This is a note to let you know that I've just added the patch titled
powerpc/perf: Don't enable if we have zero events
to the 3.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
powerpc-perf-don-t-enable-if-we-have-zero-events.patch
and it can be found in the queue-3.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 4ea355b5368bde0574c12430df53334c4be3bdcf Mon Sep 17 00:00:00 2001
From: Michael Ellerman <michael@xxxxxxxxxxxxxx>
Date: Fri, 28 Jun 2013 18:15:14 +1000
Subject: powerpc/perf: Don't enable if we have zero events
From: Michael Ellerman <michael@xxxxxxxxxxxxxx>
commit 4ea355b5368bde0574c12430df53334c4be3bdcf upstream.
In power_pmu_enable() we still enable the PMU even if we have zero
events. This should have no effect but doesn't make much sense. Instead
just return after telling the hypervisor that we are not using the PMCs.
Signed-off-by: Michael Ellerman <michael@xxxxxxxxxxxxxx>
Signed-off-by: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/powerpc/perf/core-book3s.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
--- a/arch/powerpc/perf/core-book3s.c
+++ b/arch/powerpc/perf/core-book3s.c
@@ -926,6 +926,11 @@ static void power_pmu_enable(struct pmu
if (!cpuhw->disabled)
goto out;
+ if (cpuhw->n_events == 0) {
+ ppc_set_pmu_inuse(0);
+ goto out;
+ }
+
cpuhw->disabled = 0;
/*
@@ -937,8 +942,6 @@ static void power_pmu_enable(struct pmu
if (!cpuhw->n_added) {
mtspr(SPRN_MMCRA, cpuhw->mmcr[2] & ~MMCRA_SAMPLE_ENABLE);
mtspr(SPRN_MMCR1, cpuhw->mmcr[1]);
- if (cpuhw->n_events == 0)
- ppc_set_pmu_inuse(0);
goto out_enable;
}
Patches currently in stable-queue which might be from michael@xxxxxxxxxxxxxx are
queue-3.10/powerpc-perf-don-t-enable-if-we-have-zero-events.patch
queue-3.10/powerpc-rename-and-flesh-out-the-facility-unavailable-exception-handler.patch
queue-3.10/powerpc-perf-check-that-events-only-include-valid-bits-on-power8.patch
queue-3.10/powerpc-wire-up-the-hv-facility-unavailable-exception.patch
queue-3.10/powerpc-remove-kvmtest-from-relon-exception-handlers.patch
queue-3.10/powerpc-perf-rework-disable-logic-in-pmu_disable.patch
queue-3.10/powerpc-remove-unreachable-relocation-on-exception-handlers.patch
queue-3.10/powerpc-perf-freeze-pmc5-6-if-we-re-not-using-them.patch
queue-3.10/powerpc-perf-use-existing-out-label-in-power_pmu_enable.patch
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