diff options
Diffstat (limited to 'arch/x86/kernel/cpu/perf_event.c')
| -rw-r--r-- | arch/x86/kernel/cpu/perf_event.c | 76 |
1 files changed, 58 insertions, 18 deletions
diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c index 143e5f5dc855..b71a7f86d68a 100644 --- a/arch/x86/kernel/cpu/perf_event.c +++ b/arch/x86/kernel/cpu/perf_event.c @@ -31,6 +31,8 @@ #include <asm/nmi.h> #include <asm/smp.h> #include <asm/alternative.h> +#include <asm/mmu_context.h> +#include <asm/tlbflush.h> #include <asm/timer.h> #include <asm/desc.h> #include <asm/ldt.h> @@ -43,6 +45,8 @@ DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events) = { .enabled = 1, }; +struct static_key rdpmc_always_available = STATIC_KEY_INIT_FALSE; + u64 __read_mostly hw_cache_event_ids [PERF_COUNT_HW_CACHE_MAX] [PERF_COUNT_HW_CACHE_OP_MAX] @@ -1327,8 +1331,6 @@ x86_pmu_notifier(struct notifier_block *self, unsigned long action, void *hcpu) break; case CPU_STARTING: - if (x86_pmu.attr_rdpmc) - set_in_cr4(X86_CR4_PCE); if (x86_pmu.cpu_starting) x86_pmu.cpu_starting(cpu); break; @@ -1804,14 +1806,44 @@ static int x86_pmu_event_init(struct perf_event *event) event->destroy(event); } + if (ACCESS_ONCE(x86_pmu.attr_rdpmc)) + event->hw.flags |= PERF_X86_EVENT_RDPMC_ALLOWED; + return err; } +static void refresh_pce(void *ignored) +{ + if (current->mm) + load_mm_cr4(current->mm); +} + +static void x86_pmu_event_mapped(struct perf_event *event) +{ + if (!(event->hw.flags & PERF_X86_EVENT_RDPMC_ALLOWED)) + return; + + if (atomic_inc_return(¤t->mm->context.perf_rdpmc_allowed) == 1) + on_each_cpu_mask(mm_cpumask(current->mm), refresh_pce, NULL, 1); +} + +static void x86_pmu_event_unmapped(struct perf_event *event) +{ + if (!current->mm) + return; + + if (!(event->hw.flags & PERF_X86_EVENT_RDPMC_ALLOWED)) + return; + + if (atomic_dec_and_test(¤t->mm->context.perf_rdpmc_allowed)) + on_each_cpu_mask(mm_cpumask(current->mm), refresh_pce, NULL, 1); +} + static int x86_pmu_event_idx(struct perf_event *event) { int idx = event->hw.idx; - if (!x86_pmu.attr_rdpmc) + if (!(event->hw.flags & PERF_X86_EVENT_RDPMC_ALLOWED)) return 0; if (x86_pmu.num_counters_fixed && idx >= INTEL_PMC_IDX_FIXED) { @@ -1829,16 +1861,6 @@ static ssize_t get_attr_rdpmc(struct device *cdev, return snprintf(buf, 40, "%d\n", x86_pmu.attr_rdpmc); } -static void change_rdpmc(void *info) -{ - bool enable = !!(unsigned long)info; - - if (enable) - set_in_cr4(X86_CR4_PCE); - else - clear_in_cr4(X86_CR4_PCE); -} - static ssize_t set_attr_rdpmc(struct device *cdev, struct device_attribute *attr, const char *buf, size_t count) @@ -1850,14 +1872,27 @@ static ssize_t set_attr_rdpmc(struct device *cdev, if (ret) return ret; + if (val > 2) + return -EINVAL; + if (x86_pmu.attr_rdpmc_broken) return -ENOTSUPP; - if (!!val != !!x86_pmu.attr_rdpmc) { - x86_pmu.attr_rdpmc = !!val; - on_each_cpu(change_rdpmc, (void *)val, 1); + if ((val == 2) != (x86_pmu.attr_rdpmc == 2)) { + /* + * Changing into or out of always available, aka + * perf-event-bypassing mode. This path is extremely slow, + * but only root can trigger it, so it's okay. + */ + if (val == 2) + static_key_slow_inc(&rdpmc_always_available); + else + static_key_slow_dec(&rdpmc_always_available); + on_each_cpu(refresh_pce, NULL, 1); } + x86_pmu.attr_rdpmc = val; + return count; } @@ -1900,6 +1935,9 @@ static struct pmu pmu = { .event_init = x86_pmu_event_init, + .event_mapped = x86_pmu_event_mapped, + .event_unmapped = x86_pmu_event_unmapped, + .add = x86_pmu_add, .del = x86_pmu_del, .start = x86_pmu_start, @@ -1914,13 +1952,15 @@ static struct pmu pmu = { .flush_branch_stack = x86_pmu_flush_branch_stack, }; -void arch_perf_update_userpage(struct perf_event_mmap_page *userpg, u64 now) +void arch_perf_update_userpage(struct perf_event *event, + struct perf_event_mmap_page *userpg, u64 now) { struct cyc2ns_data *data; userpg->cap_user_time = 0; userpg->cap_user_time_zero = 0; - userpg->cap_user_rdpmc = x86_pmu.attr_rdpmc; + userpg->cap_user_rdpmc = + !!(event->hw.flags & PERF_X86_EVENT_RDPMC_ALLOWED); userpg->pmc_width = x86_pmu.cntval_bits; if (!sched_clock_stable()) |