3.18-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit 433678bdc6ed39f053c55da96b51de5bf0aeebb1 ]
This patch fixes a problem with the initialization of the sysfs_show() routine for the RAPL PMU.
The current code was wrongly relying on the EVENT_ATTR_STR() macro which uses the events_sysfs_show() function in the x86 PMU code. That function itself was relying on the x86_pmu data structure. Yet RAPL and the core PMU (x86_pmu) have nothing to do with each other. They should therefore not interact with each other.
The x86_pmu structure is initialized at boot time based on the host CPU model. When the host CPU is not supported, the x86_pmu remains uninitialized and some of the callbacks it contains are NULL.
The false dependency with x86_pmu could potentially cause crashes in case the x86_pmu is not initialized while the RAPL PMU is. This may, for instance, be the case in virtualized environments.
This patch fixes the problem by using a private sysfs_show() routine for exporting the RAPL PMU events.
Signed-off-by: Stephane Eranian eranian@google.com Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Link: http://lkml.kernel.org/r/20150113225953.GA21525@thinkpad Cc: vincent.weaver@maine.edu Cc: jolsa@redhat.com Cc: Arnaldo Carvalho de Melo acme@kernel.org Cc: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- arch/x86/kernel/cpu/perf_event_intel_rapl.c | 44 +++++++++++++++------ 1 file changed, 32 insertions(+), 12 deletions(-)
diff --git a/arch/x86/kernel/cpu/perf_event_intel_rapl.c b/arch/x86/kernel/cpu/perf_event_intel_rapl.c index 611d821eac1a..040915c87cb6 100644 --- a/arch/x86/kernel/cpu/perf_event_intel_rapl.c +++ b/arch/x86/kernel/cpu/perf_event_intel_rapl.c @@ -103,6 +103,13 @@ static struct kobj_attribute format_attr_##_var = \
#define RAPL_CNTR_WIDTH 32 /* 32-bit rapl counters */
+#define RAPL_EVENT_ATTR_STR(_name, v, str) \ +static struct perf_pmu_events_attr event_attr_##v = { \ + .attr = __ATTR(_name, 0444, rapl_sysfs_show, NULL), \ + .id = 0, \ + .event_str = str, \ +}; + struct rapl_pmu { spinlock_t lock; int hw_unit; /* 1/2^hw_unit Joule */ @@ -383,23 +390,36 @@ static struct attribute_group rapl_pmu_attr_group = { .attrs = rapl_pmu_attrs, };
-EVENT_ATTR_STR(energy-cores, rapl_cores, "event=0x01"); -EVENT_ATTR_STR(energy-pkg , rapl_pkg, "event=0x02"); -EVENT_ATTR_STR(energy-ram , rapl_ram, "event=0x03"); -EVENT_ATTR_STR(energy-gpu , rapl_gpu, "event=0x04"); +static ssize_t rapl_sysfs_show(struct device *dev, + struct device_attribute *attr, + char *page) +{ + struct perf_pmu_events_attr *pmu_attr = \ + container_of(attr, struct perf_pmu_events_attr, attr); + + if (pmu_attr->event_str) + return sprintf(page, "%s", pmu_attr->event_str); + + return 0; +} + +RAPL_EVENT_ATTR_STR(energy-cores, rapl_cores, "event=0x01"); +RAPL_EVENT_ATTR_STR(energy-pkg , rapl_pkg, "event=0x02"); +RAPL_EVENT_ATTR_STR(energy-ram , rapl_ram, "event=0x03"); +RAPL_EVENT_ATTR_STR(energy-gpu , rapl_gpu, "event=0x04");
-EVENT_ATTR_STR(energy-cores.unit, rapl_cores_unit, "Joules"); -EVENT_ATTR_STR(energy-pkg.unit , rapl_pkg_unit, "Joules"); -EVENT_ATTR_STR(energy-ram.unit , rapl_ram_unit, "Joules"); -EVENT_ATTR_STR(energy-gpu.unit , rapl_gpu_unit, "Joules"); +RAPL_EVENT_ATTR_STR(energy-cores.unit, rapl_cores_unit, "Joules"); +RAPL_EVENT_ATTR_STR(energy-pkg.unit , rapl_pkg_unit, "Joules"); +RAPL_EVENT_ATTR_STR(energy-ram.unit , rapl_ram_unit, "Joules"); +RAPL_EVENT_ATTR_STR(energy-gpu.unit , rapl_gpu_unit, "Joules");
/* * we compute in 0.23 nJ increments regardless of MSR */ -EVENT_ATTR_STR(energy-cores.scale, rapl_cores_scale, "2.3283064365386962890625e-10"); -EVENT_ATTR_STR(energy-pkg.scale, rapl_pkg_scale, "2.3283064365386962890625e-10"); -EVENT_ATTR_STR(energy-ram.scale, rapl_ram_scale, "2.3283064365386962890625e-10"); -EVENT_ATTR_STR(energy-gpu.scale, rapl_gpu_scale, "2.3283064365386962890625e-10"); +RAPL_EVENT_ATTR_STR(energy-cores.scale, rapl_cores_scale, "2.3283064365386962890625e-10"); +RAPL_EVENT_ATTR_STR(energy-pkg.scale, rapl_pkg_scale, "2.3283064365386962890625e-10"); +RAPL_EVENT_ATTR_STR(energy-ram.scale, rapl_ram_scale, "2.3283064365386962890625e-10"); +RAPL_EVENT_ATTR_STR(energy-gpu.scale, rapl_gpu_scale, "2.3283064365386962890625e-10");
static struct attribute *rapl_events_srv_attr[] = { EVENT_PTR(rapl_cores),