ARM: 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 purely for lockdep, which doesn't
care.

Change-Id: I74cde7dd0c4c3a783af34e76bd4efc1f85315abe
Signed-off-by: Todd Poynor <toddpoynor@google.com>

diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index 7885722bdf4eff7115137ac46444c8d176f05b57..c4a7050d878e295e618f9ff486ca39a1b230c587 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