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>

diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index 8bfa987..80bf8cd 100644 (file)
--- 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