diff options
| -rw-r--r-- | Documentation/ABI/testing/sysfs-bus-event_source-devices-rdpmc | 44 | ||||
| -rw-r--r-- | arch/x86/events/core.c | 21 | ||||
| -rw-r--r-- | arch/x86/events/intel/core.c | 27 | ||||
| -rw-r--r-- | arch/x86/events/perf_event.h | 6 | ||||
| -rw-r--r-- | arch/x86/include/asm/perf_event.h | 8 |
5 files changed, 104 insertions, 2 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-event_source-devices-rdpmc b/Documentation/ABI/testing/sysfs-bus-event_source-devices-rdpmc new file mode 100644 index 000000000000..59ec18bbb418 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-bus-event_source-devices-rdpmc @@ -0,0 +1,44 @@ +What: /sys/bus/event_source/devices/cpu.../rdpmc +Date: November 2011 +KernelVersion: 3.10 +Contact: Linux kernel mailing list linux-kernel@vger.kernel.org +Description: The /sys/bus/event_source/devices/cpu.../rdpmc attribute + is used to show/manage if rdpmc instruction can be + executed in user space. This attribute supports 3 numbers. + - rdpmc = 0 + user space rdpmc is globally disabled for all PMU + counters. + - rdpmc = 1 + user space rdpmc is globally enabled only in event mmap + ioctl called time window. If the mmap region is unmapped, + user space rdpmc is disabled again. + - rdpmc = 2 + user space rdpmc is globally enabled for all PMU + counters. + + In the Intel platforms supporting counter level's user + space rdpmc disable feature (CPUID.23H.EBX[2] = 1), the + meaning of 3 numbers is extended to + - rdpmc = 0 + global user space rdpmc and counter level's user space + rdpmc of all counters are both disabled. + - rdpmc = 1 + No changes on behavior of global user space rdpmc. + counter level's rdpmc of system-wide events is disabled + but counter level's rdpmc of non-system-wide events is + enabled. + - rdpmc = 2 + global user space rdpmc and counter level's user space + rdpmc of all counters are both enabled unconditionally. + + The default value of rdpmc is 1. + + Please notice: + - global user space rdpmc's behavior would change + immediately along with the rdpmc value's change, + but the behavior of counter level's user space rdpmc + won't take effect immediately until the event is + reactivated or recreated. + - The rdpmc attribute is global, even for x86 hybrid + platforms. For example, changing cpu_core/rdpmc will + also change cpu_atom/rdpmc. diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index c2717cb5034f..6df73e8398cd 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -2616,6 +2616,27 @@ static ssize_t get_attr_rdpmc(struct device *cdev, return snprintf(buf, 40, "%d\n", x86_pmu.attr_rdpmc); } +/* + * Behaviors of rdpmc value: + * - rdpmc = 0 + * global user space rdpmc and counter level's user space rdpmc of all + * counters are both disabled. + * - rdpmc = 1 + * global user space rdpmc is enabled in mmap enabled time window and + * counter level's user space rdpmc is enabled for only non system-wide + * events. Counter level's user space rdpmc of system-wide events is + * still disabled by default. This won't introduce counter data leak for + * non system-wide events since their count data would be cleared when + * context switches. + * - rdpmc = 2 + * global user space rdpmc and counter level's user space rdpmc of all + * counters are enabled unconditionally. + * + * Suppose the rdpmc value won't be changed frequently, don't dynamically + * reschedule events to make the new rpdmc value take effect on active perf + * events immediately, the new rdpmc value would only impact the new + * activated perf events. This makes code simpler and cleaner. + */ static ssize_t set_attr_rdpmc(struct device *cdev, struct device_attribute *attr, const char *buf, size_t count) diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c index d6bdbb7e449a..f3ae1f8ee3cd 100644 --- a/arch/x86/events/intel/core.c +++ b/arch/x86/events/intel/core.c @@ -3128,6 +3128,8 @@ static void intel_pmu_enable_fixed(struct perf_event *event) bits |= INTEL_FIXED_0_USER; if (hwc->config & ARCH_PERFMON_EVENTSEL_OS) bits |= INTEL_FIXED_0_KERNEL; + if (hwc->config & ARCH_PERFMON_EVENTSEL_RDPMC_USER_DISABLE) + bits |= INTEL_FIXED_0_RDPMC_USER_DISABLE; /* * ANY bit is supported in v3 and up @@ -3263,6 +3265,27 @@ static void intel_pmu_enable_event_ext(struct perf_event *event) __intel_pmu_update_event_ext(hwc->idx, ext); } +static void intel_pmu_update_rdpmc_user_disable(struct perf_event *event) +{ + if (!x86_pmu_has_rdpmc_user_disable(event->pmu)) + return; + + /* + * Counter scope's user-space rdpmc is disabled by default + * except two cases. + * a. rdpmc = 2 (user space rdpmc enabled unconditionally) + * b. rdpmc = 1 and the event is not a system-wide event. + * The count of non-system-wide events would be cleared when + * context switches, so no count data is leaked. + */ + if (x86_pmu.attr_rdpmc == X86_USER_RDPMC_ALWAYS_ENABLE || + (x86_pmu.attr_rdpmc == X86_USER_RDPMC_CONDITIONAL_ENABLE && + event->ctx->task)) + event->hw.config &= ~ARCH_PERFMON_EVENTSEL_RDPMC_USER_DISABLE; + else + event->hw.config |= ARCH_PERFMON_EVENTSEL_RDPMC_USER_DISABLE; +} + DEFINE_STATIC_CALL_NULL(intel_pmu_enable_event_ext, intel_pmu_enable_event_ext); static void intel_pmu_enable_event(struct perf_event *event) @@ -3271,6 +3294,8 @@ static void intel_pmu_enable_event(struct perf_event *event) struct hw_perf_event *hwc = &event->hw; int idx = hwc->idx; + intel_pmu_update_rdpmc_user_disable(event); + if (unlikely(event->attr.precise_ip)) static_call(x86_pmu_pebs_enable)(event); @@ -5869,6 +5894,8 @@ static void update_pmu_cap(struct pmu *pmu) hybrid(pmu, config_mask) |= ARCH_PERFMON_EVENTSEL_UMASK2; if (ebx_0.split.eq) hybrid(pmu, config_mask) |= ARCH_PERFMON_EVENTSEL_EQ; + if (ebx_0.split.rdpmc_user_disable) + hybrid(pmu, config_mask) |= ARCH_PERFMON_EVENTSEL_RDPMC_USER_DISABLE; if (eax_0.split.cntr_subleaf) { cpuid_count(ARCH_PERFMON_EXT_LEAF, ARCH_PERFMON_NUM_COUNTER_LEAF, diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h index 24a81d2916e9..cd337f3ffd01 100644 --- a/arch/x86/events/perf_event.h +++ b/arch/x86/events/perf_event.h @@ -1333,6 +1333,12 @@ static inline u64 x86_pmu_get_event_config(struct perf_event *event) return event->attr.config & hybrid(event->pmu, config_mask); } +static inline bool x86_pmu_has_rdpmc_user_disable(struct pmu *pmu) +{ + return !!(hybrid(pmu, config_mask) & + ARCH_PERFMON_EVENTSEL_RDPMC_USER_DISABLE); +} + extern struct event_constraint emptyconstraint; extern struct event_constraint unconstrained; diff --git a/arch/x86/include/asm/perf_event.h b/arch/x86/include/asm/perf_event.h index 0d9af4135e0a..ff5acb8b199b 100644 --- a/arch/x86/include/asm/perf_event.h +++ b/arch/x86/include/asm/perf_event.h @@ -33,6 +33,7 @@ #define ARCH_PERFMON_EVENTSEL_CMASK 0xFF000000ULL #define ARCH_PERFMON_EVENTSEL_BR_CNTR (1ULL << 35) #define ARCH_PERFMON_EVENTSEL_EQ (1ULL << 36) +#define ARCH_PERFMON_EVENTSEL_RDPMC_USER_DISABLE (1ULL << 37) #define ARCH_PERFMON_EVENTSEL_UMASK2 (0xFFULL << 40) #define INTEL_FIXED_BITS_STRIDE 4 @@ -40,6 +41,7 @@ #define INTEL_FIXED_0_USER (1ULL << 1) #define INTEL_FIXED_0_ANYTHREAD (1ULL << 2) #define INTEL_FIXED_0_ENABLE_PMI (1ULL << 3) +#define INTEL_FIXED_0_RDPMC_USER_DISABLE (1ULL << 33) #define INTEL_FIXED_3_METRICS_CLEAR (1ULL << 2) #define HSW_IN_TX (1ULL << 32) @@ -50,7 +52,7 @@ #define INTEL_FIXED_BITS_MASK \ (INTEL_FIXED_0_KERNEL | INTEL_FIXED_0_USER | \ INTEL_FIXED_0_ANYTHREAD | INTEL_FIXED_0_ENABLE_PMI | \ - ICL_FIXED_0_ADAPTIVE) + ICL_FIXED_0_ADAPTIVE | INTEL_FIXED_0_RDPMC_USER_DISABLE) #define intel_fixed_bits_by_idx(_idx, _bits) \ ((_bits) << ((_idx) * INTEL_FIXED_BITS_STRIDE)) @@ -226,7 +228,9 @@ union cpuid35_ebx { unsigned int umask2:1; /* EQ-bit Supported */ unsigned int eq:1; - unsigned int reserved:30; + /* rdpmc user disable Supported */ + unsigned int rdpmc_user_disable:1; + unsigned int reserved:29; } split; unsigned int full; }; |