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perf/rapl: Fix sysfs_show() initialization for RAPL PMU

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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>
This commit is contained in:
Stephane Eranian 2015-01-13 23:59:53 +01:00 committed by Ingo Molnar
parent f800c25b7a
commit 433678bdc6
1 changed files with 32 additions and 12 deletions
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44
arch/x86/kernel/cpu/perf_event_intel_rapl.c
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@ -103,6 +103,13 @@ static struct kobj_attribute format_attr_##_var = \
#define RAPL_CNTR_WIDTH 32 /* 32-bit rapl counters */ #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 { struct rapl_pmu {
spinlock_t lock; spinlock_t lock;
int hw_unit; /* 1/2^hw_unit Joule */ int hw_unit; /* 1/2^hw_unit Joule */
@ -379,23 +386,36 @@ static struct attribute_group rapl_pmu_attr_group = {
.attrs = rapl_pmu_attrs, .attrs = rapl_pmu_attrs,
}; };
EVENT_ATTR_STR(energy-cores, rapl_cores, "event=0x01"); static ssize_t rapl_sysfs_show(struct device *dev,
EVENT_ATTR_STR(energy-pkg , rapl_pkg, "event=0x02"); struct device_attribute *attr,
EVENT_ATTR_STR(energy-ram , rapl_ram, "event=0x03"); char *page)
EVENT_ATTR_STR(energy-gpu , rapl_gpu, "event=0x04"); {
struct perf_pmu_events_attr *pmu_attr = \
container_of(attr, struct perf_pmu_events_attr, attr);
EVENT_ATTR_STR(energy-cores.unit, rapl_cores_unit, "Joules"); if (pmu_attr->event_str)
EVENT_ATTR_STR(energy-pkg.unit , rapl_pkg_unit, "Joules"); return sprintf(page, "%s", pmu_attr->event_str);
EVENT_ATTR_STR(energy-ram.unit , rapl_ram_unit, "Joules");
EVENT_ATTR_STR(energy-gpu.unit , rapl_gpu_unit, "Joules"); 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");
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 * we compute in 0.23 nJ increments regardless of MSR
*/ */
EVENT_ATTR_STR(energy-cores.scale, rapl_cores_scale, "2.3283064365386962890625e-10"); RAPL_EVENT_ATTR_STR(energy-cores.scale, rapl_cores_scale, "2.3283064365386962890625e-10");
EVENT_ATTR_STR(energy-pkg.scale, rapl_pkg_scale, "2.3283064365386962890625e-10"); RAPL_EVENT_ATTR_STR(energy-pkg.scale, rapl_pkg_scale, "2.3283064365386962890625e-10");
EVENT_ATTR_STR(energy-ram.scale, rapl_ram_scale, "2.3283064365386962890625e-10"); RAPL_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-gpu.scale, rapl_gpu_scale, "2.3283064365386962890625e-10");
static struct attribute *rapl_events_srv_attr[] = { static struct attribute *rapl_events_srv_attr[] = {
EVENT_PTR(rapl_cores), EVENT_PTR(rapl_cores),