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| author | Paul Mackerras <paulus@samba.org> | 2009-01-09 16:52:19 +1100 |
|---|---|---|
| committer | Paul Mackerras <paulus@samba.org> | 2009-01-09 19:48:17 +1100 |
| commit | 93a6d3ce6962044fe9badf528fed46b455d58292 (patch) | |
| tree | e3941058ddb4117b4598b8d94fb218cfeb9e2fa8 /arch/powerpc/kernel/entry_64.S | |
| parent | d662ed26734473d4cb5f3d78cebfec8f9126e97c (diff) | |
| download | blackbird-op-linux-93a6d3ce6962044fe9badf528fed46b455d58292.tar.gz blackbird-op-linux-93a6d3ce6962044fe9badf528fed46b455d58292.zip | |
powerpc: Provide a way to defer perf counter work until interrupts are enabled
Because 64-bit powerpc uses lazy (soft) interrupt disabling, it is
possible for a performance monitor exception to come in when the
kernel thinks interrupts are disabled (i.e. when they are
soft-disabled but hard-enabled). In such a situation the performance
monitor exception handler might have some processing to do (such as
process wakeups) which can't be done in what is effectively an NMI
handler.
This provides a way to defer that work until interrupts get enabled,
either in raw_local_irq_restore() or by returning from an interrupt
handler to code that had interrupts enabled. We have a per-processor
flag that indicates that there is work pending to do when interrupts
subsequently get re-enabled. This flag is checked in the interrupt
return path and in raw_local_irq_restore(), and if it is set,
perf_counter_do_pending() is called to do the pending work.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'arch/powerpc/kernel/entry_64.S')
| -rw-r--r-- | arch/powerpc/kernel/entry_64.S | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S index 383ed6eb0085..f30b4e553c53 100644 --- a/arch/powerpc/kernel/entry_64.S +++ b/arch/powerpc/kernel/entry_64.S @@ -526,6 +526,15 @@ ALT_FW_FTR_SECTION_END_IFCLR(FW_FEATURE_ISERIES) 2: TRACE_AND_RESTORE_IRQ(r5); +#ifdef CONFIG_PERF_COUNTERS + /* check paca->perf_counter_pending if we're enabling ints */ + lbz r3,PACAPERFPEND(r13) + and. r3,r3,r5 + beq 27f + bl .perf_counter_do_pending +27: +#endif /* CONFIG_PERF_COUNTERS */ + /* extract EE bit and use it to restore paca->hard_enabled */ ld r3,_MSR(r1) rldicl r4,r3,49,63 /* r0 = (r3 >> 15) & 1 */ |
