diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c index 6ae20c4217af69..81cc9f0e718aba 100644 --- a/arch/arm64/kernel/perf_event.c +++ b/arch/arm64/kernel/perf_event.c @@ -285,6 +285,7 @@ static const struct attribute_group armv8_pmuv3_events_attr_group = { PMU_FORMAT_ATTR(event, "config:0-15"); PMU_FORMAT_ATTR(long, "config1:0"); +PMU_FORMAT_ATTR(rdpmc, "config1:1"); static int sysctl_perf_user_access __read_mostly; @@ -293,9 +294,15 @@ static inline bool armv8pmu_event_is_64bit(struct perf_event *event) return event->attr.config1 & 0x1; } +static inline bool armv8pmu_event_want_user_access(struct perf_event *event) +{ + return event->attr.config1 & 0x2; +} + static struct attribute *armv8_pmuv3_format_attrs[] = { &format_attr_event.attr, &format_attr_long.attr, + &format_attr_rdpmc.attr, NULL, }; @@ -364,7 +371,7 @@ static const struct attribute_group armv8_pmuv3_caps_attr_group = { */ #define ARMV8_IDX_CYCLE_COUNTER 0 #define ARMV8_IDX_COUNTER0 1 - +#define ARMV8_IDX_CYCLE_COUNTER_USER 32 /* * We unconditionally enable ARMv8.5-PMU long event counter support @@ -376,18 +383,22 @@ static bool armv8pmu_has_long_event(struct arm_pmu *cpu_pmu) return (cpu_pmu->pmuver >= ID_AA64DFR0_PMUVER_8_5); } +static inline bool armv8pmu_event_has_user_read(struct perf_event *event) +{ + return event->hw.flags & PERF_EVENT_FLAG_USER_READ_CNT; +} + /* * We must chain two programmable counters for 64 bit events, * except when we have allocated the 64bit cycle counter (for CPU - * cycles event). This must be called only when the event has - * a counter allocated. + * cycles event) or when user space counter access is enabled. */ static inline bool armv8pmu_event_is_chained(struct perf_event *event) { int idx = event->hw.idx; struct arm_pmu *cpu_pmu = to_arm_pmu(event->pmu); - return !WARN_ON(idx < 0) && + return !armv8pmu_event_has_user_read(event) && armv8pmu_event_is_64bit(event) && !armv8pmu_has_long_event(cpu_pmu) && (idx != ARMV8_IDX_CYCLE_COUNTER); @@ -720,6 +731,28 @@ static inline u32 armv8pmu_getreset_flags(void) return value; } +static void armv8pmu_disable_user_access(void) +{ + write_sysreg(0, pmuserenr_el0); +} + +static void armv8pmu_enable_user_access(struct arm_pmu *cpu_pmu) +{ + int i; + struct pmu_hw_events *cpuc = this_cpu_ptr(cpu_pmu->hw_events); + + /* Clear any unused counters to avoid leaking their contents */ + for_each_clear_bit(i, cpuc->used_mask, cpu_pmu->num_events) { + if (i == ARMV8_IDX_CYCLE_COUNTER) + write_sysreg(0, pmccntr_el0); + else + armv8pmu_write_evcntr(i, 0); + } + + write_sysreg(0, pmuserenr_el0); + write_sysreg(ARMV8_PMU_USERENR_ER | ARMV8_PMU_USERENR_CR, pmuserenr_el0); +} + static void armv8pmu_enable_event(struct perf_event *event) { /* @@ -763,6 +796,14 @@ static void armv8pmu_disable_event(struct perf_event *event) static void armv8pmu_start(struct arm_pmu *cpu_pmu) { + struct perf_event_context *task_ctx = + this_cpu_ptr(cpu_pmu->pmu.pmu_cpu_context)->task_ctx; + + if (sysctl_perf_user_access && task_ctx && task_ctx->nr_user) + armv8pmu_enable_user_access(cpu_pmu); + else + armv8pmu_disable_user_access(); + /* Enable all counters */ armv8pmu_pmcr_write(armv8pmu_pmcr_read() | ARMV8_PMU_PMCR_E); } @@ -880,13 +921,16 @@ static int armv8pmu_get_event_idx(struct pmu_hw_events *cpuc, if (evtype == ARMV8_PMUV3_PERFCTR_CPU_CYCLES) { if (!test_and_set_bit(ARMV8_IDX_CYCLE_COUNTER, cpuc->used_mask)) return ARMV8_IDX_CYCLE_COUNTER; + else if (armv8pmu_event_is_64bit(event) && + armv8pmu_event_want_user_access(event) && + !armv8pmu_has_long_event(cpu_pmu)) + return -EAGAIN; } /* * Otherwise use events counters */ - if (armv8pmu_event_is_64bit(event) && - !armv8pmu_has_long_event(cpu_pmu)) + if (armv8pmu_event_is_chained(event)) return armv8pmu_get_chain_idx(cpuc, cpu_pmu); else return armv8pmu_get_single_idx(cpuc, cpu_pmu); @@ -902,6 +946,22 @@ static void armv8pmu_clear_event_idx(struct pmu_hw_events *cpuc, clear_bit(idx - 1, cpuc->used_mask); } +static int armv8pmu_user_event_idx(struct perf_event *event) +{ + if (!sysctl_perf_user_access || !armv8pmu_event_has_user_read(event)) + return 0; + + /* + * We remap the cycle counter index to 32 to + * match the offset applied to the rest of + * the counter indices. + */ + if (event->hw.idx == ARMV8_IDX_CYCLE_COUNTER) + return ARMV8_IDX_CYCLE_COUNTER_USER; + + return event->hw.idx; +} + /* * Add an event filter to a given event. */ @@ -998,6 +1058,25 @@ static int __armv8_pmuv3_map_event(struct perf_event *event, if (armv8pmu_event_is_64bit(event)) event->hw.flags |= ARMPMU_EVT_64BIT; + /* + * User events must be allocated into a single counter, and so + * must not be chained. + * + * Most 64-bit events require long counter support, but 64-bit + * CPU_CYCLES events can be placed into the dedicated cycle + * counter when this is free. + */ + if (armv8pmu_event_want_user_access(event)) { + if (!(event->attach_state & PERF_ATTACH_TASK)) + return -EINVAL; + if (armv8pmu_event_is_64bit(event) && + (hw_event_id != ARMV8_PMUV3_PERFCTR_CPU_CYCLES) && + !armv8pmu_has_long_event(armpmu)) + return -EOPNOTSUPP; + + event->hw.flags |= PERF_EVENT_FLAG_USER_READ_CNT; + } + /* Only expose micro/arch events supported by this PMU */ if ((hw_event_id > 0) && (hw_event_id < ARMV8_PMUV3_MAX_COMMON_EVENTS) && test_bit(hw_event_id, armpmu->pmceid_bitmap)) { @@ -1106,13 +1185,29 @@ static int armv8pmu_probe_pmu(struct arm_pmu *cpu_pmu) return probe.present ? 0 : -ENODEV; } +static void armv8pmu_disable_user_access_ipi(void *unused) +{ + armv8pmu_disable_user_access(); +} + +static int armv8pmu_proc_user_access_handler(struct ctl_table *table, int write, + void *buffer, size_t *lenp, loff_t *ppos) +{ + int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); + if (ret || !write || sysctl_perf_user_access) + return ret; + + on_each_cpu(armv8pmu_disable_user_access_ipi, NULL, 1); + return 0; +} + static struct ctl_table armv8_pmu_sysctl_table[] = { { .procname = "perf_user_access", .data = &sysctl_perf_user_access, .maxlen = sizeof(unsigned int), .mode = 0644, - .proc_handler = proc_dointvec_minmax, + .proc_handler = armv8pmu_proc_user_access_handler, .extra1 = SYSCTL_ZERO, .extra2 = SYSCTL_ONE, }, @@ -1142,6 +1237,8 @@ static int armv8_pmu_init(struct arm_pmu *cpu_pmu, char *name, cpu_pmu->set_event_filter = armv8pmu_set_event_filter; cpu_pmu->filter_match = armv8pmu_filter_match; + cpu_pmu->pmu.event_idx = armv8pmu_user_event_idx; + cpu_pmu->name = name; cpu_pmu->map_event = map_event; cpu_pmu->attr_groups[ARMPMU_ATTR_GROUP_EVENTS] = events ? @@ -1318,6 +1415,14 @@ void arch_perf_update_userpage(struct perf_event *event, userpg->cap_user_time = 0; userpg->cap_user_time_zero = 0; userpg->cap_user_time_short = 0; + userpg->cap_user_rdpmc = armv8pmu_event_has_user_read(event); + + if (userpg->cap_user_rdpmc) { + if (event->hw.flags & ARMPMU_EVT_64BIT) + userpg->pmc_width = 64; + else + userpg->pmc_width = 32; + } do { rd = sched_clock_read_begin(&seq);