hollalinux
/
linux-sg2042
mirror of https://github.com/sophgo/linux-riscv.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

metag: perf: fixes for interrupting perf counters 

The overflow handler needs to read modify write when re-enabling the
counter so as not to change the counter value as it may have been
changed to ready the next interrupt on overflow. Similarly for
interrupting counters metag_pmu_enable_counter needs to leave the
counter value unchanged rather than resetting it to zero.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
This commit is contained in:
James Hogan 2013-02-27 16:16:38 +00:00
parent c43ca04b5e
commit db59932f62
1 changed files with 15 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
arch/metag/kernel/perf/perf_event.c
View File

@ -643,13 +643,15 @@ static void metag_pmu_enable_counter(struct hw_perf_event *event, int idx)
config = tmp >> 4;
}
/*
* Enabled counters start from 0. Early cores clear the count on
* write but newer cores don't, so we make sure that the count is
* set to 0.
*/
tmp = ((config & 0xf) << 28) |
((1 << 24) << cpu_2_hwthread_id[get_cpu()]);
if (metag_pmu->max_period)
/*
* Cores supporting overflow interrupts may have had the counter
* set to a specific value that needs preserving.
*/
tmp |= metag_in32(PERF_COUNT(idx)) & 0x00ffffff;
metag_out32(tmp, PERF_COUNT(idx));
unlock:
raw_spin_unlock_irqrestore(&events->pmu_lock, flags);
@ -764,10 +766,16 @@ static irqreturn_t metag_pmu_counter_overflow(int irq, void *dev)
/*
* Enable the counter again once core overflow processing has
* completed.
* completed. Note the counter value may have been modified while it was
* inactive to set it up ready for the next interrupt.
*/
if (!perf_event_overflow(event, &sampledata, regs))
if (!perf_event_overflow(event, &sampledata, regs)) {
__global_lock2(flags);
counter = (counter & 0xff000000) |
(metag_in32(PERF_COUNT(idx)) & 0x00ffffff);
metag_out32(counter, PERF_COUNT(idx));
__global_unlock2(flags);
}
return IRQ_HANDLED;
}