Commit-ID: 9f7ff8931e3c5ddc8535476971ec9501e9555c05
Gitweb: http://git.kernel.org/tip/9f7ff8931e3c5ddc8535476971ec9501e9555c05
Author: Stephane Eranian <eranian@xxxxxxxxxx>
AuthorDate: Wed, 23 Apr 2014 19:04:19 +0200
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Thu, 24 Apr 2014 08:12:41 +0200
perf/x86: Fix RAPL rdmsrl_safe() usage
This patch fixes a bug introduced by:
24223657806a ("perf/x86/intel: Use rdmsrl_safe() when initializing RAPL PMU")
The rdmsrl_safe() function returns 0 on success.
The current code was failing to detect the RAPL PMU
on real hardware (missing /sys/devices/power) because
the return value of rdmsrl_safe() was misinterpreted.
Signed-off-by: Stephane Eranian <eranian@xxxxxxxxxx>
Acked-by: Borislav Petkov <bp@xxxxxxx>
Acked-by: Venkatesh Srinivas <venkateshs@xxxxxxxxxx>
Cc: peterz@xxxxxxxxxxxxx
Cc: zheng.z.yan@xxxxxxxxx
Link: http://lkml.kernel.org/r/20140423170418.GA12767@quad
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/kernel/cpu/perf_event_intel_rapl.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kernel/cpu/perf_event_intel_rapl.c b/arch/x86/kernel/cpu/perf_event_intel_rapl.c
index 7c87424..619f769 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_rapl.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_rapl.c
@@ -543,7 +543,8 @@ static int rapl_cpu_prepare(int cpu)
if (phys_id < 0)
return -1;
- if (!rdmsrl_safe(MSR_RAPL_POWER_UNIT, &msr_rapl_power_unit_bits))
+ /* protect rdmsrl() to handle virtualization */
+ if (rdmsrl_safe(MSR_RAPL_POWER_UNIT, &msr_rapl_power_unit_bits))
return -1;
pmu = kzalloc_node(sizeof(*pmu), GFP_KERNEL, cpu_to_node(cpu));
--
To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
|