From ff967900c9d4740f6337c6456f111104267633cb Mon Sep 17 00:00:00 2001
From: Nicholas Piggin <npiggin@gmail.com>
Date: Sat, 21 Oct 2017 17:56:06 +1000
Subject: [PATCH] powerpc/64: Fix latency tracing for lazy irq replay
When returning from an exception to a soft-enabled context, pending
IRQs are replayed but IRQ tracing is not reset, so a number of them
can get chained together into the same IRQ-disabled trace.
Fix this by having __check_irq_replay re-set IRQ trace. This is
conceptually where we respond to the next interrupt, so it fits the
semantics of the IRQ tracer.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
arch/powerpc/kernel/irq.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 6a6995173f518..b7a84522e652c 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -143,6 +143,13 @@ notrace unsigned int __check_irq_replay(void)
*/
unsigned char happened = local_paca->irq_happened;
+ /*
+ * We are responding to the next interrupt, so interrupt-off
+ * latencies should be reset here.
+ */
+ trace_hardirqs_on();
+ trace_hardirqs_off();
+
if (happened & PACA_IRQ_HARD_DIS) {
/* Clear bit 0 which we wouldn't clear otherwise */
local_paca->irq_happened &= ~PACA_IRQ_HARD_DIS;
@@ -270,6 +277,7 @@ notrace void arch_local_irq_restore(unsigned long en)
#endif /* CONFIG_TRACE_IRQFLAGS */
set_soft_enabled(0);
+ trace_hardirqs_off();
/*
* Check if anything needs to be re-emitted. We haven't
@@ -279,6 +287,7 @@ notrace void arch_local_irq_restore(unsigned long en)
replay = __check_irq_replay();
/* We can soft-enable now */
+ trace_hardirqs_on();
set_soft_enabled(1);
/*
--
2.30.2