diff options
| author | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2012-05-10 16:12:38 +0000 |
|---|---|---|
| committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2012-05-12 09:40:41 +1000 |
| commit | 7c0482e3d055e5de056d3c693b821e39205b99ae (patch) | |
| tree | ad8d3ff6965d675c6bd255c5665deab7fba5df9f /arch/powerpc/kernel/entry_64.S | |
| parent | 4e25651b70b8d6ded7229ead8181619e121b648d (diff) | |
powerpc/irq: Fix another case of lazy IRQ state getting out of sync
So we have another case of paca->irq_happened getting out of
sync with the HW irq state. This can happen when a perfmon
interrupt occurs while soft disabled, as it will return to a
soft disabled but hard enabled context while leaving a stale
PACA_IRQ_HARD_DIS flag set.
This patch fixes it, and also adds a test for the condition
of those flags being out of sync in arch_local_irq_restore()
when CONFIG_TRACE_IRQFLAGS is enabled.
This helps catching those gremlins faster (and so far I
can't seem see any anymore, so that's good news).
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/kernel/entry_64.S')
| -rw-r--r-- | arch/powerpc/kernel/entry_64.S | 44 |
1 files changed, 31 insertions, 13 deletions
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S index fc6015027a8..ef2074c3e90 100644 --- a/arch/powerpc/kernel/entry_64.S +++ b/arch/powerpc/kernel/entry_64.S @@ -588,23 +588,19 @@ _GLOBAL(ret_from_except_lite) 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 @@ restore_no_replay: /* * 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 @@ fast_exception_return: #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 @@ restore_check_irq_replay: #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? */ |