aboutsummaryrefslogtreecommitdiffstats
path: root/arch/x86/kernel/cpu/perf_event.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/x86/kernel/cpu/perf_event.c')
-rw-r--r--arch/x86/kernel/cpu/perf_event.c107
1 files changed, 76 insertions, 31 deletions
diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index ed6310183efb..04921017abe0 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -330,9 +330,6 @@ static bool reserve_pmc_hardware(void)
{
int i;
- if (nmi_watchdog == NMI_LOCAL_APIC)
- disable_lapic_nmi_watchdog();
-
for (i = 0; i < x86_pmu.num_counters; i++) {
if (!reserve_perfctr_nmi(x86_pmu.perfctr + i))
goto perfctr_fail;
@@ -355,9 +352,6 @@ perfctr_fail:
for (i--; i >= 0; i--)
release_perfctr_nmi(x86_pmu.perfctr + i);
- if (nmi_watchdog == NMI_LOCAL_APIC)
- enable_lapic_nmi_watchdog();
-
return false;
}
@@ -369,9 +363,6 @@ static void release_pmc_hardware(void)
release_perfctr_nmi(x86_pmu.perfctr + i);
release_evntsel_nmi(x86_pmu.eventsel + i);
}
-
- if (nmi_watchdog == NMI_LOCAL_APIC)
- enable_lapic_nmi_watchdog();
}
#else
@@ -381,6 +372,58 @@ static void release_pmc_hardware(void) {}
#endif
+static bool check_hw_exists(void)
+{
+ u64 val, val_new = 0;
+ int i, reg, ret = 0;
+
+ /*
+ * Check to see if the BIOS enabled any of the counters, if so
+ * complain and bail.
+ */
+ for (i = 0; i < x86_pmu.num_counters; i++) {
+ reg = x86_pmu.eventsel + i;
+ ret = rdmsrl_safe(reg, &val);
+ if (ret)
+ goto msr_fail;
+ if (val & ARCH_PERFMON_EVENTSEL_ENABLE)
+ goto bios_fail;
+ }
+
+ if (x86_pmu.num_counters_fixed) {
+ reg = MSR_ARCH_PERFMON_FIXED_CTR_CTRL;
+ ret = rdmsrl_safe(reg, &val);
+ if (ret)
+ goto msr_fail;
+ for (i = 0; i < x86_pmu.num_counters_fixed; i++) {
+ if (val & (0x03 << i*4))
+ goto bios_fail;
+ }
+ }
+
+ /*
+ * Now write a value and read it back to see if it matches,
+ * this is needed to detect certain hardware emulators (qemu/kvm)
+ * that don't trap on the MSR access and always return 0s.
+ */
+ val = 0xabcdUL;
+ ret = checking_wrmsrl(x86_pmu.perfctr, val);
+ ret |= rdmsrl_safe(x86_pmu.perfctr, &val_new);
+ if (ret || val != val_new)
+ goto msr_fail;
+
+ return true;
+
+bios_fail:
+ printk(KERN_CONT "Broken BIOS detected, using software events only.\n");
+ printk(KERN_ERR FW_BUG "the BIOS has corrupted hw-PMU resources (MSR %x is %Lx)\n", reg, val);
+ return false;
+
+msr_fail:
+ printk(KERN_CONT "Broken PMU hardware detected, using software events only.\n");
+ return false;
+}
+
static void reserve_ds_buffers(void);
static void release_ds_buffers(void);
@@ -437,7 +480,7 @@ static int x86_setup_perfctr(struct perf_event *event)
struct hw_perf_event *hwc = &event->hw;
u64 config;
- if (!hwc->sample_period) {
+ if (!is_sampling_event(event)) {
hwc->sample_period = x86_pmu.max_period;
hwc->last_period = hwc->sample_period;
local64_set(&hwc->period_left, hwc->sample_period);
@@ -954,8 +997,7 @@ x86_perf_event_set_period(struct perf_event *event)
static void x86_pmu_enable_event(struct perf_event *event)
{
- struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
- if (cpuc->enabled)
+ if (__this_cpu_read(cpu_hw_events.enabled))
__x86_pmu_enable_event(&event->hw,
ARCH_PERFMON_EVENTSEL_ENABLE);
}
@@ -1229,7 +1271,7 @@ perf_event_nmi_handler(struct notifier_block *self,
break;
case DIE_NMIUNKNOWN:
this_nmi = percpu_read(irq_stat.__nmi_count);
- if (this_nmi != __get_cpu_var(pmu_nmi).marked)
+ if (this_nmi != __this_cpu_read(pmu_nmi.marked))
/* let the kernel handle the unknown nmi */
return NOTIFY_DONE;
/*
@@ -1253,8 +1295,8 @@ perf_event_nmi_handler(struct notifier_block *self,
this_nmi = percpu_read(irq_stat.__nmi_count);
if ((handled > 1) ||
/* the next nmi could be a back-to-back nmi */
- ((__get_cpu_var(pmu_nmi).marked == this_nmi) &&
- (__get_cpu_var(pmu_nmi).handled > 1))) {
+ ((__this_cpu_read(pmu_nmi.marked) == this_nmi) &&
+ (__this_cpu_read(pmu_nmi.handled) > 1))) {
/*
* We could have two subsequent back-to-back nmis: The
* first handles more than one counter, the 2nd
@@ -1265,8 +1307,8 @@ perf_event_nmi_handler(struct notifier_block *self,
* handling more than one counter. We will mark the
* next (3rd) and then drop it if unhandled.
*/
- __get_cpu_var(pmu_nmi).marked = this_nmi + 1;
- __get_cpu_var(pmu_nmi).handled = handled;
+ __this_cpu_write(pmu_nmi.marked, this_nmi + 1);
+ __this_cpu_write(pmu_nmi.handled, handled);
}
return NOTIFY_STOP;
@@ -1348,7 +1390,7 @@ static void __init pmu_check_apic(void)
pr_info("no hardware sampling interrupt available.\n");
}
-void __init init_hw_perf_events(void)
+int __init init_hw_perf_events(void)
{
struct event_constraint *c;
int err;
@@ -1363,15 +1405,19 @@ void __init init_hw_perf_events(void)
err = amd_pmu_init();
break;
default:
- return;
+ return 0;
}
if (err != 0) {
pr_cont("no PMU driver, software events only.\n");
- return;
+ return 0;
}
pmu_check_apic();
+ /* sanity check that the hardware exists or is emulated */
+ if (!check_hw_exists())
+ return 0;
+
pr_cont("%s PMU driver.\n", x86_pmu.name);
if (x86_pmu.quirks)
@@ -1418,9 +1464,12 @@ void __init init_hw_perf_events(void)
pr_info("... fixed-purpose events: %d\n", x86_pmu.num_counters_fixed);
pr_info("... event mask: %016Lx\n", x86_pmu.intel_ctrl);
- perf_pmu_register(&pmu);
+ perf_pmu_register(&pmu, "cpu", PERF_TYPE_RAW);
perf_cpu_notifier(x86_pmu_notifier);
+
+ return 0;
}
+early_initcall(init_hw_perf_events);
static inline void x86_pmu_read(struct perf_event *event)
{
@@ -1434,11 +1483,9 @@ static inline void x86_pmu_read(struct perf_event *event)
*/
static void x86_pmu_start_txn(struct pmu *pmu)
{
- struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
-
perf_pmu_disable(pmu);
- cpuc->group_flag |= PERF_EVENT_TXN;
- cpuc->n_txn = 0;
+ __this_cpu_or(cpu_hw_events.group_flag, PERF_EVENT_TXN);
+ __this_cpu_write(cpu_hw_events.n_txn, 0);
}
/*
@@ -1448,14 +1495,12 @@ static void x86_pmu_start_txn(struct pmu *pmu)
*/
static void x86_pmu_cancel_txn(struct pmu *pmu)
{
- struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
-
- cpuc->group_flag &= ~PERF_EVENT_TXN;
+ __this_cpu_and(cpu_hw_events.group_flag, ~PERF_EVENT_TXN);
/*
* Truncate the collected events.
*/
- cpuc->n_added -= cpuc->n_txn;
- cpuc->n_events -= cpuc->n_txn;
+ __this_cpu_sub(cpu_hw_events.n_added, __this_cpu_read(cpu_hw_events.n_txn));
+ __this_cpu_sub(cpu_hw_events.n_events, __this_cpu_read(cpu_hw_events.n_txn));
perf_pmu_enable(pmu);
}
@@ -1666,7 +1711,7 @@ perf_callchain_kernel(struct perf_callchain_entry *entry, struct pt_regs *regs)
perf_callchain_store(entry, regs->ip);
- dump_trace(NULL, regs, NULL, regs->bp, &backtrace_ops, entry);
+ dump_trace(NULL, regs, NULL, &backtrace_ops, entry);
}
#ifdef CONFIG_COMPAT
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.