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authorRussell King <rmk+kernel@arm.linux.org.uk>2011-06-25 18:28:19 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2011-07-02 10:56:10 +0100
commitbc089602d206b2abc2d2e8e5324d90342cc0447b (patch)
tree6f5f062109d2756b92eff8545531fb5f12df3929 /arch/arm/kernel/entry-armv.S
parentdf295df6c391e322a06dea0d2bc3d22debd15fb9 (diff)
downloadlinux-bc089602d206b2abc2d2e8e5324d90342cc0447b.tar.gz
ARM: entry: instrument usr exception handlers with irqsoff tracing
As we no longer re-enable interrupts in these exception handlers, add the irqsoff tracing calls to them so that the kernel tracks the state more accurately. Note that these calls are conditional on IRQSOFF_TRACER: kernel ----------> user ---------> kernel ^ irqs enabled ^ irqs disabled No kernel code can run on the local CPU until we've re-entered the kernel through one of the exception handlers - and userspace can not take any locks etc. So, the kernel doesn't care about the IRQ mask state while userspace is running unless we're doing IRQ off latency tracing. So, we can (and do) avoid the overhead of updating the IRQ mask state on every kernel->user and user->kernel transition. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/kernel/entry-armv.S')
-rw-r--r--arch/arm/kernel/entry-armv.S17
1 files changed, 16 insertions, 1 deletions
diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S
index 920dd3d0795..f863ee79093 100644
--- a/arch/arm/kernel/entry-armv.S
+++ b/arch/arm/kernel/entry-armv.S
@@ -421,6 +421,11 @@ ENDPROC(__pabt_svc)
.align 5
__dabt_usr:
usr_entry
+
+#ifdef CONFIG_IRQSOFF_TRACER
+ bl trace_hardirqs_off
+#endif
+
kuser_cmpxchg_check
dabt_helper
@@ -433,12 +438,12 @@ ENDPROC(__dabt_usr)
.align 5
__irq_usr:
usr_entry
- kuser_cmpxchg_check
#ifdef CONFIG_IRQSOFF_TRACER
bl trace_hardirqs_off
#endif
+ kuser_cmpxchg_check
irq_handler
get_thread_info tsk
mov why, #0
@@ -451,6 +456,11 @@ ENDPROC(__irq_usr)
.align 5
__und_usr:
usr_entry
+
+#ifdef CONFIG_IRQSOFF_TRACER
+ bl trace_hardirqs_off
+#endif
+
mov r2, r4
mov r3, r5
@@ -669,6 +679,11 @@ ENDPROC(__und_usr_unknown)
.align 5
__pabt_usr:
usr_entry
+
+#ifdef CONFIG_IRQSOFF_TRACER
+ bl trace_hardirqs_off
+#endif
+
pabt_helper
mov r2, sp @ regs
bl do_PrefetchAbort @ call abort handler