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ARM: perf: allow armpmu to implement mode exclusion 

Modern PMUs allow for mode exclusion, so we no longer wish to return
-EPERM if it is requested.

This patch provides a hook in the armpmu structure for implementing
mode exclusion. The hw_perf_event initialisation is slightly delayed so
that the backend code can update the structure if required.

Acked-by: Jamie Iles <jamie@jamieiles.com>
Reviewed-by: Jean Pihet <j-pihet@ti.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
This commit is contained in:
Will Deacon 2011-07-19 11:57:30 +01:00
parent ecf5a89321
commit 05d22fde3c
1 changed files with 26 additions and 20 deletions
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46
arch/arm/kernel/perf_event.c
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@ -75,6 +75,8 @@ struct arm_pmu {
void (*disable)(struct hw_perf_event *evt, int idx);
int (*get_event_idx)(struct cpu_hw_events *cpuc,
struct hw_perf_event *hwc);
int (*set_event_filter)(struct hw_perf_event *evt,
struct perf_event_attr *attr);
u32 (*read_counter)(int idx);
void (*write_counter)(int idx, u32 val);
void (*start)(void);
@ -477,6 +479,13 @@ hw_perf_event_destroy(struct perf_event *event)
}
}
static int
event_requires_mode_exclusion(struct perf_event_attr *attr)
{
return attr->exclude_idle || attr->exclude_user ||
attr->exclude_kernel || attr->exclude_hv;
}
static int
__hw_perf_event_init(struct perf_event *event)
{
@ -502,34 +511,31 @@ __hw_perf_event_init(struct perf_event *event)
}
/*
* Check whether we need to exclude the counter from certain modes.
* The ARM performance counters are on all of the time so if someone
* has asked us for some excludes then we have to fail.
* We don't assign an index until we actually place the event onto
* hardware. Use -1 to signify that we haven't decided where to put it
* yet. For SMP systems, each core has it's own PMU so we can't do any
* clever allocation or constraints checking at this point.
*/
if (event->attr.exclude_kernel || event->attr.exclude_user ||
event->attr.exclude_hv || event->attr.exclude_idle) {
hwc->idx = -1;
hwc->config_base = 0;
hwc->config = 0;
hwc->event_base = 0;
/*
* Check whether we need to exclude the counter from certain modes.
*/
if ((!armpmu->set_event_filter ||
armpmu->set_event_filter(hwc, &event->attr)) &&
event_requires_mode_exclusion(&event->attr)) {
pr_debug("ARM performance counters do not support "
"mode exclusion\n");
return -EPERM;
}
/*
* We don't assign an index until we actually place the event onto
* hardware. Use -1 to signify that we haven't decided where to put it
* yet. For SMP systems, each core has it's own PMU so we can't do any
* clever allocation or constraints checking at this point.
* Store the event encoding into the config_base field.
*/
hwc->idx = -1;
/*
* Store the event encoding into the config_base field. config and
* event_base are unused as the only 2 things we need to know are
* the event mapping and the counter to use. The counter to use is
* also the indx and the config_base is the event type.
*/
hwc->config_base = (unsigned long)mapping;
hwc->config = 0;
hwc->event_base = 0;
hwc->config_base |= (unsigned long)mapping;
if (!hwc->sample_period) {
hwc->sample_period = armpmu->max_period;