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authorRalf Baechle <ralf@linux-mips.org>2007-03-29 23:42:42 +0100
committerRalf Baechle <ralf@linux-mips.org>2007-03-29 23:46:36 +0100
commit8a1e97ee2e025f116765c92409a3cf8f6cb07ad6 (patch)
treec3df538fce3f32b35b1b8355a9a411cb668e724e /include
parent6c9fde4bfff11b2fd93b4e518ae7ecb25a9244e4 (diff)
[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>
Diffstat (limited to 'include')
-rw-r--r--include/asm-mips/irqflags.h55
-rw-r--r--include/asm-mips/smtc_ipi.h16
2 files changed, 36 insertions, 35 deletions
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)
{
diff --git a/include/asm-mips/smtc_ipi.h b/include/asm-mips/smtc_ipi.h
index 360ea6d250c..a52a4a7a36e 100644
--- a/include/asm-mips/smtc_ipi.h
+++ b/include/asm-mips/smtc_ipi.h
@@ -65,12 +65,10 @@ static inline void smtc_ipi_nq(struct smtc_ipi_q *q, struct smtc_ipi *p)
spin_unlock_irqrestore(&q->lock, flags);
}
-static inline struct smtc_ipi *smtc_ipi_dq(struct smtc_ipi_q *q)
+static inline struct smtc_ipi *__smtc_ipi_dq(struct smtc_ipi_q *q)
{
struct smtc_ipi *p;
- long flags;
- spin_lock_irqsave(&q->lock, flags);
if (q->head == NULL)
p = NULL;
else {
@@ -81,7 +79,19 @@ static inline struct smtc_ipi *smtc_ipi_dq(struct smtc_ipi_q *q)
if (q->head == NULL)
q->tail = NULL;
}
+
+ return p;
+}
+
+static inline struct smtc_ipi *smtc_ipi_dq(struct smtc_ipi_q *q)
+{
+ unsigned long flags;
+ struct smtc_ipi *p;
+
+ spin_lock_irqsave(&q->lock, flags);
+ p = __smtc_ipi_dq(q);
spin_unlock_irqrestore(&q->lock, flags);
+
return p;
}