/*
* event overflow
*/
- handled = 1;
+ handled++;
data.period = event->hw.last_period;
if (!x86_perf_event_set_period(event))
apic_write(APIC_LVTPC, APIC_DM_NMI);
}
+struct pmu_nmi_state {
+ unsigned int marked;
+ int handled;
+};
+
+static DEFINE_PER_CPU(struct pmu_nmi_state, pmu_nmi);
+
static int __kprobes
perf_event_nmi_handler(struct notifier_block *self,
unsigned long cmd, void *__args)
{
struct die_args *args = __args;
- struct pt_regs *regs;
+ unsigned int this_nmi;
+ int handled;
if (!atomic_read(&active_events))
return NOTIFY_DONE;
case DIE_NMI:
case DIE_NMI_IPI:
break;
-
+ case DIE_NMIUNKNOWN:
+ this_nmi = percpu_read(irq_stat.__nmi_count);
+ if (this_nmi != __get_cpu_var(pmu_nmi).marked)
+ /* let the kernel handle the unknown nmi */
+ return NOTIFY_DONE;
+ /*
+ * This one is a PMU back-to-back nmi. Two events
+ * trigger 'simultaneously' raising two back-to-back
+ * NMIs. If the first NMI handles both, the latter
+ * will be empty and daze the CPU. So, we drop it to
+ * avoid false-positive 'unknown nmi' messages.
+ */
+ return NOTIFY_STOP;
default:
return NOTIFY_DONE;
}
- regs = args->regs;
-
apic_write(APIC_LVTPC, APIC_DM_NMI);
- /*
- * Can't rely on the handled return value to say it was our NMI, two
- * events could trigger 'simultaneously' raising two back-to-back NMIs.
- *
- * If the first NMI handles both, the latter will be empty and daze
- * the CPU.
- */
- x86_pmu.handle_irq(regs);
+
+ handled = x86_pmu.handle_irq(args->regs);
+ if (!handled)
+ return NOTIFY_DONE;
+
+ 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))) {
+ /*
+ * We could have two subsequent back-to-back nmis: The
+ * first handles more than one counter, the 2nd
+ * handles only one counter and the 3rd handles no
+ * counter.
+ *
+ * This is the 2nd nmi because the previous was
+ * 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;
+ }
return NOTIFY_STOP;
}
* callchain support
*/
-static inline
-void callchain_store(struct perf_callchain_entry *entry, u64 ip)
-{
- if (entry->nr < PERF_MAX_STACK_DEPTH)
- entry->ip[entry->nr++] = ip;
-}
-
-static DEFINE_PER_CPU(struct perf_callchain_entry, pmc_irq_entry);
-static DEFINE_PER_CPU(struct perf_callchain_entry, pmc_nmi_entry);
-
-
static void
backtrace_warning_symbol(void *data, char *msg, unsigned long symbol)
{
{
struct perf_callchain_entry *entry = data;
- callchain_store(entry, addr);
+ perf_callchain_store(entry, addr);
}
static const struct stacktrace_ops backtrace_ops = {
.walk_stack = print_context_stack_bp,
};
-static void
-perf_callchain_kernel(struct pt_regs *regs, struct perf_callchain_entry *entry)
+void
+perf_callchain_kernel(struct perf_callchain_entry *entry, struct pt_regs *regs)
{
- callchain_store(entry, PERF_CONTEXT_KERNEL);
- callchain_store(entry, regs->ip);
+ if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) {
+ /* TODO: We don't support guest os callchain now */
+ return;
+ }
+
+ perf_callchain_store(entry, regs->ip);
dump_trace(NULL, regs, NULL, regs->bp, &backtrace_ops, entry);
}
if (fp < compat_ptr(regs->sp))
break;
- callchain_store(entry, frame.return_address);
+ perf_callchain_store(entry, frame.return_address);
fp = compat_ptr(frame.next_frame);
}
return 1;
}
#endif
-static void
-perf_callchain_user(struct pt_regs *regs, struct perf_callchain_entry *entry)
+void
+perf_callchain_user(struct perf_callchain_entry *entry, struct pt_regs *regs)
{
struct stack_frame frame;
const void __user *fp;
- if (!user_mode(regs))
- regs = task_pt_regs(current);
+ if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) {
+ /* TODO: We don't support guest os callchain now */
+ return;
+ }
fp = (void __user *)regs->bp;
- callchain_store(entry, PERF_CONTEXT_USER);
- callchain_store(entry, regs->ip);
+ perf_callchain_store(entry, regs->ip);
if (perf_callchain_user32(regs, entry))
return;
if ((unsigned long)fp < regs->sp)
break;
- callchain_store(entry, frame.return_address);
+ perf_callchain_store(entry, frame.return_address);
fp = frame.next_frame;
}
}
-static void
-perf_do_callchain(struct pt_regs *regs, struct perf_callchain_entry *entry)
-{
- int is_user;
-
- if (!regs)
- return;
-
- is_user = user_mode(regs);
-
- if (is_user && current->state != TASK_RUNNING)
- return;
-
- if (!is_user)
- perf_callchain_kernel(regs, entry);
-
- if (current->mm)
- perf_callchain_user(regs, entry);
-}
-
-struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
-{
- struct perf_callchain_entry *entry;
-
- if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) {
- /* TODO: We don't support guest os callchain now */
- return NULL;
- }
-
- if (in_nmi())
- entry = &__get_cpu_var(pmc_nmi_entry);
- else
- entry = &__get_cpu_var(pmc_irq_entry);
-
- entry->nr = 0;
-
- perf_do_callchain(regs, entry);
-
- return entry;
-}
-
unsigned long perf_instruction_pointer(struct pt_regs *regs)
{
unsigned long ip;
projects / mv-sheeva.git / blobdiff