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Commit 58f8e9da authored by Hendrik Brueckner's avatar Hendrik Brueckner Committed by Martin Schwidefsky
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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: default avatarHendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 8d4bd0ed

arch/s390/kernel/perf_cpum_cf.c

+8 −4
Original line number Diff line number Diff line
@@ -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);