mirror of https://gitee.com/openkylin/linux.git
[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>
This commit is contained in:
Ralf Baechle
parent
6c9fde4bff
commit
8a1e97ee2e
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@ -999,10 +999,17 @@ static void setup_cross_vpe_interrupts(unsigned int nvpe)
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/*
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* SMTC-specific hacks invoked from elsewhere in the kernel.
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*
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* smtc_ipi_replay is called from raw_local_irq_restore which is only ever
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* called with interrupts disabled. We do rely on interrupts being disabled
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* here because using spin_lock_irqsave()/spin_unlock_irqrestore() would
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* result in a recursive call to raw_local_irq_restore().
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*/
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void smtc_ipi_replay(void)
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static void __smtc_ipi_replay(void)
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{
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unsigned int cpu = smp_processor_id();
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/*
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* To the extent that we've ever turned interrupts off,
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* we may have accumulated deferred IPIs. This is subtle.
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@ -1017,17 +1024,30 @@ void smtc_ipi_replay(void)
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* is clear, and we'll handle it as a real pseudo-interrupt
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* and not a pseudo-pseudo interrupt.
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*/
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if (IPIQ[smp_processor_id()].depth > 0) {
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struct smtc_ipi *pipi;
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extern void self_ipi(struct smtc_ipi *);
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if (IPIQ[cpu].depth > 0) {
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while (1) {
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struct smtc_ipi_q *q = &IPIQ[cpu];
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struct smtc_ipi *pipi;
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extern void self_ipi(struct smtc_ipi *);
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spin_lock(&q->lock);
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pipi = __smtc_ipi_dq(q);
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spin_unlock(&q->lock);
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if (!pipi)
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break;
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while ((pipi = smtc_ipi_dq(&IPIQ[smp_processor_id()]))) {
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self_ipi(pipi);
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smtc_cpu_stats[smp_processor_id()].selfipis++;
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smtc_cpu_stats[cpu].selfipis++;
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}
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}
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}
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void smtc_ipi_replay(void)
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{
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raw_local_irq_disable();
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__smtc_ipi_replay();
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}
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EXPORT_SYMBOL(smtc_ipi_replay);
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void smtc_idle_loop_hook(void)
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@ -1132,7 +1152,13 @@ void smtc_idle_loop_hook(void)
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* is in use, there should never be any.
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*/
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#ifndef CONFIG_MIPS_MT_SMTC_INSTANT_REPLAY
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smtc_ipi_replay();
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{
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unsigned long flags;
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local_irq_save(flags);
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__smtc_ipi_replay();
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local_irq_restore(flags);
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}
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#endif /* CONFIG_MIPS_MT_SMTC_INSTANT_REPLAY */
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}
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@ -13,29 +13,9 @@
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#ifndef __ASSEMBLY__
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#include <linux/compiler.h>
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#include <asm/hazards.h>
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/*
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* CONFIG_MIPS_MT_SMTC_INSTANT_REPLAY does prompt replay of deferred IPIs,
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* at the cost of branch and call overhead on each local_irq_restore()
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*/
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#ifdef CONFIG_MIPS_MT_SMTC_INSTANT_REPLAY
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extern void smtc_ipi_replay(void);
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#define irq_restore_epilog(flags) \
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do { \
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if (!(flags & 0x0400)) \
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smtc_ipi_replay(); \
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} while (0)
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#else
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#define irq_restore_epilog(ignore) do { } while (0)
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#endif /* CONFIG_MIPS_MT_SMTC_INSTANT_REPLAY */
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__asm__ (
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" .macro raw_local_irq_enable \n"
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" .set push \n"
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@ -205,17 +185,28 @@ __asm__ (
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" .set pop \n"
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" .endm \n");
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#define raw_local_irq_restore(flags) \
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do { \
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unsigned long __tmp1; \
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\
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__asm__ __volatile__( \
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"raw_local_irq_restore\t%0" \
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: "=r" (__tmp1) \
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: "0" (flags) \
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: "memory"); \
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irq_restore_epilog(flags); \
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} while(0)
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extern void smtc_ipi_replay(void);
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static inline void raw_local_irq_restore(unsigned long flags)
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{
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unsigned long __tmp1;
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#ifdef CONFIG_MIPS_MT_SMTC_INSTANT_REPLAY
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/*
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* CONFIG_MIPS_MT_SMTC_INSTANT_REPLAY does prompt replay of deferred
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* IPIs, at the cost of branch and call overhead on each
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* local_irq_restore()
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*/
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if (unlikely(!(flags & 0x0400)))
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smtc_ipi_replay();
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#endif
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__asm__ __volatile__(
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"raw_local_irq_restore\t%0"
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: "=r" (__tmp1)
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: "0" (flags)
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: "memory");
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}
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static inline int raw_irqs_disabled_flags(unsigned long flags)
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{
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@ -65,12 +65,10 @@ static inline void smtc_ipi_nq(struct smtc_ipi_q *q, struct smtc_ipi *p)
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spin_unlock_irqrestore(&q->lock, flags);
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}
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static inline struct smtc_ipi *smtc_ipi_dq(struct smtc_ipi_q *q)
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static inline struct smtc_ipi *__smtc_ipi_dq(struct smtc_ipi_q *q)
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{
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struct smtc_ipi *p;
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long flags;
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spin_lock_irqsave(&q->lock, flags);
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if (q->head == NULL)
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p = NULL;
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else {
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@ -81,7 +79,19 @@ static inline struct smtc_ipi *smtc_ipi_dq(struct smtc_ipi_q *q)
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if (q->head == NULL)
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q->tail = NULL;
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}
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return p;
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}
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static inline struct smtc_ipi *smtc_ipi_dq(struct smtc_ipi_q *q)
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{
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unsigned long flags;
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struct smtc_ipi *p;
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spin_lock_irqsave(&q->lock, flags);
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p = __smtc_ipi_dq(q);
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spin_unlock_irqrestore(&q->lock, flags);
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return p;
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}
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