diff options
Diffstat (limited to 'kernel/perf_event.c')
| -rw-r--r-- | kernel/perf_event.c | 7455 |
1 files changed, 0 insertions, 7455 deletions
diff --git a/kernel/perf_event.c b/kernel/perf_event.c deleted file mode 100644 index 440bc48..0000000 --- a/kernel/perf_event.c +++ /dev/null @@ -1,7455 +0,0 @@ -/* - * Performance events core code: - * - * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de> - * Copyright (C) 2008-2009 Red Hat, Inc., Ingo Molnar - * Copyright (C) 2008-2009 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); - } -} - -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); -} - -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 */ |
