1 files changed, 52 insertions, 22 deletions

diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index 6d75b9145b1..0a360d14659 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
@@ -384,15 +375,53 @@ static void release_pmc_hardware(void) {}
 static bool check_hw_exists(void)
 {
         u64 val, val_new = 0;
-        int ret = 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 = checking_wrmsrl(x86_pmu.perfctr, val);
         ret |= rdmsrl_safe(x86_pmu.perfctr, &val_new);
         if (ret || val != val_new)
-                return false;
+                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);
@@ -451,7 +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);
@@ -1362,7 +1391,7 @@ 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;
@@ -1377,20 +1406,18 @@ 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()) {
-                pr_cont("Broken PMU hardware detected, software events only.\n");
-                return;
-        }
+        if (!check_hw_exists())
+                return 0;
 
         pr_cont("%s PMU driver.\n", x86_pmu.name);
 
@@ -1438,9 +1465,12 @@ 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)
 {
@@ -1686,7 +1716,7 @@ 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