Merge branch 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc
Pull another powerpc irq fix from Benjamin Herrenschmidt:
"It looks like my previous fix for the lazy irq masking problem wasn't
quite enough. There was another problem related to performance
monitor interrupts acting as NMIs leaving the flags in an incorrect
state. Here's a fix that finally seems to make perf solid again."
* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc:
powerpc/irq: Fix another case of lazy IRQ state getting out of sync
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index fc60150..ef2074c 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -588,23 +588,19 @@
fast_exc_return_irq:
restore:
/*
- * This is the main kernel exit path, we first check if we
- * have to change our interrupt state.
+ * This is the main kernel exit path. First we check if we
+ * are about to re-enable interrupts
*/
ld r5,SOFTE(r1)
lbz r6,PACASOFTIRQEN(r13)
- cmpwi cr1,r5,0
- cmpw cr0,r5,r6
- beq cr0,4f
+ cmpwi cr0,r5,0
+ beq restore_irq_off
- /* We do, handle disable first, which is easy */
- bne cr1,3f;
- li r0,0
- stb r0,PACASOFTIRQEN(r13);
- TRACE_DISABLE_INTS
- b 4f
+ /* We are enabling, were we already enabled ? Yes, just return */
+ cmpwi cr0,r6,1
+ beq cr0,do_restore
-3: /*
+ /*
* We are about to soft-enable interrupts (we are hard disabled
* at this point). We check if there's anything that needs to
* be replayed first.
@@ -626,7 +622,7 @@
/*
* Final return path. BookE is handled in a different file
*/
-4:
+do_restore:
#ifdef CONFIG_PPC_BOOK3E
b .exception_return_book3e
#else
@@ -700,6 +696,25 @@
#endif /* CONFIG_PPC_BOOK3E */
/*
+ * We are returning to a context with interrupts soft disabled.
+ *
+ * However, we may also about to hard enable, so we need to
+ * make sure that in this case, we also clear PACA_IRQ_HARD_DIS
+ * or that bit can get out of sync and bad things will happen
+ */
+restore_irq_off:
+ ld r3,_MSR(r1)
+ lbz r7,PACAIRQHAPPENED(r13)
+ andi. r0,r3,MSR_EE
+ beq 1f
+ rlwinm r7,r7,0,~PACA_IRQ_HARD_DIS
+ stb r7,PACAIRQHAPPENED(r13)
+1: li r0,0
+ stb r0,PACASOFTIRQEN(r13);
+ TRACE_DISABLE_INTS
+ b do_restore
+
+ /*
* Something did happen, check if a re-emit is needed
* (this also clears paca->irq_happened)
*/
@@ -748,6 +763,9 @@
#endif /* CONFIG_PPC_BOOK3E */
1: b .ret_from_except /* What else to do here ? */
+
+
+3:
do_work:
#ifdef CONFIG_PREEMPT
andi. r0,r3,MSR_PR /* Returning to user mode? */
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index c6c6f3b..641da9e 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -229,6 +229,19 @@
*/
if (unlikely(irq_happened != PACA_IRQ_HARD_DIS))
__hard_irq_disable();
+#ifdef CONFIG_TRACE_IRQFLAG
+ else {
+ /*
+ * We should already be hard disabled here. We had bugs
+ * where that wasn't the case so let's dbl check it and
+ * warn if we are wrong. Only do that when IRQ tracing
+ * is enabled as mfmsr() can be costly.
+ */
+ if (WARN_ON(mfmsr() & MSR_EE))
+ __hard_irq_disable();
+ }
+#endif /* CONFIG_TRACE_IRQFLAG */
+
set_soft_enabled(0);
/*