diff options
Diffstat (limited to 'kernel/events/core.c')
| -rw-r--r-- | kernel/events/core.c | 13761 |
1 files changed, 13761 insertions, 0 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c new file mode 100644 index 000000000..8c7d2f4f5 --- /dev/null +++ b/kernel/events/core.c @@ -0,0 +1,13761 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Performance events core code: + * + * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de> + * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar + * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra + * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com> + */ + +#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/tick.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/export.h> +#include <linux/vmalloc.h> +#include <linux/hardirq.h> +#include <linux/hugetlb.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/cgroup.h> +#include <linux/perf_event.h> +#include <linux/trace_events.h> +#include <linux/hw_breakpoint.h> +#include <linux/mm_types.h> +#include <linux/module.h> +#include <linux/mman.h> +#include <linux/compat.h> +#include <linux/bpf.h> +#include <linux/filter.h> +#include <linux/namei.h> +#include <linux/parser.h> +#include <linux/sched/clock.h> +#include <linux/sched/mm.h> +#include <linux/proc_ns.h> +#include <linux/mount.h> +#include <linux/min_heap.h> +#include <linux/highmem.h> +#include <linux/pgtable.h> +#include <linux/buildid.h> +#include <linux/task_work.h> + +#include "internal.h" + +#include <asm/irq_regs.h> + +typedef int (*remote_function_f)(void *); + +struct remote_function_call { + struct task_struct *p; + remote_function_f func; + void *info; + int ret; +}; + +static void remote_function(void *data) +{ + struct remote_function_call *tfc = data; + struct task_struct *p = tfc->p; + + if (p) { + /* -EAGAIN */ + if (task_cpu(p) != smp_processor_id()) + return; + + /* + * Now that we're on right CPU with IRQs disabled, we can test + * if we hit the right task without races. + */ + + tfc->ret = -ESRCH; /* No such (running) process */ + if (p != current) + 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. This will + * retry due to any failures in smp_call_function_single(), such as if the + * task_cpu() goes offline concurrently. + * + * returns @func return value or -ESRCH or -ENXIO when the process isn't running + */ +static int +task_function_call(struct task_struct *p, remote_function_f func, void *info) +{ + struct remote_function_call data = { + .p = p, + .func = func, + .info = info, + .ret = -EAGAIN, + }; + int ret; + + for (;;) { + ret = smp_call_function_single(task_cpu(p), remote_function, + &data, 1); + if (!ret) + ret = data.ret; + + if (ret != -EAGAIN) + break; + + cond_resched(); + } + + return ret; +} + +/** + * cpu_function_call - call a function on the cpu + * @cpu: target cpu to queue this function + * @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, remote_function_f func, 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; +} + +static inline struct perf_cpu_context * +__get_cpu_context(struct perf_event_context *ctx) +{ + return this_cpu_ptr(ctx->pmu->pmu_cpu_context); +} + +static void perf_ctx_lock(struct perf_cpu_context *cpuctx, + struct perf_event_context *ctx) +{ + raw_spin_lock(&cpuctx->ctx.lock); + if (ctx) + raw_spin_lock(&ctx->lock); +} + +static void perf_ctx_unlock(struct perf_cpu_context *cpuctx, + struct perf_event_context *ctx) +{ + if (ctx) + raw_spin_unlock(&ctx->lock); + raw_spin_unlock(&cpuctx->ctx.lock); +} + +#define TASK_TOMBSTONE ((void *)-1L) + +static bool is_kernel_event(struct perf_event *event) +{ + return READ_ONCE(event->owner) == TASK_TOMBSTONE; +} + +/* + * On task ctx scheduling... + * + * When !ctx->nr_events a task context will not be scheduled. This means + * we can disable the scheduler hooks (for performance) without leaving + * pending task ctx state. + * + * This however results in two special cases: + * + * - removing the last event from a task ctx; this is relatively straight + * forward and is done in __perf_remove_from_context. + * + * - adding the first event to a task ctx; this is tricky because we cannot + * rely on ctx->is_active and therefore cannot use event_function_call(). + * See perf_install_in_context(). + * + * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set. + */ + +typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *, + struct perf_event_context *, void *); + +struct event_function_struct { + struct perf_event *event; + event_f func; + void *data; +}; + +static int event_function(void *info) +{ + struct event_function_struct *efs = info; + struct perf_event *event = efs->event; + struct perf_event_context *ctx = event->ctx; + struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); + struct perf_event_context *task_ctx = cpuctx->task_ctx; + int ret = 0; + + lockdep_assert_irqs_disabled(); + + perf_ctx_lock(cpuctx, task_ctx); + /* + * Since we do the IPI call without holding ctx->lock things can have + * changed, double check we hit the task we set out to hit. + */ + if (ctx->task) { + if (ctx->task != current) { + ret = -ESRCH; + goto unlock; + } + + /* + * We only use event_function_call() on established contexts, + * and event_function() is only ever called when active (or + * rather, we'll have bailed in task_function_call() or the + * above ctx->task != current test), therefore we must have + * ctx->is_active here. + */ + WARN_ON_ONCE(!ctx->is_active); + /* + * And since we have ctx->is_active, cpuctx->task_ctx must + * match. + */ + WARN_ON_ONCE(task_ctx != ctx); + } else { + WARN_ON_ONCE(&cpuctx->ctx != ctx); + } + + efs->func(event, cpuctx, ctx, efs->data); +unlock: + perf_ctx_unlock(cpuctx, task_ctx); + + return ret; +} + +static void event_function_call(struct perf_event *event, event_f func, void *data) +{ + struct perf_event_context *ctx = event->ctx; + struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */ + struct event_function_struct efs = { + .event = event, + .func = func, + .data = data, + }; + + if (!event->parent) { + /* + * If this is a !child event, we must hold ctx::mutex to + * stabilize the event->ctx relation. See + * perf_event_ctx_lock(). + */ + lockdep_assert_held(&ctx->mutex); + } + + if (!task) { + cpu_function_call(event->cpu, event_function, &efs); + return; + } + + if (task == TASK_TOMBSTONE) + return; + +again: + if (!task_function_call(task, event_function, &efs)) + return; + + raw_spin_lock_irq(&ctx->lock); + /* + * Reload the task pointer, it might have been changed by + * a concurrent perf_event_context_sched_out(). + */ + task = ctx->task; + if (task == TASK_TOMBSTONE) { + raw_spin_unlock_irq(&ctx->lock); + return; + } + if (ctx->is_active) { + raw_spin_unlock_irq(&ctx->lock); + goto again; + } + func(event, NULL, ctx, data); + raw_spin_unlock_irq(&ctx->lock); +} + +/* + * Similar to event_function_call() + event_function(), but hard assumes IRQs + * are already disabled and we're on the right CPU. + */ +static void event_function_local(struct perf_event *event, event_f func, void *data) +{ + struct perf_event_context *ctx = event->ctx; + struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); + struct task_struct *task = READ_ONCE(ctx->task); + struct perf_event_context *task_ctx = NULL; + + lockdep_assert_irqs_disabled(); + + if (task) { + if (task == TASK_TOMBSTONE) + return; + + task_ctx = ctx; + } + + perf_ctx_lock(cpuctx, task_ctx); + + task = ctx->task; + if (task == TASK_TOMBSTONE) + goto unlock; + + if (task) { + /* + * We must be either inactive or active and the right task, + * otherwise we're screwed, since we cannot IPI to somewhere + * else. + */ + if (ctx->is_active) { + if (WARN_ON_ONCE(task != current)) + goto unlock; + + if (WARN_ON_ONCE(cpuctx->task_ctx != ctx)) + goto unlock; + } + } else { + WARN_ON_ONCE(&cpuctx->ctx != ctx); + } + + func(event, cpuctx, ctx, data); +unlock: + perf_ctx_unlock(cpuctx, task_ctx); +} + +#define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\ + PERF_FLAG_FD_OUTPUT |\ + PERF_FLAG_PID_CGROUP |\ + PERF_FLAG_FD_CLOEXEC) + +/* + * branch priv levels that need permission checks + */ +#define PERF_SAMPLE_BRANCH_PERM_PLM \ + (PERF_SAMPLE_BRANCH_KERNEL |\ + PERF_SAMPLE_BRANCH_HV) + +enum event_type_t { + EVENT_FLEXIBLE = 0x1, + EVENT_PINNED = 0x2, + EVENT_TIME = 0x4, + /* see ctx_resched() for details */ + EVENT_CPU = 0x8, + EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED, +}; + +/* + * perf_sched_events : >0 events exist + * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu + */ + +static void perf_sched_delayed(struct work_struct *work); +DEFINE_STATIC_KEY_FALSE(perf_sched_events); +static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed); +static DEFINE_MUTEX(perf_sched_mutex); +static atomic_t perf_sched_count; + +static DEFINE_PER_CPU(atomic_t, perf_cgroup_events); +static DEFINE_PER_CPU(int, perf_sched_cb_usages); +static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events); + +static atomic_t nr_mmap_events __read_mostly; +static atomic_t nr_comm_events __read_mostly; +static atomic_t nr_namespaces_events __read_mostly; +static atomic_t nr_task_events __read_mostly; +static atomic_t nr_freq_events __read_mostly; +static atomic_t nr_switch_events __read_mostly; +static atomic_t nr_ksymbol_events __read_mostly; +static atomic_t nr_bpf_events __read_mostly; +static atomic_t nr_cgroup_events __read_mostly; +static atomic_t nr_text_poke_events __read_mostly; +static atomic_t nr_build_id_events __read_mostly; + +static LIST_HEAD(pmus); +static DEFINE_MUTEX(pmus_lock); +static struct srcu_struct pmus_srcu; +static cpumask_var_t perf_online_mask; +static struct kmem_cache *perf_event_cache; + +/* + * 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 = 2; + +/* 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 +#define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE) +#define DEFAULT_CPU_TIME_MAX_PERCENT 25 + +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); +static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS; + +static int perf_sample_allowed_ns __read_mostly = + DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100; + +static void update_perf_cpu_limits(void) +{ + u64 tmp = perf_sample_period_ns; + + tmp *= sysctl_perf_cpu_time_max_percent; + tmp = div_u64(tmp, 100); + if (!tmp) + tmp = 1; + + WRITE_ONCE(perf_sample_allowed_ns, tmp); +} + +static bool perf_rotate_context(struct perf_cpu_context *cpuctx); + +int perf_proc_update_handler(struct ctl_table *table, int write, + void *buffer, size_t *lenp, loff_t *ppos) +{ + int ret; + int perf_cpu = sysctl_perf_cpu_time_max_percent; + /* + * If throttling is disabled don't allow the write: + */ + if (write && (perf_cpu == 100 || perf_cpu == 0)) + return -EINVAL; + + ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); + if (ret || !write) + return ret; + + max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ); + perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate; + update_perf_cpu_limits(); + + return 0; +} + +int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT; + +int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write, + void *buffer, size_t *lenp, loff_t *ppos) +{ + int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); + + if (ret || !write) + return ret; + + if (sysctl_perf_cpu_time_max_percent == 100 || + sysctl_perf_cpu_time_max_percent == 0) { + printk(KERN_WARNING + "perf: Dynamic interrupt throttling disabled, can hang your system!\n"); + WRITE_ONCE(perf_sample_allowed_ns, 0); + } else { + update_perf_cpu_limits(); + } + + return 0; +} + +/* + * perf samples are done in some very critical code paths (NMIs). + * If they take too much CPU time, the system can lock up and not + * get any real work done. This will drop the sample rate when + * we detect that events are taking too long. + */ +#define NR_ACCUMULATED_SAMPLES 128 +static DEFINE_PER_CPU(u64, running_sample_length); + +static u64 __report_avg; +static u64 __report_allowed; + +static void perf_duration_warn(struct irq_work *w) +{ + printk_ratelimited(KERN_INFO + "perf: interrupt took too long (%lld > %lld), lowering " + "kernel.perf_event_max_sample_rate to %d\n", + __report_avg, __report_allowed, + sysctl_perf_event_sample_rate); +} + +static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn); + +void perf_sample_event_took(u64 sample_len_ns) +{ + u64 max_len = READ_ONCE(perf_sample_allowed_ns); + u64 running_len; + u64 avg_len; + u32 max; + + if (max_len == 0) + return; + + /* Decay the counter by 1 average sample. */ + running_len = __this_cpu_read(running_sample_length); + running_len -= running_len/NR_ACCUMULATED_SAMPLES; + running_len += sample_len_ns; + __this_cpu_write(running_sample_length, running_len); + + /* + * Note: this will be biased artifically low until we have + * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us + * from having to maintain a count. + */ + avg_len = running_len/NR_ACCUMULATED_SAMPLES; + if (avg_len <= max_len) + return; + + __report_avg = avg_len; + __report_allowed = max_len; + + /* + * Compute a throttle threshold 25% below the current duration. + */ + avg_len += avg_len / 4; + max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent; + if (avg_len < max) + max /= (u32)avg_len; + else + max = 1; + + WRITE_ONCE(perf_sample_allowed_ns, avg_len); + WRITE_ONCE(max_samples_per_tick, max); + + sysctl_perf_event_sample_rate = max * HZ; + perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate; + + if (!irq_work_queue(&perf_duration_work)) { + early_printk("perf: interrupt took too long (%lld > %lld), lowering " + "kernel.perf_event_max_sample_rate to %d\n", + __report_avg, __report_allowed, + sysctl_perf_event_sample_rate); + } +} + +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); + +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) { } + +static inline u64 perf_clock(void) +{ + return local_clock(); +} + +static inline u64 perf_event_clock(struct perf_event *event) +{ + return event->clock(); +} + +/* + * State based event timekeeping... + * + * The basic idea is to use event->state to determine which (if any) time + * fields to increment with the current delta. This means we only need to + * update timestamps when we change state or when they are explicitly requested + * (read). + * + * Event groups make things a little more complicated, but not terribly so. The + * rules for a group are that if the group leader is OFF the entire group is + * OFF, irrespecive of what the group member states are. This results in + * __perf_effective_state(). + * + * A futher ramification is that when a group leader flips between OFF and + * !OFF, we need to update all group member times. + * + * + * NOTE: perf_event_time() is based on the (cgroup) context time, and thus we + * need to make sure the relevant context time is updated before we try and + * update our timestamps. + */ + +static __always_inline enum perf_event_state +__perf_effective_state(struct perf_event *event) +{ + struct perf_event *leader = event->group_leader; + + if (leader->state <= PERF_EVENT_STATE_OFF) + return leader->state; + + return event->state; +} + +static __always_inline void +__perf_update_times(struct perf_event *event, u64 now, u64 *enabled, u64 *running) +{ + enum perf_event_state state = __perf_effective_state(event); + u64 delta = now - event->tstamp; + + *enabled = event->total_time_enabled; + if (state >= PERF_EVENT_STATE_INACTIVE) + *enabled += delta; + + *running = event->total_time_running; + if (state >= PERF_EVENT_STATE_ACTIVE) + *running += delta; +} + +static void perf_event_update_time(struct perf_event *event) +{ + u64 now = perf_event_time(event); + + __perf_update_times(event, now, &event->total_time_enabled, + &event->total_time_running); + event->tstamp = now; +} + +static void perf_event_update_sibling_time(struct perf_event *leader) +{ + struct perf_event *sibling; + + for_each_sibling_event(sibling, leader) + perf_event_update_time(sibling); +} + +static void +perf_event_set_state(struct perf_event *event, enum perf_event_state state) +{ + if (event->state == state) + return; + + perf_event_update_time(event); + /* + * If a group leader gets enabled/disabled all its siblings + * are affected too. + */ + if ((event->state < 0) ^ (state < 0)) + perf_event_update_sibling_time(event); + + WRITE_ONCE(event->state, state); +} + +/* + * UP store-release, load-acquire + */ + +#define __store_release(ptr, val) \ +do { \ + barrier(); \ + WRITE_ONCE(*(ptr), (val)); \ +} while (0) + +#define __load_acquire(ptr) \ +({ \ + __unqual_scalar_typeof(*(ptr)) ___p = READ_ONCE(*(ptr)); \ + barrier(); \ + ___p; \ +}) + +#ifdef CONFIG_CGROUP_PERF + +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); + + /* @event doesn't care about cgroup */ + if (!event->cgrp) + return true; + + /* wants specific cgroup scope but @cpuctx isn't associated with any */ + if (!cpuctx->cgrp) + return false; + + /* + * Cgroup scoping is recursive. An event enabled for a cgroup is + * also enabled for all its descendant cgroups. If @cpuctx's + * cgroup is a descendant of @event's (the test covers identity + * case), it's a match. + */ + return cgroup_is_descendant(cpuctx->cgrp->css.cgroup, + event->cgrp->css.cgroup); +} + +static inline void perf_detach_cgroup(struct perf_event *event) +{ + css_put(&event->cgrp->css); + 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 u64 perf_cgroup_event_time_now(struct perf_event *event, u64 now) +{ + struct perf_cgroup_info *t; + + t = per_cpu_ptr(event->cgrp->info, event->cpu); + if (!__load_acquire(&t->active)) + return t->time; + now += READ_ONCE(t->timeoffset); + return now; +} + +static inline void __update_cgrp_time(struct perf_cgroup_info *info, u64 now, bool adv) +{ + if (adv) + info->time += now - info->timestamp; + info->timestamp = now; + /* + * see update_context_time() + */ + WRITE_ONCE(info->timeoffset, info->time - info->timestamp); +} + +static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx, bool final) +{ + struct perf_cgroup *cgrp = cpuctx->cgrp; + struct cgroup_subsys_state *css; + struct perf_cgroup_info *info; + + if (cgrp) { + u64 now = perf_clock(); + + for (css = &cgrp->css; css; css = css->parent) { + cgrp = container_of(css, struct perf_cgroup, css); + info = this_cpu_ptr(cgrp->info); + + __update_cgrp_time(info, now, true); + if (final) + __store_release(&info->active, 0); + } + } +} + +static inline void update_cgrp_time_from_event(struct perf_event *event) +{ + struct perf_cgroup_info *info; + + /* + * ensure we access cgroup data only when needed and + * when we know the cgroup is pinned (css_get) + */ + if (!is_cgroup_event(event)) + return; + + info = this_cpu_ptr(event->cgrp->info); + /* + * Do not update time when cgroup is not active + */ + if (info->active) + __update_cgrp_time(info, perf_clock(), true); +} + +static inline void +perf_cgroup_set_timestamp(struct perf_cpu_context *cpuctx) +{ + struct perf_event_context *ctx = &cpuctx->ctx; + struct perf_cgroup *cgrp = cpuctx->cgrp; + struct perf_cgroup_info *info; + struct cgroup_subsys_state *css; + + /* + * ctx->lock held by caller + * ensure we do not access cgroup data + * unless we have the cgroup pinned (css_get) + */ + if (!cgrp) + return; + + WARN_ON_ONCE(!ctx->nr_cgroups); + + for (css = &cgrp->css; css; css = css->parent) { + cgrp = container_of(css, struct perf_cgroup, css); + info = this_cpu_ptr(cgrp->info); + __update_cgrp_time(info, ctx->timestamp, false); + __store_release(&info->active, 1); + } +} + +static DEFINE_PER_CPU(struct list_head, cgrp_cpuctx_list); + +/* + * reschedule events based on the cgroup constraint of task. + */ +static void perf_cgroup_switch(struct task_struct *task) +{ + struct perf_cgroup *cgrp; + struct perf_cpu_context *cpuctx, *tmp; + struct list_head *list; + unsigned long flags; + + /* + * Disable interrupts and preemption to avoid this CPU's + * cgrp_cpuctx_entry to change under us. + */ + local_irq_save(flags); + + cgrp = perf_cgroup_from_task(task, NULL); + + list = this_cpu_ptr(&cgrp_cpuctx_list); + list_for_each_entry_safe(cpuctx, tmp, list, cgrp_cpuctx_entry) { + WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0); + if (READ_ONCE(cpuctx->cgrp) == cgrp) + continue; + + perf_ctx_lock(cpuctx, cpuctx->task_ctx); + perf_pmu_disable(cpuctx->ctx.pmu); + + cpu_ctx_sched_out(cpuctx, EVENT_ALL); + /* + * must not be done before ctxswout due + * to update_cgrp_time_from_cpuctx() in + * ctx_sched_out() + */ + cpuctx->cgrp = cgrp; + /* + * set cgrp before ctxsw in to allow + * perf_cgroup_set_timestamp() in ctx_sched_in() + * to not have to pass task around + */ + cpu_ctx_sched_in(cpuctx, EVENT_ALL); + + perf_pmu_enable(cpuctx->ctx.pmu); + perf_ctx_unlock(cpuctx, cpuctx->task_ctx); + } + + local_irq_restore(flags); +} + +static int perf_cgroup_ensure_storage(struct perf_event *event, + struct cgroup_subsys_state *css) +{ + struct perf_cpu_context *cpuctx; + struct perf_event **storage; + int cpu, heap_size, ret = 0; + + /* + * Allow storage to have sufficent space for an iterator for each + * possibly nested cgroup plus an iterator for events with no cgroup. + */ + for (heap_size = 1; css; css = css->parent) + heap_size++; + + for_each_possible_cpu(cpu) { + cpuctx = per_cpu_ptr(event->pmu->pmu_cpu_context, cpu); + if (heap_size <= cpuctx->heap_size) + continue; + + storage = kmalloc_node(heap_size * sizeof(struct perf_event *), + GFP_KERNEL, cpu_to_node(cpu)); + if (!storage) { + ret = -ENOMEM; + break; + } + + raw_spin_lock_irq(&cpuctx->ctx.lock); + if (cpuctx->heap_size < heap_size) { + swap(cpuctx->heap, storage); + if (storage == cpuctx->heap_default) + storage = NULL; + cpuctx->heap_size = heap_size; + } + raw_spin_unlock_irq(&cpuctx->ctx.lock); + + kfree(storage); + } + + return ret; +} + +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 fd f = fdget(fd); + int ret = 0; + + if (!f.file) + return -EBADF; + + css = css_tryget_online_from_dir(f.file->f_path.dentry, + &perf_event_cgrp_subsys); + if (IS_ERR(css)) { + ret = PTR_ERR(css); + goto out; + } + + ret = perf_cgroup_ensure_storage(event, css); + if (ret) + goto out; + + cgrp = container_of(css, struct perf_cgroup, css); + event->cgrp = cgrp; + + /* + * 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: + fdput(f); + return ret; +} + +static inline void +perf_cgroup_event_enable(struct perf_event *event, struct perf_event_context *ctx) +{ + struct perf_cpu_context *cpuctx; + + if (!is_cgroup_event(event)) + return; + + /* + * Because cgroup events are always per-cpu events, + * @ctx == &cpuctx->ctx. + */ + cpuctx = container_of(ctx, struct perf_cpu_context, ctx); + + if (ctx->nr_cgroups++) + return; + + cpuctx->cgrp = perf_cgroup_from_task(current, ctx); + list_add(&cpuctx->cgrp_cpuctx_entry, + per_cpu_ptr(&cgrp_cpuctx_list, event->cpu)); +} + +static inline void +perf_cgroup_event_disable(struct perf_event *event, struct perf_event_context *ctx) +{ + struct perf_cpu_context *cpuctx; + + if (!is_cgroup_event(event)) + return; + + /* + * Because cgroup events are always per-cpu events, + * @ctx == &cpuctx->ctx. + */ + cpuctx = container_of(ctx, struct perf_cpu_context, ctx); + + if (--ctx->nr_cgroups) + return; + + cpuctx->cgrp = NULL; + list_del(&cpuctx->cgrp_cpuctx_entry); +} + +#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 void update_cgrp_time_from_event(struct perf_event *event) +{ +} + +static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx, + bool final) +{ +} + +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 perf_cpu_context *cpuctx) +{ +} + +static inline u64 perf_cgroup_event_time(struct perf_event *event) +{ + return 0; +} + +static inline u64 perf_cgroup_event_time_now(struct perf_event *event, u64 now) +{ + return 0; +} + +static inline void +perf_cgroup_event_enable(struct perf_event *event, struct perf_event_context *ctx) +{ +} + +static inline void +perf_cgroup_event_disable(struct perf_event *event, struct perf_event_context *ctx) +{ +} + +static void perf_cgroup_switch(struct task_struct *task) +{ +} +#endif + +/* + * set default to be dependent on timer tick just + * like original code + */ +#define PERF_CPU_HRTIMER (1000 / HZ) +/* + * function must be called with interrupts disabled + */ +static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr) +{ + struct perf_cpu_context *cpuctx; + bool rotations; + + lockdep_assert_irqs_disabled(); + + cpuctx = container_of(hr, struct perf_cpu_context, hrtimer); + rotations = perf_rotate_context(cpuctx); + + raw_spin_lock(&cpuctx->hrtimer_lock); + if (rotations) + hrtimer_forward_now(hr, cpuctx->hrtimer_interval); + else + cpuctx->hrtimer_active = 0; + raw_spin_unlock(&cpuctx->hrtimer_lock); + + return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART; +} + +static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu) +{ + struct hrtimer *timer = &cpuctx->hrtimer; + struct pmu *pmu = cpuctx->ctx.pmu; + u64 interval; + + /* no multiplexing needed for SW PMU */ + if (pmu->task_ctx_nr == perf_sw_context) + return; + + /* + * check default is sane, if not set then force to + * default interval (1/tick) + */ + interval = pmu->hrtimer_interval_ms; + if (interval < 1) + interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER; + + cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval); + + raw_spin_lock_init(&cpuctx->hrtimer_lock); + hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED_HARD); + timer->function = perf_mux_hrtimer_handler; +} + +static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx) +{ + struct hrtimer *timer = &cpuctx->hrtimer; + struct pmu *pmu = cpuctx->ctx.pmu; + unsigned long flags; + + /* not for SW PMU */ + if (pmu->task_ctx_nr == perf_sw_context) + return 0; + + raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags); + if (!cpuctx->hrtimer_active) { + cpuctx->hrtimer_active = 1; + hrtimer_forward_now(timer, cpuctx->hrtimer_interval); + hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED_HARD); + } + raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags); + + return 0; +} + +static int perf_mux_hrtimer_restart_ipi(void *arg) +{ + return perf_mux_hrtimer_restart(arg); +} + +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, active_ctx_list); + +/* + * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and + * perf_event_task_tick() are fully serialized because they're strictly cpu + * affine and perf_event_ctx{activate,deactivate} are called with IRQs + * disabled, while perf_event_task_tick is called from IRQ context. + */ +static void perf_event_ctx_activate(struct perf_event_context *ctx) +{ + struct list_head *head = this_cpu_ptr(&active_ctx_list); + + lockdep_assert_irqs_disabled(); + + WARN_ON(!list_empty(&ctx->active_ctx_list)); + + list_add(&ctx->active_ctx_list, head); +} + +static void perf_event_ctx_deactivate(struct perf_event_context *ctx) +{ + lockdep_assert_irqs_disabled(); + + WARN_ON(list_empty(&ctx->active_ctx_list)); + + list_del_init(&ctx->active_ctx_list); +} + +static void get_ctx(struct perf_event_context *ctx) +{ + refcount_inc(&ctx->refcount); +} + +static void *alloc_task_ctx_data(struct pmu *pmu) +{ + if (pmu->task_ctx_cache) + return kmem_cache_zalloc(pmu->task_ctx_cache, GFP_KERNEL); + + return NULL; +} + +static void free_task_ctx_data(struct pmu *pmu, void *task_ctx_data) +{ + if (pmu->task_ctx_cache && task_ctx_data) + kmem_cache_free(pmu->task_ctx_cache, task_ctx_data); +} + +static void free_ctx(struct rcu_head *head) +{ + struct perf_event_context *ctx; + + ctx = container_of(head, struct perf_event_context, rcu_head); + free_task_ctx_data(ctx->pmu, ctx->task_ctx_data); + kfree(ctx); +} + +static void put_ctx(struct perf_event_context *ctx) +{ + if (refcount_dec_and_test(&ctx->refcount)) { + if (ctx->parent_ctx) + put_ctx(ctx->parent_ctx); + if (ctx->task && ctx->task != TASK_TOMBSTONE) + put_task_struct(ctx->task); + call_rcu(&ctx->rcu_head, free_ctx); + } +} + +/* + * Because of perf_event::ctx migration in sys_perf_event_open::move_group and + * perf_pmu_migrate_context() we need some magic. + * + * Those places that change perf_event::ctx will hold both + * perf_event_ctx::mutex of the 'old' and 'new' ctx value. + * + * Lock ordering is by mutex address. There are two other sites where + * perf_event_context::mutex nests and those are: + * + * - perf_event_exit_task_context() [ child , 0 ] + * perf_event_exit_event() + * put_event() [ parent, 1 ] + * + * - perf_event_init_context() [ parent, 0 ] + * inherit_task_group() + * inherit_group() + * inherit_event() + * perf_event_alloc() + * perf_init_event() + * perf_try_init_event() [ child , 1 ] + * + * While it appears there is an obvious deadlock here -- the parent and child + * nesting levels are inverted between the two. This is in fact safe because + * life-time rules separate them. That is an exiting task cannot fork, and a + * spawning task cannot (yet) exit. + * + * But remember that these are parent<->child context relations, and + * migration does not affect children, therefore these two orderings should not + * interact. + * + * The change in perf_event::ctx does not affect children (as claimed above) + * because the sys_perf_event_open() case will install a new event and break + * the ctx parent<->child relation, and perf_pmu_migrate_context() is only + * concerned with cpuctx and that doesn't have children. + * + * The places that change perf_event::ctx will issue: + * + * perf_remove_from_context(); + * synchronize_rcu(); + * perf_install_in_context(); + * + * to affect the change. The remove_from_context() + synchronize_rcu() should + * quiesce the event, after which we can install it in the new location. This + * means that only external vectors (perf_fops, prctl) can perturb the event + * while in transit. Therefore all such accessors should also acquire + * perf_event_context::mutex to serialize against this. + * + * However; because event->ctx can change while we're waiting to acquire + * ctx->mutex we must be careful and use the below perf_event_ctx_lock() + * function. + * + * Lock order: + * exec_update_lock + * task_struct::perf_event_mutex + * perf_event_context::mutex + * perf_event::child_mutex; + * perf_event_context::lock + * perf_event::mmap_mutex + * mmap_lock + * perf_addr_filters_head::lock + * + * cpu_hotplug_lock + * pmus_lock + * cpuctx->mutex / perf_event_context::mutex + */ +static struct perf_event_context * +perf_event_ctx_lock_nested(struct perf_event *event, int nesting) +{ + struct perf_event_context *ctx; + +again: + rcu_read_lock(); + ctx = READ_ONCE(event->ctx); + if (!refcount_inc_not_zero(&ctx->refcount)) { + rcu_read_unlock(); + goto again; + } + rcu_read_unlock(); + + mutex_lock_nested(&ctx->mutex, nesting); + if (event->ctx != ctx) { + mutex_unlock(&ctx->mutex); + put_ctx(ctx); + goto again; + } + + return ctx; +} + +static inline struct perf_event_context * +perf_event_ctx_lock(struct perf_event *event) +{ + return perf_event_ctx_lock_nested(event, 0); +} + +static void perf_event_ctx_unlock(struct perf_event *event, + struct perf_event_context *ctx) +{ + mutex_unlock(&ctx->mutex); + put_ctx(ctx); +} + +/* + * This must be done under the ctx->lock, such as to serialize against + * context_equiv(), therefore we cannot call put_ctx() since that might end up + * calling scheduler related locks and ctx->lock nests inside those. + */ +static __must_check struct perf_event_context * +unclone_ctx(struct perf_event_context *ctx) +{ + struct perf_event_context *parent_ctx = ctx->parent_ctx; + + lockdep_assert_held(&ctx->lock); + + if (parent_ctx) + ctx->parent_ctx = NULL; + ctx->generation++; + + return parent_ctx; +} + +static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p, + enum pid_type type) +{ + u32 nr; + /* + * only top level events have the pid namespace they were created in + */ + if (event->parent) + event = event->parent; + + nr = __task_pid_nr_ns(p, type, event->ns); + /* avoid -1 if it is idle thread or runs in another ns */ + if (!nr && !pid_alive(p)) + nr = -1; + return nr; +} + +static u32 perf_event_pid(struct perf_event *event, struct task_struct *p) +{ + return perf_event_pid_type(event, p, PIDTYPE_TGID); +} + +static u32 perf_event_tid(struct perf_event *event, struct task_struct *p) +{ + return perf_event_pid_type(event, p, PIDTYPE_PID); +} + +/* + * 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 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; + +retry: + /* + * One of the few rules of preemptible RCU is that one cannot do + * rcu_read_unlock() while holding a scheduler (or nested) lock when + * part of the read side critical section was irqs-enabled -- see + * rcu_read_unlock_special(). + * + * Since ctx->lock nests under rq->lock we must ensure the entire read + * side critical section has interrupts disabled. + */ + local_irq_save(*flags); + rcu_read_lock(); + 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(&ctx->lock); + if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) { + raw_spin_unlock(&ctx->lock); + rcu_read_unlock(); + local_irq_restore(*flags); + goto retry; + } + + if (ctx->task == TASK_TOMBSTONE || + !refcount_inc_not_zero(&ctx->refcount)) { + raw_spin_unlock(&ctx->lock); + ctx = NULL; + } else { + WARN_ON_ONCE(ctx->task != task); + } + } + rcu_read_unlock(); + if (!ctx) + local_irq_restore(*flags); + 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, bool adv) +{ + u64 now = perf_clock(); + + lockdep_assert_held(&ctx->lock); + + if (adv) + ctx->time += now - ctx->timestamp; + ctx->timestamp = now; + + /* + * The above: time' = time + (now - timestamp), can be re-arranged + * into: time` = now + (time - timestamp), which gives a single value + * offset to compute future time without locks on. + * + * See perf_event_time_now(), which can be used from NMI context where + * it's (obviously) not possible to acquire ctx->lock in order to read + * both the above values in a consistent manner. + */ + WRITE_ONCE(ctx->timeoffset, ctx->time - ctx->timestamp); +} + +static void update_context_time(struct perf_event_context *ctx) +{ + __update_context_time(ctx, true); +} + +static u64 perf_event_time(struct perf_event *event) +{ + struct perf_event_context *ctx = event->ctx; + + if (unlikely(!ctx)) + return 0; + + if (is_cgroup_event(event)) + return perf_cgroup_event_time(event); + + return ctx->time; +} + +static u64 perf_event_time_now(struct perf_event *event, u64 now) +{ + struct perf_event_context *ctx = event->ctx; + + if (unlikely(!ctx)) + return 0; + + if (is_cgroup_event(event)) + return perf_cgroup_event_time_now(event, now); + + if (!(__load_acquire(&ctx->is_active) & EVENT_TIME)) + return ctx->time; + + now += READ_ONCE(ctx->timeoffset); + return now; +} + +static enum event_type_t get_event_type(struct perf_event *event) +{ + struct perf_event_context *ctx = event->ctx; + enum event_type_t event_type; + + lockdep_assert_held(&ctx->lock); + + /* + * It's 'group type', really, because if our group leader is + * pinned, so are we. + */ + if (event->group_leader != event) + event = event->group_leader; + + event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE; + if (!ctx->task) + event_type |= EVENT_CPU; + + return event_type; +} + +/* + * Helper function to initialize event group nodes. + */ +static void init_event_group(struct perf_event *event) +{ + RB_CLEAR_NODE(&event->group_node); + event->group_index = 0; +} + +/* + * Extract pinned or flexible groups from the context + * based on event attrs bits. + */ +static struct perf_event_groups * +get_event_groups(struct perf_event *event, struct perf_event_context *ctx) +{ + if (event->attr.pinned) + return &ctx->pinned_groups; + else + return &ctx->flexible_groups; +} + +/* + * Helper function to initializes perf_event_group trees. + */ +static void perf_event_groups_init(struct perf_event_groups *groups) +{ + groups->tree = RB_ROOT; + groups->index = 0; +} + +static inline struct cgroup *event_cgroup(const struct perf_event *event) +{ + struct cgroup *cgroup = NULL; + +#ifdef CONFIG_CGROUP_PERF + if (event->cgrp) + cgroup = event->cgrp->css.cgroup; +#endif + + return cgroup; +} + +/* + * Compare function for event groups; + * + * Implements complex key that first sorts by CPU and then by virtual index + * which provides ordering when rotating groups for the same CPU. + */ +static __always_inline int +perf_event_groups_cmp(const int left_cpu, const struct cgroup *left_cgroup, + const u64 left_group_index, const struct perf_event *right) +{ + if (left_cpu < right->cpu) + return -1; + if (left_cpu > right->cpu) + return 1; + +#ifdef CONFIG_CGROUP_PERF + { + const struct cgroup *right_cgroup = event_cgroup(right); + + if (left_cgroup != right_cgroup) { + if (!left_cgroup) { + /* + * Left has no cgroup but right does, no + * cgroups come first. + */ + return -1; + } + if (!right_cgroup) { + /* + * Right has no cgroup but left does, no + * cgroups come first. + */ + return 1; + } + /* Two dissimilar cgroups, order by id. */ + if (cgroup_id(left_cgroup) < cgroup_id(right_cgroup)) + return -1; + + return 1; + } + } +#endif + + if (left_group_index < right->group_index) + return -1; + if (left_group_index > right->group_index) + return 1; + + return 0; +} + +#define __node_2_pe(node) \ + rb_entry((node), struct perf_event, group_node) + +static inline bool __group_less(struct rb_node *a, const struct rb_node *b) +{ + struct perf_event *e = __node_2_pe(a); + return perf_event_groups_cmp(e->cpu, event_cgroup(e), e->group_index, + __node_2_pe(b)) < 0; +} + +struct __group_key { + int cpu; + struct cgroup *cgroup; +}; + +static inline int __group_cmp(const void *key, const struct rb_node *node) +{ + const struct __group_key *a = key; + const struct perf_event *b = __node_2_pe(node); + + /* partial/subtree match: @cpu, @cgroup; ignore: @group_index */ + return perf_event_groups_cmp(a->cpu, a->cgroup, b->group_index, b); +} + +/* + * Insert @event into @groups' tree; using {@event->cpu, ++@groups->index} for + * key (see perf_event_groups_less). This places it last inside the CPU + * subtree. + */ +static void +perf_event_groups_insert(struct perf_event_groups *groups, + struct perf_event *event) +{ + event->group_index = ++groups->index; + + rb_add(&event->group_node, &groups->tree, __group_less); +} + +/* + * Helper function to insert event into the pinned or flexible groups. + */ +static void +add_event_to_groups(struct perf_event *event, struct perf_event_context *ctx) +{ + struct perf_event_groups *groups; + + groups = get_event_groups(event, ctx); + perf_event_groups_insert(groups, event); +} + +/* + * Delete a group from a tree. + */ +static void +perf_event_groups_delete(struct perf_event_groups *groups, + struct perf_event *event) +{ + WARN_ON_ONCE(RB_EMPTY_NODE(&event->group_node) || + RB_EMPTY_ROOT(&groups->tree)); + + rb_erase(&event->group_node, &groups->tree); + init_event_group(event); +} + +/* + * Helper function to delete event from its groups. + */ +static void +del_event_from_groups(struct perf_event *event, struct perf_event_context *ctx) +{ + struct perf_event_groups *groups; + + groups = get_event_groups(event, ctx); + perf_event_groups_delete(groups, event); +} + +/* + * Get the leftmost event in the cpu/cgroup subtree. + */ +static struct perf_event * +perf_event_groups_first(struct perf_event_groups *groups, int cpu, + struct cgroup *cgrp) +{ + struct __group_key key = { + .cpu = cpu, + .cgroup = cgrp, + }; + struct rb_node *node; + + node = rb_find_first(&key, &groups->tree, __group_cmp); + if (node) + return __node_2_pe(node); + + return NULL; +} + +/* + * Like rb_entry_next_safe() for the @cpu subtree. + */ +static struct perf_event * +perf_event_groups_next(struct perf_event *event) +{ + struct __group_key key = { + .cpu = event->cpu, + .cgroup = event_cgroup(event), + }; + struct rb_node *next; + + next = rb_next_match(&key, &event->group_node, __group_cmp); + if (next) + return __node_2_pe(next); + + return NULL; +} + +/* + * Iterate through the whole groups tree. + */ +#define perf_event_groups_for_each(event, groups) \ + for (event = rb_entry_safe(rb_first(&((groups)->tree)), \ + typeof(*event), group_node); event; \ + event = rb_entry_safe(rb_next(&event->group_node), \ + typeof(*event), group_node)) + +/* + * Add an 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) +{ + lockdep_assert_held(&ctx->lock); + + WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT); + event->attach_state |= PERF_ATTACH_CONTEXT; + + event->tstamp = perf_event_time(event); + + /* + * 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) { + event->group_caps = event->event_caps; + add_event_to_groups(event, ctx); + } + + list_add_rcu(&event->event_entry, &ctx->event_list); + ctx->nr_events++; + if (event->hw.flags & PERF_EVENT_FLAG_USER_READ_CNT) + ctx->nr_user++; + if (event->attr.inherit_stat) + ctx->nr_stat++; + + if (event->state > PERF_EVENT_STATE_OFF) + perf_cgroup_event_enable(event, ctx); + + ctx->generation++; +} + +/* + * Initialize event state based on the perf_event_attr::disabled. + */ +static inline void perf_event__state_init(struct perf_event *event) +{ + event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF : + PERF_EVENT_STATE_INACTIVE; +} + +static int __perf_event_read_size(u64 read_format, int nr_siblings) +{ + int entry = sizeof(u64); /* value */ + int size = 0; + int nr = 1; + + if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) + size += sizeof(u64); + + if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) + size += sizeof(u64); + + if (read_format & PERF_FORMAT_ID) + entry += sizeof(u64); + + if (read_format & PERF_FORMAT_LOST) + entry += sizeof(u64); + + if (read_format & PERF_FORMAT_GROUP) { + nr += nr_siblings; + size += sizeof(u64); + } + + /* + * Since perf_event_validate_size() limits this to 16k and inhibits + * adding more siblings, this will never overflow. + */ + return size + nr * entry; +} + +static void __perf_event_header_size(struct perf_event *event, u64 sample_type) +{ + struct perf_sample_data *data; + u16 size = 0; + + 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_WEIGHT_TYPE) + size += sizeof(data->weight.full); + + if (sample_type & PERF_SAMPLE_READ) + size += event->read_size; + + if (sample_type & PERF_SAMPLE_DATA_SRC) + size += sizeof(data->data_src.val); + + if (sample_type & PERF_SAMPLE_TRANSACTION) + size += sizeof(data->txn); + + if (sample_type & PERF_SAMPLE_PHYS_ADDR) + size += sizeof(data->phys_addr); + + if (sample_type & PERF_SAMPLE_CGROUP) + size += sizeof(data->cgroup); + + if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE) + size += sizeof(data->data_page_size); + + if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE) + size += sizeof(data->code_page_size); + + event->header_size = size; +} + +/* + * Called at perf_event creation and when events are attached/detached from a + * group. + */ +static void perf_event__header_size(struct perf_event *event) +{ + event->read_size = + __perf_event_read_size(event->attr.read_format, + event->group_leader->nr_siblings); + __perf_event_header_size(event, event->attr.sample_type); +} + +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_IDENTIFIER) + size += sizeof(data->id); + + 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; +} + +/* + * Check that adding an event to the group does not result in anybody + * overflowing the 64k event limit imposed by the output buffer. + * + * Specifically, check that the read_size for the event does not exceed 16k, + * read_size being the one term that grows with groups size. Since read_size + * depends on per-event read_format, also (re)check the existing events. + * + * This leaves 48k for the constant size fields and things like callchains, + * branch stacks and register sets. + */ +static bool perf_event_validate_size(struct perf_event *event) +{ + struct perf_event *sibling, *group_leader = event->group_leader; + + if (__perf_event_read_size(event->attr.read_format, + group_leader->nr_siblings + 1) > 16*1024) + return false; + + if (__perf_event_read_size(group_leader->attr.read_format, + group_leader->nr_siblings + 1) > 16*1024) + return false; + + /* + * When creating a new group leader, group_leader->ctx is initialized + * after the size has been validated, but we cannot safely use + * for_each_sibling_event() until group_leader->ctx is set. A new group + * leader cannot have any siblings yet, so we can safely skip checking + * the non-existent siblings. + */ + if (event == group_leader) + return true; + + for_each_sibling_event(sibling, group_leader) { + if (__perf_event_read_size(sibling->attr.read_format, + group_leader->nr_siblings + 1) > 16*1024) + return false; + } + + return true; +} + +static void perf_group_attach(struct perf_event *event) +{ + struct perf_event *group_leader = event->group_leader, *pos; + + lockdep_assert_held(&event->ctx->lock); + + /* + * 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; + + WARN_ON_ONCE(group_leader->ctx != event->ctx); + + group_leader->group_caps &= event->event_caps; + + list_add_tail(&event->sibling_list, &group_leader->sibling_list); + group_leader->nr_siblings++; + group_leader->group_generation++; + + perf_event__header_size(group_leader); + + for_each_sibling_event(pos, group_leader) + perf_event__header_size(pos); +} + +/* + * Remove an 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) +{ + WARN_ON_ONCE(event->ctx != ctx); + lockdep_assert_held(&ctx->lock); + + /* + * 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; + + ctx->nr_events--; + if (event->hw.flags & PERF_EVENT_FLAG_USER_READ_CNT) + ctx->nr_user--; + if (event->attr.inherit_stat) + ctx->nr_stat--; + + list_del_rcu(&event->event_entry); + + if (event->group_leader == event) + del_event_from_groups(event, ctx); + + /* + * 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) { + perf_cgroup_event_disable(event, ctx); + perf_event_set_state(event, PERF_EVENT_STATE_OFF); + } + + ctx->generation++; +} + +static int +perf_aux_output_match(struct perf_event *event, struct perf_event *aux_event) +{ + if (!has_aux(aux_event)) + return 0; + + if (!event->pmu->aux_output_match) + return 0; + + return event->pmu->aux_output_match(aux_event); +} + +static void put_event(struct perf_event *event); +static void event_sched_out(struct perf_event *event, + struct perf_cpu_context *cpuctx, + struct perf_event_context *ctx); + +static void perf_put_aux_event(struct perf_event *event) +{ + struct perf_event_context *ctx = event->ctx; + struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); + struct perf_event *iter; + + /* + * If event uses aux_event tear down the link + */ + if (event->aux_event) { + iter = event->aux_event; + event->aux_event = NULL; + put_event(iter); + return; + } + + /* + * If the event is an aux_event, tear down all links to + * it from other events. + */ + for_each_sibling_event(iter, event->group_leader) { + if (iter->aux_event != event) + continue; + + iter->aux_event = NULL; + put_event(event); + + /* + * If it's ACTIVE, schedule it out and put it into ERROR + * state so that we don't try to schedule it again. Note + * that perf_event_enable() will clear the ERROR status. + */ + event_sched_out(iter, cpuctx, ctx); + perf_event_set_state(event, PERF_EVENT_STATE_ERROR); + } +} + +static bool perf_need_aux_event(struct perf_event *event) +{ + return !!event->attr.aux_output || !!event->attr.aux_sample_size; +} + +static int perf_get_aux_event(struct perf_event *event, + struct perf_event *group_leader) +{ + /* + * Our group leader must be an aux event if we want to be + * an aux_output. This way, the aux event will precede its + * aux_output events in the group, and therefore will always + * schedule first. + */ + if (!group_leader) + return 0; + + /* + * aux_output and aux_sample_size are mutually exclusive. + */ + if (event->attr.aux_output && event->attr.aux_sample_size) + return 0; + + if (event->attr.aux_output && + !perf_aux_output_match(event, group_leader)) + return 0; + + if (event->attr.aux_sample_size && !group_leader->pmu->snapshot_aux) + return 0; + + if (!atomic_long_inc_not_zero(&group_leader->refcount)) + return 0; + + /* + * Link aux_outputs to their aux event; this is undone in + * perf_group_detach() by perf_put_aux_event(). When the + * group in torn down, the aux_output events loose their + * link to the aux_event and can't schedule any more. + */ + event->aux_event = group_leader; + + return 1; +} + +static inline struct list_head *get_event_list(struct perf_event *event) +{ + struct perf_event_context *ctx = event->ctx; + return event->attr.pinned ? &ctx->pinned_active : &ctx->flexible_active; +} + +/* + * Events that have PERF_EV_CAP_SIBLING require being part of a group and + * cannot exist on their own, schedule them out and move them into the ERROR + * state. Also see _perf_event_enable(), it will not be able to recover + * this ERROR state. + */ +static inline void perf_remove_sibling_event(struct perf_event *event) +{ + struct perf_event_context *ctx = event->ctx; + struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); + + event_sched_out(event, cpuctx, ctx); + perf_event_set_state(event, PERF_EVENT_STATE_ERROR); +} + +static void perf_group_detach(struct perf_event *event) +{ + struct perf_event *leader = event->group_leader; + struct perf_event *sibling, *tmp; + struct perf_event_context *ctx = event->ctx; + + lockdep_assert_held(&ctx->lock); + + /* + * 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; + + perf_put_aux_event(event); + + /* + * If this is a sibling, remove it from its group. + */ + if (leader != event) { + list_del_init(&event->sibling_list); + event->group_leader->nr_siblings--; + event->group_leader->group_generation++; + goto out; + } + + /* + * 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, sibling_list) { + + if (sibling->event_caps & PERF_EV_CAP_SIBLING) + perf_remove_sibling_event(sibling); + + sibling->group_leader = sibling; + list_del_init(&sibling->sibling_list); + + /* Inherit group flags from the previous leader */ + sibling->group_caps = event->group_caps; + + if (sibling->attach_state & PERF_ATTACH_CONTEXT) { + add_event_to_groups(sibling, event->ctx); + + if (sibling->state == PERF_EVENT_STATE_ACTIVE) + list_add_tail(&sibling->active_list, get_event_list(sibling)); + } + + WARN_ON_ONCE(sibling->ctx != event->ctx); + } + +out: + for_each_sibling_event(tmp, leader) + perf_event__header_size(tmp); + + perf_event__header_size(leader); +} + +static void sync_child_event(struct perf_event *child_event); + +static void perf_child_detach(struct perf_event *event) +{ + struct perf_event *parent_event = event->parent; + + if (!(event->attach_state & PERF_ATTACH_CHILD)) + return; + + event->attach_state &= ~PERF_ATTACH_CHILD; + + if (WARN_ON_ONCE(!parent_event)) + return; + + lockdep_assert_held(&parent_event->child_mutex); + + sync_child_event(event); + list_del_init(&event->child_list); +} + +static bool is_orphaned_event(struct perf_event *event) +{ + return event->state == PERF_EVENT_STATE_DEAD; +} + +static inline int __pmu_filter_match(struct perf_event *event) +{ + struct pmu *pmu = event->pmu; + return pmu->filter_match ? pmu->filter_match(event) : 1; +} + +/* + * Check whether we should attempt to schedule an event group based on + * PMU-specific filtering. An event group can consist of HW and SW events, + * potentially with a SW leader, so we must check all the filters, to + * determine whether a group is schedulable: + */ +static inline int pmu_filter_match(struct perf_event *event) +{ + struct perf_event *sibling; + unsigned long flags; + int ret = 1; + + if (!__pmu_filter_match(event)) + return 0; + + local_irq_save(flags); + for_each_sibling_event(sibling, event) { + if (!__pmu_filter_match(sibling)) { + ret = 0; + break; + } + } + local_irq_restore(flags); + + return ret; +} + +static inline int +event_filter_match(struct perf_event *event) +{ + return (event->cpu == -1 || event->cpu == smp_processor_id()) && + perf_cgroup_match(event) && pmu_filter_match(event); +} + +static void +event_sched_out(struct perf_event *event, + struct perf_cpu_context *cpuctx, + struct perf_event_context *ctx) +{ + enum perf_event_state state = PERF_EVENT_STATE_INACTIVE; + + WARN_ON_ONCE(event->ctx != ctx); + lockdep_assert_held(&ctx->lock); + + if (event->state != PERF_EVENT_STATE_ACTIVE) + return; + + /* + * Asymmetry; we only schedule events _IN_ through ctx_sched_in(), but + * we can schedule events _OUT_ individually through things like + * __perf_remove_from_context(). + */ + list_del_init(&event->active_list); + + perf_pmu_disable(event->pmu); + + event->pmu->del(event, 0); + event->oncpu = -1; + + if (event->pending_disable) { + event->pending_disable = 0; + perf_cgroup_event_disable(event, ctx); + state = PERF_EVENT_STATE_OFF; + } + + if (event->pending_sigtrap) { + bool dec = true; + + event->pending_sigtrap = 0; + if (state != PERF_EVENT_STATE_OFF && + !event->pending_work) { + event->pending_work = 1; + dec = false; + WARN_ON_ONCE(!atomic_long_inc_not_zero(&event->refcount)); + task_work_add(current, &event->pending_task, TWA_RESUME); + } + if (dec) + local_dec(&event->ctx->nr_pending); + } + + perf_event_set_state(event, state); + + if (!is_software_event(event)) + cpuctx->active_oncpu--; + if (!--ctx->nr_active) + perf_event_ctx_deactivate(ctx); + if (event->attr.freq && event->attr.sample_freq) + ctx->nr_freq--; + if (event->attr.exclusive || !cpuctx->active_oncpu) + cpuctx->exclusive = 0; + + perf_pmu_enable(event->pmu); +} + +static void +group_sched_out(struct perf_event *group_event, + struct perf_cpu_context *cpuctx, + struct perf_event_context *ctx) +{ + struct perf_event *event; + + if (group_event->state != PERF_EVENT_STATE_ACTIVE) + return; + + perf_pmu_disable(ctx->pmu); + + event_sched_out(group_event, cpuctx, ctx); + + /* + * Schedule out siblings (if any): + */ + for_each_sibling_event(event, group_event) + event_sched_out(event, cpuctx, ctx); + + perf_pmu_enable(ctx->pmu); +} + +#define DETACH_GROUP 0x01UL +#define DETACH_CHILD 0x02UL +#define DETACH_DEAD 0x04UL + +/* + * 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 void +__perf_remove_from_context(struct perf_event *event, + struct perf_cpu_context *cpuctx, + struct perf_event_context *ctx, + void *info) +{ + unsigned long flags = (unsigned long)info; + + if (ctx->is_active & EVENT_TIME) { + update_context_time(ctx); + update_cgrp_time_from_cpuctx(cpuctx, false); + } + + /* + * Ensure event_sched_out() switches to OFF, at the very least + * this avoids raising perf_pending_task() at this time. + */ + if (flags & DETACH_DEAD) + event->pending_disable = 1; + event_sched_out(event, cpuctx, ctx); + if (flags & DETACH_GROUP) + perf_group_detach(event); + if (flags & DETACH_CHILD) + perf_child_detach(event); + list_del_event(event, ctx); + if (flags & DETACH_DEAD) + event->state = PERF_EVENT_STATE_DEAD; + + if (!ctx->nr_events && ctx->is_active) { + if (ctx == &cpuctx->ctx) + update_cgrp_time_from_cpuctx(cpuctx, true); + + ctx->is_active = 0; + ctx->rotate_necessary = 0; + if (ctx->task) { + WARN_ON_ONCE(cpuctx->task_ctx != ctx); + cpuctx->task_ctx = NULL; + } + } +} + +/* + * Remove the event from a task's (or a CPU's) list of events. + * + * 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, unsigned long flags) +{ + struct perf_event_context *ctx = event->ctx; + + lockdep_assert_held(&ctx->mutex); + + /* + * Because of perf_event_exit_task(), perf_remove_from_context() ought + * to work in the face of TASK_TOMBSTONE, unlike every other + * event_function_call() user. + */ + raw_spin_lock_irq(&ctx->lock); + /* + * Cgroup events are per-cpu events, and must IPI because of + * cgrp_cpuctx_list. + */ + if (!ctx->is_active && !is_cgroup_event(event)) { + __perf_remove_from_context(event, __get_cpu_context(ctx), + ctx, (void *)flags); + raw_spin_unlock_irq(&ctx->lock); + return; + } + raw_spin_unlock_irq(&ctx->lock); + + event_function_call(event, __perf_remove_from_context, (void *)flags); +} + +/* + * Cross CPU call to disable a performance event + */ +static void __perf_event_disable(struct perf_event *event, + struct perf_cpu_context *cpuctx, + struct perf_event_context *ctx, + void *info) +{ + if (event->state < PERF_EVENT_STATE_INACTIVE) + return; + + if (ctx->is_active & EVENT_TIME) { + update_context_time(ctx); + update_cgrp_time_from_event(event); + } + + if (event == event->group_leader) + group_sched_out(event, cpuctx, ctx); + else + event_sched_out(event, cpuctx, ctx); + + perf_event_set_state(event, PERF_EVENT_STATE_OFF); + perf_cgroup_event_disable(event, ctx); +} + +/* + * Disable an 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 because they + * hold the top-level event's child_mutex, so any descendant that + * goes to exit will block in perf_event_exit_event(). + * + * When called from perf_pending_irq 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. + */ +static void _perf_event_disable(struct perf_event *event) +{ + struct perf_event_context *ctx = event->ctx; + + raw_spin_lock_irq(&ctx->lock); + if (event->state <= PERF_EVENT_STATE_OFF) { + raw_spin_unlock_irq(&ctx->lock); + return; + } + raw_spin_unlock_irq(&ctx->lock); + + event_function_call(event, __perf_event_disable, NULL); +} + +void perf_event_disable_local(struct perf_event *event) +{ + event_function_local(event, __perf_event_disable, NULL); +} + +/* + * Strictly speaking kernel users cannot create groups and therefore this + * interface does not need the perf_event_ctx_lock() magic. + */ +void perf_event_disable(struct perf_event *event) +{ + struct perf_event_context *ctx; + + ctx = perf_event_ctx_lock(event); + _perf_event_disable(event); + perf_event_ctx_unlock(event, ctx); +} +EXPORT_SYMBOL_GPL(perf_event_disable); + +void perf_event_disable_inatomic(struct perf_event *event) +{ + event->pending_disable = 1; + irq_work_queue(&event->pending_irq); +} + +#define MAX_INTERRUPTS (~0ULL) + +static void perf_log_throttle(struct perf_event *event, int enable); +static void perf_log_itrace_start(struct perf_event *event); + +static int +event_sched_in(struct perf_event *event, + struct perf_cpu_context *cpuctx, + struct perf_event_context *ctx) +{ + int ret = 0; + + WARN_ON_ONCE(event->ctx != ctx); + + lockdep_assert_held(&ctx->lock); + + if (event->state <= PERF_EVENT_STATE_OFF) + return 0; + + WRITE_ONCE(event->oncpu, smp_processor_id()); + /* + * Order event::oncpu write to happen before the ACTIVE state is + * visible. This allows perf_event_{stop,read}() to observe the correct + * ->oncpu if it sees ACTIVE. + */ + smp_wmb(); + perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE); + + /* + * 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; + } + + perf_pmu_disable(event->pmu); + + perf_log_itrace_start(event); + + if (event->pmu->add(event, PERF_EF_START)) { + perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE); + event->oncpu = -1; + ret = -EAGAIN; + goto out; + } + + if (!is_software_event(event)) + cpuctx->active_oncpu++; + if (!ctx->nr_active++) + perf_event_ctx_activate(ctx); + if (event->attr.freq && event->attr.sample_freq) + ctx->nr_freq++; + + if (event->attr.exclusive) + cpuctx->exclusive = 1; + +out: + perf_pmu_enable(event->pmu); + + return ret; +} + +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 = ctx->pmu; + + if (group_event->state == PERF_EVENT_STATE_OFF) + return 0; + + pmu->start_txn(pmu, PERF_PMU_TXN_ADD); + + if (event_sched_in(group_event, cpuctx, ctx)) + goto error; + + /* + * Schedule in siblings as one group (if any): + */ + for_each_sibling_event(event, group_event) { + 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. + */ + for_each_sibling_event(event, group_event) { + if (event == partial_group) + break; + + event_sched_out(event, cpuctx, ctx); + } + event_sched_out(group_event, cpuctx, ctx); + +error: + 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_caps & PERF_EV_CAP_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 && !list_empty(get_event_list(event))) + 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) +{ + list_add_event(event, ctx); + perf_group_attach(event); +} + +static void ctx_sched_out(struct perf_event_context *ctx, + struct perf_cpu_context *cpuctx, + enum event_type_t event_type); +static void +ctx_sched_in(struct perf_event_context *ctx, + struct perf_cpu_context *cpuctx, + enum event_type_t event_type); + +static void task_ctx_sched_out(struct perf_cpu_context *cpuctx, + struct perf_event_context *ctx, + enum event_type_t event_type) +{ + if (!cpuctx->task_ctx) + return; + + if (WARN_ON_ONCE(ctx != cpuctx->task_ctx)) + return; + + ctx_sched_out(ctx, cpuctx, event_type); +} + +static void perf_event_sched_in(struct perf_cpu_context *cpuctx, + struct perf_event_context *ctx) +{ + cpu_ctx_sched_in(cpuctx, EVENT_PINNED); + if (ctx) + ctx_sched_in(ctx, cpuctx, EVENT_PINNED); + cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE); + if (ctx) + ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE); +} + +/* + * We want to maintain the following priority of scheduling: + * - CPU pinned (EVENT_CPU | EVENT_PINNED) + * - task pinned (EVENT_PINNED) + * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE) + * - task flexible (EVENT_FLEXIBLE). + * + * In order to avoid unscheduling and scheduling back in everything every + * time an event is added, only do it for the groups of equal priority and + * below. + * + * This can be called after a batch operation on task events, in which case + * event_type is a bit mask of the types of events involved. For CPU events, + * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE. + */ +static void ctx_resched(struct perf_cpu_context *cpuctx, + struct perf_event_context *task_ctx, + enum event_type_t event_type) +{ + enum event_type_t ctx_event_type; + bool cpu_event = !!(event_type & EVENT_CPU); + + /* + * If pinned groups are involved, flexible groups also need to be + * scheduled out. + */ + if (event_type & EVENT_PINNED) + event_type |= EVENT_FLEXIBLE; + + ctx_event_type = event_type & EVENT_ALL; + + perf_pmu_disable(cpuctx->ctx.pmu); + if (task_ctx) + task_ctx_sched_out(cpuctx, task_ctx, event_type); + + /* + * Decide which cpu ctx groups to schedule out based on the types + * of events that caused rescheduling: + * - EVENT_CPU: schedule out corresponding groups; + * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups; + * - otherwise, do nothing more. + */ + if (cpu_event) + cpu_ctx_sched_out(cpuctx, ctx_event_type); + else if (ctx_event_type & EVENT_PINNED) + cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); + + perf_event_sched_in(cpuctx, task_ctx); + perf_pmu_enable(cpuctx->ctx.pmu); +} + +void perf_pmu_resched(struct pmu *pmu) +{ + struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); + struct perf_event_context *task_ctx = cpuctx->task_ctx; + + perf_ctx_lock(cpuctx, task_ctx); + ctx_resched(cpuctx, task_ctx, EVENT_ALL|EVENT_CPU); + perf_ctx_unlock(cpuctx, task_ctx); +} + +/* + * Cross CPU call to install and enable a performance event + * + * Very similar to remote_function() + event_function() but cannot assume that + * things like ctx->is_active and cpuctx->task_ctx are set. + */ +static int __perf_install_in_context(void *info) +{ + struct perf_event *event = info; + struct perf_event_context *ctx = event->ctx; + struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); + struct perf_event_context *task_ctx = cpuctx->task_ctx; + bool reprogram = true; + int ret = 0; + + raw_spin_lock(&cpuctx->ctx.lock); + if (ctx->task) { + raw_spin_lock(&ctx->lock); + task_ctx = ctx; + + reprogram = (ctx->task == current); + + /* + * If the task is running, it must be running on this CPU, + * otherwise we cannot reprogram things. + * + * If its not running, we don't care, ctx->lock will + * serialize against it becoming runnable. + */ + if (task_curr(ctx->task) && !reprogram) { + ret = -ESRCH; + goto unlock; + } + + WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx); + } else if (task_ctx) { + raw_spin_lock(&task_ctx->lock); + } + +#ifdef CONFIG_CGROUP_PERF + if (event->state > PERF_EVENT_STATE_OFF && is_cgroup_event(event)) { + /* + * If the current cgroup doesn't match the event's + * cgroup, we should not try to schedule it. + */ + struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx); + reprogram = cgroup_is_descendant(cgrp->css.cgroup, + event->cgrp->css.cgroup); + } +#endif + + if (reprogram) { + ctx_sched_out(ctx, cpuctx, EVENT_TIME); + add_event_to_ctx(event, ctx); + ctx_resched(cpuctx, task_ctx, get_event_type(event)); + } else { + add_event_to_ctx(event, ctx); + } + +unlock: + perf_ctx_unlock(cpuctx, task_ctx); + + return ret; +} + +static bool exclusive_event_installable(struct perf_event *event, + struct perf_event_context *ctx); + +/* + * Attach a performance event to a context. + * + * Very similar to event_function_call, see comment there. + */ +static void +perf_install_in_context(struct perf_event_context *ctx, + struct perf_event *event, + int cpu) +{ + struct task_struct *task = READ_ONCE(ctx->task); + + lockdep_assert_held(&ctx->mutex); + + WARN_ON_ONCE(!exclusive_event_installable(event, ctx)); + + if (event->cpu != -1) + event->cpu = cpu; + + /* + * Ensures that if we can observe event->ctx, both the event and ctx + * will be 'complete'. See perf_iterate_sb_cpu(). + */ + smp_store_release(&event->ctx, ctx); + + /* + * perf_event_attr::disabled events will not run and can be initialized + * without IPI. Except when this is the first event for the context, in + * that case we need the magic of the IPI to set ctx->is_active. + * Similarly, cgroup events for the context also needs the IPI to + * manipulate the cgrp_cpuctx_list. + * + * The IOC_ENABLE that is sure to follow the creation of a disabled + * event will issue the IPI and reprogram the hardware. + */ + if (__perf_effective_state(event) == PERF_EVENT_STATE_OFF && + ctx->nr_events && !is_cgroup_event(event)) { + raw_spin_lock_irq(&ctx->lock); + if (ctx->task == TASK_TOMBSTONE) { + raw_spin_unlock_irq(&ctx->lock); + return; + } + add_event_to_ctx(event, ctx); + raw_spin_unlock_irq(&ctx->lock); + return; + } + + if (!task) { + cpu_function_call(cpu, __perf_install_in_context, event); + return; + } + + /* + * Should not happen, we validate the ctx is still alive before calling. + */ + if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) + return; + + /* + * Installing events is tricky because we cannot rely on ctx->is_active + * to be set in case this is the nr_events 0 -> 1 transition. + * + * Instead we use task_curr(), which tells us if the task is running. + * However, since we use task_curr() outside of rq::lock, we can race + * against the actual state. This means the result can be wrong. + * + * If we get a false positive, we retry, this is harmless. + * + * If we get a false negative, things are complicated. If we are after + * perf_event_context_sched_in() ctx::lock will serialize us, and the + * value must be correct. If we're before, it doesn't matter since + * perf_event_context_sched_in() will program the counter. + * + * However, this hinges on the remote context switch having observed + * our task->perf_event_ctxp[] store, such that it will in fact take + * ctx::lock in perf_event_context_sched_in(). + * + * We do this by task_function_call(), if the IPI fails to hit the task + * we know any future context switch of task must see the + * perf_event_ctpx[] store. + */ + + /* + * This smp_mb() orders the task->perf_event_ctxp[] store with the + * task_cpu() load, such that if the IPI then does not find the task + * running, a future context switch of that task must observe the + * store. + */ + smp_mb(); +again: + if (!task_function_call(task, __perf_install_in_context, event)) + return; + + raw_spin_lock_irq(&ctx->lock); + task = ctx->task; + if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) { + /* + * Cannot happen because we already checked above (which also + * cannot happen), and we hold ctx->mutex, which serializes us + * against perf_event_exit_task_context(). + */ + raw_spin_unlock_irq(&ctx->lock); + return; + } + /* + * If the task is not running, ctx->lock will avoid it becoming so, + * thus we can safely install the event. + */ + if (task_curr(task)) { + raw_spin_unlock_irq(&ctx->lock); + goto again; + } + add_event_to_ctx(event, ctx); + raw_spin_unlock_irq(&ctx->lock); +} + +/* + * Cross CPU call to enable a performance event + */ +static void __perf_event_enable(struct perf_event *event, + struct perf_cpu_context *cpuctx, + struct perf_event_context *ctx, + void *info) +{ + struct perf_event *leader = event->group_leader; + struct perf_event_context *task_ctx; + + if (event->state >= PERF_EVENT_STATE_INACTIVE || + event->state <= PERF_EVENT_STATE_ERROR) + return; + + if (ctx->is_active) + ctx_sched_out(ctx, cpuctx, EVENT_TIME); + + perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE); + perf_cgroup_event_enable(event, ctx); + + if (!ctx->is_active) + return; + + if (!event_filter_match(event)) { + ctx_sched_in(ctx, cpuctx, EVENT_TIME); + return; + } + + /* + * 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) { + ctx_sched_in(ctx, cpuctx, EVENT_TIME); + return; + } + + task_ctx = cpuctx->task_ctx; + if (ctx->task) + WARN_ON_ONCE(task_ctx != ctx); + + ctx_resched(cpuctx, task_ctx, get_event_type(event)); +} + +/* + * Enable an 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. + */ +static void _perf_event_enable(struct perf_event *event) +{ + struct perf_event_context *ctx = event->ctx; + + raw_spin_lock_irq(&ctx->lock); + if (event->state >= PERF_EVENT_STATE_INACTIVE || + event->state < PERF_EVENT_STATE_ERROR) { +out: + raw_spin_unlock_irq(&ctx->lock); + return; + } + + /* + * 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) { + /* + * Detached SIBLING events cannot leave ERROR state. + */ + if (event->event_caps & PERF_EV_CAP_SIBLING && + event->group_leader == event) + goto out; + + event->state = PERF_EVENT_STATE_OFF; + } + raw_spin_unlock_irq(&ctx->lock); + + event_function_call(event, __perf_event_enable, NULL); +} + +/* + * See perf_event_disable(); + */ +void perf_event_enable(struct perf_event *event) +{ + struct perf_event_context *ctx; + + ctx = perf_event_ctx_lock(event); + _perf_event_enable(event); + perf_event_ctx_unlock(event, ctx); +} +EXPORT_SYMBOL_GPL(perf_event_enable); + +struct stop_event_data { + struct perf_event *event; + unsigned int restart; +}; + +static int __perf_event_stop(void *info) +{ + struct stop_event_data *sd = info; + struct perf_event *event = sd->event; + + /* if it's already INACTIVE, do nothing */ + if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE) + return 0; + + /* matches smp_wmb() in event_sched_in() */ + smp_rmb(); + + /* + * There is a window with interrupts enabled before we get here, + * so we need to check again lest we try to stop another CPU's event. + */ + if (READ_ONCE(event->oncpu) != smp_processor_id()) + return -EAGAIN; + + event->pmu->stop(event, PERF_EF_UPDATE); + + /* + * May race with the actual stop (through perf_pmu_output_stop()), + * but it is only used for events with AUX ring buffer, and such + * events will refuse to restart because of rb::aux_mmap_count==0, + * see comments in perf_aux_output_begin(). + * + * Since this is happening on an event-local CPU, no trace is lost + * while restarting. + */ + if (sd->restart) + event->pmu->start(event, 0); + + return 0; +} + +static int perf_event_stop(struct perf_event *event, int restart) +{ + struct stop_event_data sd = { + .event = event, + .restart = restart, + }; + int ret = 0; + + do { + if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE) + return 0; + + /* matches smp_wmb() in event_sched_in() */ + smp_rmb(); + + /* + * We only want to restart ACTIVE events, so if the event goes + * inactive here (event->oncpu==-1), there's nothing more to do; + * fall through with ret==-ENXIO. + */ + ret = cpu_function_call(READ_ONCE(event->oncpu), + __perf_event_stop, &sd); + } while (ret == -EAGAIN); + + return ret; +} + +/* + * In order to contain the amount of racy and tricky in the address filter + * configuration management, it is a two part process: + * + * (p1) when userspace mappings change as a result of (1) or (2) or (3) below, + * we update the addresses of corresponding vmas in + * event::addr_filter_ranges array and bump the event::addr_filters_gen; + * (p2) when an event is scheduled in (pmu::add), it calls + * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync() + * if the generation has changed since the previous call. + * + * If (p1) happens while the event is active, we restart it to force (p2). + * + * (1) perf_addr_filters_apply(): adjusting filters' offsets based on + * pre-existing mappings, called once when new filters arrive via SET_FILTER + * ioctl; + * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly + * registered mapping, called for every new mmap(), with mm::mmap_lock down + * for reading; + * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process + * of exec. + */ +void perf_event_addr_filters_sync(struct perf_event *event) +{ + struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); + + if (!has_addr_filter(event)) + return; + + raw_spin_lock(&ifh->lock); + if (event->addr_filters_gen != event->hw.addr_filters_gen) { + event->pmu->addr_filters_sync(event); + event->hw.addr_filters_gen = event->addr_filters_gen; + } + raw_spin_unlock(&ifh->lock); +} +EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync); + +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; +} + +/* + * See perf_event_disable() + */ +int perf_event_refresh(struct perf_event *event, int refresh) +{ + struct perf_event_context *ctx; + int ret; + + ctx = perf_event_ctx_lock(event); + ret = _perf_event_refresh(event, refresh); + perf_event_ctx_unlock(event, ctx); + + return ret; +} +EXPORT_SYMBOL_GPL(perf_event_refresh); + +static int perf_event_modify_breakpoint(struct perf_event *bp, + struct perf_event_attr *attr) +{ + int err; + + _perf_event_disable(bp); + + err = modify_user_hw_breakpoint_check(bp, attr, true); + + if (!bp->attr.disabled) + _perf_event_enable(bp); + + return err; +} + +/* + * Copy event-type-independent attributes that may be modified. + */ +static void perf_event_modify_copy_attr(struct perf_event_attr *to, + const struct perf_event_attr *from) +{ + to->sig_data = from->sig_data; +} + +static int perf_event_modify_attr(struct perf_event *event, + struct perf_event_attr *attr) +{ + int (*func)(struct perf_event *, struct perf_event_attr *); + struct perf_event *child; + int err; + + if (event->attr.type != attr->type) + return -EINVAL; + + switch (event->attr.type) { + case PERF_TYPE_BREAKPOINT: + func = perf_event_modify_breakpoint; + break; + default: + /* Place holder for future additions. */ + return -EOPNOTSUPP; + } + + WARN_ON_ONCE(event->ctx->parent_ctx); + + mutex_lock(&event->child_mutex); + /* + * Event-type-independent attributes must be copied before event-type + * modification, which will validate that final attributes match the + * source attributes after all relevant attributes have been copied. + */ + perf_event_modify_copy_attr(&event->attr, attr); + err = func(event, attr); + if (err) + goto out; + list_for_each_entry(child, &event->child_list, child_list) { + perf_event_modify_copy_attr(&child->attr, attr); + err = func(child, attr); + if (err) + goto out; + } +out: + mutex_unlock(&event->child_mutex); + return err; +} + +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, *tmp; + int is_active = ctx->is_active; + + lockdep_assert_held(&ctx->lock); + + if (likely(!ctx->nr_events)) { + /* + * See __perf_remove_from_context(). + */ + WARN_ON_ONCE(ctx->is_active); + if (ctx->task) + WARN_ON_ONCE(cpuctx->task_ctx); + return; + } + + /* + * Always update time if it was set; not only when it changes. + * Otherwise we can 'forget' to update time for any but the last + * context we sched out. For example: + * + * ctx_sched_out(.event_type = EVENT_FLEXIBLE) + * ctx_sched_out(.event_type = EVENT_PINNED) + * + * would only update time for the pinned events. + */ + if (is_active & EVENT_TIME) { + /* update (and stop) ctx time */ + update_context_time(ctx); + update_cgrp_time_from_cpuctx(cpuctx, ctx == &cpuctx->ctx); + /* + * CPU-release for the below ->is_active store, + * see __load_acquire() in perf_event_time_now() + */ + barrier(); + } + + ctx->is_active &= ~event_type; + if (!(ctx->is_active & EVENT_ALL)) + ctx->is_active = 0; + + if (ctx->task) { + WARN_ON_ONCE(cpuctx->task_ctx != ctx); + if (!ctx->is_active) + cpuctx->task_ctx = NULL; + } + + is_active ^= ctx->is_active; /* changed bits */ + + if (!ctx->nr_active || !(is_active & EVENT_ALL)) + return; + + perf_pmu_disable(ctx->pmu); + if (is_active & EVENT_PINNED) { + list_for_each_entry_safe(event, tmp, &ctx->pinned_active, active_list) + group_sched_out(event, cpuctx, ctx); + } + + if (is_active & EVENT_FLEXIBLE) { + list_for_each_entry_safe(event, tmp, &ctx->flexible_active, active_list) + group_sched_out(event, cpuctx, ctx); + + /* + * Since we cleared EVENT_FLEXIBLE, also clear + * rotate_necessary, is will be reset by + * ctx_flexible_sched_in() when needed. + */ + ctx->rotate_necessary = 0; + } + perf_pmu_enable(ctx->pmu); +} + +/* + * Test whether two contexts are equivalent, i.e. whether they have both been + * cloned from the same version of the same context. + * + * Equivalence is measured using a generation number in the context that is + * incremented on each modification to it; see unclone_ctx(), list_add_event() + * and list_del_event(). + */ +static int context_equiv(struct perf_event_context *ctx1, + struct perf_event_context *ctx2) +{ + lockdep_assert_held(&ctx1->lock); + lockdep_assert_held(&ctx2->lock); + + /* Pinning disables the swap optimization */ + if (ctx1->pin_count || ctx2->pin_count) + return 0; + + /* If ctx1 is the parent of ctx2 */ + if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen) + return 1; + + /* If ctx2 is the parent of ctx1 */ + if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation) + return 1; + + /* + * If ctx1 and ctx2 have the same parent; we flatten the parent + * hierarchy, see perf_event_init_context(). + */ + if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx && + ctx1->parent_gen == ctx2->parent_gen) + return 1; + + /* Unmatched */ + return 0; +} + +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. + */ + if (event->state == PERF_EVENT_STATE_ACTIVE) + event->pmu->read(event); + + perf_event_update_time(event); + + /* + * 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); +} + +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, *next_parent; + struct perf_cpu_context *cpuctx; + int do_switch = 1; + struct pmu *pmu; + + if (likely(!ctx)) + return; + + pmu = ctx->pmu; + cpuctx = __get_cpu_context(ctx); + if (!cpuctx->task_ctx) + return; + + rcu_read_lock(); + next_ctx = next->perf_event_ctxp[ctxn]; + if (!next_ctx) + goto unlock; + + parent = rcu_dereference(ctx->parent_ctx); + next_parent = rcu_dereference(next_ctx->parent_ctx); + + /* If neither context have a parent context; they cannot be clones. */ + if (!parent && !next_parent) + goto unlock; + + if (next_parent == ctx || next_ctx == parent || next_parent == 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)) { + + perf_pmu_disable(pmu); + + /* PMIs are disabled; ctx->nr_pending is stable. */ + if (local_read(&ctx->nr_pending) || + local_read(&next_ctx->nr_pending)) { + /* + * Must not swap out ctx when there's pending + * events that rely on the ctx->task relation. + */ + raw_spin_unlock(&next_ctx->lock); + rcu_read_unlock(); + goto inside_switch; + } + + WRITE_ONCE(ctx->task, next); + WRITE_ONCE(next_ctx->task, task); + + if (cpuctx->sched_cb_usage && pmu->sched_task) + pmu->sched_task(ctx, false); + + /* + * PMU specific parts of task perf context can require + * additional synchronization. As an example of such + * synchronization see implementation details of Intel + * LBR call stack data profiling; + */ + if (pmu->swap_task_ctx) + pmu->swap_task_ctx(ctx, next_ctx); + else + swap(ctx->task_ctx_data, next_ctx->task_ctx_data); + + perf_pmu_enable(pmu); + + /* + * RCU_INIT_POINTER here is safe because we've not + * modified the ctx and the above modification of + * ctx->task and ctx->task_ctx_data are immaterial + * since those values are always verified under + * ctx->lock which we're now holding. + */ + RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx); + RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx); + + do_switch = 0; + + perf_event_sync_stat(ctx, next_ctx); + } + raw_spin_unlock(&next_ctx->lock); + raw_spin_unlock(&ctx->lock); + } +unlock: + rcu_read_unlock(); + + if (do_switch) { + raw_spin_lock(&ctx->lock); + perf_pmu_disable(pmu); + +inside_switch: + if (cpuctx->sched_cb_usage && pmu->sched_task) + pmu->sched_task(ctx, false); + task_ctx_sched_out(cpuctx, ctx, EVENT_ALL); + + perf_pmu_enable(pmu); + raw_spin_unlock(&ctx->lock); + } +} + +static DEFINE_PER_CPU(struct list_head, sched_cb_list); + +void perf_sched_cb_dec(struct pmu *pmu) +{ + struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); + + this_cpu_dec(perf_sched_cb_usages); + + if (!--cpuctx->sched_cb_usage) + list_del(&cpuctx->sched_cb_entry); +} + + +void perf_sched_cb_inc(struct pmu *pmu) +{ + struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); + + if (!cpuctx->sched_cb_usage++) + list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list)); + + this_cpu_inc(perf_sched_cb_usages); +} + +/* + * This function provides the context switch callback to the lower code + * layer. It is invoked ONLY when the context switch callback is enabled. + * + * This callback is relevant even to per-cpu events; for example multi event + * PEBS requires this to provide PID/TID information. This requires we flush + * all queued PEBS records before we context switch to a new task. + */ +static void __perf_pmu_sched_task(struct perf_cpu_context *cpuctx, bool sched_in) +{ + struct pmu *pmu; + + pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */ + + if (WARN_ON_ONCE(!pmu->sched_task)) + return; + + perf_ctx_lock(cpuctx, cpuctx->task_ctx); + perf_pmu_disable(pmu); + + pmu->sched_task(cpuctx->task_ctx, sched_in); + + perf_pmu_enable(pmu); + perf_ctx_unlock(cpuctx, cpuctx->task_ctx); +} + +static void perf_pmu_sched_task(struct task_struct *prev, + struct task_struct *next, + bool sched_in) +{ + struct perf_cpu_context *cpuctx; + + if (prev == next) + return; + + list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) { + /* will be handled in perf_event_context_sched_in/out */ + if (cpuctx->task_ctx) + continue; + + __perf_pmu_sched_task(cpuctx, sched_in); + } +} + +static void perf_event_switch(struct task_struct *task, + struct task_struct *next_prev, bool sched_in); + +#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; + + if (__this_cpu_read(perf_sched_cb_usages)) + perf_pmu_sched_task(task, next, false); + + if (atomic_read(&nr_switch_events)) + perf_event_switch(task, next, false); + + 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(this_cpu_ptr(&perf_cgroup_events))) + perf_cgroup_switch(next); +} + +/* + * 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 bool perf_less_group_idx(const void *l, const void *r) +{ + const struct perf_event *le = *(const struct perf_event **)l; + const struct perf_event *re = *(const struct perf_event **)r; + + return le->group_index < re->group_index; +} + +static void swap_ptr(void *l, void *r) +{ + void **lp = l, **rp = r; + + swap(*lp, *rp); +} + +static const struct min_heap_callbacks perf_min_heap = { + .elem_size = sizeof(struct perf_event *), + .less = perf_less_group_idx, + .swp = swap_ptr, +}; + +static void __heap_add(struct min_heap *heap, struct perf_event *event) +{ + struct perf_event **itrs = heap->data; + + if (event) { + itrs[heap->nr] = event; + heap->nr++; + } +} + +static noinline int visit_groups_merge(struct perf_cpu_context *cpuctx, + struct perf_event_groups *groups, int cpu, + int (*func)(struct perf_event *, void *), + void *data) +{ +#ifdef CONFIG_CGROUP_PERF + struct cgroup_subsys_state *css = NULL; +#endif + /* Space for per CPU and/or any CPU event iterators. */ + struct perf_event *itrs[2]; + struct min_heap event_heap; + struct perf_event **evt; + int ret; + + if (cpuctx) { + event_heap = (struct min_heap){ + .data = cpuctx->heap, + .nr = 0, + .size = cpuctx->heap_size, + }; + + lockdep_assert_held(&cpuctx->ctx.lock); + +#ifdef CONFIG_CGROUP_PERF + if (cpuctx->cgrp) + css = &cpuctx->cgrp->css; +#endif + } else { + event_heap = (struct min_heap){ + .data = itrs, + .nr = 0, + .size = ARRAY_SIZE(itrs), + }; + /* Events not within a CPU context may be on any CPU. */ + __heap_add(&event_heap, perf_event_groups_first(groups, -1, NULL)); + } + evt = event_heap.data; + + __heap_add(&event_heap, perf_event_groups_first(groups, cpu, NULL)); + +#ifdef CONFIG_CGROUP_PERF + for (; css; css = css->parent) + __heap_add(&event_heap, perf_event_groups_first(groups, cpu, css->cgroup)); +#endif + + min_heapify_all(&event_heap, &perf_min_heap); + + while (event_heap.nr) { + ret = func(*evt, data); + if (ret) + return ret; + + *evt = perf_event_groups_next(*evt); + if (*evt) + min_heapify(&event_heap, 0, &perf_min_heap); + else + min_heap_pop(&event_heap, &perf_min_heap); + } + + return 0; +} + +/* + * Because the userpage is strictly per-event (there is no concept of context, + * so there cannot be a context indirection), every userpage must be updated + * when context time starts :-( + * + * IOW, we must not miss EVENT_TIME edges. + */ +static inline bool event_update_userpage(struct perf_event *event) +{ + if (likely(!atomic_read(&event->mmap_count))) + return false; + + perf_event_update_time(event); + perf_event_update_userpage(event); + + return true; +} + +static inline void group_update_userpage(struct perf_event *group_event) +{ + struct perf_event *event; + + if (!event_update_userpage(group_event)) + return; + + for_each_sibling_event(event, group_event) + event_update_userpage(event); +} + +static int merge_sched_in(struct perf_event *event, void *data) +{ + struct perf_event_context *ctx = event->ctx; + struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); + int *can_add_hw = data; + + if (event->state <= PERF_EVENT_STATE_OFF) + return 0; + + if (!event_filter_match(event)) + return 0; + + if (group_can_go_on(event, cpuctx, *can_add_hw)) { + if (!group_sched_in(event, cpuctx, ctx)) + list_add_tail(&event->active_list, get_event_list(event)); + } + + if (event->state == PERF_EVENT_STATE_INACTIVE) { + *can_add_hw = 0; + if (event->attr.pinned) { + perf_cgroup_event_disable(event, ctx); + perf_event_set_state(event, PERF_EVENT_STATE_ERROR); + } else { + ctx->rotate_necessary = 1; + perf_mux_hrtimer_restart(cpuctx); + group_update_userpage(event); + } + } + + return 0; +} + +static void +ctx_pinned_sched_in(struct perf_event_context *ctx, + struct perf_cpu_context *cpuctx) +{ + int can_add_hw = 1; + + if (ctx != &cpuctx->ctx) + cpuctx = NULL; + + visit_groups_merge(cpuctx, &ctx->pinned_groups, + smp_processor_id(), + merge_sched_in, &can_add_hw); +} + +static void +ctx_flexible_sched_in(struct perf_event_context *ctx, + struct perf_cpu_context *cpuctx) +{ + int can_add_hw = 1; + + if (ctx != &cpuctx->ctx) + cpuctx = NULL; + + visit_groups_merge(cpuctx, &ctx->flexible_groups, + smp_processor_id(), + merge_sched_in, &can_add_hw); +} + +static void +ctx_sched_in(struct perf_event_context *ctx, + struct perf_cpu_context *cpuctx, + enum event_type_t event_type) +{ + int is_active = ctx->is_active; + + lockdep_assert_held(&ctx->lock); + + if (likely(!ctx->nr_events)) + return; + + if (!(is_active & EVENT_TIME)) { + /* start ctx time */ + __update_context_time(ctx, false); + perf_cgroup_set_timestamp(cpuctx); + /* + * CPU-release for the below ->is_active store, + * see __load_acquire() in perf_event_time_now() + */ + barrier(); + } + + ctx->is_active |= (event_type | EVENT_TIME); + if (ctx->task) { + if (!is_active) + cpuctx->task_ctx = ctx; + else + WARN_ON_ONCE(cpuctx->task_ctx != ctx); + } + + is_active ^= ctx->is_active; /* changed bits */ + + /* + * First go through the list and put on any pinned groups + * in order to give them the best chance of going on. + */ + if (is_active & EVENT_PINNED) + ctx_pinned_sched_in(ctx, cpuctx); + + /* Then walk through the lower prio flexible groups */ + if (is_active & EVENT_FLEXIBLE) + ctx_flexible_sched_in(ctx, cpuctx); +} + +static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx, + enum event_type_t event_type) +{ + struct perf_event_context *ctx = &cpuctx->ctx; + + ctx_sched_in(ctx, cpuctx, event_type); +} + +static void perf_event_context_sched_in(struct perf_event_context *ctx, + struct task_struct *task) +{ + struct perf_cpu_context *cpuctx; + struct pmu *pmu; + + cpuctx = __get_cpu_context(ctx); + + /* + * HACK: for HETEROGENEOUS the task context might have switched to a + * different PMU, force (re)set the context, + */ + pmu = ctx->pmu = cpuctx->ctx.pmu; + + if (cpuctx->task_ctx == ctx) { + if (cpuctx->sched_cb_usage) + __perf_pmu_sched_task(cpuctx, true); + return; + } + + perf_ctx_lock(cpuctx, ctx); + /* + * We must check ctx->nr_events while holding ctx->lock, such + * that we serialize against perf_install_in_context(). + */ + if (!ctx->nr_events) + goto unlock; + + perf_pmu_disable(pmu); + /* + * We want to keep the following priority order: + * cpu pinned (that don't need to move), task pinned, + * cpu flexible, task flexible. + * + * However, if task's ctx is not carrying any pinned + * events, no need to flip the cpuctx's events around. + */ + if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree)) + cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); + perf_event_sched_in(cpuctx, ctx); + + if (cpuctx->sched_cb_usage && pmu->sched_task) + pmu->sched_task(cpuctx->task_ctx, true); + + perf_pmu_enable(pmu); + +unlock: + perf_ctx_unlock(cpuctx, ctx); +} + +/* + * 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 *prev, + 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 (atomic_read(&nr_switch_events)) + perf_event_switch(task, prev, true); + + if (__this_cpu_read(perf_sched_cb_usages)) + perf_pmu_sched_task(prev, task, true); +} + +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 DEFINE_PER_CPU(int, perf_throttled_count); +static DEFINE_PER_CPU(u64, perf_throttled_seq); + +static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable) +{ + 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) { + if (disable) + event->pmu->stop(event, PERF_EF_UPDATE); + + local64_set(&hwc->period_left, 0); + + if (disable) + event->pmu->start(event, PERF_EF_RELOAD); + } +} + +/* + * combine freq adjustment with unthrottling to avoid two passes over the + * events. At the same time, make sure, having freq events does not change + * the rate of unthrottling as that would introduce bias. + */ +static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx, + int needs_unthr) +{ + struct perf_event *event; + struct hw_perf_event *hwc; + u64 now, period = TICK_NSEC; + s64 delta; + + /* + * only need to iterate over all events iff: + * - context have events in frequency mode (needs freq adjust) + * - there are events to unthrottle on this cpu + */ + if (!(ctx->nr_freq || needs_unthr)) + return; + + raw_spin_lock(&ctx->lock); + perf_pmu_disable(ctx->pmu); + + 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; + + perf_pmu_disable(event->pmu); + + hwc = &event->hw; + + if (hwc->interrupts == MAX_INTERRUPTS) { + hwc->interrupts = 0; + perf_log_throttle(event, 1); + event->pmu->start(event, 0); + } + + if (!event->attr.freq || !event->attr.sample_freq) + goto next; + + /* + * stop the event and update event->count + */ + event->pmu->stop(event, PERF_EF_UPDATE); + + now = local64_read(&event->count); + delta = now - hwc->freq_count_stamp; + hwc->freq_count_stamp = now; + + /* + * restart the event + * reload only if value has changed + * we have stopped the event so tell that + * to perf_adjust_period() to avoid stopping it + * twice. + */ + if (delta > 0) + perf_adjust_period(event, period, delta, false); + + event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0); + next: + perf_pmu_enable(event->pmu); + } + + perf_pmu_enable(ctx->pmu); + raw_spin_unlock(&ctx->lock); +} + +/* + * Move @event to the tail of the @ctx's elegible events. + */ +static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event) +{ + /* + * Rotate the first entry last of non-pinned groups. Rotation might be + * disabled by the inheritance code. + */ + if (ctx->rotate_disable) + return; + + perf_event_groups_delete(&ctx->flexible_groups, event); + perf_event_groups_insert(&ctx->flexible_groups, event); +} + +/* pick an event from the flexible_groups to rotate */ +static inline struct perf_event * +ctx_event_to_rotate(struct perf_event_context *ctx) +{ + struct perf_event *event; + + /* pick the first active flexible event */ + event = list_first_entry_or_null(&ctx->flexible_active, + struct perf_event, active_list); + + /* if no active flexible event, pick the first event */ + if (!event) { + event = rb_entry_safe(rb_first(&ctx->flexible_groups.tree), + typeof(*event), group_node); + } + + /* + * Unconditionally clear rotate_necessary; if ctx_flexible_sched_in() + * finds there are unschedulable events, it will set it again. + */ + ctx->rotate_necessary = 0; + + return event; +} + +static bool perf_rotate_context(struct perf_cpu_context *cpuctx) +{ + struct perf_event *cpu_event = NULL, *task_event = NULL; + struct perf_event_context *task_ctx = NULL; + int cpu_rotate, task_rotate; + + /* + * Since we run this from IRQ context, nobody can install new + * events, thus the event count values are stable. + */ + + cpu_rotate = cpuctx->ctx.rotate_necessary; + task_ctx = cpuctx->task_ctx; + task_rotate = task_ctx ? task_ctx->rotate_necessary : 0; + + if (!(cpu_rotate || task_rotate)) + return false; + + perf_ctx_lock(cpuctx, cpuctx->task_ctx); + perf_pmu_disable(cpuctx->ctx.pmu); + + if (task_rotate) + task_event = ctx_event_to_rotate(task_ctx); + if (cpu_rotate) + cpu_event = ctx_event_to_rotate(&cpuctx->ctx); + + /* + * As per the order given at ctx_resched() first 'pop' task flexible + * and then, if needed CPU flexible. + */ + if (task_event || (task_ctx && cpu_event)) + ctx_sched_out(task_ctx, cpuctx, EVENT_FLEXIBLE); + if (cpu_event) + cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); + + if (task_event) + rotate_ctx(task_ctx, task_event); + if (cpu_event) + rotate_ctx(&cpuctx->ctx, cpu_event); + + perf_event_sched_in(cpuctx, task_ctx); + + perf_pmu_enable(cpuctx->ctx.pmu); + perf_ctx_unlock(cpuctx, cpuctx->task_ctx); + + return true; +} + +void perf_event_task_tick(void) +{ + struct list_head *head = this_cpu_ptr(&active_ctx_list); + struct perf_event_context *ctx, *tmp; + int throttled; + + lockdep_assert_irqs_disabled(); + + __this_cpu_inc(perf_throttled_seq); + throttled = __this_cpu_xchg(perf_throttled_count, 0); + tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS); + + list_for_each_entry_safe(ctx, tmp, head, active_ctx_list) + perf_adjust_freq_unthr_context(ctx, throttled); +} + +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_set_state(event, PERF_EVENT_STATE_INACTIVE); + + 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(int ctxn) +{ + struct perf_event_context *ctx, *clone_ctx = NULL; + enum event_type_t event_type = 0; + struct perf_cpu_context *cpuctx; + struct perf_event *event; + unsigned long flags; + int enabled = 0; + + local_irq_save(flags); + ctx = current->perf_event_ctxp[ctxn]; + if (!ctx || !ctx->nr_events) + goto out; + + cpuctx = __get_cpu_context(ctx); + perf_ctx_lock(cpuctx, ctx); + ctx_sched_out(ctx, cpuctx, EVENT_TIME); + list_for_each_entry(event, &ctx->event_list, event_entry) { + enabled |= event_enable_on_exec(event, ctx); + event_type |= get_event_type(event); + } + + /* + * Unclone and reschedule this context if we enabled any event. + */ + if (enabled) { + clone_ctx = unclone_ctx(ctx); + ctx_resched(cpuctx, ctx, event_type); + } else { + ctx_sched_in(ctx, cpuctx, EVENT_TIME); + } + perf_ctx_unlock(cpuctx, ctx); + +out: + local_irq_restore(flags); + + if (clone_ctx) + put_ctx(clone_ctx); +} + +static void perf_remove_from_owner(struct perf_event *event); +static void perf_event_exit_event(struct perf_event *event, + struct perf_event_context *ctx); + +/* + * Removes all events from the current task that have been marked + * remove-on-exec, and feeds their values back to parent events. + */ +static void perf_event_remove_on_exec(int ctxn) +{ + struct perf_event_context *ctx, *clone_ctx = NULL; + struct perf_event *event, *next; + unsigned long flags; + bool modified = false; + + ctx = perf_pin_task_context(current, ctxn); + if (!ctx) + return; + + mutex_lock(&ctx->mutex); + + if (WARN_ON_ONCE(ctx->task != current)) + goto unlock; + + list_for_each_entry_safe(event, next, &ctx->event_list, event_entry) { + if (!event->attr.remove_on_exec) + continue; + + if (!is_kernel_event(event)) + perf_remove_from_owner(event); + + modified = true; + + perf_event_exit_event(event, ctx); + } + + raw_spin_lock_irqsave(&ctx->lock, flags); + if (modified) + clone_ctx = unclone_ctx(ctx); + --ctx->pin_count; + raw_spin_unlock_irqrestore(&ctx->lock, flags); + +unlock: + mutex_unlock(&ctx->mutex); + + put_ctx(ctx); + if (clone_ctx) + put_ctx(clone_ctx); +} + +struct perf_read_data { + struct perf_event *event; + bool group; + int ret; +}; + +static int __perf_event_read_cpu(struct perf_event *event, int event_cpu) +{ + u16 local_pkg, event_pkg; + + if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) { + int local_cpu = smp_processor_id(); + + event_pkg = topology_physical_package_id(event_cpu); + local_pkg = topology_physical_package_id(local_cpu); + + if (event_pkg == local_pkg) + return local_cpu; + } + + return event_cpu; +} + +/* + * Cross CPU call to read the hardware event + */ +static void __perf_event_read(void *info) +{ + struct perf_read_data *data = info; + struct perf_event *sub, *event = data->event; + struct perf_event_context *ctx = event->ctx; + struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); + struct pmu *pmu = event->pmu; + + /* + * 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 & EVENT_TIME) { + update_context_time(ctx); + update_cgrp_time_from_event(event); + } + + perf_event_update_time(event); + if (data->group) + perf_event_update_sibling_time(event); + + if (event->state != PERF_EVENT_STATE_ACTIVE) + goto unlock; + + if (!data->group) { + pmu->read(event); + data->ret = 0; + goto unlock; + } + + pmu->start_txn(pmu, PERF_PMU_TXN_READ); + + pmu->read(event); + + for_each_sibling_event(sub, event) { + if (sub->state == PERF_EVENT_STATE_ACTIVE) { + /* + * Use sibling's PMU rather than @event's since + * sibling could be on different (eg: software) PMU. + */ + sub->pmu->read(sub); + } + } + + data->ret = pmu->commit_txn(pmu); + +unlock: + 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 void calc_timer_values(struct perf_event *event, + u64 *now, + u64 *enabled, + u64 *running) +{ + u64 ctx_time; + + *now = perf_clock(); + ctx_time = perf_event_time_now(event, *now); + __perf_update_times(event, ctx_time, enabled, running); +} + +/* + * NMI-safe method to read a local event, that is an event that + * is: + * - either for the current task, or for this CPU + * - does not have inherit set, for inherited task events + * will not be local and we cannot read them atomically + * - must not have a pmu::count method + */ +int perf_event_read_local(struct perf_event *event, u64 *value, + u64 *enabled, u64 *running) +{ + unsigned long flags; + int ret = 0; + + /* + * Disabling interrupts avoids all counter scheduling (context + * switches, timer based rotation and IPIs). + */ + local_irq_save(flags); + + /* + * It must not be an event with inherit set, we cannot read + * all child counters from atomic context. + */ + if (event->attr.inherit) { + ret = -EOPNOTSUPP; + goto out; + } + + /* If this is a per-task event, it must be for current */ + if ((event->attach_state & PERF_ATTACH_TASK) && + event->hw.target != current) { + ret = -EINVAL; + goto out; + } + + /* If this is a per-CPU event, it must be for this CPU */ + if (!(event->attach_state & PERF_ATTACH_TASK) && + event->cpu != smp_processor_id()) { + ret = -EINVAL; + goto out; + } + + /* If this is a pinned event it must be running on this CPU */ + if (event->attr.pinned && event->oncpu != smp_processor_id()) { + ret = -EBUSY; + goto out; + } + + /* + * If the event is currently on this CPU, its either a per-task event, + * or local to this CPU. Furthermore it means its ACTIVE (otherwise + * oncpu == -1). + */ + if (event->oncpu == smp_processor_id()) + event->pmu->read(event); + + *value = local64_read(&event->count); + if (enabled || running) { + u64 __enabled, __running, __now; + + calc_timer_values(event, &__now, &__enabled, &__running); + if (enabled) + *enabled = __enabled; + if (running) + *running = __running; + } +out: + local_irq_restore(flags); + + return ret; +} + +static int perf_event_read(struct perf_event *event, bool group) +{ + enum perf_event_state state = READ_ONCE(event->state); + int event_cpu, ret = 0; + + /* + * If event is enabled and currently active on a CPU, update the + * value in the event structure: + */ +again: + if (state == PERF_EVENT_STATE_ACTIVE) { + struct perf_read_data data; + + /* + * Orders the ->state and ->oncpu loads such that if we see + * ACTIVE we must also see the right ->oncpu. + * + * Matches the smp_wmb() from event_sched_in(). + */ + smp_rmb(); + + event_cpu = READ_ONCE(event->oncpu); + if ((unsigned)event_cpu >= nr_cpu_ids) + return 0; + + data = (struct perf_read_data){ + .event = event, + .group = group, + .ret = 0, + }; + + preempt_disable(); + event_cpu = __perf_event_read_cpu(event, event_cpu); + + /* + * Purposely ignore the smp_call_function_single() return + * value. + * + * If event_cpu isn't a valid CPU it means the event got + * scheduled out and that will have updated the event count. + * + * Therefore, either way, we'll have an up-to-date event count + * after this. + */ + (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1); + preempt_enable(); + ret = data.ret; + + } else if (state == PERF_EVENT_STATE_INACTIVE) { + struct perf_event_context *ctx = event->ctx; + unsigned long flags; + + raw_spin_lock_irqsave(&ctx->lock, flags); + state = event->state; + if (state != PERF_EVENT_STATE_INACTIVE) { + raw_spin_unlock_irqrestore(&ctx->lock, flags); + goto again; + } + + /* + * May read while context is not active (e.g., thread is + * blocked), in that case we cannot update context time + */ + if (ctx->is_active & EVENT_TIME) { + update_context_time(ctx); + update_cgrp_time_from_event(event); + } + + perf_event_update_time(event); + if (group) + perf_event_update_sibling_time(event); + raw_spin_unlock_irqrestore(&ctx->lock, flags); + } + + return ret; +} + +/* + * 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->active_ctx_list); + perf_event_groups_init(&ctx->pinned_groups); + perf_event_groups_init(&ctx->flexible_groups); + INIT_LIST_HEAD(&ctx->event_list); + INIT_LIST_HEAD(&ctx->pinned_active); + INIT_LIST_HEAD(&ctx->flexible_active); + refcount_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 = 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; + + 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); + + return task; +} + +/* + * Returns a matching context with refcount and pincount. + */ +static struct perf_event_context * +find_get_context(struct pmu *pmu, struct task_struct *task, + struct perf_event *event) +{ + struct perf_event_context *ctx, *clone_ctx = NULL; + struct perf_cpu_context *cpuctx; + void *task_ctx_data = NULL; + unsigned long flags; + int ctxn, err; + int cpu = event->cpu; + + if (!task) { + /* Must be root to operate on a CPU event: */ + err = perf_allow_cpu(&event->attr); + if (err) + return ERR_PTR(err); + + cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); + ctx = &cpuctx->ctx; + get_ctx(ctx); + raw_spin_lock_irqsave(&ctx->lock, flags); + ++ctx->pin_count; + raw_spin_unlock_irqrestore(&ctx->lock, flags); + + return ctx; + } + + err = -EINVAL; + ctxn = pmu->task_ctx_nr; + if (ctxn < 0) + goto errout; + + if (event->attach_state & PERF_ATTACH_TASK_DATA) { + task_ctx_data = alloc_task_ctx_data(pmu); + if (!task_ctx_data) { + err = -ENOMEM; + goto errout; + } + } + +retry: + ctx = perf_lock_task_context(task, ctxn, &flags); + if (ctx) { + clone_ctx = unclone_ctx(ctx); + ++ctx->pin_count; + + if (task_ctx_data && !ctx->task_ctx_data) { + ctx->task_ctx_data = task_ctx_data; + task_ctx_data = NULL; + } + raw_spin_unlock_irqrestore(&ctx->lock, flags); + + if (clone_ctx) + put_ctx(clone_ctx); + } else { + ctx = alloc_perf_context(pmu, task); + err = -ENOMEM; + if (!ctx) + goto errout; + + if (task_ctx_data) { + ctx->task_ctx_data = task_ctx_data; + task_ctx_data = NULL; + } + + 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 { + get_ctx(ctx); + ++ctx->pin_count; + rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx); + } + mutex_unlock(&task->perf_event_mutex); + + if (unlikely(err)) { + put_ctx(ctx); + + if (err == -EAGAIN) + goto retry; + goto errout; + } + } + + free_task_ctx_data(pmu, task_ctx_data); + return ctx; + +errout: + free_task_ctx_data(pmu, task_ctx_data); + 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); + kmem_cache_free(perf_event_cache, event); +} + +static void ring_buffer_attach(struct perf_event *event, + struct perf_buffer *rb); + +static void detach_sb_event(struct perf_event *event) +{ + struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu); + + raw_spin_lock(&pel->lock); + list_del_rcu(&event->sb_list); + raw_spin_unlock(&pel->lock); +} + +static bool is_sb_event(struct perf_event *event) +{ + struct perf_event_attr *attr = &event->attr; + + if (event->parent) + return false; + + if (event->attach_state & PERF_ATTACH_TASK) + return false; + + if (attr->mmap || attr->mmap_data || attr->mmap2 || + attr->comm || attr->comm_exec || + attr->task || attr->ksymbol || + attr->context_switch || attr->text_poke || + attr->bpf_event) + return true; + return false; +} + +static void unaccount_pmu_sb_event(struct perf_event *event) +{ + if (is_sb_event(event)) + detach_sb_event(event); +} + +static void unaccount_event_cpu(struct perf_event *event, int cpu) +{ + if (event->parent) + return; + + if (is_cgroup_event(event)) + atomic_dec(&per_cpu(perf_cgroup_events, cpu)); +} + +#ifdef CONFIG_NO_HZ_FULL +static DEFINE_SPINLOCK(nr_freq_lock); +#endif + +static void unaccount_freq_event_nohz(void) +{ +#ifdef CONFIG_NO_HZ_FULL + spin_lock(&nr_freq_lock); + if (atomic_dec_and_test(&nr_freq_events)) + tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS); + spin_unlock(&nr_freq_lock); +#endif +} + +static void unaccount_freq_event(void) +{ + if (tick_nohz_full_enabled()) + unaccount_freq_event_nohz(); + else + atomic_dec(&nr_freq_events); +} + +static void unaccount_event(struct perf_event *event) +{ + bool dec = false; + + if (event->parent) + return; + + if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB)) + dec = true; + if (event->attr.mmap || event->attr.mmap_data) + atomic_dec(&nr_mmap_events); + if (event->attr.build_id) + atomic_dec(&nr_build_id_events); + if (event->attr.comm) + atomic_dec(&nr_comm_events); + if (event->attr.namespaces) + atomic_dec(&nr_namespaces_events); + if (event->attr.cgroup) + atomic_dec(&nr_cgroup_events); + if (event->attr.task) + atomic_dec(&nr_task_events); + if (event->attr.freq) + unaccount_freq_event(); + if (event->attr.context_switch) { + dec = true; + atomic_dec(&nr_switch_events); + } + if (is_cgroup_event(event)) + dec = true; + if (has_branch_stack(event)) + dec = true; + if (event->attr.ksymbol) + atomic_dec(&nr_ksymbol_events); + if (event->attr.bpf_event) + atomic_dec(&nr_bpf_events); + if (event->attr.text_poke) + atomic_dec(&nr_text_poke_events); + + if (dec) { + if (!atomic_add_unless(&perf_sched_count, -1, 1)) + schedule_delayed_work(&perf_sched_work, HZ); + } + + unaccount_event_cpu(event, event->cpu); + + unaccount_pmu_sb_event(event); +} + +static void perf_sched_delayed(struct work_struct *work) +{ + mutex_lock(&perf_sched_mutex); + if (atomic_dec_and_test(&perf_sched_count)) + static_branch_disable(&perf_sched_events); + mutex_unlock(&perf_sched_mutex); +} + +/* + * The following implement mutual exclusion of events on "exclusive" pmus + * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled + * at a time, so we disallow creating events that might conflict, namely: + * + * 1) cpu-wide events in the presence of per-task events, + * 2) per-task events in the presence of cpu-wide events, + * 3) two matching events on the same context. + * + * The former two cases are handled in the allocation path (perf_event_alloc(), + * _free_event()), the latter -- before the first perf_install_in_context(). + */ +static int exclusive_event_init(struct perf_event *event) +{ + struct pmu *pmu = event->pmu; + + if (!is_exclusive_pmu(pmu)) + return 0; + + /* + * Prevent co-existence of per-task and cpu-wide events on the + * same exclusive pmu. + * + * Negative pmu::exclusive_cnt means there are cpu-wide + * events on this "exclusive" pmu, positive means there are + * per-task events. + * + * Since this is called in perf_event_alloc() path, event::ctx + * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK + * to mean "per-task event", because unlike other attach states it + * never gets cleared. + */ + if (event->attach_state & PERF_ATTACH_TASK) { + if (!atomic_inc_unless_negative(&pmu->exclusive_cnt)) + return -EBUSY; + } else { + if (!atomic_dec_unless_positive(&pmu->exclusive_cnt)) + return -EBUSY; + } + + return 0; +} + +static void exclusive_event_destroy(struct perf_event *event) +{ + struct pmu *pmu = event->pmu; + + if (!is_exclusive_pmu(pmu)) + return; + + /* see comment in exclusive_event_init() */ + if (event->attach_state & PERF_ATTACH_TASK) + atomic_dec(&pmu->exclusive_cnt); + else + atomic_inc(&pmu->exclusive_cnt); +} + +static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2) +{ + if ((e1->pmu == e2->pmu) && + (e1->cpu == e2->cpu || + e1->cpu == -1 || + e2->cpu == -1)) + return true; + return false; +} + +static bool exclusive_event_installable(struct perf_event *event, + struct perf_event_context *ctx) +{ + struct perf_event *iter_event; + struct pmu *pmu = event->pmu; + + lockdep_assert_held(&ctx->mutex); + + if (!is_exclusive_pmu(pmu)) + return true; + + list_for_each_entry(iter_event, &ctx->event_list, event_entry) { + if (exclusive_event_match(iter_event, event)) + return false; + } + + return true; +} + +static void perf_addr_filters_splice(struct perf_event *event, + struct list_head *head); + +static void _free_event(struct perf_event *event) +{ + irq_work_sync(&event->pending_irq); + + unaccount_event(event); + + security_perf_event_free(event); + + if (event->rb) { + /* + * Can happen when we close an event with re-directed output. + * + * Since we have a 0 refcount, perf_mmap_close() will skip + * over us; possibly making our ring_buffer_put() the last. + */ + mutex_lock(&event->mmap_mutex); + ring_buffer_attach(event, NULL); + mutex_unlock(&event->mmap_mutex); + } + + if (is_cgroup_event(event)) + perf_detach_cgroup(event); + + if (!event->parent) { + if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) + put_callchain_buffers(); + } + + perf_event_free_bpf_prog(event); + perf_addr_filters_splice(event, NULL); + kfree(event->addr_filter_ranges); + + if (event->destroy) + event->destroy(event); + + /* + * Must be after ->destroy(), due to uprobe_perf_close() using + * hw.target. + */ + if (event->hw.target) + put_task_struct(event->hw.target); + + /* + * perf_event_free_task() relies on put_ctx() being 'last', in particular + * all task references must be cleaned up. + */ + if (event->ctx) + put_ctx(event->ctx); + + exclusive_event_destroy(event); + module_put(event->pmu->module); + + call_rcu(&event->rcu_head, free_event_rcu); +} + +/* + * Used to free events which have a known refcount of 1, such as in error paths + * where the event isn't exposed yet and inherited events. + */ +static void free_event(struct perf_event *event) +{ + if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1, + "unexpected event refcount: %ld; ptr=%p\n", + atomic_long_read(&event->refcount), event)) { + /* leak to avoid use-after-free */ + return; + } + + _free_event(event); +} + +/* + * Remove user event from the owner task. + */ +static void perf_remove_from_owner(struct perf_event *event) +{ + struct task_struct *owner; + + rcu_read_lock(); + /* + * Matches the smp_store_release() 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. + */ + owner = READ_ONCE(event->owner); + 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) { + /* + * If we're here through perf_event_exit_task() we're already + * holding ctx->mutex which would be an inversion wrt. the + * normal lock order. + * + * However we can safely take this lock because its the child + * ctx->mutex. + */ + mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING); + + /* + * 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); + smp_store_release(&event->owner, NULL); + } + mutex_unlock(&owner->perf_event_mutex); + put_task_struct(owner); + } +} + +static void put_event(struct perf_event *event) +{ + if (!atomic_long_dec_and_test(&event->refcount)) + return; + + _free_event(event); +} + +/* + * Kill an event dead; while event:refcount will preserve the event + * object, it will not preserve its functionality. Once the last 'user' + * gives up the object, we'll destroy the thing. + */ +int perf_event_release_kernel(struct perf_event *event) +{ + struct perf_event_context *ctx = event->ctx; + struct perf_event *child, *tmp; + LIST_HEAD(free_list); + + /* + * If we got here through err_file: fput(event_file); we will not have + * attached to a context yet. + */ + if (!ctx) { + WARN_ON_ONCE(event->attach_state & + (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP)); + goto no_ctx; + } + + if (!is_kernel_event(event)) + perf_remove_from_owner(event); + + ctx = perf_event_ctx_lock(event); + WARN_ON_ONCE(ctx->parent_ctx); + + /* + * Mark this event as STATE_DEAD, there is no external reference to it + * anymore. + * + * Anybody acquiring event->child_mutex after the below loop _must_ + * also see this, most importantly inherit_event() which will avoid + * placing more children on the list. + * + * Thus this guarantees that we will in fact observe and kill _ALL_ + * child events. + */ + perf_remove_from_context(event, DETACH_GROUP|DETACH_DEAD); + + perf_event_ctx_unlock(event, ctx); + +again: + mutex_lock(&event->child_mutex); + list_for_each_entry(child, &event->child_list, child_list) { + + /* + * Cannot change, child events are not migrated, see the + * comment with perf_event_ctx_lock_nested(). + */ + ctx = READ_ONCE(child->ctx); + /* + * Since child_mutex nests inside ctx::mutex, we must jump + * through hoops. We start by grabbing a reference on the ctx. + * + * Since the event cannot get freed while we hold the + * child_mutex, the context must also exist and have a !0 + * reference count. + */ + get_ctx(ctx); + + /* + * Now that we have a ctx ref, we can drop child_mutex, and + * acquire ctx::mutex without fear of it going away. Then we + * can re-acquire child_mutex. + */ + mutex_unlock(&event->child_mutex); + mutex_lock(&ctx->mutex); + mutex_lock(&event->child_mutex); + + /* + * Now that we hold ctx::mutex and child_mutex, revalidate our + * state, if child is still the first entry, it didn't get freed + * and we can continue doing so. + */ + tmp = list_first_entry_or_null(&event->child_list, + struct perf_event, child_list); + if (tmp == child) { + perf_remove_from_context(child, DETACH_GROUP); + list_move(&child->child_list, &free_list); + /* + * This matches the refcount bump in inherit_event(); + * this can't be the last reference. + */ + put_event(event); + } + + mutex_unlock(&event->child_mutex); + mutex_unlock(&ctx->mutex); + put_ctx(ctx); + goto again; + } + mutex_unlock(&event->child_mutex); + + list_for_each_entry_safe(child, tmp, &free_list, child_list) { + void *var = &child->ctx->refcount; + + list_del(&child->child_list); + free_event(child); + + /* + * Wake any perf_event_free_task() waiting for this event to be + * freed. + */ + smp_mb(); /* pairs with wait_var_event() */ + wake_up_var(var); + } + +no_ctx: + put_event(event); /* Must be the 'last' reference */ + 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) +{ + perf_event_release_kernel(file->private_data); + return 0; +} + +static 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); + + (void)perf_event_read(event, false); + total += perf_event_count(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) { + (void)perf_event_read(child, false); + total += perf_event_count(child); + *enabled += child->total_time_enabled; + *running += child->total_time_running; + } + mutex_unlock(&event->child_mutex); + + return total; +} + +u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running) +{ + struct perf_event_context *ctx; + u64 count; + + ctx = perf_event_ctx_lock(event); + count = __perf_event_read_value(event, enabled, running); + perf_event_ctx_unlock(event, ctx); + + return count; +} +EXPORT_SYMBOL_GPL(perf_event_read_value); + +static int __perf_read_group_add(struct perf_event *leader, + u64 read_format, u64 *values) +{ + struct perf_event_context *ctx = leader->ctx; + struct perf_event *sub, *parent; + unsigned long flags; + int n = 1; /* skip @nr */ + int ret; + + ret = perf_event_read(leader, true); + if (ret) + return ret; + + raw_spin_lock_irqsave(&ctx->lock, flags); + /* + * Verify the grouping between the parent and child (inherited) + * events is still in tact. + * + * Specifically: + * - leader->ctx->lock pins leader->sibling_list + * - parent->child_mutex pins parent->child_list + * - parent->ctx->mutex pins parent->sibling_list + * + * Because parent->ctx != leader->ctx (and child_list nests inside + * ctx->mutex), group destruction is not atomic between children, also + * see perf_event_release_kernel(). Additionally, parent can grow the + * group. + * + * Therefore it is possible to have parent and child groups in a + * different configuration and summing over such a beast makes no sense + * what so ever. + * + * Reject this. + */ + parent = leader->parent; + if (parent && + (parent->group_generation != leader->group_generation || + parent->nr_siblings != leader->nr_siblings)) { + ret = -ECHILD; + goto unlock; + } + + /* + * Since we co-schedule groups, {enabled,running} times of siblings + * will be identical to those of the leader, so we only publish one + * set. + */ + if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) { + values[n++] += leader->total_time_enabled + + atomic64_read(&leader->child_total_time_enabled); + } + + if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) { + values[n++] += leader->total_time_running + + atomic64_read(&leader->child_total_time_running); + } + + /* + * Write {count,id} tuples for every sibling. + */ + values[n++] += perf_event_count(leader); + if (read_format & PERF_FORMAT_ID) + values[n++] = primary_event_id(leader); + if (read_format & PERF_FORMAT_LOST) + values[n++] = atomic64_read(&leader->lost_samples); + + for_each_sibling_event(sub, leader) { + values[n++] += perf_event_count(sub); + if (read_format & PERF_FORMAT_ID) + values[n++] = primary_event_id(sub); + if (read_format & PERF_FORMAT_LOST) + values[n++] = atomic64_read(&sub->lost_samples); + } + +unlock: + raw_spin_unlock_irqrestore(&ctx->lock, flags); + return ret; +} + +static int perf_read_group(struct perf_event *event, + u64 read_format, char __user *buf) +{ + struct perf_event *leader = event->group_leader, *child; + struct perf_event_context *ctx = leader->ctx; + int ret; + u64 *values; + + lockdep_assert_held(&ctx->mutex); + + values = kzalloc(event->read_size, GFP_KERNEL); + if (!values) + return -ENOMEM; + + values[0] = 1 + leader->nr_siblings; + + mutex_lock(&leader->child_mutex); + + ret = __perf_read_group_add(leader, read_format, values); + if (ret) + goto unlock; + + list_for_each_entry(child, &leader->child_list, child_list) { + ret = __perf_read_group_add(child, read_format, values); + if (ret) + goto unlock; + } + + mutex_unlock(&leader->child_mutex); + + ret = event->read_size; + if (copy_to_user(buf, values, event->read_size)) + ret = -EFAULT; + goto out; + +unlock: + mutex_unlock(&leader->child_mutex); +out: + kfree(values); + return ret; +} + +static int perf_read_one(struct perf_event *event, + u64 read_format, char __user *buf) +{ + u64 enabled, running; + u64 values[5]; + 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 (read_format & PERF_FORMAT_LOST) + values[n++] = atomic64_read(&event->lost_samples); + + if (copy_to_user(buf, values, n * sizeof(u64))) + return -EFAULT; + + return n * sizeof(u64); +} + +static bool is_event_hup(struct perf_event *event) +{ + bool no_children; + + if (event->state > PERF_EVENT_STATE_EXIT) + return false; + + mutex_lock(&event->child_mutex); + no_children = list_empty(&event->child_list); + mutex_unlock(&event->child_mutex); + return no_children; +} + +/* + * Read the performance event - simple non blocking version for now + */ +static ssize_t +__perf_read(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 an 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_read_group(event, read_format, buf); + else + ret = perf_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; + struct perf_event_context *ctx; + int ret; + + ret = security_perf_event_read(event); + if (ret) + return ret; + + ctx = perf_event_ctx_lock(event); + ret = __perf_read(event, buf, count); + perf_event_ctx_unlock(event, ctx); + + return ret; +} + +static __poll_t perf_poll(struct file *file, poll_table *wait) +{ + struct perf_event *event = file->private_data; + struct perf_buffer *rb; + __poll_t events = EPOLLHUP; + + poll_wait(file, &event->waitq, wait); + + if (is_event_hup(event)) + return events; + + /* + * Pin the event->rb by taking event->mmap_mutex; otherwise + * perf_event_set_output() can swizzle our rb and make us miss wakeups. + */ + mutex_lock(&event->mmap_mutex); + rb = event->rb; + if (rb) + events = atomic_xchg(&rb->poll, 0); + mutex_unlock(&event->mmap_mutex); + return events; +} + +static void _perf_event_reset(struct perf_event *event) +{ + (void)perf_event_read(event, false); + local64_set(&event->count, 0); + perf_event_update_userpage(event); +} + +/* Assume it's not an event with inherit set. */ +u64 perf_event_pause(struct perf_event *event, bool reset) +{ + struct perf_event_context *ctx; + u64 count; + + ctx = perf_event_ctx_lock(event); + WARN_ON_ONCE(event->attr.inherit); + _perf_event_disable(event); + count = local64_read(&event->count); + if (reset) + local64_set(&event->count, 0); + perf_event_ctx_unlock(event, ctx); + + return count; +} +EXPORT_SYMBOL_GPL(perf_event_pause); + +/* + * Holding the top-level event's child_mutex means that any + * descendant process that has inherited this event will block + * in perf_event_exit_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; + + lockdep_assert_held(&ctx->mutex); + + event = event->group_leader; + + perf_event_for_each_child(event, func); + for_each_sibling_event(sibling, event) + perf_event_for_each_child(sibling, func); +} + +static void __perf_event_period(struct perf_event *event, + struct perf_cpu_context *cpuctx, + struct perf_event_context *ctx, + void *info) +{ + u64 value = *((u64 *)info); + bool active; + + if (event->attr.freq) { + event->attr.sample_freq = value; + } else { + event->attr.sample_period = value; + event->hw.sample_period = value; + } + + active = (event->state == PERF_EVENT_STATE_ACTIVE); + if (active) { + perf_pmu_disable(ctx->pmu); + /* + * We could be throttled; unthrottle now to avoid the tick + * trying to unthrottle while we already re-started the event. + */ + if (event->hw.interrupts == MAX_INTERRUPTS) { + event->hw.interrupts = 0; + perf_log_throttle(event, 1); + } + event->pmu->stop(event, PERF_EF_UPDATE); + } + + local64_set(&event->hw.period_left, 0); + + if (active) { + event->pmu->start(event, PERF_EF_RELOAD); + perf_pmu_enable(ctx->pmu); + } +} + +static int perf_event_check_period(struct perf_event *event, u64 value) +{ + return event->pmu->check_period(event, value); +} + +static int _perf_event_period(struct perf_event *event, u64 value) +{ + if (!is_sampling_event(event)) + return -EINVAL; + + if (!value) + return -EINVAL; + + if (event->attr.freq && value > sysctl_perf_event_sample_rate) + return -EINVAL; + + if (perf_event_check_period(event, value)) + return -EINVAL; + + if (!event->attr.freq && (value & (1ULL << 63))) + return -EINVAL; + + event_function_call(event, __perf_event_period, &value); + + return 0; +} + +int perf_event_period(struct perf_event *event, u64 value) +{ + struct perf_event_context *ctx; + int ret; + + ctx = perf_event_ctx_lock(event); + ret = _perf_event_period(event, value); + perf_event_ctx_unlock(event, ctx); + + return ret; +} +EXPORT_SYMBOL_GPL(perf_event_period); + +static const struct file_operations perf_fops; + +static inline int perf_fget_light(int fd, struct fd *p) +{ + struct fd f = fdget(fd); + if (!f.file) + return -EBADF; + + if (f.file->f_op != &perf_fops) { + fdput(f); + return -EBADF; + } + *p = f; + return 0; +} + +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 int perf_copy_attr(struct perf_event_attr __user *uattr, + struct perf_event_attr *attr); + +static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg) +{ + 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: + { + u64 value; + + if (copy_from_user(&value, (u64 __user *)arg, sizeof(value))) + return -EFAULT; + + return _perf_event_period(event, value); + } + case PERF_EVENT_IOC_ID: + { + u64 id = primary_event_id(event); + + if (copy_to_user((void __user *)arg, &id, sizeof(id))) + return -EFAULT; + return 0; + } + + case PERF_EVENT_IOC_SET_OUTPUT: + { + int ret; + if (arg != -1) { + struct perf_event *output_event; + struct fd output; + ret = perf_fget_light(arg, &output); + if (ret) + return ret; + output_event = output.file->private_data; + ret = perf_event_set_output(event, output_event); + fdput(output); + } else { + ret = perf_event_set_output(event, NULL); + } + return ret; + } + + case PERF_EVENT_IOC_SET_FILTER: + return perf_event_set_filter(event, (void __user *)arg); + + case PERF_EVENT_IOC_SET_BPF: + { + struct bpf_prog *prog; + int err; + + prog = bpf_prog_get(arg); + if (IS_ERR(prog)) + return PTR_ERR(prog); + + err = perf_event_set_bpf_prog(event, prog, 0); + if (err) { + bpf_prog_put(prog); + return err; + } + + return 0; + } + + case PERF_EVENT_IOC_PAUSE_OUTPUT: { + struct perf_buffer *rb; + + rcu_read_lock(); + rb = rcu_dereference(event->rb); + if (!rb || !rb->nr_pages) { + rcu_read_unlock(); + return -EINVAL; + } + rb_toggle_paused(rb, !!arg); + rcu_read_unlock(); + return 0; + } + + case PERF_EVENT_IOC_QUERY_BPF: + return perf_event_query_prog_array(event, (void __user *)arg); + + case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: { + struct perf_event_attr new_attr; + int err = perf_copy_attr((struct perf_event_attr __user *)arg, + &new_attr); + + if (err) + return err; + + return perf_event_modify_attr(event, &new_attr); + } + 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; +} + +static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg) +{ + struct perf_event *event = file->private_data; + struct perf_event_context *ctx; + long ret; + + /* Treat ioctl like writes as it is likely a mutating operation. */ + ret = security_perf_event_write(event); + if (ret) + return ret; + + ctx = perf_event_ctx_lock(event); + ret = _perf_ioctl(event, cmd, arg); + perf_event_ctx_unlock(event, ctx); + + return ret; +} + +#ifdef CONFIG_COMPAT +static long perf_compat_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + switch (_IOC_NR(cmd)) { + case _IOC_NR(PERF_EVENT_IOC_SET_FILTER): + case _IOC_NR(PERF_EVENT_IOC_ID): + case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF): + case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES): + /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */ + if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) { + cmd &= ~IOCSIZE_MASK; + cmd |= sizeof(void *) << IOCSIZE_SHIFT; + } + break; + } + return perf_ioctl(file, cmd, arg); +} +#else +# define perf_compat_ioctl NULL +#endif + +int perf_event_task_enable(void) +{ + struct perf_event_context *ctx; + struct perf_event *event; + + mutex_lock(¤t->perf_event_mutex); + list_for_each_entry(event, ¤t->perf_event_list, owner_entry) { + ctx = perf_event_ctx_lock(event); + perf_event_for_each_child(event, _perf_event_enable); + perf_event_ctx_unlock(event, ctx); + } + mutex_unlock(¤t->perf_event_mutex); + + return 0; +} + +int perf_event_task_disable(void) +{ + struct perf_event_context *ctx; + struct perf_event *event; + + mutex_lock(¤t->perf_event_mutex); + list_for_each_entry(event, ¤t->perf_event_list, owner_entry) { + ctx = perf_event_ctx_lock(event); + perf_event_for_each_child(event, _perf_event_disable); + perf_event_ctx_unlock(event, ctx); + } + mutex_unlock(¤t->perf_event_mutex); + + return 0; +} + +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->pmu->event_idx(event); +} + +static void perf_event_init_userpage(struct perf_event *event) +{ + struct perf_event_mmap_page *userpg; + struct perf_buffer *rb; + + rcu_read_lock(); + rb = rcu_dereference(event->rb); + if (!rb) + goto unlock; + + userpg = rb->user_page; + + /* Allow new userspace to detect that bit 0 is deprecated */ + userpg->cap_bit0_is_deprecated = 1; + userpg->size = offsetof(struct perf_event_mmap_page, __reserved); + userpg->data_offset = PAGE_SIZE; + userpg->data_size = perf_data_size(rb); + +unlock: + rcu_read_unlock(); +} + +void __weak arch_perf_update_userpage( + struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now) +{ +} + +/* + * 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 *rb; + u64 enabled, running, now; + + rcu_read_lock(); + rb = rcu_dereference(event->rb); + if (!rb) + goto unlock; + + /* + * 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 can be called in + * NMI context + */ + calc_timer_values(event, &now, &enabled, &running); + + userpg = rb->user_page; + /* + * Disable preemption to guarantee consistent time stamps are stored to + * the user page. + */ + preempt_disable(); + ++userpg->lock; + barrier(); + userpg->index = perf_event_index(event); + userpg->offset = perf_event_count(event); + if (userpg->index) + userpg->offset -= local64_read(&event->hw.prev_count); + + userpg->time_enabled = enabled + + atomic64_read(&event->child_total_time_enabled); + + userpg->time_running = running + + atomic64_read(&event->child_total_time_running); + + arch_perf_update_userpage(event, userpg, now); + + barrier(); + ++userpg->lock; + preempt_enable(); +unlock: + rcu_read_unlock(); +} +EXPORT_SYMBOL_GPL(perf_event_update_userpage); + +static vm_fault_t perf_mmap_fault(struct vm_fault *vmf) +{ + struct perf_event *event = vmf->vma->vm_file->private_data; + struct perf_buffer *rb; + vm_fault_t ret = VM_FAULT_SIGBUS; + + if (vmf->flags & FAULT_FLAG_MKWRITE) { + if (vmf->pgoff == 0) + ret = 0; + return ret; + } + + rcu_read_lock(); + rb = rcu_dereference(event->rb); + if (!rb) + goto unlock; + + if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE)) + goto unlock; + + vmf->page = perf_mmap_to_page(rb, vmf->pgoff); + if (!vmf->page) + goto unlock; + + get_page(vmf->page); + vmf->page->mapping = vmf->vma->vm_file->f_mapping; + vmf->page->index = vmf->pgoff; + + ret = 0; +unlock: + rcu_read_unlock(); + + return ret; +} + +static void ring_buffer_attach(struct perf_event *event, + struct perf_buffer *rb) +{ + struct perf_buffer *old_rb = NULL; + unsigned long flags; + + WARN_ON_ONCE(event->parent); + + if (event->rb) { + /* + * Should be impossible, we set this when removing + * event->rb_entry and wait/clear when adding event->rb_entry. + */ + WARN_ON_ONCE(event->rcu_pending); + + old_rb = event->rb; + spin_lock_irqsave(&old_rb->event_lock, flags); + list_del_rcu(&event->rb_entry); + spin_unlock_irqrestore(&old_rb->event_lock, flags); + + event->rcu_batches = get_state_synchronize_rcu(); + event->rcu_pending = 1; + } + + if (rb) { + if (event->rcu_pending) { + cond_synchronize_rcu(event->rcu_batches); + event->rcu_pending = 0; + } + + spin_lock_irqsave(&rb->event_lock, flags); + list_add_rcu(&event->rb_entry, &rb->event_list); + spin_unlock_irqrestore(&rb->event_lock, flags); + } + + /* + * Avoid racing with perf_mmap_close(AUX): stop the event + * before swizzling the event::rb pointer; if it's getting + * unmapped, its aux_mmap_count will be 0 and it won't + * restart. See the comment in __perf_pmu_output_stop(). + * + * Data will inevitably be lost when set_output is done in + * mid-air, but then again, whoever does it like this is + * not in for the data anyway. + */ + if (has_aux(event)) + perf_event_stop(event, 0); + + rcu_assign_pointer(event->rb, rb); + + if (old_rb) { + ring_buffer_put(old_rb); + /* + * Since we detached before setting the new rb, so that we + * could attach the new rb, we could have missed a wakeup. + * Provide it now. + */ + wake_up_all(&event->waitq); + } +} + +static void ring_buffer_wakeup(struct perf_event *event) +{ + struct perf_buffer *rb; + + if (event->parent) + event = event->parent; + + rcu_read_lock(); + rb = rcu_dereference(event->rb); + if (rb) { + list_for_each_entry_rcu(event, &rb->event_list, rb_entry) + wake_up_all(&event->waitq); + } + rcu_read_unlock(); +} + +struct perf_buffer *ring_buffer_get(struct perf_event *event) +{ + struct perf_buffer *rb; + + if (event->parent) + event = event->parent; + + rcu_read_lock(); + rb = rcu_dereference(event->rb); + if (rb) { + if (!refcount_inc_not_zero(&rb->refcount)) + rb = NULL; + } + rcu_read_unlock(); + + return rb; +} + +void ring_buffer_put(struct perf_buffer *rb) +{ + if (!refcount_dec_and_test(&rb->refcount)) + return; + + WARN_ON_ONCE(!list_empty(&rb->event_list)); + + call_rcu(&rb->rcu_head, rb_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); + atomic_inc(&event->rb->mmap_count); + + if (vma->vm_pgoff) + atomic_inc(&event->rb->aux_mmap_count); + + if (event->pmu->event_mapped) + event->pmu->event_mapped(event, vma->vm_mm); +} + +static void perf_pmu_output_stop(struct perf_event *event); + +/* + * A buffer can be mmap()ed multiple times; either directly through the same + * event, or through other events by use of perf_event_set_output(). + * + * In order to undo the VM accounting done by perf_mmap() we need to destroy + * the buffer here, where we still have a VM context. This means we need + * to detach all events redirecting to us. + */ +static void perf_mmap_close(struct vm_area_struct *vma) +{ + struct perf_event *event = vma->vm_file->private_data; + struct perf_buffer *rb = ring_buffer_get(event); + struct user_struct *mmap_user = rb->mmap_user; + int mmap_locked = rb->mmap_locked; + unsigned long size = perf_data_size(rb); + bool detach_rest = false; + + if (event->pmu->event_unmapped) + event->pmu->event_unmapped(event, vma->vm_mm); + + /* + * rb->aux_mmap_count will always drop before rb->mmap_count and + * event->mmap_count, so it is ok to use event->mmap_mutex to + * serialize with perf_mmap here. + */ + if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff && + atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) { + /* + * Stop all AUX events that are writing to this buffer, + * so that we can free its AUX pages and corresponding PMU + * data. Note that after rb::aux_mmap_count dropped to zero, + * they won't start any more (see perf_aux_output_begin()). + */ + perf_pmu_output_stop(event); + + /* now it's safe to free the pages */ + atomic_long_sub(rb->aux_nr_pages - rb->aux_mmap_locked, &mmap_user->locked_vm); + atomic64_sub(rb->aux_mmap_locked, &vma->vm_mm->pinned_vm); + + /* this has to be the last one */ + rb_free_aux(rb); + WARN_ON_ONCE(refcount_read(&rb->aux_refcount)); + + mutex_unlock(&event->mmap_mutex); + } + + if (atomic_dec_and_test(&rb->mmap_count)) + detach_rest = true; + + if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) + goto out_put; + + ring_buffer_attach(event, NULL); + mutex_unlock(&event->mmap_mutex); + + /* If there's still other mmap()s of this buffer, we're done. */ + if (!detach_rest) + goto out_put; + + /* + * No other mmap()s, detach from all other events that might redirect + * into the now unreachable buffer. Somewhat complicated by the + * fact that rb::event_lock otherwise nests inside mmap_mutex. + */ +again: + rcu_read_lock(); + list_for_each_entry_rcu(event, &rb->event_list, rb_entry) { + if (!atomic_long_inc_not_zero(&event->refcount)) { + /* + * This event is en-route to free_event() which will + * detach it and remove it from the list. + */ + continue; + } + rcu_read_unlock(); + + mutex_lock(&event->mmap_mutex); + /* + * Check we didn't race with perf_event_set_output() which can + * swizzle the rb from under us while we were waiting to + * acquire mmap_mutex. + * + * If we find a different rb; ignore this event, a next + * iteration will no longer find it on the list. We have to + * still restart the iteration to make sure we're not now + * iterating the wrong list. + */ + if (event->rb == rb) + ring_buffer_attach(event, NULL); + + mutex_unlock(&event->mmap_mutex); + put_event(event); + + /* + * Restart the iteration; either we're on the wrong list or + * destroyed its integrity by doing a deletion. + */ + goto again; + } + rcu_read_unlock(); + + /* + * It could be there's still a few 0-ref events on the list; they'll + * get cleaned up by free_event() -- they'll also still have their + * ref on the rb and will free it whenever they are done with it. + * + * Aside from that, this buffer is 'fully' detached and unmapped, + * undo the VM accounting. + */ + + atomic_long_sub((size >> PAGE_SHIFT) + 1 - mmap_locked, + &mmap_user->locked_vm); + atomic64_sub(mmap_locked, &vma->vm_mm->pinned_vm); + free_uid(mmap_user); + +out_put: + ring_buffer_put(rb); /* could be last */ +} + +static const struct vm_operations_struct perf_mmap_vmops = { + .open = perf_mmap_open, + .close = perf_mmap_close, /* non mergeable */ + .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(); + struct perf_buffer *rb = NULL; + unsigned long locked, lock_limit; + unsigned long vma_size; + unsigned long nr_pages; + long user_extra = 0, extra = 0; + 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 rb. + */ + if (event->cpu == -1 && event->attr.inherit) + return -EINVAL; + + if (!(vma->vm_flags & VM_SHARED)) + return -EINVAL; + + ret = security_perf_event_read(event); + if (ret) + return ret; + + vma_size = vma->vm_end - vma->vm_start; + + if (vma->vm_pgoff == 0) { + nr_pages = (vma_size / PAGE_SIZE) - 1; + } else { + /* + * AUX area mapping: if rb->aux_nr_pages != 0, it's already + * mapped, all subsequent mappings should have the same size + * and offset. Must be above the normal perf buffer. + */ + u64 aux_offset, aux_size; + + if (!event->rb) + return -EINVAL; + + nr_pages = vma_size / PAGE_SIZE; + + mutex_lock(&event->mmap_mutex); + ret = -EINVAL; + + rb = event->rb; + if (!rb) + goto aux_unlock; + + aux_offset = READ_ONCE(rb->user_page->aux_offset); + aux_size = READ_ONCE(rb->user_page->aux_size); + + if (aux_offset < perf_data_size(rb) + PAGE_SIZE) + goto aux_unlock; + + if (aux_offset != vma->vm_pgoff << PAGE_SHIFT) + goto aux_unlock; + + /* already mapped with a different offset */ + if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff) + goto aux_unlock; + + if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE) + goto aux_unlock; + + /* already mapped with a different size */ + if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages) + goto aux_unlock; + + if (!is_power_of_2(nr_pages)) + goto aux_unlock; + + if (!atomic_inc_not_zero(&rb->mmap_count)) + goto aux_unlock; + + if (rb_has_aux(rb)) { + atomic_inc(&rb->aux_mmap_count); + ret = 0; + goto unlock; + } + + atomic_set(&rb->aux_mmap_count, 1); + user_extra = nr_pages; + + goto accounting; + } + + /* + * If we have rb 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; + + WARN_ON_ONCE(event->ctx->parent_ctx); +again: + mutex_lock(&event->mmap_mutex); + if (event->rb) { + if (data_page_nr(event->rb) != nr_pages) { + ret = -EINVAL; + goto unlock; + } + + if (!atomic_inc_not_zero(&event->rb->mmap_count)) { + /* + * Raced against perf_mmap_close(); remove the + * event and try again. + */ + ring_buffer_attach(event, NULL); + mutex_unlock(&event->mmap_mutex); + goto again; + } + + goto unlock; + } + + user_extra = nr_pages + 1; + +accounting: + 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); + + /* + * sysctl_perf_event_mlock may have changed, so that + * user->locked_vm > user_lock_limit + */ + if (user_locked > user_lock_limit) + user_locked = user_lock_limit; + user_locked += user_extra; + + if (user_locked > user_lock_limit) { + /* + * charge locked_vm until it hits user_lock_limit; + * charge the rest from pinned_vm + */ + extra = user_locked - user_lock_limit; + user_extra -= extra; + } + + lock_limit = rlimit(RLIMIT_MEMLOCK); + lock_limit >>= PAGE_SHIFT; + locked = atomic64_read(&vma->vm_mm->pinned_vm) + extra; + + if ((locked > lock_limit) && perf_is_paranoid() && + !capable(CAP_IPC_LOCK)) { + ret = -EPERM; + goto unlock; + } + + WARN_ON(!rb && event->rb); + + if (vma->vm_flags & VM_WRITE) + flags |= RING_BUFFER_WRITABLE; + + if (!rb) { + rb = rb_alloc(nr_pages, + event->attr.watermark ? event->attr.wakeup_watermark : 0, + event->cpu, flags); + + if (!rb) { + ret = -ENOMEM; + goto unlock; + } + + atomic_set(&rb->mmap_count, 1); + rb->mmap_user = get_current_user(); + rb->mmap_locked = extra; + + ring_buffer_attach(event, rb); + + perf_event_update_time(event); + perf_event_init_userpage(event); + perf_event_update_userpage(event); + } else { + ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages, + event->attr.aux_watermark, flags); + if (!ret) + rb->aux_mmap_locked = extra; + } + +unlock: + if (!ret) { + atomic_long_add(user_extra, &user->locked_vm); + atomic64_add(extra, &vma->vm_mm->pinned_vm); + + atomic_inc(&event->mmap_count); + } else if (rb) { + atomic_dec(&rb->mmap_count); + } +aux_unlock: + mutex_unlock(&event->mmap_mutex); + + /* + * Since pinned accounting is per vm we cannot allow fork() to copy our + * vma. + */ + vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP; + vma->vm_ops = &perf_mmap_vmops; + + if (event->pmu->event_mapped) + event->pmu->event_mapped(event, vma->vm_mm); + + return ret; +} + +static int perf_fasync(int fd, struct file *filp, int on) +{ + struct inode *inode = file_inode(filp); + struct perf_event *event = filp->private_data; + int retval; + + inode_lock(inode); + retval = fasync_helper(fd, filp, on, &event->fasync); + inode_unlock(inode); + + 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_compat_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. + */ + +static inline struct fasync_struct **perf_event_fasync(struct perf_event *event) +{ + /* only the parent has fasync state */ + if (event->parent) + event = event->parent; + return &event->fasync; +} + +void perf_event_wakeup(struct perf_event *event) +{ + ring_buffer_wakeup(event); + + if (event->pending_kill) { + kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill); + event->pending_kill = 0; + } +} + +static void perf_sigtrap(struct perf_event *event) +{ + /* + * We'd expect this to only occur if the irq_work is delayed and either + * ctx->task or current has changed in the meantime. This can be the + * case on architectures that do not implement arch_irq_work_raise(). + */ + if (WARN_ON_ONCE(event->ctx->task != current)) + return; + + /* + * Both perf_pending_task() and perf_pending_irq() can race with the + * task exiting. + */ + if (current->flags & PF_EXITING) + return; + + send_sig_perf((void __user *)event->pending_addr, + event->attr.type, event->attr.sig_data); +} + +/* + * Deliver the pending work in-event-context or follow the context. + */ +static void __perf_pending_irq(struct perf_event *event) +{ + int cpu = READ_ONCE(event->oncpu); + + /* + * If the event isn't running; we done. event_sched_out() will have + * taken care of things. + */ + if (cpu < 0) + return; + + /* + * Yay, we hit home and are in the context of the event. + */ + if (cpu == smp_processor_id()) { + if (event->pending_sigtrap) { + event->pending_sigtrap = 0; + perf_sigtrap(event); + local_dec(&event->ctx->nr_pending); + } + if (event->pending_disable) { + event->pending_disable = 0; + perf_event_disable_local(event); + } + return; + } + + /* + * CPU-A CPU-B + * + * perf_event_disable_inatomic() + * @pending_disable = CPU-A; + * irq_work_queue(); + * + * sched-out + * @pending_disable = -1; + * + * sched-in + * perf_event_disable_inatomic() + * @pending_disable = CPU-B; + * irq_work_queue(); // FAILS + * + * irq_work_run() + * perf_pending_irq() + * + * But the event runs on CPU-B and wants disabling there. + */ + irq_work_queue_on(&event->pending_irq, cpu); +} + +static void perf_pending_irq(struct irq_work *entry) +{ + struct perf_event *event = container_of(entry, struct perf_event, pending_irq); + int rctx; + + /* + * If we 'fail' here, that's OK, it means recursion is already disabled + * and we won't recurse 'further'. + */ + rctx = perf_swevent_get_recursion_context(); + + /* + * The wakeup isn't bound to the context of the event -- it can happen + * irrespective of where the event is. + */ + if (event->pending_wakeup) { + event->pending_wakeup = 0; + perf_event_wakeup(event); + } + + __perf_pending_irq(event); + + if (rctx >= 0) + perf_swevent_put_recursion_context(rctx); +} + +static void perf_pending_task(struct callback_head *head) +{ + struct perf_event *event = container_of(head, struct perf_event, pending_task); + int rctx; + + /* + * If we 'fail' here, that's OK, it means recursion is already disabled + * and we won't recurse 'further'. + */ + preempt_disable_notrace(); + rctx = perf_swevent_get_recursion_context(); + + if (event->pending_work) { + event->pending_work = 0; + perf_sigtrap(event); + local_dec(&event->ctx->nr_pending); + } + + if (rctx >= 0) + perf_swevent_put_recursion_context(rctx); + preempt_enable_notrace(); + + put_event(event); +} + +#ifdef CONFIG_GUEST_PERF_EVENTS +struct perf_guest_info_callbacks __rcu *perf_guest_cbs; + +DEFINE_STATIC_CALL_RET0(__perf_guest_state, *perf_guest_cbs->state); +DEFINE_STATIC_CALL_RET0(__perf_guest_get_ip, *perf_guest_cbs->get_ip); +DEFINE_STATIC_CALL_RET0(__perf_guest_handle_intel_pt_intr, *perf_guest_cbs->handle_intel_pt_intr); + +void perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs) +{ + if (WARN_ON_ONCE(rcu_access_pointer(perf_guest_cbs))) + return; + + rcu_assign_pointer(perf_guest_cbs, cbs); + static_call_update(__perf_guest_state, cbs->state); + static_call_update(__perf_guest_get_ip, cbs->get_ip); + + /* Implementing ->handle_intel_pt_intr is optional. */ + if (cbs->handle_intel_pt_intr) + static_call_update(__perf_guest_handle_intel_pt_intr, + cbs->handle_intel_pt_intr); +} +EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks); + +void perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs) +{ + if (WARN_ON_ONCE(rcu_access_pointer(perf_guest_cbs) != cbs)) + return; + + rcu_assign_pointer(perf_guest_cbs, NULL); + static_call_update(__perf_guest_state, (void *)&__static_call_return0); + static_call_update(__perf_guest_get_ip, (void *)&__static_call_return0); + static_call_update(__perf_guest_handle_intel_pt_intr, + (void *)&__static_call_return0); + synchronize_rcu(); +} +EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks); +#endif + +static void +perf_output_sample_regs(struct perf_output_handle *handle, + struct pt_regs *regs, u64 mask) +{ + int bit; + DECLARE_BITMAP(_mask, 64); + + bitmap_from_u64(_mask, mask); + for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) { + u64 val; + + val = perf_reg_value(regs, bit); + perf_output_put(handle, val); + } +} + +static void perf_sample_regs_user(struct perf_regs *regs_user, + struct pt_regs *regs) +{ + if (user_mode(regs)) { + regs_user->abi = perf_reg_abi(current); + regs_user->regs = regs; + } else if (!(current->flags & PF_KTHREAD)) { + perf_get_regs_user(regs_user, regs); + } else { + regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE; + regs_user->regs = NULL; + } +} + +static void perf_sample_regs_intr(struct perf_regs *regs_intr, + struct pt_regs *regs) +{ + regs_intr->regs = regs; + regs_intr->abi = perf_reg_abi(current); +} + + +/* + * Get remaining task size from user stack pointer. + * + * It'd be better to take stack vma map and limit this more + * precisely, but there's no way to get it safely under interrupt, + * so using TASK_SIZE as limit. + */ +static u64 perf_ustack_task_size(struct pt_regs *regs) +{ + unsigned long addr = perf_user_stack_pointer(regs); + + if (!addr || addr >= TASK_SIZE) + return 0; + + return TASK_SIZE - addr; +} + +static u16 +perf_sample_ustack_size(u16 stack_size, u16 header_size, + struct pt_regs *regs) +{ + u64 task_size; + + /* No regs, no stack pointer, no dump. */ + if (!regs) + return 0; + + /* + * Check if we fit in with the requested stack size into the: + * - TASK_SIZE + * If we don't, we limit the size to the TASK_SIZE. + * + * - remaining sample size + * If we don't, we customize the stack size to + * fit in to the remaining sample size. + */ + + task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs)); + stack_size = min(stack_size, (u16) task_size); + + /* Current header size plus static size and dynamic size. */ + header_size += 2 * sizeof(u64); + + /* Do we fit in with the current stack dump size? */ + if ((u16) (header_size + stack_size) < header_size) { + /* + * If we overflow the maximum size for the sample, + * we customize the stack dump size to fit in. + */ + stack_size = USHRT_MAX - header_size - sizeof(u64); + stack_size = round_up(stack_size, sizeof(u64)); + } + + return stack_size; +} + +static void +perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size, + struct pt_regs *regs) +{ + /* Case of a kernel thread, nothing to dump */ + if (!regs) { + u64 size = 0; + perf_output_put(handle, size); + } else { + unsigned long sp; + unsigned int rem; + u64 dyn_size; + + /* + * We dump: + * static size + * - the size requested by user or the best one we can fit + * in to the sample max size + * data + * - user stack dump data + * dynamic size + * - the actual dumped size + */ + + /* Static size. */ + perf_output_put(handle, dump_size); + + /* Data. */ + sp = perf_user_stack_pointer(regs); + rem = __output_copy_user(handle, (void *) sp, dump_size); + dyn_size = dump_size - rem; + + perf_output_skip(handle, rem); + + /* Dynamic size. */ + perf_output_put(handle, dyn_size); + } +} + +static unsigned long perf_prepare_sample_aux(struct perf_event *event, + struct perf_sample_data *data, + size_t size) +{ + struct perf_event *sampler = event->aux_event; + struct perf_buffer *rb; + + data->aux_size = 0; + + if (!sampler) + goto out; + + if (WARN_ON_ONCE(READ_ONCE(sampler->state) != PERF_EVENT_STATE_ACTIVE)) + goto out; + + if (WARN_ON_ONCE(READ_ONCE(sampler->oncpu) != smp_processor_id())) + goto out; + + rb = ring_buffer_get(sampler); + if (!rb) + goto out; + + /* + * If this is an NMI hit inside sampling code, don't take + * the sample. See also perf_aux_sample_output(). + */ + if (READ_ONCE(rb->aux_in_sampling)) { + data->aux_size = 0; + } else { + size = min_t(size_t, size, perf_aux_size(rb)); + data->aux_size = ALIGN(size, sizeof(u64)); + } + ring_buffer_put(rb); + +out: + return data->aux_size; +} + +static long perf_pmu_snapshot_aux(struct perf_buffer *rb, + struct perf_event *event, + struct perf_output_handle *handle, + unsigned long size) +{ + unsigned long flags; + long ret; + + /* + * Normal ->start()/->stop() callbacks run in IRQ mode in scheduler + * paths. If we start calling them in NMI context, they may race with + * the IRQ ones, that is, for example, re-starting an event that's just + * been stopped, which is why we're using a separate callback that + * doesn't change the event state. + * + * IRQs need to be disabled to prevent IPIs from racing with us. + */ + local_irq_save(flags); + /* + * Guard against NMI hits inside the critical section; + * see also perf_prepare_sample_aux(). + */ + WRITE_ONCE(rb->aux_in_sampling, 1); + barrier(); + + ret = event->pmu->snapshot_aux(event, handle, size); + + barrier(); + WRITE_ONCE(rb->aux_in_sampling, 0); + local_irq_restore(flags); + + return ret; +} + +static void perf_aux_sample_output(struct perf_event *event, + struct perf_output_handle *handle, + struct perf_sample_data *data) +{ + struct perf_event *sampler = event->aux_event; + struct perf_buffer *rb; + unsigned long pad; + long size; + + if (WARN_ON_ONCE(!sampler || !data->aux_size)) + return; + + rb = ring_buffer_get(sampler); + if (!rb) + return; + + size = perf_pmu_snapshot_aux(rb, sampler, handle, data->aux_size); + + /* + * An error here means that perf_output_copy() failed (returned a + * non-zero surplus that it didn't copy), which in its current + * enlightened implementation is not possible. If that changes, we'd + * like to know. + */ + if (WARN_ON_ONCE(size < 0)) + goto out_put; + + /* + * The pad comes from ALIGN()ing data->aux_size up to u64 in + * perf_prepare_sample_aux(), so should not be more than that. + */ + pad = data->aux_size - size; + if (WARN_ON_ONCE(pad >= sizeof(u64))) + pad = 8; + + if (pad) { + u64 zero = 0; + perf_output_copy(handle, &zero, pad); + } + +out_put: + ring_buffer_put(rb); +} + +static void __perf_event_header__init_id(struct perf_event_header *header, + struct perf_sample_data *data, + struct perf_event *event, + u64 sample_type) +{ + data->type = event->attr.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_event_clock(event); + + if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER)) + 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; + } +} + +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, event->attr.sample_type); +} + +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); + + if (sample_type & PERF_SAMPLE_IDENTIFIER) + perf_output_put(handle, data->id); +} + +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); +} + +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[5]; + 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); + if (read_format & PERF_FORMAT_LOST) + values[n++] = atomic64_read(&event->lost_samples); + + __output_copy(handle, values, n * sizeof(u64)); +} + +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; + unsigned long flags; + u64 values[6]; + int n = 0; + + /* + * Disabling interrupts avoids all counter scheduling + * (context switches, timer based rotation and IPIs). + */ + local_irq_save(flags); + + 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->state == PERF_EVENT_STATE_ACTIVE)) + leader->pmu->read(leader); + + values[n++] = perf_event_count(leader); + if (read_format & PERF_FORMAT_ID) + values[n++] = primary_event_id(leader); + if (read_format & PERF_FORMAT_LOST) + values[n++] = atomic64_read(&leader->lost_samples); + + __output_copy(handle, values, n * sizeof(u64)); + + for_each_sibling_event(sub, leader) { + n = 0; + + if ((sub != event) && + (sub->state == PERF_EVENT_STATE_ACTIVE)) + sub->pmu->read(sub); + + values[n++] = perf_event_count(sub); + if (read_format & PERF_FORMAT_ID) + values[n++] = primary_event_id(sub); + if (read_format & PERF_FORMAT_LOST) + values[n++] = atomic64_read(&sub->lost_samples); + + __output_copy(handle, values, n * sizeof(u64)); + } + + local_irq_restore(flags); +} + +#define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\ + PERF_FORMAT_TOTAL_TIME_RUNNING) + +/* + * XXX PERF_SAMPLE_READ vs inherited events seems difficult. + * + * The problem is that its both hard and excessively expensive to iterate the + * child list, not to mention that its impossible to IPI the children running + * on another CPU, from interrupt/NMI context. + */ +static void perf_output_read(struct perf_output_handle *handle, + struct perf_event *event) +{ + u64 enabled = 0, running = 0, now; + 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) + calc_timer_values(event, &now, &enabled, &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_IDENTIFIER) + perf_output_put(handle, data->id); + + 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) { + int size = 1; + + size += data->callchain->nr; + size *= sizeof(u64); + __output_copy(handle, data->callchain, size); + } + + if (sample_type & PERF_SAMPLE_RAW) { + struct perf_raw_record *raw = data->raw; + + if (raw) { + struct perf_raw_frag *frag = &raw->frag; + + perf_output_put(handle, raw->size); + do { + if (frag->copy) { + __output_custom(handle, frag->copy, + frag->data, frag->size); + } else { + __output_copy(handle, frag->data, + frag->size); + } + if (perf_raw_frag_last(frag)) + break; + frag = frag->next; + } while (1); + if (frag->pad) + __output_skip(handle, NULL, frag->pad); + } else { + struct { + u32 size; + u32 data; + } raw = { + .size = sizeof(u32), + .data = 0, + }; + perf_output_put(handle, raw); + } + } + + if (sample_type & PERF_SAMPLE_BRANCH_STACK) { + if (data->sample_flags & PERF_SAMPLE_BRANCH_STACK) { + size_t size; + + size = data->br_stack->nr + * sizeof(struct perf_branch_entry); + + perf_output_put(handle, data->br_stack->nr); + if (branch_sample_hw_index(event)) + perf_output_put(handle, data->br_stack->hw_idx); + perf_output_copy(handle, data->br_stack->entries, size); + } else { + /* + * we always store at least the value of nr + */ + u64 nr = 0; + perf_output_put(handle, nr); + } + } + + if (sample_type & PERF_SAMPLE_REGS_USER) { + u64 abi = data->regs_user.abi; + + /* + * If there are no regs to dump, notice it through + * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE). + */ + perf_output_put(handle, abi); + + if (abi) { + u64 mask = event->attr.sample_regs_user; + perf_output_sample_regs(handle, + data->regs_user.regs, + mask); + } + } + + if (sample_type & PERF_SAMPLE_STACK_USER) { + perf_output_sample_ustack(handle, + data->stack_user_size, + data->regs_user.regs); + } + + if (sample_type & PERF_SAMPLE_WEIGHT_TYPE) + perf_output_put(handle, data->weight.full); + + if (sample_type & PERF_SAMPLE_DATA_SRC) + perf_output_put(handle, data->data_src.val); + + if (sample_type & PERF_SAMPLE_TRANSACTION) + perf_output_put(handle, data->txn); + + if (sample_type & PERF_SAMPLE_REGS_INTR) { + u64 abi = data->regs_intr.abi; + /* + * If there are no regs to dump, notice it through + * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE). + */ + perf_output_put(handle, abi); + + if (abi) { + u64 mask = event->attr.sample_regs_intr; + + perf_output_sample_regs(handle, + data->regs_intr.regs, + mask); + } + } + + if (sample_type & PERF_SAMPLE_PHYS_ADDR) + perf_output_put(handle, data->phys_addr); + + if (sample_type & PERF_SAMPLE_CGROUP) + perf_output_put(handle, data->cgroup); + + if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE) + perf_output_put(handle, data->data_page_size); + + if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE) + perf_output_put(handle, data->code_page_size); + + if (sample_type & PERF_SAMPLE_AUX) { + perf_output_put(handle, data->aux_size); + + if (data->aux_size) + perf_aux_sample_output(event, handle, data); + } + + if (!event->attr.watermark) { + int wakeup_events = event->attr.wakeup_events; + + if (wakeup_events) { + struct perf_buffer *rb = handle->rb; + int events = local_inc_return(&rb->events); + + if (events >= wakeup_events) { + local_sub(wakeup_events, &rb->events); + local_inc(&rb->wakeup); + } + } + } +} + +static u64 perf_virt_to_phys(u64 virt) +{ + u64 phys_addr = 0; + + if (!virt) + return 0; + + if (virt >= TASK_SIZE) { + /* If it's vmalloc()d memory, leave phys_addr as 0 */ + if (virt_addr_valid((void *)(uintptr_t)virt) && + !(virt >= VMALLOC_START && virt < VMALLOC_END)) + phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt); + } else { + /* + * Walking the pages tables for user address. + * Interrupts are disabled, so it prevents any tear down + * of the page tables. + * Try IRQ-safe get_user_page_fast_only first. + * If failed, leave phys_addr as 0. + */ + if (current->mm != NULL) { + struct page *p; + + pagefault_disable(); + if (get_user_page_fast_only(virt, 0, &p)) { + phys_addr = page_to_phys(p) + virt % PAGE_SIZE; + put_page(p); + } + pagefault_enable(); + } + } + + return phys_addr; +} + +/* + * Return the pagetable size of a given virtual address. + */ +static u64 perf_get_pgtable_size(struct mm_struct *mm, unsigned long addr) +{ + u64 size = 0; + +#ifdef CONFIG_HAVE_FAST_GUP + pgd_t *pgdp, pgd; + p4d_t *p4dp, p4d; + pud_t *pudp, pud; + pmd_t *pmdp, pmd; + pte_t *ptep, pte; + + pgdp = pgd_offset(mm, addr); + pgd = READ_ONCE(*pgdp); + if (pgd_none(pgd)) + return 0; + + if (pgd_leaf(pgd)) + return pgd_leaf_size(pgd); + + p4dp = p4d_offset_lockless(pgdp, pgd, addr); + p4d = READ_ONCE(*p4dp); + if (!p4d_present(p4d)) + return 0; + + if (p4d_leaf(p4d)) + return p4d_leaf_size(p4d); + + pudp = pud_offset_lockless(p4dp, p4d, addr); + pud = READ_ONCE(*pudp); + if (!pud_present(pud)) + return 0; + + if (pud_leaf(pud)) + return pud_leaf_size(pud); + + pmdp = pmd_offset_lockless(pudp, pud, addr); + pmd = READ_ONCE(*pmdp); + if (!pmd_present(pmd)) + return 0; + + if (pmd_leaf(pmd)) + return pmd_leaf_size(pmd); + + ptep = pte_offset_map(&pmd, addr); + pte = ptep_get_lockless(ptep); + if (pte_present(pte)) + size = pte_leaf_size(pte); + pte_unmap(ptep); +#endif /* CONFIG_HAVE_FAST_GUP */ + + return size; +} + +static u64 perf_get_page_size(unsigned long addr) +{ + struct mm_struct *mm; + unsigned long flags; + u64 size; + + if (!addr) + return 0; + + /* + * Software page-table walkers must disable IRQs, + * which prevents any tear down of the page tables. + */ + local_irq_save(flags); + + mm = current->mm; + if (!mm) { + /* + * For kernel threads and the like, use init_mm so that + * we can find kernel memory. + */ + mm = &init_mm; + } + + size = perf_get_pgtable_size(mm, addr); + + local_irq_restore(flags); + + return size; +} + +static struct perf_callchain_entry __empty_callchain = { .nr = 0, }; + +struct perf_callchain_entry * +perf_callchain(struct perf_event *event, struct pt_regs *regs) +{ + bool kernel = !event->attr.exclude_callchain_kernel; + bool user = !event->attr.exclude_callchain_user; + /* Disallow cross-task user callchains. */ + bool crosstask = event->ctx->task && event->ctx->task != current; + const u32 max_stack = event->attr.sample_max_stack; + struct perf_callchain_entry *callchain; + + if (!kernel && !user) + return &__empty_callchain; + + callchain = get_perf_callchain(regs, 0, kernel, user, + max_stack, crosstask, true); + return callchain ?: &__empty_callchain; +} + +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; + u64 filtered_sample_type; + + header->type = PERF_RECORD_SAMPLE; + header->size = sizeof(*header) + event->header_size; + + header->misc = 0; + header->misc |= perf_misc_flags(regs); + + /* + * Clear the sample flags that have already been done by the + * PMU driver. + */ + filtered_sample_type = sample_type & ~data->sample_flags; + __perf_event_header__init_id(header, data, event, filtered_sample_type); + + if (sample_type & (PERF_SAMPLE_IP | PERF_SAMPLE_CODE_PAGE_SIZE)) + data->ip = perf_instruction_pointer(regs); + + if (sample_type & PERF_SAMPLE_CALLCHAIN) { + int size = 1; + + if (filtered_sample_type & PERF_SAMPLE_CALLCHAIN) + data->callchain = perf_callchain(event, regs); + + size += data->callchain->nr; + + header->size += size * sizeof(u64); + } + + if (sample_type & PERF_SAMPLE_RAW) { + struct perf_raw_record *raw = data->raw; + int size; + + if (raw && (data->sample_flags & PERF_SAMPLE_RAW)) { + struct perf_raw_frag *frag = &raw->frag; + u32 sum = 0; + + do { + sum += frag->size; + if (perf_raw_frag_last(frag)) + break; + frag = frag->next; + } while (1); + + size = round_up(sum + sizeof(u32), sizeof(u64)); + raw->size = size - sizeof(u32); + frag->pad = raw->size - sum; + } else { + size = sizeof(u64); + data->raw = NULL; + } + + header->size += size; + } + + if (sample_type & PERF_SAMPLE_BRANCH_STACK) { + int size = sizeof(u64); /* nr */ + if (data->sample_flags & PERF_SAMPLE_BRANCH_STACK) { + if (branch_sample_hw_index(event)) + size += sizeof(u64); + + size += data->br_stack->nr + * sizeof(struct perf_branch_entry); + } + header->size += size; + } + + if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER)) + perf_sample_regs_user(&data->regs_user, regs); + + if (sample_type & PERF_SAMPLE_REGS_USER) { + /* regs dump ABI info */ + int size = sizeof(u64); + + if (data->regs_user.regs) { + u64 mask = event->attr.sample_regs_user; + size += hweight64(mask) * sizeof(u64); + } + + header->size += size; + } + + if (sample_type & PERF_SAMPLE_STACK_USER) { + /* + * Either we need PERF_SAMPLE_STACK_USER bit to be always + * processed as the last one or have additional check added + * in case new sample type is added, because we could eat + * up the rest of the sample size. + */ + u16 stack_size = event->attr.sample_stack_user; + u16 size = sizeof(u64); + + stack_size = perf_sample_ustack_size(stack_size, header->size, + data->regs_user.regs); + + /* + * If there is something to dump, add space for the dump + * itself and for the field that tells the dynamic size, + * which is how many have been actually dumped. + */ + if (stack_size) + size += sizeof(u64) + stack_size; + + data->stack_user_size = stack_size; + header->size += size; + } + + if (filtered_sample_type & PERF_SAMPLE_WEIGHT_TYPE) + data->weight.full = 0; + + if (filtered_sample_type & PERF_SAMPLE_DATA_SRC) + data->data_src.val = PERF_MEM_NA; + + if (filtered_sample_type & PERF_SAMPLE_TRANSACTION) + data->txn = 0; + + if (sample_type & (PERF_SAMPLE_ADDR | PERF_SAMPLE_PHYS_ADDR | PERF_SAMPLE_DATA_PAGE_SIZE)) { + if (filtered_sample_type & PERF_SAMPLE_ADDR) + data->addr = 0; + } + + if (sample_type & PERF_SAMPLE_REGS_INTR) { + /* regs dump ABI info */ + int size = sizeof(u64); + + perf_sample_regs_intr(&data->regs_intr, regs); + + if (data->regs_intr.regs) { + u64 mask = event->attr.sample_regs_intr; + + size += hweight64(mask) * sizeof(u64); + } + + header->size += size; + } + + if (sample_type & PERF_SAMPLE_PHYS_ADDR && + filtered_sample_type & PERF_SAMPLE_PHYS_ADDR) + data->phys_addr = perf_virt_to_phys(data->addr); + +#ifdef CONFIG_CGROUP_PERF + if (sample_type & PERF_SAMPLE_CGROUP) { + struct cgroup *cgrp; + + /* protected by RCU */ + cgrp = task_css_check(current, perf_event_cgrp_id, 1)->cgroup; + data->cgroup = cgroup_id(cgrp); + } +#endif + + /* + * PERF_DATA_PAGE_SIZE requires PERF_SAMPLE_ADDR. If the user doesn't + * require PERF_SAMPLE_ADDR, kernel implicitly retrieve the data->addr, + * but the value will not dump to the userspace. + */ + if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE) + data->data_page_size = perf_get_page_size(data->addr); + + if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE) + data->code_page_size = perf_get_page_size(data->ip); + + if (sample_type & PERF_SAMPLE_AUX) { + u64 size; + + header->size += sizeof(u64); /* size */ + + /* + * Given the 16bit nature of header::size, an AUX sample can + * easily overflow it, what with all the preceding sample bits. + * Make sure this doesn't happen by using up to U16_MAX bytes + * per sample in total (rounded down to 8 byte boundary). + */ + size = min_t(size_t, U16_MAX - header->size, + event->attr.aux_sample_size); + size = rounddown(size, 8); + size = perf_prepare_sample_aux(event, data, size); + + WARN_ON_ONCE(size + header->size > U16_MAX); + header->size += size; + } + /* + * If you're adding more sample types here, you likely need to do + * something about the overflowing header::size, like repurpose the + * lowest 3 bits of size, which should be always zero at the moment. + * This raises a more important question, do we really need 512k sized + * samples and why, so good argumentation is in order for whatever you + * do here next. + */ + WARN_ON_ONCE(header->size & 7); +} + +static __always_inline int +__perf_event_output(struct perf_event *event, + struct perf_sample_data *data, + struct pt_regs *regs, + int (*output_begin)(struct perf_output_handle *, + struct perf_sample_data *, + struct perf_event *, + unsigned int)) +{ + struct perf_output_handle handle; + struct perf_event_header header; + int err; + + /* protect the callchain buffers */ + rcu_read_lock(); + + perf_prepare_sample(&header, data, event, regs); + + err = output_begin(&handle, data, event, header.size); + if (err) + goto exit; + + perf_output_sample(&handle, &header, data, event); + + perf_output_end(&handle); + +exit: + rcu_read_unlock(); + return err; +} + +void +perf_event_output_forward(struct perf_event *event, + struct perf_sample_data *data, + struct pt_regs *regs) +{ + __perf_event_output(event, data, regs, perf_output_begin_forward); +} + +void +perf_event_output_backward(struct perf_event *event, + struct perf_sample_data *data, + struct pt_regs *regs) +{ + __perf_event_output(event, data, regs, perf_output_begin_backward); +} + +int +perf_event_output(struct perf_event *event, + struct perf_sample_data *data, + struct pt_regs *regs) +{ + return __perf_event_output(event, data, regs, perf_output_begin); +} + +/* + * 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, &sample, event, read_event.header.size); + 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); +} + +typedef void (perf_iterate_f)(struct perf_event *event, void *data); + +static void +perf_iterate_ctx(struct perf_event_context *ctx, + perf_iterate_f output, + void *data, bool all) +{ + struct perf_event *event; + + list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { + if (!all) { + if (event->state < PERF_EVENT_STATE_INACTIVE) + continue; + if (!event_filter_match(event)) + continue; + } + + output(event, data); + } +} + +static void perf_iterate_sb_cpu(perf_iterate_f output, void *data) +{ + struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events); + struct perf_event *event; + + list_for_each_entry_rcu(event, &pel->list, sb_list) { + /* + * Skip events that are not fully formed yet; ensure that + * if we observe event->ctx, both event and ctx will be + * complete enough. See perf_install_in_context(). + */ + if (!smp_load_acquire(&event->ctx)) + continue; + + if (event->state < PERF_EVENT_STATE_INACTIVE) + continue; + if (!event_filter_match(event)) + continue; + output(event, data); + } +} + +/* + * Iterate all events that need to receive side-band events. + * + * For new callers; ensure that account_pmu_sb_event() includes + * your event, otherwise it might not get delivered. + */ +static void +perf_iterate_sb(perf_iterate_f output, void *data, + struct perf_event_context *task_ctx) +{ + struct perf_event_context *ctx; + int ctxn; + + rcu_read_lock(); + preempt_disable(); + + /* + * If we have task_ctx != NULL we only notify the task context itself. + * The task_ctx is set only for EXIT events before releasing task + * context. + */ + if (task_ctx) { + perf_iterate_ctx(task_ctx, output, data, false); + goto done; + } + + perf_iterate_sb_cpu(output, data); + + for_each_task_context_nr(ctxn) { + ctx = rcu_dereference(current->perf_event_ctxp[ctxn]); + if (ctx) + perf_iterate_ctx(ctx, output, data, false); + } +done: + preempt_enable(); + rcu_read_unlock(); +} + +/* + * Clear all file-based filters at exec, they'll have to be + * re-instated when/if these objects are mmapped again. + */ +static void perf_event_addr_filters_exec(struct perf_event *event, void *data) +{ + struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); + struct perf_addr_filter *filter; + unsigned int restart = 0, count = 0; + unsigned long flags; + + if (!has_addr_filter(event)) + return; + + raw_spin_lock_irqsave(&ifh->lock, flags); + list_for_each_entry(filter, &ifh->list, entry) { + if (filter->path.dentry) { + event->addr_filter_ranges[count].start = 0; + event->addr_filter_ranges[count].size = 0; + restart++; + } + + count++; + } + + if (restart) + event->addr_filters_gen++; + raw_spin_unlock_irqrestore(&ifh->lock, flags); + + if (restart) + perf_event_stop(event, 1); +} + +void perf_event_exec(void) +{ + struct perf_event_context *ctx; + int ctxn; + + for_each_task_context_nr(ctxn) { + perf_event_enable_on_exec(ctxn); + perf_event_remove_on_exec(ctxn); + + rcu_read_lock(); + ctx = rcu_dereference(current->perf_event_ctxp[ctxn]); + if (ctx) { + perf_iterate_ctx(ctx, perf_event_addr_filters_exec, + NULL, true); + } + rcu_read_unlock(); + } +} + +struct remote_output { + struct perf_buffer *rb; + int err; +}; + +static void __perf_event_output_stop(struct perf_event *event, void *data) +{ + struct perf_event *parent = event->parent; + struct remote_output *ro = data; + struct perf_buffer *rb = ro->rb; + struct stop_event_data sd = { + .event = event, + }; + + if (!has_aux(event)) + return; + + if (!parent) + parent = event; + + /* + * In case of inheritance, it will be the parent that links to the + * ring-buffer, but it will be the child that's actually using it. + * + * We are using event::rb to determine if the event should be stopped, + * however this may race with ring_buffer_attach() (through set_output), + * which will make us skip the event that actually needs to be stopped. + * So ring_buffer_attach() has to stop an aux event before re-assigning + * its rb pointer. + */ + if (rcu_dereference(parent->rb) == rb) + ro->err = __perf_event_stop(&sd); +} + +static int __perf_pmu_output_stop(void *info) +{ + struct perf_event *event = info; + struct pmu *pmu = event->ctx->pmu; + struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); + struct remote_output ro = { + .rb = event->rb, + }; + + rcu_read_lock(); + perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false); + if (cpuctx->task_ctx) + perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop, + &ro, false); + rcu_read_unlock(); + + return ro.err; +} + +static void perf_pmu_output_stop(struct perf_event *event) +{ + struct perf_event *iter; + int err, cpu; + +restart: + rcu_read_lock(); + list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) { + /* + * For per-CPU events, we need to make sure that neither they + * nor their children are running; for cpu==-1 events it's + * sufficient to stop the event itself if it's active, since + * it can't have children. + */ + cpu = iter->cpu; + if (cpu == -1) + cpu = READ_ONCE(iter->oncpu); + + if (cpu == -1) + continue; + + err = cpu_function_call(cpu, __perf_pmu_output_stop, event); + if (err == -EAGAIN) { + rcu_read_unlock(); + goto restart; + } + } + rcu_read_unlock(); +} + +/* + * task tracking -- fork/exit + * + * enabled by: attr.comm | attr.mmap | attr.mmap2 | 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 int perf_event_task_match(struct perf_event *event) +{ + return event->attr.comm || event->attr.mmap || + event->attr.mmap2 || event->attr.mmap_data || + event->attr.task; +} + +static void perf_event_task_output(struct perf_event *event, + void *data) +{ + struct perf_task_event *task_event = data; + 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; + + if (!perf_event_task_match(event)) + return; + + perf_event_header__init_id(&task_event->event_id.header, &sample, event); + + ret = perf_output_begin(&handle, &sample, event, + task_event->event_id.header.size); + if (ret) + goto out; + + task_event->event_id.pid = perf_event_pid(event, task); + task_event->event_id.tid = perf_event_tid(event, task); + + if (task_event->event_id.header.type == PERF_RECORD_EXIT) { + task_event->event_id.ppid = perf_event_pid(event, + task->real_parent); + task_event->event_id.ptid = perf_event_pid(event, + task->real_parent); + } else { /* PERF_RECORD_FORK */ + task_event->event_id.ppid = perf_event_pid(event, current); + task_event->event_id.ptid = perf_event_tid(event, current); + } + + task_event->event_id.time = perf_event_clock(event); + + 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 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_iterate_sb(perf_event_task_output, + &task_event, + task_ctx); +} + +void perf_event_fork(struct task_struct *task) +{ + perf_event_task(task, NULL, 1); + perf_event_namespaces(task); +} + +/* + * 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 int perf_event_comm_match(struct perf_event *event) +{ + return event->attr.comm; +} + +static void perf_event_comm_output(struct perf_event *event, + void *data) +{ + struct perf_comm_event *comm_event = data; + struct perf_output_handle handle; + struct perf_sample_data sample; + int size = comm_event->event_id.header.size; + int ret; + + if (!perf_event_comm_match(event)) + return; + + perf_event_header__init_id(&comm_event->event_id.header, &sample, event); + ret = perf_output_begin(&handle, &sample, event, + comm_event->event_id.header.size); + + 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); + __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 void perf_event_comm_event(struct perf_comm_event *comm_event) +{ + char comm[TASK_COMM_LEN]; + unsigned int size; + + 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; + + perf_iterate_sb(perf_event_comm_output, + comm_event, + NULL); +} + +void perf_event_comm(struct task_struct *task, bool exec) +{ + struct perf_comm_event comm_event; + + 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 = exec ? PERF_RECORD_MISC_COMM_EXEC : 0, + /* .size */ + }, + /* .pid */ + /* .tid */ + }, + }; + + perf_event_comm_event(&comm_event); +} + +/* + * namespaces tracking + */ + +struct perf_namespaces_event { + struct task_struct *task; + + struct { + struct perf_event_header header; + + u32 pid; + u32 tid; + u64 nr_namespaces; + struct perf_ns_link_info link_info[NR_NAMESPACES]; + } event_id; +}; + +static int perf_event_namespaces_match(struct perf_event *event) +{ + return event->attr.namespaces; +} + +static void perf_event_namespaces_output(struct perf_event *event, + void *data) +{ + struct perf_namespaces_event *namespaces_event = data; + struct perf_output_handle handle; + struct perf_sample_data sample; + u16 header_size = namespaces_event->event_id.header.size; + int ret; + + if (!perf_event_namespaces_match(event)) + return; + + perf_event_header__init_id(&namespaces_event->event_id.header, + &sample, event); + ret = perf_output_begin(&handle, &sample, event, + namespaces_event->event_id.header.size); + if (ret) + goto out; + + namespaces_event->event_id.pid = perf_event_pid(event, + namespaces_event->task); + namespaces_event->event_id.tid = perf_event_tid(event, + namespaces_event->task); + + perf_output_put(&handle, namespaces_event->event_id); + + perf_event__output_id_sample(event, &handle, &sample); + + perf_output_end(&handle); +out: + namespaces_event->event_id.header.size = header_size; +} + +static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info, + struct task_struct *task, + const struct proc_ns_operations *ns_ops) +{ + struct path ns_path; + struct inode *ns_inode; + int error; + + error = ns_get_path(&ns_path, task, ns_ops); + if (!error) { + ns_inode = ns_path.dentry->d_inode; + ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev); + ns_link_info->ino = ns_inode->i_ino; + path_put(&ns_path); + } +} + +void perf_event_namespaces(struct task_struct *task) +{ + struct perf_namespaces_event namespaces_event; + struct perf_ns_link_info *ns_link_info; + + if (!atomic_read(&nr_namespaces_events)) + return; + + namespaces_event = (struct perf_namespaces_event){ + .task = task, + .event_id = { + .header = { + .type = PERF_RECORD_NAMESPACES, + .misc = 0, + .size = sizeof(namespaces_event.event_id), + }, + /* .pid */ + /* .tid */ + .nr_namespaces = NR_NAMESPACES, + /* .link_info[NR_NAMESPACES] */ + }, + }; + + ns_link_info = namespaces_event.event_id.link_info; + + perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX], + task, &mntns_operations); + +#ifdef CONFIG_USER_NS + perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX], + task, &userns_operations); +#endif +#ifdef CONFIG_NET_NS + perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX], + task, &netns_operations); +#endif +#ifdef CONFIG_UTS_NS + perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX], + task, &utsns_operations); +#endif +#ifdef CONFIG_IPC_NS + perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX], + task, &ipcns_operations); +#endif +#ifdef CONFIG_PID_NS + perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX], + task, &pidns_operations); +#endif +#ifdef CONFIG_CGROUPS + perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX], + task, &cgroupns_operations); +#endif + + perf_iterate_sb(perf_event_namespaces_output, + &namespaces_event, + NULL); +} + +/* + * cgroup tracking + */ +#ifdef CONFIG_CGROUP_PERF + +struct perf_cgroup_event { + char *path; + int path_size; + struct { + struct perf_event_header header; + u64 id; + char path[]; + } event_id; +}; + +static int perf_event_cgroup_match(struct perf_event *event) +{ + return event->attr.cgroup; +} + +static void perf_event_cgroup_output(struct perf_event *event, void *data) +{ + struct perf_cgroup_event *cgroup_event = data; + struct perf_output_handle handle; + struct perf_sample_data sample; + u16 header_size = cgroup_event->event_id.header.size; + int ret; + + if (!perf_event_cgroup_match(event)) + return; + + perf_event_header__init_id(&cgroup_event->event_id.header, + &sample, event); + ret = perf_output_begin(&handle, &sample, event, + cgroup_event->event_id.header.size); + if (ret) + goto out; + + perf_output_put(&handle, cgroup_event->event_id); + __output_copy(&handle, cgroup_event->path, cgroup_event->path_size); + + perf_event__output_id_sample(event, &handle, &sample); + + perf_output_end(&handle); +out: + cgroup_event->event_id.header.size = header_size; +} + +static void perf_event_cgroup(struct cgroup *cgrp) +{ + struct perf_cgroup_event cgroup_event; + char path_enomem[16] = "//enomem"; + char *pathname; + size_t size; + + if (!atomic_read(&nr_cgroup_events)) + return; + + cgroup_event = (struct perf_cgroup_event){ + .event_id = { + .header = { + .type = PERF_RECORD_CGROUP, + .misc = 0, + .size = sizeof(cgroup_event.event_id), + }, + .id = cgroup_id(cgrp), + }, + }; + + pathname = kmalloc(PATH_MAX, GFP_KERNEL); + if (pathname == NULL) { + cgroup_event.path = path_enomem; + } else { + /* just to be sure to have enough space for alignment */ + cgroup_path(cgrp, pathname, PATH_MAX - sizeof(u64)); + cgroup_event.path = pathname; + } + + /* + * Since our buffer works in 8 byte units we need to align our string + * size to a multiple of 8. However, we must guarantee the tail end is + * zero'd out to avoid leaking random bits to userspace. + */ + size = strlen(cgroup_event.path) + 1; + while (!IS_ALIGNED(size, sizeof(u64))) + cgroup_event.path[size++] = '\0'; + + cgroup_event.event_id.header.size += size; + cgroup_event.path_size = size; + + perf_iterate_sb(perf_event_cgroup_output, + &cgroup_event, + NULL); + + kfree(pathname); +} + +#endif + +/* + * mmap tracking + */ + +struct perf_mmap_event { + struct vm_area_struct *vma; + + const char *file_name; + int file_size; + int maj, min; + u64 ino; + u64 ino_generation; + u32 prot, flags; + u8 build_id[BUILD_ID_SIZE_MAX]; + u32 build_id_size; + + struct { + struct perf_event_header header; + + u32 pid; + u32 tid; + u64 start; + u64 len; + u64 pgoff; + } event_id; +}; + +static int perf_event_mmap_match(struct perf_event *event, + void *data) +{ + struct perf_mmap_event *mmap_event = data; + struct vm_area_struct *vma = mmap_event->vma; + int executable = vma->vm_flags & VM_EXEC; + + return (!executable && event->attr.mmap_data) || + (executable && (event->attr.mmap || event->attr.mmap2)); +} + +static void perf_event_mmap_output(struct perf_event *event, + void *data) +{ + struct perf_mmap_event *mmap_event = data; + struct perf_output_handle handle; + struct perf_sample_data sample; + int size = mmap_event->event_id.header.size; + u32 type = mmap_event->event_id.header.type; + bool use_build_id; + int ret; + + if (!perf_event_mmap_match(event, data)) + return; + + if (event->attr.mmap2) { + mmap_event->event_id.header.type = PERF_RECORD_MMAP2; + mmap_event->event_id.header.size += sizeof(mmap_event->maj); + mmap_event->event_id.header.size += sizeof(mmap_event->min); + mmap_event->event_id.header.size += sizeof(mmap_event->ino); + mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation); + mmap_event->event_id.header.size += sizeof(mmap_event->prot); + mmap_event->event_id.header.size += sizeof(mmap_event->flags); + } + + perf_event_header__init_id(&mmap_event->event_id.header, &sample, event); + ret = perf_output_begin(&handle, &sample, event, + mmap_event->event_id.header.size); + if (ret) + goto out; + + mmap_event->event_id.pid = perf_event_pid(event, current); + mmap_event->event_id.tid = perf_event_tid(event, current); + + use_build_id = event->attr.build_id && mmap_event->build_id_size; + + if (event->attr.mmap2 && use_build_id) + mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_BUILD_ID; + + perf_output_put(&handle, mmap_event->event_id); + + if (event->attr.mmap2) { + if (use_build_id) { + u8 size[4] = { (u8) mmap_event->build_id_size, 0, 0, 0 }; + + __output_copy(&handle, size, 4); + __output_copy(&handle, mmap_event->build_id, BUILD_ID_SIZE_MAX); + } else { + perf_output_put(&handle, mmap_event->maj); + perf_output_put(&handle, mmap_event->min); + perf_output_put(&handle, mmap_event->ino); + perf_output_put(&handle, mmap_event->ino_generation); + } + perf_output_put(&handle, mmap_event->prot); + perf_output_put(&handle, mmap_event->flags); + } + + __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; + mmap_event->event_id.header.type = type; +} + +static void perf_event_mmap_event(struct perf_mmap_event *mmap_event) +{ + struct vm_area_struct *vma = mmap_event->vma; + struct file *file = vma->vm_file; + int maj = 0, min = 0; + u64 ino = 0, gen = 0; + u32 prot = 0, flags = 0; + unsigned int size; + char tmp[16]; + char *buf = NULL; + char *name; + + if (vma->vm_flags & VM_READ) + prot |= PROT_READ; + if (vma->vm_flags & VM_WRITE) + prot |= PROT_WRITE; + if (vma->vm_flags & VM_EXEC) + prot |= PROT_EXEC; + + if (vma->vm_flags & VM_MAYSHARE) + flags = MAP_SHARED; + else + flags = MAP_PRIVATE; + + if (vma->vm_flags & VM_LOCKED) + flags |= MAP_LOCKED; + if (is_vm_hugetlb_page(vma)) + flags |= MAP_HUGETLB; + + if (file) { + struct inode *inode; + dev_t dev; + + buf = kmalloc(PATH_MAX, GFP_KERNEL); + if (!buf) { + name = "//enomem"; + goto cpy_name; + } + /* + * d_path() works from the end of the rb backwards, so we + * need to add enough zero bytes after the string to handle + * the 64bit alignment we do later. + */ + name = file_path(file, buf, PATH_MAX - sizeof(u64)); + if (IS_ERR(name)) { + name = "//toolong"; + goto cpy_name; + } + inode = file_inode(vma->vm_file); + dev = inode->i_sb->s_dev; + ino = inode->i_ino; + gen = inode->i_generation; + maj = MAJOR(dev); + min = MINOR(dev); + + goto got_name; + } else { + if (vma->vm_ops && vma->vm_ops->name) { + name = (char *) vma->vm_ops->name(vma); + if (name) + goto cpy_name; + } + + name = (char *)arch_vma_name(vma); + if (name) + goto cpy_name; + + if (vma->vm_start <= vma->vm_mm->start_brk && + vma->vm_end >= vma->vm_mm->brk) { + name = "[heap]"; + goto cpy_name; + } + if (vma->vm_start <= vma->vm_mm->start_stack && + vma->vm_end >= vma->vm_mm->start_stack) { + name = "[stack]"; + goto cpy_name; + } + + name = "//anon"; + goto cpy_name; + } + +cpy_name: + strlcpy(tmp, name, sizeof(tmp)); + name = tmp; +got_name: + /* + * Since our buffer works in 8 byte units we need to align our string + * size to a multiple of 8. However, we must guarantee the tail end is + * zero'd out to avoid leaking random bits to userspace. + */ + size = strlen(name)+1; + while (!IS_ALIGNED(size, sizeof(u64))) + name[size++] = '\0'; + + mmap_event->file_name = name; + mmap_event->file_size = size; + mmap_event->maj = maj; + mmap_event->min = min; + mmap_event->ino = ino; + mmap_event->ino_generation = gen; + mmap_event->prot = prot; + mmap_event->flags = flags; + + if (!(vma->vm_flags & VM_EXEC)) + mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA; + + mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size; + + if (atomic_read(&nr_build_id_events)) + build_id_parse(vma, mmap_event->build_id, &mmap_event->build_id_size); + + perf_iterate_sb(perf_event_mmap_output, + mmap_event, + NULL); + + kfree(buf); +} + +/* + * Check whether inode and address range match filter criteria. + */ +static bool perf_addr_filter_match(struct perf_addr_filter *filter, + struct file *file, unsigned long offset, + unsigned long size) +{ + /* d_inode(NULL) won't be equal to any mapped user-space file */ + if (!filter->path.dentry) + return false; + + if (d_inode(filter->path.dentry) != file_inode(file)) + return false; + + if (filter->offset > offset + size) + return false; + + if (filter->offset + filter->size < offset) + return false; + + return true; +} + +static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter, + struct vm_area_struct *vma, + struct perf_addr_filter_range *fr) +{ + unsigned long vma_size = vma->vm_end - vma->vm_start; + unsigned long off = vma->vm_pgoff << PAGE_SHIFT; + struct file *file = vma->vm_file; + + if (!perf_addr_filter_match(filter, file, off, vma_size)) + return false; + + if (filter->offset < off) { + fr->start = vma->vm_start; + fr->size = min(vma_size, filter->size - (off - filter->offset)); + } else { + fr->start = vma->vm_start + filter->offset - off; + fr->size = min(vma->vm_end - fr->start, filter->size); + } + + return true; +} + +static void __perf_addr_filters_adjust(struct perf_event *event, void *data) +{ + struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); + struct vm_area_struct *vma = data; + struct perf_addr_filter *filter; + unsigned int restart = 0, count = 0; + unsigned long flags; + + if (!has_addr_filter(event)) + return; + + if (!vma->vm_file) + return; + + raw_spin_lock_irqsave(&ifh->lock, flags); + list_for_each_entry(filter, &ifh->list, entry) { + if (perf_addr_filter_vma_adjust(filter, vma, + &event->addr_filter_ranges[count])) + restart++; + + count++; + } + + if (restart) + event->addr_filters_gen++; + raw_spin_unlock_irqrestore(&ifh->lock, flags); + + if (restart) + perf_event_stop(event, 1); +} + +/* + * Adjust all task's events' filters to the new vma + */ +static void perf_addr_filters_adjust(struct vm_area_struct *vma) +{ + struct perf_event_context *ctx; + int ctxn; + + /* + * Data tracing isn't supported yet and as such there is no need + * to keep track of anything that isn't related to executable code: + */ + if (!(vma->vm_flags & VM_EXEC)) + return; + + rcu_read_lock(); + for_each_task_context_nr(ctxn) { + ctx = rcu_dereference(current->perf_event_ctxp[ctxn]); + if (!ctx) + continue; + + perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true); + } + rcu_read_unlock(); +} + +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, + }, + /* .maj (attr_mmap2 only) */ + /* .min (attr_mmap2 only) */ + /* .ino (attr_mmap2 only) */ + /* .ino_generation (attr_mmap2 only) */ + /* .prot (attr_mmap2 only) */ + /* .flags (attr_mmap2 only) */ + }; + + perf_addr_filters_adjust(vma); + perf_event_mmap_event(&mmap_event); +} + +void perf_event_aux_event(struct perf_event *event, unsigned long head, + unsigned long size, u64 flags) +{ + struct perf_output_handle handle; + struct perf_sample_data sample; + struct perf_aux_event { + struct perf_event_header header; + u64 offset; + u64 size; + u64 flags; + } rec = { + .header = { + .type = PERF_RECORD_AUX, + .misc = 0, + .size = sizeof(rec), + }, + .offset = head, + .size = size, + .flags = flags, + }; + int ret; + + perf_event_header__init_id(&rec.header, &sample, event); + ret = perf_output_begin(&handle, &sample, event, rec.header.size); + + if (ret) + return; + + perf_output_put(&handle, rec); + perf_event__output_id_sample(event, &handle, &sample); + + perf_output_end(&handle); +} + +/* + * Lost/dropped samples logging + */ +void perf_log_lost_samples(struct perf_event *event, u64 lost) +{ + struct perf_output_handle handle; + struct perf_sample_data sample; + int ret; + + struct { + struct perf_event_header header; + u64 lost; + } lost_samples_event = { + .header = { + .type = PERF_RECORD_LOST_SAMPLES, + .misc = 0, + .size = sizeof(lost_samples_event), + }, + .lost = lost, + }; + + perf_event_header__init_id(&lost_samples_event.header, &sample, event); + + ret = perf_output_begin(&handle, &sample, event, + lost_samples_event.header.size); + if (ret) + return; + + perf_output_put(&handle, lost_samples_event); + perf_event__output_id_sample(event, &handle, &sample); + perf_output_end(&handle); +} + +/* + * context_switch tracking + */ + +struct perf_switch_event { + struct task_struct *task; + struct task_struct *next_prev; + + struct { + struct perf_event_header header; + u32 next_prev_pid; + u32 next_prev_tid; + } event_id; +}; + +static int perf_event_switch_match(struct perf_event *event) +{ + return event->attr.context_switch; +} + +static void perf_event_switch_output(struct perf_event *event, void *data) +{ + struct perf_switch_event *se = data; + struct perf_output_handle handle; + struct perf_sample_data sample; + int ret; + + if (!perf_event_switch_match(event)) + return; + + /* Only CPU-wide events are allowed to see next/prev pid/tid */ + if (event->ctx->task) { + se->event_id.header.type = PERF_RECORD_SWITCH; + se->event_id.header.size = sizeof(se->event_id.header); + } else { + se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE; + se->event_id.header.size = sizeof(se->event_id); + se->event_id.next_prev_pid = + perf_event_pid(event, se->next_prev); + se->event_id.next_prev_tid = + perf_event_tid(event, se->next_prev); + } + + perf_event_header__init_id(&se->event_id.header, &sample, event); + + ret = perf_output_begin(&handle, &sample, event, se->event_id.header.size); + if (ret) + return; + + if (event->ctx->task) + perf_output_put(&handle, se->event_id.header); + else + perf_output_put(&handle, se->event_id); + + perf_event__output_id_sample(event, &handle, &sample); + + perf_output_end(&handle); +} + +static void perf_event_switch(struct task_struct *task, + struct task_struct *next_prev, bool sched_in) +{ + struct perf_switch_event switch_event; + + /* N.B. caller checks nr_switch_events != 0 */ + + switch_event = (struct perf_switch_event){ + .task = task, + .next_prev = next_prev, + .event_id = { + .header = { + /* .type */ + .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT, + /* .size */ + }, + /* .next_prev_pid */ + /* .next_prev_tid */ + }, + }; + + if (!sched_in && task->on_rq) { + switch_event.event_id.header.misc |= + PERF_RECORD_MISC_SWITCH_OUT_PREEMPT; + } + + perf_iterate_sb(perf_event_switch_output, &switch_event, NULL); +} + +/* + * 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_event_clock(event), + .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, &sample, event, + throttle_event.header.size); + if (ret) + return; + + perf_output_put(&handle, throttle_event); + perf_event__output_id_sample(event, &handle, &sample); + perf_output_end(&handle); +} + +/* + * ksymbol register/unregister tracking + */ + +struct perf_ksymbol_event { + const char *name; + int name_len; + struct { + struct perf_event_header header; + u64 addr; + u32 len; + u16 ksym_type; + u16 flags; + } event_id; +}; + +static int perf_event_ksymbol_match(struct perf_event *event) +{ + return event->attr.ksymbol; +} + +static void perf_event_ksymbol_output(struct perf_event *event, void *data) +{ + struct perf_ksymbol_event *ksymbol_event = data; + struct perf_output_handle handle; + struct perf_sample_data sample; + int ret; + + if (!perf_event_ksymbol_match(event)) + return; + + perf_event_header__init_id(&ksymbol_event->event_id.header, + &sample, event); + ret = perf_output_begin(&handle, &sample, event, + ksymbol_event->event_id.header.size); + if (ret) + return; + + perf_output_put(&handle, ksymbol_event->event_id); + __output_copy(&handle, ksymbol_event->name, ksymbol_event->name_len); + perf_event__output_id_sample(event, &handle, &sample); + + perf_output_end(&handle); +} + +void perf_event_ksymbol(u16 ksym_type, u64 addr, u32 len, bool unregister, + const char *sym) +{ + struct perf_ksymbol_event ksymbol_event; + char name[KSYM_NAME_LEN]; + u16 flags = 0; + int name_len; + + if (!atomic_read(&nr_ksymbol_events)) + return; + + if (ksym_type >= PERF_RECORD_KSYMBOL_TYPE_MAX || + ksym_type == PERF_RECORD_KSYMBOL_TYPE_UNKNOWN) + goto err; + + strlcpy(name, sym, KSYM_NAME_LEN); + name_len = strlen(name) + 1; + while (!IS_ALIGNED(name_len, sizeof(u64))) + name[name_len++] = '\0'; + BUILD_BUG_ON(KSYM_NAME_LEN % sizeof(u64)); + + if (unregister) + flags |= PERF_RECORD_KSYMBOL_FLAGS_UNREGISTER; + + ksymbol_event = (struct perf_ksymbol_event){ + .name = name, + .name_len = name_len, + .event_id = { + .header = { + .type = PERF_RECORD_KSYMBOL, + .size = sizeof(ksymbol_event.event_id) + + name_len, + }, + .addr = addr, + .len = len, + .ksym_type = ksym_type, + .flags = flags, + }, + }; + + perf_iterate_sb(perf_event_ksymbol_output, &ksymbol_event, NULL); + return; +err: + WARN_ONCE(1, "%s: Invalid KSYMBOL type 0x%x\n", __func__, ksym_type); +} + +/* + * bpf program load/unload tracking + */ + +struct perf_bpf_event { + struct bpf_prog *prog; + struct { + struct perf_event_header header; + u16 type; + u16 flags; + u32 id; + u8 tag[BPF_TAG_SIZE]; + } event_id; +}; + +static int perf_event_bpf_match(struct perf_event *event) +{ + return event->attr.bpf_event; +} + +static void perf_event_bpf_output(struct perf_event *event, void *data) +{ + struct perf_bpf_event *bpf_event = data; + struct perf_output_handle handle; + struct perf_sample_data sample; + int ret; + + if (!perf_event_bpf_match(event)) + return; + + perf_event_header__init_id(&bpf_event->event_id.header, + &sample, event); + ret = perf_output_begin(&handle, &sample, event, + bpf_event->event_id.header.size); + if (ret) + return; + + perf_output_put(&handle, bpf_event->event_id); + perf_event__output_id_sample(event, &handle, &sample); + + perf_output_end(&handle); +} + +static void perf_event_bpf_emit_ksymbols(struct bpf_prog *prog, + enum perf_bpf_event_type type) +{ + bool unregister = type == PERF_BPF_EVENT_PROG_UNLOAD; + int i; + + if (prog->aux->func_cnt == 0) { + perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF, + (u64)(unsigned long)prog->bpf_func, + prog->jited_len, unregister, + prog->aux->ksym.name); + } else { + for (i = 0; i < prog->aux->func_cnt; i++) { + struct bpf_prog *subprog = prog->aux->func[i]; + + perf_event_ksymbol( + PERF_RECORD_KSYMBOL_TYPE_BPF, + (u64)(unsigned long)subprog->bpf_func, + subprog->jited_len, unregister, + subprog->aux->ksym.name); + } + } +} + +void perf_event_bpf_event(struct bpf_prog *prog, + enum perf_bpf_event_type type, + u16 flags) +{ + struct perf_bpf_event bpf_event; + + if (type <= PERF_BPF_EVENT_UNKNOWN || + type >= PERF_BPF_EVENT_MAX) + return; + + switch (type) { + case PERF_BPF_EVENT_PROG_LOAD: + case PERF_BPF_EVENT_PROG_UNLOAD: + if (atomic_read(&nr_ksymbol_events)) + perf_event_bpf_emit_ksymbols(prog, type); + break; + default: + break; + } + + if (!atomic_read(&nr_bpf_events)) + return; + + bpf_event = (struct perf_bpf_event){ + .prog = prog, + .event_id = { + .header = { + .type = PERF_RECORD_BPF_EVENT, + .size = sizeof(bpf_event.event_id), + }, + .type = type, + .flags = flags, + .id = prog->aux->id, + }, + }; + + BUILD_BUG_ON(BPF_TAG_SIZE % sizeof(u64)); + + memcpy(bpf_event.event_id.tag, prog->tag, BPF_TAG_SIZE); + perf_iterate_sb(perf_event_bpf_output, &bpf_event, NULL); +} + +struct perf_text_poke_event { + const void *old_bytes; + const void *new_bytes; + size_t pad; + u16 old_len; + u16 new_len; + + struct { + struct perf_event_header header; + + u64 addr; + } event_id; +}; + +static int perf_event_text_poke_match(struct perf_event *event) +{ + return event->attr.text_poke; +} + +static void perf_event_text_poke_output(struct perf_event *event, void *data) +{ + struct perf_text_poke_event *text_poke_event = data; + struct perf_output_handle handle; + struct perf_sample_data sample; + u64 padding = 0; + int ret; + + if (!perf_event_text_poke_match(event)) + return; + + perf_event_header__init_id(&text_poke_event->event_id.header, &sample, event); + + ret = perf_output_begin(&handle, &sample, event, + text_poke_event->event_id.header.size); + if (ret) + return; + + perf_output_put(&handle, text_poke_event->event_id); + perf_output_put(&handle, text_poke_event->old_len); + perf_output_put(&handle, text_poke_event->new_len); + + __output_copy(&handle, text_poke_event->old_bytes, text_poke_event->old_len); + __output_copy(&handle, text_poke_event->new_bytes, text_poke_event->new_len); + + if (text_poke_event->pad) + __output_copy(&handle, &padding, text_poke_event->pad); + + perf_event__output_id_sample(event, &handle, &sample); + + perf_output_end(&handle); +} + +void perf_event_text_poke(const void *addr, const void *old_bytes, + size_t old_len, const void *new_bytes, size_t new_len) +{ + struct perf_text_poke_event text_poke_event; + size_t tot, pad; + + if (!atomic_read(&nr_text_poke_events)) + return; + + tot = sizeof(text_poke_event.old_len) + old_len; + tot += sizeof(text_poke_event.new_len) + new_len; + pad = ALIGN(tot, sizeof(u64)) - tot; + + text_poke_event = (struct perf_text_poke_event){ + .old_bytes = old_bytes, + .new_bytes = new_bytes, + .pad = pad, + .old_len = old_len, + .new_len = new_len, + .event_id = { + .header = { + .type = PERF_RECORD_TEXT_POKE, + .misc = PERF_RECORD_MISC_KERNEL, + .size = sizeof(text_poke_event.event_id) + tot + pad, + }, + .addr = (unsigned long)addr, + }, + }; + + perf_iterate_sb(perf_event_text_poke_output, &text_poke_event, NULL); +} + +void perf_event_itrace_started(struct perf_event *event) +{ + event->attach_state |= PERF_ATTACH_ITRACE; +} + +static void perf_log_itrace_start(struct perf_event *event) +{ + struct perf_output_handle handle; + struct perf_sample_data sample; + struct perf_aux_event { + struct perf_event_header header; + u32 pid; + u32 tid; + } rec; + int ret; + + if (event->parent) + event = event->parent; + + if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) || + event->attach_state & PERF_ATTACH_ITRACE) + return; + + rec.header.type = PERF_RECORD_ITRACE_START; + rec.header.misc = 0; + rec.header.size = sizeof(rec); + rec.pid = perf_event_pid(event, current); + rec.tid = perf_event_tid(event, current); + + perf_event_header__init_id(&rec.header, &sample, event); + ret = perf_output_begin(&handle, &sample, event, rec.header.size); + + if (ret) + return; + + perf_output_put(&handle, rec); + perf_event__output_id_sample(event, &handle, &sample); + + perf_output_end(&handle); +} + +void perf_report_aux_output_id(struct perf_event *event, u64 hw_id) +{ + struct perf_output_handle handle; + struct perf_sample_data sample; + struct perf_aux_event { + struct perf_event_header header; + u64 hw_id; + } rec; + int ret; + + if (event->parent) + event = event->parent; + + rec.header.type = PERF_RECORD_AUX_OUTPUT_HW_ID; + rec.header.misc = 0; + rec.header.size = sizeof(rec); + rec.hw_id = hw_id; + + perf_event_header__init_id(&rec.header, &sample, event); + ret = perf_output_begin(&handle, &sample, event, rec.header.size); + + if (ret) + return; + + perf_output_put(&handle, rec); + perf_event__output_id_sample(event, &handle, &sample); + + perf_output_end(&handle); +} + +static int +__perf_event_account_interrupt(struct perf_event *event, int throttle) +{ + struct hw_perf_event *hwc = &event->hw; + int ret = 0; + u64 seq; + + seq = __this_cpu_read(perf_throttled_seq); + if (seq != hwc->interrupts_seq) { + hwc->interrupts_seq = seq; + hwc->interrupts = 1; + } else { + hwc->interrupts++; + if (unlikely(throttle && + hwc->interrupts > max_samples_per_tick)) { + __this_cpu_inc(perf_throttled_count); + tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS); + hwc->interrupts = MAX_INTERRUPTS; + perf_log_throttle(event, 0); + ret = 1; + } + } + + 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, true); + } + + return ret; +} + +int perf_event_account_interrupt(struct perf_event *event) +{ + return __perf_event_account_interrupt(event, 1); +} + +static inline bool sample_is_allowed(struct perf_event *event, struct pt_regs *regs) +{ + /* + * Due to interrupt latency (AKA "skid"), we may enter the + * kernel before taking an overflow, even if the PMU is only + * counting user events. + */ + if (event->attr.exclude_kernel && !user_mode(regs)) + return false; + + return true; +} + +/* + * Generic event overflow handling, sampling. + */ + +static int __perf_event_overflow(struct perf_event *event, + int throttle, struct perf_sample_data *data, + struct pt_regs *regs) +{ + int events = atomic_read(&event->event_limit); + 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; + + ret = __perf_event_account_interrupt(event, throttle); + + /* + * 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; + perf_event_disable_inatomic(event); + } + + if (event->attr.sigtrap) { + /* + * The desired behaviour of sigtrap vs invalid samples is a bit + * tricky; on the one hand, one should not loose the SIGTRAP if + * it is the first event, on the other hand, we should also not + * trigger the WARN or override the data address. + */ + bool valid_sample = sample_is_allowed(event, regs); + unsigned int pending_id = 1; + + if (regs) + pending_id = hash32_ptr((void *)instruction_pointer(regs)) ?: 1; + if (!event->pending_sigtrap) { + event->pending_sigtrap = pending_id; + local_inc(&event->ctx->nr_pending); + } else if (event->attr.exclude_kernel && valid_sample) { + /* + * Should not be able to return to user space without + * consuming pending_sigtrap; with exceptions: + * + * 1. Where !exclude_kernel, events can overflow again + * in the kernel without returning to user space. + * + * 2. Events that can overflow again before the IRQ- + * work without user space progress (e.g. hrtimer). + * To approximate progress (with false negatives), + * check 32-bit hash of the current IP. + */ + WARN_ON_ONCE(event->pending_sigtrap != pending_id); + } + + event->pending_addr = 0; + if (valid_sample && (data->sample_flags & PERF_SAMPLE_ADDR)) + event->pending_addr = data->addr; + irq_work_queue(&event->pending_irq); + } + + READ_ONCE(event->overflow_handler)(event, data, regs); + + if (*perf_event_fasync(event) && event->pending_kill) { + event->pending_wakeup = 1; + irq_work_queue(&event->pending_irq); + } + + return ret; +} + +int perf_event_overflow(struct perf_event *event, + struct perf_sample_data *data, + struct pt_regs *regs) +{ + return __perf_event_overflow(event, 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. + */ + +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, + struct perf_sample_data *data, + struct pt_regs *regs) +{ + struct hw_perf_event *hwc = &event->hw; + int throttle = 0; + + if (!overflow) + overflow = perf_swevent_set_period(event); + + if (hwc->interrupts == MAX_INTERRUPTS) + return; + + for (; overflow; overflow--) { + if (__perf_event_overflow(event, 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, + 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 ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) { + data->period = nr; + return perf_swevent_overflow(event, 1, data, regs); + } else + data->period = event->hw.last_period; + + if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq) + return perf_swevent_overflow(event, 1, data, regs); + + if (local64_add_negative(nr, &hwc->period_left)) + return; + + perf_swevent_overflow(event, 0, 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, + struct perf_sample_data *data, + struct pt_regs *regs) +{ + struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable); + struct perf_event *event; + 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, head, hlist_entry) { + if (perf_swevent_match(event, type, event_id, data, regs)) + perf_swevent_event(event, nr, data, regs); + } +end: + rcu_read_unlock(); +} + +DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]); + +int perf_swevent_get_recursion_context(void) +{ + struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable); + + return get_recursion_context(swhash->recursion); +} +EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context); + +void perf_swevent_put_recursion_context(int rctx) +{ + struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable); + + put_recursion_context(swhash->recursion, rctx); +} + +void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr) +{ + struct perf_sample_data data; + + if (WARN_ON_ONCE(!regs)) + return; + + perf_sample_data_init(&data, addr, 0); + do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs); +} + +void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr) +{ + int rctx; + + preempt_disable_notrace(); + rctx = perf_swevent_get_recursion_context(); + if (unlikely(rctx < 0)) + goto fail; + + ___perf_sw_event(event_id, nr, regs, addr); + + perf_swevent_put_recursion_context(rctx); +fail: + 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 = this_cpu_ptr(&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); + perf_event_update_userpage(event); + + 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(struct swevent_htable *swhash) +{ + struct swevent_hlist *hlist = swevent_hlist_deref(swhash); + + if (!hlist) + return; + + RCU_INIT_POINTER(swhash->swevent_hlist, NULL); + kfree_rcu(hlist, rcu_head); +} + +static void swevent_hlist_put_cpu(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(void) +{ + int cpu; + + for_each_possible_cpu(cpu) + swevent_hlist_put_cpu(cpu); +} + +static int swevent_hlist_get_cpu(int cpu) +{ + struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); + int err = 0; + + mutex_lock(&swhash->hlist_mutex); + if (!swevent_hlist_deref(swhash) && + cpumask_test_cpu(cpu, perf_online_mask)) { + 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(void) +{ + int err, cpu, failed_cpu; + + mutex_lock(&pmus_lock); + for_each_possible_cpu(cpu) { + err = swevent_hlist_get_cpu(cpu); + if (err) { + failed_cpu = cpu; + goto fail; + } + } + mutex_unlock(&pmus_lock); + return 0; +fail: + for_each_possible_cpu(cpu) { + if (cpu == failed_cpu) + break; + swevent_hlist_put_cpu(cpu); + } + mutex_unlock(&pmus_lock); + return err; +} + +struct static_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); + + static_key_slow_dec(&perf_swevent_enabled[event_id]); + swevent_hlist_put(); +} + +static int perf_swevent_init(struct perf_event *event) +{ + u64 event_id = event->attr.config; + + if (event->attr.type != PERF_TYPE_SOFTWARE) + return -ENOENT; + + /* + * no branch sampling for software events + */ + if (has_branch_stack(event)) + return -EOPNOTSUPP; + + 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(); + if (err) + return err; + + static_key_slow_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, + + .capabilities = PERF_PMU_CAP_NO_NMI, + + .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->frag.data; + + /* only top level events have filters set */ + if (event->parent) + event = event->parent; + + 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; + /* + * If exclude_kernel, only trace user-space tracepoints (uprobes) + */ + if (event->attr.exclude_kernel && !user_mode(regs)) + return 0; + + if (!perf_tp_filter_match(event, data)) + return 0; + + return 1; +} + +void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx, + struct trace_event_call *call, u64 count, + struct pt_regs *regs, struct hlist_head *head, + struct task_struct *task) +{ + if (bpf_prog_array_valid(call)) { + *(struct pt_regs **)raw_data = regs; + if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) { + perf_swevent_put_recursion_context(rctx); + return; + } + } + perf_tp_event(call->event.type, count, raw_data, size, regs, head, + rctx, task); +} +EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit); + +void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size, + struct pt_regs *regs, struct hlist_head *head, int rctx, + struct task_struct *task) +{ + struct perf_sample_data data; + struct perf_event *event; + + struct perf_raw_record raw = { + .frag = { + .size = entry_size, + .data = record, + }, + }; + + perf_sample_data_init(&data, 0, 0); + data.raw = &raw; + data.sample_flags |= PERF_SAMPLE_RAW; + + perf_trace_buf_update(record, event_type); + + hlist_for_each_entry_rcu(event, head, hlist_entry) { + if (perf_tp_event_match(event, &data, regs)) + perf_swevent_event(event, count, &data, regs); + } + + /* + * If we got specified a target task, also iterate its context and + * deliver this event there too. + */ + if (task && task != current) { + struct perf_event_context *ctx; + struct trace_entry *entry = record; + + rcu_read_lock(); + ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]); + if (!ctx) + goto unlock; + + list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { + if (event->cpu != smp_processor_id()) + continue; + if (event->attr.type != PERF_TYPE_TRACEPOINT) + continue; + if (event->attr.config != entry->type) + continue; + /* Cannot deliver synchronous signal to other task. */ + if (event->attr.sigtrap) + continue; + if (perf_tp_event_match(event, &data, regs)) + perf_swevent_event(event, count, &data, regs); + } +unlock: + rcu_read_unlock(); + } + + 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; + + /* + * no branch sampling for tracepoint events + */ + if (has_branch_stack(event)) + return -EOPNOTSUPP; + + 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, +}; + +#if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS) +/* + * Flags in config, used by dynamic PMU kprobe and uprobe + * The flags should match following PMU_FORMAT_ATTR(). + * + * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe + * if not set, create kprobe/uprobe + * + * The following values specify a reference counter (or semaphore in the + * terminology of tools like dtrace, systemtap, etc.) Userspace Statically + * Defined Tracepoints (USDT). Currently, we use 40 bit for the offset. + * + * PERF_UPROBE_REF_CTR_OFFSET_BITS # of bits in config as th offset + * PERF_UPROBE_REF_CTR_OFFSET_SHIFT # of bits to shift left + */ +enum perf_probe_config { + PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */ + PERF_UPROBE_REF_CTR_OFFSET_BITS = 32, + PERF_UPROBE_REF_CTR_OFFSET_SHIFT = 64 - PERF_UPROBE_REF_CTR_OFFSET_BITS, +}; + +PMU_FORMAT_ATTR(retprobe, "config:0"); +#endif + +#ifdef CONFIG_KPROBE_EVENTS +static struct attribute *kprobe_attrs[] = { + &format_attr_retprobe.attr, + NULL, +}; + +static struct attribute_group kprobe_format_group = { + .name = "format", + .attrs = kprobe_attrs, +}; + +static const struct attribute_group *kprobe_attr_groups[] = { + &kprobe_format_group, + NULL, +}; + +static int perf_kprobe_event_init(struct perf_event *event); +static struct pmu perf_kprobe = { + .task_ctx_nr = perf_sw_context, + .event_init = perf_kprobe_event_init, + .add = perf_trace_add, + .del = perf_trace_del, + .start = perf_swevent_start, + .stop = perf_swevent_stop, + .read = perf_swevent_read, + .attr_groups = kprobe_attr_groups, +}; + +static int perf_kprobe_event_init(struct perf_event *event) +{ + int err; + bool is_retprobe; + + if (event->attr.type != perf_kprobe.type) + return -ENOENT; + + if (!perfmon_capable()) + return -EACCES; + + /* + * no branch sampling for probe events + */ + if (has_branch_stack(event)) + return -EOPNOTSUPP; + + is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE; + err = perf_kprobe_init(event, is_retprobe); + if (err) + return err; + + event->destroy = perf_kprobe_destroy; + + return 0; +} +#endif /* CONFIG_KPROBE_EVENTS */ + +#ifdef CONFIG_UPROBE_EVENTS +PMU_FORMAT_ATTR(ref_ctr_offset, "config:32-63"); + +static struct attribute *uprobe_attrs[] = { + &format_attr_retprobe.attr, + &format_attr_ref_ctr_offset.attr, + NULL, +}; + +static struct attribute_group uprobe_format_group = { + .name = "format", + .attrs = uprobe_attrs, +}; + +static const struct attribute_group *uprobe_attr_groups[] = { + &uprobe_format_group, + NULL, +}; + +static int perf_uprobe_event_init(struct perf_event *event); +static struct pmu perf_uprobe = { + .task_ctx_nr = perf_sw_context, + .event_init = perf_uprobe_event_init, + .add = perf_trace_add, + .del = perf_trace_del, + .start = perf_swevent_start, + .stop = perf_swevent_stop, + .read = perf_swevent_read, + .attr_groups = uprobe_attr_groups, +}; + +static int perf_uprobe_event_init(struct perf_event *event) +{ + int err; + unsigned long ref_ctr_offset; + bool is_retprobe; + + if (event->attr.type != perf_uprobe.type) + return -ENOENT; + + if (!perfmon_capable()) + return -EACCES; + + /* + * no branch sampling for probe events + */ + if (has_branch_stack(event)) + return -EOPNOTSUPP; + + is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE; + ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT; + err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe); + if (err) + return err; + + event->destroy = perf_uprobe_destroy; + + return 0; +} +#endif /* CONFIG_UPROBE_EVENTS */ + +static inline void perf_tp_register(void) +{ + perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT); +#ifdef CONFIG_KPROBE_EVENTS + perf_pmu_register(&perf_kprobe, "kprobe", -1); +#endif +#ifdef CONFIG_UPROBE_EVENTS + perf_pmu_register(&perf_uprobe, "uprobe", -1); +#endif +} + +static void perf_event_free_filter(struct perf_event *event) +{ + ftrace_profile_free_filter(event); +} + +#ifdef CONFIG_BPF_SYSCALL +static void bpf_overflow_handler(struct perf_event *event, + struct perf_sample_data *data, + struct pt_regs *regs) +{ + struct bpf_perf_event_data_kern ctx = { + .data = data, + .event = event, + }; + struct bpf_prog *prog; + int ret = 0; + + ctx.regs = perf_arch_bpf_user_pt_regs(regs); + if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) + goto out; + rcu_read_lock(); + prog = READ_ONCE(event->prog); + if (prog) { + if (prog->call_get_stack && + (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) && + !(data->sample_flags & PERF_SAMPLE_CALLCHAIN)) { + data->callchain = perf_callchain(event, regs); + data->sample_flags |= PERF_SAMPLE_CALLCHAIN; + } + + ret = bpf_prog_run(prog, &ctx); + } + rcu_read_unlock(); +out: + __this_cpu_dec(bpf_prog_active); + if (!ret) + return; + + event->orig_overflow_handler(event, data, regs); +} + +static int perf_event_set_bpf_handler(struct perf_event *event, + struct bpf_prog *prog, + u64 bpf_cookie) +{ + if (event->overflow_handler_context) + /* hw breakpoint or kernel counter */ + return -EINVAL; + + if (event->prog) + return -EEXIST; + + if (prog->type != BPF_PROG_TYPE_PERF_EVENT) + return -EINVAL; + + if (event->attr.precise_ip && + prog->call_get_stack && + (!(event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) || + event->attr.exclude_callchain_kernel || + event->attr.exclude_callchain_user)) { + /* + * On perf_event with precise_ip, calling bpf_get_stack() + * may trigger unwinder warnings and occasional crashes. + * bpf_get_[stack|stackid] works around this issue by using + * callchain attached to perf_sample_data. If the + * perf_event does not full (kernel and user) callchain + * attached to perf_sample_data, do not allow attaching BPF + * program that calls bpf_get_[stack|stackid]. + */ + return -EPROTO; + } + + event->prog = prog; + event->bpf_cookie = bpf_cookie; + event->orig_overflow_handler = READ_ONCE(event->overflow_handler); + WRITE_ONCE(event->overflow_handler, bpf_overflow_handler); + return 0; +} + +static void perf_event_free_bpf_handler(struct perf_event *event) +{ + struct bpf_prog *prog = event->prog; + + if (!prog) + return; + + WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler); + event->prog = NULL; + bpf_prog_put(prog); +} +#else +static int perf_event_set_bpf_handler(struct perf_event *event, + struct bpf_prog *prog, + u64 bpf_cookie) +{ + return -EOPNOTSUPP; +} +static void perf_event_free_bpf_handler(struct perf_event *event) +{ +} +#endif + +/* + * returns true if the event is a tracepoint, or a kprobe/upprobe created + * with perf_event_open() + */ +static inline bool perf_event_is_tracing(struct perf_event *event) +{ + if (event->pmu == &perf_tracepoint) + return true; +#ifdef CONFIG_KPROBE_EVENTS + if (event->pmu == &perf_kprobe) + return true; +#endif +#ifdef CONFIG_UPROBE_EVENTS + if (event->pmu == &perf_uprobe) + return true; +#endif + return false; +} + +int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog, + u64 bpf_cookie) +{ + bool is_kprobe, is_uprobe, is_tracepoint, is_syscall_tp; + + if (!perf_event_is_tracing(event)) + return perf_event_set_bpf_handler(event, prog, bpf_cookie); + + is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_KPROBE; + is_uprobe = event->tp_event->flags & TRACE_EVENT_FL_UPROBE; + is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT; + is_syscall_tp = is_syscall_trace_event(event->tp_event); + if (!is_kprobe && !is_uprobe && !is_tracepoint && !is_syscall_tp) + /* bpf programs can only be attached to u/kprobe or tracepoint */ + return -EINVAL; + + if (((is_kprobe || is_uprobe) && prog->type != BPF_PROG_TYPE_KPROBE) || + (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) || + (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) + return -EINVAL; + + if (prog->type == BPF_PROG_TYPE_KPROBE && prog->aux->sleepable && !is_uprobe) + /* only uprobe programs are allowed to be sleepable */ + return -EINVAL; + + /* Kprobe override only works for kprobes, not uprobes. */ + if (prog->kprobe_override && !is_kprobe) + return -EINVAL; + + if (is_tracepoint || is_syscall_tp) { + int off = trace_event_get_offsets(event->tp_event); + + if (prog->aux->max_ctx_offset > off) + return -EACCES; + } + + return perf_event_attach_bpf_prog(event, prog, bpf_cookie); +} + +void perf_event_free_bpf_prog(struct perf_event *event) +{ + if (!perf_event_is_tracing(event)) { + perf_event_free_bpf_handler(event); + return; + } + perf_event_detach_bpf_prog(event); +} + +#else + +static inline void perf_tp_register(void) +{ +} + +static void perf_event_free_filter(struct perf_event *event) +{ +} + +int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog, + u64 bpf_cookie) +{ + return -ENOENT; +} + +void perf_event_free_bpf_prog(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, 0); + + if (!bp->hw.state && !perf_exclude_event(bp, regs)) + perf_swevent_event(bp, 1, &sample, regs); +} +#endif + +/* + * Allocate a new address filter + */ +static struct perf_addr_filter * +perf_addr_filter_new(struct perf_event *event, struct list_head *filters) +{ + int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu); + struct perf_addr_filter *filter; + + filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node); + if (!filter) + return NULL; + + INIT_LIST_HEAD(&filter->entry); + list_add_tail(&filter->entry, filters); + + return filter; +} + +static void free_filters_list(struct list_head *filters) +{ + struct perf_addr_filter *filter, *iter; + + list_for_each_entry_safe(filter, iter, filters, entry) { + path_put(&filter->path); + list_del(&filter->entry); + kfree(filter); + } +} + +/* + * Free existing address filters and optionally install new ones + */ +static void perf_addr_filters_splice(struct perf_event *event, + struct list_head *head) +{ + unsigned long flags; + LIST_HEAD(list); + + if (!has_addr_filter(event)) + return; + + /* don't bother with children, they don't have their own filters */ + if (event->parent) + return; + + raw_spin_lock_irqsave(&event->addr_filters.lock, flags); + + list_splice_init(&event->addr_filters.list, &list); + if (head) + list_splice(head, &event->addr_filters.list); + + raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags); + + free_filters_list(&list); +} + +/* + * Scan through mm's vmas and see if one of them matches the + * @filter; if so, adjust filter's address range. + * Called with mm::mmap_lock down for reading. + */ +static void perf_addr_filter_apply(struct perf_addr_filter *filter, + struct mm_struct *mm, + struct perf_addr_filter_range *fr) +{ + struct vm_area_struct *vma; + VMA_ITERATOR(vmi, mm, 0); + + for_each_vma(vmi, vma) { + if (!vma->vm_file) + continue; + + if (perf_addr_filter_vma_adjust(filter, vma, fr)) + return; + } +} + +/* + * Update event's address range filters based on the + * task's existing mappings, if any. + */ +static void perf_event_addr_filters_apply(struct perf_event *event) +{ + struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); + struct task_struct *task = READ_ONCE(event->ctx->task); + struct perf_addr_filter *filter; + struct mm_struct *mm = NULL; + unsigned int count = 0; + unsigned long flags; + + /* + * We may observe TASK_TOMBSTONE, which means that the event tear-down + * will stop on the parent's child_mutex that our caller is also holding + */ + if (task == TASK_TOMBSTONE) + return; + + if (ifh->nr_file_filters) { + mm = get_task_mm(task); + if (!mm) + goto restart; + + mmap_read_lock(mm); + } + + raw_spin_lock_irqsave(&ifh->lock, flags); + list_for_each_entry(filter, &ifh->list, entry) { + if (filter->path.dentry) { + /* + * Adjust base offset if the filter is associated to a + * binary that needs to be mapped: + */ + event->addr_filter_ranges[count].start = 0; + event->addr_filter_ranges[count].size = 0; + + perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]); + } else { + event->addr_filter_ranges[count].start = filter->offset; + event->addr_filter_ranges[count].size = filter->size; + } + + count++; + } + + event->addr_filters_gen++; + raw_spin_unlock_irqrestore(&ifh->lock, flags); + + if (ifh->nr_file_filters) { + mmap_read_unlock(mm); + + mmput(mm); + } + +restart: + perf_event_stop(event, 1); +} + +/* + * Address range filtering: limiting the data to certain + * instruction address ranges. Filters are ioctl()ed to us from + * userspace as ascii strings. + * + * Filter string format: + * + * ACTION RANGE_SPEC + * where ACTION is one of the + * * "filter": limit the trace to this region + * * "start": start tracing from this address + * * "stop": stop tracing at this address/region; + * RANGE_SPEC is + * * for kernel addresses: <start address>[/<size>] + * * for object files: <start address>[/<size>]@</path/to/object/file> + * + * if <size> is not specified or is zero, the range is treated as a single + * address; not valid for ACTION=="filter". + */ +enum { + IF_ACT_NONE = -1, + IF_ACT_FILTER, + IF_ACT_START, + IF_ACT_STOP, + IF_SRC_FILE, + IF_SRC_KERNEL, + IF_SRC_FILEADDR, + IF_SRC_KERNELADDR, +}; + +enum { + IF_STATE_ACTION = 0, + IF_STATE_SOURCE, + IF_STATE_END, +}; + +static const match_table_t if_tokens = { + { IF_ACT_FILTER, "filter" }, + { IF_ACT_START, "start" }, + { IF_ACT_STOP, "stop" }, + { IF_SRC_FILE, "%u/%u@%s" }, + { IF_SRC_KERNEL, "%u/%u" }, + { IF_SRC_FILEADDR, "%u@%s" }, + { IF_SRC_KERNELADDR, "%u" }, + { IF_ACT_NONE, NULL }, +}; + +/* + * Address filter string parser + */ +static int +perf_event_parse_addr_filter(struct perf_event *event, char *fstr, + struct list_head *filters) +{ + struct perf_addr_filter *filter = NULL; + char *start, *orig, *filename = NULL; + substring_t args[MAX_OPT_ARGS]; + int state = IF_STATE_ACTION, token; + unsigned int kernel = 0; + int ret = -EINVAL; + + orig = fstr = kstrdup(fstr, GFP_KERNEL); + if (!fstr) + return -ENOMEM; + + while ((start = strsep(&fstr, " ,\n")) != NULL) { + static const enum perf_addr_filter_action_t actions[] = { + [IF_ACT_FILTER] = PERF_ADDR_FILTER_ACTION_FILTER, + [IF_ACT_START] = PERF_ADDR_FILTER_ACTION_START, + [IF_ACT_STOP] = PERF_ADDR_FILTER_ACTION_STOP, + }; + ret = -EINVAL; + + if (!*start) + continue; + + /* filter definition begins */ + if (state == IF_STATE_ACTION) { + filter = perf_addr_filter_new(event, filters); + if (!filter) + goto fail; + } + + token = match_token(start, if_tokens, args); + switch (token) { + case IF_ACT_FILTER: + case IF_ACT_START: + case IF_ACT_STOP: + if (state != IF_STATE_ACTION) + goto fail; + + filter->action = actions[token]; + state = IF_STATE_SOURCE; + break; + + case IF_SRC_KERNELADDR: + case IF_SRC_KERNEL: + kernel = 1; + fallthrough; + + case IF_SRC_FILEADDR: + case IF_SRC_FILE: + if (state != IF_STATE_SOURCE) + goto fail; + + *args[0].to = 0; + ret = kstrtoul(args[0].from, 0, &filter->offset); + if (ret) + goto fail; + + if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) { + *args[1].to = 0; + ret = kstrtoul(args[1].from, 0, &filter->size); + if (ret) + goto fail; + } + + if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) { + int fpos = token == IF_SRC_FILE ? 2 : 1; + + kfree(filename); + filename = match_strdup(&args[fpos]); + if (!filename) { + ret = -ENOMEM; + goto fail; + } + } + + state = IF_STATE_END; + break; + + default: + goto fail; + } + + /* + * Filter definition is fully parsed, validate and install it. + * Make sure that it doesn't contradict itself or the event's + * attribute. + */ + if (state == IF_STATE_END) { + ret = -EINVAL; + + /* + * ACTION "filter" must have a non-zero length region + * specified. + */ + if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER && + !filter->size) + goto fail; + + if (!kernel) { + if (!filename) + goto fail; + + /* + * For now, we only support file-based filters + * in per-task events; doing so for CPU-wide + * events requires additional context switching + * trickery, since same object code will be + * mapped at different virtual addresses in + * different processes. + */ + ret = -EOPNOTSUPP; + if (!event->ctx->task) + goto fail; + + /* look up the path and grab its inode */ + ret = kern_path(filename, LOOKUP_FOLLOW, + &filter->path); + if (ret) + goto fail; + + ret = -EINVAL; + if (!filter->path.dentry || + !S_ISREG(d_inode(filter->path.dentry) + ->i_mode)) + goto fail; + + event->addr_filters.nr_file_filters++; + } + + /* ready to consume more filters */ + kfree(filename); + filename = NULL; + state = IF_STATE_ACTION; + filter = NULL; + kernel = 0; + } + } + + if (state != IF_STATE_ACTION) + goto fail; + + kfree(filename); + kfree(orig); + + return 0; + +fail: + kfree(filename); + free_filters_list(filters); + kfree(orig); + + return ret; +} + +static int +perf_event_set_addr_filter(struct perf_event *event, char *filter_str) +{ + LIST_HEAD(filters); + int ret; + + /* + * Since this is called in perf_ioctl() path, we're already holding + * ctx::mutex. + */ + lockdep_assert_held(&event->ctx->mutex); + + if (WARN_ON_ONCE(event->parent)) + return -EINVAL; + + ret = perf_event_parse_addr_filter(event, filter_str, &filters); + if (ret) + goto fail_clear_files; + + ret = event->pmu->addr_filters_validate(&filters); + if (ret) + goto fail_free_filters; + + /* remove existing filters, if any */ + perf_addr_filters_splice(event, &filters); + + /* install new filters */ + perf_event_for_each_child(event, perf_event_addr_filters_apply); + + return ret; + +fail_free_filters: + free_filters_list(&filters); + +fail_clear_files: + event->addr_filters.nr_file_filters = 0; + + return ret; +} + +static int perf_event_set_filter(struct perf_event *event, void __user *arg) +{ + int ret = -EINVAL; + char *filter_str; + + filter_str = strndup_user(arg, PAGE_SIZE); + if (IS_ERR(filter_str)) + return PTR_ERR(filter_str); + +#ifdef CONFIG_EVENT_TRACING + if (perf_event_is_tracing(event)) { + struct perf_event_context *ctx = event->ctx; + + /* + * Beware, here be dragons!! + * + * the tracepoint muck will deadlock against ctx->mutex, but + * the tracepoint stuff does not actually need it. So + * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we + * already have a reference on ctx. + * + * This can result in event getting moved to a different ctx, + * but that does not affect the tracepoint state. + */ + mutex_unlock(&ctx->mutex); + ret = ftrace_profile_set_filter(event, event->attr.config, filter_str); + mutex_lock(&ctx->mutex); + } else +#endif + if (has_addr_filter(event)) + ret = perf_event_set_addr_filter(event, filter_str); + + kfree(filter_str); + return ret; +} + +/* + * 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, event->hw.last_period); + regs = get_irq_regs(); + + if (regs && !perf_exclude_event(event, regs)) { + if (!(event->attr.exclude_idle && is_idle_task(current))) + if (__perf_event_overflow(event, 1, &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(&hwc->hrtimer, ns_to_ktime(period), + HRTIMER_MODE_REL_PINNED_HARD); +} + +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_HARD); + 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); + hwc->last_period = 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); + perf_event_update_userpage(event); + + 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; + + /* + * no branch sampling for software events + */ + if (has_branch_stack(event)) + return -EOPNOTSUPP; + + perf_swevent_init_hrtimer(event); + + return 0; +} + +static struct pmu perf_cpu_clock = { + .task_ctx_nr = perf_sw_context, + + .capabilities = PERF_PMU_CAP_NO_NMI, + + .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); + perf_event_update_userpage(event); + + 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; + + /* + * no branch sampling for software events + */ + if (has_branch_stack(event)) + return -EOPNOTSUPP; + + perf_swevent_init_hrtimer(event); + + return 0; +} + +static struct pmu perf_task_clock = { + .task_ctx_nr = perf_sw_context, + + .capabilities = PERF_PMU_CAP_NO_NMI, + + .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 void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags) +{ +} + +static int perf_pmu_nop_int(struct pmu *pmu) +{ + return 0; +} + +static int perf_event_nop_int(struct perf_event *event, u64 value) +{ + return 0; +} + +static DEFINE_PER_CPU(unsigned int, nop_txn_flags); + +static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags) +{ + __this_cpu_write(nop_txn_flags, flags); + + if (flags & ~PERF_PMU_TXN_ADD) + return; + + perf_pmu_disable(pmu); +} + +static int perf_pmu_commit_txn(struct pmu *pmu) +{ + unsigned int flags = __this_cpu_read(nop_txn_flags); + + __this_cpu_write(nop_txn_flags, 0); + + if (flags & ~PERF_PMU_TXN_ADD) + return 0; + + perf_pmu_enable(pmu); + return 0; +} + +static void perf_pmu_cancel_txn(struct pmu *pmu) +{ + unsigned int flags = __this_cpu_read(nop_txn_flags); + + __this_cpu_write(nop_txn_flags, 0); + + if (flags & ~PERF_PMU_TXN_ADD) + return; + + perf_pmu_enable(pmu); +} + +static int perf_event_idx_default(struct perf_event *event) +{ + return 0; +} + +/* + * Ensures all contexts with the same task_ctx_nr have the same + * pmu_cpu_context too. + */ +static struct perf_cpu_context __percpu *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 free_pmu_context(struct pmu *pmu) +{ + /* + * Static contexts such as perf_sw_context have a global lifetime + * and may be shared between different PMUs. Avoid freeing them + * when a single PMU is going away. + */ + if (pmu->task_ctx_nr > perf_invalid_context) + return; + + free_percpu(pmu->pmu_cpu_context); +} + +/* + * Let userspace know that this PMU supports address range filtering: + */ +static ssize_t nr_addr_filters_show(struct device *dev, + struct device_attribute *attr, + char *page) +{ + struct pmu *pmu = dev_get_drvdata(dev); + + return scnprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters); +} +DEVICE_ATTR_RO(nr_addr_filters); + +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 scnprintf(page, PAGE_SIZE - 1, "%d\n", pmu->type); +} +static DEVICE_ATTR_RO(type); + +static ssize_t +perf_event_mux_interval_ms_show(struct device *dev, + struct device_attribute *attr, + char *page) +{ + struct pmu *pmu = dev_get_drvdata(dev); + + return scnprintf(page, PAGE_SIZE - 1, "%d\n", pmu->hrtimer_interval_ms); +} + +static DEFINE_MUTEX(mux_interval_mutex); + +static ssize_t +perf_event_mux_interval_ms_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct pmu *pmu = dev_get_drvdata(dev); + int timer, cpu, ret; + + ret = kstrtoint(buf, 0, &timer); + if (ret) + return ret; + + if (timer < 1) + return -EINVAL; + + /* same value, noting to do */ + if (timer == pmu->hrtimer_interval_ms) + return count; + + mutex_lock(&mux_interval_mutex); + pmu->hrtimer_interval_ms = timer; + + /* update all cpuctx for this PMU */ + cpus_read_lock(); + for_each_online_cpu(cpu) { + struct perf_cpu_context *cpuctx; + cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); + cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer); + + cpu_function_call(cpu, perf_mux_hrtimer_restart_ipi, cpuctx); + } + cpus_read_unlock(); + mutex_unlock(&mux_interval_mutex); + + return count; +} +static DEVICE_ATTR_RW(perf_event_mux_interval_ms); + +static struct attribute *pmu_dev_attrs[] = { + &dev_attr_type.attr, + &dev_attr_perf_event_mux_interval_ms.attr, + NULL, +}; +ATTRIBUTE_GROUPS(pmu_dev); + +static int pmu_bus_running; +static struct bus_type pmu_bus = { + .name = "event_source", + .dev_groups = pmu_dev_groups, +}; + +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; + + pmu->dev->groups = pmu->attr_groups; + device_initialize(pmu->dev); + + dev_set_drvdata(pmu->dev, pmu); + pmu->dev->bus = &pmu_bus; + pmu->dev->release = pmu_dev_release; + + ret = dev_set_name(pmu->dev, "%s", pmu->name); + if (ret) + goto free_dev; + + ret = device_add(pmu->dev); + if (ret) + goto free_dev; + + /* For PMUs with address filters, throw in an extra attribute: */ + if (pmu->nr_addr_filters) + ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters); + + if (ret) + goto del_dev; + + if (pmu->attr_update) + ret = sysfs_update_groups(&pmu->dev->kobj, pmu->attr_update); + + if (ret) + goto del_dev; + +out: + return ret; + +del_dev: + device_del(pmu->dev); + +free_dev: + put_device(pmu->dev); + goto out; +} + +static struct lock_class_key cpuctx_mutex; +static struct lock_class_key cpuctx_lock; + +int perf_pmu_register(struct pmu *pmu, const char *name, int type) +{ + int cpu, ret, max = PERF_TYPE_MAX; + + 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 != PERF_TYPE_SOFTWARE) { + if (type >= 0) + max = type; + + ret = idr_alloc(&pmu_idr, pmu, max, 0, GFP_KERNEL); + if (ret < 0) + goto free_pdc; + + WARN_ON(type >= 0 && ret != type); + + type = ret; + } + pmu->type = type; + + if (pmu_bus_running) { + ret = pmu_dev_alloc(pmu); + if (ret) + goto free_idr; + } + +skip_type: + if (pmu->task_ctx_nr == perf_hw_context) { + static int hw_context_taken = 0; + + /* + * Other than systems with heterogeneous CPUs, it never makes + * sense for two PMUs to share perf_hw_context. PMUs which are + * uncore must use perf_invalid_context. + */ + if (WARN_ON_ONCE(hw_context_taken && + !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS))) + pmu->task_ctx_nr = perf_invalid_context; + + hw_context_taken = 1; + } + + pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr); + if (pmu->pmu_cpu_context) + goto got_cpu_context; + + ret = -ENOMEM; + 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); + lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock); + cpuctx->ctx.pmu = pmu; + cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask); + + __perf_mux_hrtimer_init(cpuctx, cpu); + + cpuctx->heap_size = ARRAY_SIZE(cpuctx->heap_default); + cpuctx->heap = cpuctx->heap_default; + } + +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_txn; + 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; + } + + if (!pmu->check_period) + pmu->check_period = perf_event_nop_int; + + if (!pmu->event_idx) + pmu->event_idx = perf_event_idx_default; + + /* + * Ensure the TYPE_SOFTWARE PMUs are at the head of the list, + * since these cannot be in the IDR. This way the linear search + * is fast, provided a valid software event is provided. + */ + if (type == PERF_TYPE_SOFTWARE || !name) + list_add_rcu(&pmu->entry, &pmus); + else + list_add_tail_rcu(&pmu->entry, &pmus); + + atomic_set(&pmu->exclusive_cnt, 0); + 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_SOFTWARE) + idr_remove(&pmu_idr, pmu->type); + +free_pdc: + free_percpu(pmu->pmu_disable_count); + goto unlock; +} +EXPORT_SYMBOL_GPL(perf_pmu_register); + +void perf_pmu_unregister(struct pmu *pmu) +{ + mutex_lock(&pmus_lock); + list_del_rcu(&pmu->entry); + + /* + * 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_SOFTWARE) + idr_remove(&pmu_idr, pmu->type); + if (pmu_bus_running) { + if (pmu->nr_addr_filters) + device_remove_file(pmu->dev, &dev_attr_nr_addr_filters); + device_del(pmu->dev); + put_device(pmu->dev); + } + free_pmu_context(pmu); + mutex_unlock(&pmus_lock); +} +EXPORT_SYMBOL_GPL(perf_pmu_unregister); + +static inline bool has_extended_regs(struct perf_event *event) +{ + return (event->attr.sample_regs_user & PERF_REG_EXTENDED_MASK) || + (event->attr.sample_regs_intr & PERF_REG_EXTENDED_MASK); +} + +static int perf_try_init_event(struct pmu *pmu, struct perf_event *event) +{ + struct perf_event_context *ctx = NULL; + int ret; + + if (!try_module_get(pmu->module)) + return -ENODEV; + + /* + * A number of pmu->event_init() methods iterate the sibling_list to, + * for example, validate if the group fits on the PMU. Therefore, + * if this is a sibling event, acquire the ctx->mutex to protect + * the sibling_list. + */ + if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) { + /* + * This ctx->mutex can nest when we're called through + * inheritance. See the perf_event_ctx_lock_nested() comment. + */ + ctx = perf_event_ctx_lock_nested(event->group_leader, + SINGLE_DEPTH_NESTING); + BUG_ON(!ctx); + } + + event->pmu = pmu; + ret = pmu->event_init(event); + + if (ctx) + perf_event_ctx_unlock(event->group_leader, ctx); + + if (!ret) { + if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) && + has_extended_regs(event)) + ret = -EOPNOTSUPP; + + if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE && + event_has_any_exclude_flag(event)) + ret = -EINVAL; + + if (ret && event->destroy) + event->destroy(event); + } + + if (ret) + module_put(pmu->module); + + return ret; +} + +static struct pmu *perf_init_event(struct perf_event *event) +{ + bool extended_type = false; + int idx, type, ret; + struct pmu *pmu; + + idx = srcu_read_lock(&pmus_srcu); + + /* Try parent's PMU first: */ + if (event->parent && event->parent->pmu) { + pmu = event->parent->pmu; + ret = perf_try_init_event(pmu, event); + if (!ret) + goto unlock; + } + + /* + * PERF_TYPE_HARDWARE and PERF_TYPE_HW_CACHE + * are often aliases for PERF_TYPE_RAW. + */ + type = event->attr.type; + if (type == PERF_TYPE_HARDWARE || type == PERF_TYPE_HW_CACHE) { + type = event->attr.config >> PERF_PMU_TYPE_SHIFT; + if (!type) { + type = PERF_TYPE_RAW; + } else { + extended_type = true; + event->attr.config &= PERF_HW_EVENT_MASK; + } + } + +again: + rcu_read_lock(); + pmu = idr_find(&pmu_idr, type); + rcu_read_unlock(); + if (pmu) { + if (event->attr.type != type && type != PERF_TYPE_RAW && + !(pmu->capabilities & PERF_PMU_CAP_EXTENDED_HW_TYPE)) + goto fail; + + ret = perf_try_init_event(pmu, event); + if (ret == -ENOENT && event->attr.type != type && !extended_type) { + type = event->attr.type; + goto again; + } + + if (ret) + pmu = ERR_PTR(ret); + + goto unlock; + } + + list_for_each_entry_rcu(pmu, &pmus, entry, lockdep_is_held(&pmus_srcu)) { + ret = perf_try_init_event(pmu, event); + if (!ret) + goto unlock; + + if (ret != -ENOENT) { + pmu = ERR_PTR(ret); + goto unlock; + } + } +fail: + pmu = ERR_PTR(-ENOENT); +unlock: + srcu_read_unlock(&pmus_srcu, idx); + + return pmu; +} + +static void attach_sb_event(struct perf_event *event) +{ + struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu); + + raw_spin_lock(&pel->lock); + list_add_rcu(&event->sb_list, &pel->list); + raw_spin_unlock(&pel->lock); +} + +/* + * We keep a list of all !task (and therefore per-cpu) events + * that need to receive side-band records. + * + * This avoids having to scan all the various PMU per-cpu contexts + * looking for them. + */ +static void account_pmu_sb_event(struct perf_event *event) +{ + if (is_sb_event(event)) + attach_sb_event(event); +} + +static void account_event_cpu(struct perf_event *event, int cpu) +{ + if (event->parent) + return; + + if (is_cgroup_event(event)) + atomic_inc(&per_cpu(perf_cgroup_events, cpu)); +} + +/* Freq events need the tick to stay alive (see perf_event_task_tick). */ +static void account_freq_event_nohz(void) +{ +#ifdef CONFIG_NO_HZ_FULL + /* Lock so we don't race with concurrent unaccount */ + spin_lock(&nr_freq_lock); + if (atomic_inc_return(&nr_freq_events) == 1) + tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS); + spin_unlock(&nr_freq_lock); +#endif +} + +static void account_freq_event(void) +{ + if (tick_nohz_full_enabled()) + account_freq_event_nohz(); + else + atomic_inc(&nr_freq_events); +} + + +static void account_event(struct perf_event *event) +{ + bool inc = false; + + if (event->parent) + return; + + if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB)) + inc = true; + if (event->attr.mmap || event->attr.mmap_data) + atomic_inc(&nr_mmap_events); + if (event->attr.build_id) + atomic_inc(&nr_build_id_events); + if (event->attr.comm) + atomic_inc(&nr_comm_events); + if (event->attr.namespaces) + atomic_inc(&nr_namespaces_events); + if (event->attr.cgroup) + atomic_inc(&nr_cgroup_events); + if (event->attr.task) + atomic_inc(&nr_task_events); + if (event->attr.freq) + account_freq_event(); + if (event->attr.context_switch) { + atomic_inc(&nr_switch_events); + inc = true; + } + if (has_branch_stack(event)) + inc = true; + if (is_cgroup_event(event)) + inc = true; + if (event->attr.ksymbol) + atomic_inc(&nr_ksymbol_events); + if (event->attr.bpf_event) + atomic_inc(&nr_bpf_events); + if (event->attr.text_poke) + atomic_inc(&nr_text_poke_events); + + if (inc) { + /* + * We need the mutex here because static_branch_enable() + * must complete *before* the perf_sched_count increment + * becomes visible. + */ + if (atomic_inc_not_zero(&perf_sched_count)) + goto enabled; + + mutex_lock(&perf_sched_mutex); + if (!atomic_read(&perf_sched_count)) { + static_branch_enable(&perf_sched_events); + /* + * Guarantee that all CPUs observe they key change and + * call the perf scheduling hooks before proceeding to + * install events that need them. + */ + synchronize_rcu(); + } + /* + * Now that we have waited for the sync_sched(), allow further + * increments to by-pass the mutex. + */ + atomic_inc(&perf_sched_count); + mutex_unlock(&perf_sched_mutex); + } +enabled: + + account_event_cpu(event, event->cpu); + + account_pmu_sb_event(event); +} + +/* + * Allocate and initialize an 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, + void *context, int cgroup_fd) +{ + struct pmu *pmu; + struct perf_event *event; + struct hw_perf_event *hwc; + long err = -EINVAL; + int node; + + if ((unsigned)cpu >= nr_cpu_ids) { + if (!task || cpu != -1) + return ERR_PTR(-EINVAL); + } + if (attr->sigtrap && !task) { + /* Requires a task: avoid signalling random tasks. */ + return ERR_PTR(-EINVAL); + } + + node = (cpu >= 0) ? cpu_to_node(cpu) : -1; + event = kmem_cache_alloc_node(perf_event_cache, GFP_KERNEL | __GFP_ZERO, + node); + 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->event_entry); + INIT_LIST_HEAD(&event->sibling_list); + INIT_LIST_HEAD(&event->active_list); + init_event_group(event); + INIT_LIST_HEAD(&event->rb_entry); + INIT_LIST_HEAD(&event->active_entry); + INIT_LIST_HEAD(&event->addr_filters.list); + INIT_HLIST_NODE(&event->hlist_entry); + + + init_waitqueue_head(&event->waitq); + init_irq_work(&event->pending_irq, perf_pending_irq); + init_task_work(&event->pending_task, perf_pending_task); + + mutex_init(&event->mmap_mutex); + raw_spin_lock_init(&event->addr_filters.lock); + + atomic_long_set(&event->refcount, 1); + 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(task_active_pid_ns(current)); + event->id = atomic64_inc_return(&perf_event_id); + + event->state = PERF_EVENT_STATE_INACTIVE; + + if (parent_event) + event->event_caps = parent_event->event_caps; + + if (task) { + event->attach_state = PERF_ATTACH_TASK; + /* + * XXX pmu::event_init needs to know what task to account to + * and we cannot use the ctx information because we need the + * pmu before we get a ctx. + */ + event->hw.target = get_task_struct(task); + } + + event->clock = &local_clock; + if (parent_event) + event->clock = parent_event->clock; + + if (!overflow_handler && parent_event) { + overflow_handler = parent_event->overflow_handler; + context = parent_event->overflow_handler_context; +#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING) + if (overflow_handler == bpf_overflow_handler) { + struct bpf_prog *prog = parent_event->prog; + + bpf_prog_inc(prog); + event->prog = prog; + event->orig_overflow_handler = + parent_event->orig_overflow_handler; + } +#endif + } + + if (overflow_handler) { + event->overflow_handler = overflow_handler; + event->overflow_handler_context = context; + } else if (is_write_backward(event)){ + event->overflow_handler = perf_event_output_backward; + event->overflow_handler_context = NULL; + } else { + event->overflow_handler = perf_event_output_forward; + event->overflow_handler_context = NULL; + } + + perf_event__state_init(event); + + 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_SAMPLE_READ on inherited events. + * See perf_output_read(). + */ + if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ)) + goto err_ns; + + if (!has_branch_stack(event)) + event->attr.branch_sample_type = 0; + + pmu = perf_init_event(event); + if (IS_ERR(pmu)) { + err = PTR_ERR(pmu); + goto err_ns; + } + + /* + * Disallow uncore-cgroup events, they don't make sense as the cgroup will + * be different on other CPUs in the uncore mask. + */ + if (pmu->task_ctx_nr == perf_invalid_context && cgroup_fd != -1) { + err = -EINVAL; + goto err_pmu; + } + + if (event->attr.aux_output && + !(pmu->capabilities & PERF_PMU_CAP_AUX_OUTPUT)) { + err = -EOPNOTSUPP; + goto err_pmu; + } + + if (cgroup_fd != -1) { + err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader); + if (err) + goto err_pmu; + } + + err = exclusive_event_init(event); + if (err) + goto err_pmu; + + if (has_addr_filter(event)) { + event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters, + sizeof(struct perf_addr_filter_range), + GFP_KERNEL); + if (!event->addr_filter_ranges) { + err = -ENOMEM; + goto err_per_task; + } + + /* + * Clone the parent's vma offsets: they are valid until exec() + * even if the mm is not shared with the parent. + */ + if (event->parent) { + struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); + + raw_spin_lock_irq(&ifh->lock); + memcpy(event->addr_filter_ranges, + event->parent->addr_filter_ranges, + pmu->nr_addr_filters * sizeof(struct perf_addr_filter_range)); + raw_spin_unlock_irq(&ifh->lock); + } + + /* force hw sync on the address filters */ + event->addr_filters_gen = 1; + } + + if (!event->parent) { + if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) { + err = get_callchain_buffers(attr->sample_max_stack); + if (err) + goto err_addr_filters; + } + } + + err = security_perf_event_alloc(event); + if (err) + goto err_callchain_buffer; + + /* symmetric to unaccount_event() in _free_event() */ + account_event(event); + + return event; + +err_callchain_buffer: + if (!event->parent) { + if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) + put_callchain_buffers(); + } +err_addr_filters: + kfree(event->addr_filter_ranges); + +err_per_task: + exclusive_event_destroy(event); + +err_pmu: + if (is_cgroup_event(event)) + perf_detach_cgroup(event); + if (event->destroy) + event->destroy(event); + module_put(pmu->module); +err_ns: + if (event->hw.target) + put_task_struct(event->hw.target); + call_rcu(&event->rcu_head, free_event_rcu); + + return ERR_PTR(err); +} + +static int perf_copy_attr(struct perf_event_attr __user *uattr, + struct perf_event_attr *attr) +{ + u32 size; + int ret; + + /* 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; + + /* ABI compatibility quirk: */ + if (!size) + size = PERF_ATTR_SIZE_VER0; + if (size < PERF_ATTR_SIZE_VER0 || size > PAGE_SIZE) + goto err_size; + + ret = copy_struct_from_user(attr, sizeof(*attr), uattr, size); + if (ret) { + if (ret == -E2BIG) + goto err_size; + return ret; + } + + attr->size = size; + + if (attr->__reserved_1 || attr->__reserved_2 || attr->__reserved_3) + return -EINVAL; + + if (attr->sample_type & ~(PERF_SAMPLE_MAX-1)) + return -EINVAL; + + if (attr->read_format & ~(PERF_FORMAT_MAX-1)) + return -EINVAL; + + if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) { + u64 mask = attr->branch_sample_type; + + /* only using defined bits */ + if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1)) + return -EINVAL; + + /* at least one branch bit must be set */ + if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL)) + return -EINVAL; + + /* propagate priv level, when not set for branch */ + if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) { + + /* exclude_kernel checked on syscall entry */ + if (!attr->exclude_kernel) + mask |= PERF_SAMPLE_BRANCH_KERNEL; + + if (!attr->exclude_user) + mask |= PERF_SAMPLE_BRANCH_USER; + + if (!attr->exclude_hv) + mask |= PERF_SAMPLE_BRANCH_HV; + /* + * adjust user setting (for HW filter setup) + */ + attr->branch_sample_type = mask; + } + /* privileged levels capture (kernel, hv): check permissions */ + if (mask & PERF_SAMPLE_BRANCH_PERM_PLM) { + ret = perf_allow_kernel(attr); + if (ret) + return ret; + } + } + + if (attr->sample_type & PERF_SAMPLE_REGS_USER) { + ret = perf_reg_validate(attr->sample_regs_user); + if (ret) + return ret; + } + + if (attr->sample_type & PERF_SAMPLE_STACK_USER) { + if (!arch_perf_have_user_stack_dump()) + return -ENOSYS; + + /* + * We have __u32 type for the size, but so far + * we can only use __u16 as maximum due to the + * __u16 sample size limit. + */ + if (attr->sample_stack_user >= USHRT_MAX) + return -EINVAL; + else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64))) + return -EINVAL; + } + + if (!attr->sample_max_stack) + attr->sample_max_stack = sysctl_perf_event_max_stack; + + if (attr->sample_type & PERF_SAMPLE_REGS_INTR) + ret = perf_reg_validate(attr->sample_regs_intr); + +#ifndef CONFIG_CGROUP_PERF + if (attr->sample_type & PERF_SAMPLE_CGROUP) + return -EINVAL; +#endif + if ((attr->sample_type & PERF_SAMPLE_WEIGHT) && + (attr->sample_type & PERF_SAMPLE_WEIGHT_STRUCT)) + return -EINVAL; + + if (!attr->inherit && attr->inherit_thread) + return -EINVAL; + + if (attr->remove_on_exec && attr->enable_on_exec) + return -EINVAL; + + if (attr->sigtrap && !attr->remove_on_exec) + return -EINVAL; + +out: + return ret; + +err_size: + put_user(sizeof(*attr), &uattr->size); + ret = -E2BIG; + goto out; +} + +static void mutex_lock_double(struct mutex *a, struct mutex *b) +{ + if (b < a) + swap(a, b); + + mutex_lock(a); + mutex_lock_nested(b, SINGLE_DEPTH_NESTING); +} + +static int +perf_event_set_output(struct perf_event *event, struct perf_event *output_event) +{ + struct perf_buffer *rb = NULL; + int ret = -EINVAL; + + if (!output_event) { + mutex_lock(&event->mmap_mutex); + 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 rb, it must be the same task. + */ + if (output_event->cpu == -1 && output_event->hw.target != event->hw.target) + goto out; + + /* + * Mixing clocks in the same buffer is trouble you don't need. + */ + if (output_event->clock != event->clock) + goto out; + + /* + * Either writing ring buffer from beginning or from end. + * Mixing is not allowed. + */ + if (is_write_backward(output_event) != is_write_backward(event)) + goto out; + + /* + * If both events generate aux data, they must be on the same PMU + */ + if (has_aux(event) && has_aux(output_event) && + event->pmu != output_event->pmu) + goto out; + + /* + * Hold both mmap_mutex to serialize against perf_mmap_close(). Since + * output_event is already on rb->event_list, and the list iteration + * restarts after every removal, it is guaranteed this new event is + * observed *OR* if output_event is already removed, it's guaranteed we + * observe !rb->mmap_count. + */ + mutex_lock_double(&event->mmap_mutex, &output_event->mmap_mutex); +set: + /* Can't redirect output if we've got an active mmap() */ + if (atomic_read(&event->mmap_count)) + goto unlock; + + if (output_event) { + /* get the rb we want to redirect to */ + rb = ring_buffer_get(output_event); + if (!rb) + goto unlock; + + /* did we race against perf_mmap_close() */ + if (!atomic_read(&rb->mmap_count)) { + ring_buffer_put(rb); + goto unlock; + } + } + + ring_buffer_attach(event, rb); + + ret = 0; +unlock: + mutex_unlock(&event->mmap_mutex); + if (output_event) + mutex_unlock(&output_event->mmap_mutex); + +out: + return ret; +} + +static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id) +{ + bool nmi_safe = false; + + switch (clk_id) { + case CLOCK_MONOTONIC: + event->clock = &ktime_get_mono_fast_ns; + nmi_safe = true; + break; + + case CLOCK_MONOTONIC_RAW: + event->clock = &ktime_get_raw_fast_ns; + nmi_safe = true; + break; + + case CLOCK_REALTIME: + event->clock = &ktime_get_real_ns; + break; + + case CLOCK_BOOTTIME: + event->clock = &ktime_get_boottime_ns; + break; + + case CLOCK_TAI: + event->clock = &ktime_get_clocktai_ns; + break; + + default: + return -EINVAL; + } + + if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI)) + return -EINVAL; + + return 0; +} + +/* + * Variation on perf_event_ctx_lock_nested(), except we take two context + * mutexes. + */ +static struct perf_event_context * +__perf_event_ctx_lock_double(struct perf_event *group_leader, + struct perf_event_context *ctx) +{ + struct perf_event_context *gctx; + +again: + rcu_read_lock(); + gctx = READ_ONCE(group_leader->ctx); + if (!refcount_inc_not_zero(&gctx->refcount)) { + rcu_read_unlock(); + goto again; + } + rcu_read_unlock(); + + mutex_lock_double(&gctx->mutex, &ctx->mutex); + + if (group_leader->ctx != gctx) { + mutex_unlock(&ctx->mutex); + mutex_unlock(&gctx->mutex); + put_ctx(gctx); + goto again; + } + + return gctx; +} + +static bool +perf_check_permission(struct perf_event_attr *attr, struct task_struct *task) +{ + unsigned int ptrace_mode = PTRACE_MODE_READ_REALCREDS; + bool is_capable = perfmon_capable(); + + if (attr->sigtrap) { + /* + * perf_event_attr::sigtrap sends signals to the other task. + * Require the current task to also have CAP_KILL. + */ + rcu_read_lock(); + is_capable &= ns_capable(__task_cred(task)->user_ns, CAP_KILL); + rcu_read_unlock(); + + /* + * If the required capabilities aren't available, checks for + * ptrace permissions: upgrade to ATTACH, since sending signals + * can effectively change the target task. + */ + ptrace_mode = PTRACE_MODE_ATTACH_REALCREDS; + } + + /* + * Preserve ptrace permission check for backwards compatibility. The + * ptrace check also includes checks that the current task and other + * task have matching uids, and is therefore not done here explicitly. + */ + return is_capable || ptrace_may_access(task, ptrace_mode); +} + +/** + * 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 + * @flags: perf event open flags + */ +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, *gctx; + struct file *event_file = NULL; + struct fd group = {NULL, 0}; + struct task_struct *task = NULL; + struct pmu *pmu; + int event_fd; + int move_group = 0; + int err; + int f_flags = O_RDWR; + int cgroup_fd = -1; + + /* for future expandability... */ + if (flags & ~PERF_FLAG_ALL) + return -EINVAL; + + err = perf_copy_attr(attr_uptr, &attr); + if (err) + return err; + + /* Do we allow access to perf_event_open(2) ? */ + err = security_perf_event_open(&attr, PERF_SECURITY_OPEN); + if (err) + return err; + + if (!attr.exclude_kernel) { + err = perf_allow_kernel(&attr); + if (err) + return err; + } + + if (attr.namespaces) { + if (!perfmon_capable()) + return -EACCES; + } + + if (attr.freq) { + if (attr.sample_freq > sysctl_perf_event_sample_rate) + return -EINVAL; + } else { + if (attr.sample_period & (1ULL << 63)) + return -EINVAL; + } + + /* Only privileged users can get physical addresses */ + if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR)) { + err = perf_allow_kernel(&attr); + if (err) + return err; + } + + /* REGS_INTR can leak data, lockdown must prevent this */ + if (attr.sample_type & PERF_SAMPLE_REGS_INTR) { + err = security_locked_down(LOCKDOWN_PERF); + if (err) + return err; + } + + /* + * 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; + + if (flags & PERF_FLAG_FD_CLOEXEC) + f_flags |= O_CLOEXEC; + + event_fd = get_unused_fd_flags(f_flags); + if (event_fd < 0) + return event_fd; + + if (group_fd != -1) { + err = perf_fget_light(group_fd, &group); + if (err) + goto err_fd; + group_leader = group.file->private_data; + 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; + } + } + + if (task && group_leader && + group_leader->attr.inherit != attr.inherit) { + err = -EINVAL; + goto err_task; + } + + if (flags & PERF_FLAG_PID_CGROUP) + cgroup_fd = pid; + + event = perf_event_alloc(&attr, cpu, task, group_leader, NULL, + NULL, NULL, cgroup_fd); + if (IS_ERR(event)) { + err = PTR_ERR(event); + goto err_task; + } + + if (is_sampling_event(event)) { + if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) { + err = -EOPNOTSUPP; + goto err_alloc; + } + } + + /* + * Special case software events and allow them to be part of + * any hardware group. + */ + pmu = event->pmu; + + if (attr.use_clockid) { + err = perf_event_set_clock(event, attr.clockid); + if (err) + goto err_alloc; + } + + if (pmu->task_ctx_nr == perf_sw_context) + event->event_caps |= PERF_EV_CAP_SOFTWARE; + + if (group_leader) { + if (is_software_event(event) && + !in_software_context(group_leader)) { + /* + * If the event is a sw event, but the group_leader + * is on hw context. + * + * Allow the addition of software events to hw + * groups, this is safe because software events + * never fail to schedule. + */ + pmu = group_leader->ctx->pmu; + } else if (!is_software_event(event) && + is_software_event(group_leader) && + (group_leader->group_caps & PERF_EV_CAP_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, event); + if (IS_ERR(ctx)) { + err = PTR_ERR(ctx); + goto err_alloc; + } + + /* + * 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; + + /* All events in a group should have the same clock */ + if (group_leader->clock != event->clock) + goto err_context; + + /* + * Make sure we're both events for the same CPU; + * grouping events for different CPUs is broken; since + * you can never concurrently schedule them anyhow. + */ + if (group_leader->cpu != event->cpu) + goto err_context; + + /* + * Make sure we're both on the same task, or both + * per-CPU events. + */ + if (group_leader->ctx->task != ctx->task) + goto err_context; + + /* + * Do not allow to attach to a group in a different task + * or CPU context. If we're moving SW events, we'll fix + * this up later, so allow that. + * + * Racy, not holding group_leader->ctx->mutex, see comment with + * perf_event_ctx_lock(). + */ + if (!move_group && 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, + f_flags); + if (IS_ERR(event_file)) { + err = PTR_ERR(event_file); + event_file = NULL; + goto err_context; + } + + if (task) { + err = down_read_interruptible(&task->signal->exec_update_lock); + if (err) + goto err_file; + + /* + * We must hold exec_update_lock across this and any potential + * perf_install_in_context() call for this new event to + * serialize against exec() altering our credentials (and the + * perf_event_exit_task() that could imply). + */ + err = -EACCES; + if (!perf_check_permission(&attr, task)) + goto err_cred; + } + + if (move_group) { + gctx = __perf_event_ctx_lock_double(group_leader, ctx); + + if (gctx->task == TASK_TOMBSTONE) { + err = -ESRCH; + goto err_locked; + } + + /* + * Check if we raced against another sys_perf_event_open() call + * moving the software group underneath us. + */ + if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) { + /* + * If someone moved the group out from under us, check + * if this new event wound up on the same ctx, if so + * its the regular !move_group case, otherwise fail. + */ + if (gctx != ctx) { + err = -EINVAL; + goto err_locked; + } else { + perf_event_ctx_unlock(group_leader, gctx); + move_group = 0; + goto not_move_group; + } + } + + /* + * Failure to create exclusive events returns -EBUSY. + */ + err = -EBUSY; + if (!exclusive_event_installable(group_leader, ctx)) + goto err_locked; + + for_each_sibling_event(sibling, group_leader) { + if (!exclusive_event_installable(sibling, ctx)) + goto err_locked; + } + } else { + mutex_lock(&ctx->mutex); + + /* + * Now that we hold ctx->lock, (re)validate group_leader->ctx == ctx, + * see the group_leader && !move_group test earlier. + */ + if (group_leader && group_leader->ctx != ctx) { + err = -EINVAL; + goto err_locked; + } + } +not_move_group: + + if (ctx->task == TASK_TOMBSTONE) { + err = -ESRCH; + goto err_locked; + } + + if (!perf_event_validate_size(event)) { + err = -E2BIG; + goto err_locked; + } + + if (!task) { + /* + * Check if the @cpu we're creating an event for is online. + * + * We use the perf_cpu_context::ctx::mutex to serialize against + * the hotplug notifiers. See perf_event_{init,exit}_cpu(). + */ + struct perf_cpu_context *cpuctx = + container_of(ctx, struct perf_cpu_context, ctx); + + if (!cpuctx->online) { + err = -ENODEV; + goto err_locked; + } + } + + if (perf_need_aux_event(event) && !perf_get_aux_event(event, group_leader)) { + err = -EINVAL; + goto err_locked; + } + + /* + * Must be under the same ctx::mutex as perf_install_in_context(), + * because we need to serialize with concurrent event creation. + */ + if (!exclusive_event_installable(event, ctx)) { + err = -EBUSY; + goto err_locked; + } + + WARN_ON_ONCE(ctx->parent_ctx); + + /* + * This is the point on no return; we cannot fail hereafter. This is + * where we start modifying current state. + */ + + if (move_group) { + /* + * See perf_event_ctx_lock() for comments on the details + * of swizzling perf_event::ctx. + */ + perf_remove_from_context(group_leader, 0); + put_ctx(gctx); + + for_each_sibling_event(sibling, group_leader) { + perf_remove_from_context(sibling, 0); + put_ctx(gctx); + } + + /* + * Wait for everybody to stop referencing the events through + * the old lists, before installing it on new lists. + */ + synchronize_rcu(); + + /* + * Install the group siblings before the group leader. + * + * Because a group leader will try and install the entire group + * (through the sibling list, which is still in-tact), we can + * end up with siblings installed in the wrong context. + * + * By installing siblings first we NO-OP because they're not + * reachable through the group lists. + */ + for_each_sibling_event(sibling, group_leader) { + perf_event__state_init(sibling); + perf_install_in_context(ctx, sibling, sibling->cpu); + get_ctx(ctx); + } + + /* + * Removing from the context ends up with disabled + * event. What we want here is event in the initial + * startup state, ready to be add into new context. + */ + perf_event__state_init(group_leader); + perf_install_in_context(ctx, group_leader, group_leader->cpu); + get_ctx(ctx); + } + + /* + * Precalculate sample_data sizes; do while holding ctx::mutex such + * that we're serialized against further additions and before + * perf_install_in_context() which is the point the event is active and + * can use these values. + */ + perf_event__header_size(event); + perf_event__id_header_size(event); + + event->owner = current; + + perf_install_in_context(ctx, event, event->cpu); + perf_unpin_context(ctx); + + if (move_group) + perf_event_ctx_unlock(group_leader, gctx); + mutex_unlock(&ctx->mutex); + + if (task) { + up_read(&task->signal->exec_update_lock); + put_task_struct(task); + } + + mutex_lock(¤t->perf_event_mutex); + list_add_tail(&event->owner_entry, ¤t->perf_event_list); + mutex_unlock(¤t->perf_event_mutex); + + /* + * 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(). + */ + fdput(group); + fd_install(event_fd, event_file); + return event_fd; + +err_locked: + if (move_group) + perf_event_ctx_unlock(group_leader, gctx); + mutex_unlock(&ctx->mutex); +err_cred: + if (task) + up_read(&task->signal->exec_update_lock); +err_file: + fput(event_file); +err_context: + perf_unpin_context(ctx); + put_ctx(ctx); +err_alloc: + /* + * If event_file is set, the fput() above will have called ->release() + * and that will take care of freeing the event. + */ + if (!event_file) + free_event(event); +err_task: + if (task) + put_task_struct(task); +err_group_fd: + fdput(group); +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) + * @overflow_handler: callback to trigger when we hit the event + * @context: context data could be used in overflow_handler callback + */ +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, + void *context) +{ + struct perf_event_context *ctx; + struct perf_event *event; + int err; + + /* + * Grouping is not supported for kernel events, neither is 'AUX', + * make sure the caller's intentions are adjusted. + */ + if (attr->aux_output) + return ERR_PTR(-EINVAL); + + event = perf_event_alloc(attr, cpu, task, NULL, NULL, + overflow_handler, context, -1); + if (IS_ERR(event)) { + err = PTR_ERR(event); + goto err; + } + + /* Mark owner so we could distinguish it from user events. */ + event->owner = TASK_TOMBSTONE; + + /* + * Get the target context (task or percpu): + */ + ctx = find_get_context(event->pmu, task, event); + if (IS_ERR(ctx)) { + err = PTR_ERR(ctx); + goto err_free; + } + + WARN_ON_ONCE(ctx->parent_ctx); + mutex_lock(&ctx->mutex); + if (ctx->task == TASK_TOMBSTONE) { + err = -ESRCH; + goto err_unlock; + } + + if (!task) { + /* + * Check if the @cpu we're creating an event for is online. + * + * We use the perf_cpu_context::ctx::mutex to serialize against + * the hotplug notifiers. See perf_event_{init,exit}_cpu(). + */ + struct perf_cpu_context *cpuctx = + container_of(ctx, struct perf_cpu_context, ctx); + if (!cpuctx->online) { + err = -ENODEV; + goto err_unlock; + } + } + + if (!exclusive_event_installable(event, ctx)) { + err = -EBUSY; + goto err_unlock; + } + + perf_install_in_context(ctx, event, event->cpu); + perf_unpin_context(ctx); + mutex_unlock(&ctx->mutex); + + return event; + +err_unlock: + mutex_unlock(&ctx->mutex); + perf_unpin_context(ctx); + put_ctx(ctx); +err_free: + free_event(event); +err: + return ERR_PTR(err); +} +EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter); + +void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu) +{ + struct perf_event_context *src_ctx; + struct perf_event_context *dst_ctx; + struct perf_event *event, *tmp; + LIST_HEAD(events); + + src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx; + dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx; + + /* + * See perf_event_ctx_lock() for comments on the details + * of swizzling perf_event::ctx. + */ + mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex); + list_for_each_entry_safe(event, tmp, &src_ctx->event_list, + event_entry) { + perf_remove_from_context(event, 0); + unaccount_event_cpu(event, src_cpu); + put_ctx(src_ctx); + list_add(&event->migrate_entry, &events); + } + + /* + * Wait for the events to quiesce before re-instating them. + */ + synchronize_rcu(); + + /* + * Re-instate events in 2 passes. + * + * Skip over group leaders and only install siblings on this first + * pass, siblings will not get enabled without a leader, however a + * leader will enable its siblings, even if those are still on the old + * context. + */ + list_for_each_entry_safe(event, tmp, &events, migrate_entry) { + if (event->group_leader == event) + continue; + + list_del(&event->migrate_entry); + if (event->state >= PERF_EVENT_STATE_OFF) + event->state = PERF_EVENT_STATE_INACTIVE; + account_event_cpu(event, dst_cpu); + perf_install_in_context(dst_ctx, event, dst_cpu); + get_ctx(dst_ctx); + } + + /* + * Once all the siblings are setup properly, install the group leaders + * to make it go. + */ + list_for_each_entry_safe(event, tmp, &events, migrate_entry) { + list_del(&event->migrate_entry); + if (event->state >= PERF_EVENT_STATE_OFF) + event->state = PERF_EVENT_STATE_INACTIVE; + account_event_cpu(event, dst_cpu); + perf_install_in_context(dst_ctx, event, dst_cpu); + get_ctx(dst_ctx); + } + mutex_unlock(&dst_ctx->mutex); + mutex_unlock(&src_ctx->mutex); +} +EXPORT_SYMBOL_GPL(perf_pmu_migrate_context); + +static void sync_child_event(struct perf_event *child_event) +{ + struct perf_event *parent_event = child_event->parent; + u64 child_val; + + if (child_event->attr.inherit_stat) { + struct task_struct *task = child_event->ctx->task; + + if (task && task != TASK_TOMBSTONE) + perf_event_read_event(child_event, task); + } + + 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); +} + +static void +perf_event_exit_event(struct perf_event *event, struct perf_event_context *ctx) +{ + struct perf_event *parent_event = event->parent; + unsigned long detach_flags = 0; + + if (parent_event) { + /* + * Do not destroy the 'original' grouping; because of the + * context switch optimization the original events could've + * ended up in a random child task. + * + * If we were to destroy the original group, all group related + * operations would cease to function properly after this + * random child dies. + * + * Do destroy all inherited groups, we don't care about those + * and being thorough is better. + */ + detach_flags = DETACH_GROUP | DETACH_CHILD; + mutex_lock(&parent_event->child_mutex); + } + + perf_remove_from_context(event, detach_flags); + + raw_spin_lock_irq(&ctx->lock); + if (event->state > PERF_EVENT_STATE_EXIT) + perf_event_set_state(event, PERF_EVENT_STATE_EXIT); + raw_spin_unlock_irq(&ctx->lock); + + /* + * Child events can be freed. + */ + if (parent_event) { + mutex_unlock(&parent_event->child_mutex); + /* + * Kick perf_poll() for is_event_hup(); + */ + perf_event_wakeup(parent_event); + free_event(event); + put_event(parent_event); + return; + } + + /* + * Parent events are governed by their filedesc, retain them. + */ + perf_event_wakeup(event); +} + +static void perf_event_exit_task_context(struct task_struct *child, int ctxn) +{ + struct perf_event_context *child_ctx, *clone_ctx = NULL; + struct perf_event *child_event, *next; + + WARN_ON_ONCE(child != current); + + child_ctx = perf_pin_task_context(child, ctxn); + if (!child_ctx) + return; + + /* + * In order to reduce the amount of tricky in ctx tear-down, we hold + * ctx::mutex over the entire thing. This serializes against almost + * everything that wants to access the ctx. + * + * The exception is sys_perf_event_open() / + * perf_event_create_kernel_count() which does find_get_context() + * without ctx::mutex (it cannot because of the move_group double mutex + * lock thing). See the comments in perf_install_in_context(). + */ + mutex_lock(&child_ctx->mutex); + + /* + * In a single ctx::lock section, de-schedule the events and detach the + * context from the task such that we cannot ever get it scheduled back + * in. + */ + raw_spin_lock_irq(&child_ctx->lock); + task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL); + + /* + * Now that the context is inactive, destroy the task <-> ctx relation + * and mark the context dead. + */ + RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL); + put_ctx(child_ctx); /* cannot be last */ + WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE); + put_task_struct(current); /* cannot be last */ + + clone_ctx = unclone_ctx(child_ctx); + raw_spin_unlock_irq(&child_ctx->lock); + + if (clone_ctx) + put_ctx(clone_ctx); + + /* + * 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); + + list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry) + perf_event_exit_event(child_event, child_ctx); + + mutex_unlock(&child_ctx->mutex); + + put_ctx(child_ctx); +} + +/* + * When a child task exits, feed back event values to parent events. + * + * Can be called with exec_update_lock held when called from + * setup_new_exec(). + */ +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_store_release(&event->owner, NULL); + } + mutex_unlock(&child->perf_event_mutex); + + for_each_task_context_nr(ctxn) + perf_event_exit_task_context(child, ctxn); + + /* + * The perf_event_exit_task_context calls perf_event_task + * with child's task_ctx, which generates EXIT events for + * child contexts and sets child->perf_event_ctxp[] to NULL. + * At this point we need to send EXIT events to cpu contexts. + */ + perf_event_task(child, NULL, 0); +} + +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); + + put_event(parent); + + raw_spin_lock_irq(&ctx->lock); + perf_group_detach(event); + list_del_event(event, ctx); + raw_spin_unlock_irq(&ctx->lock); + free_event(event); +} + +/* + * Free a context as created by inheritance by perf_event_init_task() below, + * used by fork() in case of fail. + * + * Even though the task has never lived, the context and events have been + * exposed through the child_list, so we must take care tearing it all down. + */ +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); + raw_spin_lock_irq(&ctx->lock); + /* + * Destroy the task <-> ctx relation and mark the context dead. + * + * This is important because even though the task hasn't been + * exposed yet the context has been (through child_list). + */ + RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL); + WRITE_ONCE(ctx->task, TASK_TOMBSTONE); + put_task_struct(task); /* cannot be last */ + raw_spin_unlock_irq(&ctx->lock); + + list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry) + perf_free_event(event, ctx); + + mutex_unlock(&ctx->mutex); + + /* + * perf_event_release_kernel() could've stolen some of our + * child events and still have them on its free_list. In that + * case we must wait for these events to have been freed (in + * particular all their references to this task must've been + * dropped). + * + * Without this copy_process() will unconditionally free this + * task (irrespective of its reference count) and + * _free_event()'s put_task_struct(event->hw.target) will be a + * use-after-free. + * + * Wait for all events to drop their context reference. + */ + wait_var_event(&ctx->refcount, refcount_read(&ctx->refcount) == 1); + put_ctx(ctx); /* must be last */ + } +} + +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]); +} + +struct file *perf_event_get(unsigned int fd) +{ + struct file *file = fget(fd); + if (!file) + return ERR_PTR(-EBADF); + + if (file->f_op != &perf_fops) { + fput(file); + return ERR_PTR(-EBADF); + } + + return file; +} + +const struct perf_event *perf_get_event(struct file *file) +{ + if (file->f_op != &perf_fops) + return ERR_PTR(-EINVAL); + + return file->private_data; +} + +const struct perf_event_attr *perf_event_attrs(struct perf_event *event) +{ + if (!event) + return ERR_PTR(-EINVAL); + + return &event->attr; +} + +/* + * Inherit an event from parent task to child task. + * + * Returns: + * - valid pointer on success + * - NULL for orphaned events + * - IS_ERR() on error + */ +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) +{ + enum perf_event_state parent_state = parent_event->state; + 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, NULL, -1); + if (IS_ERR(child_event)) + return child_event; + + + if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) && + !child_ctx->task_ctx_data) { + struct pmu *pmu = child_event->pmu; + + child_ctx->task_ctx_data = alloc_task_ctx_data(pmu); + if (!child_ctx->task_ctx_data) { + free_event(child_event); + return ERR_PTR(-ENOMEM); + } + } + + /* + * is_orphaned_event() and list_add_tail(&parent_event->child_list) + * must be under the same lock in order to serialize against + * perf_event_release_kernel(), such that either we must observe + * is_orphaned_event() or they will observe us on the child_list. + */ + mutex_lock(&parent_event->child_mutex); + if (is_orphaned_event(parent_event) || + !atomic_long_inc_not_zero(&parent_event->refcount)) { + mutex_unlock(&parent_event->child_mutex); + /* task_ctx_data is freed with child_ctx */ + free_event(child_event); + return NULL; + } + + 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_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; + child_event->overflow_handler_context + = parent_event->overflow_handler_context; + + /* + * 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); + child_event->attach_state |= PERF_ATTACH_CHILD; + raw_spin_unlock_irqrestore(&child_ctx->lock, flags); + + /* + * Link this into the parent event's child list + */ + list_add_tail(&child_event->child_list, &parent_event->child_list); + mutex_unlock(&parent_event->child_mutex); + + return child_event; +} + +/* + * Inherits an event group. + * + * This will quietly suppress orphaned events; !inherit_event() is not an error. + * This matches with perf_event_release_kernel() removing all child events. + * + * Returns: + * - 0 on success + * - <0 on error + */ +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); + /* + * @leader can be NULL here because of is_orphaned_event(). In this + * case inherit_event() will create individual events, similar to what + * perf_group_detach() would do anyway. + */ + for_each_sibling_event(sub, parent_event) { + child_ctr = inherit_event(sub, parent, parent_ctx, + child, leader, child_ctx); + if (IS_ERR(child_ctr)) + return PTR_ERR(child_ctr); + + if (sub->aux_event == parent_event && child_ctr && + !perf_get_aux_event(child_ctr, leader)) + return -EINVAL; + } + if (leader) + leader->group_generation = parent_event->group_generation; + return 0; +} + +/* + * Creates the child task context and tries to inherit the event-group. + * + * Clears @inherited_all on !attr.inherited or error. Note that we'll leave + * inherited_all set when we 'fail' to inherit an orphaned event; this is + * consistent with perf_event_release_kernel() removing all child events. + * + * Returns: + * - 0 on success + * - <0 on error + */ +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, + u64 clone_flags, int *inherited_all) +{ + int ret; + struct perf_event_context *child_ctx; + + if (!event->attr.inherit || + (event->attr.inherit_thread && !(clone_flags & CLONE_THREAD)) || + /* Do not inherit if sigtrap and signal handlers were cleared. */ + (event->attr.sigtrap && (clone_flags & CLONE_CLEAR_SIGHAND))) { + *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(parent_ctx->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 + */ +static int perf_event_init_context(struct task_struct *child, int ctxn, + u64 clone_flags) +{ + 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); + if (!parent_ctx) + return 0; + + /* + * 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: + */ + perf_event_groups_for_each(event, &parent_ctx->pinned_groups) { + ret = inherit_task_group(event, parent, parent_ctx, + child, ctxn, clone_flags, + &inherited_all); + if (ret) + goto out_unlock; + } + + /* + * 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); + + perf_event_groups_for_each(event, &parent_ctx->flexible_groups) { + ret = inherit_task_group(event, parent, parent_ctx, + child, ctxn, clone_flags, + &inherited_all); + if (ret) + goto out_unlock; + } + + 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); +out_unlock: + 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, u64 clone_flags) +{ + 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, clone_flags); + if (ret) { + perf_event_free_task(child); + return ret; + } + } + + return 0; +} + +static void __init perf_event_init_all_cpus(void) +{ + struct swevent_htable *swhash; + int cpu; + + zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL); + + for_each_possible_cpu(cpu) { + swhash = &per_cpu(swevent_htable, cpu); + mutex_init(&swhash->hlist_mutex); + INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu)); + + INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu)); + raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu)); + +#ifdef CONFIG_CGROUP_PERF + INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu)); +#endif + INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu)); + } +} + +static void perf_swevent_init_cpu(unsigned int cpu) +{ + struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); + + mutex_lock(&swhash->hlist_mutex); + if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) { + 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_CORE +static void __perf_event_exit_context(void *__info) +{ + struct perf_event_context *ctx = __info; + struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); + struct perf_event *event; + + raw_spin_lock(&ctx->lock); + ctx_sched_out(ctx, cpuctx, EVENT_TIME); + list_for_each_entry(event, &ctx->event_list, event_entry) + __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP); + raw_spin_unlock(&ctx->lock); +} + +static void perf_event_exit_cpu_context(int cpu) +{ + struct perf_cpu_context *cpuctx; + struct perf_event_context *ctx; + struct pmu *pmu; + + mutex_lock(&pmus_lock); + list_for_each_entry(pmu, &pmus, entry) { + cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); + ctx = &cpuctx->ctx; + + mutex_lock(&ctx->mutex); + smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1); + cpuctx->online = 0; + mutex_unlock(&ctx->mutex); + } + cpumask_clear_cpu(cpu, perf_online_mask); + mutex_unlock(&pmus_lock); +} +#else + +static void perf_event_exit_cpu_context(int cpu) { } + +#endif + +int perf_event_init_cpu(unsigned int cpu) +{ + struct perf_cpu_context *cpuctx; + struct perf_event_context *ctx; + struct pmu *pmu; + + perf_swevent_init_cpu(cpu); + + mutex_lock(&pmus_lock); + cpumask_set_cpu(cpu, perf_online_mask); + list_for_each_entry(pmu, &pmus, entry) { + cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); + ctx = &cpuctx->ctx; + + mutex_lock(&ctx->mutex); + cpuctx->online = 1; + mutex_unlock(&ctx->mutex); + } + mutex_unlock(&pmus_lock); + + return 0; +} + +int perf_event_exit_cpu(unsigned int cpu) +{ + perf_event_exit_cpu_context(cpu); + return 0; +} + +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, +}; + +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_event_init_cpu(smp_processor_id()); + register_reboot_notifier(&perf_reboot_notifier); + + ret = init_hw_breakpoint(); + WARN(ret, "hw_breakpoint initialization failed with: %d", ret); + + perf_event_cache = KMEM_CACHE(perf_event, SLAB_PANIC); + + /* + * Build time assertion that we keep the data_head at the intended + * location. IOW, validation we got the __reserved[] size right. + */ + BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head)) + != 1024); +} + +ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr, + char *page) +{ + struct perf_pmu_events_attr *pmu_attr = + container_of(attr, struct perf_pmu_events_attr, attr); + + if (pmu_attr->event_str) + return sprintf(page, "%s\n", pmu_attr->event_str); + + return 0; +} +EXPORT_SYMBOL_GPL(perf_event_sysfs_show); + +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_css_alloc(struct cgroup_subsys_state *parent_css) +{ + 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_css_free(struct cgroup_subsys_state *css) +{ + struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css); + + free_percpu(jc->info); + kfree(jc); +} + +static int perf_cgroup_css_online(struct cgroup_subsys_state *css) +{ + perf_event_cgroup(css->cgroup); + return 0; +} + +static int __perf_cgroup_move(void *info) +{ + struct task_struct *task = info; + rcu_read_lock(); + perf_cgroup_switch(task); + rcu_read_unlock(); + return 0; +} + +static void perf_cgroup_attach(struct cgroup_taskset *tset) +{ + struct task_struct *task; + struct cgroup_subsys_state *css; + + cgroup_taskset_for_each(task, css, tset) + task_function_call(task, __perf_cgroup_move, task); +} + +struct cgroup_subsys perf_event_cgrp_subsys = { + .css_alloc = perf_cgroup_css_alloc, + .css_free = perf_cgroup_css_free, + .css_online = perf_cgroup_css_online, + .attach = perf_cgroup_attach, + /* + * Implicitly enable on dfl hierarchy so that perf events can + * always be filtered by cgroup2 path as long as perf_event + * controller is not mounted on a legacy hierarchy. + */ + .implicit_on_dfl = true, + .threaded = true, +}; +#endif /* CONFIG_CGROUP_PERF */ + +DEFINE_STATIC_CALL_RET0(perf_snapshot_branch_stack, perf_snapshot_branch_stack_t); |