Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
+44
-13
+31
-13
arch/powerpc/kernel/entry_64.S
+31
-13
arch/powerpc/kernel/entry_64.S
···
588
588
fast_exc_return_irq:
589
589
restore:
590
590
/*
591
-
* This is the main kernel exit path, we first check if we
592
-
* have to change our interrupt state.
591
+
* This is the main kernel exit path. First we check if we
592
+
* are about to re-enable interrupts
593
593
*/
594
594
ld r5,SOFTE(r1)
595
595
lbz r6,PACASOFTIRQEN(r13)
596
-
cmpwi cr1,r5,0
597
-
cmpw cr0,r5,r6
598
-
beq cr0,4f
596
+
cmpwi cr0,r5,0
597
+
beq restore_irq_off
599
598
600
-
/* We do, handle disable first, which is easy */
601
-
bne cr1,3f;
602
-
li r0,0
603
-
stb r0,PACASOFTIRQEN(r13);
604
-
TRACE_DISABLE_INTS
605
-
b 4f
599
+
/* We are enabling, were we already enabled ? Yes, just return */
600
+
cmpwi cr0,r6,1
601
+
beq cr0,do_restore
606
602
607
-
3: /*
603
+
/*
608
604
* We are about to soft-enable interrupts (we are hard disabled
609
605
* at this point). We check if there's anything that needs to
610
606
* be replayed first.
···
622
626
/*
623
627
* Final return path. BookE is handled in a different file
624
628
*/
625
-
4:
629
+
do_restore:
626
630
#ifdef CONFIG_PPC_BOOK3E
627
631
b .exception_return_book3e
628
632
#else
···
696
700
#endif /* CONFIG_PPC_BOOK3E */
697
701
698
702
/*
703
+
* We are returning to a context with interrupts soft disabled.
704
+
*
705
+
* However, we may also about to hard enable, so we need to
706
+
* make sure that in this case, we also clear PACA_IRQ_HARD_DIS
707
+
* or that bit can get out of sync and bad things will happen
708
+
*/
709
+
restore_irq_off:
710
+
ld r3,_MSR(r1)
711
+
lbz r7,PACAIRQHAPPENED(r13)
712
+
andi. r0,r3,MSR_EE
713
+
beq 1f
714
+
rlwinm r7,r7,0,~PACA_IRQ_HARD_DIS
715
+
stb r7,PACAIRQHAPPENED(r13)
716
+
1: li r0,0
717
+
stb r0,PACASOFTIRQEN(r13);
718
+
TRACE_DISABLE_INTS
719
+
b do_restore
720
+
721
+
/*
699
722
* Something did happen, check if a re-emit is needed
700
723
* (this also clears paca->irq_happened)
701
724
*/
···
763
748
#endif /* CONFIG_PPC_BOOK3E */
764
749
1: b .ret_from_except /* What else to do here ? */
765
750
751
+
752
+
753
+
3:
766
754
do_work:
767
755
#ifdef CONFIG_PREEMPT
768
756
andi. r0,r3,MSR_PR /* Returning to user mode? */
+13
arch/powerpc/kernel/irq.c
+13
arch/powerpc/kernel/irq.c
···
229
229
*/
230
230
if (unlikely(irq_happened != PACA_IRQ_HARD_DIS))
231
231
__hard_irq_disable();
232
+
#ifdef CONFIG_TRACE_IRQFLAG
233
+
else {
234
+
/*
235
+
* We should already be hard disabled here. We had bugs
236
+
* where that wasn't the case so let's dbl check it and
237
+
* warn if we are wrong. Only do that when IRQ tracing
238
+
* is enabled as mfmsr() can be costly.
239
+
*/
240
+
if (WARN_ON(mfmsr() & MSR_EE))
241
+
__hard_irq_disable();
242
+
}
243
+
#endif /* CONFIG_TRACE_IRQFLAG */
244
+
232
245
set_soft_enabled(0);
233
246
234
247
/*