kernel-ark/include/asm-mips/smtc_ipi.h
Ralf Baechle 8a1e97ee2e [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>
2007-03-29 23:46:36 +01:00

128 lines
2.2 KiB
C

/*
* Definitions used in MIPS MT SMTC "Interprocessor Interrupt" code.
*/
#ifndef __ASM_SMTC_IPI_H
#define __ASM_SMTC_IPI_H
#include <linux/spinlock.h>
//#define SMTC_IPI_DEBUG
#ifdef SMTC_IPI_DEBUG
#include <asm/mipsregs.h>
#include <asm/mipsmtregs.h>
#endif /* SMTC_IPI_DEBUG */
/*
* An IPI "message"
*/
struct smtc_ipi {
struct smtc_ipi *flink;
int type;
void *arg;
int dest;
#ifdef SMTC_IPI_DEBUG
int sender;
long stamp;
#endif /* SMTC_IPI_DEBUG */
};
/*
* Defined IPI Types
*/
#define LINUX_SMP_IPI 1
#define SMTC_CLOCK_TICK 2
/*
* A queue of IPI messages
*/
struct smtc_ipi_q {
struct smtc_ipi *head;
spinlock_t lock;
struct smtc_ipi *tail;
int depth;
};
static inline void smtc_ipi_nq(struct smtc_ipi_q *q, struct smtc_ipi *p)
{
long flags;
spin_lock_irqsave(&q->lock, flags);
if (q->head == NULL)
q->head = q->tail = p;
else
q->tail->flink = p;
p->flink = NULL;
q->tail = p;
q->depth++;
#ifdef SMTC_IPI_DEBUG
p->sender = read_c0_tcbind();
p->stamp = read_c0_count();
#endif /* SMTC_IPI_DEBUG */
spin_unlock_irqrestore(&q->lock, flags);
}
static inline struct smtc_ipi *__smtc_ipi_dq(struct smtc_ipi_q *q)
{
struct smtc_ipi *p;
if (q->head == NULL)
p = NULL;
else {
p = q->head;
q->head = q->head->flink;
q->depth--;
/* Arguably unnecessary, but leaves queue cleaner */
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;
}
static inline void smtc_ipi_req(struct smtc_ipi_q *q, struct smtc_ipi *p)
{
long flags;
spin_lock_irqsave(&q->lock, flags);
if (q->head == NULL) {
q->head = q->tail = p;
p->flink = NULL;
} else {
p->flink = q->head;
q->head = p;
}
q->depth++;
spin_unlock_irqrestore(&q->lock, flags);
}
static inline int smtc_ipi_qdepth(struct smtc_ipi_q *q)
{
long flags;
int retval;
spin_lock_irqsave(&q->lock, flags);
retval = q->depth;
spin_unlock_irqrestore(&q->lock, flags);
return retval;
}
extern void smtc_send_ipi(int cpu, int type, unsigned int action);
#endif /* __ASM_SMTC_IPI_H */