diff options
| author | Michael Ellerman | 2014-03-14 06:00:29 +0100 |
|---|---|---|
| committer | Benjamin Herrenschmidt | 2014-03-23 23:48:25 +0100 |
| commit | c2e37a2626a7471875f3a6452b99dfd3809972b9 (patch) | |
| tree | 60c994235d65095308288c8ee3543b1e027d2c92 /arch/powerpc/perf/power8-pmu.c | |
| parent | powerpc: Add a cpu feature CPU_FTR_PMAO_BUG (diff) | |
| download | kernel-qcow2-linux-c2e37a2626a7471875f3a6452b99dfd3809972b9.tar.gz kernel-qcow2-linux-c2e37a2626a7471875f3a6452b99dfd3809972b9.tar.xz kernel-qcow2-linux-c2e37a2626a7471875f3a6452b99dfd3809972b9.zip | |
powerpc/perf: Add lost exception workaround
Some power8 revisions have a hardware bug where we can lose a PMU
exception, this commit adds a workaround to detect the bad condition and
rectify the situation.
See the comment in the commit for a full description.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/perf/power8-pmu.c')
| -rw-r--r-- | arch/powerpc/perf/power8-pmu.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/powerpc/perf/power8-pmu.c b/arch/powerpc/perf/power8-pmu.c index 96cee20dcd34..64f04cfabd23 100644 --- a/arch/powerpc/perf/power8-pmu.c +++ b/arch/powerpc/perf/power8-pmu.c @@ -10,6 +10,8 @@ * 2 of the License, or (at your option) any later version. */ +#define pr_fmt(fmt) "power8-pmu: " fmt + #include <linux/kernel.h> #include <linux/perf_event.h> #include <asm/firmware.h> @@ -774,6 +776,9 @@ static int __init init_power8_pmu(void) /* Tell userspace that EBB is supported */ cur_cpu_spec->cpu_user_features2 |= PPC_FEATURE2_EBB; + if (cpu_has_feature(CPU_FTR_PMAO_BUG)) + pr_info("PMAO restore workaround active.\n"); + return 0; } early_initcall(init_power8_pmu); |