powerpc/irq: Fix bug with new lazy IRQ handling code
We had a case where we could turn on hard interrupts while
leaving the PACA_IRQ_HARD_DIS bit set in the PACA. This can
in turn cause a BUG_ON() to hit in __check_irq_replay() due
to interrupt state getting out of sync.
The assembly code was also way too convoluted. Instead, we
now leave it to the C code to do the right thing which ends
up being smaller and more readable.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index f8a7a1a..fc60150 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -767,16 +767,6 @@
SOFT_DISABLE_INTS(r3,r4)
1: bl .preempt_schedule_irq
- /* Hard-disable interrupts again (and update PACA) */
-#ifdef CONFIG_PPC_BOOK3E
- wrteei 0
-#else
- ld r10,PACAKMSR(r13) /* Get kernel MSR without EE */
- mtmsrd r10,1
-#endif /* CONFIG_PPC_BOOK3E */
- li r0,PACA_IRQ_HARD_DIS
- stb r0,PACAIRQHAPPENED(r13)
-
/* Re-test flags and eventually loop */
clrrdi r9,r1,THREAD_SHIFT
ld r4,TI_FLAGS(r9)
@@ -787,14 +777,6 @@
user_work:
#endif /* CONFIG_PREEMPT */
- /* Enable interrupts */
-#ifdef CONFIG_PPC_BOOK3E
- wrteei 1
-#else
- ori r10,r10,MSR_EE
- mtmsrd r10,1
-#endif /* CONFIG_PPC_BOOK3E */
-
andi. r0,r4,_TIF_NEED_RESCHED
beq 1f
bl .restore_interrupts
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 43eb74f..c6c6f3b 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -260,11 +260,17 @@
* if they are currently disabled. This is typically called before
* schedule() or do_signal() when returning to userspace. We do it
* in C to avoid the burden of dealing with lockdep etc...
+ *
+ * NOTE: This is called with interrupts hard disabled but not marked
+ * as such in paca->irq_happened, so we need to resync this.
*/
void restore_interrupts(void)
{
- if (irqs_disabled())
+ if (irqs_disabled()) {
+ local_paca->irq_happened |= PACA_IRQ_HARD_DIS;
local_irq_enable();
+ } else
+ __hard_irq_enable();
}
#endif /* CONFIG_PPC64 */