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

tip-bot for Denys Vlasenko
2015-03-27T11:47:47Z

Commit-ID: 47eb582e702880c302036d17341c7ea1a7dc2a53
Gitweb: http://git.kernel.org/tip/47eb582e702880c302036d17341c7ea1a7dc2a53
Author: Denys Vlasenko <dvlasenk@redhat.com>
AuthorDate: Wed, 25 Mar 2015 18:18:15 +0100
Committer: Ingo Molnar <mingo@kernel.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@redhat.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1427303896-24023-3-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.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