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 8bfa98757cd2f3fc9ef128011944a55fa7838ffd..80bf8cd88d7c522c319354c75b13d5484b9ede96 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