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authorHendrik Brueckner <brueckner@linux.vnet.ibm.com>2015-09-07 10:52:42 +0200
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2015-09-17 13:43:42 +0200
commit58f8e9da33eb0104f5bee3e8b3ca44e1583c78b9 (patch)
treed889d71b48c2f548740cdefa0a37c9410a14f915 /arch/s390
parent8d4bd0ed0439dfc780aab801a085961925ed6838 (diff)
downloadlinux-58f8e9da33eb0104f5bee3e8b3ca44e1583c78b9.tar.gz
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>
Diffstat (limited to 'arch/s390')
-rw-r--r--arch/s390/kernel/perf_cpum_cf.c12
1 files changed, 8 insertions, 4 deletions
diff --git a/arch/s390/kernel/perf_cpum_cf.c b/arch/s390/kernel/perf_cpum_cf.c
index 56fdad479115..a9563409c36e 100644
--- a/arch/s390/kernel/perf_cpum_cf.c
+++ b/arch/s390/kernel/perf_cpum_cf.c
@@ -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);