diff options
| author | Paul Mackerras <paulus@samba.org> | 2009-04-09 14:42:56 +1000 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-04-09 07:56:08 +0200 |
| commit | ca8f2d7f019a8547f39ddb9ed0144932f12807f2 (patch) | |
| tree | 6bf7693de5751a305e4233dba288e603de83ff47 /arch | |
| parent | 6c0b324435ff49fb3c68fe808a93853d81c7fb97 (diff) | |
perf_counter: powerpc: add nmi_enter/nmi_exit calls
Impact: fix potential deadlocks on powerpc
Now that the core is using in_nmi() (added in e30e08f6, "perf_counter:
fix NMI race in task clock"), we need the powerpc perf_counter_interrupt
to call nmi_enter() and nmi_exit() in those cases where the interrupt
happens when interrupts are soft-disabled.
If interrupts were soft-enabled, we can treat it as a regular interrupt
and do irq_enter/irq_exit around the whole routine. This lets us get rid
of the test_perf_counter_pending() call at the end of
perf_counter_interrupt, thus simplifying things a little.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <18909.31952.873098.336615@cargo.ozlabs.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/powerpc/kernel/perf_counter.c | 31 |
1 files changed, 17 insertions, 14 deletions
diff --git a/arch/powerpc/kernel/perf_counter.c b/arch/powerpc/kernel/perf_counter.c index c9d019f1907..bd76d0fa2c3 100644 --- a/arch/powerpc/kernel/perf_counter.c +++ b/arch/powerpc/kernel/perf_counter.c @@ -714,7 +714,7 @@ hw_perf_counter_init(struct perf_counter *counter) * here so there is no possibility of being interrupted. */ static void record_and_restart(struct perf_counter *counter, long val, - struct pt_regs *regs) + struct pt_regs *regs, int nmi) { s64 prev, delta, left; int record = 0; @@ -749,7 +749,7 @@ static void record_and_restart(struct perf_counter *counter, long val, * Finally record data if requested. */ if (record) - perf_counter_overflow(counter, 1, regs, 0); + perf_counter_overflow(counter, nmi, regs, 0); } /* @@ -762,6 +762,17 @@ static void perf_counter_interrupt(struct pt_regs *regs) struct perf_counter *counter; long val; int found = 0; + int nmi; + + /* + * If interrupts were soft-disabled when this PMU interrupt + * occurred, treat it as an NMI. + */ + nmi = !regs->softe; + if (nmi) + nmi_enter(); + else + irq_enter(); for (i = 0; i < cpuhw->n_counters; ++i) { counter = cpuhw->counter[i]; @@ -769,7 +780,7 @@ static void perf_counter_interrupt(struct pt_regs *regs) if ((int)val < 0) { /* counter has overflowed */ found = 1; - record_and_restart(counter, val, regs); + record_and_restart(counter, val, regs, nmi); } } @@ -796,18 +807,10 @@ static void perf_counter_interrupt(struct pt_regs *regs) */ mtspr(SPRN_MMCR0, cpuhw->mmcr[0]); - /* - * If we need a wakeup, check whether interrupts were soft-enabled - * when we took the interrupt. If they were, we can wake stuff up - * immediately; otherwise we'll have do the wakeup when interrupts - * get soft-enabled. - */ - if (test_perf_counter_pending() && regs->softe) { - irq_enter(); - clear_perf_counter_pending(); - perf_counter_do_pending(); + if (nmi) + nmi_exit(); + else irq_exit(); - } } void hw_perf_counter_setup(int cpu) |