linux-kernel - [tip:x86/asm] x86/asm/entry/64: Move retint

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Date:	Tue, 31 Mar 2015 05:37:00 -0700
From:	tip-bot for Denys Vlasenko <tipbot@...or.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	fweisbec@...il.com, tglx@...utronix.de, wad@...omium.org,
	rostedt@...dmis.org, ast@...mgrid.com, oleg@...hat.com,
	luto@...capital.net, hpa@...or.com, bp@...en8.de,
	dvlasenk@...hat.com, torvalds@...ux-foundation.org,
	mingo@...nel.org, keescook@...omium.org,
	linux-kernel@...r.kernel.org
Subject: [tip:x86/asm] x86/asm/entry/64:
  Move retint_kernel code block closer to its user

Commit-ID:  627276cb55f33e2dc56eab5b973937c128b7704c
Gitweb:     http://git.kernel.org/tip/627276cb55f33e2dc56eab5b973937c128b7704c
Author:     Denys Vlasenko <dvlasenk@...hat.com>
AuthorDate: Mon, 30 Mar 2015 20:09:31 +0200
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Tue, 31 Mar 2015 09:31:11 +0200

x86/asm/entry/64: Move retint_kernel code block closer to its user

The "retint_kernel" code block is misplaced. Since its logical
continuation is "retint_restore_args", it is more natural to
place it above that label. This also makes two jumps "short".

This change only moves code block around, without changing
logic.

This enables the next simplification: making
"retint_restore_args" label a local numeric 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/1427738975-7391-2-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 arch/x86/kernel/entry_64.S | 25 +++++++++++++------------
 1 file changed, 13 insertions(+), 12 deletions(-)

diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index dbfc8875..34d60c3 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -740,7 +740,19 @@ opportunistic_sysret_failed:
 	SWAPGS
 	jmp restore_args
 
-retint_restore_args:	/* return to kernel space */
+/* Returning to kernel space */
+#ifdef CONFIG_PREEMPT
+	/* Interrupts are off */
+	/* Check if we need preemption */
+ENTRY(retint_kernel)
+	cmpl	$0,PER_CPU_VAR(__preempt_count)
+	jnz	retint_restore_args
+	bt	$9,EFLAGS(%rsp)	/* interrupts were off? */
+	jnc	retint_restore_args
+	call	preempt_schedule_irq
+	jmp	exit_intr
+#endif
+retint_restore_args:
 	DISABLE_INTERRUPTS(CLBR_ANY)
 	/*
 	 * The iretq could re-enable interrupts:
@@ -830,17 +842,6 @@ retint_signal:
 	GET_THREAD_INFO(%rcx)
 	jmp retint_with_reschedule
 
-#ifdef CONFIG_PREEMPT
-	/* Returning to kernel space. Check if we need preemption */
-	/* rcx:	 threadinfo. interrupts off. */
-ENTRY(retint_kernel)
-	cmpl $0,PER_CPU_VAR(__preempt_count)
-	jnz  retint_restore_args
-	bt   $9,EFLAGS(%rsp)	/* interrupts off? */
-	jnc  retint_restore_args
-	call preempt_schedule_irq
-	jmp exit_intr
-#endif
 	CFI_ENDPROC
 END(common_interrupt)
 
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