diff options
Diffstat (limited to 'arch/s390/kernel/perf_cpum_cf.c')
| -rw-r--r-- | arch/s390/kernel/perf_cpum_cf.c | 32 |
1 files changed, 26 insertions, 6 deletions
diff --git a/arch/s390/kernel/perf_cpum_cf.c b/arch/s390/kernel/perf_cpum_cf.c index 66d945d5589b..b2e46b8b881a 100644 --- a/arch/s390/kernel/perf_cpum_cf.c +++ b/arch/s390/kernel/perf_cpum_cf.c @@ -236,25 +236,45 @@ static void setup_pmc_cpu(void *flags) lcctl(0); } -/* Initialize the CPU-measurement facility */ -static int reserve_pmc_hardware(void) +/* Reserve/release functions for sharing perf hardware */ +static DEFINE_SPINLOCK(cpumcf_owner_lock); +static void *cpumcf_owner; + +/* Initialize the CPU-measurement counter facility */ +int __kernel_cpumcf_begin(void) { int flags = PMC_INIT; + int err = 0; + + spin_lock(&cpumcf_owner_lock); + if (cpumcf_owner) + err = -EBUSY; + else + cpumcf_owner = __builtin_return_address(0); + spin_unlock(&cpumcf_owner_lock); + if (err) + return err; on_each_cpu(setup_pmc_cpu, &flags, 1); irq_subclass_register(IRQ_SUBCLASS_MEASUREMENT_ALERT); return 0; } +EXPORT_SYMBOL(__kernel_cpumcf_begin); -/* Release the CPU-measurement facility */ -static void release_pmc_hardware(void) +/* Release the CPU-measurement counter facility */ +void __kernel_cpumcf_end(void) { int flags = PMC_RELEASE; on_each_cpu(setup_pmc_cpu, &flags, 1); irq_subclass_unregister(IRQ_SUBCLASS_MEASUREMENT_ALERT); + + spin_lock(&cpumcf_owner_lock); + cpumcf_owner = NULL; + spin_unlock(&cpumcf_owner_lock); } +EXPORT_SYMBOL(__kernel_cpumcf_end); /* Release the PMU if event is the last perf event */ static void hw_perf_event_destroy(struct perf_event *event) @@ -262,7 +282,7 @@ static void hw_perf_event_destroy(struct perf_event *event) if (!atomic_add_unless(&num_events, -1, 1)) { mutex_lock(&pmc_reserve_mutex); if (atomic_dec_return(&num_events) == 0) - release_pmc_hardware(); + __kernel_cpumcf_end(); mutex_unlock(&pmc_reserve_mutex); } } @@ -363,7 +383,7 @@ static int __hw_perf_event_init(struct perf_event *event) /* Initialize for using the CPU-measurement counter facility */ if (!atomic_inc_not_zero(&num_events)) { mutex_lock(&pmc_reserve_mutex); - if (atomic_read(&num_events) == 0 && reserve_pmc_hardware()) + if (atomic_read(&num_events) == 0 && __kernel_cpumcf_begin()) err = -EBUSY; else atomic_inc(&num_events); |