diff options
Diffstat (limited to 'arch/s390/kernel/perf_cpum_cf_common.c')
| -rw-r--r-- | arch/s390/kernel/perf_cpum_cf_common.c | 201 |
1 files changed, 201 insertions, 0 deletions
diff --git a/arch/s390/kernel/perf_cpum_cf_common.c b/arch/s390/kernel/perf_cpum_cf_common.c new file mode 100644 index 000000000..3bced89ca --- /dev/null +++ b/arch/s390/kernel/perf_cpum_cf_common.c @@ -0,0 +1,201 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * CPU-Measurement Counter Facility Support - Common Layer + * + * Copyright IBM Corp. 2019 + * Author(s): Hendrik Brueckner <brueckner@linux.ibm.com> + */ +#define KMSG_COMPONENT "cpum_cf_common" +#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt + +#include <linux/kernel.h> +#include <linux/kernel_stat.h> +#include <linux/percpu.h> +#include <linux/notifier.h> +#include <linux/init.h> +#include <linux/export.h> +#include <asm/ctl_reg.h> +#include <asm/irq.h> +#include <asm/cpu_mcf.h> + +/* Per-CPU event structure for the counter facility */ +DEFINE_PER_CPU(struct cpu_cf_events, cpu_cf_events) = { + .ctr_set = { + [CPUMF_CTR_SET_BASIC] = ATOMIC_INIT(0), + [CPUMF_CTR_SET_USER] = ATOMIC_INIT(0), + [CPUMF_CTR_SET_CRYPTO] = ATOMIC_INIT(0), + [CPUMF_CTR_SET_EXT] = ATOMIC_INIT(0), + [CPUMF_CTR_SET_MT_DIAG] = ATOMIC_INIT(0), + }, + .alert = ATOMIC64_INIT(0), + .state = 0, + .flags = 0, + .txn_flags = 0, +}; +/* Indicator whether the CPU-Measurement Counter Facility Support is ready */ +static bool cpum_cf_initalized; + +/* CPU-measurement alerts for the counter facility */ +static void cpumf_measurement_alert(struct ext_code ext_code, + unsigned int alert, unsigned long unused) +{ + struct cpu_cf_events *cpuhw; + + if (!(alert & CPU_MF_INT_CF_MASK)) + return; + + inc_irq_stat(IRQEXT_CMC); + cpuhw = this_cpu_ptr(&cpu_cf_events); + + /* Measurement alerts are shared and might happen when the PMU + * is not reserved. Ignore these alerts in this case. */ + if (!(cpuhw->flags & PMU_F_RESERVED)) + return; + + /* counter authorization change alert */ + if (alert & CPU_MF_INT_CF_CACA) + qctri(&cpuhw->info); + + /* loss of counter data alert */ + if (alert & CPU_MF_INT_CF_LCDA) + pr_err("CPU[%i] Counter data was lost\n", smp_processor_id()); + + /* loss of MT counter data alert */ + if (alert & CPU_MF_INT_CF_MTDA) + pr_warn("CPU[%i] MT counter data was lost\n", + smp_processor_id()); + + /* store alert for special handling by in-kernel users */ + atomic64_or(alert, &cpuhw->alert); +} + +#define PMC_INIT 0 +#define PMC_RELEASE 1 +static void cpum_cf_setup_cpu(void *flags) +{ + struct cpu_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_events); + + switch (*((int *) flags)) { + case PMC_INIT: + memset(&cpuhw->info, 0, sizeof(cpuhw->info)); + qctri(&cpuhw->info); + cpuhw->flags |= PMU_F_RESERVED; + break; + + case PMC_RELEASE: + cpuhw->flags &= ~PMU_F_RESERVED; + break; + } + + /* Disable CPU counter sets */ + lcctl(0); +} + +bool kernel_cpumcf_avail(void) +{ + return cpum_cf_initalized; +} +EXPORT_SYMBOL(kernel_cpumcf_avail); + + +/* 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(cpum_cf_setup_cpu, &flags, 1); + irq_subclass_register(IRQ_SUBCLASS_MEASUREMENT_ALERT); + + return 0; +} +EXPORT_SYMBOL(__kernel_cpumcf_begin); + +/* Obtain the CPU-measurement alerts for the counter facility */ +unsigned long kernel_cpumcf_alert(int clear) +{ + struct cpu_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_events); + unsigned long alert; + + alert = atomic64_read(&cpuhw->alert); + if (clear) + atomic64_set(&cpuhw->alert, 0); + + return alert; +} +EXPORT_SYMBOL(kernel_cpumcf_alert); + +/* Release the CPU-measurement counter facility */ +void __kernel_cpumcf_end(void) +{ + int flags = PMC_RELEASE; + + on_each_cpu(cpum_cf_setup_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); + +static int cpum_cf_setup(unsigned int cpu, int flags) +{ + local_irq_disable(); + cpum_cf_setup_cpu(&flags); + local_irq_enable(); + return 0; +} + +static int cpum_cf_online_cpu(unsigned int cpu) +{ + return cpum_cf_setup(cpu, PMC_INIT); +} + +static int cpum_cf_offline_cpu(unsigned int cpu) +{ + return cpum_cf_setup(cpu, PMC_RELEASE); +} + +static int __init cpum_cf_init(void) +{ + int rc; + + if (!cpum_cf_avail()) + return -ENODEV; + + /* clear bit 15 of cr0 to unauthorize problem-state to + * extract measurement counters */ + ctl_clear_bit(0, 48); + + /* register handler for measurement-alert interruptions */ + rc = register_external_irq(EXT_IRQ_MEASURE_ALERT, + cpumf_measurement_alert); + if (rc) { + pr_err("Registering for CPU-measurement alerts " + "failed with rc=%i\n", rc); + return rc; + } + + rc = cpuhp_setup_state(CPUHP_AP_PERF_S390_CF_ONLINE, + "perf/s390/cf:online", + cpum_cf_online_cpu, cpum_cf_offline_cpu); + if (!rc) + cpum_cf_initalized = true; + + return rc; +} +early_initcall(cpum_cf_init); |