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Subject[tip:x86/asm] x86-64: Slightly shorten int_ret_from_sys_call
Commit-ID:  70ea6855d368588a7f1b0242ab83ca6fe2e2ff16
Gitweb: http://git.kernel.org/tip/70ea6855d368588a7f1b0242ab83ca6fe2e2ff16
Author: Jan Beulich <JBeulich@suse.com>
AuthorDate: Tue, 29 Nov 2011 10:54:22 +0000
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Mon, 5 Dec 2011 17:24:37 +0100

x86-64: Slightly shorten int_ret_from_sys_call

Testing for a return to ring 0 was necessary here solely because
of the branch out of ret_from_fork. That branch, however, can be
directed to retint_restore_args, and thus the test-and-branch
can be eliminated here.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/4ED4C7EE0200007800064028@nat28.tlf.novell.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
arch/x86/kernel/entry_64.S | 4 +---
1 files changed, 1 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index faf8d5e..ab4b7ff 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -411,7 +411,7 @@ ENTRY(ret_from_fork)
RESTORE_REST

testl $3, CS-ARGOFFSET(%rsp) # from kernel_thread?
- je int_ret_from_sys_call
+ jz retint_restore_args

testl $_TIF_IA32, TI_flags(%rcx) # 32-bit compat task needs IRET
jnz int_ret_from_sys_call
@@ -612,8 +612,6 @@ tracesys:
GLOBAL(int_ret_from_sys_call)
DISABLE_INTERRUPTS(CLBR_NONE)
TRACE_IRQS_OFF
- testl $3,CS-ARGOFFSET(%rsp)
- je retint_restore_args
movl $_TIF_ALLWORK_MASK,%edi
/* edi: mask to check */
GLOBAL(int_with_check)

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