linux-kernel - [tip:x86/asm] x86-64: Slightly shorten int_ret_from_sys

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Message-ID: <tip-70ea6855d368588a7f1b0242ab83ca6fe2e2ff16@git.kernel.org>
Date:	Mon, 5 Dec 2011 10:00:14 -0800
From:	tip-bot for Jan Beulich <JBeulich@...e.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, hpa@...or.com, mingo@...hat.com,
	jbeulich@...e.com, JBeulich@...e.com, ak@...ux.intel.com,
	tglx@...utronix.de, mingo@...e.hu
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@...e.com>
AuthorDate: Tue, 29 Nov 2011 10:54:22 +0000
Committer:  Ingo Molnar <mingo@...e.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@...e.com>
Reviewed-by: Andi Kleen <ak@...ux.intel.com>
Link: http://lkml.kernel.org/r/4ED4C7EE0200007800064028@nat28.tlf.novell.com
Signed-off-by: Ingo Molnar <mingo@...e.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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