linux-kernel - [tip:x86/asm] x86/asm/entry/64: Use smaller instructions

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Date:	Fri, 27 Mar 2015 04:47:00 -0700
From:	tip-bot for Denys Vlasenko <tipbot@...or.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	fweisbec@...il.com, oleg@...hat.com, wad@...omium.org,
	luto@...capital.net, tglx@...utronix.de, ast@...mgrid.com,
	bp@...en8.de, dvlasenk@...hat.com, rostedt@...dmis.org,
	torvalds@...ux-foundation.org, hpa@...or.com,
	linux-kernel@...r.kernel.org, keescook@...omium.org,
	mingo@...nel.org
Subject: [tip:x86/asm] x86/asm/entry/64: Use smaller instructions

Commit-ID:  47eb582e702880c302036d17341c7ea1a7dc2a53
Gitweb:     http://git.kernel.org/tip/47eb582e702880c302036d17341c7ea1a7dc2a53
Author:     Denys Vlasenko <dvlasenk@...hat.com>
AuthorDate: Wed, 25 Mar 2015 18:18:15 +0100
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Fri, 27 Mar 2015 09:57:06 +0100

x86/asm/entry/64: Use smaller instructions

The $AUDIT_ARCH_X86_64 parameter to syscall_trace_enter_phase1/2
is a 32-bit constant, loading it with 32-bit MOV produces 5-byte
insn instead of 10-byte MOVABS one.

Signed-off-by: Denys Vlasenko <dvlasenk@...hat.com>
Cc: Alexei Starovoitov <ast@...mgrid.com>
Cc: Andy Lutomirski <luto@...capital.net>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Frederic Weisbecker <fweisbec@...il.com>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Kees Cook <keescook@...omium.org>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Oleg Nesterov <oleg@...hat.com>
Cc: Steven Rostedt <rostedt@...dmis.org>
Cc: Will Drewry <wad@...omium.org>
Link: http://lkml.kernel.org/r/1427303896-24023-3-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 arch/x86/kernel/entry_64.S | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 9988c4b..f85d2cc 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -305,7 +305,7 @@ system_call_fastpath:
 	/* Do syscall entry tracing */
 tracesys:
 	movq %rsp, %rdi
-	movq $AUDIT_ARCH_X86_64, %rsi
+	movl $AUDIT_ARCH_X86_64, %esi
 	call syscall_trace_enter_phase1
 	test %rax, %rax
 	jnz tracesys_phase2		/* if needed, run the slow path */
@@ -316,7 +316,7 @@ tracesys:
 tracesys_phase2:
 	SAVE_EXTRA_REGS
 	movq %rsp, %rdi
-	movq $AUDIT_ARCH_X86_64, %rsi
+	movl $AUDIT_ARCH_X86_64, %esi
 	movq %rax,%rdx
 	call syscall_trace_enter_phase2
 
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