#include <linux/nmi.h>
#include <linux/module.h>
- /* For reliability, we're prepared to waste bits here. */
- static DECLARE_BITMAP(backtrace_mask, NR_CPUS) __read_mostly;
-
+#ifdef CONFIG_HARDLOCKUP_DETECTOR
u64 hw_nmi_get_sample_period(void)
{
return (u64)(cpu_khz) * 1000 * 60;
}
+#endif
-#ifdef ARCH_HAS_NMI_WATCHDOG
+
+ /* For reliability, we're prepared to waste bits here. */
+ static DECLARE_BITMAP(backtrace_mask, NR_CPUS) __read_mostly;
+
+#ifdef arch_trigger_all_cpu_backtrace
void arch_trigger_all_cpu_backtrace(void)
{
int i;
#endif
/* STUB calls to mimic old nmi_watchdog behaviour */
-#if defined(CONFIG_X86_LOCAL_APIC)
-unsigned int nmi_watchdog = NMI_NONE;
-EXPORT_SYMBOL(nmi_watchdog);
-void acpi_nmi_enable(void) { return; }
-void acpi_nmi_disable(void) { return; }
-#endif
-atomic_t nmi_active = ATOMIC_INIT(0); /* oprofile uses this */
-EXPORT_SYMBOL(nmi_active);
int unknown_nmi_panic;
-void cpu_nmi_set_wd_enabled(void) { return; }
-void stop_apic_nmi_watchdog(void *unused) { return; }
-void setup_apic_nmi_watchdog(void *unused) { return; }
-int __init check_nmi_watchdog(void) { return 0; }
{
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;
for (i--; i >= 0; i--)
release_perfctr_nmi(x86_pmu.perfctr + i);
- if (nmi_watchdog == NMI_LOCAL_APIC)
- enable_lapic_nmi_watchdog();
-
return false;
}
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
#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);
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)
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
#include <linux/kernel_stat.h>
#include <linux/perf_event.h>
#include <linux/ftrace_event.h>
+ #include <linux/hw_breakpoint.h>
#include <asm/irq_regs.h>
{
int ctxn;
- perf_sw_event(PERF_COUNT_SW_CONTEXT_SWITCHES, 1, 1, NULL, 0);
-
for_each_task_context_nr(ctxn)
perf_event_context_sched_out(task, ctxn, next);
}
{
raw_spin_lock(&ctx->lock);
- /* Rotate the first entry last of non-pinned groups */
- list_rotate_left(&ctx->flexible_groups);
+ /*
+ * Rotate the first entry last of non-pinned groups. Rotation might be
+ * disabled by the inheritance code.
+ */
+ if (!ctx->rotate_disable)
+ list_rotate_left(&ctx->flexible_groups);
raw_spin_unlock(&ctx->lock);
}
raw_spin_unlock_irq(&ctx->lock);
mutex_unlock(&ctx->mutex);
- mutex_lock(&event->owner->perf_event_mutex);
- list_del_init(&event->owner_entry);
- mutex_unlock(&event->owner->perf_event_mutex);
- put_task_struct(event->owner);
-
free_event(event);
return 0;
static int perf_release(struct inode *inode, struct file *file)
{
struct perf_event *event = file->private_data;
+ struct task_struct *owner;
file->private_data = NULL;
+ rcu_read_lock();
+ owner = ACCESS_ONCE(event->owner);
+ /*
+ * Matches the smp_wmb() in perf_event_exit_task(). If we observe
+ * !owner it means the list deletion is complete and we can indeed
+ * free this event, otherwise we need to serialize on
+ * owner->perf_event_mutex.
+ */
+ smp_read_barrier_depends();
+ if (owner) {
+ /*
+ * Since delayed_put_task_struct() also drops the last
+ * task reference we can safely take a new reference
+ * while holding the rcu_read_lock().
+ */
+ get_task_struct(owner);
+ }
+ rcu_read_unlock();
+
+ if (owner) {
+ mutex_lock(&owner->perf_event_mutex);
+ /*
+ * We have to re-check the event->owner field, if it is cleared
+ * we raced with perf_event_exit_task(), acquiring the mutex
+ * ensured they're done, and we can proceed with freeing the
+ * event.
+ */
+ if (event->owner)
+ list_del_init(&event->owner_entry);
+ mutex_unlock(&owner->perf_event_mutex);
+ put_task_struct(owner);
+ }
+
return perf_event_release_kernel(event);
}
if (event->attr.type != PERF_TYPE_TRACEPOINT)
return -ENOENT;
- /*
- * Raw tracepoint data is a severe data leak, only allow root to
- * have these.
- */
- if ((event->attr.sample_type & PERF_SAMPLE_RAW) &&
- perf_paranoid_tracepoint_raw() &&
- !capable(CAP_SYS_ADMIN))
- return -EPERM;
-
err = perf_trace_init(event);
if (err)
return err;
mutex_unlock(&ctx->mutex);
event->owner = current;
- get_task_struct(current);
+
mutex_lock(¤t->perf_event_mutex);
list_add_tail(&event->owner_entry, ¤t->perf_event_list);
mutex_unlock(¤t->perf_event_mutex);
++ctx->generation;
mutex_unlock(&ctx->mutex);
- event->owner = current;
- get_task_struct(current);
- mutex_lock(¤t->perf_event_mutex);
- list_add_tail(&event->owner_entry, ¤t->perf_event_list);
- mutex_unlock(¤t->perf_event_mutex);
-
return event;
err_free:
*/
void perf_event_exit_task(struct task_struct *child)
{
+ struct perf_event *event, *tmp;
int ctxn;
+ mutex_lock(&child->perf_event_mutex);
+ list_for_each_entry_safe(event, tmp, &child->perf_event_list,
+ owner_entry) {
+ list_del_init(&event->owner_entry);
+
+ /*
+ * Ensure the list deletion is visible before we clear
+ * the owner, closes a race against perf_release() where
+ * we need to serialize on the owner->perf_event_mutex.
+ */
+ smp_wmb();
+ event->owner = NULL;
+ }
+ mutex_unlock(&child->perf_event_mutex);
+
for_each_task_context_nr(ctxn)
perf_event_exit_task_context(child, ctxn);
}
struct perf_event *event;
struct task_struct *parent = current;
int inherited_all = 1;
+ unsigned long flags;
int ret = 0;
child->perf_event_ctxp[ctxn] = NULL;
break;
}
+ /*
+ * We can't hold ctx->lock when iterating the ->flexible_group list due
+ * to allocations, but we need to prevent rotation because
+ * rotate_ctx() will change the list from interrupt context.
+ */
+ raw_spin_lock_irqsave(&parent_ctx->lock, flags);
+ parent_ctx->rotate_disable = 1;
+ raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
+
list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
ret = inherit_task_group(event, parent, parent_ctx,
child, ctxn, &inherited_all);
break;
}
+ raw_spin_lock_irqsave(&parent_ctx->lock, flags);
+ parent_ctx->rotate_disable = 0;
+ raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
+
child_ctx = child->perf_event_ctxp[ctxn];
if (child_ctx && inherited_all) {
void __init perf_event_init(void)
{
+ int ret;
+
perf_event_init_all_cpus();
init_srcu_struct(&pmus_srcu);
perf_pmu_register(&perf_swevent);
perf_pmu_register(&perf_task_clock);
perf_tp_register();
perf_cpu_notifier(perf_cpu_notify);
+
+ ret = init_hw_breakpoint();
+ WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
}
projects / mirror_ubuntu-bionic-kernel.git / commitdiff