linux/arch/powerpc/include/asm/hw_irq.h
Paul Mackerras 0fe1ac48be powerpc/perf_event: Fix oops due to perf_event_do_pending call
Anton Blanchard found that large POWER systems would occasionally
crash in the exception exit path when profiling with perf_events.
The symptom was that an interrupt would occur late in the exit path
when the MSR[RI] (recoverable interrupt) bit was clear.  Interrupts
should be hard-disabled at this point but they were enabled.  Because
the interrupt was not recoverable the system panicked.

The reason is that the exception exit path was calling
perf_event_do_pending after hard-disabling interrupts, and
perf_event_do_pending will re-enable interrupts.

The simplest and cleanest fix for this is to use the same mechanism
that 32-bit powerpc does, namely to cause a self-IPI by setting the
decrementer to 1.  This means we can remove the tests in the exception
exit path and raw_local_irq_restore.

This also makes sure that the call to perf_event_do_pending from
timer_interrupt() happens within irq_enter/irq_exit.  (Note that
calling perf_event_do_pending from timer_interrupt does not mean that
there is a possible 1/HZ latency; setting the decrementer to 1 ensures
that the timer interrupt will happen immediately, i.e. within one
timebase tick, which is a few nanoseconds or 10s of nanoseconds.)

Signed-off-by: Paul Mackerras <paulus@samba.org>
Cc: stable@kernel.org
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2010-05-12 14:34:00 +10:00

135 lines
3.1 KiB
C

/*
* Copyright (C) 1999 Cort Dougan <cort@cs.nmt.edu>
*/
#ifndef _ASM_POWERPC_HW_IRQ_H
#define _ASM_POWERPC_HW_IRQ_H
#ifdef __KERNEL__
#include <linux/errno.h>
#include <linux/compiler.h>
#include <asm/ptrace.h>
#include <asm/processor.h>
extern void timer_interrupt(struct pt_regs *);
#ifdef CONFIG_PPC64
#include <asm/paca.h>
static inline unsigned long local_get_flags(void)
{
unsigned long flags;
__asm__ __volatile__("lbz %0,%1(13)"
: "=r" (flags)
: "i" (offsetof(struct paca_struct, soft_enabled)));
return flags;
}
static inline unsigned long raw_local_irq_disable(void)
{
unsigned long flags, zero;
__asm__ __volatile__("li %1,0; lbz %0,%2(13); stb %1,%2(13)"
: "=r" (flags), "=&r" (zero)
: "i" (offsetof(struct paca_struct, soft_enabled))
: "memory");
return flags;
}
extern void raw_local_irq_restore(unsigned long);
extern void iseries_handle_interrupts(void);
#define raw_local_irq_enable() raw_local_irq_restore(1)
#define raw_local_save_flags(flags) ((flags) = local_get_flags())
#define raw_local_irq_save(flags) ((flags) = raw_local_irq_disable())
#define raw_irqs_disabled() (local_get_flags() == 0)
#define raw_irqs_disabled_flags(flags) ((flags) == 0)
#ifdef CONFIG_PPC_BOOK3E
#define __hard_irq_enable() __asm__ __volatile__("wrteei 1": : :"memory");
#define __hard_irq_disable() __asm__ __volatile__("wrteei 0": : :"memory");
#else
#define __hard_irq_enable() __mtmsrd(mfmsr() | MSR_EE, 1)
#define __hard_irq_disable() __mtmsrd(mfmsr() & ~MSR_EE, 1)
#endif
#define hard_irq_disable() \
do { \
__hard_irq_disable(); \
get_paca()->soft_enabled = 0; \
get_paca()->hard_enabled = 0; \
} while(0)
#else
#if defined(CONFIG_BOOKE)
#define SET_MSR_EE(x) mtmsr(x)
#define raw_local_irq_restore(flags) __asm__ __volatile__("wrtee %0" : : "r" (flags) : "memory")
#else
#define SET_MSR_EE(x) mtmsr(x)
#define raw_local_irq_restore(flags) mtmsr(flags)
#endif
static inline void raw_local_irq_disable(void)
{
#ifdef CONFIG_BOOKE
__asm__ __volatile__("wrteei 0": : :"memory");
#else
unsigned long msr;
msr = mfmsr();
SET_MSR_EE(msr & ~MSR_EE);
#endif
}
static inline void raw_local_irq_enable(void)
{
#ifdef CONFIG_BOOKE
__asm__ __volatile__("wrteei 1": : :"memory");
#else
unsigned long msr;
msr = mfmsr();
SET_MSR_EE(msr | MSR_EE);
#endif
}
static inline void raw_local_irq_save_ptr(unsigned long *flags)
{
unsigned long msr;
msr = mfmsr();
*flags = msr;
#ifdef CONFIG_BOOKE
__asm__ __volatile__("wrteei 0": : :"memory");
#else
SET_MSR_EE(msr & ~MSR_EE);
#endif
}
#define raw_local_save_flags(flags) ((flags) = mfmsr())
#define raw_local_irq_save(flags) raw_local_irq_save_ptr(&flags)
#define raw_irqs_disabled() ((mfmsr() & MSR_EE) == 0)
#define raw_irqs_disabled_flags(flags) (((flags) & MSR_EE) == 0)
#define hard_irq_disable() raw_local_irq_disable()
static inline int irqs_disabled_flags(unsigned long flags)
{
return (flags & MSR_EE) == 0;
}
#endif /* CONFIG_PPC64 */
/*
* interrupt-retrigger: should we handle this via lost interrupts and IPIs
* or should we not care like we do now ? --BenH.
*/
struct irq_chip;
#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_HW_IRQ_H */