[PATCH] x86-64/entry: fold identical code paths

[PATCH] x86-64/entry: fold identical code paths

[Jan Beulich]

retint_kernel doesn't require %rcx to be pointing to thread info
(anymore?), and the code on the two alternative paths is - not really
surprisingly - identical.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: Andy Lutomirski <luto@kernel.org>
---
 arch/x86/kernel/entry_64.S |   10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

--- 4.1-rc6/arch/x86/kernel/entry_64.S
+++ 4.1-rc6-x86_64-entry-fold-code/arch/x86/kernel/entry_64.S
@@ -744,7 +744,7 @@ ret_from_intr:
 	testl $3,CS(%rsp)
 	je retint_kernel
 	/* Interrupt came from user space */
-
+retint_user:
 	GET_THREAD_INFO(%rcx)
 	/*
 	 * %rcx: thread info. Interrupts off.
@@ -1380,15 +1380,9 @@ ENTRY(error_exit)
 	RESTORE_EXTRA_REGS
 	DISABLE_INTERRUPTS(CLBR_NONE)
 	TRACE_IRQS_OFF
-	GET_THREAD_INFO(%rcx)
 	testl %eax,%eax
 	jne retint_kernel
-	LOCKDEP_SYS_EXIT_IRQ
-	movl TI_flags(%rcx),%edx
-	movl $_TIF_WORK_MASK,%edi
-	andl %edi,%edx
-	jnz retint_careful
-	jmp retint_swapgs
+	jmp retint_user
 	CFI_ENDPROC
 END(error_exit)
 

[tip:x86/asm] x86/asm/entry/64: Fold identical code paths

[tip-bot for Jan Beulich]

Commit-ID:  2f63b9db7260beba3c19d66d6c11b0b78ea84a8c
Gitweb:     http://git.kernel.org/tip/2f63b9db7260beba3c19d66d6c11b0b78ea84a8c
Author:     Jan Beulich <JBeulich@suse.com>
AuthorDate: Mon, 1 Jun 2015 13:03:59 +0100
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 2 Jun 2015 10:10:09 +0200

x86/asm/entry/64: Fold identical code paths

retint_kernel doesn't require %rcx to be pointing to thread info
(anymore?), and the code on the two alternative paths is - not
really surprisingly - identical.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/556C664F020000780007FB64@mail.emea.novell.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/kernel/entry_64.S | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index b84cec5..4ad79e9 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -615,7 +615,7 @@ ret_from_intr:
 	testb	$3, CS(%rsp)
 	jz	retint_kernel
 	/* Interrupt came from user space */
-
+retint_user:
 	GET_THREAD_INFO(%rcx)
 	/*
 	 * %rcx: thread info. Interrupts off.
@@ -1194,15 +1194,9 @@ ENTRY(error_exit)
 	RESTORE_EXTRA_REGS
 	DISABLE_INTERRUPTS(CLBR_NONE)
 	TRACE_IRQS_OFF
-	GET_THREAD_INFO(%rcx)
 	testl %eax,%eax
 	jnz retint_kernel
-	LOCKDEP_SYS_EXIT_IRQ
-	movl TI_flags(%rcx),%edx
-	movl $_TIF_WORK_MASK,%edi
-	andl %edi,%edx
-	jnz retint_careful
-	jmp retint_swapgs
+	jmp retint_user
 END(error_exit)
 
 /* Runs on exception stack */