summaryrefslogtreecommitdiff
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.c20
1 files changed, 20 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index ed63101..6d75b91 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -381,6 +381,20 @@ static void release_pmc_hardware(void) {}
#endif
+static bool check_hw_exists(void)
+{
+ u64 val, val_new = 0;
+ int ret = 0;
+
+ val = 0xabcdUL;
+ ret |= checking_wrmsrl(x86_pmu.perfctr, val);
+ ret |= rdmsrl_safe(x86_pmu.perfctr, &val_new);
+ if (ret || val != val_new)
+ return false;
+
+ return true;
+}
+
static void reserve_ds_buffers(void);
static void release_ds_buffers(void);
@@ -1372,6 +1386,12 @@ void __init init_hw_perf_events(void)
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;
+ }
+
pr_cont("%s PMU driver.\n", x86_pmu.name);
if (x86_pmu.quirks)