \
+ movl (PT_ECX+4)(%esp),%edx; \
+ movl (PT_EBX+4)(%esp),%eax; \
jmp sys_##name;

#define PTREGSCALL3(name) \

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