--- /dev/null
+/*
+ * Performance events core code:
+ *
+ * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
+ * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
+ * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
+ * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
+ *
+ * For licensing details see kernel-base/COPYING
+ */
+
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/cpu.h>
+#include <linux/smp.h>
+#include <linux/idr.h>
+#include <linux/file.h>
+#include <linux/poll.h>
+#include <linux/slab.h>
+#include <linux/hash.h>
+#include <linux/sysfs.h>
+#include <linux/dcache.h>
+#include <linux/percpu.h>
+#include <linux/ptrace.h>
+#include <linux/reboot.h>
+#include <linux/vmstat.h>
+#include <linux/device.h>
+#include <linux/vmalloc.h>
+#include <linux/hardirq.h>
+#include <linux/rculist.h>
+#include <linux/uaccess.h>
+#include <linux/syscalls.h>
+#include <linux/anon_inodes.h>
+#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>
+
+struct remote_function_call {
+ struct task_struct *p;
+ int (*func)(void *info);
+ void *info;
+ int ret;
+};
+
+static void remote_function(void *data)
+{
+ struct remote_function_call *tfc = data;
+ struct task_struct *p = tfc->p;
+
+ if (p) {
+ tfc->ret = -EAGAIN;
+ if (task_cpu(p) != smp_processor_id() || !task_curr(p))
+ return;
+ }
+
+ tfc->ret = tfc->func(tfc->info);
+}
+
+/**
+ * task_function_call - call a function on the cpu on which a task runs
+ * @p: the task to evaluate
+ * @func: the function to be called
+ * @info: the function call argument
+ *
+ * Calls the function @func when the task is currently running. This might
+ * be on the current CPU, which just calls the function directly
+ *
+ * returns: @func return value, or
+ * -ESRCH - when the process isn't running
+ * -EAGAIN - when the process moved away
+ */
+static int
+task_function_call(struct task_struct *p, int (*func) (void *info), void *info)
+{
+ struct remote_function_call data = {
+ .p = p,
+ .func = func,
+ .info = info,
+ .ret = -ESRCH, /* No such (running) process */
+ };
+
+ if (task_curr(p))
+ smp_call_function_single(task_cpu(p), remote_function, &data, 1);
+
+ return data.ret;
+}
+
+/**
+ * cpu_function_call - call a function on the cpu
+ * @func: the function to be called
+ * @info: the function call argument
+ *
+ * Calls the function @func on the remote cpu.
+ *
+ * returns: @func return value or -ENXIO when the cpu is offline
+ */
+static int cpu_function_call(int cpu, int (*func) (void *info), void *info)
+{
+ struct remote_function_call data = {
+ .p = NULL,
+ .func = func,
+ .info = info,
+ .ret = -ENXIO, /* No such CPU */
+ };
+
+ smp_call_function_single(cpu, remote_function, &data, 1);
+
+ return data.ret;
+}
+
+#define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
+ PERF_FLAG_FD_OUTPUT |\
+ PERF_FLAG_PID_CGROUP)
+
+enum event_type_t {
+ EVENT_FLEXIBLE = 0x1,
+ EVENT_PINNED = 0x2,
+ EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
+};
+
+/*
+ * perf_sched_events : >0 events exist
+ * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
+ */
+struct jump_label_key perf_sched_events __read_mostly;
+static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
+
+static atomic_t nr_mmap_events __read_mostly;
+static atomic_t nr_comm_events __read_mostly;
+static atomic_t nr_task_events __read_mostly;
+
+static LIST_HEAD(pmus);
+static DEFINE_MUTEX(pmus_lock);
+static struct srcu_struct pmus_srcu;
+
+/*
+ * perf event paranoia level:
+ * -1 - not paranoid at all
+ * 0 - disallow raw tracepoint access for unpriv
+ * 1 - disallow cpu events for unpriv
+ * 2 - disallow kernel profiling for unpriv
+ */
+int sysctl_perf_event_paranoid __read_mostly = 1;
+
+/* Minimum for 512 kiB + 1 user control page */
+int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
+
+/*
+ * max perf event sample rate
+ */
+#define DEFAULT_MAX_SAMPLE_RATE 100000
+int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
+static int max_samples_per_tick __read_mostly =
+ DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
+
+int perf_proc_update_handler(struct ctl_table *table, int write,
+ void __user *buffer, size_t *lenp,
+ loff_t *ppos)
+{
+ int ret = proc_dointvec(table, write, buffer, lenp, ppos);
+
+ if (ret || !write)
+ return ret;
+
+ max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
+
+ return 0;
+}
+
+static atomic64_t perf_event_id;
+
+static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
+ enum event_type_t event_type);
+
+static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
+ enum event_type_t event_type,
+ struct task_struct *task);
+
+static void update_context_time(struct perf_event_context *ctx);
+static u64 perf_event_time(struct perf_event *event);
+
+void __weak perf_event_print_debug(void) { }
+
+extern __weak const char *perf_pmu_name(void)
+{
+ return "pmu";
+}
+
+static inline u64 perf_clock(void)
+{
+ return local_clock();
+}
+
+static inline struct perf_cpu_context *
+__get_cpu_context(struct perf_event_context *ctx)
+{
+ return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
+}
+
+#ifdef CONFIG_CGROUP_PERF
+
+/*
+ * Must ensure cgroup is pinned (css_get) before calling
+ * this function. In other words, we cannot call this function
+ * if there is no cgroup event for the current CPU context.
+ */
+static inline struct perf_cgroup *
+perf_cgroup_from_task(struct task_struct *task)
+{
+ return container_of(task_subsys_state(task, perf_subsys_id),
+ struct perf_cgroup, css);
+}
+
+static inline bool
+perf_cgroup_match(struct perf_event *event)
+{
+ struct perf_event_context *ctx = event->ctx;
+ struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
+
+ return !event->cgrp || event->cgrp == cpuctx->cgrp;
+}
+
+static inline void perf_get_cgroup(struct perf_event *event)
+{
+ css_get(&event->cgrp->css);
+}
+
+static inline void perf_put_cgroup(struct perf_event *event)
+{
+ css_put(&event->cgrp->css);
+}
+
+static inline void perf_detach_cgroup(struct perf_event *event)
+{
+ perf_put_cgroup(event);
+ event->cgrp = NULL;
+}
+
+static inline int is_cgroup_event(struct perf_event *event)
+{
+ return event->cgrp != NULL;
+}
+
+static inline u64 perf_cgroup_event_time(struct perf_event *event)
+{
+ struct perf_cgroup_info *t;
+
+ t = per_cpu_ptr(event->cgrp->info, event->cpu);
+ return t->time;
+}
+
+static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
+{
+ struct perf_cgroup_info *info;
+ u64 now;
+
+ now = perf_clock();
+
+ info = this_cpu_ptr(cgrp->info);
+
+ info->time += now - info->timestamp;
+ info->timestamp = now;
+}
+
+static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
+{
+ struct perf_cgroup *cgrp_out = cpuctx->cgrp;
+ if (cgrp_out)
+ __update_cgrp_time(cgrp_out);
+}
+
+static inline void update_cgrp_time_from_event(struct perf_event *event)
+{
+ struct perf_cgroup *cgrp;
+
+ /*
+ * ensure we access cgroup data only when needed and
+ * when we know the cgroup is pinned (css_get)
+ */
+ if (!is_cgroup_event(event))
+ return;
+
+ cgrp = perf_cgroup_from_task(current);
+ /*
+ * Do not update time when cgroup is not active
+ */
+ if (cgrp == event->cgrp)
+ __update_cgrp_time(event->cgrp);
+}
+
+static inline void
+perf_cgroup_set_timestamp(struct task_struct *task,
+ struct perf_event_context *ctx)
+{
+ struct perf_cgroup *cgrp;
+ struct perf_cgroup_info *info;
+
+ /*
+ * ctx->lock held by caller
+ * ensure we do not access cgroup data
+ * unless we have the cgroup pinned (css_get)
+ */
+ if (!task || !ctx->nr_cgroups)
+ return;
+
+ cgrp = perf_cgroup_from_task(task);
+ info = this_cpu_ptr(cgrp->info);
+ info->timestamp = ctx->timestamp;
+}
+
+#define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
+#define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
+
+/*
+ * reschedule events based on the cgroup constraint of task.
+ *
+ * mode SWOUT : schedule out everything
+ * mode SWIN : schedule in based on cgroup for next
+ */
+void perf_cgroup_switch(struct task_struct *task, int mode)
+{
+ struct perf_cpu_context *cpuctx;
+ struct pmu *pmu;
+ unsigned long flags;
+
+ /*
+ * disable interrupts to avoid geting nr_cgroup
+ * changes via __perf_event_disable(). Also
+ * avoids preemption.
+ */
+ local_irq_save(flags);
+
+ /*
+ * we reschedule only in the presence of cgroup
+ * constrained events.
+ */
+ rcu_read_lock();
+
+ list_for_each_entry_rcu(pmu, &pmus, entry) {
+
+ cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
+
+ perf_pmu_disable(cpuctx->ctx.pmu);
+
+ /*
+ * perf_cgroup_events says at least one
+ * context on this CPU has cgroup events.
+ *
+ * ctx->nr_cgroups reports the number of cgroup
+ * events for a context.
+ */
+ if (cpuctx->ctx.nr_cgroups > 0) {
+
+ if (mode & PERF_CGROUP_SWOUT) {
+ cpu_ctx_sched_out(cpuctx, EVENT_ALL);
+ /*
+ * must not be done before ctxswout due
+ * to event_filter_match() in event_sched_out()
+ */
+ cpuctx->cgrp = NULL;
+ }
+
+ if (mode & PERF_CGROUP_SWIN) {
+ WARN_ON_ONCE(cpuctx->cgrp);
+ /* set cgrp before ctxsw in to
+ * allow event_filter_match() to not
+ * have to pass task around
+ */
+ cpuctx->cgrp = perf_cgroup_from_task(task);
+ cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
+ }
+ }
+
+ perf_pmu_enable(cpuctx->ctx.pmu);
+ }
+
+ rcu_read_unlock();
+
+ local_irq_restore(flags);
+}
+
+static inline void perf_cgroup_sched_out(struct task_struct *task)
+{
+ perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
+}
+
+static inline void perf_cgroup_sched_in(struct task_struct *task)
+{
+ perf_cgroup_switch(task, PERF_CGROUP_SWIN);
+}
+
+static inline int perf_cgroup_connect(int fd, struct perf_event *event,
+ struct perf_event_attr *attr,
+ struct perf_event *group_leader)
+{
+ struct perf_cgroup *cgrp;
+ struct cgroup_subsys_state *css;
+ struct file *file;
+ int ret = 0, fput_needed;
+
+ file = fget_light(fd, &fput_needed);
+ if (!file)
+ return -EBADF;
+
+ css = cgroup_css_from_dir(file, perf_subsys_id);
+ if (IS_ERR(css)) {
+ ret = PTR_ERR(css);
+ goto out;
+ }
+
+ cgrp = container_of(css, struct perf_cgroup, css);
+ event->cgrp = cgrp;
+
+ /* must be done before we fput() the file */
+ perf_get_cgroup(event);
+
+ /*
+ * all events in a group must monitor
+ * the same cgroup because a task belongs
+ * to only one perf cgroup at a time
+ */
+ if (group_leader && group_leader->cgrp != cgrp) {
+ perf_detach_cgroup(event);
+ ret = -EINVAL;
+ }
+out:
+ fput_light(file, fput_needed);
+ return ret;
+}
+
+static inline void
+perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
+{
+ struct perf_cgroup_info *t;
+ t = per_cpu_ptr(event->cgrp->info, event->cpu);
+ event->shadow_ctx_time = now - t->timestamp;
+}
+
+static inline void
+perf_cgroup_defer_enabled(struct perf_event *event)
+{
+ /*
+ * when the current task's perf cgroup does not match
+ * the event's, we need to remember to call the
+ * perf_mark_enable() function the first time a task with
+ * a matching perf cgroup is scheduled in.
+ */
+ if (is_cgroup_event(event) && !perf_cgroup_match(event))
+ event->cgrp_defer_enabled = 1;
+}
+
+static inline void
+perf_cgroup_mark_enabled(struct perf_event *event,
+ struct perf_event_context *ctx)
+{
+ struct perf_event *sub;
+ u64 tstamp = perf_event_time(event);
+
+ if (!event->cgrp_defer_enabled)
+ return;
+
+ event->cgrp_defer_enabled = 0;
+
+ event->tstamp_enabled = tstamp - event->total_time_enabled;
+ list_for_each_entry(sub, &event->sibling_list, group_entry) {
+ if (sub->state >= PERF_EVENT_STATE_INACTIVE) {
+ sub->tstamp_enabled = tstamp - sub->total_time_enabled;
+ sub->cgrp_defer_enabled = 0;
+ }
+ }
+}
+#else /* !CONFIG_CGROUP_PERF */
+
+static inline bool
+perf_cgroup_match(struct perf_event *event)
+{
+ return true;
+}
+
+static inline void perf_detach_cgroup(struct perf_event *event)
+{}
+
+static inline int is_cgroup_event(struct perf_event *event)
+{
+ return 0;
+}
+
+static inline u64 perf_cgroup_event_cgrp_time(struct perf_event *event)
+{
+ return 0;
+}
+
+static inline void update_cgrp_time_from_event(struct perf_event *event)
+{
+}
+
+static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
+{
+}
+
+static inline void perf_cgroup_sched_out(struct task_struct *task)
+{
+}
+
+static inline void perf_cgroup_sched_in(struct task_struct *task)
+{
+}
+
+static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
+ struct perf_event_attr *attr,
+ struct perf_event *group_leader)
+{
+ return -EINVAL;
+}
+
+static inline void
+perf_cgroup_set_timestamp(struct task_struct *task,
+ struct perf_event_context *ctx)
+{
+}
+
+void
+perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
+{
+}
+
+static inline void
+perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
+{
+}
+
+static inline u64 perf_cgroup_event_time(struct perf_event *event)
+{
+ return 0;
+}
+
+static inline void
+perf_cgroup_defer_enabled(struct perf_event *event)
+{
+}
+
+static inline void
+perf_cgroup_mark_enabled(struct perf_event *event,
+ struct perf_event_context *ctx)
+{
+}
+#endif
+
+void perf_pmu_disable(struct pmu *pmu)
+{
+ int *count = this_cpu_ptr(pmu->pmu_disable_count);
+ if (!(*count)++)
+ pmu->pmu_disable(pmu);
+}
+
+void perf_pmu_enable(struct pmu *pmu)
+{
+ int *count = this_cpu_ptr(pmu->pmu_disable_count);
+ if (!--(*count))
+ pmu->pmu_enable(pmu);
+}
+
+static DEFINE_PER_CPU(struct list_head, rotation_list);
+
+/*
+ * perf_pmu_rotate_start() and perf_rotate_context() are fully serialized
+ * because they're strictly cpu affine and rotate_start is called with IRQs
+ * disabled, while rotate_context is called from IRQ context.
+ */
+static void perf_pmu_rotate_start(struct pmu *pmu)
+{
+ struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
+ struct list_head *head = &__get_cpu_var(rotation_list);
+
+ WARN_ON(!irqs_disabled());
+
+ if (list_empty(&cpuctx->rotation_list))
+ list_add(&cpuctx->rotation_list, head);
+}
+
+static void get_ctx(struct perf_event_context *ctx)
+{
+ WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
+}
+
- static void free_ctx(struct rcu_head *head)
- {
- struct perf_event_context *ctx;
-
- ctx = container_of(head, struct perf_event_context, rcu_head);
- kfree(ctx);
- }
-
+static void put_ctx(struct perf_event_context *ctx)
+{
+ if (atomic_dec_and_test(&ctx->refcount)) {
+ if (ctx->parent_ctx)
+ put_ctx(ctx->parent_ctx);
+ if (ctx->task)
+ put_task_struct(ctx->task);
- call_rcu(&ctx->rcu_head, free_ctx);
++ kfree_rcu(ctx, rcu_head);
+ }
+}
+
+static void unclone_ctx(struct perf_event_context *ctx)
+{
+ if (ctx->parent_ctx) {
+ put_ctx(ctx->parent_ctx);
+ ctx->parent_ctx = NULL;
+ }
+}
+
+static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
+{
+ /*
+ * only top level events have the pid namespace they were created in
+ */
+ if (event->parent)
+ event = event->parent;
+
+ return task_tgid_nr_ns(p, event->ns);
+}
+
+static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
+{
+ /*
+ * only top level events have the pid namespace they were created in
+ */
+ if (event->parent)
+ event = event->parent;
+
+ return task_pid_nr_ns(p, event->ns);
+}
+
+/*
+ * If we inherit events we want to return the parent event id
+ * to userspace.
+ */
+static u64 primary_event_id(struct perf_event *event)
+{
+ u64 id = event->id;
+
+ if (event->parent)
+ id = event->parent->id;
+
+ return id;
+}
+
+/*
+ * Get the perf_event_context for a task and lock it.
+ * This has to cope with with the fact that until it is locked,
+ * the context could get moved to another task.
+ */
+static struct perf_event_context *
+perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
+{
+ struct perf_event_context *ctx;
+
+ rcu_read_lock();
+retry:
+ ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
+ if (ctx) {
+ /*
+ * If this context is a clone of another, it might
+ * get swapped for another underneath us by
+ * perf_event_task_sched_out, though the
+ * rcu_read_lock() protects us from any context
+ * getting freed. Lock the context and check if it
+ * got swapped before we could get the lock, and retry
+ * if so. If we locked the right context, then it
+ * can't get swapped on us any more.
+ */
+ raw_spin_lock_irqsave(&ctx->lock, *flags);
+ if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
+ raw_spin_unlock_irqrestore(&ctx->lock, *flags);
+ goto retry;
+ }
+
+ if (!atomic_inc_not_zero(&ctx->refcount)) {
+ raw_spin_unlock_irqrestore(&ctx->lock, *flags);
+ ctx = NULL;
+ }
+ }
+ rcu_read_unlock();
+ return ctx;
+}
+
+/*
+ * Get the context for a task and increment its pin_count so it
+ * can't get swapped to another task. This also increments its
+ * reference count so that the context can't get freed.
+ */
+static struct perf_event_context *
+perf_pin_task_context(struct task_struct *task, int ctxn)
+{
+ struct perf_event_context *ctx;
+ unsigned long flags;
+
+ ctx = perf_lock_task_context(task, ctxn, &flags);
+ if (ctx) {
+ ++ctx->pin_count;
+ raw_spin_unlock_irqrestore(&ctx->lock, flags);
+ }
+ return ctx;
+}
+
+static void perf_unpin_context(struct perf_event_context *ctx)
+{
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&ctx->lock, flags);
+ --ctx->pin_count;
+ raw_spin_unlock_irqrestore(&ctx->lock, flags);
+}
+
+/*
+ * Update the record of the current time in a context.
+ */
+static void update_context_time(struct perf_event_context *ctx)
+{
+ u64 now = perf_clock();
+
+ ctx->time += now - ctx->timestamp;
+ ctx->timestamp = now;
+}
+
+static u64 perf_event_time(struct perf_event *event)
+{
+ struct perf_event_context *ctx = event->ctx;
+
+ if (is_cgroup_event(event))
+ return perf_cgroup_event_time(event);
+
+ return ctx ? ctx->time : 0;
+}
+
+/*
+ * Update the total_time_enabled and total_time_running fields for a event.
+ */
+static void update_event_times(struct perf_event *event)
+{
+ struct perf_event_context *ctx = event->ctx;
+ u64 run_end;
+
+ if (event->state < PERF_EVENT_STATE_INACTIVE ||
+ event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
+ return;
+ /*
+ * in cgroup mode, time_enabled represents
+ * the time the event was enabled AND active
+ * tasks were in the monitored cgroup. This is
+ * independent of the activity of the context as
+ * there may be a mix of cgroup and non-cgroup events.
+ *
+ * That is why we treat cgroup events differently
+ * here.
+ */
+ if (is_cgroup_event(event))
+ run_end = perf_event_time(event);
+ else if (ctx->is_active)
+ run_end = ctx->time;
+ else
+ run_end = event->tstamp_stopped;
+
+ event->total_time_enabled = run_end - event->tstamp_enabled;
+
+ if (event->state == PERF_EVENT_STATE_INACTIVE)
+ run_end = event->tstamp_stopped;
+ else
+ run_end = perf_event_time(event);
+
+ event->total_time_running = run_end - event->tstamp_running;
+
+}
+
+/*
+ * Update total_time_enabled and total_time_running for all events in a group.
+ */
+static void update_group_times(struct perf_event *leader)
+{
+ struct perf_event *event;
+
+ update_event_times(leader);
+ list_for_each_entry(event, &leader->sibling_list, group_entry)
+ update_event_times(event);
+}
+
+static struct list_head *
+ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
+{
+ if (event->attr.pinned)
+ return &ctx->pinned_groups;
+ else
+ return &ctx->flexible_groups;
+}
+
+/*
+ * Add a event from the lists for its context.
+ * Must be called with ctx->mutex and ctx->lock held.
+ */
+static void
+list_add_event(struct perf_event *event, struct perf_event_context *ctx)
+{
+ WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
+ event->attach_state |= PERF_ATTACH_CONTEXT;
+
+ /*
+ * If we're a stand alone event or group leader, we go to the context
+ * list, group events are kept attached to the group so that
+ * perf_group_detach can, at all times, locate all siblings.
+ */
+ if (event->group_leader == event) {
+ struct list_head *list;
+
+ if (is_software_event(event))
+ event->group_flags |= PERF_GROUP_SOFTWARE;
+
+ list = ctx_group_list(event, ctx);
+ list_add_tail(&event->group_entry, list);
+ }
+
+ if (is_cgroup_event(event))
+ ctx->nr_cgroups++;
+
+ list_add_rcu(&event->event_entry, &ctx->event_list);
+ if (!ctx->nr_events)
+ perf_pmu_rotate_start(ctx->pmu);
+ ctx->nr_events++;
+ if (event->attr.inherit_stat)
+ ctx->nr_stat++;
+}
+
+/*
+ * Called at perf_event creation and when events are attached/detached from a
+ * group.
+ */
+static void perf_event__read_size(struct perf_event *event)
+{
+ int entry = sizeof(u64); /* value */
+ int size = 0;
+ int nr = 1;
+
+ if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
+ size += sizeof(u64);
+
+ if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
+ size += sizeof(u64);
+
+ if (event->attr.read_format & PERF_FORMAT_ID)
+ entry += sizeof(u64);
+
+ if (event->attr.read_format & PERF_FORMAT_GROUP) {
+ nr += event->group_leader->nr_siblings;
+ size += sizeof(u64);
+ }
+
+ size += entry * nr;
+ event->read_size = size;
+}
+
+static void perf_event__header_size(struct perf_event *event)
+{
+ struct perf_sample_data *data;
+ u64 sample_type = event->attr.sample_type;
+ u16 size = 0;
+
+ perf_event__read_size(event);
+
+ if (sample_type & PERF_SAMPLE_IP)
+ size += sizeof(data->ip);
+
+ if (sample_type & PERF_SAMPLE_ADDR)
+ size += sizeof(data->addr);
+
+ if (sample_type & PERF_SAMPLE_PERIOD)
+ size += sizeof(data->period);
+
+ if (sample_type & PERF_SAMPLE_READ)
+ size += event->read_size;
+
+ event->header_size = size;
+}
+
+static void perf_event__id_header_size(struct perf_event *event)
+{
+ struct perf_sample_data *data;
+ u64 sample_type = event->attr.sample_type;
+ u16 size = 0;
+
+ if (sample_type & PERF_SAMPLE_TID)
+ size += sizeof(data->tid_entry);
+
+ if (sample_type & PERF_SAMPLE_TIME)
+ size += sizeof(data->time);
+
+ if (sample_type & PERF_SAMPLE_ID)
+ size += sizeof(data->id);
+
+ if (sample_type & PERF_SAMPLE_STREAM_ID)
+ size += sizeof(data->stream_id);
+
+ if (sample_type & PERF_SAMPLE_CPU)
+ size += sizeof(data->cpu_entry);
+
+ event->id_header_size = size;
+}
+
+static void perf_group_attach(struct perf_event *event)
+{
+ struct perf_event *group_leader = event->group_leader, *pos;
+
+ /*
+ * We can have double attach due to group movement in perf_event_open.
+ */
+ if (event->attach_state & PERF_ATTACH_GROUP)
+ return;
+
+ event->attach_state |= PERF_ATTACH_GROUP;
+
+ if (group_leader == event)
+ return;
+
+ if (group_leader->group_flags & PERF_GROUP_SOFTWARE &&
+ !is_software_event(event))
+ group_leader->group_flags &= ~PERF_GROUP_SOFTWARE;
+
+ list_add_tail(&event->group_entry, &group_leader->sibling_list);
+ group_leader->nr_siblings++;
+
+ perf_event__header_size(group_leader);
+
+ list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
+ perf_event__header_size(pos);
+}
+
+/*
+ * Remove a event from the lists for its context.
+ * Must be called with ctx->mutex and ctx->lock held.
+ */
+static void
+list_del_event(struct perf_event *event, struct perf_event_context *ctx)
+{
+ struct perf_cpu_context *cpuctx;
+ /*
+ * We can have double detach due to exit/hot-unplug + close.
+ */
+ if (!(event->attach_state & PERF_ATTACH_CONTEXT))
+ return;
+
+ event->attach_state &= ~PERF_ATTACH_CONTEXT;
+
+ if (is_cgroup_event(event)) {
+ ctx->nr_cgroups--;
+ cpuctx = __get_cpu_context(ctx);
+ /*
+ * if there are no more cgroup events
+ * then cler cgrp to avoid stale pointer
+ * in update_cgrp_time_from_cpuctx()
+ */
+ if (!ctx->nr_cgroups)
+ cpuctx->cgrp = NULL;
+ }
+
+ ctx->nr_events--;
+ if (event->attr.inherit_stat)
+ ctx->nr_stat--;
+
+ list_del_rcu(&event->event_entry);
+
+ if (event->group_leader == event)
+ list_del_init(&event->group_entry);
+
+ update_group_times(event);
+
+ /*
+ * If event was in error state, then keep it
+ * that way, otherwise bogus counts will be
+ * returned on read(). The only way to get out
+ * of error state is by explicit re-enabling
+ * of the event
+ */
+ if (event->state > PERF_EVENT_STATE_OFF)
+ event->state = PERF_EVENT_STATE_OFF;
+}
+
+static void perf_group_detach(struct perf_event *event)
+{
+ struct perf_event *sibling, *tmp;
+ struct list_head *list = NULL;
+
+ /*
+ * We can have double detach due to exit/hot-unplug + close.
+ */
+ if (!(event->attach_state & PERF_ATTACH_GROUP))
+ return;
+
+ event->attach_state &= ~PERF_ATTACH_GROUP;
+
+ /*
+ * If this is a sibling, remove it from its group.
+ */
+ if (event->group_leader != event) {
+ list_del_init(&event->group_entry);
+ event->group_leader->nr_siblings--;
+ goto out;
+ }
+
+ if (!list_empty(&event->group_entry))
+ list = &event->group_entry;
+
+ /*
+ * If this was a group event with sibling events then
+ * upgrade the siblings to singleton events by adding them
+ * to whatever list we are on.
+ */
+ list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
+ if (list)
+ list_move_tail(&sibling->group_entry, list);
+ sibling->group_leader = sibling;
+
+ /* Inherit group flags from the previous leader */
+ sibling->group_flags = event->group_flags;
+ }
+
+out:
+ perf_event__header_size(event->group_leader);
+
+ list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
+ perf_event__header_size(tmp);
+}
+
+static inline int
+event_filter_match(struct perf_event *event)
+{
+ return (event->cpu == -1 || event->cpu == smp_processor_id())
+ && perf_cgroup_match(event);
+}
+
+static void
+event_sched_out(struct perf_event *event,
+ struct perf_cpu_context *cpuctx,
+ struct perf_event_context *ctx)
+{
+ u64 tstamp = perf_event_time(event);
+ u64 delta;
+ /*
+ * An event which could not be activated because of
+ * filter mismatch still needs to have its timings
+ * maintained, otherwise bogus information is return
+ * via read() for time_enabled, time_running:
+ */
+ if (event->state == PERF_EVENT_STATE_INACTIVE
+ && !event_filter_match(event)) {
+ delta = tstamp - event->tstamp_stopped;
+ event->tstamp_running += delta;
+ event->tstamp_stopped = tstamp;
+ }
+
+ if (event->state != PERF_EVENT_STATE_ACTIVE)
+ return;
+
+ event->state = PERF_EVENT_STATE_INACTIVE;
+ if (event->pending_disable) {
+ event->pending_disable = 0;
+ event->state = PERF_EVENT_STATE_OFF;
+ }
+ event->tstamp_stopped = tstamp;
+ event->pmu->del(event, 0);
+ event->oncpu = -1;
+
+ if (!is_software_event(event))
+ cpuctx->active_oncpu--;
+ ctx->nr_active--;
+ if (event->attr.exclusive || !cpuctx->active_oncpu)
+ cpuctx->exclusive = 0;
+}
+
+static void
+group_sched_out(struct perf_event *group_event,
+ struct perf_cpu_context *cpuctx,
+ struct perf_event_context *ctx)
+{
+ struct perf_event *event;
+ int state = group_event->state;
+
+ event_sched_out(group_event, cpuctx, ctx);
+
+ /*
+ * Schedule out siblings (if any):
+ */
+ list_for_each_entry(event, &group_event->sibling_list, group_entry)
+ event_sched_out(event, cpuctx, ctx);
+
+ if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
+ cpuctx->exclusive = 0;
+}
+
+/*
+ * Cross CPU call to remove a performance event
+ *
+ * We disable the event on the hardware level first. After that we
+ * remove it from the context list.
+ */
+static int __perf_remove_from_context(void *info)
+{
+ struct perf_event *event = info;
+ struct perf_event_context *ctx = event->ctx;
+ struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
+
+ raw_spin_lock(&ctx->lock);
+ event_sched_out(event, cpuctx, ctx);
+ list_del_event(event, ctx);
+ raw_spin_unlock(&ctx->lock);
+
+ return 0;
+}
+
+
+/*
+ * Remove the event from a task's (or a CPU's) list of events.
+ *
+ * CPU events are removed with a smp call. For task events we only
+ * call when the task is on a CPU.
+ *
+ * If event->ctx is a cloned context, callers must make sure that
+ * every task struct that event->ctx->task could possibly point to
+ * remains valid. This is OK when called from perf_release since
+ * that only calls us on the top-level context, which can't be a clone.
+ * When called from perf_event_exit_task, it's OK because the
+ * context has been detached from its task.
+ */
+static void perf_remove_from_context(struct perf_event *event)
+{
+ struct perf_event_context *ctx = event->ctx;
+ struct task_struct *task = ctx->task;
+
+ lockdep_assert_held(&ctx->mutex);
+
+ if (!task) {
+ /*
+ * Per cpu events are removed via an smp call and
+ * the removal is always successful.
+ */
+ cpu_function_call(event->cpu, __perf_remove_from_context, event);
+ return;
+ }
+
+retry:
+ if (!task_function_call(task, __perf_remove_from_context, event))
+ return;
+
+ raw_spin_lock_irq(&ctx->lock);
+ /*
+ * If we failed to find a running task, but find the context active now
+ * that we've acquired the ctx->lock, retry.
+ */
+ if (ctx->is_active) {
+ raw_spin_unlock_irq(&ctx->lock);
+ goto retry;
+ }
+
+ /*
+ * Since the task isn't running, its safe to remove the event, us
+ * holding the ctx->lock ensures the task won't get scheduled in.
+ */
+ list_del_event(event, ctx);
+ raw_spin_unlock_irq(&ctx->lock);
+}
+
+/*
+ * Cross CPU call to disable a performance event
+ */
+static int __perf_event_disable(void *info)
+{
+ struct perf_event *event = info;
+ struct perf_event_context *ctx = event->ctx;
+ struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
+
+ /*
+ * If this is a per-task event, need to check whether this
+ * event's task is the current task on this cpu.
+ *
+ * Can trigger due to concurrent perf_event_context_sched_out()
+ * flipping contexts around.
+ */
+ if (ctx->task && cpuctx->task_ctx != ctx)
+ return -EINVAL;
+
+ raw_spin_lock(&ctx->lock);
+
+ /*
+ * If the event is on, turn it off.
+ * If it is in error state, leave it in error state.
+ */
+ if (event->state >= PERF_EVENT_STATE_INACTIVE) {
+ update_context_time(ctx);
+ update_cgrp_time_from_event(event);
+ update_group_times(event);
+ if (event == event->group_leader)
+ group_sched_out(event, cpuctx, ctx);
+ else
+ event_sched_out(event, cpuctx, ctx);
+ event->state = PERF_EVENT_STATE_OFF;
+ }
+
+ raw_spin_unlock(&ctx->lock);
+
+ return 0;
+}
+
+/*
+ * Disable a event.
+ *
+ * If event->ctx is a cloned context, callers must make sure that
+ * every task struct that event->ctx->task could possibly point to
+ * remains valid. This condition is satisifed when called through
+ * perf_event_for_each_child or perf_event_for_each because they
+ * hold the top-level event's child_mutex, so any descendant that
+ * goes to exit will block in sync_child_event.
+ * When called from perf_pending_event it's OK because event->ctx
+ * is the current context on this CPU and preemption is disabled,
+ * hence we can't get into perf_event_task_sched_out for this context.
+ */
+void perf_event_disable(struct perf_event *event)
+{
+ struct perf_event_context *ctx = event->ctx;
+ struct task_struct *task = ctx->task;
+
+ if (!task) {
+ /*
+ * Disable the event on the cpu that it's on
+ */
+ cpu_function_call(event->cpu, __perf_event_disable, event);
+ return;
+ }
+
+retry:
+ if (!task_function_call(task, __perf_event_disable, event))
+ return;
+
+ raw_spin_lock_irq(&ctx->lock);
+ /*
+ * If the event is still active, we need to retry the cross-call.
+ */
+ if (event->state == PERF_EVENT_STATE_ACTIVE) {
+ raw_spin_unlock_irq(&ctx->lock);
+ /*
+ * Reload the task pointer, it might have been changed by
+ * a concurrent perf_event_context_sched_out().
+ */
+ task = ctx->task;
+ goto retry;
+ }
+
+ /*
+ * Since we have the lock this context can't be scheduled
+ * in, so we can change the state safely.
+ */
+ if (event->state == PERF_EVENT_STATE_INACTIVE) {
+ update_group_times(event);
+ event->state = PERF_EVENT_STATE_OFF;
+ }
+ raw_spin_unlock_irq(&ctx->lock);
+}
+
+static void perf_set_shadow_time(struct perf_event *event,
+ struct perf_event_context *ctx,
+ u64 tstamp)
+{
+ /*
+ * use the correct time source for the time snapshot
+ *
+ * We could get by without this by leveraging the
+ * fact that to get to this function, the caller
+ * has most likely already called update_context_time()
+ * and update_cgrp_time_xx() and thus both timestamp
+ * are identical (or very close). Given that tstamp is,
+ * already adjusted for cgroup, we could say that:
+ * tstamp - ctx->timestamp
+ * is equivalent to
+ * tstamp - cgrp->timestamp.
+ *
+ * Then, in perf_output_read(), the calculation would
+ * work with no changes because:
+ * - event is guaranteed scheduled in
+ * - no scheduled out in between
+ * - thus the timestamp would be the same
+ *
+ * But this is a bit hairy.
+ *
+ * So instead, we have an explicit cgroup call to remain
+ * within the time time source all along. We believe it
+ * is cleaner and simpler to understand.
+ */
+ if (is_cgroup_event(event))
+ perf_cgroup_set_shadow_time(event, tstamp);
+ else
+ event->shadow_ctx_time = tstamp - ctx->timestamp;
+}
+
+#define MAX_INTERRUPTS (~0ULL)
+
+static void perf_log_throttle(struct perf_event *event, int enable);
+
+static int
+event_sched_in(struct perf_event *event,
+ struct perf_cpu_context *cpuctx,
+ struct perf_event_context *ctx)
+{
+ u64 tstamp = perf_event_time(event);
+
+ if (event->state <= PERF_EVENT_STATE_OFF)
+ return 0;
+
+ event->state = PERF_EVENT_STATE_ACTIVE;
+ event->oncpu = smp_processor_id();
+
+ /*
+ * Unthrottle events, since we scheduled we might have missed several
+ * ticks already, also for a heavily scheduling task there is little
+ * guarantee it'll get a tick in a timely manner.
+ */
+ if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
+ perf_log_throttle(event, 1);
+ event->hw.interrupts = 0;
+ }
+
+ /*
+ * The new state must be visible before we turn it on in the hardware:
+ */
+ smp_wmb();
+
+ if (event->pmu->add(event, PERF_EF_START)) {
+ event->state = PERF_EVENT_STATE_INACTIVE;
+ event->oncpu = -1;
+ return -EAGAIN;
+ }
+
+ event->tstamp_running += tstamp - event->tstamp_stopped;
+
+ perf_set_shadow_time(event, ctx, tstamp);
+
+ if (!is_software_event(event))
+ cpuctx->active_oncpu++;
+ ctx->nr_active++;
+
+ if (event->attr.exclusive)
+ cpuctx->exclusive = 1;
+
+ return 0;
+}
+
+static int
+group_sched_in(struct perf_event *group_event,
+ struct perf_cpu_context *cpuctx,
+ struct perf_event_context *ctx)
+{
+ struct perf_event *event, *partial_group = NULL;
+ struct pmu *pmu = group_event->pmu;
+ u64 now = ctx->time;
+ bool simulate = false;
+
+ if (group_event->state == PERF_EVENT_STATE_OFF)
+ return 0;
+
+ pmu->start_txn(pmu);
+
+ if (event_sched_in(group_event, cpuctx, ctx)) {
+ pmu->cancel_txn(pmu);
+ return -EAGAIN;
+ }
+
+ /*
+ * Schedule in siblings as one group (if any):
+ */
+ list_for_each_entry(event, &group_event->sibling_list, group_entry) {
+ if (event_sched_in(event, cpuctx, ctx)) {
+ partial_group = event;
+ goto group_error;
+ }
+ }
+
+ if (!pmu->commit_txn(pmu))
+ return 0;
+
+group_error:
+ /*
+ * Groups can be scheduled in as one unit only, so undo any
+ * partial group before returning:
+ * The events up to the failed event are scheduled out normally,
+ * tstamp_stopped will be updated.
+ *
+ * The failed events and the remaining siblings need to have
+ * their timings updated as if they had gone thru event_sched_in()
+ * and event_sched_out(). This is required to get consistent timings
+ * across the group. This also takes care of the case where the group
+ * could never be scheduled by ensuring tstamp_stopped is set to mark
+ * the time the event was actually stopped, such that time delta
+ * calculation in update_event_times() is correct.
+ */
+ list_for_each_entry(event, &group_event->sibling_list, group_entry) {
+ if (event == partial_group)
+ simulate = true;
+
+ if (simulate) {
+ event->tstamp_running += now - event->tstamp_stopped;
+ event->tstamp_stopped = now;
+ } else {
+ event_sched_out(event, cpuctx, ctx);
+ }
+ }
+ event_sched_out(group_event, cpuctx, ctx);
+
+ pmu->cancel_txn(pmu);
+
+ return -EAGAIN;
+}
+
+/*
+ * Work out whether we can put this event group on the CPU now.
+ */
+static int group_can_go_on(struct perf_event *event,
+ struct perf_cpu_context *cpuctx,
+ int can_add_hw)
+{
+ /*
+ * Groups consisting entirely of software events can always go on.
+ */
+ if (event->group_flags & PERF_GROUP_SOFTWARE)
+ return 1;
+ /*
+ * If an exclusive group is already on, no other hardware
+ * events can go on.
+ */
+ if (cpuctx->exclusive)
+ return 0;
+ /*
+ * If this group is exclusive and there are already
+ * events on the CPU, it can't go on.
+ */
+ if (event->attr.exclusive && cpuctx->active_oncpu)
+ return 0;
+ /*
+ * Otherwise, try to add it if all previous groups were able
+ * to go on.
+ */
+ return can_add_hw;
+}
+
+static void add_event_to_ctx(struct perf_event *event,
+ struct perf_event_context *ctx)
+{
+ u64 tstamp = perf_event_time(event);
+
+ list_add_event(event, ctx);
+ perf_group_attach(event);
+ event->tstamp_enabled = tstamp;
+ event->tstamp_running = tstamp;
+ event->tstamp_stopped = tstamp;
+}
+
+static void perf_event_context_sched_in(struct perf_event_context *ctx,
+ struct task_struct *tsk);
+
+/*
+ * Cross CPU call to install and enable a performance event
+ *
+ * Must be called with ctx->mutex held
+ */
+static int __perf_install_in_context(void *info)
+{
+ struct perf_event *event = info;
+ struct perf_event_context *ctx = event->ctx;
+ struct perf_event *leader = event->group_leader;
+ struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
+ int err;
+
+ /*
+ * In case we're installing a new context to an already running task,
+ * could also happen before perf_event_task_sched_in() on architectures
+ * which do context switches with IRQs enabled.
+ */
+ if (ctx->task && !cpuctx->task_ctx)
+ perf_event_context_sched_in(ctx, ctx->task);
+
+ raw_spin_lock(&ctx->lock);
+ ctx->is_active = 1;
+ update_context_time(ctx);
+ /*
+ * update cgrp time only if current cgrp
+ * matches event->cgrp. Must be done before
+ * calling add_event_to_ctx()
+ */
+ update_cgrp_time_from_event(event);
+
+ add_event_to_ctx(event, ctx);
+
+ if (!event_filter_match(event))
+ goto unlock;
+
+ /*
+ * Don't put the event on if it is disabled or if
+ * it is in a group and the group isn't on.
+ */
+ if (event->state != PERF_EVENT_STATE_INACTIVE ||
+ (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE))
+ goto unlock;
+
+ /*
+ * An exclusive event can't go on if there are already active
+ * hardware events, and no hardware event can go on if there
+ * is already an exclusive event on.
+ */
+ if (!group_can_go_on(event, cpuctx, 1))
+ err = -EEXIST;
+ else
+ err = event_sched_in(event, cpuctx, ctx);
+
+ if (err) {
+ /*
+ * This event couldn't go on. If it is in a group
+ * then we have to pull the whole group off.
+ * If the event group is pinned then put it in error state.
+ */
+ if (leader != event)
+ group_sched_out(leader, cpuctx, ctx);
+ if (leader->attr.pinned) {
+ update_group_times(leader);
+ leader->state = PERF_EVENT_STATE_ERROR;
+ }
+ }
+
+unlock:
+ raw_spin_unlock(&ctx->lock);
+
+ return 0;
+}
+
+/*
+ * Attach a performance event to a context
+ *
+ * First we add the event to the list with the hardware enable bit
+ * in event->hw_config cleared.
+ *
+ * If the event is attached to a task which is on a CPU we use a smp
+ * call to enable it in the task context. The task might have been
+ * scheduled away, but we check this in the smp call again.
+ */
+static void
+perf_install_in_context(struct perf_event_context *ctx,
+ struct perf_event *event,
+ int cpu)
+{
+ struct task_struct *task = ctx->task;
+
+ lockdep_assert_held(&ctx->mutex);
+
+ event->ctx = ctx;
+
+ if (!task) {
+ /*
+ * Per cpu events are installed via an smp call and
+ * the install is always successful.
+ */
+ cpu_function_call(cpu, __perf_install_in_context, event);
+ return;
+ }
+
+retry:
+ if (!task_function_call(task, __perf_install_in_context, event))
+ return;
+
+ raw_spin_lock_irq(&ctx->lock);
+ /*
+ * If we failed to find a running task, but find the context active now
+ * that we've acquired the ctx->lock, retry.
+ */
+ if (ctx->is_active) {
+ raw_spin_unlock_irq(&ctx->lock);
+ goto retry;
+ }
+
+ /*
+ * Since the task isn't running, its safe to add the event, us holding
+ * the ctx->lock ensures the task won't get scheduled in.
+ */
+ add_event_to_ctx(event, ctx);
+ raw_spin_unlock_irq(&ctx->lock);
+}
+
+/*
+ * Put a event into inactive state and update time fields.
+ * Enabling the leader of a group effectively enables all
+ * the group members that aren't explicitly disabled, so we
+ * have to update their ->tstamp_enabled also.
+ * Note: this works for group members as well as group leaders
+ * since the non-leader members' sibling_lists will be empty.
+ */
+static void __perf_event_mark_enabled(struct perf_event *event,
+ struct perf_event_context *ctx)
+{
+ struct perf_event *sub;
+ u64 tstamp = perf_event_time(event);
+
+ event->state = PERF_EVENT_STATE_INACTIVE;
+ event->tstamp_enabled = tstamp - event->total_time_enabled;
+ list_for_each_entry(sub, &event->sibling_list, group_entry) {
+ if (sub->state >= PERF_EVENT_STATE_INACTIVE)
+ sub->tstamp_enabled = tstamp - sub->total_time_enabled;
+ }
+}
+
+/*
+ * Cross CPU call to enable a performance event
+ */
+static int __perf_event_enable(void *info)
+{
+ struct perf_event *event = info;
+ struct perf_event_context *ctx = event->ctx;
+ struct perf_event *leader = event->group_leader;
+ struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
+ int err;
+
+ if (WARN_ON_ONCE(!ctx->is_active))
+ return -EINVAL;
+
+ raw_spin_lock(&ctx->lock);
+ update_context_time(ctx);
+
+ if (event->state >= PERF_EVENT_STATE_INACTIVE)
+ goto unlock;
+
+ /*
+ * set current task's cgroup time reference point
+ */
+ perf_cgroup_set_timestamp(current, ctx);
+
+ __perf_event_mark_enabled(event, ctx);
+
+ if (!event_filter_match(event)) {
+ if (is_cgroup_event(event))
+ perf_cgroup_defer_enabled(event);
+ goto unlock;
+ }
+
+ /*
+ * If the event is in a group and isn't the group leader,
+ * then don't put it on unless the group is on.
+ */
+ if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)
+ goto unlock;
+
+ if (!group_can_go_on(event, cpuctx, 1)) {
+ err = -EEXIST;
+ } else {
+ if (event == leader)
+ err = group_sched_in(event, cpuctx, ctx);
+ else
+ err = event_sched_in(event, cpuctx, ctx);
+ }
+
+ if (err) {
+ /*
+ * If this event can't go on and it's part of a
+ * group, then the whole group has to come off.
+ */
+ if (leader != event)
+ group_sched_out(leader, cpuctx, ctx);
+ if (leader->attr.pinned) {
+ update_group_times(leader);
+ leader->state = PERF_EVENT_STATE_ERROR;
+ }
+ }
+
+unlock:
+ raw_spin_unlock(&ctx->lock);
+
+ return 0;
+}
+
+/*
+ * Enable a event.
+ *
+ * If event->ctx is a cloned context, callers must make sure that
+ * every task struct that event->ctx->task could possibly point to
+ * remains valid. This condition is satisfied when called through
+ * perf_event_for_each_child or perf_event_for_each as described
+ * for perf_event_disable.
+ */
+void perf_event_enable(struct perf_event *event)
+{
+ struct perf_event_context *ctx = event->ctx;
+ struct task_struct *task = ctx->task;
+
+ if (!task) {
+ /*
+ * Enable the event on the cpu that it's on
+ */
+ cpu_function_call(event->cpu, __perf_event_enable, event);
+ return;
+ }
+
+ raw_spin_lock_irq(&ctx->lock);
+ if (event->state >= PERF_EVENT_STATE_INACTIVE)
+ goto out;
+
+ /*
+ * If the event is in error state, clear that first.
+ * That way, if we see the event in error state below, we
+ * know that it has gone back into error state, as distinct
+ * from the task having been scheduled away before the
+ * cross-call arrived.
+ */
+ if (event->state == PERF_EVENT_STATE_ERROR)
+ event->state = PERF_EVENT_STATE_OFF;
+
+retry:
+ if (!ctx->is_active) {
+ __perf_event_mark_enabled(event, ctx);
+ goto out;
+ }
+
+ raw_spin_unlock_irq(&ctx->lock);
+
+ if (!task_function_call(task, __perf_event_enable, event))
+ return;
+
+ raw_spin_lock_irq(&ctx->lock);
+
+ /*
+ * If the context is active and the event is still off,
+ * we need to retry the cross-call.
+ */
+ if (ctx->is_active && event->state == PERF_EVENT_STATE_OFF) {
+ /*
+ * task could have been flipped by a concurrent
+ * perf_event_context_sched_out()
+ */
+ task = ctx->task;
+ goto retry;
+ }
+
+out:
+ raw_spin_unlock_irq(&ctx->lock);
+}
+
+static int perf_event_refresh(struct perf_event *event, int refresh)
+{
+ /*
+ * not supported on inherited events
+ */
+ if (event->attr.inherit || !is_sampling_event(event))
+ return -EINVAL;
+
+ atomic_add(refresh, &event->event_limit);
+ perf_event_enable(event);
+
+ return 0;
+}
+
+static void ctx_sched_out(struct perf_event_context *ctx,
+ struct perf_cpu_context *cpuctx,
+ enum event_type_t event_type)
+{
+ struct perf_event *event;
+
+ raw_spin_lock(&ctx->lock);
+ perf_pmu_disable(ctx->pmu);
+ ctx->is_active = 0;
+ if (likely(!ctx->nr_events))
+ goto out;
+ update_context_time(ctx);
+ update_cgrp_time_from_cpuctx(cpuctx);
+
+ if (!ctx->nr_active)
+ goto out;
+
+ if (event_type & EVENT_PINNED) {
+ list_for_each_entry(event, &ctx->pinned_groups, group_entry)
+ group_sched_out(event, cpuctx, ctx);
+ }
+
+ if (event_type & EVENT_FLEXIBLE) {
+ list_for_each_entry(event, &ctx->flexible_groups, group_entry)
+ group_sched_out(event, cpuctx, ctx);
+ }
+out:
+ perf_pmu_enable(ctx->pmu);
+ raw_spin_unlock(&ctx->lock);
+}
+
+/*
+ * Test whether two contexts are equivalent, i.e. whether they
+ * have both been cloned from the same version of the same context
+ * and they both have the same number of enabled events.
+ * If the number of enabled events is the same, then the set
+ * of enabled events should be the same, because these are both
+ * inherited contexts, therefore we can't access individual events
+ * in them directly with an fd; we can only enable/disable all
+ * events via prctl, or enable/disable all events in a family
+ * via ioctl, which will have the same effect on both contexts.
+ */
+static int context_equiv(struct perf_event_context *ctx1,
+ struct perf_event_context *ctx2)
+{
+ return ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx
+ && ctx1->parent_gen == ctx2->parent_gen
+ && !ctx1->pin_count && !ctx2->pin_count;
+}
+
+static void __perf_event_sync_stat(struct perf_event *event,
+ struct perf_event *next_event)
+{
+ u64 value;
+
+ if (!event->attr.inherit_stat)
+ return;
+
+ /*
+ * Update the event value, we cannot use perf_event_read()
+ * because we're in the middle of a context switch and have IRQs
+ * disabled, which upsets smp_call_function_single(), however
+ * we know the event must be on the current CPU, therefore we
+ * don't need to use it.
+ */
+ switch (event->state) {
+ case PERF_EVENT_STATE_ACTIVE:
+ event->pmu->read(event);
+ /* fall-through */
+
+ case PERF_EVENT_STATE_INACTIVE:
+ update_event_times(event);
+ break;
+
+ default:
+ break;
+ }
+
+ /*
+ * In order to keep per-task stats reliable we need to flip the event
+ * values when we flip the contexts.
+ */
+ value = local64_read(&next_event->count);
+ value = local64_xchg(&event->count, value);
+ local64_set(&next_event->count, value);
+
+ swap(event->total_time_enabled, next_event->total_time_enabled);
+ swap(event->total_time_running, next_event->total_time_running);
+
+ /*
+ * Since we swizzled the values, update the user visible data too.
+ */
+ perf_event_update_userpage(event);
+ perf_event_update_userpage(next_event);
+}
+
+#define list_next_entry(pos, member) \
+ list_entry(pos->member.next, typeof(*pos), member)
+
+static void perf_event_sync_stat(struct perf_event_context *ctx,
+ struct perf_event_context *next_ctx)
+{
+ struct perf_event *event, *next_event;
+
+ if (!ctx->nr_stat)
+ return;
+
+ update_context_time(ctx);
+
+ event = list_first_entry(&ctx->event_list,
+ struct perf_event, event_entry);
+
+ next_event = list_first_entry(&next_ctx->event_list,
+ struct perf_event, event_entry);
+
+ while (&event->event_entry != &ctx->event_list &&
+ &next_event->event_entry != &next_ctx->event_list) {
+
+ __perf_event_sync_stat(event, next_event);
+
+ event = list_next_entry(event, event_entry);
+ next_event = list_next_entry(next_event, event_entry);
+ }
+}
+
+static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
+ struct task_struct *next)
+{
+ struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
+ struct perf_event_context *next_ctx;
+ struct perf_event_context *parent;
+ struct perf_cpu_context *cpuctx;
+ int do_switch = 1;
+
+ if (likely(!ctx))
+ return;
+
+ cpuctx = __get_cpu_context(ctx);
+ if (!cpuctx->task_ctx)
+ return;
+
+ rcu_read_lock();
+ parent = rcu_dereference(ctx->parent_ctx);
+ next_ctx = next->perf_event_ctxp[ctxn];
+ if (parent && next_ctx &&
+ rcu_dereference(next_ctx->parent_ctx) == parent) {
+ /*
+ * Looks like the two contexts are clones, so we might be
+ * able to optimize the context switch. We lock both
+ * contexts and check that they are clones under the
+ * lock (including re-checking that neither has been
+ * uncloned in the meantime). It doesn't matter which
+ * order we take the locks because no other cpu could
+ * be trying to lock both of these tasks.
+ */
+ raw_spin_lock(&ctx->lock);
+ raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
+ if (context_equiv(ctx, next_ctx)) {
+ /*
+ * XXX do we need a memory barrier of sorts
+ * wrt to rcu_dereference() of perf_event_ctxp
+ */
+ task->perf_event_ctxp[ctxn] = next_ctx;
+ next->perf_event_ctxp[ctxn] = ctx;
+ ctx->task = next;
+ next_ctx->task = task;
+ do_switch = 0;
+
+ perf_event_sync_stat(ctx, next_ctx);
+ }
+ raw_spin_unlock(&next_ctx->lock);
+ raw_spin_unlock(&ctx->lock);
+ }
+ rcu_read_unlock();
+
+ if (do_switch) {
+ ctx_sched_out(ctx, cpuctx, EVENT_ALL);
+ cpuctx->task_ctx = NULL;
+ }
+}
+
+#define for_each_task_context_nr(ctxn) \
+ for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
+
+/*
+ * Called from scheduler to remove the events of the current task,
+ * with interrupts disabled.
+ *
+ * We stop each event and update the event value in event->count.
+ *
+ * This does not protect us against NMI, but disable()
+ * sets the disabled bit in the control field of event _before_
+ * accessing the event control register. If a NMI hits, then it will
+ * not restart the event.
+ */
+void __perf_event_task_sched_out(struct task_struct *task,
+ struct task_struct *next)
+{
+ int ctxn;
+
+ for_each_task_context_nr(ctxn)
+ perf_event_context_sched_out(task, ctxn, next);
+
+ /*
+ * if cgroup events exist on this CPU, then we need
+ * to check if we have to switch out PMU state.
+ * cgroup event are system-wide mode only
+ */
+ if (atomic_read(&__get_cpu_var(perf_cgroup_events)))
+ perf_cgroup_sched_out(task);
+}
+
+static void task_ctx_sched_out(struct perf_event_context *ctx,
+ enum event_type_t event_type)
+{
+ struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
+
+ if (!cpuctx->task_ctx)
+ return;
+
+ if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
+ return;
+
+ ctx_sched_out(ctx, cpuctx, event_type);
+ cpuctx->task_ctx = NULL;
+}
+
+/*
+ * Called with IRQs disabled
+ */
+static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
+ enum event_type_t event_type)
+{
+ ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
+}
+
+static void
+ctx_pinned_sched_in(struct perf_event_context *ctx,
+ struct perf_cpu_context *cpuctx)
+{
+ struct perf_event *event;
+
+ list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
+ if (event->state <= PERF_EVENT_STATE_OFF)
+ continue;
+ if (!event_filter_match(event))
+ continue;
+
+ /* may need to reset tstamp_enabled */
+ if (is_cgroup_event(event))
+ perf_cgroup_mark_enabled(event, ctx);
+
+ if (group_can_go_on(event, cpuctx, 1))
+ group_sched_in(event, cpuctx, ctx);
+
+ /*
+ * If this pinned group hasn't been scheduled,
+ * put it in error state.
+ */
+ if (event->state == PERF_EVENT_STATE_INACTIVE) {
+ update_group_times(event);
+ event->state = PERF_EVENT_STATE_ERROR;
+ }
+ }
+}
+
+static void
+ctx_flexible_sched_in(struct perf_event_context *ctx,
+ struct perf_cpu_context *cpuctx)
+{
+ struct perf_event *event;
+ int can_add_hw = 1;
+
+ list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
+ /* Ignore events in OFF or ERROR state */
+ if (event->state <= PERF_EVENT_STATE_OFF)
+ continue;
+ /*
+ * Listen to the 'cpu' scheduling filter constraint
+ * of events:
+ */
+ if (!event_filter_match(event))
+ continue;
+
+ /* may need to reset tstamp_enabled */
+ if (is_cgroup_event(event))
+ perf_cgroup_mark_enabled(event, ctx);
+
+ if (group_can_go_on(event, cpuctx, can_add_hw)) {
+ if (group_sched_in(event, cpuctx, ctx))
+ can_add_hw = 0;
+ }
+ }
+}
+
+static void
+ctx_sched_in(struct perf_event_context *ctx,
+ struct perf_cpu_context *cpuctx,
+ enum event_type_t event_type,
+ struct task_struct *task)
+{
+ u64 now;
+
+ raw_spin_lock(&ctx->lock);
+ ctx->is_active = 1;
+ if (likely(!ctx->nr_events))
+ goto out;
+
+ now = perf_clock();
+ ctx->timestamp = now;
+ perf_cgroup_set_timestamp(task, ctx);
+ /*
+ * First go through the list and put on any pinned groups
+ * in order to give them the best chance of going on.
+ */
+ if (event_type & EVENT_PINNED)
+ ctx_pinned_sched_in(ctx, cpuctx);
+
+ /* Then walk through the lower prio flexible groups */
+ if (event_type & EVENT_FLEXIBLE)
+ ctx_flexible_sched_in(ctx, cpuctx);
+
+out:
+ raw_spin_unlock(&ctx->lock);
+}
+
+static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
+ enum event_type_t event_type,
+ struct task_struct *task)
+{
+ struct perf_event_context *ctx = &cpuctx->ctx;
+
+ ctx_sched_in(ctx, cpuctx, event_type, task);
+}
+
+static void task_ctx_sched_in(struct perf_event_context *ctx,
+ enum event_type_t event_type)
+{
+ struct perf_cpu_context *cpuctx;
+
+ cpuctx = __get_cpu_context(ctx);
+ if (cpuctx->task_ctx == ctx)
+ return;
+
+ ctx_sched_in(ctx, cpuctx, event_type, NULL);
+ cpuctx->task_ctx = ctx;
+}
+
+static void perf_event_context_sched_in(struct perf_event_context *ctx,
+ struct task_struct *task)
+{
+ struct perf_cpu_context *cpuctx;
+
+ cpuctx = __get_cpu_context(ctx);
+ if (cpuctx->task_ctx == ctx)
+ return;
+
+ perf_pmu_disable(ctx->pmu);
+ /*
+ * We want to keep the following priority order:
+ * cpu pinned (that don't need to move), task pinned,
+ * cpu flexible, task flexible.
+ */
+ cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
+
+ ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
+ cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
+ ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
+
+ cpuctx->task_ctx = ctx;
+
+ /*
+ * Since these rotations are per-cpu, we need to ensure the
+ * cpu-context we got scheduled on is actually rotating.
+ */
+ perf_pmu_rotate_start(ctx->pmu);
+ perf_pmu_enable(ctx->pmu);
+}
+
+/*
+ * Called from scheduler to add the events of the current task
+ * with interrupts disabled.
+ *
+ * We restore the event value and then enable it.
+ *
+ * This does not protect us against NMI, but enable()
+ * sets the enabled bit in the control field of event _before_
+ * accessing the event control register. If a NMI hits, then it will
+ * keep the event running.
+ */
+void __perf_event_task_sched_in(struct task_struct *task)
+{
+ struct perf_event_context *ctx;
+ int ctxn;
+
+ for_each_task_context_nr(ctxn) {
+ ctx = task->perf_event_ctxp[ctxn];
+ if (likely(!ctx))
+ continue;
+
+ perf_event_context_sched_in(ctx, task);
+ }
+ /*
+ * if cgroup events exist on this CPU, then we need
+ * to check if we have to switch in PMU state.
+ * cgroup event are system-wide mode only
+ */
+ if (atomic_read(&__get_cpu_var(perf_cgroup_events)))
+ perf_cgroup_sched_in(task);
+}
+
+static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
+{
+ u64 frequency = event->attr.sample_freq;
+ u64 sec = NSEC_PER_SEC;
+ u64 divisor, dividend;
+
+ int count_fls, nsec_fls, frequency_fls, sec_fls;
+
+ count_fls = fls64(count);
+ nsec_fls = fls64(nsec);
+ frequency_fls = fls64(frequency);
+ sec_fls = 30;
+
+ /*
+ * We got @count in @nsec, with a target of sample_freq HZ
+ * the target period becomes:
+ *
+ * @count * 10^9
+ * period = -------------------
+ * @nsec * sample_freq
+ *
+ */
+
+ /*
+ * Reduce accuracy by one bit such that @a and @b converge
+ * to a similar magnitude.
+ */
+#define REDUCE_FLS(a, b) \
+do { \
+ if (a##_fls > b##_fls) { \
+ a >>= 1; \
+ a##_fls--; \
+ } else { \
+ b >>= 1; \
+ b##_fls--; \
+ } \
+} while (0)
+
+ /*
+ * Reduce accuracy until either term fits in a u64, then proceed with
+ * the other, so that finally we can do a u64/u64 division.
+ */
+ while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
+ REDUCE_FLS(nsec, frequency);
+ REDUCE_FLS(sec, count);
+ }
+
+ if (count_fls + sec_fls > 64) {
+ divisor = nsec * frequency;
+
+ while (count_fls + sec_fls > 64) {
+ REDUCE_FLS(count, sec);
+ divisor >>= 1;
+ }
+
+ dividend = count * sec;
+ } else {
+ dividend = count * sec;
+
+ while (nsec_fls + frequency_fls > 64) {
+ REDUCE_FLS(nsec, frequency);
+ dividend >>= 1;
+ }
+
+ divisor = nsec * frequency;
+ }
+
+ if (!divisor)
+ return dividend;
+
+ return div64_u64(dividend, divisor);
+}
+
+static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count)
+{
+ struct hw_perf_event *hwc = &event->hw;
+ s64 period, sample_period;
+ s64 delta;
+
+ period = perf_calculate_period(event, nsec, count);
+
+ delta = (s64)(period - hwc->sample_period);
+ delta = (delta + 7) / 8; /* low pass filter */
+
+ sample_period = hwc->sample_period + delta;
+
+ if (!sample_period)
+ sample_period = 1;
+
+ hwc->sample_period = sample_period;
+
+ if (local64_read(&hwc->period_left) > 8*sample_period) {
+ event->pmu->stop(event, PERF_EF_UPDATE);
+ local64_set(&hwc->period_left, 0);
+ event->pmu->start(event, PERF_EF_RELOAD);
+ }
+}
+
+static void perf_ctx_adjust_freq(struct perf_event_context *ctx, u64 period)
+{
+ struct perf_event *event;
+ struct hw_perf_event *hwc;
+ u64 interrupts, now;
+ s64 delta;
+
+ raw_spin_lock(&ctx->lock);
+ list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
+ if (event->state != PERF_EVENT_STATE_ACTIVE)
+ continue;
+
+ if (!event_filter_match(event))
+ continue;
+
+ hwc = &event->hw;
+
+ interrupts = hwc->interrupts;
+ hwc->interrupts = 0;
+
+ /*
+ * unthrottle events on the tick
+ */
+ if (interrupts == MAX_INTERRUPTS) {
+ perf_log_throttle(event, 1);
+ event->pmu->start(event, 0);
+ }
+
+ if (!event->attr.freq || !event->attr.sample_freq)
+ continue;
+
+ event->pmu->read(event);
+ now = local64_read(&event->count);
+ delta = now - hwc->freq_count_stamp;
+ hwc->freq_count_stamp = now;
+
+ if (delta > 0)
+ perf_adjust_period(event, period, delta);
+ }
+ raw_spin_unlock(&ctx->lock);
+}
+
+/*
+ * Round-robin a context's events:
+ */
+static void rotate_ctx(struct perf_event_context *ctx)
+{
+ raw_spin_lock(&ctx->lock);
+
+ /*
+ * 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);
+}
+
+/*
+ * perf_pmu_rotate_start() and perf_rotate_context() are fully serialized
+ * because they're strictly cpu affine and rotate_start is called with IRQs
+ * disabled, while rotate_context is called from IRQ context.
+ */
+static void perf_rotate_context(struct perf_cpu_context *cpuctx)
+{
+ u64 interval = (u64)cpuctx->jiffies_interval * TICK_NSEC;
+ struct perf_event_context *ctx = NULL;
+ int rotate = 0, remove = 1;
+
+ if (cpuctx->ctx.nr_events) {
+ remove = 0;
+ if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
+ rotate = 1;
+ }
+
+ ctx = cpuctx->task_ctx;
+ if (ctx && ctx->nr_events) {
+ remove = 0;
+ if (ctx->nr_events != ctx->nr_active)
+ rotate = 1;
+ }
+
+ perf_pmu_disable(cpuctx->ctx.pmu);
+ perf_ctx_adjust_freq(&cpuctx->ctx, interval);
+ if (ctx)
+ perf_ctx_adjust_freq(ctx, interval);
+
+ if (!rotate)
+ goto done;
+
+ cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
+ if (ctx)
+ task_ctx_sched_out(ctx, EVENT_FLEXIBLE);
+
+ rotate_ctx(&cpuctx->ctx);
+ if (ctx)
+ rotate_ctx(ctx);
+
+ cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, current);
+ if (ctx)
+ task_ctx_sched_in(ctx, EVENT_FLEXIBLE);
+
+done:
+ if (remove)
+ list_del_init(&cpuctx->rotation_list);
+
+ perf_pmu_enable(cpuctx->ctx.pmu);
+}
+
+void perf_event_task_tick(void)
+{
+ struct list_head *head = &__get_cpu_var(rotation_list);
+ struct perf_cpu_context *cpuctx, *tmp;
+
+ WARN_ON(!irqs_disabled());
+
+ list_for_each_entry_safe(cpuctx, tmp, head, rotation_list) {
+ if (cpuctx->jiffies_interval == 1 ||
+ !(jiffies % cpuctx->jiffies_interval))
+ perf_rotate_context(cpuctx);
+ }
+}
+
+static int event_enable_on_exec(struct perf_event *event,
+ struct perf_event_context *ctx)
+{
+ if (!event->attr.enable_on_exec)
+ return 0;
+
+ event->attr.enable_on_exec = 0;
+ if (event->state >= PERF_EVENT_STATE_INACTIVE)
+ return 0;
+
+ __perf_event_mark_enabled(event, ctx);
+
+ return 1;
+}
+
+/*
+ * Enable all of a task's events that have been marked enable-on-exec.
+ * This expects task == current.
+ */
+static void perf_event_enable_on_exec(struct perf_event_context *ctx)
+{
+ struct perf_event *event;
+ unsigned long flags;
+ int enabled = 0;
+ int ret;
+
+ local_irq_save(flags);
+ if (!ctx || !ctx->nr_events)
+ goto out;
+
+ /*
+ * We must ctxsw out cgroup events to avoid conflict
+ * when invoking perf_task_event_sched_in() later on
+ * in this function. Otherwise we end up trying to
+ * ctxswin cgroup events which are already scheduled
+ * in.
+ */
+ perf_cgroup_sched_out(current);
+ task_ctx_sched_out(ctx, EVENT_ALL);
+
+ raw_spin_lock(&ctx->lock);
+
+ list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
+ ret = event_enable_on_exec(event, ctx);
+ if (ret)
+ enabled = 1;
+ }
+
+ list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
+ ret = event_enable_on_exec(event, ctx);
+ if (ret)
+ enabled = 1;
+ }
+
+ /*
+ * Unclone this context if we enabled any event.
+ */
+ if (enabled)
+ unclone_ctx(ctx);
+
+ raw_spin_unlock(&ctx->lock);
+
+ /*
+ * Also calls ctxswin for cgroup events, if any:
+ */
+ perf_event_context_sched_in(ctx, ctx->task);
+out:
+ local_irq_restore(flags);
+}
+
+/*
+ * Cross CPU call to read the hardware event
+ */
+static void __perf_event_read(void *info)
+{
+ struct perf_event *event = info;
+ struct perf_event_context *ctx = event->ctx;
+ struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
+
+ /*
+ * If this is a task context, we need to check whether it is
+ * the current task context of this cpu. If not it has been
+ * scheduled out before the smp call arrived. In that case
+ * event->count would have been updated to a recent sample
+ * when the event was scheduled out.
+ */
+ if (ctx->task && cpuctx->task_ctx != ctx)
+ return;
+
+ raw_spin_lock(&ctx->lock);
+ if (ctx->is_active) {
+ update_context_time(ctx);
+ update_cgrp_time_from_event(event);
+ }
+ update_event_times(event);
+ if (event->state == PERF_EVENT_STATE_ACTIVE)
+ event->pmu->read(event);
+ raw_spin_unlock(&ctx->lock);
+}
+
+static inline u64 perf_event_count(struct perf_event *event)
+{
+ return local64_read(&event->count) + atomic64_read(&event->child_count);
+}
+
+static u64 perf_event_read(struct perf_event *event)
+{
+ /*
+ * If event is enabled and currently active on a CPU, update the
+ * value in the event structure:
+ */
+ if (event->state == PERF_EVENT_STATE_ACTIVE) {
+ smp_call_function_single(event->oncpu,
+ __perf_event_read, event, 1);
+ } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
+ struct perf_event_context *ctx = event->ctx;
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&ctx->lock, flags);
+ /*
+ * may read while context is not active
+ * (e.g., thread is blocked), in that case
+ * we cannot update context time
+ */
+ if (ctx->is_active) {
+ update_context_time(ctx);
+ update_cgrp_time_from_event(event);
+ }
+ update_event_times(event);
+ raw_spin_unlock_irqrestore(&ctx->lock, flags);
+ }
+
+ return perf_event_count(event);
+}
+
+/*
+ * Callchain support
+ */
+
+struct callchain_cpus_entries {
+ struct rcu_head rcu_head;
+ struct perf_callchain_entry *cpu_entries[0];
+};
+
+static DEFINE_PER_CPU(int, callchain_recursion[PERF_NR_CONTEXTS]);
+static atomic_t nr_callchain_events;
+static DEFINE_MUTEX(callchain_mutex);
+struct callchain_cpus_entries *callchain_cpus_entries;
+
+
+__weak void perf_callchain_kernel(struct perf_callchain_entry *entry,
+ struct pt_regs *regs)
+{
+}
+
+__weak void perf_callchain_user(struct perf_callchain_entry *entry,
+ struct pt_regs *regs)
+{
+}
+
+static void release_callchain_buffers_rcu(struct rcu_head *head)
+{
+ struct callchain_cpus_entries *entries;
+ int cpu;
+
+ entries = container_of(head, struct callchain_cpus_entries, rcu_head);
+
+ for_each_possible_cpu(cpu)
+ kfree(entries->cpu_entries[cpu]);
+
+ kfree(entries);
+}
+
+static void release_callchain_buffers(void)
+{
+ struct callchain_cpus_entries *entries;
+
+ entries = callchain_cpus_entries;
+ rcu_assign_pointer(callchain_cpus_entries, NULL);
+ call_rcu(&entries->rcu_head, release_callchain_buffers_rcu);
+}
+
+static int alloc_callchain_buffers(void)
+{
+ int cpu;
+ int size;
+ struct callchain_cpus_entries *entries;
+
+ /*
+ * We can't use the percpu allocation API for data that can be
+ * accessed from NMI. Use a temporary manual per cpu allocation
+ * until that gets sorted out.
+ */
+ size = offsetof(struct callchain_cpus_entries, cpu_entries[nr_cpu_ids]);
+
+ entries = kzalloc(size, GFP_KERNEL);
+ if (!entries)
+ return -ENOMEM;
+
+ size = sizeof(struct perf_callchain_entry) * PERF_NR_CONTEXTS;
+
+ for_each_possible_cpu(cpu) {
+ entries->cpu_entries[cpu] = kmalloc_node(size, GFP_KERNEL,
+ cpu_to_node(cpu));
+ if (!entries->cpu_entries[cpu])
+ goto fail;
+ }
+
+ rcu_assign_pointer(callchain_cpus_entries, entries);
+
+ return 0;
+
+fail:
+ for_each_possible_cpu(cpu)
+ kfree(entries->cpu_entries[cpu]);
+ kfree(entries);
+
+ return -ENOMEM;
+}
+
+static int get_callchain_buffers(void)
+{
+ int err = 0;
+ int count;
+
+ mutex_lock(&callchain_mutex);
+
+ count = atomic_inc_return(&nr_callchain_events);
+ if (WARN_ON_ONCE(count < 1)) {
+ err = -EINVAL;
+ goto exit;
+ }
+
+ if (count > 1) {
+ /* If the allocation failed, give up */
+ if (!callchain_cpus_entries)
+ err = -ENOMEM;
+ goto exit;
+ }
+
+ err = alloc_callchain_buffers();
+ if (err)
+ release_callchain_buffers();
+exit:
+ mutex_unlock(&callchain_mutex);
+
+ return err;
+}
+
+static void put_callchain_buffers(void)
+{
+ if (atomic_dec_and_mutex_lock(&nr_callchain_events, &callchain_mutex)) {
+ release_callchain_buffers();
+ mutex_unlock(&callchain_mutex);
+ }
+}
+
+static int get_recursion_context(int *recursion)
+{
+ int rctx;
+
+ if (in_nmi())
+ rctx = 3;
+ else if (in_irq())
+ rctx = 2;
+ else if (in_softirq())
+ rctx = 1;
+ else
+ rctx = 0;
+
+ if (recursion[rctx])
+ return -1;
+
+ recursion[rctx]++;
+ barrier();
+
+ return rctx;
+}
+
+static inline void put_recursion_context(int *recursion, int rctx)
+{
+ barrier();
+ recursion[rctx]--;
+}
+
+static struct perf_callchain_entry *get_callchain_entry(int *rctx)
+{
+ int cpu;
+ struct callchain_cpus_entries *entries;
+
+ *rctx = get_recursion_context(__get_cpu_var(callchain_recursion));
+ if (*rctx == -1)
+ return NULL;
+
+ entries = rcu_dereference(callchain_cpus_entries);
+ if (!entries)
+ return NULL;
+
+ cpu = smp_processor_id();
+
+ return &entries->cpu_entries[cpu][*rctx];
+}
+
+static void
+put_callchain_entry(int rctx)
+{
+ put_recursion_context(__get_cpu_var(callchain_recursion), rctx);
+}
+
+static struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
+{
+ int rctx;
+ struct perf_callchain_entry *entry;
+
+
+ entry = get_callchain_entry(&rctx);
+ if (rctx == -1)
+ return NULL;
+
+ if (!entry)
+ goto exit_put;
+
+ entry->nr = 0;
+
+ if (!user_mode(regs)) {
+ perf_callchain_store(entry, PERF_CONTEXT_KERNEL);
+ perf_callchain_kernel(entry, regs);
+ if (current->mm)
+ regs = task_pt_regs(current);
+ else
+ regs = NULL;
+ }
+
+ if (regs) {
+ perf_callchain_store(entry, PERF_CONTEXT_USER);
+ perf_callchain_user(entry, regs);
+ }
+
+exit_put:
+ put_callchain_entry(rctx);
+
+ return entry;
+}
+
+/*
+ * Initialize the perf_event context in a task_struct:
+ */
+static void __perf_event_init_context(struct perf_event_context *ctx)
+{
+ raw_spin_lock_init(&ctx->lock);
+ mutex_init(&ctx->mutex);
+ INIT_LIST_HEAD(&ctx->pinned_groups);
+ INIT_LIST_HEAD(&ctx->flexible_groups);
+ INIT_LIST_HEAD(&ctx->event_list);
+ atomic_set(&ctx->refcount, 1);
+}
+
+static struct perf_event_context *
+alloc_perf_context(struct pmu *pmu, struct task_struct *task)
+{
+ struct perf_event_context *ctx;
+
+ ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
+ if (!ctx)
+ return NULL;
+
+ __perf_event_init_context(ctx);
+ if (task) {
+ ctx->task = task;
+ get_task_struct(task);
+ }
+ ctx->pmu = pmu;
+
+ return ctx;
+}
+
+static struct task_struct *
+find_lively_task_by_vpid(pid_t vpid)
+{
+ struct task_struct *task;
+ int err;
+
+ rcu_read_lock();
+ if (!vpid)
+ task = current;
+ else
+ task = find_task_by_vpid(vpid);
+ if (task)
+ get_task_struct(task);
+ rcu_read_unlock();
+
+ if (!task)
+ return ERR_PTR(-ESRCH);
+
+ /* Reuse ptrace permission checks for now. */
+ err = -EACCES;
+ if (!ptrace_may_access(task, PTRACE_MODE_READ))
+ goto errout;
+
+ return task;
+errout:
+ put_task_struct(task);
+ return ERR_PTR(err);
+
+}
+
+/*
+ * Returns a matching context with refcount and pincount.
+ */
+static struct perf_event_context *
+find_get_context(struct pmu *pmu, struct task_struct *task, int cpu)
+{
+ struct perf_event_context *ctx;
+ struct perf_cpu_context *cpuctx;
+ unsigned long flags;
+ int ctxn, err;
+
+ if (!task) {
+ /* Must be root to operate on a CPU event: */
+ if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
+ return ERR_PTR(-EACCES);
+
+ /*
+ * We could be clever and allow to attach a event to an
+ * offline CPU and activate it when the CPU comes up, but
+ * that's for later.
+ */
+ if (!cpu_online(cpu))
+ return ERR_PTR(-ENODEV);
+
+ cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
+ ctx = &cpuctx->ctx;
+ get_ctx(ctx);
+ ++ctx->pin_count;
+
+ return ctx;
+ }
+
+ err = -EINVAL;
+ ctxn = pmu->task_ctx_nr;
+ if (ctxn < 0)
+ goto errout;
+
+retry:
+ ctx = perf_lock_task_context(task, ctxn, &flags);
+ if (ctx) {
+ unclone_ctx(ctx);
+ ++ctx->pin_count;
+ raw_spin_unlock_irqrestore(&ctx->lock, flags);
+ }
+
+ if (!ctx) {
+ ctx = alloc_perf_context(pmu, task);
+ err = -ENOMEM;
+ if (!ctx)
+ goto errout;
+
+ get_ctx(ctx);
+
+ err = 0;
+ mutex_lock(&task->perf_event_mutex);
+ /*
+ * If it has already passed perf_event_exit_task().
+ * we must see PF_EXITING, it takes this mutex too.
+ */
+ if (task->flags & PF_EXITING)
+ err = -ESRCH;
+ else if (task->perf_event_ctxp[ctxn])
+ err = -EAGAIN;
+ else {
+ ++ctx->pin_count;
+ rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
+ }
+ mutex_unlock(&task->perf_event_mutex);
+
+ if (unlikely(err)) {
+ put_task_struct(task);
+ kfree(ctx);
+
+ if (err == -EAGAIN)
+ goto retry;
+ goto errout;
+ }
+ }
+
+ return ctx;
+
+errout:
+ return ERR_PTR(err);
+}
+
+static void perf_event_free_filter(struct perf_event *event);
+
+static void free_event_rcu(struct rcu_head *head)
+{
+ struct perf_event *event;
+
+ event = container_of(head, struct perf_event, rcu_head);
+ if (event->ns)
+ put_pid_ns(event->ns);
+ perf_event_free_filter(event);
+ kfree(event);
+}
+
+static void perf_buffer_put(struct perf_buffer *buffer);
+
+static void free_event(struct perf_event *event)
+{
+ irq_work_sync(&event->pending);
+
+ if (!event->parent) {
+ if (event->attach_state & PERF_ATTACH_TASK)
+ jump_label_dec(&perf_sched_events);
+ if (event->attr.mmap || event->attr.mmap_data)
+ atomic_dec(&nr_mmap_events);
+ if (event->attr.comm)
+ atomic_dec(&nr_comm_events);
+ if (event->attr.task)
+ atomic_dec(&nr_task_events);
+ if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
+ put_callchain_buffers();
+ if (is_cgroup_event(event)) {
+ atomic_dec(&per_cpu(perf_cgroup_events, event->cpu));
+ jump_label_dec(&perf_sched_events);
+ }
+ }
+
+ if (event->buffer) {
+ perf_buffer_put(event->buffer);
+ event->buffer = NULL;
+ }
+
+ if (is_cgroup_event(event))
+ perf_detach_cgroup(event);
+
+ if (event->destroy)
+ event->destroy(event);
+
+ if (event->ctx)
+ put_ctx(event->ctx);
+
+ call_rcu(&event->rcu_head, free_event_rcu);
+}
+
+int perf_event_release_kernel(struct perf_event *event)
+{
+ struct perf_event_context *ctx = event->ctx;
+
+ /*
+ * Remove from the PMU, can't get re-enabled since we got
+ * here because the last ref went.
+ */
+ perf_event_disable(event);
+
+ WARN_ON_ONCE(ctx->parent_ctx);
+ /*
+ * There are two ways this annotation is useful:
+ *
+ * 1) there is a lock recursion from perf_event_exit_task
+ * see the comment there.
+ *
+ * 2) there is a lock-inversion with mmap_sem through
+ * perf_event_read_group(), which takes faults while
+ * holding ctx->mutex, however this is called after
+ * the last filedesc died, so there is no possibility
+ * to trigger the AB-BA case.
+ */
+ mutex_lock_nested(&ctx->mutex, SINGLE_DEPTH_NESTING);
+ raw_spin_lock_irq(&ctx->lock);
+ perf_group_detach(event);
+ list_del_event(event, ctx);
+ raw_spin_unlock_irq(&ctx->lock);
+ mutex_unlock(&ctx->mutex);
+
+ free_event(event);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(perf_event_release_kernel);
+
+/*
+ * Called when the last reference to the file is gone.
+ */
+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);
+}
+
+u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
+{
+ struct perf_event *child;
+ u64 total = 0;
+
+ *enabled = 0;
+ *running = 0;
+
+ mutex_lock(&event->child_mutex);
+ total += perf_event_read(event);
+ *enabled += event->total_time_enabled +
+ atomic64_read(&event->child_total_time_enabled);
+ *running += event->total_time_running +
+ atomic64_read(&event->child_total_time_running);
+
+ list_for_each_entry(child, &event->child_list, child_list) {
+ total += perf_event_read(child);
+ *enabled += child->total_time_enabled;
+ *running += child->total_time_running;
+ }
+ mutex_unlock(&event->child_mutex);
+
+ return total;
+}
+EXPORT_SYMBOL_GPL(perf_event_read_value);
+
+static int perf_event_read_group(struct perf_event *event,
+ u64 read_format, char __user *buf)
+{
+ struct perf_event *leader = event->group_leader, *sub;
+ int n = 0, size = 0, ret = -EFAULT;
+ struct perf_event_context *ctx = leader->ctx;
+ u64 values[5];
+ u64 count, enabled, running;
+
+ mutex_lock(&ctx->mutex);
+ count = perf_event_read_value(leader, &enabled, &running);
+
+ values[n++] = 1 + leader->nr_siblings;
+ if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
+ values[n++] = enabled;
+ if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
+ values[n++] = running;
+ values[n++] = count;
+ if (read_format & PERF_FORMAT_ID)
+ values[n++] = primary_event_id(leader);
+
+ size = n * sizeof(u64);
+
+ if (copy_to_user(buf, values, size))
+ goto unlock;
+
+ ret = size;
+
+ list_for_each_entry(sub, &leader->sibling_list, group_entry) {
+ n = 0;
+
+ values[n++] = perf_event_read_value(sub, &enabled, &running);
+ if (read_format & PERF_FORMAT_ID)
+ values[n++] = primary_event_id(sub);
+
+ size = n * sizeof(u64);
+
+ if (copy_to_user(buf + ret, values, size)) {
+ ret = -EFAULT;
+ goto unlock;
+ }
+
+ ret += size;
+ }
+unlock:
+ mutex_unlock(&ctx->mutex);
+
+ return ret;
+}
+
+static int perf_event_read_one(struct perf_event *event,
+ u64 read_format, char __user *buf)
+{
+ u64 enabled, running;
+ u64 values[4];
+ int n = 0;
+
+ values[n++] = perf_event_read_value(event, &enabled, &running);
+ if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
+ values[n++] = enabled;
+ if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
+ values[n++] = running;
+ if (read_format & PERF_FORMAT_ID)
+ values[n++] = primary_event_id(event);
+
+ if (copy_to_user(buf, values, n * sizeof(u64)))
+ return -EFAULT;
+
+ return n * sizeof(u64);
+}
+
+/*
+ * Read the performance event - simple non blocking version for now
+ */
+static ssize_t
+perf_read_hw(struct perf_event *event, char __user *buf, size_t count)
+{
+ u64 read_format = event->attr.read_format;
+ int ret;
+
+ /*
+ * Return end-of-file for a read on a event that is in
+ * error state (i.e. because it was pinned but it couldn't be
+ * scheduled on to the CPU at some point).
+ */
+ if (event->state == PERF_EVENT_STATE_ERROR)
+ return 0;
+
+ if (count < event->read_size)
+ return -ENOSPC;
+
+ WARN_ON_ONCE(event->ctx->parent_ctx);
+ if (read_format & PERF_FORMAT_GROUP)
+ ret = perf_event_read_group(event, read_format, buf);
+ else
+ ret = perf_event_read_one(event, read_format, buf);
+
+ return ret;
+}
+
+static ssize_t
+perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
+{
+ struct perf_event *event = file->private_data;
+
+ return perf_read_hw(event, buf, count);
+}
+
+static unsigned int perf_poll(struct file *file, poll_table *wait)
+{
+ struct perf_event *event = file->private_data;
+ struct perf_buffer *buffer;
+ unsigned int events = POLL_HUP;
+
+ rcu_read_lock();
+ buffer = rcu_dereference(event->buffer);
+ if (buffer)
+ events = atomic_xchg(&buffer->poll, 0);
+ rcu_read_unlock();
+
+ poll_wait(file, &event->waitq, wait);
+
+ return events;
+}
+
+static void perf_event_reset(struct perf_event *event)
+{
+ (void)perf_event_read(event);
+ local64_set(&event->count, 0);
+ perf_event_update_userpage(event);
+}
+
+/*
+ * Holding the top-level event's child_mutex means that any
+ * descendant process that has inherited this event will block
+ * in sync_child_event if it goes to exit, thus satisfying the
+ * task existence requirements of perf_event_enable/disable.
+ */
+static void perf_event_for_each_child(struct perf_event *event,
+ void (*func)(struct perf_event *))
+{
+ struct perf_event *child;
+
+ WARN_ON_ONCE(event->ctx->parent_ctx);
+ mutex_lock(&event->child_mutex);
+ func(event);
+ list_for_each_entry(child, &event->child_list, child_list)
+ func(child);
+ mutex_unlock(&event->child_mutex);
+}
+
+static void perf_event_for_each(struct perf_event *event,
+ void (*func)(struct perf_event *))
+{
+ struct perf_event_context *ctx = event->ctx;
+ struct perf_event *sibling;
+
+ WARN_ON_ONCE(ctx->parent_ctx);
+ mutex_lock(&ctx->mutex);
+ event = event->group_leader;
+
+ perf_event_for_each_child(event, func);
+ func(event);
+ list_for_each_entry(sibling, &event->sibling_list, group_entry)
+ perf_event_for_each_child(event, func);
+ mutex_unlock(&ctx->mutex);
+}
+
+static int perf_event_period(struct perf_event *event, u64 __user *arg)
+{
+ struct perf_event_context *ctx = event->ctx;
+ int ret = 0;
+ u64 value;
+
+ if (!is_sampling_event(event))
+ return -EINVAL;
+
+ if (copy_from_user(&value, arg, sizeof(value)))
+ return -EFAULT;
+
+ if (!value)
+ return -EINVAL;
+
+ raw_spin_lock_irq(&ctx->lock);
+ if (event->attr.freq) {
+ if (value > sysctl_perf_event_sample_rate) {
+ ret = -EINVAL;
+ goto unlock;
+ }
+
+ event->attr.sample_freq = value;
+ } else {
+ event->attr.sample_period = value;
+ event->hw.sample_period = value;
+ }
+unlock:
+ raw_spin_unlock_irq(&ctx->lock);
+
+ return ret;
+}
+
+static const struct file_operations perf_fops;
+
+static struct perf_event *perf_fget_light(int fd, int *fput_needed)
+{
+ struct file *file;
+
+ file = fget_light(fd, fput_needed);
+ if (!file)
+ return ERR_PTR(-EBADF);
+
+ if (file->f_op != &perf_fops) {
+ fput_light(file, *fput_needed);
+ *fput_needed = 0;
+ return ERR_PTR(-EBADF);
+ }
+
+ return file->private_data;
+}
+
+static int perf_event_set_output(struct perf_event *event,
+ struct perf_event *output_event);
+static int perf_event_set_filter(struct perf_event *event, void __user *arg);
+
+static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+ struct perf_event *event = file->private_data;
+ void (*func)(struct perf_event *);
+ u32 flags = arg;
+
+ switch (cmd) {
+ case PERF_EVENT_IOC_ENABLE:
+ func = perf_event_enable;
+ break;
+ case PERF_EVENT_IOC_DISABLE:
+ func = perf_event_disable;
+ break;
+ case PERF_EVENT_IOC_RESET:
+ func = perf_event_reset;
+ break;
+
+ case PERF_EVENT_IOC_REFRESH:
+ return perf_event_refresh(event, arg);
+
+ case PERF_EVENT_IOC_PERIOD:
+ return perf_event_period(event, (u64 __user *)arg);
+
+ case PERF_EVENT_IOC_SET_OUTPUT:
+ {
+ struct perf_event *output_event = NULL;
+ int fput_needed = 0;
+ int ret;
+
+ if (arg != -1) {
+ output_event = perf_fget_light(arg, &fput_needed);
+ if (IS_ERR(output_event))
+ return PTR_ERR(output_event);
+ }
+
+ ret = perf_event_set_output(event, output_event);
+ if (output_event)
+ fput_light(output_event->filp, fput_needed);
+
+ return ret;
+ }
+
+ case PERF_EVENT_IOC_SET_FILTER:
+ return perf_event_set_filter(event, (void __user *)arg);
+
+ default:
+ return -ENOTTY;
+ }
+
+ if (flags & PERF_IOC_FLAG_GROUP)
+ perf_event_for_each(event, func);
+ else
+ perf_event_for_each_child(event, func);
+
+ return 0;
+}
+
+int perf_event_task_enable(void)
+{
+ struct perf_event *event;
+
+ mutex_lock(¤t->perf_event_mutex);
+ list_for_each_entry(event, ¤t->perf_event_list, owner_entry)
+ perf_event_for_each_child(event, perf_event_enable);
+ mutex_unlock(¤t->perf_event_mutex);
+
+ return 0;
+}
+
+int perf_event_task_disable(void)
+{
+ struct perf_event *event;
+
+ mutex_lock(¤t->perf_event_mutex);
+ list_for_each_entry(event, ¤t->perf_event_list, owner_entry)
+ perf_event_for_each_child(event, perf_event_disable);
+ mutex_unlock(¤t->perf_event_mutex);
+
+ return 0;
+}
+
+#ifndef PERF_EVENT_INDEX_OFFSET
+# define PERF_EVENT_INDEX_OFFSET 0
+#endif
+
+static int perf_event_index(struct perf_event *event)
+{
+ if (event->hw.state & PERF_HES_STOPPED)
+ return 0;
+
+ if (event->state != PERF_EVENT_STATE_ACTIVE)
+ return 0;
+
+ return event->hw.idx + 1 - PERF_EVENT_INDEX_OFFSET;
+}
+
+/*
+ * Callers need to ensure there can be no nesting of this function, otherwise
+ * the seqlock logic goes bad. We can not serialize this because the arch
+ * code calls this from NMI context.
+ */
+void perf_event_update_userpage(struct perf_event *event)
+{
+ struct perf_event_mmap_page *userpg;
+ struct perf_buffer *buffer;
+
+ rcu_read_lock();
+ buffer = rcu_dereference(event->buffer);
+ if (!buffer)
+ goto unlock;
+
+ userpg = buffer->user_page;
+
+ /*
+ * Disable preemption so as to not let the corresponding user-space
+ * spin too long if we get preempted.
+ */
+ preempt_disable();
+ ++userpg->lock;
+ barrier();
+ userpg->index = perf_event_index(event);
+ userpg->offset = perf_event_count(event);
+ if (event->state == PERF_EVENT_STATE_ACTIVE)
+ userpg->offset -= local64_read(&event->hw.prev_count);
+
+ userpg->time_enabled = event->total_time_enabled +
+ atomic64_read(&event->child_total_time_enabled);
+
+ userpg->time_running = event->total_time_running +
+ atomic64_read(&event->child_total_time_running);
+
+ barrier();
+ ++userpg->lock;
+ preempt_enable();
+unlock:
+ rcu_read_unlock();
+}
+
+static unsigned long perf_data_size(struct perf_buffer *buffer);
+
+static void
+perf_buffer_init(struct perf_buffer *buffer, long watermark, int flags)
+{
+ long max_size = perf_data_size(buffer);
+
+ if (watermark)
+ buffer->watermark = min(max_size, watermark);
+
+ if (!buffer->watermark)
+ buffer->watermark = max_size / 2;
+
+ if (flags & PERF_BUFFER_WRITABLE)
+ buffer->writable = 1;
+
+ atomic_set(&buffer->refcount, 1);
+}
+
+#ifndef CONFIG_PERF_USE_VMALLOC
+
+/*
+ * Back perf_mmap() with regular GFP_KERNEL-0 pages.
+ */
+
+static struct page *
+perf_mmap_to_page(struct perf_buffer *buffer, unsigned long pgoff)
+{
+ if (pgoff > buffer->nr_pages)
+ return NULL;
+
+ if (pgoff == 0)
+ return virt_to_page(buffer->user_page);
+
+ return virt_to_page(buffer->data_pages[pgoff - 1]);
+}
+
+static void *perf_mmap_alloc_page(int cpu)
+{
+ struct page *page;
+ int node;
+
+ node = (cpu == -1) ? cpu : cpu_to_node(cpu);
+ page = alloc_pages_node(node, GFP_KERNEL | __GFP_ZERO, 0);
+ if (!page)
+ return NULL;
+
+ return page_address(page);
+}
+
+static struct perf_buffer *
+perf_buffer_alloc(int nr_pages, long watermark, int cpu, int flags)
+{
+ struct perf_buffer *buffer;
+ unsigned long size;
+ int i;
+
+ size = sizeof(struct perf_buffer);
+ size += nr_pages * sizeof(void *);
+
+ buffer = kzalloc(size, GFP_KERNEL);
+ if (!buffer)
+ goto fail;
+
+ buffer->user_page = perf_mmap_alloc_page(cpu);
+ if (!buffer->user_page)
+ goto fail_user_page;
+
+ for (i = 0; i < nr_pages; i++) {
+ buffer->data_pages[i] = perf_mmap_alloc_page(cpu);
+ if (!buffer->data_pages[i])
+ goto fail_data_pages;
+ }
+
+ buffer->nr_pages = nr_pages;
+
+ perf_buffer_init(buffer, watermark, flags);
+
+ return buffer;
+
+fail_data_pages:
+ for (i--; i >= 0; i--)
+ free_page((unsigned long)buffer->data_pages[i]);
+
+ free_page((unsigned long)buffer->user_page);
+
+fail_user_page:
+ kfree(buffer);
+
+fail:
+ return NULL;
+}
+
+static void perf_mmap_free_page(unsigned long addr)
+{
+ struct page *page = virt_to_page((void *)addr);
+
+ page->mapping = NULL;
+ __free_page(page);
+}
+
+static void perf_buffer_free(struct perf_buffer *buffer)
+{
+ int i;
+
+ perf_mmap_free_page((unsigned long)buffer->user_page);
+ for (i = 0; i < buffer->nr_pages; i++)
+ perf_mmap_free_page((unsigned long)buffer->data_pages[i]);
+ kfree(buffer);
+}
+
+static inline int page_order(struct perf_buffer *buffer)
+{
+ return 0;
+}
+
+#else
+
+/*
+ * Back perf_mmap() with vmalloc memory.
+ *
+ * Required for architectures that have d-cache aliasing issues.
+ */
+
+static inline int page_order(struct perf_buffer *buffer)
+{
+ return buffer->page_order;
+}
+
+static struct page *
+perf_mmap_to_page(struct perf_buffer *buffer, unsigned long pgoff)
+{
+ if (pgoff > (1UL << page_order(buffer)))
+ return NULL;
+
+ return vmalloc_to_page((void *)buffer->user_page + pgoff * PAGE_SIZE);
+}
+
+static void perf_mmap_unmark_page(void *addr)
+{
+ struct page *page = vmalloc_to_page(addr);
+
+ page->mapping = NULL;
+}
+
+static void perf_buffer_free_work(struct work_struct *work)
+{
+ struct perf_buffer *buffer;
+ void *base;
+ int i, nr;
+
+ buffer = container_of(work, struct perf_buffer, work);
+ nr = 1 << page_order(buffer);
+
+ base = buffer->user_page;
+ for (i = 0; i < nr + 1; i++)
+ perf_mmap_unmark_page(base + (i * PAGE_SIZE));
+
+ vfree(base);
+ kfree(buffer);
+}
+
+static void perf_buffer_free(struct perf_buffer *buffer)
+{
+ schedule_work(&buffer->work);
+}
+
+static struct perf_buffer *
+perf_buffer_alloc(int nr_pages, long watermark, int cpu, int flags)
+{
+ struct perf_buffer *buffer;
+ unsigned long size;
+ void *all_buf;
+
+ size = sizeof(struct perf_buffer);
+ size += sizeof(void *);
+
+ buffer = kzalloc(size, GFP_KERNEL);
+ if (!buffer)
+ goto fail;
+
+ INIT_WORK(&buffer->work, perf_buffer_free_work);
+
+ all_buf = vmalloc_user((nr_pages + 1) * PAGE_SIZE);
+ if (!all_buf)
+ goto fail_all_buf;
+
+ buffer->user_page = all_buf;
+ buffer->data_pages[0] = all_buf + PAGE_SIZE;
+ buffer->page_order = ilog2(nr_pages);
+ buffer->nr_pages = 1;
+
+ perf_buffer_init(buffer, watermark, flags);
+
+ return buffer;
+
+fail_all_buf:
+ kfree(buffer);
+
+fail:
+ return NULL;
+}
+
+#endif
+
+static unsigned long perf_data_size(struct perf_buffer *buffer)
+{
+ return buffer->nr_pages << (PAGE_SHIFT + page_order(buffer));
+}
+
+static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+ struct perf_event *event = vma->vm_file->private_data;
+ struct perf_buffer *buffer;
+ int ret = VM_FAULT_SIGBUS;
+
+ if (vmf->flags & FAULT_FLAG_MKWRITE) {
+ if (vmf->pgoff == 0)
+ ret = 0;
+ return ret;
+ }
+
+ rcu_read_lock();
+ buffer = rcu_dereference(event->buffer);
+ if (!buffer)
+ goto unlock;
+
+ if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
+ goto unlock;
+
+ vmf->page = perf_mmap_to_page(buffer, vmf->pgoff);
+ if (!vmf->page)
+ goto unlock;
+
+ get_page(vmf->page);
+ vmf->page->mapping = vma->vm_file->f_mapping;
+ vmf->page->index = vmf->pgoff;
+
+ ret = 0;
+unlock:
+ rcu_read_unlock();
+
+ return ret;
+}
+
+static void perf_buffer_free_rcu(struct rcu_head *rcu_head)
+{
+ struct perf_buffer *buffer;
+
+ buffer = container_of(rcu_head, struct perf_buffer, rcu_head);
+ perf_buffer_free(buffer);
+}
+
+static struct perf_buffer *perf_buffer_get(struct perf_event *event)
+{
+ struct perf_buffer *buffer;
+
+ rcu_read_lock();
+ buffer = rcu_dereference(event->buffer);
+ if (buffer) {
+ if (!atomic_inc_not_zero(&buffer->refcount))
+ buffer = NULL;
+ }
+ rcu_read_unlock();
+
+ return buffer;
+}
+
+static void perf_buffer_put(struct perf_buffer *buffer)
+{
+ if (!atomic_dec_and_test(&buffer->refcount))
+ return;
+
+ call_rcu(&buffer->rcu_head, perf_buffer_free_rcu);
+}
+
+static void perf_mmap_open(struct vm_area_struct *vma)
+{
+ struct perf_event *event = vma->vm_file->private_data;
+
+ atomic_inc(&event->mmap_count);
+}
+
+static void perf_mmap_close(struct vm_area_struct *vma)
+{
+ struct perf_event *event = vma->vm_file->private_data;
+
+ if (atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) {
+ unsigned long size = perf_data_size(event->buffer);
+ struct user_struct *user = event->mmap_user;
+ struct perf_buffer *buffer = event->buffer;
+
+ atomic_long_sub((size >> PAGE_SHIFT) + 1, &user->locked_vm);
+ vma->vm_mm->locked_vm -= event->mmap_locked;
+ rcu_assign_pointer(event->buffer, NULL);
+ mutex_unlock(&event->mmap_mutex);
+
+ perf_buffer_put(buffer);
+ free_uid(user);
+ }
+}
+
+static const struct vm_operations_struct perf_mmap_vmops = {
+ .open = perf_mmap_open,
+ .close = perf_mmap_close,
+ .fault = perf_mmap_fault,
+ .page_mkwrite = perf_mmap_fault,
+};
+
+static int perf_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ struct perf_event *event = file->private_data;
+ unsigned long user_locked, user_lock_limit;
+ struct user_struct *user = current_user();
+ unsigned long locked, lock_limit;
+ struct perf_buffer *buffer;
+ unsigned long vma_size;
+ unsigned long nr_pages;
+ long user_extra, extra;
+ int ret = 0, flags = 0;
+
+ /*
+ * Don't allow mmap() of inherited per-task counters. This would
+ * create a performance issue due to all children writing to the
+ * same buffer.
+ */
+ if (event->cpu == -1 && event->attr.inherit)
+ return -EINVAL;
+
+ if (!(vma->vm_flags & VM_SHARED))
+ return -EINVAL;
+
+ vma_size = vma->vm_end - vma->vm_start;
+ nr_pages = (vma_size / PAGE_SIZE) - 1;
+
+ /*
+ * If we have buffer pages ensure they're a power-of-two number, so we
+ * can do bitmasks instead of modulo.
+ */
+ if (nr_pages != 0 && !is_power_of_2(nr_pages))
+ return -EINVAL;
+
+ if (vma_size != PAGE_SIZE * (1 + nr_pages))
+ return -EINVAL;
+
+ if (vma->vm_pgoff != 0)
+ return -EINVAL;
+
+ WARN_ON_ONCE(event->ctx->parent_ctx);
+ mutex_lock(&event->mmap_mutex);
+ if (event->buffer) {
+ if (event->buffer->nr_pages == nr_pages)
+ atomic_inc(&event->buffer->refcount);
+ else
+ ret = -EINVAL;
+ goto unlock;
+ }
+
+ user_extra = nr_pages + 1;
+ user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
+
+ /*
+ * Increase the limit linearly with more CPUs:
+ */
+ user_lock_limit *= num_online_cpus();
+
+ user_locked = atomic_long_read(&user->locked_vm) + user_extra;
+
+ extra = 0;
+ if (user_locked > user_lock_limit)
+ extra = user_locked - user_lock_limit;
+
+ lock_limit = rlimit(RLIMIT_MEMLOCK);
+ lock_limit >>= PAGE_SHIFT;
+ locked = vma->vm_mm->locked_vm + extra;
+
+ if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
+ !capable(CAP_IPC_LOCK)) {
+ ret = -EPERM;
+ goto unlock;
+ }
+
+ WARN_ON(event->buffer);
+
+ if (vma->vm_flags & VM_WRITE)
+ flags |= PERF_BUFFER_WRITABLE;
+
+ buffer = perf_buffer_alloc(nr_pages, event->attr.wakeup_watermark,
+ event->cpu, flags);
+ if (!buffer) {
+ ret = -ENOMEM;
+ goto unlock;
+ }
+ rcu_assign_pointer(event->buffer, buffer);
+
+ atomic_long_add(user_extra, &user->locked_vm);
+ event->mmap_locked = extra;
+ event->mmap_user = get_current_user();
+ vma->vm_mm->locked_vm += event->mmap_locked;
+
+unlock:
+ if (!ret)
+ atomic_inc(&event->mmap_count);
+ mutex_unlock(&event->mmap_mutex);
+
+ vma->vm_flags |= VM_RESERVED;
+ vma->vm_ops = &perf_mmap_vmops;
+
+ return ret;
+}
+
+static int perf_fasync(int fd, struct file *filp, int on)
+{
+ struct inode *inode = filp->f_path.dentry->d_inode;
+ struct perf_event *event = filp->private_data;
+ int retval;
+
+ mutex_lock(&inode->i_mutex);
+ retval = fasync_helper(fd, filp, on, &event->fasync);
+ mutex_unlock(&inode->i_mutex);
+
+ if (retval < 0)
+ return retval;
+
+ return 0;
+}
+
+static const struct file_operations perf_fops = {
+ .llseek = no_llseek,
+ .release = perf_release,
+ .read = perf_read,
+ .poll = perf_poll,
+ .unlocked_ioctl = perf_ioctl,
+ .compat_ioctl = perf_ioctl,
+ .mmap = perf_mmap,
+ .fasync = perf_fasync,
+};
+
+/*
+ * Perf event wakeup
+ *
+ * If there's data, ensure we set the poll() state and publish everything
+ * to user-space before waking everybody up.
+ */
+
+void perf_event_wakeup(struct perf_event *event)
+{
+ wake_up_all(&event->waitq);
+
+ if (event->pending_kill) {
+ kill_fasync(&event->fasync, SIGIO, event->pending_kill);
+ event->pending_kill = 0;
+ }
+}
+
+static void perf_pending_event(struct irq_work *entry)
+{
+ struct perf_event *event = container_of(entry,
+ struct perf_event, pending);
+
+ if (event->pending_disable) {
+ event->pending_disable = 0;
+ __perf_event_disable(event);
+ }
+
+ if (event->pending_wakeup) {
+ event->pending_wakeup = 0;
+ perf_event_wakeup(event);
+ }
+}
+
+/*
+ * We assume there is only KVM supporting the callbacks.
+ * Later on, we might change it to a list if there is
+ * another virtualization implementation supporting the callbacks.
+ */
+struct perf_guest_info_callbacks *perf_guest_cbs;
+
+int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
+{
+ perf_guest_cbs = cbs;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
+
+int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
+{
+ perf_guest_cbs = NULL;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
+
+/*
+ * Output
+ */
+static bool perf_output_space(struct perf_buffer *buffer, unsigned long tail,
+ unsigned long offset, unsigned long head)
+{
+ unsigned long mask;
+
+ if (!buffer->writable)
+ return true;
+
+ mask = perf_data_size(buffer) - 1;
+
+ offset = (offset - tail) & mask;
+ head = (head - tail) & mask;
+
+ if ((int)(head - offset) < 0)
+ return false;
+
+ return true;
+}
+
+static void perf_output_wakeup(struct perf_output_handle *handle)
+{
+ atomic_set(&handle->buffer->poll, POLL_IN);
+
+ if (handle->nmi) {
+ handle->event->pending_wakeup = 1;
+ irq_work_queue(&handle->event->pending);
+ } else
+ perf_event_wakeup(handle->event);
+}
+
+/*
+ * We need to ensure a later event_id doesn't publish a head when a former
+ * event isn't done writing. However since we need to deal with NMIs we
+ * cannot fully serialize things.
+ *
+ * We only publish the head (and generate a wakeup) when the outer-most
+ * event completes.
+ */
+static void perf_output_get_handle(struct perf_output_handle *handle)
+{
+ struct perf_buffer *buffer = handle->buffer;
+
+ preempt_disable();
+ local_inc(&buffer->nest);
+ handle->wakeup = local_read(&buffer->wakeup);
+}
+
+static void perf_output_put_handle(struct perf_output_handle *handle)
+{
+ struct perf_buffer *buffer = handle->buffer;
+ unsigned long head;
+
+again:
+ head = local_read(&buffer->head);
+
+ /*
+ * IRQ/NMI can happen here, which means we can miss a head update.
+ */
+
+ if (!local_dec_and_test(&buffer->nest))
+ goto out;
+
+ /*
+ * Publish the known good head. Rely on the full barrier implied
+ * by atomic_dec_and_test() order the buffer->head read and this
+ * write.
+ */
+ buffer->user_page->data_head = head;
+
+ /*
+ * Now check if we missed an update, rely on the (compiler)
+ * barrier in atomic_dec_and_test() to re-read buffer->head.
+ */
+ if (unlikely(head != local_read(&buffer->head))) {
+ local_inc(&buffer->nest);
+ goto again;
+ }
+
+ if (handle->wakeup != local_read(&buffer->wakeup))
+ perf_output_wakeup(handle);
+
+out:
+ preempt_enable();
+}
+
+__always_inline void perf_output_copy(struct perf_output_handle *handle,
+ const void *buf, unsigned int len)
+{
+ do {
+ unsigned long size = min_t(unsigned long, handle->size, len);
+
+ memcpy(handle->addr, buf, size);
+
+ len -= size;
+ handle->addr += size;
+ buf += size;
+ handle->size -= size;
+ if (!handle->size) {
+ struct perf_buffer *buffer = handle->buffer;
+
+ handle->page++;
+ handle->page &= buffer->nr_pages - 1;
+ handle->addr = buffer->data_pages[handle->page];
+ handle->size = PAGE_SIZE << page_order(buffer);
+ }
+ } while (len);
+}
+
+static void __perf_event_header__init_id(struct perf_event_header *header,
+ struct perf_sample_data *data,
+ struct perf_event *event)
+{
+ u64 sample_type = event->attr.sample_type;
+
+ data->type = sample_type;
+ header->size += event->id_header_size;
+
+ if (sample_type & PERF_SAMPLE_TID) {
+ /* namespace issues */
+ data->tid_entry.pid = perf_event_pid(event, current);
+ data->tid_entry.tid = perf_event_tid(event, current);
+ }
+
+ if (sample_type & PERF_SAMPLE_TIME)
+ data->time = perf_clock();
+
+ if (sample_type & PERF_SAMPLE_ID)
+ data->id = primary_event_id(event);
+
+ if (sample_type & PERF_SAMPLE_STREAM_ID)
+ data->stream_id = event->id;
+
+ if (sample_type & PERF_SAMPLE_CPU) {
+ data->cpu_entry.cpu = raw_smp_processor_id();
+ data->cpu_entry.reserved = 0;
+ }
+}
+
+static void perf_event_header__init_id(struct perf_event_header *header,
+ struct perf_sample_data *data,
+ struct perf_event *event)
+{
+ if (event->attr.sample_id_all)
+ __perf_event_header__init_id(header, data, event);
+}
+
+static void __perf_event__output_id_sample(struct perf_output_handle *handle,
+ struct perf_sample_data *data)
+{
+ u64 sample_type = data->type;
+
+ if (sample_type & PERF_SAMPLE_TID)
+ perf_output_put(handle, data->tid_entry);
+
+ if (sample_type & PERF_SAMPLE_TIME)
+ perf_output_put(handle, data->time);
+
+ if (sample_type & PERF_SAMPLE_ID)
+ perf_output_put(handle, data->id);
+
+ if (sample_type & PERF_SAMPLE_STREAM_ID)
+ perf_output_put(handle, data->stream_id);
+
+ if (sample_type & PERF_SAMPLE_CPU)
+ perf_output_put(handle, data->cpu_entry);
+}
+
+static void perf_event__output_id_sample(struct perf_event *event,
+ struct perf_output_handle *handle,
+ struct perf_sample_data *sample)
+{
+ if (event->attr.sample_id_all)
+ __perf_event__output_id_sample(handle, sample);
+}
+
+int perf_output_begin(struct perf_output_handle *handle,
+ struct perf_event *event, unsigned int size,
+ int nmi, int sample)
+{
+ struct perf_buffer *buffer;
+ unsigned long tail, offset, head;
+ int have_lost;
+ struct perf_sample_data sample_data;
+ struct {
+ struct perf_event_header header;
+ u64 id;
+ u64 lost;
+ } lost_event;
+
+ rcu_read_lock();
+ /*
+ * For inherited events we send all the output towards the parent.
+ */
+ if (event->parent)
+ event = event->parent;
+
+ buffer = rcu_dereference(event->buffer);
+ if (!buffer)
+ goto out;
+
+ handle->buffer = buffer;
+ handle->event = event;
+ handle->nmi = nmi;
+ handle->sample = sample;
+
+ if (!buffer->nr_pages)
+ goto out;
+
+ have_lost = local_read(&buffer->lost);
+ if (have_lost) {
+ lost_event.header.size = sizeof(lost_event);
+ perf_event_header__init_id(&lost_event.header, &sample_data,
+ event);
+ size += lost_event.header.size;
+ }
+
+ perf_output_get_handle(handle);
+
+ do {
+ /*
+ * Userspace could choose to issue a mb() before updating the
+ * tail pointer. So that all reads will be completed before the
+ * write is issued.
+ */
+ tail = ACCESS_ONCE(buffer->user_page->data_tail);
+ smp_rmb();
+ offset = head = local_read(&buffer->head);
+ head += size;
+ if (unlikely(!perf_output_space(buffer, tail, offset, head)))
+ goto fail;
+ } while (local_cmpxchg(&buffer->head, offset, head) != offset);
+
+ if (head - local_read(&buffer->wakeup) > buffer->watermark)
+ local_add(buffer->watermark, &buffer->wakeup);
+
+ handle->page = offset >> (PAGE_SHIFT + page_order(buffer));
+ handle->page &= buffer->nr_pages - 1;
+ handle->size = offset & ((PAGE_SIZE << page_order(buffer)) - 1);
+ handle->addr = buffer->data_pages[handle->page];
+ handle->addr += handle->size;
+ handle->size = (PAGE_SIZE << page_order(buffer)) - handle->size;
+
+ if (have_lost) {
+ lost_event.header.type = PERF_RECORD_LOST;
+ lost_event.header.misc = 0;
+ lost_event.id = event->id;
+ lost_event.lost = local_xchg(&buffer->lost, 0);
+
+ perf_output_put(handle, lost_event);
+ perf_event__output_id_sample(event, handle, &sample_data);
+ }
+
+ return 0;
+
+fail:
+ local_inc(&buffer->lost);
+ perf_output_put_handle(handle);
+out:
+ rcu_read_unlock();
+
+ return -ENOSPC;
+}
+
+void perf_output_end(struct perf_output_handle *handle)
+{
+ struct perf_event *event = handle->event;
+ struct perf_buffer *buffer = handle->buffer;
+
+ int wakeup_events = event->attr.wakeup_events;
+
+ if (handle->sample && wakeup_events) {
+ int events = local_inc_return(&buffer->events);
+ if (events >= wakeup_events) {
+ local_sub(wakeup_events, &buffer->events);
+ local_inc(&buffer->wakeup);
+ }
+ }
+
+ perf_output_put_handle(handle);
+ rcu_read_unlock();
+}
+
+static void perf_output_read_one(struct perf_output_handle *handle,
+ struct perf_event *event,
+ u64 enabled, u64 running)
+{
+ u64 read_format = event->attr.read_format;
+ u64 values[4];
+ int n = 0;
+
+ values[n++] = perf_event_count(event);
+ if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
+ values[n++] = enabled +
+ atomic64_read(&event->child_total_time_enabled);
+ }
+ if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
+ values[n++] = running +
+ atomic64_read(&event->child_total_time_running);
+ }
+ if (read_format & PERF_FORMAT_ID)
+ values[n++] = primary_event_id(event);
+
+ perf_output_copy(handle, values, n * sizeof(u64));
+}
+
+/*
+ * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
+ */
+static void perf_output_read_group(struct perf_output_handle *handle,
+ struct perf_event *event,
+ u64 enabled, u64 running)
+{
+ struct perf_event *leader = event->group_leader, *sub;
+ u64 read_format = event->attr.read_format;
+ u64 values[5];
+ int n = 0;
+
+ values[n++] = 1 + leader->nr_siblings;
+
+ if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
+ values[n++] = enabled;
+
+ if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
+ values[n++] = running;
+
+ if (leader != event)
+ leader->pmu->read(leader);
+
+ values[n++] = perf_event_count(leader);
+ if (read_format & PERF_FORMAT_ID)
+ values[n++] = primary_event_id(leader);
+
+ perf_output_copy(handle, values, n * sizeof(u64));
+
+ list_for_each_entry(sub, &leader->sibling_list, group_entry) {
+ n = 0;
+
+ if (sub != event)
+ sub->pmu->read(sub);
+
+ values[n++] = perf_event_count(sub);
+ if (read_format & PERF_FORMAT_ID)
+ values[n++] = primary_event_id(sub);
+
+ perf_output_copy(handle, values, n * sizeof(u64));
+ }
+}
+
+#define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
+ PERF_FORMAT_TOTAL_TIME_RUNNING)
+
+static void perf_output_read(struct perf_output_handle *handle,
+ struct perf_event *event)
+{
+ u64 enabled = 0, running = 0, now, ctx_time;
+ u64 read_format = event->attr.read_format;
+
+ /*
+ * compute total_time_enabled, total_time_running
+ * based on snapshot values taken when the event
+ * was last scheduled in.
+ *
+ * we cannot simply called update_context_time()
+ * because of locking issue as we are called in
+ * NMI context
+ */
+ if (read_format & PERF_FORMAT_TOTAL_TIMES) {
+ now = perf_clock();
+ ctx_time = event->shadow_ctx_time + now;
+ enabled = ctx_time - event->tstamp_enabled;
+ running = ctx_time - event->tstamp_running;
+ }
+
+ if (event->attr.read_format & PERF_FORMAT_GROUP)
+ perf_output_read_group(handle, event, enabled, running);
+ else
+ perf_output_read_one(handle, event, enabled, running);
+}
+
+void perf_output_sample(struct perf_output_handle *handle,
+ struct perf_event_header *header,
+ struct perf_sample_data *data,
+ struct perf_event *event)
+{
+ u64 sample_type = data->type;
+
+ perf_output_put(handle, *header);
+
+ if (sample_type & PERF_SAMPLE_IP)
+ perf_output_put(handle, data->ip);
+
+ if (sample_type & PERF_SAMPLE_TID)
+ perf_output_put(handle, data->tid_entry);
+
+ if (sample_type & PERF_SAMPLE_TIME)
+ perf_output_put(handle, data->time);
+
+ if (sample_type & PERF_SAMPLE_ADDR)
+ perf_output_put(handle, data->addr);
+
+ if (sample_type & PERF_SAMPLE_ID)
+ perf_output_put(handle, data->id);
+
+ if (sample_type & PERF_SAMPLE_STREAM_ID)
+ perf_output_put(handle, data->stream_id);
+
+ if (sample_type & PERF_SAMPLE_CPU)
+ perf_output_put(handle, data->cpu_entry);
+
+ if (sample_type & PERF_SAMPLE_PERIOD)
+ perf_output_put(handle, data->period);
+
+ if (sample_type & PERF_SAMPLE_READ)
+ perf_output_read(handle, event);
+
+ if (sample_type & PERF_SAMPLE_CALLCHAIN) {
+ if (data->callchain) {
+ int size = 1;
+
+ if (data->callchain)
+ size += data->callchain->nr;
+
+ size *= sizeof(u64);
+
+ perf_output_copy(handle, data->callchain, size);
+ } else {
+ u64 nr = 0;
+ perf_output_put(handle, nr);
+ }
+ }
+
+ if (sample_type & PERF_SAMPLE_RAW) {
+ if (data->raw) {
+ perf_output_put(handle, data->raw->size);
+ perf_output_copy(handle, data->raw->data,
+ data->raw->size);
+ } else {
+ struct {
+ u32 size;
+ u32 data;
+ } raw = {
+ .size = sizeof(u32),
+ .data = 0,
+ };
+ perf_output_put(handle, raw);
+ }
+ }
+}
+
+void perf_prepare_sample(struct perf_event_header *header,
+ struct perf_sample_data *data,
+ struct perf_event *event,
+ struct pt_regs *regs)
+{
+ u64 sample_type = event->attr.sample_type;
+
+ header->type = PERF_RECORD_SAMPLE;
+ header->size = sizeof(*header) + event->header_size;
+
+ header->misc = 0;
+ header->misc |= perf_misc_flags(regs);
+
+ __perf_event_header__init_id(header, data, event);
+
+ if (sample_type & PERF_SAMPLE_IP)
+ data->ip = perf_instruction_pointer(regs);
+
+ if (sample_type & PERF_SAMPLE_CALLCHAIN) {
+ int size = 1;
+
+ data->callchain = perf_callchain(regs);
+
+ if (data->callchain)
+ size += data->callchain->nr;
+
+ header->size += size * sizeof(u64);
+ }
+
+ if (sample_type & PERF_SAMPLE_RAW) {
+ int size = sizeof(u32);
+
+ if (data->raw)
+ size += data->raw->size;
+ else
+ size += sizeof(u32);
+
+ WARN_ON_ONCE(size & (sizeof(u64)-1));
+ header->size += size;
+ }
+}
+
+static void perf_event_output(struct perf_event *event, int nmi,
+ struct perf_sample_data *data,
+ struct pt_regs *regs)
+{
+ struct perf_output_handle handle;
+ struct perf_event_header header;
+
+ /* protect the callchain buffers */
+ rcu_read_lock();
+
+ perf_prepare_sample(&header, data, event, regs);
+
+ if (perf_output_begin(&handle, event, header.size, nmi, 1))
+ goto exit;
+
+ perf_output_sample(&handle, &header, data, event);
+
+ perf_output_end(&handle);
+
+exit:
+ rcu_read_unlock();
+}
+
+/*
+ * read event_id
+ */
+
+struct perf_read_event {
+ struct perf_event_header header;
+
+ u32 pid;
+ u32 tid;
+};
+
+static void
+perf_event_read_event(struct perf_event *event,
+ struct task_struct *task)
+{
+ struct perf_output_handle handle;
+ struct perf_sample_data sample;
+ struct perf_read_event read_event = {
+ .header = {
+ .type = PERF_RECORD_READ,
+ .misc = 0,
+ .size = sizeof(read_event) + event->read_size,
+ },
+ .pid = perf_event_pid(event, task),
+ .tid = perf_event_tid(event, task),
+ };
+ int ret;
+
+ perf_event_header__init_id(&read_event.header, &sample, event);
+ ret = perf_output_begin(&handle, event, read_event.header.size, 0, 0);
+ if (ret)
+ return;
+
+ perf_output_put(&handle, read_event);
+ perf_output_read(&handle, event);
+ perf_event__output_id_sample(event, &handle, &sample);
+
+ perf_output_end(&handle);
+}
+
+/*
+ * task tracking -- fork/exit
+ *
+ * enabled by: attr.comm | attr.mmap | attr.mmap_data | attr.task
+ */
+
+struct perf_task_event {
+ struct task_struct *task;
+ struct perf_event_context *task_ctx;
+
+ struct {
+ struct perf_event_header header;
+
+ u32 pid;
+ u32 ppid;
+ u32 tid;
+ u32 ptid;
+ u64 time;
+ } event_id;
+};
+
+static void perf_event_task_output(struct perf_event *event,
+ struct perf_task_event *task_event)
+{
+ struct perf_output_handle handle;
+ struct perf_sample_data sample;
+ struct task_struct *task = task_event->task;
+ int ret, size = task_event->event_id.header.size;
+
+ perf_event_header__init_id(&task_event->event_id.header, &sample, event);
+
+ ret = perf_output_begin(&handle, event,
+ task_event->event_id.header.size, 0, 0);
+ if (ret)
+ goto out;
+
+ task_event->event_id.pid = perf_event_pid(event, task);
+ task_event->event_id.ppid = perf_event_pid(event, current);
+
+ task_event->event_id.tid = perf_event_tid(event, task);
+ task_event->event_id.ptid = perf_event_tid(event, current);
+
+ perf_output_put(&handle, task_event->event_id);
+
+ perf_event__output_id_sample(event, &handle, &sample);
+
+ perf_output_end(&handle);
+out:
+ task_event->event_id.header.size = size;
+}
+
+static int perf_event_task_match(struct perf_event *event)
+{
+ if (event->state < PERF_EVENT_STATE_INACTIVE)
+ return 0;
+
+ if (!event_filter_match(event))
+ return 0;
+
+ if (event->attr.comm || event->attr.mmap ||
+ event->attr.mmap_data || event->attr.task)
+ return 1;
+
+ return 0;
+}
+
+static void perf_event_task_ctx(struct perf_event_context *ctx,
+ struct perf_task_event *task_event)
+{
+ struct perf_event *event;
+
+ list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
+ if (perf_event_task_match(event))
+ perf_event_task_output(event, task_event);
+ }
+}
+
+static void perf_event_task_event(struct perf_task_event *task_event)
+{
+ struct perf_cpu_context *cpuctx;
+ struct perf_event_context *ctx;
+ struct pmu *pmu;
+ int ctxn;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(pmu, &pmus, entry) {
+ cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
+ if (cpuctx->active_pmu != pmu)
+ goto next;
+ perf_event_task_ctx(&cpuctx->ctx, task_event);
+
+ ctx = task_event->task_ctx;
+ if (!ctx) {
+ ctxn = pmu->task_ctx_nr;
+ if (ctxn < 0)
+ goto next;
+ ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
+ }
+ if (ctx)
+ perf_event_task_ctx(ctx, task_event);
+next:
+ put_cpu_ptr(pmu->pmu_cpu_context);
+ }
+ rcu_read_unlock();
+}
+
+static void perf_event_task(struct task_struct *task,
+ struct perf_event_context *task_ctx,
+ int new)
+{
+ struct perf_task_event task_event;
+
+ if (!atomic_read(&nr_comm_events) &&
+ !atomic_read(&nr_mmap_events) &&
+ !atomic_read(&nr_task_events))
+ return;
+
+ task_event = (struct perf_task_event){
+ .task = task,
+ .task_ctx = task_ctx,
+ .event_id = {
+ .header = {
+ .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
+ .misc = 0,
+ .size = sizeof(task_event.event_id),
+ },
+ /* .pid */
+ /* .ppid */
+ /* .tid */
+ /* .ptid */
+ .time = perf_clock(),
+ },
+ };
+
+ perf_event_task_event(&task_event);
+}
+
+void perf_event_fork(struct task_struct *task)
+{
+ perf_event_task(task, NULL, 1);
+}
+
+/*
+ * comm tracking
+ */
+
+struct perf_comm_event {
+ struct task_struct *task;
+ char *comm;
+ int comm_size;
+
+ struct {
+ struct perf_event_header header;
+
+ u32 pid;
+ u32 tid;
+ } event_id;
+};
+
+static void perf_event_comm_output(struct perf_event *event,
+ struct perf_comm_event *comm_event)
+{
+ struct perf_output_handle handle;
+ struct perf_sample_data sample;
+ int size = comm_event->event_id.header.size;
+ int ret;
+
+ perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
+ ret = perf_output_begin(&handle, event,
+ comm_event->event_id.header.size, 0, 0);
+
+ if (ret)
+ goto out;
+
+ comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
+ comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
+
+ perf_output_put(&handle, comm_event->event_id);
+ perf_output_copy(&handle, comm_event->comm,
+ comm_event->comm_size);
+
+ perf_event__output_id_sample(event, &handle, &sample);
+
+ perf_output_end(&handle);
+out:
+ comm_event->event_id.header.size = size;
+}
+
+static int perf_event_comm_match(struct perf_event *event)
+{
+ if (event->state < PERF_EVENT_STATE_INACTIVE)
+ return 0;
+
+ if (!event_filter_match(event))
+ return 0;
+
+ if (event->attr.comm)
+ return 1;
+
+ return 0;
+}
+
+static void perf_event_comm_ctx(struct perf_event_context *ctx,
+ struct perf_comm_event *comm_event)
+{
+ struct perf_event *event;
+
+ list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
+ if (perf_event_comm_match(event))
+ perf_event_comm_output(event, comm_event);
+ }
+}
+
+static void perf_event_comm_event(struct perf_comm_event *comm_event)
+{
+ struct perf_cpu_context *cpuctx;
+ struct perf_event_context *ctx;
+ char comm[TASK_COMM_LEN];
+ unsigned int size;
+ struct pmu *pmu;
+ int ctxn;
+
+ memset(comm, 0, sizeof(comm));
+ strlcpy(comm, comm_event->task->comm, sizeof(comm));
+ size = ALIGN(strlen(comm)+1, sizeof(u64));
+
+ comm_event->comm = comm;
+ comm_event->comm_size = size;
+
+ comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
+ rcu_read_lock();
+ list_for_each_entry_rcu(pmu, &pmus, entry) {
+ cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
+ if (cpuctx->active_pmu != pmu)
+ goto next;
+ perf_event_comm_ctx(&cpuctx->ctx, comm_event);
+
+ ctxn = pmu->task_ctx_nr;
+ if (ctxn < 0)
+ goto next;
+
+ ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
+ if (ctx)
+ perf_event_comm_ctx(ctx, comm_event);
+next:
+ put_cpu_ptr(pmu->pmu_cpu_context);
+ }
+ rcu_read_unlock();
+}
+
+void perf_event_comm(struct task_struct *task)
+{
+ struct perf_comm_event comm_event;
+ struct perf_event_context *ctx;
+ int ctxn;
+
+ for_each_task_context_nr(ctxn) {
+ ctx = task->perf_event_ctxp[ctxn];
+ if (!ctx)
+ continue;
+
+ perf_event_enable_on_exec(ctx);
+ }
+
+ if (!atomic_read(&nr_comm_events))
+ return;
+
+ comm_event = (struct perf_comm_event){
+ .task = task,
+ /* .comm */
+ /* .comm_size */
+ .event_id = {
+ .header = {
+ .type = PERF_RECORD_COMM,
+ .misc = 0,
+ /* .size */
+ },
+ /* .pid */
+ /* .tid */
+ },
+ };
+
+ perf_event_comm_event(&comm_event);
+}
+
+/*
+ * mmap tracking
+ */
+
+struct perf_mmap_event {
+ struct vm_area_struct *vma;
+
+ const char *file_name;
+ int file_size;
+
+ struct {
+ struct perf_event_header header;
+
+ u32 pid;
+ u32 tid;
+ u64 start;
+ u64 len;
+ u64 pgoff;
+ } event_id;
+};
+
+static void perf_event_mmap_output(struct perf_event *event,
+ struct perf_mmap_event *mmap_event)
+{
+ struct perf_output_handle handle;
+ struct perf_sample_data sample;
+ int size = mmap_event->event_id.header.size;
+ int ret;
+
+ perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
+ ret = perf_output_begin(&handle, event,
+ mmap_event->event_id.header.size, 0, 0);
+ if (ret)
+ goto out;
+
+ mmap_event->event_id.pid = perf_event_pid(event, current);
+ mmap_event->event_id.tid = perf_event_tid(event, current);
+
+ perf_output_put(&handle, mmap_event->event_id);
+ perf_output_copy(&handle, mmap_event->file_name,
+ mmap_event->file_size);
+
+ perf_event__output_id_sample(event, &handle, &sample);
+
+ perf_output_end(&handle);
+out:
+ mmap_event->event_id.header.size = size;
+}
+
+static int perf_event_mmap_match(struct perf_event *event,
+ struct perf_mmap_event *mmap_event,
+ int executable)
+{
+ if (event->state < PERF_EVENT_STATE_INACTIVE)
+ return 0;
+
+ if (!event_filter_match(event))
+ return 0;
+
+ if ((!executable && event->attr.mmap_data) ||
+ (executable && event->attr.mmap))
+ return 1;
+
+ return 0;
+}
+
+static void perf_event_mmap_ctx(struct perf_event_context *ctx,
+ struct perf_mmap_event *mmap_event,
+ int executable)
+{
+ struct perf_event *event;
+
+ list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
+ if (perf_event_mmap_match(event, mmap_event, executable))
+ perf_event_mmap_output(event, mmap_event);
+ }
+}
+
+static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
+{
+ struct perf_cpu_context *cpuctx;
+ struct perf_event_context *ctx;
+ struct vm_area_struct *vma = mmap_event->vma;
+ struct file *file = vma->vm_file;
+ unsigned int size;
+ char tmp[16];
+ char *buf = NULL;
+ const char *name;
+ struct pmu *pmu;
+ int ctxn;
+
+ memset(tmp, 0, sizeof(tmp));
+
+ if (file) {
+ /*
+ * d_path works from the end of the buffer backwards, so we
+ * need to add enough zero bytes after the string to handle
+ * the 64bit alignment we do later.
+ */
+ buf = kzalloc(PATH_MAX + sizeof(u64), GFP_KERNEL);
+ if (!buf) {
+ name = strncpy(tmp, "//enomem", sizeof(tmp));
+ goto got_name;
+ }
+ name = d_path(&file->f_path, buf, PATH_MAX);
+ if (IS_ERR(name)) {
+ name = strncpy(tmp, "//toolong", sizeof(tmp));
+ goto got_name;
+ }
+ } else {
+ if (arch_vma_name(mmap_event->vma)) {
+ name = strncpy(tmp, arch_vma_name(mmap_event->vma),
+ sizeof(tmp));
+ goto got_name;
+ }
+
+ if (!vma->vm_mm) {
+ name = strncpy(tmp, "[vdso]", sizeof(tmp));
+ goto got_name;
+ } else if (vma->vm_start <= vma->vm_mm->start_brk &&
+ vma->vm_end >= vma->vm_mm->brk) {
+ name = strncpy(tmp, "[heap]", sizeof(tmp));
+ goto got_name;
+ } else if (vma->vm_start <= vma->vm_mm->start_stack &&
+ vma->vm_end >= vma->vm_mm->start_stack) {
+ name = strncpy(tmp, "[stack]", sizeof(tmp));
+ goto got_name;
+ }
+
+ name = strncpy(tmp, "//anon", sizeof(tmp));
+ goto got_name;
+ }
+
+got_name:
+ size = ALIGN(strlen(name)+1, sizeof(u64));
+
+ mmap_event->file_name = name;
+ mmap_event->file_size = size;
+
+ mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(pmu, &pmus, entry) {
+ cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
+ if (cpuctx->active_pmu != pmu)
+ goto next;
+ perf_event_mmap_ctx(&cpuctx->ctx, mmap_event,
+ vma->vm_flags & VM_EXEC);
+
+ ctxn = pmu->task_ctx_nr;
+ if (ctxn < 0)
+ goto next;
+
+ ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
+ if (ctx) {
+ perf_event_mmap_ctx(ctx, mmap_event,
+ vma->vm_flags & VM_EXEC);
+ }
+next:
+ put_cpu_ptr(pmu->pmu_cpu_context);
+ }
+ rcu_read_unlock();
+
+ kfree(buf);
+}
+
+void perf_event_mmap(struct vm_area_struct *vma)
+{
+ struct perf_mmap_event mmap_event;
+
+ if (!atomic_read(&nr_mmap_events))
+ return;
+
+ mmap_event = (struct perf_mmap_event){
+ .vma = vma,
+ /* .file_name */
+ /* .file_size */
+ .event_id = {
+ .header = {
+ .type = PERF_RECORD_MMAP,
+ .misc = PERF_RECORD_MISC_USER,
+ /* .size */
+ },
+ /* .pid */
+ /* .tid */
+ .start = vma->vm_start,
+ .len = vma->vm_end - vma->vm_start,
+ .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
+ },
+ };
+
+ perf_event_mmap_event(&mmap_event);
+}
+
+/*
+ * IRQ throttle logging
+ */
+
+static void perf_log_throttle(struct perf_event *event, int enable)
+{
+ struct perf_output_handle handle;
+ struct perf_sample_data sample;
+ int ret;
+
+ struct {
+ struct perf_event_header header;
+ u64 time;
+ u64 id;
+ u64 stream_id;
+ } throttle_event = {
+ .header = {
+ .type = PERF_RECORD_THROTTLE,
+ .misc = 0,
+ .size = sizeof(throttle_event),
+ },
+ .time = perf_clock(),
+ .id = primary_event_id(event),
+ .stream_id = event->id,
+ };
+
+ if (enable)
+ throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
+
+ perf_event_header__init_id(&throttle_event.header, &sample, event);
+
+ ret = perf_output_begin(&handle, event,
+ throttle_event.header.size, 1, 0);
+ if (ret)
+ return;
+
+ perf_output_put(&handle, throttle_event);
+ perf_event__output_id_sample(event, &handle, &sample);
+ perf_output_end(&handle);
+}
+
+/*
+ * Generic event overflow handling, sampling.
+ */
+
+static int __perf_event_overflow(struct perf_event *event, int nmi,
+ int throttle, struct perf_sample_data *data,
+ struct pt_regs *regs)
+{
+ int events = atomic_read(&event->event_limit);
+ struct hw_perf_event *hwc = &event->hw;
+ int ret = 0;
+
+ /*
+ * Non-sampling counters might still use the PMI to fold short
+ * hardware counters, ignore those.
+ */
+ if (unlikely(!is_sampling_event(event)))
+ return 0;
+
+ if (unlikely(hwc->interrupts >= max_samples_per_tick)) {
+ if (throttle) {
+ hwc->interrupts = MAX_INTERRUPTS;
+ perf_log_throttle(event, 0);
+ ret = 1;
+ }
+ } else
+ hwc->interrupts++;
+
+ if (event->attr.freq) {
+ u64 now = perf_clock();
+ s64 delta = now - hwc->freq_time_stamp;
+
+ hwc->freq_time_stamp = now;
+
+ if (delta > 0 && delta < 2*TICK_NSEC)
+ perf_adjust_period(event, delta, hwc->last_period);
+ }
+
+ /*
+ * XXX event_limit might not quite work as expected on inherited
+ * events
+ */
+
+ event->pending_kill = POLL_IN;
+ if (events && atomic_dec_and_test(&event->event_limit)) {
+ ret = 1;
+ event->pending_kill = POLL_HUP;
+ if (nmi) {
+ event->pending_disable = 1;
+ irq_work_queue(&event->pending);
+ } else
+ perf_event_disable(event);
+ }
+
+ if (event->overflow_handler)
+ event->overflow_handler(event, nmi, data, regs);
+ else
+ perf_event_output(event, nmi, data, regs);
+
+ return ret;
+}
+
+int perf_event_overflow(struct perf_event *event, int nmi,
+ struct perf_sample_data *data,
+ struct pt_regs *regs)
+{
+ return __perf_event_overflow(event, nmi, 1, data, regs);
+}
+
+/*
+ * Generic software event infrastructure
+ */
+
+struct swevent_htable {
+ struct swevent_hlist *swevent_hlist;
+ struct mutex hlist_mutex;
+ int hlist_refcount;
+
+ /* Recursion avoidance in each contexts */
+ int recursion[PERF_NR_CONTEXTS];
+};
+
+static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
+
+/*
+ * We directly increment event->count and keep a second value in
+ * event->hw.period_left to count intervals. This period event
+ * is kept in the range [-sample_period, 0] so that we can use the
+ * sign as trigger.
+ */
+
+static u64 perf_swevent_set_period(struct perf_event *event)
+{
+ struct hw_perf_event *hwc = &event->hw;
+ u64 period = hwc->last_period;
+ u64 nr, offset;
+ s64 old, val;
+
+ hwc->last_period = hwc->sample_period;
+
+again:
+ old = val = local64_read(&hwc->period_left);
+ if (val < 0)
+ return 0;
+
+ nr = div64_u64(period + val, period);
+ offset = nr * period;
+ val -= offset;
+ if (local64_cmpxchg(&hwc->period_left, old, val) != old)
+ goto again;
+
+ return nr;
+}
+
+static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
+ int nmi, struct perf_sample_data *data,
+ struct pt_regs *regs)
+{
+ struct hw_perf_event *hwc = &event->hw;
+ int throttle = 0;
+
+ data->period = event->hw.last_period;
+ if (!overflow)
+ overflow = perf_swevent_set_period(event);
+
+ if (hwc->interrupts == MAX_INTERRUPTS)
+ return;
+
+ for (; overflow; overflow--) {
+ if (__perf_event_overflow(event, nmi, throttle,
+ data, regs)) {
+ /*
+ * We inhibit the overflow from happening when
+ * hwc->interrupts == MAX_INTERRUPTS.
+ */
+ break;
+ }
+ throttle = 1;
+ }
+}
+
+static void perf_swevent_event(struct perf_event *event, u64 nr,
+ int nmi, struct perf_sample_data *data,
+ struct pt_regs *regs)
+{
+ struct hw_perf_event *hwc = &event->hw;
+
+ local64_add(nr, &event->count);
+
+ if (!regs)
+ return;
+
+ if (!is_sampling_event(event))
+ return;
+
+ if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
+ return perf_swevent_overflow(event, 1, nmi, data, regs);
+
+ if (local64_add_negative(nr, &hwc->period_left))
+ return;
+
+ perf_swevent_overflow(event, 0, nmi, data, regs);
+}
+
+static int perf_exclude_event(struct perf_event *event,
+ struct pt_regs *regs)
+{
+ if (event->hw.state & PERF_HES_STOPPED)
+ return 1;
+
+ if (regs) {
+ if (event->attr.exclude_user && user_mode(regs))
+ return 1;
+
+ if (event->attr.exclude_kernel && !user_mode(regs))
+ return 1;
+ }
+
+ return 0;
+}
+
+static int perf_swevent_match(struct perf_event *event,
+ enum perf_type_id type,
+ u32 event_id,
+ struct perf_sample_data *data,
+ struct pt_regs *regs)
+{
+ if (event->attr.type != type)
+ return 0;
+
+ if (event->attr.config != event_id)
+ return 0;
+
+ if (perf_exclude_event(event, regs))
+ return 0;
+
+ return 1;
+}
+
+static inline u64 swevent_hash(u64 type, u32 event_id)
+{
+ u64 val = event_id | (type << 32);
+
+ return hash_64(val, SWEVENT_HLIST_BITS);
+}
+
+static inline struct hlist_head *
+__find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
+{
+ u64 hash = swevent_hash(type, event_id);
+
+ return &hlist->heads[hash];
+}
+
+/* For the read side: events when they trigger */
+static inline struct hlist_head *
+find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
+{
+ struct swevent_hlist *hlist;
+
+ hlist = rcu_dereference(swhash->swevent_hlist);
+ if (!hlist)
+ return NULL;
+
+ return __find_swevent_head(hlist, type, event_id);
+}
+
+/* For the event head insertion and removal in the hlist */
+static inline struct hlist_head *
+find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
+{
+ struct swevent_hlist *hlist;
+ u32 event_id = event->attr.config;
+ u64 type = event->attr.type;
+
+ /*
+ * Event scheduling is always serialized against hlist allocation
+ * and release. Which makes the protected version suitable here.
+ * The context lock guarantees that.
+ */
+ hlist = rcu_dereference_protected(swhash->swevent_hlist,
+ lockdep_is_held(&event->ctx->lock));
+ if (!hlist)
+ return NULL;
+
+ return __find_swevent_head(hlist, type, event_id);
+}
+
+static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
+ u64 nr, int nmi,
+ struct perf_sample_data *data,
+ struct pt_regs *regs)
+{
+ struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
+ struct perf_event *event;
+ struct hlist_node *node;
+ struct hlist_head *head;
+
+ rcu_read_lock();
+ head = find_swevent_head_rcu(swhash, type, event_id);
+ if (!head)
+ goto end;
+
+ hlist_for_each_entry_rcu(event, node, head, hlist_entry) {
+ if (perf_swevent_match(event, type, event_id, data, regs))
+ perf_swevent_event(event, nr, nmi, data, regs);
+ }
+end:
+ rcu_read_unlock();
+}
+
+int perf_swevent_get_recursion_context(void)
+{
+ struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
+
+ return get_recursion_context(swhash->recursion);
+}
+EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
+
+inline void perf_swevent_put_recursion_context(int rctx)
+{
+ struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
+
+ put_recursion_context(swhash->recursion, rctx);
+}
+
+void __perf_sw_event(u32 event_id, u64 nr, int nmi,
+ struct pt_regs *regs, u64 addr)
+{
+ struct perf_sample_data data;
+ int rctx;
+
+ preempt_disable_notrace();
+ rctx = perf_swevent_get_recursion_context();
+ if (rctx < 0)
+ return;
+
+ perf_sample_data_init(&data, addr);
+
+ do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, nmi, &data, regs);
+
+ perf_swevent_put_recursion_context(rctx);
+ preempt_enable_notrace();
+}
+
+static void perf_swevent_read(struct perf_event *event)
+{
+}
+
+static int perf_swevent_add(struct perf_event *event, int flags)
+{
+ struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
+ struct hw_perf_event *hwc = &event->hw;
+ struct hlist_head *head;
+
+ if (is_sampling_event(event)) {
+ hwc->last_period = hwc->sample_period;
+ perf_swevent_set_period(event);
+ }
+
+ hwc->state = !(flags & PERF_EF_START);
+
+ head = find_swevent_head(swhash, event);
+ if (WARN_ON_ONCE(!head))
+ return -EINVAL;
+
+ hlist_add_head_rcu(&event->hlist_entry, head);
+
+ return 0;
+}
+
+static void perf_swevent_del(struct perf_event *event, int flags)
+{
+ hlist_del_rcu(&event->hlist_entry);
+}
+
+static void perf_swevent_start(struct perf_event *event, int flags)
+{
+ event->hw.state = 0;
+}
+
+static void perf_swevent_stop(struct perf_event *event, int flags)
+{
+ event->hw.state = PERF_HES_STOPPED;
+}
+
+/* Deref the hlist from the update side */
+static inline struct swevent_hlist *
+swevent_hlist_deref(struct swevent_htable *swhash)
+{
+ return rcu_dereference_protected(swhash->swevent_hlist,
+ lockdep_is_held(&swhash->hlist_mutex));
+}
+
- static void swevent_hlist_release_rcu(struct rcu_head *rcu_head)
- {
- struct swevent_hlist *hlist;
-
- hlist = container_of(rcu_head, struct swevent_hlist, rcu_head);
- kfree(hlist);
- }
-
+static void swevent_hlist_release(struct swevent_htable *swhash)
+{
+ struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
+
+ if (!hlist)
+ return;
+
+ rcu_assign_pointer(swhash->swevent_hlist, NULL);
- call_rcu(&hlist->rcu_head, swevent_hlist_release_rcu);
++ kfree_rcu(hlist, rcu_head);
+}
+
+static void swevent_hlist_put_cpu(struct perf_event *event, int cpu)
+{
+ struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
+
+ mutex_lock(&swhash->hlist_mutex);
+
+ if (!--swhash->hlist_refcount)
+ swevent_hlist_release(swhash);
+
+ mutex_unlock(&swhash->hlist_mutex);
+}
+
+static void swevent_hlist_put(struct perf_event *event)
+{
+ int cpu;
+
+ if (event->cpu != -1) {
+ swevent_hlist_put_cpu(event, event->cpu);
+ return;
+ }
+
+ for_each_possible_cpu(cpu)
+ swevent_hlist_put_cpu(event, cpu);
+}
+
+static int swevent_hlist_get_cpu(struct perf_event *event, int cpu)
+{
+ struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
+ int err = 0;
+
+ mutex_lock(&swhash->hlist_mutex);
+
+ if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
+ struct swevent_hlist *hlist;
+
+ hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
+ if (!hlist) {
+ err = -ENOMEM;
+ goto exit;
+ }
+ rcu_assign_pointer(swhash->swevent_hlist, hlist);
+ }
+ swhash->hlist_refcount++;
+exit:
+ mutex_unlock(&swhash->hlist_mutex);
+
+ return err;
+}
+
+static int swevent_hlist_get(struct perf_event *event)
+{
+ int err;
+ int cpu, failed_cpu;
+
+ if (event->cpu != -1)
+ return swevent_hlist_get_cpu(event, event->cpu);
+
+ get_online_cpus();
+ for_each_possible_cpu(cpu) {
+ err = swevent_hlist_get_cpu(event, cpu);
+ if (err) {
+ failed_cpu = cpu;
+ goto fail;
+ }
+ }
+ put_online_cpus();
+
+ return 0;
+fail:
+ for_each_possible_cpu(cpu) {
+ if (cpu == failed_cpu)
+ break;
+ swevent_hlist_put_cpu(event, cpu);
+ }
+
+ put_online_cpus();
+ return err;
+}
+
+struct jump_label_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
+
+static void sw_perf_event_destroy(struct perf_event *event)
+{
+ u64 event_id = event->attr.config;
+
+ WARN_ON(event->parent);
+
+ jump_label_dec(&perf_swevent_enabled[event_id]);
+ swevent_hlist_put(event);
+}
+
+static int perf_swevent_init(struct perf_event *event)
+{
+ int event_id = event->attr.config;
+
+ if (event->attr.type != PERF_TYPE_SOFTWARE)
+ return -ENOENT;
+
+ switch (event_id) {
+ case PERF_COUNT_SW_CPU_CLOCK:
+ case PERF_COUNT_SW_TASK_CLOCK:
+ return -ENOENT;
+
+ default:
+ break;
+ }
+
+ if (event_id >= PERF_COUNT_SW_MAX)
+ return -ENOENT;
+
+ if (!event->parent) {
+ int err;
+
+ err = swevent_hlist_get(event);
+ if (err)
+ return err;
+
+ jump_label_inc(&perf_swevent_enabled[event_id]);
+ event->destroy = sw_perf_event_destroy;
+ }
+
+ return 0;
+}
+
+static struct pmu perf_swevent = {
+ .task_ctx_nr = perf_sw_context,
+
+ .event_init = perf_swevent_init,
+ .add = perf_swevent_add,
+ .del = perf_swevent_del,
+ .start = perf_swevent_start,
+ .stop = perf_swevent_stop,
+ .read = perf_swevent_read,
+};
+
+#ifdef CONFIG_EVENT_TRACING
+
+static int perf_tp_filter_match(struct perf_event *event,
+ struct perf_sample_data *data)
+{
+ void *record = data->raw->data;
+
+ if (likely(!event->filter) || filter_match_preds(event->filter, record))
+ return 1;
+ return 0;
+}
+
+static int perf_tp_event_match(struct perf_event *event,
+ struct perf_sample_data *data,
+ struct pt_regs *regs)
+{
+ if (event->hw.state & PERF_HES_STOPPED)
+ return 0;
+ /*
+ * All tracepoints are from kernel-space.
+ */
+ if (event->attr.exclude_kernel)
+ return 0;
+
+ if (!perf_tp_filter_match(event, data))
+ return 0;
+
+ return 1;
+}
+
+void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
+ struct pt_regs *regs, struct hlist_head *head, int rctx)
+{
+ struct perf_sample_data data;
+ struct perf_event *event;
+ struct hlist_node *node;
+
+ struct perf_raw_record raw = {
+ .size = entry_size,
+ .data = record,
+ };
+
+ perf_sample_data_init(&data, addr);
+ data.raw = &raw;
+
+ hlist_for_each_entry_rcu(event, node, head, hlist_entry) {
+ if (perf_tp_event_match(event, &data, regs))
+ perf_swevent_event(event, count, 1, &data, regs);
+ }
+
+ perf_swevent_put_recursion_context(rctx);
+}
+EXPORT_SYMBOL_GPL(perf_tp_event);
+
+static void tp_perf_event_destroy(struct perf_event *event)
+{
+ perf_trace_destroy(event);
+}
+
+static int perf_tp_event_init(struct perf_event *event)
+{
+ int err;
+
+ if (event->attr.type != PERF_TYPE_TRACEPOINT)
+ return -ENOENT;
+
+ err = perf_trace_init(event);
+ if (err)
+ return err;
+
+ event->destroy = tp_perf_event_destroy;
+
+ return 0;
+}
+
+static struct pmu perf_tracepoint = {
+ .task_ctx_nr = perf_sw_context,
+
+ .event_init = perf_tp_event_init,
+ .add = perf_trace_add,
+ .del = perf_trace_del,
+ .start = perf_swevent_start,
+ .stop = perf_swevent_stop,
+ .read = perf_swevent_read,
+};
+
+static inline void perf_tp_register(void)
+{
+ perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
+}
+
+static int perf_event_set_filter(struct perf_event *event, void __user *arg)
+{
+ char *filter_str;
+ int ret;
+
+ if (event->attr.type != PERF_TYPE_TRACEPOINT)
+ return -EINVAL;
+
+ filter_str = strndup_user(arg, PAGE_SIZE);
+ if (IS_ERR(filter_str))
+ return PTR_ERR(filter_str);
+
+ ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
+
+ kfree(filter_str);
+ return ret;
+}
+
+static void perf_event_free_filter(struct perf_event *event)
+{
+ ftrace_profile_free_filter(event);
+}
+
+#else
+
+static inline void perf_tp_register(void)
+{
+}
+
+static int perf_event_set_filter(struct perf_event *event, void __user *arg)
+{
+ return -ENOENT;
+}
+
+static void perf_event_free_filter(struct perf_event *event)
+{
+}
+
+#endif /* CONFIG_EVENT_TRACING */
+
+#ifdef CONFIG_HAVE_HW_BREAKPOINT
+void perf_bp_event(struct perf_event *bp, void *data)
+{
+ struct perf_sample_data sample;
+ struct pt_regs *regs = data;
+
+ perf_sample_data_init(&sample, bp->attr.bp_addr);
+
+ if (!bp->hw.state && !perf_exclude_event(bp, regs))
+ perf_swevent_event(bp, 1, 1, &sample, regs);
+}
+#endif
+
+/*
+ * hrtimer based swevent callback
+ */
+
+static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
+{
+ enum hrtimer_restart ret = HRTIMER_RESTART;
+ struct perf_sample_data data;
+ struct pt_regs *regs;
+ struct perf_event *event;
+ u64 period;
+
+ event = container_of(hrtimer, struct perf_event, hw.hrtimer);
+
+ if (event->state != PERF_EVENT_STATE_ACTIVE)
+ return HRTIMER_NORESTART;
+
+ event->pmu->read(event);
+
+ perf_sample_data_init(&data, 0);
+ data.period = event->hw.last_period;
+ regs = get_irq_regs();
+
+ if (regs && !perf_exclude_event(event, regs)) {
+ if (!(event->attr.exclude_idle && current->pid == 0))
+ if (perf_event_overflow(event, 0, &data, regs))
+ ret = HRTIMER_NORESTART;
+ }
+
+ period = max_t(u64, 10000, event->hw.sample_period);
+ hrtimer_forward_now(hrtimer, ns_to_ktime(period));
+
+ return ret;
+}
+
+static void perf_swevent_start_hrtimer(struct perf_event *event)
+{
+ struct hw_perf_event *hwc = &event->hw;
+ s64 period;
+
+ if (!is_sampling_event(event))
+ return;
+
+ period = local64_read(&hwc->period_left);
+ if (period) {
+ if (period < 0)
+ period = 10000;
+
+ local64_set(&hwc->period_left, 0);
+ } else {
+ period = max_t(u64, 10000, hwc->sample_period);
+ }
+ __hrtimer_start_range_ns(&hwc->hrtimer,
+ ns_to_ktime(period), 0,
+ HRTIMER_MODE_REL_PINNED, 0);
+}
+
+static void perf_swevent_cancel_hrtimer(struct perf_event *event)
+{
+ struct hw_perf_event *hwc = &event->hw;
+
+ if (is_sampling_event(event)) {
+ ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
+ local64_set(&hwc->period_left, ktime_to_ns(remaining));
+
+ hrtimer_cancel(&hwc->hrtimer);
+ }
+}
+
+static void perf_swevent_init_hrtimer(struct perf_event *event)
+{
+ struct hw_perf_event *hwc = &event->hw;
+
+ if (!is_sampling_event(event))
+ return;
+
+ hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+ hwc->hrtimer.function = perf_swevent_hrtimer;
+
+ /*
+ * Since hrtimers have a fixed rate, we can do a static freq->period
+ * mapping and avoid the whole period adjust feedback stuff.
+ */
+ if (event->attr.freq) {
+ long freq = event->attr.sample_freq;
+
+ event->attr.sample_period = NSEC_PER_SEC / freq;
+ hwc->sample_period = event->attr.sample_period;
+ local64_set(&hwc->period_left, hwc->sample_period);
+ event->attr.freq = 0;
+ }
+}
+
+/*
+ * Software event: cpu wall time clock
+ */
+
+static void cpu_clock_event_update(struct perf_event *event)
+{
+ s64 prev;
+ u64 now;
+
+ now = local_clock();
+ prev = local64_xchg(&event->hw.prev_count, now);
+ local64_add(now - prev, &event->count);
+}
+
+static void cpu_clock_event_start(struct perf_event *event, int flags)
+{
+ local64_set(&event->hw.prev_count, local_clock());
+ perf_swevent_start_hrtimer(event);
+}
+
+static void cpu_clock_event_stop(struct perf_event *event, int flags)
+{
+ perf_swevent_cancel_hrtimer(event);
+ cpu_clock_event_update(event);
+}
+
+static int cpu_clock_event_add(struct perf_event *event, int flags)
+{
+ if (flags & PERF_EF_START)
+ cpu_clock_event_start(event, flags);
+
+ return 0;
+}
+
+static void cpu_clock_event_del(struct perf_event *event, int flags)
+{
+ cpu_clock_event_stop(event, flags);
+}
+
+static void cpu_clock_event_read(struct perf_event *event)
+{
+ cpu_clock_event_update(event);
+}
+
+static int cpu_clock_event_init(struct perf_event *event)
+{
+ if (event->attr.type != PERF_TYPE_SOFTWARE)
+ return -ENOENT;
+
+ if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
+ return -ENOENT;
+
+ perf_swevent_init_hrtimer(event);
+
+ return 0;
+}
+
+static struct pmu perf_cpu_clock = {
+ .task_ctx_nr = perf_sw_context,
+
+ .event_init = cpu_clock_event_init,
+ .add = cpu_clock_event_add,
+ .del = cpu_clock_event_del,
+ .start = cpu_clock_event_start,
+ .stop = cpu_clock_event_stop,
+ .read = cpu_clock_event_read,
+};
+
+/*
+ * Software event: task time clock
+ */
+
+static void task_clock_event_update(struct perf_event *event, u64 now)
+{
+ u64 prev;
+ s64 delta;
+
+ prev = local64_xchg(&event->hw.prev_count, now);
+ delta = now - prev;
+ local64_add(delta, &event->count);
+}
+
+static void task_clock_event_start(struct perf_event *event, int flags)
+{
+ local64_set(&event->hw.prev_count, event->ctx->time);
+ perf_swevent_start_hrtimer(event);
+}
+
+static void task_clock_event_stop(struct perf_event *event, int flags)
+{
+ perf_swevent_cancel_hrtimer(event);
+ task_clock_event_update(event, event->ctx->time);
+}
+
+static int task_clock_event_add(struct perf_event *event, int flags)
+{
+ if (flags & PERF_EF_START)
+ task_clock_event_start(event, flags);
+
+ return 0;
+}
+
+static void task_clock_event_del(struct perf_event *event, int flags)
+{
+ task_clock_event_stop(event, PERF_EF_UPDATE);
+}
+
+static void task_clock_event_read(struct perf_event *event)
+{
+ u64 now = perf_clock();
+ u64 delta = now - event->ctx->timestamp;
+ u64 time = event->ctx->time + delta;
+
+ task_clock_event_update(event, time);
+}
+
+static int task_clock_event_init(struct perf_event *event)
+{
+ if (event->attr.type != PERF_TYPE_SOFTWARE)
+ return -ENOENT;
+
+ if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
+ return -ENOENT;
+
+ perf_swevent_init_hrtimer(event);
+
+ return 0;
+}
+
+static struct pmu perf_task_clock = {
+ .task_ctx_nr = perf_sw_context,
+
+ .event_init = task_clock_event_init,
+ .add = task_clock_event_add,
+ .del = task_clock_event_del,
+ .start = task_clock_event_start,
+ .stop = task_clock_event_stop,
+ .read = task_clock_event_read,
+};
+
+static void perf_pmu_nop_void(struct pmu *pmu)
+{
+}
+
+static int perf_pmu_nop_int(struct pmu *pmu)
+{
+ return 0;
+}
+
+static void perf_pmu_start_txn(struct pmu *pmu)
+{
+ perf_pmu_disable(pmu);
+}
+
+static int perf_pmu_commit_txn(struct pmu *pmu)
+{
+ perf_pmu_enable(pmu);
+ return 0;
+}
+
+static void perf_pmu_cancel_txn(struct pmu *pmu)
+{
+ perf_pmu_enable(pmu);
+}
+
+/*
+ * Ensures all contexts with the same task_ctx_nr have the same
+ * pmu_cpu_context too.
+ */
+static void *find_pmu_context(int ctxn)
+{
+ struct pmu *pmu;
+
+ if (ctxn < 0)
+ return NULL;
+
+ list_for_each_entry(pmu, &pmus, entry) {
+ if (pmu->task_ctx_nr == ctxn)
+ return pmu->pmu_cpu_context;
+ }
+
+ return NULL;
+}
+
+static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu)
+{
+ int cpu;
+
+ for_each_possible_cpu(cpu) {
+ struct perf_cpu_context *cpuctx;
+
+ cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
+
+ if (cpuctx->active_pmu == old_pmu)
+ cpuctx->active_pmu = pmu;
+ }
+}
+
+static void free_pmu_context(struct pmu *pmu)
+{
+ struct pmu *i;
+
+ mutex_lock(&pmus_lock);
+ /*
+ * Like a real lame refcount.
+ */
+ list_for_each_entry(i, &pmus, entry) {
+ if (i->pmu_cpu_context == pmu->pmu_cpu_context) {
+ update_pmu_context(i, pmu);
+ goto out;
+ }
+ }
+
+ free_percpu(pmu->pmu_cpu_context);
+out:
+ mutex_unlock(&pmus_lock);
+}
+static struct idr pmu_idr;
+
+static ssize_t
+type_show(struct device *dev, struct device_attribute *attr, char *page)
+{
+ struct pmu *pmu = dev_get_drvdata(dev);
+
+ return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
+}
+
+static struct device_attribute pmu_dev_attrs[] = {
+ __ATTR_RO(type),
+ __ATTR_NULL,
+};
+
+static int pmu_bus_running;
+static struct bus_type pmu_bus = {
+ .name = "event_source",
+ .dev_attrs = pmu_dev_attrs,
+};
+
+static void pmu_dev_release(struct device *dev)
+{
+ kfree(dev);
+}
+
+static int pmu_dev_alloc(struct pmu *pmu)
+{
+ int ret = -ENOMEM;
+
+ pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
+ if (!pmu->dev)
+ goto out;
+
+ device_initialize(pmu->dev);
+ ret = dev_set_name(pmu->dev, "%s", pmu->name);
+ if (ret)
+ goto free_dev;
+
+ dev_set_drvdata(pmu->dev, pmu);
+ pmu->dev->bus = &pmu_bus;
+ pmu->dev->release = pmu_dev_release;
+ ret = device_add(pmu->dev);
+ if (ret)
+ goto free_dev;
+
+out:
+ return ret;
+
+free_dev:
+ put_device(pmu->dev);
+ goto out;
+}
+
+static struct lock_class_key cpuctx_mutex;
+
+int perf_pmu_register(struct pmu *pmu, char *name, int type)
+{
+ int cpu, ret;
+
+ mutex_lock(&pmus_lock);
+ ret = -ENOMEM;
+ pmu->pmu_disable_count = alloc_percpu(int);
+ if (!pmu->pmu_disable_count)
+ goto unlock;
+
+ pmu->type = -1;
+ if (!name)
+ goto skip_type;
+ pmu->name = name;
+
+ if (type < 0) {
+ int err = idr_pre_get(&pmu_idr, GFP_KERNEL);
+ if (!err)
+ goto free_pdc;
+
+ err = idr_get_new_above(&pmu_idr, pmu, PERF_TYPE_MAX, &type);
+ if (err) {
+ ret = err;
+ goto free_pdc;
+ }
+ }
+ pmu->type = type;
+
+ if (pmu_bus_running) {
+ ret = pmu_dev_alloc(pmu);
+ if (ret)
+ goto free_idr;
+ }
+
+skip_type:
+ pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
+ if (pmu->pmu_cpu_context)
+ goto got_cpu_context;
+
+ pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
+ if (!pmu->pmu_cpu_context)
+ goto free_dev;
+
+ for_each_possible_cpu(cpu) {
+ struct perf_cpu_context *cpuctx;
+
+ cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
+ __perf_event_init_context(&cpuctx->ctx);
+ lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
+ cpuctx->ctx.type = cpu_context;
+ cpuctx->ctx.pmu = pmu;
+ cpuctx->jiffies_interval = 1;
+ INIT_LIST_HEAD(&cpuctx->rotation_list);
+ cpuctx->active_pmu = pmu;
+ }
+
+got_cpu_context:
+ if (!pmu->start_txn) {
+ if (pmu->pmu_enable) {
+ /*
+ * If we have pmu_enable/pmu_disable calls, install
+ * transaction stubs that use that to try and batch
+ * hardware accesses.
+ */
+ pmu->start_txn = perf_pmu_start_txn;
+ pmu->commit_txn = perf_pmu_commit_txn;
+ pmu->cancel_txn = perf_pmu_cancel_txn;
+ } else {
+ pmu->start_txn = perf_pmu_nop_void;
+ pmu->commit_txn = perf_pmu_nop_int;
+ pmu->cancel_txn = perf_pmu_nop_void;
+ }
+ }
+
+ if (!pmu->pmu_enable) {
+ pmu->pmu_enable = perf_pmu_nop_void;
+ pmu->pmu_disable = perf_pmu_nop_void;
+ }
+
+ list_add_rcu(&pmu->entry, &pmus);
+ ret = 0;
+unlock:
+ mutex_unlock(&pmus_lock);
+
+ return ret;
+
+free_dev:
+ device_del(pmu->dev);
+ put_device(pmu->dev);
+
+free_idr:
+ if (pmu->type >= PERF_TYPE_MAX)
+ idr_remove(&pmu_idr, pmu->type);
+
+free_pdc:
+ free_percpu(pmu->pmu_disable_count);
+ goto unlock;
+}
+
+void perf_pmu_unregister(struct pmu *pmu)
+{
+ mutex_lock(&pmus_lock);
+ list_del_rcu(&pmu->entry);
+ mutex_unlock(&pmus_lock);
+
+ /*
+ * We dereference the pmu list under both SRCU and regular RCU, so
+ * synchronize against both of those.
+ */
+ synchronize_srcu(&pmus_srcu);
+ synchronize_rcu();
+
+ free_percpu(pmu->pmu_disable_count);
+ if (pmu->type >= PERF_TYPE_MAX)
+ idr_remove(&pmu_idr, pmu->type);
+ device_del(pmu->dev);
+ put_device(pmu->dev);
+ free_pmu_context(pmu);
+}
+
+struct pmu *perf_init_event(struct perf_event *event)
+{
+ struct pmu *pmu = NULL;
+ int idx;
+ int ret;
+
+ idx = srcu_read_lock(&pmus_srcu);
+
+ rcu_read_lock();
+ pmu = idr_find(&pmu_idr, event->attr.type);
+ rcu_read_unlock();
+ if (pmu) {
+ ret = pmu->event_init(event);
+ if (ret)
+ pmu = ERR_PTR(ret);
+ goto unlock;
+ }
+
+ list_for_each_entry_rcu(pmu, &pmus, entry) {
+ ret = pmu->event_init(event);
+ if (!ret)
+ goto unlock;
+
+ if (ret != -ENOENT) {
+ pmu = ERR_PTR(ret);
+ goto unlock;
+ }
+ }
+ pmu = ERR_PTR(-ENOENT);
+unlock:
+ srcu_read_unlock(&pmus_srcu, idx);
+
+ return pmu;
+}
+
+/*
+ * Allocate and initialize a event structure
+ */
+static struct perf_event *
+perf_event_alloc(struct perf_event_attr *attr, int cpu,
+ struct task_struct *task,
+ struct perf_event *group_leader,
+ struct perf_event *parent_event,
+ perf_overflow_handler_t overflow_handler)
+{
+ struct pmu *pmu;
+ struct perf_event *event;
+ struct hw_perf_event *hwc;
+ long err;
+
+ if ((unsigned)cpu >= nr_cpu_ids) {
+ if (!task || cpu != -1)
+ return ERR_PTR(-EINVAL);
+ }
+
+ event = kzalloc(sizeof(*event), GFP_KERNEL);
+ if (!event)
+ return ERR_PTR(-ENOMEM);
+
+ /*
+ * Single events are their own group leaders, with an
+ * empty sibling list:
+ */
+ if (!group_leader)
+ group_leader = event;
+
+ mutex_init(&event->child_mutex);
+ INIT_LIST_HEAD(&event->child_list);
+
+ INIT_LIST_HEAD(&event->group_entry);
+ INIT_LIST_HEAD(&event->event_entry);
+ INIT_LIST_HEAD(&event->sibling_list);
+ init_waitqueue_head(&event->waitq);
+ init_irq_work(&event->pending, perf_pending_event);
+
+ mutex_init(&event->mmap_mutex);
+
+ event->cpu = cpu;
+ event->attr = *attr;
+ event->group_leader = group_leader;
+ event->pmu = NULL;
+ event->oncpu = -1;
+
+ event->parent = parent_event;
+
+ event->ns = get_pid_ns(current->nsproxy->pid_ns);
+ event->id = atomic64_inc_return(&perf_event_id);
+
+ event->state = PERF_EVENT_STATE_INACTIVE;
+
+ if (task) {
+ event->attach_state = PERF_ATTACH_TASK;
+#ifdef CONFIG_HAVE_HW_BREAKPOINT
+ /*
+ * hw_breakpoint is a bit difficult here..
+ */
+ if (attr->type == PERF_TYPE_BREAKPOINT)
+ event->hw.bp_target = task;
+#endif
+ }
+
+ if (!overflow_handler && parent_event)
+ overflow_handler = parent_event->overflow_handler;
+
+ event->overflow_handler = overflow_handler;
+
+ if (attr->disabled)
+ event->state = PERF_EVENT_STATE_OFF;
+
+ pmu = NULL;
+
+ hwc = &event->hw;
+ hwc->sample_period = attr->sample_period;
+ if (attr->freq && attr->sample_freq)
+ hwc->sample_period = 1;
+ hwc->last_period = hwc->sample_period;
+
+ local64_set(&hwc->period_left, hwc->sample_period);
+
+ /*
+ * we currently do not support PERF_FORMAT_GROUP on inherited events
+ */
+ if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
+ goto done;
+
+ pmu = perf_init_event(event);
+
+done:
+ err = 0;
+ if (!pmu)
+ err = -EINVAL;
+ else if (IS_ERR(pmu))
+ err = PTR_ERR(pmu);
+
+ if (err) {
+ if (event->ns)
+ put_pid_ns(event->ns);
+ kfree(event);
+ return ERR_PTR(err);
+ }
+
+ event->pmu = pmu;
+
+ if (!event->parent) {
+ if (event->attach_state & PERF_ATTACH_TASK)
+ jump_label_inc(&perf_sched_events);
+ if (event->attr.mmap || event->attr.mmap_data)
+ atomic_inc(&nr_mmap_events);
+ if (event->attr.comm)
+ atomic_inc(&nr_comm_events);
+ if (event->attr.task)
+ atomic_inc(&nr_task_events);
+ if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
+ err = get_callchain_buffers();
+ if (err) {
+ free_event(event);
+ return ERR_PTR(err);
+ }
+ }
+ }
+
+ return event;
+}
+
+static int perf_copy_attr(struct perf_event_attr __user *uattr,
+ struct perf_event_attr *attr)
+{
+ u32 size;
+ int ret;
+
+ if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
+ return -EFAULT;
+
+ /*
+ * zero the full structure, so that a short copy will be nice.
+ */
+ memset(attr, 0, sizeof(*attr));
+
+ ret = get_user(size, &uattr->size);
+ if (ret)
+ return ret;
+
+ if (size > PAGE_SIZE) /* silly large */
+ goto err_size;
+
+ if (!size) /* abi compat */
+ size = PERF_ATTR_SIZE_VER0;
+
+ if (size < PERF_ATTR_SIZE_VER0)
+ goto err_size;
+
+ /*
+ * If we're handed a bigger struct than we know of,
+ * ensure all the unknown bits are 0 - i.e. new
+ * user-space does not rely on any kernel feature
+ * extensions we dont know about yet.
+ */
+ if (size > sizeof(*attr)) {
+ unsigned char __user *addr;
+ unsigned char __user *end;
+ unsigned char val;
+
+ addr = (void __user *)uattr + sizeof(*attr);
+ end = (void __user *)uattr + size;
+
+ for (; addr < end; addr++) {
+ ret = get_user(val, addr);
+ if (ret)
+ return ret;
+ if (val)
+ goto err_size;
+ }
+ size = sizeof(*attr);
+ }
+
+ ret = copy_from_user(attr, uattr, size);
+ if (ret)
+ return -EFAULT;
+
+ /*
+ * If the type exists, the corresponding creation will verify
+ * the attr->config.
+ */
+ if (attr->type >= PERF_TYPE_MAX)
+ return -EINVAL;
+
+ if (attr->__reserved_1)
+ return -EINVAL;
+
+ if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
+ return -EINVAL;
+
+ if (attr->read_format & ~(PERF_FORMAT_MAX-1))
+ return -EINVAL;
+
+out:
+ return ret;
+
+err_size:
+ put_user(sizeof(*attr), &uattr->size);
+ ret = -E2BIG;
+ goto out;
+}
+
+static int
+perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
+{
+ struct perf_buffer *buffer = NULL, *old_buffer = NULL;
+ int ret = -EINVAL;
+
+ if (!output_event)
+ goto set;
+
+ /* don't allow circular references */
+ if (event == output_event)
+ goto out;
+
+ /*
+ * Don't allow cross-cpu buffers
+ */
+ if (output_event->cpu != event->cpu)
+ goto out;
+
+ /*
+ * If its not a per-cpu buffer, it must be the same task.
+ */
+ if (output_event->cpu == -1 && output_event->ctx != event->ctx)
+ goto out;
+
+set:
+ mutex_lock(&event->mmap_mutex);
+ /* Can't redirect output if we've got an active mmap() */
+ if (atomic_read(&event->mmap_count))
+ goto unlock;
+
+ if (output_event) {
+ /* get the buffer we want to redirect to */
+ buffer = perf_buffer_get(output_event);
+ if (!buffer)
+ goto unlock;
+ }
+
+ old_buffer = event->buffer;
+ rcu_assign_pointer(event->buffer, buffer);
+ ret = 0;
+unlock:
+ mutex_unlock(&event->mmap_mutex);
+
+ if (old_buffer)
+ perf_buffer_put(old_buffer);
+out:
+ return ret;
+}
+
+/**
+ * sys_perf_event_open - open a performance event, associate it to a task/cpu
+ *
+ * @attr_uptr: event_id type attributes for monitoring/sampling
+ * @pid: target pid
+ * @cpu: target cpu
+ * @group_fd: group leader event fd
+ */
+SYSCALL_DEFINE5(perf_event_open,
+ struct perf_event_attr __user *, attr_uptr,
+ pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
+{
+ struct perf_event *group_leader = NULL, *output_event = NULL;
+ struct perf_event *event, *sibling;
+ struct perf_event_attr attr;
+ struct perf_event_context *ctx;
+ struct file *event_file = NULL;
+ struct file *group_file = NULL;
+ struct task_struct *task = NULL;
+ struct pmu *pmu;
+ int event_fd;
+ int move_group = 0;
+ int fput_needed = 0;
+ int err;
+
+ /* for future expandability... */
+ if (flags & ~PERF_FLAG_ALL)
+ return -EINVAL;
+
+ err = perf_copy_attr(attr_uptr, &attr);
+ if (err)
+ return err;
+
+ if (!attr.exclude_kernel) {
+ if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
+ return -EACCES;
+ }
+
+ if (attr.freq) {
+ if (attr.sample_freq > sysctl_perf_event_sample_rate)
+ return -EINVAL;
+ }
+
+ /*
+ * In cgroup mode, the pid argument is used to pass the fd
+ * opened to the cgroup directory in cgroupfs. The cpu argument
+ * designates the cpu on which to monitor threads from that
+ * cgroup.
+ */
+ if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
+ return -EINVAL;
+
+ event_fd = get_unused_fd_flags(O_RDWR);
+ if (event_fd < 0)
+ return event_fd;
+
+ if (group_fd != -1) {
+ group_leader = perf_fget_light(group_fd, &fput_needed);
+ if (IS_ERR(group_leader)) {
+ err = PTR_ERR(group_leader);
+ goto err_fd;
+ }
+ group_file = group_leader->filp;
+ if (flags & PERF_FLAG_FD_OUTPUT)
+ output_event = group_leader;
+ if (flags & PERF_FLAG_FD_NO_GROUP)
+ group_leader = NULL;
+ }
+
+ if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
+ task = find_lively_task_by_vpid(pid);
+ if (IS_ERR(task)) {
+ err = PTR_ERR(task);
+ goto err_group_fd;
+ }
+ }
+
+ event = perf_event_alloc(&attr, cpu, task, group_leader, NULL, NULL);
+ if (IS_ERR(event)) {
+ err = PTR_ERR(event);
+ goto err_task;
+ }
+
+ if (flags & PERF_FLAG_PID_CGROUP) {
+ err = perf_cgroup_connect(pid, event, &attr, group_leader);
+ if (err)
+ goto err_alloc;
+ /*
+ * one more event:
+ * - that has cgroup constraint on event->cpu
+ * - that may need work on context switch
+ */
+ atomic_inc(&per_cpu(perf_cgroup_events, event->cpu));
+ jump_label_inc(&perf_sched_events);
+ }
+
+ /*
+ * Special case software events and allow them to be part of
+ * any hardware group.
+ */
+ pmu = event->pmu;
+
+ if (group_leader &&
+ (is_software_event(event) != is_software_event(group_leader))) {
+ if (is_software_event(event)) {
+ /*
+ * If event and group_leader are not both a software
+ * event, and event is, then group leader is not.
+ *
+ * Allow the addition of software events to !software
+ * groups, this is safe because software events never
+ * fail to schedule.
+ */
+ pmu = group_leader->pmu;
+ } else if (is_software_event(group_leader) &&
+ (group_leader->group_flags & PERF_GROUP_SOFTWARE)) {
+ /*
+ * In case the group is a pure software group, and we
+ * try to add a hardware event, move the whole group to
+ * the hardware context.
+ */
+ move_group = 1;
+ }
+ }
+
+ /*
+ * Get the target context (task or percpu):
+ */
+ ctx = find_get_context(pmu, task, cpu);
+ if (IS_ERR(ctx)) {
+ err = PTR_ERR(ctx);
+ goto err_alloc;
+ }
+
+ if (task) {
+ put_task_struct(task);
+ task = NULL;
+ }
+
+ /*
+ * Look up the group leader (we will attach this event to it):
+ */
+ if (group_leader) {
+ err = -EINVAL;
+
+ /*
+ * Do not allow a recursive hierarchy (this new sibling
+ * becoming part of another group-sibling):
+ */
+ if (group_leader->group_leader != group_leader)
+ goto err_context;
+ /*
+ * Do not allow to attach to a group in a different
+ * task or CPU context:
+ */
+ if (move_group) {
+ if (group_leader->ctx->type != ctx->type)
+ goto err_context;
+ } else {
+ if (group_leader->ctx != ctx)
+ goto err_context;
+ }
+
+ /*
+ * Only a group leader can be exclusive or pinned
+ */
+ if (attr.exclusive || attr.pinned)
+ goto err_context;
+ }
+
+ if (output_event) {
+ err = perf_event_set_output(event, output_event);
+ if (err)
+ goto err_context;
+ }
+
+ event_file = anon_inode_getfile("[perf_event]", &perf_fops, event, O_RDWR);
+ if (IS_ERR(event_file)) {
+ err = PTR_ERR(event_file);
+ goto err_context;
+ }
+
+ if (move_group) {
+ struct perf_event_context *gctx = group_leader->ctx;
+
+ mutex_lock(&gctx->mutex);
+ perf_remove_from_context(group_leader);
+ list_for_each_entry(sibling, &group_leader->sibling_list,
+ group_entry) {
+ perf_remove_from_context(sibling);
+ put_ctx(gctx);
+ }
+ mutex_unlock(&gctx->mutex);
+ put_ctx(gctx);
+ }
+
+ event->filp = event_file;
+ WARN_ON_ONCE(ctx->parent_ctx);
+ mutex_lock(&ctx->mutex);
+
+ if (move_group) {
+ perf_install_in_context(ctx, group_leader, cpu);
+ get_ctx(ctx);
+ list_for_each_entry(sibling, &group_leader->sibling_list,
+ group_entry) {
+ perf_install_in_context(ctx, sibling, cpu);
+ get_ctx(ctx);
+ }
+ }
+
+ perf_install_in_context(ctx, event, cpu);
+ ++ctx->generation;
+ perf_unpin_context(ctx);
+ mutex_unlock(&ctx->mutex);
+
+ event->owner = current;
+
+ mutex_lock(¤t->perf_event_mutex);
+ list_add_tail(&event->owner_entry, ¤t->perf_event_list);
+ mutex_unlock(¤t->perf_event_mutex);
+
+ /*
+ * Precalculate sample_data sizes
+ */
+ perf_event__header_size(event);
+ perf_event__id_header_size(event);
+
+ /*
+ * Drop the reference on the group_event after placing the
+ * new event on the sibling_list. This ensures destruction
+ * of the group leader will find the pointer to itself in
+ * perf_group_detach().
+ */
+ fput_light(group_file, fput_needed);
+ fd_install(event_fd, event_file);
+ return event_fd;
+
+err_context:
+ perf_unpin_context(ctx);
+ put_ctx(ctx);
+err_alloc:
+ free_event(event);
+err_task:
+ if (task)
+ put_task_struct(task);
+err_group_fd:
+ fput_light(group_file, fput_needed);
+err_fd:
+ put_unused_fd(event_fd);
+ return err;
+}
+
+/**
+ * perf_event_create_kernel_counter
+ *
+ * @attr: attributes of the counter to create
+ * @cpu: cpu in which the counter is bound
+ * @task: task to profile (NULL for percpu)
+ */
+struct perf_event *
+perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
+ struct task_struct *task,
+ perf_overflow_handler_t overflow_handler)
+{
+ struct perf_event_context *ctx;
+ struct perf_event *event;
+ int err;
+
+ /*
+ * Get the target context (task or percpu):
+ */
+
+ event = perf_event_alloc(attr, cpu, task, NULL, NULL, overflow_handler);
+ if (IS_ERR(event)) {
+ err = PTR_ERR(event);
+ goto err;
+ }
+
+ ctx = find_get_context(event->pmu, task, cpu);
+ if (IS_ERR(ctx)) {
+ err = PTR_ERR(ctx);
+ goto err_free;
+ }
+
+ event->filp = NULL;
+ WARN_ON_ONCE(ctx->parent_ctx);
+ mutex_lock(&ctx->mutex);
+ perf_install_in_context(ctx, event, cpu);
+ ++ctx->generation;
+ perf_unpin_context(ctx);
+ mutex_unlock(&ctx->mutex);
+
+ return event;
+
+err_free:
+ free_event(event);
+err:
+ return ERR_PTR(err);
+}
+EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
+
+static void sync_child_event(struct perf_event *child_event,
+ struct task_struct *child)
+{
+ struct perf_event *parent_event = child_event->parent;
+ u64 child_val;
+
+ if (child_event->attr.inherit_stat)
+ perf_event_read_event(child_event, child);
+
+ child_val = perf_event_count(child_event);
+
+ /*
+ * Add back the child's count to the parent's count:
+ */
+ atomic64_add(child_val, &parent_event->child_count);
+ atomic64_add(child_event->total_time_enabled,
+ &parent_event->child_total_time_enabled);
+ atomic64_add(child_event->total_time_running,
+ &parent_event->child_total_time_running);
+
+ /*
+ * Remove this event from the parent's list
+ */
+ WARN_ON_ONCE(parent_event->ctx->parent_ctx);
+ mutex_lock(&parent_event->child_mutex);
+ list_del_init(&child_event->child_list);
+ mutex_unlock(&parent_event->child_mutex);
+
+ /*
+ * Release the parent event, if this was the last
+ * reference to it.
+ */
+ fput(parent_event->filp);
+}
+
+static void
+__perf_event_exit_task(struct perf_event *child_event,
+ struct perf_event_context *child_ctx,
+ struct task_struct *child)
+{
+ if (child_event->parent) {
+ raw_spin_lock_irq(&child_ctx->lock);
+ perf_group_detach(child_event);
+ raw_spin_unlock_irq(&child_ctx->lock);
+ }
+
+ perf_remove_from_context(child_event);
+
+ /*
+ * It can happen that the parent exits first, and has events
+ * that are still around due to the child reference. These
+ * events need to be zapped.
+ */
+ if (child_event->parent) {
+ sync_child_event(child_event, child);
+ free_event(child_event);
+ }
+}
+
+static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
+{
+ struct perf_event *child_event, *tmp;
+ struct perf_event_context *child_ctx;
+ unsigned long flags;
+
+ if (likely(!child->perf_event_ctxp[ctxn])) {
+ perf_event_task(child, NULL, 0);
+ return;
+ }
+
+ local_irq_save(flags);
+ /*
+ * We can't reschedule here because interrupts are disabled,
+ * and either child is current or it is a task that can't be
+ * scheduled, so we are now safe from rescheduling changing
+ * our context.
+ */
+ child_ctx = rcu_dereference_raw(child->perf_event_ctxp[ctxn]);
+ task_ctx_sched_out(child_ctx, EVENT_ALL);
+
+ /*
+ * Take the context lock here so that if find_get_context is
+ * reading child->perf_event_ctxp, we wait until it has
+ * incremented the context's refcount before we do put_ctx below.
+ */
+ raw_spin_lock(&child_ctx->lock);
+ child->perf_event_ctxp[ctxn] = NULL;
+ /*
+ * If this context is a clone; unclone it so it can't get
+ * swapped to another process while we're removing all
+ * the events from it.
+ */
+ unclone_ctx(child_ctx);
+ update_context_time(child_ctx);
+ raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
+
+ /*
+ * Report the task dead after unscheduling the events so that we
+ * won't get any samples after PERF_RECORD_EXIT. We can however still
+ * get a few PERF_RECORD_READ events.
+ */
+ perf_event_task(child, child_ctx, 0);
+
+ /*
+ * We can recurse on the same lock type through:
+ *
+ * __perf_event_exit_task()
+ * sync_child_event()
+ * fput(parent_event->filp)
+ * perf_release()
+ * mutex_lock(&ctx->mutex)
+ *
+ * But since its the parent context it won't be the same instance.
+ */
+ mutex_lock(&child_ctx->mutex);
+
+again:
+ list_for_each_entry_safe(child_event, tmp, &child_ctx->pinned_groups,
+ group_entry)
+ __perf_event_exit_task(child_event, child_ctx, child);
+
+ list_for_each_entry_safe(child_event, tmp, &child_ctx->flexible_groups,
+ group_entry)
+ __perf_event_exit_task(child_event, child_ctx, child);
+
+ /*
+ * If the last event was a group event, it will have appended all
+ * its siblings to the list, but we obtained 'tmp' before that which
+ * will still point to the list head terminating the iteration.
+ */
+ if (!list_empty(&child_ctx->pinned_groups) ||
+ !list_empty(&child_ctx->flexible_groups))
+ goto again;
+
+ mutex_unlock(&child_ctx->mutex);
+
+ put_ctx(child_ctx);
+}
+
+/*
+ * When a child task exits, feed back event values to parent events.
+ */
+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);
+}
+
+static void perf_free_event(struct perf_event *event,
+ struct perf_event_context *ctx)
+{
+ struct perf_event *parent = event->parent;
+
+ if (WARN_ON_ONCE(!parent))
+ return;
+
+ mutex_lock(&parent->child_mutex);
+ list_del_init(&event->child_list);
+ mutex_unlock(&parent->child_mutex);
+
+ fput(parent->filp);
+
+ perf_group_detach(event);
+ list_del_event(event, ctx);
+ free_event(event);
+}
+
+/*
+ * free an unexposed, unused context as created by inheritance by
+ * perf_event_init_task below, used by fork() in case of fail.
+ */
+void perf_event_free_task(struct task_struct *task)
+{
+ struct perf_event_context *ctx;
+ struct perf_event *event, *tmp;
+ int ctxn;
+
+ for_each_task_context_nr(ctxn) {
+ ctx = task->perf_event_ctxp[ctxn];
+ if (!ctx)
+ continue;
+
+ mutex_lock(&ctx->mutex);
+again:
+ list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
+ group_entry)
+ perf_free_event(event, ctx);
+
+ list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
+ group_entry)
+ perf_free_event(event, ctx);
+
+ if (!list_empty(&ctx->pinned_groups) ||
+ !list_empty(&ctx->flexible_groups))
+ goto again;
+
+ mutex_unlock(&ctx->mutex);
+
+ put_ctx(ctx);
+ }
+}
+
+void perf_event_delayed_put(struct task_struct *task)
+{
+ int ctxn;
+
+ for_each_task_context_nr(ctxn)
+ WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
+}
+
+/*
+ * inherit a event from parent task to child task:
+ */
+static struct perf_event *
+inherit_event(struct perf_event *parent_event,
+ struct task_struct *parent,
+ struct perf_event_context *parent_ctx,
+ struct task_struct *child,
+ struct perf_event *group_leader,
+ struct perf_event_context *child_ctx)
+{
+ struct perf_event *child_event;
+ unsigned long flags;
+
+ /*
+ * Instead of creating recursive hierarchies of events,
+ * we link inherited events back to the original parent,
+ * which has a filp for sure, which we use as the reference
+ * count:
+ */
+ if (parent_event->parent)
+ parent_event = parent_event->parent;
+
+ child_event = perf_event_alloc(&parent_event->attr,
+ parent_event->cpu,
+ child,
+ group_leader, parent_event,
+ NULL);
+ if (IS_ERR(child_event))
+ return child_event;
+ get_ctx(child_ctx);
+
+ /*
+ * Make the child state follow the state of the parent event,
+ * not its attr.disabled bit. We hold the parent's mutex,
+ * so we won't race with perf_event_{en, dis}able_family.
+ */
+ if (parent_event->state >= PERF_EVENT_STATE_INACTIVE)
+ child_event->state = PERF_EVENT_STATE_INACTIVE;
+ else
+ child_event->state = PERF_EVENT_STATE_OFF;
+
+ if (parent_event->attr.freq) {
+ u64 sample_period = parent_event->hw.sample_period;
+ struct hw_perf_event *hwc = &child_event->hw;
+
+ hwc->sample_period = sample_period;
+ hwc->last_period = sample_period;
+
+ local64_set(&hwc->period_left, sample_period);
+ }
+
+ child_event->ctx = child_ctx;
+ child_event->overflow_handler = parent_event->overflow_handler;
+
+ /*
+ * Precalculate sample_data sizes
+ */
+ perf_event__header_size(child_event);
+ perf_event__id_header_size(child_event);
+
+ /*
+ * Link it up in the child's context:
+ */
+ raw_spin_lock_irqsave(&child_ctx->lock, flags);
+ add_event_to_ctx(child_event, child_ctx);
+ raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
+
+ /*
+ * Get a reference to the parent filp - we will fput it
+ * when the child event exits. This is safe to do because
+ * we are in the parent and we know that the filp still
+ * exists and has a nonzero count:
+ */
+ atomic_long_inc(&parent_event->filp->f_count);
+
+ /*
+ * Link this into the parent event's child list
+ */
+ WARN_ON_ONCE(parent_event->ctx->parent_ctx);
+ mutex_lock(&parent_event->child_mutex);
+ list_add_tail(&child_event->child_list, &parent_event->child_list);
+ mutex_unlock(&parent_event->child_mutex);
+
+ return child_event;
+}
+
+static int inherit_group(struct perf_event *parent_event,
+ struct task_struct *parent,
+ struct perf_event_context *parent_ctx,
+ struct task_struct *child,
+ struct perf_event_context *child_ctx)
+{
+ struct perf_event *leader;
+ struct perf_event *sub;
+ struct perf_event *child_ctr;
+
+ leader = inherit_event(parent_event, parent, parent_ctx,
+ child, NULL, child_ctx);
+ if (IS_ERR(leader))
+ return PTR_ERR(leader);
+ list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
+ child_ctr = inherit_event(sub, parent, parent_ctx,
+ child, leader, child_ctx);
+ if (IS_ERR(child_ctr))
+ return PTR_ERR(child_ctr);
+ }
+ return 0;
+}
+
+static int
+inherit_task_group(struct perf_event *event, struct task_struct *parent,
+ struct perf_event_context *parent_ctx,
+ struct task_struct *child, int ctxn,
+ int *inherited_all)
+{
+ int ret;
+ struct perf_event_context *child_ctx;
+
+ if (!event->attr.inherit) {
+ *inherited_all = 0;
+ return 0;
+ }
+
+ child_ctx = child->perf_event_ctxp[ctxn];
+ if (!child_ctx) {
+ /*
+ * This is executed from the parent task context, so
+ * inherit events that have been marked for cloning.
+ * First allocate and initialize a context for the
+ * child.
+ */
+
+ child_ctx = alloc_perf_context(event->pmu, child);
+ if (!child_ctx)
+ return -ENOMEM;
+
+ child->perf_event_ctxp[ctxn] = child_ctx;
+ }
+
+ ret = inherit_group(event, parent, parent_ctx,
+ child, child_ctx);
+
+ if (ret)
+ *inherited_all = 0;
+
+ return ret;
+}
+
+/*
+ * Initialize the perf_event context in task_struct
+ */
+int perf_event_init_context(struct task_struct *child, int ctxn)
+{
+ struct perf_event_context *child_ctx, *parent_ctx;
+ struct perf_event_context *cloned_ctx;
+ struct perf_event *event;
+ struct task_struct *parent = current;
+ int inherited_all = 1;
+ unsigned long flags;
+ int ret = 0;
+
+ if (likely(!parent->perf_event_ctxp[ctxn]))
+ return 0;
+
+ /*
+ * If the parent's context is a clone, pin it so it won't get
+ * swapped under us.
+ */
+ parent_ctx = perf_pin_task_context(parent, ctxn);
+
+ /*
+ * No need to check if parent_ctx != NULL here; since we saw
+ * it non-NULL earlier, the only reason for it to become NULL
+ * is if we exit, and since we're currently in the middle of
+ * a fork we can't be exiting at the same time.
+ */
+
+ /*
+ * Lock the parent list. No need to lock the child - not PID
+ * hashed yet and not running, so nobody can access it.
+ */
+ mutex_lock(&parent_ctx->mutex);
+
+ /*
+ * We dont have to disable NMIs - we are only looking at
+ * the list, not manipulating it:
+ */
+ list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
+ ret = inherit_task_group(event, parent, parent_ctx,
+ child, ctxn, &inherited_all);
+ if (ret)
+ 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);
+ if (ret)
+ break;
+ }
+
+ raw_spin_lock_irqsave(&parent_ctx->lock, flags);
+ parent_ctx->rotate_disable = 0;
+
+ child_ctx = child->perf_event_ctxp[ctxn];
+
+ if (child_ctx && inherited_all) {
+ /*
+ * Mark the child context as a clone of the parent
+ * context, or of whatever the parent is a clone of.
+ *
+ * Note that if the parent is a clone, the holding of
+ * parent_ctx->lock avoids it from being uncloned.
+ */
+ cloned_ctx = parent_ctx->parent_ctx;
+ if (cloned_ctx) {
+ child_ctx->parent_ctx = cloned_ctx;
+ child_ctx->parent_gen = parent_ctx->parent_gen;
+ } else {
+ child_ctx->parent_ctx = parent_ctx;
+ child_ctx->parent_gen = parent_ctx->generation;
+ }
+ get_ctx(child_ctx->parent_ctx);
+ }
+
+ raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
+ mutex_unlock(&parent_ctx->mutex);
+
+ perf_unpin_context(parent_ctx);
+ put_ctx(parent_ctx);
+
+ return ret;
+}
+
+/*
+ * Initialize the perf_event context in task_struct
+ */
+int perf_event_init_task(struct task_struct *child)
+{
+ int ctxn, ret;
+
+ memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
+ mutex_init(&child->perf_event_mutex);
+ INIT_LIST_HEAD(&child->perf_event_list);
+
+ for_each_task_context_nr(ctxn) {
+ ret = perf_event_init_context(child, ctxn);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
+static void __init perf_event_init_all_cpus(void)
+{
+ struct swevent_htable *swhash;
+ int cpu;
+
+ for_each_possible_cpu(cpu) {
+ swhash = &per_cpu(swevent_htable, cpu);
+ mutex_init(&swhash->hlist_mutex);
+ INIT_LIST_HEAD(&per_cpu(rotation_list, cpu));
+ }
+}
+
+static void __cpuinit perf_event_init_cpu(int cpu)
+{
+ struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
+
+ mutex_lock(&swhash->hlist_mutex);
+ if (swhash->hlist_refcount > 0) {
+ struct swevent_hlist *hlist;
+
+ hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
+ WARN_ON(!hlist);
+ rcu_assign_pointer(swhash->swevent_hlist, hlist);
+ }
+ mutex_unlock(&swhash->hlist_mutex);
+}
+
+#if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC
+static void perf_pmu_rotate_stop(struct pmu *pmu)
+{
+ struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
+
+ WARN_ON(!irqs_disabled());
+
+ list_del_init(&cpuctx->rotation_list);
+}
+
+static void __perf_event_exit_context(void *__info)
+{
+ struct perf_event_context *ctx = __info;
+ struct perf_event *event, *tmp;
+
+ perf_pmu_rotate_stop(ctx->pmu);
+
+ list_for_each_entry_safe(event, tmp, &ctx->pinned_groups, group_entry)
+ __perf_remove_from_context(event);
+ list_for_each_entry_safe(event, tmp, &ctx->flexible_groups, group_entry)
+ __perf_remove_from_context(event);
+}
+
+static void perf_event_exit_cpu_context(int cpu)
+{
+ struct perf_event_context *ctx;
+ struct pmu *pmu;
+ int idx;
+
+ idx = srcu_read_lock(&pmus_srcu);
+ list_for_each_entry_rcu(pmu, &pmus, entry) {
+ ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
+
+ mutex_lock(&ctx->mutex);
+ smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
+ mutex_unlock(&ctx->mutex);
+ }
+ srcu_read_unlock(&pmus_srcu, idx);
+}
+
+static void perf_event_exit_cpu(int cpu)
+{
+ struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
+
+ mutex_lock(&swhash->hlist_mutex);
+ swevent_hlist_release(swhash);
+ mutex_unlock(&swhash->hlist_mutex);
+
+ perf_event_exit_cpu_context(cpu);
+}
+#else
+static inline void perf_event_exit_cpu(int cpu) { }
+#endif
+
+static int
+perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
+{
+ int cpu;
+
+ for_each_online_cpu(cpu)
+ perf_event_exit_cpu(cpu);
+
+ return NOTIFY_OK;
+}
+
+/*
+ * Run the perf reboot notifier at the very last possible moment so that
+ * the generic watchdog code runs as long as possible.
+ */
+static struct notifier_block perf_reboot_notifier = {
+ .notifier_call = perf_reboot,
+ .priority = INT_MIN,
+};
+
+static int __cpuinit
+perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
+{
+ unsigned int cpu = (long)hcpu;
+
+ switch (action & ~CPU_TASKS_FROZEN) {
+
+ case CPU_UP_PREPARE:
+ case CPU_DOWN_FAILED:
+ perf_event_init_cpu(cpu);
+ break;
+
+ case CPU_UP_CANCELED:
+ case CPU_DOWN_PREPARE:
+ perf_event_exit_cpu(cpu);
+ break;
+
+ default:
+ break;
+ }
+
+ return NOTIFY_OK;
+}
+
+void __init perf_event_init(void)
+{
+ int ret;
+
+ idr_init(&pmu_idr);
+
+ perf_event_init_all_cpus();
+ init_srcu_struct(&pmus_srcu);
+ perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
+ perf_pmu_register(&perf_cpu_clock, NULL, -1);
+ perf_pmu_register(&perf_task_clock, NULL, -1);
+ perf_tp_register();
+ perf_cpu_notifier(perf_cpu_notify);
+ register_reboot_notifier(&perf_reboot_notifier);
+
+ ret = init_hw_breakpoint();
+ WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
+}
+
+static int __init perf_event_sysfs_init(void)
+{
+ struct pmu *pmu;
+ int ret;
+
+ mutex_lock(&pmus_lock);
+
+ ret = bus_register(&pmu_bus);
+ if (ret)
+ goto unlock;
+
+ list_for_each_entry(pmu, &pmus, entry) {
+ if (!pmu->name || pmu->type < 0)
+ continue;
+
+ ret = pmu_dev_alloc(pmu);
+ WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
+ }
+ pmu_bus_running = 1;
+ ret = 0;
+
+unlock:
+ mutex_unlock(&pmus_lock);
+
+ return ret;
+}
+device_initcall(perf_event_sysfs_init);
+
+#ifdef CONFIG_CGROUP_PERF
+static struct cgroup_subsys_state *perf_cgroup_create(
+ struct cgroup_subsys *ss, struct cgroup *cont)
+{
+ struct perf_cgroup *jc;
+
+ jc = kzalloc(sizeof(*jc), GFP_KERNEL);
+ if (!jc)
+ return ERR_PTR(-ENOMEM);
+
+ jc->info = alloc_percpu(struct perf_cgroup_info);
+ if (!jc->info) {
+ kfree(jc);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ return &jc->css;
+}
+
+static void perf_cgroup_destroy(struct cgroup_subsys *ss,
+ struct cgroup *cont)
+{
+ struct perf_cgroup *jc;
+ jc = container_of(cgroup_subsys_state(cont, perf_subsys_id),
+ struct perf_cgroup, css);
+ free_percpu(jc->info);
+ kfree(jc);
+}
+
+static int __perf_cgroup_move(void *info)
+{
+ struct task_struct *task = info;
+ perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
+ return 0;
+}
+
+static void perf_cgroup_move(struct task_struct *task)
+{
+ task_function_call(task, __perf_cgroup_move, task);
+}
+
+static void perf_cgroup_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
+ struct cgroup *old_cgrp, struct task_struct *task,
+ bool threadgroup)
+{
+ perf_cgroup_move(task);
+ if (threadgroup) {
+ struct task_struct *c;
+ rcu_read_lock();
+ list_for_each_entry_rcu(c, &task->thread_group, thread_group) {
+ perf_cgroup_move(c);
+ }
+ rcu_read_unlock();
+ }
+}
+
+static void perf_cgroup_exit(struct cgroup_subsys *ss, struct cgroup *cgrp,
+ struct cgroup *old_cgrp, struct task_struct *task)
+{
+ /*
+ * cgroup_exit() is called in the copy_process() failure path.
+ * Ignore this case since the task hasn't ran yet, this avoids
+ * trying to poke a half freed task state from generic code.
+ */
+ if (!(task->flags & PF_EXITING))
+ return;
+
+ perf_cgroup_move(task);
+}
+
+struct cgroup_subsys perf_subsys = {
+ .name = "perf_event",
+ .subsys_id = perf_subsys_id,
+ .create = perf_cgroup_create,
+ .destroy = perf_cgroup_destroy,
+ .exit = perf_cgroup_exit,
+ .attach = perf_cgroup_attach,
+};
+#endif /* CONFIG_CGROUP_PERF */
projects / linux-flexiantxendom0-3.2.10.git / commitdiff