From d0427fe2982e2f4f644b936fe39636916b69fee1 Mon Sep 17 00:00:00 2001
From: Todd Android Poynor <toddpoynor@google.com>
Date: Thu, 23 Dec 2010 01:52:44 +0100
Subject: [PATCH 12/65] ARM: 6540/1: Stop irqsoff trace on return to user

If the irqsoff tracer is in use, stop tracing the interrupt disable
interval when returning to userspace.  Tracing userspace execution time
as interrupts disabled time is not helpful for kernel performance
analysis purposes.  Only do so if the irqsoff tracer is enabled, to
avoid overhead for lockdep, which doesn't care.

Signed-off-by: Todd Poynor <toddpoynor@google.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
---
 arch/arm/kernel/entry-common.S |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index 8bfa987..80bf8cd 100644
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -29,6 +29,9 @@ ret_fast_syscall:
 	ldr	r1, [tsk, #TI_FLAGS]
 	tst	r1, #_TIF_WORK_MASK
 	bne	fast_work_pending
+#if defined(CONFIG_IRQSOFF_TRACER)
+	asm_trace_hardirqs_on
+#endif
 
 	/* perform architecture specific actions before user return */
 	arch_ret_to_user r1, lr
@@ -65,6 +68,9 @@ ret_slow_syscall:
 	tst	r1, #_TIF_WORK_MASK
 	bne	work_pending
 no_work_pending:
+#if defined(CONFIG_IRQSOFF_TRACER)
+	asm_trace_hardirqs_on
+#endif
 	/* perform architecture specific actions before user return */
 	arch_ret_to_user r1, lr
 
-- 
1.6.6.1

