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[MIPS] SMTC: Fix recursion in instant IPI replay code.

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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>
This commit is contained in:
Ralf Baechle
2007-03-29 23:42:42 +01:00
parent 6c9fde4bff
commit 8a1e97ee2e
3 changed files with 69 additions and 42 deletions
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55
include/asm-mips/irqflags.h
View File

@ -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)
{