arm: Don't disable interrupts during WFE fixup
Disabling interrupts during the Krait WFE fixup can result
in deadlock if a thread tries to acquire a spinlock that is
released from an interrupt context. Instead of disabling
interrupts, modify the interrupt handler to reset the fixup
condition to put the processor into a safe state in the
event that the interrupt came in during the fixup window.
CRs-Fixed: 383670
Change-Id: Id504f46d6f840dc32ca11ed2f813003143e60f2d
Signed-off-by: Stepan Moskovchenko <stepanm@codeaurora.org>
diff --git a/arch/arm/include/asm/spinlock.h b/arch/arm/include/asm/spinlock.h
index 94aa75e..bc81696 100644
--- a/arch/arm/include/asm/spinlock.h
+++ b/arch/arm/include/asm/spinlock.h
@@ -37,9 +37,11 @@
#endif
/*
- * The fixup involves disabling interrupts during execution of the WFE
- * instruction. This could potentially lead to deadlock if a thread is trying
- * to acquire a spinlock which is being released from an interrupt context.
+ * The fixup involves disabling FIQs during execution of the WFE instruction.
+ * This could potentially lead to deadlock if a thread is trying to acquire a
+ * spinlock which is being released from an FIQ. This should not be a problem
+ * because FIQs are handled by the secure environment and do not directly
+ * manipulate spinlocks.
*/
#ifdef CONFIG_MSM_KRAIT_WFE_FIXUP
#define WFE_SAFE(fixup, tmp) \
@@ -47,7 +49,7 @@
" cmp " fixup ", #0\n" \
" wfeeq\n" \
" beq 10f\n" \
-" cpsid if\n" \
+" cpsid f\n" \
" mrc p15, 7, " fixup ", c15, c0, 5\n" \
" bic " fixup ", " fixup ", #0x10000\n" \
" mcr p15, 7, " fixup ", c15, c0, 5\n" \