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s390/cpum_cf: Corrected return code for unauthorized counter sets 

Previously, the cpum_cf PMU returned -EPERM if a counter is requested and
the counter set to which the counter belongs is not authorized.  According
to the perf_event_open() system call manual, an error code of EPERM indicates
an unsupported exclude setting or CAP_SYS_ADMIN is missing.

Use ENOENT to indicate that particular counters are not available when the
counter set which contains the counter is not authorized.  For generic events,
this might trigger a fall back, for example, to a software event.

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Hendrik Brueckner 2015-09-07 10:52:42 +02:00 committed by Martin Schwidefsky
parent 8d4bd0ed04
commit 58f8e9da33
1 changed files with 8 additions and 4 deletions
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12
arch/s390/kernel/perf_cpum_cf.c
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@ -157,10 +157,14 @@ static int validate_ctr_auth(const struct hw_perf_event *hwc)
cpuhw = &get_cpu_var(cpu_hw_events);
/* check authorization for cpu counter sets */
/* Check authorization for cpu counter sets.
* If the particular CPU counter set is not authorized,
* return with -ENOENT in order to fall back to other
* PMUs that might suffice the event request.
*/
ctrs_state = cpumf_state_ctl[hwc->config_base];
if (!(ctrs_state & cpuhw->info.auth_ctl))
err = -EPERM;
err = -ENOENT;
put_cpu_var(cpu_hw_events);
return err;
@ -536,7 +540,7 @@ static int cpumf_pmu_add(struct perf_event *event, int flags)
*/
if (!(cpuhw->flags & PERF_EVENT_TXN))
if (validate_ctr_auth(&event->hw))
return -EPERM;
return -ENOENT;
ctr_set_enable(&cpuhw->state, event->hw.config_base);
event->hw.state = PERF_HES_UPTODATE | PERF_HES_STOPPED;
@ -611,7 +615,7 @@ static int cpumf_pmu_commit_txn(struct pmu *pmu)
state = cpuhw->state & ~((1 << CPUMF_LCCTL_ENABLE_SHIFT) - 1);
state >>= CPUMF_LCCTL_ENABLE_SHIFT;
if ((state & cpuhw->info.auth_ctl) != state)
return -EPERM;
return -ENOENT;
cpuhw->flags &= ~PERF_EVENT_TXN;
perf_pmu_enable(pmu);