From 8a1e97ee2e025f116765c92409a3cf8f6cb07ad6 Mon Sep 17 00:00:00 2001
From: Ralf Baechle <ralf@linux-mips.org>
Date: Thu, 29 Mar 2007 23:42:42 +0100
Subject: [MIPS] SMTC: Fix recursion in instant IPI replay code.

local_irq_restore -> raw_local_irq_restore -> irq_restore_epilog ->
	smtc_ipi_replay -> smtc_ipi_dq -> spin_unlock_irqrestore ->
	_spin_unlock_irqrestore -> local_irq_restore

The recursion does abort when there is no more IPI queued for a CPU, so
this isn't usually fatal which is why we got away with this for so long
until this was discovered by code inspection.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
---
 include/asm-mips/irqflags.h | 55 +++++++++++++++++++--------------------------
 1 file changed, 23 insertions(+), 32 deletions(-)

(limited to 'include/asm-mips/irqflags.h')

diff --git a/include/asm-mips/irqflags.h b/include/asm-mips/irqflags.h
index af3b07dfad4..e459fa05db8 100644
--- a/include/asm-mips/irqflags.h
+++ b/include/asm-mips/irqflags.h
@@ -13,29 +13,9 @@
 
 #ifndef __ASSEMBLY__
 
+#include <linux/compiler.h>
 #include <asm/hazards.h>
 
-/*
- * CONFIG_MIPS_MT_SMTC_INSTANT_REPLAY does prompt replay of deferred IPIs,
- * at the cost of branch and call overhead on each local_irq_restore()
- */
-
-#ifdef CONFIG_MIPS_MT_SMTC_INSTANT_REPLAY
-
-extern void smtc_ipi_replay(void);
-
-#define irq_restore_epilog(flags)				\
-do {								\
-	if (!(flags & 0x0400))					\
-		smtc_ipi_replay();				\
-} while (0)
-
-#else
-
-#define irq_restore_epilog(ignore) do { } while (0)
-
-#endif /* CONFIG_MIPS_MT_SMTC_INSTANT_REPLAY */
-
 __asm__ (
 	"	.macro	raw_local_irq_enable				\n"
 	"	.set	push						\n"
@@ -205,17 +185,28 @@ __asm__ (
 	"	.set	pop						\n"
 	"	.endm							\n");
 
-#define raw_local_irq_restore(flags)					\
-do {									\
-	unsigned long __tmp1;						\
-									\
-	__asm__ __volatile__(						\
-		"raw_local_irq_restore\t%0"				\
-		: "=r" (__tmp1)						\
-		: "0" (flags)						\
-		: "memory");						\
-	irq_restore_epilog(flags);					\
-} while(0)
+extern void smtc_ipi_replay(void);
+
+static inline void raw_local_irq_restore(unsigned long flags)
+{
+	unsigned long __tmp1;
+
+#ifdef CONFIG_MIPS_MT_SMTC_INSTANT_REPLAY
+	/*
+	 * CONFIG_MIPS_MT_SMTC_INSTANT_REPLAY does prompt replay of deferred
+	 * IPIs, at the cost of branch and call overhead on each
+	 * local_irq_restore()
+	 */
+	if (unlikely(!(flags & 0x0400)))
+		smtc_ipi_replay();
+#endif
+
+	__asm__ __volatile__(
+		"raw_local_irq_restore\t%0"
+		: "=r" (__tmp1)
+		: "0" (flags)
+		: "memory");
+}
 
 static inline int raw_irqs_disabled_flags(unsigned long flags)
 {
-- 
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