perf_counter: Add P6 PMU support
Add basic P6 PMU support. The P6 uses the EVNTSEL0 EN bit to
enable/disable both its counters. We use this for the
global enable/disable, and clear all config bits (except EN)
to disable individual counters.
Actual ia32 hardware doesn't support lfence, so use a locked
op without side-effect to implement a full barrier.
perf stat and perf record seem to function correctly.
[a.p.zijlstra@chello.nl: cleanups and complete the enable/disable code]
Signed-off-by: Vince Weaver <vince@deater.net>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <Pine.LNX.4.64.0907081718450.2715@pianoman.cluster.toy>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/kernel/cpu/perf_counter.c b/arch/x86/kernel/cpu/perf_counter.c
index 36c3dc7..1910f39 100644
--- a/arch/x86/kernel/cpu/perf_counter.c
+++ b/arch/x86/kernel/cpu/perf_counter.c
@@ -66,6 +66,44 @@
};
/*
+ * Not sure about some of these
+ */
+static const u64 p6_perfmon_event_map[] =
+{
+ [PERF_COUNT_HW_CPU_CYCLES] = 0x0079,
+ [PERF_COUNT_HW_INSTRUCTIONS] = 0x00c0,
+ [PERF_COUNT_HW_CACHE_REFERENCES] = 0x0000,
+ [PERF_COUNT_HW_CACHE_MISSES] = 0x0000,
+ [PERF_COUNT_HW_BRANCH_INSTRUCTIONS] = 0x00c4,
+ [PERF_COUNT_HW_BRANCH_MISSES] = 0x00c5,
+ [PERF_COUNT_HW_BUS_CYCLES] = 0x0062,
+};
+
+static u64 p6_pmu_event_map(int event)
+{
+ return p6_perfmon_event_map[event];
+}
+
+static u64 p6_pmu_raw_event(u64 event)
+{
+#define P6_EVNTSEL_EVENT_MASK 0x000000FFULL
+#define P6_EVNTSEL_UNIT_MASK 0x0000FF00ULL
+#define P6_EVNTSEL_EDGE_MASK 0x00040000ULL
+#define P6_EVNTSEL_INV_MASK 0x00800000ULL
+#define P6_EVNTSEL_COUNTER_MASK 0xFF000000ULL
+
+#define P6_EVNTSEL_MASK \
+ (P6_EVNTSEL_EVENT_MASK | \
+ P6_EVNTSEL_UNIT_MASK | \
+ P6_EVNTSEL_EDGE_MASK | \
+ P6_EVNTSEL_INV_MASK | \
+ P6_EVNTSEL_COUNTER_MASK)
+
+ return event & P6_EVNTSEL_MASK;
+}
+
+
+/*
* Intel PerfMon v3. Used on Core2 and later.
*/
static const u64 intel_perfmon_event_map[] =
@@ -726,6 +764,23 @@
return 0;
}
+static void p6_pmu_disable_all(void)
+{
+ struct cpu_hw_counters *cpuc = &__get_cpu_var(cpu_hw_counters);
+ unsigned long val;
+
+ if (!cpuc->enabled)
+ return;
+
+ cpuc->enabled = 0;
+ barrier();
+
+ /* p6 only has one enable register */
+ rdmsrl(MSR_P6_EVNTSEL0, val);
+ val &= ~ARCH_PERFMON_EVENTSEL0_ENABLE;
+ wrmsrl(MSR_P6_EVNTSEL0, val);
+}
+
static void intel_pmu_disable_all(void)
{
wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, 0);
@@ -767,6 +822,23 @@
return x86_pmu.disable_all();
}
+static void p6_pmu_enable_all(void)
+{
+ struct cpu_hw_counters *cpuc = &__get_cpu_var(cpu_hw_counters);
+ unsigned long val;
+
+ if (cpuc->enabled)
+ return;
+
+ cpuc->enabled = 1;
+ barrier();
+
+ /* p6 only has one enable register */
+ rdmsrl(MSR_P6_EVNTSEL0, val);
+ val |= ARCH_PERFMON_EVENTSEL0_ENABLE;
+ wrmsrl(MSR_P6_EVNTSEL0, val);
+}
+
static void intel_pmu_enable_all(void)
{
wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, x86_pmu.intel_ctrl);
@@ -819,16 +891,13 @@
static inline void x86_pmu_enable_counter(struct hw_perf_counter *hwc, int idx)
{
- int err;
- err = checking_wrmsrl(hwc->config_base + idx,
+ (void)checking_wrmsrl(hwc->config_base + idx,
hwc->config | ARCH_PERFMON_EVENTSEL0_ENABLE);
}
static inline void x86_pmu_disable_counter(struct hw_perf_counter *hwc, int idx)
{
- int err;
- err = checking_wrmsrl(hwc->config_base + idx,
- hwc->config);
+ (void)checking_wrmsrl(hwc->config_base + idx, hwc->config);
}
static inline void
@@ -836,13 +905,24 @@
{
int idx = __idx - X86_PMC_IDX_FIXED;
u64 ctrl_val, mask;
- int err;
mask = 0xfULL << (idx * 4);
rdmsrl(hwc->config_base, ctrl_val);
ctrl_val &= ~mask;
- err = checking_wrmsrl(hwc->config_base, ctrl_val);
+ (void)checking_wrmsrl(hwc->config_base, ctrl_val);
+}
+
+static inline void
+p6_pmu_disable_counter(struct hw_perf_counter *hwc, int idx)
+{
+ struct cpu_hw_counters *cpuc = &__get_cpu_var(cpu_hw_counters);
+ unsigned long val = ARCH_PERFMON_EVENTSEL0_ENABLE;
+
+ if (!cpuc->enabled)
+ val = 0;
+
+ (void)checking_wrmsrl(hwc->config_base + idx, val);
}
static inline void
@@ -943,6 +1023,17 @@
err = checking_wrmsrl(hwc->config_base, ctrl_val);
}
+static void p6_pmu_enable_counter(struct hw_perf_counter *hwc, int idx)
+{
+ struct cpu_hw_counters *cpuc = &__get_cpu_var(cpu_hw_counters);
+
+ if (cpuc->enabled)
+ x86_pmu_enable_counter(hwc, idx);
+ else
+ x86_pmu_disable_counter(hwc, idx);
+}
+
+
static void intel_pmu_enable_counter(struct hw_perf_counter *hwc, int idx)
{
if (unlikely(hwc->config_base == MSR_ARCH_PERFMON_FIXED_CTR_CTRL)) {
@@ -1176,6 +1267,49 @@
local_irq_restore(flags);
}
+static int p6_pmu_handle_irq(struct pt_regs *regs)
+{
+ struct perf_sample_data data;
+ struct cpu_hw_counters *cpuc;
+ struct perf_counter *counter;
+ struct hw_perf_counter *hwc;
+ int idx, handled = 0;
+ u64 val;
+
+ data.regs = regs;
+ data.addr = 0;
+
+ cpuc = &__get_cpu_var(cpu_hw_counters);
+
+ for (idx = 0; idx < x86_pmu.num_counters; idx++) {
+ if (!test_bit(idx, cpuc->active_mask))
+ continue;
+
+ counter = cpuc->counters[idx];
+ hwc = &counter->hw;
+
+ val = x86_perf_counter_update(counter, hwc, idx);
+ if (val & (1ULL << (x86_pmu.counter_bits - 1)))
+ continue;
+
+ /*
+ * counter overflow
+ */
+ handled = 1;
+ data.period = counter->hw.last_period;
+
+ if (!x86_perf_counter_set_period(counter, hwc, idx))
+ continue;
+
+ if (perf_counter_overflow(counter, 1, &data))
+ p6_pmu_disable_counter(hwc, idx);
+ }
+
+ if (handled)
+ inc_irq_stat(apic_perf_irqs);
+
+ return handled;
+}
/*
* This handler is triggered by the local APIC, so the APIC IRQ handling
@@ -1185,14 +1319,13 @@
{
struct perf_sample_data data;
struct cpu_hw_counters *cpuc;
- int bit, cpu, loops;
+ int bit, loops;
u64 ack, status;
data.regs = regs;
data.addr = 0;
- cpu = smp_processor_id();
- cpuc = &per_cpu(cpu_hw_counters, cpu);
+ cpuc = &__get_cpu_var(cpu_hw_counters);
perf_disable();
status = intel_pmu_get_status();
@@ -1249,14 +1382,13 @@
struct cpu_hw_counters *cpuc;
struct perf_counter *counter;
struct hw_perf_counter *hwc;
- int cpu, idx, handled = 0;
+ int idx, handled = 0;
u64 val;
data.regs = regs;
data.addr = 0;
- cpu = smp_processor_id();
- cpuc = &per_cpu(cpu_hw_counters, cpu);
+ cpuc = &__get_cpu_var(cpu_hw_counters);
for (idx = 0; idx < x86_pmu.num_counters; idx++) {
if (!test_bit(idx, cpuc->active_mask))
@@ -1353,6 +1485,32 @@
.priority = 1
};
+static struct x86_pmu p6_pmu = {
+ .name = "p6",
+ .handle_irq = p6_pmu_handle_irq,
+ .disable_all = p6_pmu_disable_all,
+ .enable_all = p6_pmu_enable_all,
+ .enable = p6_pmu_enable_counter,
+ .disable = p6_pmu_disable_counter,
+ .eventsel = MSR_P6_EVNTSEL0,
+ .perfctr = MSR_P6_PERFCTR0,
+ .event_map = p6_pmu_event_map,
+ .raw_event = p6_pmu_raw_event,
+ .max_events = ARRAY_SIZE(p6_perfmon_event_map),
+ .max_period = (1ULL << 31) - 1,
+ .version = 0,
+ .num_counters = 2,
+ /*
+ * Counters have 40 bits implemented. However they are designed such
+ * that bits [32-39] are sign extensions of bit 31. As such the
+ * effective width of a counter for P6-like PMU is 32 bits only.
+ *
+ * See IA-32 Intel Architecture Software developer manual Vol 3B
+ */
+ .counter_bits = 32,
+ .counter_mask = (1ULL << 32) - 1,
+};
+
static struct x86_pmu intel_pmu = {
.name = "Intel",
.handle_irq = intel_pmu_handle_irq,
@@ -1392,6 +1550,41 @@
.max_period = (1ULL << 47) - 1,
};
+static int p6_pmu_init(void)
+{
+ int high, low;
+
+ switch (boot_cpu_data.x86_model) {
+ case 1:
+ case 3: /* Pentium Pro */
+ case 5:
+ case 6: /* Pentium II */
+ case 7:
+ case 8:
+ case 11: /* Pentium III */
+ break;
+ case 9:
+ case 13:
+ /* for Pentium M, we need to check if PMU exist */
+ rdmsr(MSR_IA32_MISC_ENABLE, low, high);
+ if (low & MSR_IA32_MISC_ENABLE_EMON)
+ break;
+ default:
+ pr_cont("unsupported p6 CPU model %d ",
+ boot_cpu_data.x86_model);
+ return -ENODEV;
+ }
+
+ if (!cpu_has_apic) {
+ pr_info("no Local APIC, try rebooting with lapic");
+ return -ENODEV;
+ }
+
+ x86_pmu = p6_pmu;
+
+ return 0;
+}
+
static int intel_pmu_init(void)
{
union cpuid10_edx edx;
@@ -1400,8 +1593,14 @@
unsigned int ebx;
int version;
- if (!cpu_has(&boot_cpu_data, X86_FEATURE_ARCH_PERFMON))
+ if (!cpu_has(&boot_cpu_data, X86_FEATURE_ARCH_PERFMON)) {
+ /* check for P6 processor family */
+ if (boot_cpu_data.x86 == 6) {
+ return p6_pmu_init();
+ } else {
return -ENODEV;
+ }
+ }
/*
* Check whether the Architectural PerfMon supports