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![Soeren Sandmann](/assets/img/avatar_default.png)
Getting samples for the idle task is often not interesting, so don't generate them when exclude_idle is set for the event in question. Signed-off-by: Søren Sandmann Pedersen <sandmann@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <ye8pr8fmlq7.fsf@camel16.daimi.au.dk> Signed-off-by: Ingo Molnar <mingo@elte.hu>
5130 lines
116 KiB
C
5130 lines
116 KiB
C
/*
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* Performance events core code:
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*
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* Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
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* Copyright (C) 2008-2009 Red Hat, Inc., Ingo Molnar
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* Copyright (C) 2008-2009 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
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* Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
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*
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* For licensing details see kernel-base/COPYING
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*/
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#include <linux/fs.h>
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#include <linux/mm.h>
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#include <linux/cpu.h>
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#include <linux/smp.h>
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#include <linux/file.h>
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#include <linux/poll.h>
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#include <linux/sysfs.h>
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#include <linux/dcache.h>
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#include <linux/percpu.h>
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#include <linux/ptrace.h>
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#include <linux/vmstat.h>
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#include <linux/vmalloc.h>
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#include <linux/hardirq.h>
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#include <linux/rculist.h>
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#include <linux/uaccess.h>
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#include <linux/syscalls.h>
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#include <linux/anon_inodes.h>
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#include <linux/kernel_stat.h>
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#include <linux/perf_event.h>
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#include <asm/irq_regs.h>
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/*
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* Each CPU has a list of per CPU events:
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*/
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DEFINE_PER_CPU(struct perf_cpu_context, perf_cpu_context);
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int perf_max_events __read_mostly = 1;
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static int perf_reserved_percpu __read_mostly;
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static int perf_overcommit __read_mostly = 1;
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static atomic_t nr_events __read_mostly;
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static atomic_t nr_mmap_events __read_mostly;
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static atomic_t nr_comm_events __read_mostly;
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static atomic_t nr_task_events __read_mostly;
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/*
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* perf event paranoia level:
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* -1 - not paranoid at all
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* 0 - disallow raw tracepoint access for unpriv
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* 1 - disallow cpu events for unpriv
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* 2 - disallow kernel profiling for unpriv
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*/
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int sysctl_perf_event_paranoid __read_mostly = 1;
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static inline bool perf_paranoid_tracepoint_raw(void)
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{
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return sysctl_perf_event_paranoid > -1;
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}
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static inline bool perf_paranoid_cpu(void)
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{
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return sysctl_perf_event_paranoid > 0;
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}
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static inline bool perf_paranoid_kernel(void)
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{
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return sysctl_perf_event_paranoid > 1;
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}
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int sysctl_perf_event_mlock __read_mostly = 512; /* 'free' kb per user */
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/*
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* max perf event sample rate
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*/
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int sysctl_perf_event_sample_rate __read_mostly = 100000;
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static atomic64_t perf_event_id;
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/*
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* Lock for (sysadmin-configurable) event reservations:
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*/
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static DEFINE_SPINLOCK(perf_resource_lock);
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/*
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* Architecture provided APIs - weak aliases:
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*/
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extern __weak const struct pmu *hw_perf_event_init(struct perf_event *event)
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{
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return NULL;
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}
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void __weak hw_perf_disable(void) { barrier(); }
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void __weak hw_perf_enable(void) { barrier(); }
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void __weak hw_perf_event_setup(int cpu) { barrier(); }
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void __weak hw_perf_event_setup_online(int cpu) { barrier(); }
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int __weak
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hw_perf_group_sched_in(struct perf_event *group_leader,
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struct perf_cpu_context *cpuctx,
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struct perf_event_context *ctx, int cpu)
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{
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return 0;
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}
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void __weak perf_event_print_debug(void) { }
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static DEFINE_PER_CPU(int, perf_disable_count);
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void __perf_disable(void)
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{
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__get_cpu_var(perf_disable_count)++;
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}
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bool __perf_enable(void)
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{
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return !--__get_cpu_var(perf_disable_count);
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}
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void perf_disable(void)
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{
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__perf_disable();
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hw_perf_disable();
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}
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void perf_enable(void)
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{
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if (__perf_enable())
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hw_perf_enable();
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}
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static void get_ctx(struct perf_event_context *ctx)
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{
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WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
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}
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static void free_ctx(struct rcu_head *head)
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{
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struct perf_event_context *ctx;
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ctx = container_of(head, struct perf_event_context, rcu_head);
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kfree(ctx);
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}
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static void put_ctx(struct perf_event_context *ctx)
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{
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if (atomic_dec_and_test(&ctx->refcount)) {
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if (ctx->parent_ctx)
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put_ctx(ctx->parent_ctx);
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if (ctx->task)
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put_task_struct(ctx->task);
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call_rcu(&ctx->rcu_head, free_ctx);
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}
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}
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static void unclone_ctx(struct perf_event_context *ctx)
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{
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if (ctx->parent_ctx) {
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put_ctx(ctx->parent_ctx);
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ctx->parent_ctx = NULL;
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}
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}
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/*
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* If we inherit events we want to return the parent event id
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* to userspace.
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*/
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static u64 primary_event_id(struct perf_event *event)
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{
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u64 id = event->id;
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if (event->parent)
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id = event->parent->id;
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return id;
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}
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/*
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* Get the perf_event_context for a task and lock it.
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* This has to cope with with the fact that until it is locked,
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* the context could get moved to another task.
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*/
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static struct perf_event_context *
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perf_lock_task_context(struct task_struct *task, unsigned long *flags)
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{
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struct perf_event_context *ctx;
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rcu_read_lock();
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retry:
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ctx = rcu_dereference(task->perf_event_ctxp);
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if (ctx) {
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/*
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* If this context is a clone of another, it might
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* get swapped for another underneath us by
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* perf_event_task_sched_out, though the
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* rcu_read_lock() protects us from any context
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* getting freed. Lock the context and check if it
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* got swapped before we could get the lock, and retry
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* if so. If we locked the right context, then it
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* can't get swapped on us any more.
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*/
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spin_lock_irqsave(&ctx->lock, *flags);
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if (ctx != rcu_dereference(task->perf_event_ctxp)) {
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spin_unlock_irqrestore(&ctx->lock, *flags);
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goto retry;
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}
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if (!atomic_inc_not_zero(&ctx->refcount)) {
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spin_unlock_irqrestore(&ctx->lock, *flags);
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ctx = NULL;
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}
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}
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rcu_read_unlock();
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return ctx;
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}
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/*
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* Get the context for a task and increment its pin_count so it
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* can't get swapped to another task. This also increments its
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* reference count so that the context can't get freed.
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*/
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static struct perf_event_context *perf_pin_task_context(struct task_struct *task)
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{
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struct perf_event_context *ctx;
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unsigned long flags;
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ctx = perf_lock_task_context(task, &flags);
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if (ctx) {
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++ctx->pin_count;
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spin_unlock_irqrestore(&ctx->lock, flags);
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}
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return ctx;
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}
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static void perf_unpin_context(struct perf_event_context *ctx)
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{
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unsigned long flags;
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spin_lock_irqsave(&ctx->lock, flags);
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--ctx->pin_count;
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spin_unlock_irqrestore(&ctx->lock, flags);
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put_ctx(ctx);
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}
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/*
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* Add a event from the lists for its context.
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* Must be called with ctx->mutex and ctx->lock held.
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*/
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static void
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list_add_event(struct perf_event *event, struct perf_event_context *ctx)
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{
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struct perf_event *group_leader = event->group_leader;
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/*
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* Depending on whether it is a standalone or sibling event,
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* add it straight to the context's event list, or to the group
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* leader's sibling list:
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*/
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if (group_leader == event)
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list_add_tail(&event->group_entry, &ctx->group_list);
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else {
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list_add_tail(&event->group_entry, &group_leader->sibling_list);
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group_leader->nr_siblings++;
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}
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list_add_rcu(&event->event_entry, &ctx->event_list);
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ctx->nr_events++;
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if (event->attr.inherit_stat)
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ctx->nr_stat++;
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}
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/*
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* Remove a event from the lists for its context.
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* Must be called with ctx->mutex and ctx->lock held.
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*/
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static void
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list_del_event(struct perf_event *event, struct perf_event_context *ctx)
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{
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struct perf_event *sibling, *tmp;
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if (list_empty(&event->group_entry))
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return;
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ctx->nr_events--;
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if (event->attr.inherit_stat)
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ctx->nr_stat--;
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list_del_init(&event->group_entry);
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list_del_rcu(&event->event_entry);
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if (event->group_leader != event)
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event->group_leader->nr_siblings--;
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/*
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* If this was a group event with sibling events then
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* upgrade the siblings to singleton events by adding them
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* to the context list directly:
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*/
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list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
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list_move_tail(&sibling->group_entry, &ctx->group_list);
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sibling->group_leader = sibling;
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}
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}
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static void
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event_sched_out(struct perf_event *event,
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struct perf_cpu_context *cpuctx,
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struct perf_event_context *ctx)
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{
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if (event->state != PERF_EVENT_STATE_ACTIVE)
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return;
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event->state = PERF_EVENT_STATE_INACTIVE;
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if (event->pending_disable) {
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event->pending_disable = 0;
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event->state = PERF_EVENT_STATE_OFF;
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}
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event->tstamp_stopped = ctx->time;
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event->pmu->disable(event);
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event->oncpu = -1;
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if (!is_software_event(event))
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cpuctx->active_oncpu--;
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ctx->nr_active--;
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if (event->attr.exclusive || !cpuctx->active_oncpu)
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cpuctx->exclusive = 0;
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}
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static void
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group_sched_out(struct perf_event *group_event,
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struct perf_cpu_context *cpuctx,
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struct perf_event_context *ctx)
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{
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struct perf_event *event;
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if (group_event->state != PERF_EVENT_STATE_ACTIVE)
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return;
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event_sched_out(group_event, cpuctx, ctx);
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/*
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* Schedule out siblings (if any):
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*/
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list_for_each_entry(event, &group_event->sibling_list, group_entry)
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event_sched_out(event, cpuctx, ctx);
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if (group_event->attr.exclusive)
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cpuctx->exclusive = 0;
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}
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/*
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* Cross CPU call to remove a performance event
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*
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* We disable the event on the hardware level first. After that we
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* remove it from the context list.
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*/
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static void __perf_event_remove_from_context(void *info)
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{
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struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
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struct perf_event *event = info;
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struct perf_event_context *ctx = event->ctx;
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/*
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* If this is a task context, we need to check whether it is
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* the current task context of this cpu. If not it has been
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* scheduled out before the smp call arrived.
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*/
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if (ctx->task && cpuctx->task_ctx != ctx)
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return;
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spin_lock(&ctx->lock);
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/*
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* Protect the list operation against NMI by disabling the
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* events on a global level.
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*/
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perf_disable();
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event_sched_out(event, cpuctx, ctx);
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list_del_event(event, ctx);
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if (!ctx->task) {
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/*
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* Allow more per task events with respect to the
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* reservation:
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*/
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cpuctx->max_pertask =
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min(perf_max_events - ctx->nr_events,
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perf_max_events - perf_reserved_percpu);
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}
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perf_enable();
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spin_unlock(&ctx->lock);
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}
|
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|
|
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/*
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* Remove the event from a task's (or a CPU's) list of events.
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*
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* Must be called with ctx->mutex held.
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*
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* CPU events are removed with a smp call. For task events we only
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* call when the task is on a CPU.
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*
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* If event->ctx is a cloned context, callers must make sure that
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* every task struct that event->ctx->task could possibly point to
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* remains valid. This is OK when called from perf_release since
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* that only calls us on the top-level context, which can't be a clone.
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* When called from perf_event_exit_task, it's OK because the
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* context has been detached from its task.
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*/
|
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static void perf_event_remove_from_context(struct perf_event *event)
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{
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struct perf_event_context *ctx = event->ctx;
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struct task_struct *task = ctx->task;
|
|
|
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if (!task) {
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/*
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* Per cpu events are removed via an smp call and
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* the removal is always sucessful.
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*/
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smp_call_function_single(event->cpu,
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__perf_event_remove_from_context,
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event, 1);
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return;
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}
|
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|
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retry:
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task_oncpu_function_call(task, __perf_event_remove_from_context,
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event);
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|
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spin_lock_irq(&ctx->lock);
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/*
|
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* If the context is active we need to retry the smp call.
|
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*/
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if (ctx->nr_active && !list_empty(&event->group_entry)) {
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spin_unlock_irq(&ctx->lock);
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goto retry;
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}
|
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|
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/*
|
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* The lock prevents that this context is scheduled in so we
|
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* can remove the event safely, if the call above did not
|
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* succeed.
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*/
|
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if (!list_empty(&event->group_entry)) {
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list_del_event(event, ctx);
|
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}
|
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spin_unlock_irq(&ctx->lock);
|
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}
|
|
|
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static inline u64 perf_clock(void)
|
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{
|
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return cpu_clock(smp_processor_id());
|
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}
|
|
|
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/*
|
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* Update the record of the current time in a context.
|
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*/
|
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static void update_context_time(struct perf_event_context *ctx)
|
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{
|
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u64 now = perf_clock();
|
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|
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ctx->time += now - ctx->timestamp;
|
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ctx->timestamp = now;
|
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}
|
|
|
|
/*
|
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* Update the total_time_enabled and total_time_running fields for a event.
|
|
*/
|
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static void update_event_times(struct perf_event *event)
|
|
{
|
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struct perf_event_context *ctx = event->ctx;
|
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u64 run_end;
|
|
|
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if (event->state < PERF_EVENT_STATE_INACTIVE ||
|
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event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
|
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return;
|
|
|
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event->total_time_enabled = ctx->time - event->tstamp_enabled;
|
|
|
|
if (event->state == PERF_EVENT_STATE_INACTIVE)
|
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run_end = event->tstamp_stopped;
|
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else
|
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run_end = ctx->time;
|
|
|
|
event->total_time_running = run_end - event->tstamp_running;
|
|
}
|
|
|
|
/*
|
|
* Update total_time_enabled and total_time_running for all events in a group.
|
|
*/
|
|
static void update_group_times(struct perf_event *leader)
|
|
{
|
|
struct perf_event *event;
|
|
|
|
update_event_times(leader);
|
|
list_for_each_entry(event, &leader->sibling_list, group_entry)
|
|
update_event_times(event);
|
|
}
|
|
|
|
/*
|
|
* Cross CPU call to disable a performance event
|
|
*/
|
|
static void __perf_event_disable(void *info)
|
|
{
|
|
struct perf_event *event = info;
|
|
struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
|
|
struct perf_event_context *ctx = event->ctx;
|
|
|
|
/*
|
|
* If this is a per-task event, need to check whether this
|
|
* event's task is the current task on this cpu.
|
|
*/
|
|
if (ctx->task && cpuctx->task_ctx != ctx)
|
|
return;
|
|
|
|
spin_lock(&ctx->lock);
|
|
|
|
/*
|
|
* If the event is on, turn it off.
|
|
* If it is in error state, leave it in error state.
|
|
*/
|
|
if (event->state >= PERF_EVENT_STATE_INACTIVE) {
|
|
update_context_time(ctx);
|
|
update_group_times(event);
|
|
if (event == event->group_leader)
|
|
group_sched_out(event, cpuctx, ctx);
|
|
else
|
|
event_sched_out(event, cpuctx, ctx);
|
|
event->state = PERF_EVENT_STATE_OFF;
|
|
}
|
|
|
|
spin_unlock(&ctx->lock);
|
|
}
|
|
|
|
/*
|
|
* Disable a event.
|
|
*
|
|
* If event->ctx is a cloned context, callers must make sure that
|
|
* every task struct that event->ctx->task could possibly point to
|
|
* remains valid. This condition is satisifed when called through
|
|
* perf_event_for_each_child or perf_event_for_each because they
|
|
* hold the top-level event's child_mutex, so any descendant that
|
|
* goes to exit will block in sync_child_event.
|
|
* When called from perf_pending_event it's OK because event->ctx
|
|
* is the current context on this CPU and preemption is disabled,
|
|
* hence we can't get into perf_event_task_sched_out for this context.
|
|
*/
|
|
static void perf_event_disable(struct perf_event *event)
|
|
{
|
|
struct perf_event_context *ctx = event->ctx;
|
|
struct task_struct *task = ctx->task;
|
|
|
|
if (!task) {
|
|
/*
|
|
* Disable the event on the cpu that it's on
|
|
*/
|
|
smp_call_function_single(event->cpu, __perf_event_disable,
|
|
event, 1);
|
|
return;
|
|
}
|
|
|
|
retry:
|
|
task_oncpu_function_call(task, __perf_event_disable, event);
|
|
|
|
spin_lock_irq(&ctx->lock);
|
|
/*
|
|
* If the event is still active, we need to retry the cross-call.
|
|
*/
|
|
if (event->state == PERF_EVENT_STATE_ACTIVE) {
|
|
spin_unlock_irq(&ctx->lock);
|
|
goto retry;
|
|
}
|
|
|
|
/*
|
|
* Since we have the lock this context can't be scheduled
|
|
* in, so we can change the state safely.
|
|
*/
|
|
if (event->state == PERF_EVENT_STATE_INACTIVE) {
|
|
update_group_times(event);
|
|
event->state = PERF_EVENT_STATE_OFF;
|
|
}
|
|
|
|
spin_unlock_irq(&ctx->lock);
|
|
}
|
|
|
|
static int
|
|
event_sched_in(struct perf_event *event,
|
|
struct perf_cpu_context *cpuctx,
|
|
struct perf_event_context *ctx,
|
|
int cpu)
|
|
{
|
|
if (event->state <= PERF_EVENT_STATE_OFF)
|
|
return 0;
|
|
|
|
event->state = PERF_EVENT_STATE_ACTIVE;
|
|
event->oncpu = cpu; /* TODO: put 'cpu' into cpuctx->cpu */
|
|
/*
|
|
* The new state must be visible before we turn it on in the hardware:
|
|
*/
|
|
smp_wmb();
|
|
|
|
if (event->pmu->enable(event)) {
|
|
event->state = PERF_EVENT_STATE_INACTIVE;
|
|
event->oncpu = -1;
|
|
return -EAGAIN;
|
|
}
|
|
|
|
event->tstamp_running += ctx->time - event->tstamp_stopped;
|
|
|
|
if (!is_software_event(event))
|
|
cpuctx->active_oncpu++;
|
|
ctx->nr_active++;
|
|
|
|
if (event->attr.exclusive)
|
|
cpuctx->exclusive = 1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
group_sched_in(struct perf_event *group_event,
|
|
struct perf_cpu_context *cpuctx,
|
|
struct perf_event_context *ctx,
|
|
int cpu)
|
|
{
|
|
struct perf_event *event, *partial_group;
|
|
int ret;
|
|
|
|
if (group_event->state == PERF_EVENT_STATE_OFF)
|
|
return 0;
|
|
|
|
ret = hw_perf_group_sched_in(group_event, cpuctx, ctx, cpu);
|
|
if (ret)
|
|
return ret < 0 ? ret : 0;
|
|
|
|
if (event_sched_in(group_event, cpuctx, ctx, cpu))
|
|
return -EAGAIN;
|
|
|
|
/*
|
|
* Schedule in siblings as one group (if any):
|
|
*/
|
|
list_for_each_entry(event, &group_event->sibling_list, group_entry) {
|
|
if (event_sched_in(event, cpuctx, ctx, cpu)) {
|
|
partial_group = event;
|
|
goto group_error;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
|
|
group_error:
|
|
/*
|
|
* Groups can be scheduled in as one unit only, so undo any
|
|
* partial group before returning:
|
|
*/
|
|
list_for_each_entry(event, &group_event->sibling_list, group_entry) {
|
|
if (event == partial_group)
|
|
break;
|
|
event_sched_out(event, cpuctx, ctx);
|
|
}
|
|
event_sched_out(group_event, cpuctx, ctx);
|
|
|
|
return -EAGAIN;
|
|
}
|
|
|
|
/*
|
|
* Return 1 for a group consisting entirely of software events,
|
|
* 0 if the group contains any hardware events.
|
|
*/
|
|
static int is_software_only_group(struct perf_event *leader)
|
|
{
|
|
struct perf_event *event;
|
|
|
|
if (!is_software_event(leader))
|
|
return 0;
|
|
|
|
list_for_each_entry(event, &leader->sibling_list, group_entry)
|
|
if (!is_software_event(event))
|
|
return 0;
|
|
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* 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 (is_software_only_group(event))
|
|
return 1;
|
|
/*
|
|
* If an exclusive group is already on, no other hardware
|
|
* events can go on.
|
|
*/
|
|
if (cpuctx->exclusive)
|
|
return 0;
|
|
/*
|
|
* If this group is exclusive and there are already
|
|
* events on the CPU, it can't go on.
|
|
*/
|
|
if (event->attr.exclusive && cpuctx->active_oncpu)
|
|
return 0;
|
|
/*
|
|
* Otherwise, try to add it if all previous groups were able
|
|
* to go on.
|
|
*/
|
|
return can_add_hw;
|
|
}
|
|
|
|
static void add_event_to_ctx(struct perf_event *event,
|
|
struct perf_event_context *ctx)
|
|
{
|
|
list_add_event(event, ctx);
|
|
event->tstamp_enabled = ctx->time;
|
|
event->tstamp_running = ctx->time;
|
|
event->tstamp_stopped = ctx->time;
|
|
}
|
|
|
|
/*
|
|
* Cross CPU call to install and enable a performance event
|
|
*
|
|
* Must be called with ctx->mutex held
|
|
*/
|
|
static void __perf_install_in_context(void *info)
|
|
{
|
|
struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
|
|
struct perf_event *event = info;
|
|
struct perf_event_context *ctx = event->ctx;
|
|
struct perf_event *leader = event->group_leader;
|
|
int cpu = smp_processor_id();
|
|
int err;
|
|
|
|
/*
|
|
* 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.
|
|
* Or possibly this is the right context but it isn't
|
|
* on this cpu because it had no events.
|
|
*/
|
|
if (ctx->task && cpuctx->task_ctx != ctx) {
|
|
if (cpuctx->task_ctx || ctx->task != current)
|
|
return;
|
|
cpuctx->task_ctx = ctx;
|
|
}
|
|
|
|
spin_lock(&ctx->lock);
|
|
ctx->is_active = 1;
|
|
update_context_time(ctx);
|
|
|
|
/*
|
|
* Protect the list operation against NMI by disabling the
|
|
* events on a global level. NOP for non NMI based events.
|
|
*/
|
|
perf_disable();
|
|
|
|
add_event_to_ctx(event, ctx);
|
|
|
|
/*
|
|
* Don't put the event on if it is disabled or if
|
|
* it is in a group and the group isn't on.
|
|
*/
|
|
if (event->state != PERF_EVENT_STATE_INACTIVE ||
|
|
(leader != event && leader->state != PERF_EVENT_STATE_ACTIVE))
|
|
goto unlock;
|
|
|
|
/*
|
|
* An exclusive event can't go on if there are already active
|
|
* hardware events, and no hardware event can go on if there
|
|
* is already an exclusive event on.
|
|
*/
|
|
if (!group_can_go_on(event, cpuctx, 1))
|
|
err = -EEXIST;
|
|
else
|
|
err = event_sched_in(event, cpuctx, ctx, cpu);
|
|
|
|
if (err) {
|
|
/*
|
|
* This event couldn't go on. If it is in a group
|
|
* then we have to pull the whole group off.
|
|
* If the event group is pinned then put it in error state.
|
|
*/
|
|
if (leader != event)
|
|
group_sched_out(leader, cpuctx, ctx);
|
|
if (leader->attr.pinned) {
|
|
update_group_times(leader);
|
|
leader->state = PERF_EVENT_STATE_ERROR;
|
|
}
|
|
}
|
|
|
|
if (!err && !ctx->task && cpuctx->max_pertask)
|
|
cpuctx->max_pertask--;
|
|
|
|
unlock:
|
|
perf_enable();
|
|
|
|
spin_unlock(&ctx->lock);
|
|
}
|
|
|
|
/*
|
|
* Attach a performance event to a context
|
|
*
|
|
* First we add the event to the list with the hardware enable bit
|
|
* in event->hw_config cleared.
|
|
*
|
|
* If the event is attached to a task which is on a CPU we use a smp
|
|
* call to enable it in the task context. The task might have been
|
|
* scheduled away, but we check this in the smp call again.
|
|
*
|
|
* Must be called with ctx->mutex held.
|
|
*/
|
|
static void
|
|
perf_install_in_context(struct perf_event_context *ctx,
|
|
struct perf_event *event,
|
|
int cpu)
|
|
{
|
|
struct task_struct *task = ctx->task;
|
|
|
|
if (!task) {
|
|
/*
|
|
* Per cpu events are installed via an smp call and
|
|
* the install is always sucessful.
|
|
*/
|
|
smp_call_function_single(cpu, __perf_install_in_context,
|
|
event, 1);
|
|
return;
|
|
}
|
|
|
|
retry:
|
|
task_oncpu_function_call(task, __perf_install_in_context,
|
|
event);
|
|
|
|
spin_lock_irq(&ctx->lock);
|
|
/*
|
|
* we need to retry the smp call.
|
|
*/
|
|
if (ctx->is_active && list_empty(&event->group_entry)) {
|
|
spin_unlock_irq(&ctx->lock);
|
|
goto retry;
|
|
}
|
|
|
|
/*
|
|
* The lock prevents that this context is scheduled in so we
|
|
* can add the event safely, if it the call above did not
|
|
* succeed.
|
|
*/
|
|
if (list_empty(&event->group_entry))
|
|
add_event_to_ctx(event, ctx);
|
|
spin_unlock_irq(&ctx->lock);
|
|
}
|
|
|
|
/*
|
|
* Put a event into inactive state and update time fields.
|
|
* Enabling the leader of a group effectively enables all
|
|
* the group members that aren't explicitly disabled, so we
|
|
* have to update their ->tstamp_enabled also.
|
|
* Note: this works for group members as well as group leaders
|
|
* since the non-leader members' sibling_lists will be empty.
|
|
*/
|
|
static void __perf_event_mark_enabled(struct perf_event *event,
|
|
struct perf_event_context *ctx)
|
|
{
|
|
struct perf_event *sub;
|
|
|
|
event->state = PERF_EVENT_STATE_INACTIVE;
|
|
event->tstamp_enabled = ctx->time - event->total_time_enabled;
|
|
list_for_each_entry(sub, &event->sibling_list, group_entry)
|
|
if (sub->state >= PERF_EVENT_STATE_INACTIVE)
|
|
sub->tstamp_enabled =
|
|
ctx->time - sub->total_time_enabled;
|
|
}
|
|
|
|
/*
|
|
* Cross CPU call to enable a performance event
|
|
*/
|
|
static void __perf_event_enable(void *info)
|
|
{
|
|
struct perf_event *event = info;
|
|
struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
|
|
struct perf_event_context *ctx = event->ctx;
|
|
struct perf_event *leader = event->group_leader;
|
|
int err;
|
|
|
|
/*
|
|
* If this is a per-task event, need to check whether this
|
|
* event's task is the current task on this cpu.
|
|
*/
|
|
if (ctx->task && cpuctx->task_ctx != ctx) {
|
|
if (cpuctx->task_ctx || ctx->task != current)
|
|
return;
|
|
cpuctx->task_ctx = ctx;
|
|
}
|
|
|
|
spin_lock(&ctx->lock);
|
|
ctx->is_active = 1;
|
|
update_context_time(ctx);
|
|
|
|
if (event->state >= PERF_EVENT_STATE_INACTIVE)
|
|
goto unlock;
|
|
__perf_event_mark_enabled(event, ctx);
|
|
|
|
/*
|
|
* If the event is in a group and isn't the group leader,
|
|
* then don't put it on unless the group is on.
|
|
*/
|
|
if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)
|
|
goto unlock;
|
|
|
|
if (!group_can_go_on(event, cpuctx, 1)) {
|
|
err = -EEXIST;
|
|
} else {
|
|
perf_disable();
|
|
if (event == leader)
|
|
err = group_sched_in(event, cpuctx, ctx,
|
|
smp_processor_id());
|
|
else
|
|
err = event_sched_in(event, cpuctx, ctx,
|
|
smp_processor_id());
|
|
perf_enable();
|
|
}
|
|
|
|
if (err) {
|
|
/*
|
|
* If this event can't go on and it's part of a
|
|
* group, then the whole group has to come off.
|
|
*/
|
|
if (leader != event)
|
|
group_sched_out(leader, cpuctx, ctx);
|
|
if (leader->attr.pinned) {
|
|
update_group_times(leader);
|
|
leader->state = PERF_EVENT_STATE_ERROR;
|
|
}
|
|
}
|
|
|
|
unlock:
|
|
spin_unlock(&ctx->lock);
|
|
}
|
|
|
|
/*
|
|
* Enable a event.
|
|
*
|
|
* If event->ctx is a cloned context, callers must make sure that
|
|
* every task struct that event->ctx->task could possibly point to
|
|
* remains valid. This condition is satisfied when called through
|
|
* perf_event_for_each_child or perf_event_for_each as described
|
|
* for perf_event_disable.
|
|
*/
|
|
static void perf_event_enable(struct perf_event *event)
|
|
{
|
|
struct perf_event_context *ctx = event->ctx;
|
|
struct task_struct *task = ctx->task;
|
|
|
|
if (!task) {
|
|
/*
|
|
* Enable the event on the cpu that it's on
|
|
*/
|
|
smp_call_function_single(event->cpu, __perf_event_enable,
|
|
event, 1);
|
|
return;
|
|
}
|
|
|
|
spin_lock_irq(&ctx->lock);
|
|
if (event->state >= PERF_EVENT_STATE_INACTIVE)
|
|
goto out;
|
|
|
|
/*
|
|
* If the event is in error state, clear that first.
|
|
* That way, if we see the event in error state below, we
|
|
* know that it has gone back into error state, as distinct
|
|
* from the task having been scheduled away before the
|
|
* cross-call arrived.
|
|
*/
|
|
if (event->state == PERF_EVENT_STATE_ERROR)
|
|
event->state = PERF_EVENT_STATE_OFF;
|
|
|
|
retry:
|
|
spin_unlock_irq(&ctx->lock);
|
|
task_oncpu_function_call(task, __perf_event_enable, event);
|
|
|
|
spin_lock_irq(&ctx->lock);
|
|
|
|
/*
|
|
* If the context is active and the event is still off,
|
|
* we need to retry the cross-call.
|
|
*/
|
|
if (ctx->is_active && event->state == PERF_EVENT_STATE_OFF)
|
|
goto retry;
|
|
|
|
/*
|
|
* Since we have the lock this context can't be scheduled
|
|
* in, so we can change the state safely.
|
|
*/
|
|
if (event->state == PERF_EVENT_STATE_OFF)
|
|
__perf_event_mark_enabled(event, ctx);
|
|
|
|
out:
|
|
spin_unlock_irq(&ctx->lock);
|
|
}
|
|
|
|
static int perf_event_refresh(struct perf_event *event, int refresh)
|
|
{
|
|
/*
|
|
* not supported on inherited events
|
|
*/
|
|
if (event->attr.inherit)
|
|
return -EINVAL;
|
|
|
|
atomic_add(refresh, &event->event_limit);
|
|
perf_event_enable(event);
|
|
|
|
return 0;
|
|
}
|
|
|
|
void __perf_event_sched_out(struct perf_event_context *ctx,
|
|
struct perf_cpu_context *cpuctx)
|
|
{
|
|
struct perf_event *event;
|
|
|
|
spin_lock(&ctx->lock);
|
|
ctx->is_active = 0;
|
|
if (likely(!ctx->nr_events))
|
|
goto out;
|
|
update_context_time(ctx);
|
|
|
|
perf_disable();
|
|
if (ctx->nr_active)
|
|
list_for_each_entry(event, &ctx->group_list, group_entry)
|
|
group_sched_out(event, cpuctx, ctx);
|
|
|
|
perf_enable();
|
|
out:
|
|
spin_unlock(&ctx->lock);
|
|
}
|
|
|
|
/*
|
|
* Test whether two contexts are equivalent, i.e. whether they
|
|
* have both been cloned from the same version of the same context
|
|
* and they both have the same number of enabled events.
|
|
* If the number of enabled events is the same, then the set
|
|
* of enabled events should be the same, because these are both
|
|
* inherited contexts, therefore we can't access individual events
|
|
* in them directly with an fd; we can only enable/disable all
|
|
* events via prctl, or enable/disable all events in a family
|
|
* via ioctl, which will have the same effect on both contexts.
|
|
*/
|
|
static int context_equiv(struct perf_event_context *ctx1,
|
|
struct perf_event_context *ctx2)
|
|
{
|
|
return ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx
|
|
&& ctx1->parent_gen == ctx2->parent_gen
|
|
&& !ctx1->pin_count && !ctx2->pin_count;
|
|
}
|
|
|
|
static void __perf_event_read(void *event);
|
|
|
|
static void __perf_event_sync_stat(struct perf_event *event,
|
|
struct perf_event *next_event)
|
|
{
|
|
u64 value;
|
|
|
|
if (!event->attr.inherit_stat)
|
|
return;
|
|
|
|
/*
|
|
* Update the event value, we cannot use perf_event_read()
|
|
* because we're in the middle of a context switch and have IRQs
|
|
* disabled, which upsets smp_call_function_single(), however
|
|
* we know the event must be on the current CPU, therefore we
|
|
* don't need to use it.
|
|
*/
|
|
switch (event->state) {
|
|
case PERF_EVENT_STATE_ACTIVE:
|
|
__perf_event_read(event);
|
|
break;
|
|
|
|
case PERF_EVENT_STATE_INACTIVE:
|
|
update_event_times(event);
|
|
break;
|
|
|
|
default:
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* In order to keep per-task stats reliable we need to flip the event
|
|
* values when we flip the contexts.
|
|
*/
|
|
value = atomic64_read(&next_event->count);
|
|
value = atomic64_xchg(&event->count, value);
|
|
atomic64_set(&next_event->count, value);
|
|
|
|
swap(event->total_time_enabled, next_event->total_time_enabled);
|
|
swap(event->total_time_running, next_event->total_time_running);
|
|
|
|
/*
|
|
* Since we swizzled the values, update the user visible data too.
|
|
*/
|
|
perf_event_update_userpage(event);
|
|
perf_event_update_userpage(next_event);
|
|
}
|
|
|
|
#define list_next_entry(pos, member) \
|
|
list_entry(pos->member.next, typeof(*pos), member)
|
|
|
|
static void perf_event_sync_stat(struct perf_event_context *ctx,
|
|
struct perf_event_context *next_ctx)
|
|
{
|
|
struct perf_event *event, *next_event;
|
|
|
|
if (!ctx->nr_stat)
|
|
return;
|
|
|
|
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);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* 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 cpu)
|
|
{
|
|
struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
|
|
struct perf_event_context *ctx = task->perf_event_ctxp;
|
|
struct perf_event_context *next_ctx;
|
|
struct perf_event_context *parent;
|
|
struct pt_regs *regs;
|
|
int do_switch = 1;
|
|
|
|
regs = task_pt_regs(task);
|
|
perf_sw_event(PERF_COUNT_SW_CONTEXT_SWITCHES, 1, 1, regs, 0);
|
|
|
|
if (likely(!ctx || !cpuctx->task_ctx))
|
|
return;
|
|
|
|
update_context_time(ctx);
|
|
|
|
rcu_read_lock();
|
|
parent = rcu_dereference(ctx->parent_ctx);
|
|
next_ctx = next->perf_event_ctxp;
|
|
if (parent && next_ctx &&
|
|
rcu_dereference(next_ctx->parent_ctx) == parent) {
|
|
/*
|
|
* Looks like the two contexts are clones, so we might be
|
|
* able to optimize the context switch. We lock both
|
|
* contexts and check that they are clones under the
|
|
* lock (including re-checking that neither has been
|
|
* uncloned in the meantime). It doesn't matter which
|
|
* order we take the locks because no other cpu could
|
|
* be trying to lock both of these tasks.
|
|
*/
|
|
spin_lock(&ctx->lock);
|
|
spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
|
|
if (context_equiv(ctx, next_ctx)) {
|
|
/*
|
|
* XXX do we need a memory barrier of sorts
|
|
* wrt to rcu_dereference() of perf_event_ctxp
|
|
*/
|
|
task->perf_event_ctxp = next_ctx;
|
|
next->perf_event_ctxp = ctx;
|
|
ctx->task = next;
|
|
next_ctx->task = task;
|
|
do_switch = 0;
|
|
|
|
perf_event_sync_stat(ctx, next_ctx);
|
|
}
|
|
spin_unlock(&next_ctx->lock);
|
|
spin_unlock(&ctx->lock);
|
|
}
|
|
rcu_read_unlock();
|
|
|
|
if (do_switch) {
|
|
__perf_event_sched_out(ctx, cpuctx);
|
|
cpuctx->task_ctx = NULL;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Called with IRQs disabled
|
|
*/
|
|
static void __perf_event_task_sched_out(struct perf_event_context *ctx)
|
|
{
|
|
struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
|
|
|
|
if (!cpuctx->task_ctx)
|
|
return;
|
|
|
|
if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
|
|
return;
|
|
|
|
__perf_event_sched_out(ctx, cpuctx);
|
|
cpuctx->task_ctx = NULL;
|
|
}
|
|
|
|
/*
|
|
* Called with IRQs disabled
|
|
*/
|
|
static void perf_event_cpu_sched_out(struct perf_cpu_context *cpuctx)
|
|
{
|
|
__perf_event_sched_out(&cpuctx->ctx, cpuctx);
|
|
}
|
|
|
|
static void
|
|
__perf_event_sched_in(struct perf_event_context *ctx,
|
|
struct perf_cpu_context *cpuctx, int cpu)
|
|
{
|
|
struct perf_event *event;
|
|
int can_add_hw = 1;
|
|
|
|
spin_lock(&ctx->lock);
|
|
ctx->is_active = 1;
|
|
if (likely(!ctx->nr_events))
|
|
goto out;
|
|
|
|
ctx->timestamp = perf_clock();
|
|
|
|
perf_disable();
|
|
|
|
/*
|
|
* First go through the list and put on any pinned groups
|
|
* in order to give them the best chance of going on.
|
|
*/
|
|
list_for_each_entry(event, &ctx->group_list, group_entry) {
|
|
if (event->state <= PERF_EVENT_STATE_OFF ||
|
|
!event->attr.pinned)
|
|
continue;
|
|
if (event->cpu != -1 && event->cpu != cpu)
|
|
continue;
|
|
|
|
if (group_can_go_on(event, cpuctx, 1))
|
|
group_sched_in(event, cpuctx, ctx, cpu);
|
|
|
|
/*
|
|
* If this pinned group hasn't been scheduled,
|
|
* put it in error state.
|
|
*/
|
|
if (event->state == PERF_EVENT_STATE_INACTIVE) {
|
|
update_group_times(event);
|
|
event->state = PERF_EVENT_STATE_ERROR;
|
|
}
|
|
}
|
|
|
|
list_for_each_entry(event, &ctx->group_list, group_entry) {
|
|
/*
|
|
* Ignore events in OFF or ERROR state, and
|
|
* ignore pinned events since we did them already.
|
|
*/
|
|
if (event->state <= PERF_EVENT_STATE_OFF ||
|
|
event->attr.pinned)
|
|
continue;
|
|
|
|
/*
|
|
* Listen to the 'cpu' scheduling filter constraint
|
|
* of events:
|
|
*/
|
|
if (event->cpu != -1 && event->cpu != cpu)
|
|
continue;
|
|
|
|
if (group_can_go_on(event, cpuctx, can_add_hw))
|
|
if (group_sched_in(event, cpuctx, ctx, cpu))
|
|
can_add_hw = 0;
|
|
}
|
|
perf_enable();
|
|
out:
|
|
spin_unlock(&ctx->lock);
|
|
}
|
|
|
|
/*
|
|
* Called from scheduler to add the events of the current task
|
|
* with interrupts disabled.
|
|
*
|
|
* We restore the event value and then enable it.
|
|
*
|
|
* This does not protect us against NMI, but enable()
|
|
* sets the enabled bit in the control field of event _before_
|
|
* accessing the event control register. If a NMI hits, then it will
|
|
* keep the event running.
|
|
*/
|
|
void perf_event_task_sched_in(struct task_struct *task, int cpu)
|
|
{
|
|
struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
|
|
struct perf_event_context *ctx = task->perf_event_ctxp;
|
|
|
|
if (likely(!ctx))
|
|
return;
|
|
if (cpuctx->task_ctx == ctx)
|
|
return;
|
|
__perf_event_sched_in(ctx, cpuctx, cpu);
|
|
cpuctx->task_ctx = ctx;
|
|
}
|
|
|
|
static void perf_event_cpu_sched_in(struct perf_cpu_context *cpuctx, int cpu)
|
|
{
|
|
struct perf_event_context *ctx = &cpuctx->ctx;
|
|
|
|
__perf_event_sched_in(ctx, cpuctx, cpu);
|
|
}
|
|
|
|
#define MAX_INTERRUPTS (~0ULL)
|
|
|
|
static void perf_log_throttle(struct perf_event *event, int enable);
|
|
|
|
static void perf_adjust_period(struct perf_event *event, u64 events)
|
|
{
|
|
struct hw_perf_event *hwc = &event->hw;
|
|
u64 period, sample_period;
|
|
s64 delta;
|
|
|
|
events *= hwc->sample_period;
|
|
period = div64_u64(events, event->attr.sample_freq);
|
|
|
|
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;
|
|
}
|
|
|
|
static void perf_ctx_adjust_freq(struct perf_event_context *ctx)
|
|
{
|
|
struct perf_event *event;
|
|
struct hw_perf_event *hwc;
|
|
u64 interrupts, freq;
|
|
|
|
spin_lock(&ctx->lock);
|
|
list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
|
|
if (event->state != PERF_EVENT_STATE_ACTIVE)
|
|
continue;
|
|
|
|
hwc = &event->hw;
|
|
|
|
interrupts = hwc->interrupts;
|
|
hwc->interrupts = 0;
|
|
|
|
/*
|
|
* unthrottle events on the tick
|
|
*/
|
|
if (interrupts == MAX_INTERRUPTS) {
|
|
perf_log_throttle(event, 1);
|
|
event->pmu->unthrottle(event);
|
|
interrupts = 2*sysctl_perf_event_sample_rate/HZ;
|
|
}
|
|
|
|
if (!event->attr.freq || !event->attr.sample_freq)
|
|
continue;
|
|
|
|
/*
|
|
* if the specified freq < HZ then we need to skip ticks
|
|
*/
|
|
if (event->attr.sample_freq < HZ) {
|
|
freq = event->attr.sample_freq;
|
|
|
|
hwc->freq_count += freq;
|
|
hwc->freq_interrupts += interrupts;
|
|
|
|
if (hwc->freq_count < HZ)
|
|
continue;
|
|
|
|
interrupts = hwc->freq_interrupts;
|
|
hwc->freq_interrupts = 0;
|
|
hwc->freq_count -= HZ;
|
|
} else
|
|
freq = HZ;
|
|
|
|
perf_adjust_period(event, freq * interrupts);
|
|
|
|
/*
|
|
* In order to avoid being stalled by an (accidental) huge
|
|
* sample period, force reset the sample period if we didn't
|
|
* get any events in this freq period.
|
|
*/
|
|
if (!interrupts) {
|
|
perf_disable();
|
|
event->pmu->disable(event);
|
|
atomic64_set(&hwc->period_left, 0);
|
|
event->pmu->enable(event);
|
|
perf_enable();
|
|
}
|
|
}
|
|
spin_unlock(&ctx->lock);
|
|
}
|
|
|
|
/*
|
|
* Round-robin a context's events:
|
|
*/
|
|
static void rotate_ctx(struct perf_event_context *ctx)
|
|
{
|
|
struct perf_event *event;
|
|
|
|
if (!ctx->nr_events)
|
|
return;
|
|
|
|
spin_lock(&ctx->lock);
|
|
/*
|
|
* Rotate the first entry last (works just fine for group events too):
|
|
*/
|
|
perf_disable();
|
|
list_for_each_entry(event, &ctx->group_list, group_entry) {
|
|
list_move_tail(&event->group_entry, &ctx->group_list);
|
|
break;
|
|
}
|
|
perf_enable();
|
|
|
|
spin_unlock(&ctx->lock);
|
|
}
|
|
|
|
void perf_event_task_tick(struct task_struct *curr, int cpu)
|
|
{
|
|
struct perf_cpu_context *cpuctx;
|
|
struct perf_event_context *ctx;
|
|
|
|
if (!atomic_read(&nr_events))
|
|
return;
|
|
|
|
cpuctx = &per_cpu(perf_cpu_context, cpu);
|
|
ctx = curr->perf_event_ctxp;
|
|
|
|
perf_ctx_adjust_freq(&cpuctx->ctx);
|
|
if (ctx)
|
|
perf_ctx_adjust_freq(ctx);
|
|
|
|
perf_event_cpu_sched_out(cpuctx);
|
|
if (ctx)
|
|
__perf_event_task_sched_out(ctx);
|
|
|
|
rotate_ctx(&cpuctx->ctx);
|
|
if (ctx)
|
|
rotate_ctx(ctx);
|
|
|
|
perf_event_cpu_sched_in(cpuctx, cpu);
|
|
if (ctx)
|
|
perf_event_task_sched_in(curr, cpu);
|
|
}
|
|
|
|
/*
|
|
* Enable all of a task's events that have been marked enable-on-exec.
|
|
* This expects task == current.
|
|
*/
|
|
static void perf_event_enable_on_exec(struct task_struct *task)
|
|
{
|
|
struct perf_event_context *ctx;
|
|
struct perf_event *event;
|
|
unsigned long flags;
|
|
int enabled = 0;
|
|
|
|
local_irq_save(flags);
|
|
ctx = task->perf_event_ctxp;
|
|
if (!ctx || !ctx->nr_events)
|
|
goto out;
|
|
|
|
__perf_event_task_sched_out(ctx);
|
|
|
|
spin_lock(&ctx->lock);
|
|
|
|
list_for_each_entry(event, &ctx->group_list, group_entry) {
|
|
if (!event->attr.enable_on_exec)
|
|
continue;
|
|
event->attr.enable_on_exec = 0;
|
|
if (event->state >= PERF_EVENT_STATE_INACTIVE)
|
|
continue;
|
|
__perf_event_mark_enabled(event, ctx);
|
|
enabled = 1;
|
|
}
|
|
|
|
/*
|
|
* Unclone this context if we enabled any event.
|
|
*/
|
|
if (enabled)
|
|
unclone_ctx(ctx);
|
|
|
|
spin_unlock(&ctx->lock);
|
|
|
|
perf_event_task_sched_in(task, smp_processor_id());
|
|
out:
|
|
local_irq_restore(flags);
|
|
}
|
|
|
|
/*
|
|
* Cross CPU call to read the hardware event
|
|
*/
|
|
static void __perf_event_read(void *info)
|
|
{
|
|
struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
|
|
struct perf_event *event = info;
|
|
struct perf_event_context *ctx = event->ctx;
|
|
unsigned long flags;
|
|
|
|
/*
|
|
* 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;
|
|
|
|
local_irq_save(flags);
|
|
if (ctx->is_active)
|
|
update_context_time(ctx);
|
|
event->pmu->read(event);
|
|
update_event_times(event);
|
|
local_irq_restore(flags);
|
|
}
|
|
|
|
static u64 perf_event_read(struct perf_event *event)
|
|
{
|
|
/*
|
|
* If event is enabled and currently active on a CPU, update the
|
|
* value in the event structure:
|
|
*/
|
|
if (event->state == PERF_EVENT_STATE_ACTIVE) {
|
|
smp_call_function_single(event->oncpu,
|
|
__perf_event_read, event, 1);
|
|
} else if (event->state == PERF_EVENT_STATE_INACTIVE) {
|
|
update_event_times(event);
|
|
}
|
|
|
|
return atomic64_read(&event->count);
|
|
}
|
|
|
|
/*
|
|
* Initialize the perf_event context in a task_struct:
|
|
*/
|
|
static void
|
|
__perf_event_init_context(struct perf_event_context *ctx,
|
|
struct task_struct *task)
|
|
{
|
|
memset(ctx, 0, sizeof(*ctx));
|
|
spin_lock_init(&ctx->lock);
|
|
mutex_init(&ctx->mutex);
|
|
INIT_LIST_HEAD(&ctx->group_list);
|
|
INIT_LIST_HEAD(&ctx->event_list);
|
|
atomic_set(&ctx->refcount, 1);
|
|
ctx->task = task;
|
|
}
|
|
|
|
static struct perf_event_context *find_get_context(pid_t pid, int cpu)
|
|
{
|
|
struct perf_event_context *ctx;
|
|
struct perf_cpu_context *cpuctx;
|
|
struct task_struct *task;
|
|
unsigned long flags;
|
|
int err;
|
|
|
|
/*
|
|
* If cpu is not a wildcard then this is a percpu event:
|
|
*/
|
|
if (cpu != -1) {
|
|
/* Must be root to operate on a CPU event: */
|
|
if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
|
|
return ERR_PTR(-EACCES);
|
|
|
|
if (cpu < 0 || cpu > num_possible_cpus())
|
|
return ERR_PTR(-EINVAL);
|
|
|
|
/*
|
|
* We could be clever and allow to attach a event to an
|
|
* offline CPU and activate it when the CPU comes up, but
|
|
* that's for later.
|
|
*/
|
|
if (!cpu_isset(cpu, cpu_online_map))
|
|
return ERR_PTR(-ENODEV);
|
|
|
|
cpuctx = &per_cpu(perf_cpu_context, cpu);
|
|
ctx = &cpuctx->ctx;
|
|
get_ctx(ctx);
|
|
|
|
return ctx;
|
|
}
|
|
|
|
rcu_read_lock();
|
|
if (!pid)
|
|
task = current;
|
|
else
|
|
task = find_task_by_vpid(pid);
|
|
if (task)
|
|
get_task_struct(task);
|
|
rcu_read_unlock();
|
|
|
|
if (!task)
|
|
return ERR_PTR(-ESRCH);
|
|
|
|
/*
|
|
* Can't attach events to a dying task.
|
|
*/
|
|
err = -ESRCH;
|
|
if (task->flags & PF_EXITING)
|
|
goto errout;
|
|
|
|
/* Reuse ptrace permission checks for now. */
|
|
err = -EACCES;
|
|
if (!ptrace_may_access(task, PTRACE_MODE_READ))
|
|
goto errout;
|
|
|
|
retry:
|
|
ctx = perf_lock_task_context(task, &flags);
|
|
if (ctx) {
|
|
unclone_ctx(ctx);
|
|
spin_unlock_irqrestore(&ctx->lock, flags);
|
|
}
|
|
|
|
if (!ctx) {
|
|
ctx = kmalloc(sizeof(struct perf_event_context), GFP_KERNEL);
|
|
err = -ENOMEM;
|
|
if (!ctx)
|
|
goto errout;
|
|
__perf_event_init_context(ctx, task);
|
|
get_ctx(ctx);
|
|
if (cmpxchg(&task->perf_event_ctxp, NULL, ctx)) {
|
|
/*
|
|
* We raced with some other task; use
|
|
* the context they set.
|
|
*/
|
|
kfree(ctx);
|
|
goto retry;
|
|
}
|
|
get_task_struct(task);
|
|
}
|
|
|
|
put_task_struct(task);
|
|
return ctx;
|
|
|
|
errout:
|
|
put_task_struct(task);
|
|
return ERR_PTR(err);
|
|
}
|
|
|
|
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);
|
|
kfree(event);
|
|
}
|
|
|
|
static void perf_pending_sync(struct perf_event *event);
|
|
|
|
static void free_event(struct perf_event *event)
|
|
{
|
|
perf_pending_sync(event);
|
|
|
|
if (!event->parent) {
|
|
atomic_dec(&nr_events);
|
|
if (event->attr.mmap)
|
|
atomic_dec(&nr_mmap_events);
|
|
if (event->attr.comm)
|
|
atomic_dec(&nr_comm_events);
|
|
if (event->attr.task)
|
|
atomic_dec(&nr_task_events);
|
|
}
|
|
|
|
if (event->output) {
|
|
fput(event->output->filp);
|
|
event->output = NULL;
|
|
}
|
|
|
|
if (event->destroy)
|
|
event->destroy(event);
|
|
|
|
put_ctx(event->ctx);
|
|
call_rcu(&event->rcu_head, free_event_rcu);
|
|
}
|
|
|
|
/*
|
|
* Called when the last reference to the file is gone.
|
|
*/
|
|
static int perf_release(struct inode *inode, struct file *file)
|
|
{
|
|
struct perf_event *event = file->private_data;
|
|
struct perf_event_context *ctx = event->ctx;
|
|
|
|
file->private_data = NULL;
|
|
|
|
WARN_ON_ONCE(ctx->parent_ctx);
|
|
mutex_lock(&ctx->mutex);
|
|
perf_event_remove_from_context(event);
|
|
mutex_unlock(&ctx->mutex);
|
|
|
|
mutex_lock(&event->owner->perf_event_mutex);
|
|
list_del_init(&event->owner_entry);
|
|
mutex_unlock(&event->owner->perf_event_mutex);
|
|
put_task_struct(event->owner);
|
|
|
|
free_event(event);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int perf_event_read_size(struct perf_event *event)
|
|
{
|
|
int entry = sizeof(u64); /* value */
|
|
int size = 0;
|
|
int nr = 1;
|
|
|
|
if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
|
|
size += sizeof(u64);
|
|
|
|
if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
|
|
size += sizeof(u64);
|
|
|
|
if (event->attr.read_format & PERF_FORMAT_ID)
|
|
entry += sizeof(u64);
|
|
|
|
if (event->attr.read_format & PERF_FORMAT_GROUP) {
|
|
nr += event->group_leader->nr_siblings;
|
|
size += sizeof(u64);
|
|
}
|
|
|
|
size += entry * nr;
|
|
|
|
return size;
|
|
}
|
|
|
|
static u64 perf_event_read_value(struct perf_event *event)
|
|
{
|
|
struct perf_event *child;
|
|
u64 total = 0;
|
|
|
|
total += perf_event_read(event);
|
|
list_for_each_entry(child, &event->child_list, child_list)
|
|
total += perf_event_read(child);
|
|
|
|
return total;
|
|
}
|
|
|
|
static int perf_event_read_entry(struct perf_event *event,
|
|
u64 read_format, char __user *buf)
|
|
{
|
|
int n = 0, count = 0;
|
|
u64 values[2];
|
|
|
|
values[n++] = perf_event_read_value(event);
|
|
if (read_format & PERF_FORMAT_ID)
|
|
values[n++] = primary_event_id(event);
|
|
|
|
count = n * sizeof(u64);
|
|
|
|
if (copy_to_user(buf, values, count))
|
|
return -EFAULT;
|
|
|
|
return count;
|
|
}
|
|
|
|
static int perf_event_read_group(struct perf_event *event,
|
|
u64 read_format, char __user *buf)
|
|
{
|
|
struct perf_event *leader = event->group_leader, *sub;
|
|
int n = 0, size = 0, err = -EFAULT;
|
|
u64 values[3];
|
|
|
|
values[n++] = 1 + leader->nr_siblings;
|
|
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);
|
|
}
|
|
|
|
size = n * sizeof(u64);
|
|
|
|
if (copy_to_user(buf, values, size))
|
|
return -EFAULT;
|
|
|
|
err = perf_event_read_entry(leader, read_format, buf + size);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
size += err;
|
|
|
|
list_for_each_entry(sub, &leader->sibling_list, group_entry) {
|
|
err = perf_event_read_entry(sub, read_format,
|
|
buf + size);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
size += err;
|
|
}
|
|
|
|
return size;
|
|
}
|
|
|
|
static int perf_event_read_one(struct perf_event *event,
|
|
u64 read_format, char __user *buf)
|
|
{
|
|
u64 values[4];
|
|
int n = 0;
|
|
|
|
values[n++] = perf_event_read_value(event);
|
|
if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
|
|
values[n++] = event->total_time_enabled +
|
|
atomic64_read(&event->child_total_time_enabled);
|
|
}
|
|
if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
|
|
values[n++] = event->total_time_running +
|
|
atomic64_read(&event->child_total_time_running);
|
|
}
|
|
if (read_format & PERF_FORMAT_ID)
|
|
values[n++] = primary_event_id(event);
|
|
|
|
if (copy_to_user(buf, values, n * sizeof(u64)))
|
|
return -EFAULT;
|
|
|
|
return n * sizeof(u64);
|
|
}
|
|
|
|
/*
|
|
* Read the performance event - simple non blocking version for now
|
|
*/
|
|
static ssize_t
|
|
perf_read_hw(struct perf_event *event, char __user *buf, size_t count)
|
|
{
|
|
u64 read_format = event->attr.read_format;
|
|
int ret;
|
|
|
|
/*
|
|
* Return end-of-file for a read on a event that is in
|
|
* error state (i.e. because it was pinned but it couldn't be
|
|
* scheduled on to the CPU at some point).
|
|
*/
|
|
if (event->state == PERF_EVENT_STATE_ERROR)
|
|
return 0;
|
|
|
|
if (count < perf_event_read_size(event))
|
|
return -ENOSPC;
|
|
|
|
WARN_ON_ONCE(event->ctx->parent_ctx);
|
|
mutex_lock(&event->child_mutex);
|
|
if (read_format & PERF_FORMAT_GROUP)
|
|
ret = perf_event_read_group(event, read_format, buf);
|
|
else
|
|
ret = perf_event_read_one(event, read_format, buf);
|
|
mutex_unlock(&event->child_mutex);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static ssize_t
|
|
perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
|
|
{
|
|
struct perf_event *event = file->private_data;
|
|
|
|
return perf_read_hw(event, buf, count);
|
|
}
|
|
|
|
static unsigned int perf_poll(struct file *file, poll_table *wait)
|
|
{
|
|
struct perf_event *event = file->private_data;
|
|
struct perf_mmap_data *data;
|
|
unsigned int events = POLL_HUP;
|
|
|
|
rcu_read_lock();
|
|
data = rcu_dereference(event->data);
|
|
if (data)
|
|
events = atomic_xchg(&data->poll, 0);
|
|
rcu_read_unlock();
|
|
|
|
poll_wait(file, &event->waitq, wait);
|
|
|
|
return events;
|
|
}
|
|
|
|
static void perf_event_reset(struct perf_event *event)
|
|
{
|
|
(void)perf_event_read(event);
|
|
atomic64_set(&event->count, 0);
|
|
perf_event_update_userpage(event);
|
|
}
|
|
|
|
/*
|
|
* Holding the top-level event's child_mutex means that any
|
|
* descendant process that has inherited this event will block
|
|
* in sync_child_event if it goes to exit, thus satisfying the
|
|
* task existence requirements of perf_event_enable/disable.
|
|
*/
|
|
static void perf_event_for_each_child(struct perf_event *event,
|
|
void (*func)(struct perf_event *))
|
|
{
|
|
struct perf_event *child;
|
|
|
|
WARN_ON_ONCE(event->ctx->parent_ctx);
|
|
mutex_lock(&event->child_mutex);
|
|
func(event);
|
|
list_for_each_entry(child, &event->child_list, child_list)
|
|
func(child);
|
|
mutex_unlock(&event->child_mutex);
|
|
}
|
|
|
|
static void perf_event_for_each(struct perf_event *event,
|
|
void (*func)(struct perf_event *))
|
|
{
|
|
struct perf_event_context *ctx = event->ctx;
|
|
struct perf_event *sibling;
|
|
|
|
WARN_ON_ONCE(ctx->parent_ctx);
|
|
mutex_lock(&ctx->mutex);
|
|
event = event->group_leader;
|
|
|
|
perf_event_for_each_child(event, func);
|
|
func(event);
|
|
list_for_each_entry(sibling, &event->sibling_list, group_entry)
|
|
perf_event_for_each_child(event, func);
|
|
mutex_unlock(&ctx->mutex);
|
|
}
|
|
|
|
static int perf_event_period(struct perf_event *event, u64 __user *arg)
|
|
{
|
|
struct perf_event_context *ctx = event->ctx;
|
|
unsigned long size;
|
|
int ret = 0;
|
|
u64 value;
|
|
|
|
if (!event->attr.sample_period)
|
|
return -EINVAL;
|
|
|
|
size = copy_from_user(&value, arg, sizeof(value));
|
|
if (size != sizeof(value))
|
|
return -EFAULT;
|
|
|
|
if (!value)
|
|
return -EINVAL;
|
|
|
|
spin_lock_irq(&ctx->lock);
|
|
if (event->attr.freq) {
|
|
if (value > sysctl_perf_event_sample_rate) {
|
|
ret = -EINVAL;
|
|
goto unlock;
|
|
}
|
|
|
|
event->attr.sample_freq = value;
|
|
} else {
|
|
event->attr.sample_period = value;
|
|
event->hw.sample_period = value;
|
|
}
|
|
unlock:
|
|
spin_unlock_irq(&ctx->lock);
|
|
|
|
return ret;
|
|
}
|
|
|
|
int perf_event_set_output(struct perf_event *event, int output_fd);
|
|
|
|
static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
|
|
{
|
|
struct perf_event *event = file->private_data;
|
|
void (*func)(struct perf_event *);
|
|
u32 flags = arg;
|
|
|
|
switch (cmd) {
|
|
case PERF_EVENT_IOC_ENABLE:
|
|
func = perf_event_enable;
|
|
break;
|
|
case PERF_EVENT_IOC_DISABLE:
|
|
func = perf_event_disable;
|
|
break;
|
|
case PERF_EVENT_IOC_RESET:
|
|
func = perf_event_reset;
|
|
break;
|
|
|
|
case PERF_EVENT_IOC_REFRESH:
|
|
return perf_event_refresh(event, arg);
|
|
|
|
case PERF_EVENT_IOC_PERIOD:
|
|
return perf_event_period(event, (u64 __user *)arg);
|
|
|
|
case PERF_EVENT_IOC_SET_OUTPUT:
|
|
return perf_event_set_output(event, arg);
|
|
|
|
default:
|
|
return -ENOTTY;
|
|
}
|
|
|
|
if (flags & PERF_IOC_FLAG_GROUP)
|
|
perf_event_for_each(event, func);
|
|
else
|
|
perf_event_for_each_child(event, func);
|
|
|
|
return 0;
|
|
}
|
|
|
|
int perf_event_task_enable(void)
|
|
{
|
|
struct perf_event *event;
|
|
|
|
mutex_lock(¤t->perf_event_mutex);
|
|
list_for_each_entry(event, ¤t->perf_event_list, owner_entry)
|
|
perf_event_for_each_child(event, perf_event_enable);
|
|
mutex_unlock(¤t->perf_event_mutex);
|
|
|
|
return 0;
|
|
}
|
|
|
|
int perf_event_task_disable(void)
|
|
{
|
|
struct perf_event *event;
|
|
|
|
mutex_lock(¤t->perf_event_mutex);
|
|
list_for_each_entry(event, ¤t->perf_event_list, owner_entry)
|
|
perf_event_for_each_child(event, perf_event_disable);
|
|
mutex_unlock(¤t->perf_event_mutex);
|
|
|
|
return 0;
|
|
}
|
|
|
|
#ifndef PERF_EVENT_INDEX_OFFSET
|
|
# define PERF_EVENT_INDEX_OFFSET 0
|
|
#endif
|
|
|
|
static int perf_event_index(struct perf_event *event)
|
|
{
|
|
if (event->state != PERF_EVENT_STATE_ACTIVE)
|
|
return 0;
|
|
|
|
return event->hw.idx + 1 - PERF_EVENT_INDEX_OFFSET;
|
|
}
|
|
|
|
/*
|
|
* Callers need to ensure there can be no nesting of this function, otherwise
|
|
* the seqlock logic goes bad. We can not serialize this because the arch
|
|
* code calls this from NMI context.
|
|
*/
|
|
void perf_event_update_userpage(struct perf_event *event)
|
|
{
|
|
struct perf_event_mmap_page *userpg;
|
|
struct perf_mmap_data *data;
|
|
|
|
rcu_read_lock();
|
|
data = rcu_dereference(event->data);
|
|
if (!data)
|
|
goto unlock;
|
|
|
|
userpg = data->user_page;
|
|
|
|
/*
|
|
* Disable preemption so as to not let the corresponding user-space
|
|
* spin too long if we get preempted.
|
|
*/
|
|
preempt_disable();
|
|
++userpg->lock;
|
|
barrier();
|
|
userpg->index = perf_event_index(event);
|
|
userpg->offset = atomic64_read(&event->count);
|
|
if (event->state == PERF_EVENT_STATE_ACTIVE)
|
|
userpg->offset -= atomic64_read(&event->hw.prev_count);
|
|
|
|
userpg->time_enabled = event->total_time_enabled +
|
|
atomic64_read(&event->child_total_time_enabled);
|
|
|
|
userpg->time_running = event->total_time_running +
|
|
atomic64_read(&event->child_total_time_running);
|
|
|
|
barrier();
|
|
++userpg->lock;
|
|
preempt_enable();
|
|
unlock:
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
static unsigned long perf_data_size(struct perf_mmap_data *data)
|
|
{
|
|
return data->nr_pages << (PAGE_SHIFT + data->data_order);
|
|
}
|
|
|
|
#ifndef CONFIG_PERF_USE_VMALLOC
|
|
|
|
/*
|
|
* Back perf_mmap() with regular GFP_KERNEL-0 pages.
|
|
*/
|
|
|
|
static struct page *
|
|
perf_mmap_to_page(struct perf_mmap_data *data, unsigned long pgoff)
|
|
{
|
|
if (pgoff > data->nr_pages)
|
|
return NULL;
|
|
|
|
if (pgoff == 0)
|
|
return virt_to_page(data->user_page);
|
|
|
|
return virt_to_page(data->data_pages[pgoff - 1]);
|
|
}
|
|
|
|
static struct perf_mmap_data *
|
|
perf_mmap_data_alloc(struct perf_event *event, int nr_pages)
|
|
{
|
|
struct perf_mmap_data *data;
|
|
unsigned long size;
|
|
int i;
|
|
|
|
WARN_ON(atomic_read(&event->mmap_count));
|
|
|
|
size = sizeof(struct perf_mmap_data);
|
|
size += nr_pages * sizeof(void *);
|
|
|
|
data = kzalloc(size, GFP_KERNEL);
|
|
if (!data)
|
|
goto fail;
|
|
|
|
data->user_page = (void *)get_zeroed_page(GFP_KERNEL);
|
|
if (!data->user_page)
|
|
goto fail_user_page;
|
|
|
|
for (i = 0; i < nr_pages; i++) {
|
|
data->data_pages[i] = (void *)get_zeroed_page(GFP_KERNEL);
|
|
if (!data->data_pages[i])
|
|
goto fail_data_pages;
|
|
}
|
|
|
|
data->data_order = 0;
|
|
data->nr_pages = nr_pages;
|
|
|
|
return data;
|
|
|
|
fail_data_pages:
|
|
for (i--; i >= 0; i--)
|
|
free_page((unsigned long)data->data_pages[i]);
|
|
|
|
free_page((unsigned long)data->user_page);
|
|
|
|
fail_user_page:
|
|
kfree(data);
|
|
|
|
fail:
|
|
return NULL;
|
|
}
|
|
|
|
static void perf_mmap_free_page(unsigned long addr)
|
|
{
|
|
struct page *page = virt_to_page((void *)addr);
|
|
|
|
page->mapping = NULL;
|
|
__free_page(page);
|
|
}
|
|
|
|
static void perf_mmap_data_free(struct perf_mmap_data *data)
|
|
{
|
|
int i;
|
|
|
|
perf_mmap_free_page((unsigned long)data->user_page);
|
|
for (i = 0; i < data->nr_pages; i++)
|
|
perf_mmap_free_page((unsigned long)data->data_pages[i]);
|
|
}
|
|
|
|
#else
|
|
|
|
/*
|
|
* Back perf_mmap() with vmalloc memory.
|
|
*
|
|
* Required for architectures that have d-cache aliasing issues.
|
|
*/
|
|
|
|
static struct page *
|
|
perf_mmap_to_page(struct perf_mmap_data *data, unsigned long pgoff)
|
|
{
|
|
if (pgoff > (1UL << data->data_order))
|
|
return NULL;
|
|
|
|
return vmalloc_to_page((void *)data->user_page + pgoff * PAGE_SIZE);
|
|
}
|
|
|
|
static void perf_mmap_unmark_page(void *addr)
|
|
{
|
|
struct page *page = vmalloc_to_page(addr);
|
|
|
|
page->mapping = NULL;
|
|
}
|
|
|
|
static void perf_mmap_data_free_work(struct work_struct *work)
|
|
{
|
|
struct perf_mmap_data *data;
|
|
void *base;
|
|
int i, nr;
|
|
|
|
data = container_of(work, struct perf_mmap_data, work);
|
|
nr = 1 << data->data_order;
|
|
|
|
base = data->user_page;
|
|
for (i = 0; i < nr + 1; i++)
|
|
perf_mmap_unmark_page(base + (i * PAGE_SIZE));
|
|
|
|
vfree(base);
|
|
}
|
|
|
|
static void perf_mmap_data_free(struct perf_mmap_data *data)
|
|
{
|
|
schedule_work(&data->work);
|
|
}
|
|
|
|
static struct perf_mmap_data *
|
|
perf_mmap_data_alloc(struct perf_event *event, int nr_pages)
|
|
{
|
|
struct perf_mmap_data *data;
|
|
unsigned long size;
|
|
void *all_buf;
|
|
|
|
WARN_ON(atomic_read(&event->mmap_count));
|
|
|
|
size = sizeof(struct perf_mmap_data);
|
|
size += sizeof(void *);
|
|
|
|
data = kzalloc(size, GFP_KERNEL);
|
|
if (!data)
|
|
goto fail;
|
|
|
|
INIT_WORK(&data->work, perf_mmap_data_free_work);
|
|
|
|
all_buf = vmalloc_user((nr_pages + 1) * PAGE_SIZE);
|
|
if (!all_buf)
|
|
goto fail_all_buf;
|
|
|
|
data->user_page = all_buf;
|
|
data->data_pages[0] = all_buf + PAGE_SIZE;
|
|
data->data_order = ilog2(nr_pages);
|
|
data->nr_pages = 1;
|
|
|
|
return data;
|
|
|
|
fail_all_buf:
|
|
kfree(data);
|
|
|
|
fail:
|
|
return NULL;
|
|
}
|
|
|
|
#endif
|
|
|
|
static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
|
|
{
|
|
struct perf_event *event = vma->vm_file->private_data;
|
|
struct perf_mmap_data *data;
|
|
int ret = VM_FAULT_SIGBUS;
|
|
|
|
if (vmf->flags & FAULT_FLAG_MKWRITE) {
|
|
if (vmf->pgoff == 0)
|
|
ret = 0;
|
|
return ret;
|
|
}
|
|
|
|
rcu_read_lock();
|
|
data = rcu_dereference(event->data);
|
|
if (!data)
|
|
goto unlock;
|
|
|
|
if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
|
|
goto unlock;
|
|
|
|
vmf->page = perf_mmap_to_page(data, vmf->pgoff);
|
|
if (!vmf->page)
|
|
goto unlock;
|
|
|
|
get_page(vmf->page);
|
|
vmf->page->mapping = vma->vm_file->f_mapping;
|
|
vmf->page->index = vmf->pgoff;
|
|
|
|
ret = 0;
|
|
unlock:
|
|
rcu_read_unlock();
|
|
|
|
return ret;
|
|
}
|
|
|
|
static void
|
|
perf_mmap_data_init(struct perf_event *event, struct perf_mmap_data *data)
|
|
{
|
|
long max_size = perf_data_size(data);
|
|
|
|
atomic_set(&data->lock, -1);
|
|
|
|
if (event->attr.watermark) {
|
|
data->watermark = min_t(long, max_size,
|
|
event->attr.wakeup_watermark);
|
|
}
|
|
|
|
if (!data->watermark)
|
|
data->watermark = max_t(long, PAGE_SIZE, max_size / 2);
|
|
|
|
|
|
rcu_assign_pointer(event->data, data);
|
|
}
|
|
|
|
static void perf_mmap_data_free_rcu(struct rcu_head *rcu_head)
|
|
{
|
|
struct perf_mmap_data *data;
|
|
|
|
data = container_of(rcu_head, struct perf_mmap_data, rcu_head);
|
|
perf_mmap_data_free(data);
|
|
kfree(data);
|
|
}
|
|
|
|
static void perf_mmap_data_release(struct perf_event *event)
|
|
{
|
|
struct perf_mmap_data *data = event->data;
|
|
|
|
WARN_ON(atomic_read(&event->mmap_count));
|
|
|
|
rcu_assign_pointer(event->data, NULL);
|
|
call_rcu(&data->rcu_head, perf_mmap_data_free_rcu);
|
|
}
|
|
|
|
static void perf_mmap_open(struct vm_area_struct *vma)
|
|
{
|
|
struct perf_event *event = vma->vm_file->private_data;
|
|
|
|
atomic_inc(&event->mmap_count);
|
|
}
|
|
|
|
static void perf_mmap_close(struct vm_area_struct *vma)
|
|
{
|
|
struct perf_event *event = vma->vm_file->private_data;
|
|
|
|
WARN_ON_ONCE(event->ctx->parent_ctx);
|
|
if (atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) {
|
|
unsigned long size = perf_data_size(event->data);
|
|
struct user_struct *user = current_user();
|
|
|
|
atomic_long_sub((size >> PAGE_SHIFT) + 1, &user->locked_vm);
|
|
vma->vm_mm->locked_vm -= event->data->nr_locked;
|
|
perf_mmap_data_release(event);
|
|
mutex_unlock(&event->mmap_mutex);
|
|
}
|
|
}
|
|
|
|
static const struct vm_operations_struct perf_mmap_vmops = {
|
|
.open = perf_mmap_open,
|
|
.close = perf_mmap_close,
|
|
.fault = perf_mmap_fault,
|
|
.page_mkwrite = perf_mmap_fault,
|
|
};
|
|
|
|
static int perf_mmap(struct file *file, struct vm_area_struct *vma)
|
|
{
|
|
struct perf_event *event = file->private_data;
|
|
unsigned long user_locked, user_lock_limit;
|
|
struct user_struct *user = current_user();
|
|
unsigned long locked, lock_limit;
|
|
struct perf_mmap_data *data;
|
|
unsigned long vma_size;
|
|
unsigned long nr_pages;
|
|
long user_extra, extra;
|
|
int ret = 0;
|
|
|
|
if (!(vma->vm_flags & VM_SHARED))
|
|
return -EINVAL;
|
|
|
|
vma_size = vma->vm_end - vma->vm_start;
|
|
nr_pages = (vma_size / PAGE_SIZE) - 1;
|
|
|
|
/*
|
|
* If we have data pages ensure they're a power-of-two number, so we
|
|
* can do bitmasks instead of modulo.
|
|
*/
|
|
if (nr_pages != 0 && !is_power_of_2(nr_pages))
|
|
return -EINVAL;
|
|
|
|
if (vma_size != PAGE_SIZE * (1 + nr_pages))
|
|
return -EINVAL;
|
|
|
|
if (vma->vm_pgoff != 0)
|
|
return -EINVAL;
|
|
|
|
WARN_ON_ONCE(event->ctx->parent_ctx);
|
|
mutex_lock(&event->mmap_mutex);
|
|
if (event->output) {
|
|
ret = -EINVAL;
|
|
goto unlock;
|
|
}
|
|
|
|
if (atomic_inc_not_zero(&event->mmap_count)) {
|
|
if (nr_pages != event->data->nr_pages)
|
|
ret = -EINVAL;
|
|
goto unlock;
|
|
}
|
|
|
|
user_extra = nr_pages + 1;
|
|
user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
|
|
|
|
/*
|
|
* Increase the limit linearly with more CPUs:
|
|
*/
|
|
user_lock_limit *= num_online_cpus();
|
|
|
|
user_locked = atomic_long_read(&user->locked_vm) + user_extra;
|
|
|
|
extra = 0;
|
|
if (user_locked > user_lock_limit)
|
|
extra = user_locked - user_lock_limit;
|
|
|
|
lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
|
|
lock_limit >>= PAGE_SHIFT;
|
|
locked = vma->vm_mm->locked_vm + extra;
|
|
|
|
if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
|
|
!capable(CAP_IPC_LOCK)) {
|
|
ret = -EPERM;
|
|
goto unlock;
|
|
}
|
|
|
|
WARN_ON(event->data);
|
|
|
|
data = perf_mmap_data_alloc(event, nr_pages);
|
|
ret = -ENOMEM;
|
|
if (!data)
|
|
goto unlock;
|
|
|
|
ret = 0;
|
|
perf_mmap_data_init(event, data);
|
|
|
|
atomic_set(&event->mmap_count, 1);
|
|
atomic_long_add(user_extra, &user->locked_vm);
|
|
vma->vm_mm->locked_vm += extra;
|
|
event->data->nr_locked = extra;
|
|
if (vma->vm_flags & VM_WRITE)
|
|
event->data->writable = 1;
|
|
|
|
unlock:
|
|
mutex_unlock(&event->mmap_mutex);
|
|
|
|
vma->vm_flags |= VM_RESERVED;
|
|
vma->vm_ops = &perf_mmap_vmops;
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int perf_fasync(int fd, struct file *filp, int on)
|
|
{
|
|
struct inode *inode = filp->f_path.dentry->d_inode;
|
|
struct perf_event *event = filp->private_data;
|
|
int retval;
|
|
|
|
mutex_lock(&inode->i_mutex);
|
|
retval = fasync_helper(fd, filp, on, &event->fasync);
|
|
mutex_unlock(&inode->i_mutex);
|
|
|
|
if (retval < 0)
|
|
return retval;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct file_operations perf_fops = {
|
|
.release = perf_release,
|
|
.read = perf_read,
|
|
.poll = perf_poll,
|
|
.unlocked_ioctl = perf_ioctl,
|
|
.compat_ioctl = perf_ioctl,
|
|
.mmap = perf_mmap,
|
|
.fasync = perf_fasync,
|
|
};
|
|
|
|
/*
|
|
* Perf event wakeup
|
|
*
|
|
* If there's data, ensure we set the poll() state and publish everything
|
|
* to user-space before waking everybody up.
|
|
*/
|
|
|
|
void perf_event_wakeup(struct perf_event *event)
|
|
{
|
|
wake_up_all(&event->waitq);
|
|
|
|
if (event->pending_kill) {
|
|
kill_fasync(&event->fasync, SIGIO, event->pending_kill);
|
|
event->pending_kill = 0;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Pending wakeups
|
|
*
|
|
* Handle the case where we need to wakeup up from NMI (or rq->lock) context.
|
|
*
|
|
* The NMI bit means we cannot possibly take locks. Therefore, maintain a
|
|
* single linked list and use cmpxchg() to add entries lockless.
|
|
*/
|
|
|
|
static void perf_pending_event(struct perf_pending_entry *entry)
|
|
{
|
|
struct perf_event *event = container_of(entry,
|
|
struct perf_event, pending);
|
|
|
|
if (event->pending_disable) {
|
|
event->pending_disable = 0;
|
|
__perf_event_disable(event);
|
|
}
|
|
|
|
if (event->pending_wakeup) {
|
|
event->pending_wakeup = 0;
|
|
perf_event_wakeup(event);
|
|
}
|
|
}
|
|
|
|
#define PENDING_TAIL ((struct perf_pending_entry *)-1UL)
|
|
|
|
static DEFINE_PER_CPU(struct perf_pending_entry *, perf_pending_head) = {
|
|
PENDING_TAIL,
|
|
};
|
|
|
|
static void perf_pending_queue(struct perf_pending_entry *entry,
|
|
void (*func)(struct perf_pending_entry *))
|
|
{
|
|
struct perf_pending_entry **head;
|
|
|
|
if (cmpxchg(&entry->next, NULL, PENDING_TAIL) != NULL)
|
|
return;
|
|
|
|
entry->func = func;
|
|
|
|
head = &get_cpu_var(perf_pending_head);
|
|
|
|
do {
|
|
entry->next = *head;
|
|
} while (cmpxchg(head, entry->next, entry) != entry->next);
|
|
|
|
set_perf_event_pending();
|
|
|
|
put_cpu_var(perf_pending_head);
|
|
}
|
|
|
|
static int __perf_pending_run(void)
|
|
{
|
|
struct perf_pending_entry *list;
|
|
int nr = 0;
|
|
|
|
list = xchg(&__get_cpu_var(perf_pending_head), PENDING_TAIL);
|
|
while (list != PENDING_TAIL) {
|
|
void (*func)(struct perf_pending_entry *);
|
|
struct perf_pending_entry *entry = list;
|
|
|
|
list = list->next;
|
|
|
|
func = entry->func;
|
|
entry->next = NULL;
|
|
/*
|
|
* Ensure we observe the unqueue before we issue the wakeup,
|
|
* so that we won't be waiting forever.
|
|
* -- see perf_not_pending().
|
|
*/
|
|
smp_wmb();
|
|
|
|
func(entry);
|
|
nr++;
|
|
}
|
|
|
|
return nr;
|
|
}
|
|
|
|
static inline int perf_not_pending(struct perf_event *event)
|
|
{
|
|
/*
|
|
* If we flush on whatever cpu we run, there is a chance we don't
|
|
* need to wait.
|
|
*/
|
|
get_cpu();
|
|
__perf_pending_run();
|
|
put_cpu();
|
|
|
|
/*
|
|
* Ensure we see the proper queue state before going to sleep
|
|
* so that we do not miss the wakeup. -- see perf_pending_handle()
|
|
*/
|
|
smp_rmb();
|
|
return event->pending.next == NULL;
|
|
}
|
|
|
|
static void perf_pending_sync(struct perf_event *event)
|
|
{
|
|
wait_event(event->waitq, perf_not_pending(event));
|
|
}
|
|
|
|
void perf_event_do_pending(void)
|
|
{
|
|
__perf_pending_run();
|
|
}
|
|
|
|
/*
|
|
* Callchain support -- arch specific
|
|
*/
|
|
|
|
__weak struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
|
|
{
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* Output
|
|
*/
|
|
static bool perf_output_space(struct perf_mmap_data *data, unsigned long tail,
|
|
unsigned long offset, unsigned long head)
|
|
{
|
|
unsigned long mask;
|
|
|
|
if (!data->writable)
|
|
return true;
|
|
|
|
mask = perf_data_size(data) - 1;
|
|
|
|
offset = (offset - tail) & mask;
|
|
head = (head - tail) & mask;
|
|
|
|
if ((int)(head - offset) < 0)
|
|
return false;
|
|
|
|
return true;
|
|
}
|
|
|
|
static void perf_output_wakeup(struct perf_output_handle *handle)
|
|
{
|
|
atomic_set(&handle->data->poll, POLL_IN);
|
|
|
|
if (handle->nmi) {
|
|
handle->event->pending_wakeup = 1;
|
|
perf_pending_queue(&handle->event->pending,
|
|
perf_pending_event);
|
|
} else
|
|
perf_event_wakeup(handle->event);
|
|
}
|
|
|
|
/*
|
|
* Curious locking construct.
|
|
*
|
|
* We need to ensure a later event_id doesn't publish a head when a former
|
|
* event_id isn't done writing. However since we need to deal with NMIs we
|
|
* cannot fully serialize things.
|
|
*
|
|
* What we do is serialize between CPUs so we only have to deal with NMI
|
|
* nesting on a single CPU.
|
|
*
|
|
* We only publish the head (and generate a wakeup) when the outer-most
|
|
* event_id completes.
|
|
*/
|
|
static void perf_output_lock(struct perf_output_handle *handle)
|
|
{
|
|
struct perf_mmap_data *data = handle->data;
|
|
int cpu;
|
|
|
|
handle->locked = 0;
|
|
|
|
local_irq_save(handle->flags);
|
|
cpu = smp_processor_id();
|
|
|
|
if (in_nmi() && atomic_read(&data->lock) == cpu)
|
|
return;
|
|
|
|
while (atomic_cmpxchg(&data->lock, -1, cpu) != -1)
|
|
cpu_relax();
|
|
|
|
handle->locked = 1;
|
|
}
|
|
|
|
static void perf_output_unlock(struct perf_output_handle *handle)
|
|
{
|
|
struct perf_mmap_data *data = handle->data;
|
|
unsigned long head;
|
|
int cpu;
|
|
|
|
data->done_head = data->head;
|
|
|
|
if (!handle->locked)
|
|
goto out;
|
|
|
|
again:
|
|
/*
|
|
* The xchg implies a full barrier that ensures all writes are done
|
|
* before we publish the new head, matched by a rmb() in userspace when
|
|
* reading this position.
|
|
*/
|
|
while ((head = atomic_long_xchg(&data->done_head, 0)))
|
|
data->user_page->data_head = head;
|
|
|
|
/*
|
|
* NMI can happen here, which means we can miss a done_head update.
|
|
*/
|
|
|
|
cpu = atomic_xchg(&data->lock, -1);
|
|
WARN_ON_ONCE(cpu != smp_processor_id());
|
|
|
|
/*
|
|
* Therefore we have to validate we did not indeed do so.
|
|
*/
|
|
if (unlikely(atomic_long_read(&data->done_head))) {
|
|
/*
|
|
* Since we had it locked, we can lock it again.
|
|
*/
|
|
while (atomic_cmpxchg(&data->lock, -1, cpu) != -1)
|
|
cpu_relax();
|
|
|
|
goto again;
|
|
}
|
|
|
|
if (atomic_xchg(&data->wakeup, 0))
|
|
perf_output_wakeup(handle);
|
|
out:
|
|
local_irq_restore(handle->flags);
|
|
}
|
|
|
|
void perf_output_copy(struct perf_output_handle *handle,
|
|
const void *buf, unsigned int len)
|
|
{
|
|
unsigned int pages_mask;
|
|
unsigned long offset;
|
|
unsigned int size;
|
|
void **pages;
|
|
|
|
offset = handle->offset;
|
|
pages_mask = handle->data->nr_pages - 1;
|
|
pages = handle->data->data_pages;
|
|
|
|
do {
|
|
unsigned long page_offset;
|
|
unsigned long page_size;
|
|
int nr;
|
|
|
|
nr = (offset >> PAGE_SHIFT) & pages_mask;
|
|
page_size = 1UL << (handle->data->data_order + PAGE_SHIFT);
|
|
page_offset = offset & (page_size - 1);
|
|
size = min_t(unsigned int, page_size - page_offset, len);
|
|
|
|
memcpy(pages[nr] + page_offset, buf, size);
|
|
|
|
len -= size;
|
|
buf += size;
|
|
offset += size;
|
|
} while (len);
|
|
|
|
handle->offset = offset;
|
|
|
|
/*
|
|
* Check we didn't copy past our reservation window, taking the
|
|
* possible unsigned int wrap into account.
|
|
*/
|
|
WARN_ON_ONCE(((long)(handle->head - handle->offset)) < 0);
|
|
}
|
|
|
|
int perf_output_begin(struct perf_output_handle *handle,
|
|
struct perf_event *event, unsigned int size,
|
|
int nmi, int sample)
|
|
{
|
|
struct perf_event *output_event;
|
|
struct perf_mmap_data *data;
|
|
unsigned long tail, offset, head;
|
|
int have_lost;
|
|
struct {
|
|
struct perf_event_header header;
|
|
u64 id;
|
|
u64 lost;
|
|
} lost_event;
|
|
|
|
rcu_read_lock();
|
|
/*
|
|
* For inherited events we send all the output towards the parent.
|
|
*/
|
|
if (event->parent)
|
|
event = event->parent;
|
|
|
|
output_event = rcu_dereference(event->output);
|
|
if (output_event)
|
|
event = output_event;
|
|
|
|
data = rcu_dereference(event->data);
|
|
if (!data)
|
|
goto out;
|
|
|
|
handle->data = data;
|
|
handle->event = event;
|
|
handle->nmi = nmi;
|
|
handle->sample = sample;
|
|
|
|
if (!data->nr_pages)
|
|
goto fail;
|
|
|
|
have_lost = atomic_read(&data->lost);
|
|
if (have_lost)
|
|
size += sizeof(lost_event);
|
|
|
|
perf_output_lock(handle);
|
|
|
|
do {
|
|
/*
|
|
* Userspace could choose to issue a mb() before updating the
|
|
* tail pointer. So that all reads will be completed before the
|
|
* write is issued.
|
|
*/
|
|
tail = ACCESS_ONCE(data->user_page->data_tail);
|
|
smp_rmb();
|
|
offset = head = atomic_long_read(&data->head);
|
|
head += size;
|
|
if (unlikely(!perf_output_space(data, tail, offset, head)))
|
|
goto fail;
|
|
} while (atomic_long_cmpxchg(&data->head, offset, head) != offset);
|
|
|
|
handle->offset = offset;
|
|
handle->head = head;
|
|
|
|
if (head - tail > data->watermark)
|
|
atomic_set(&data->wakeup, 1);
|
|
|
|
if (have_lost) {
|
|
lost_event.header.type = PERF_RECORD_LOST;
|
|
lost_event.header.misc = 0;
|
|
lost_event.header.size = sizeof(lost_event);
|
|
lost_event.id = event->id;
|
|
lost_event.lost = atomic_xchg(&data->lost, 0);
|
|
|
|
perf_output_put(handle, lost_event);
|
|
}
|
|
|
|
return 0;
|
|
|
|
fail:
|
|
atomic_inc(&data->lost);
|
|
perf_output_unlock(handle);
|
|
out:
|
|
rcu_read_unlock();
|
|
|
|
return -ENOSPC;
|
|
}
|
|
|
|
void perf_output_end(struct perf_output_handle *handle)
|
|
{
|
|
struct perf_event *event = handle->event;
|
|
struct perf_mmap_data *data = handle->data;
|
|
|
|
int wakeup_events = event->attr.wakeup_events;
|
|
|
|
if (handle->sample && wakeup_events) {
|
|
int events = atomic_inc_return(&data->events);
|
|
if (events >= wakeup_events) {
|
|
atomic_sub(wakeup_events, &data->events);
|
|
atomic_set(&data->wakeup, 1);
|
|
}
|
|
}
|
|
|
|
perf_output_unlock(handle);
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
|
|
{
|
|
/*
|
|
* only top level events have the pid namespace they were created in
|
|
*/
|
|
if (event->parent)
|
|
event = event->parent;
|
|
|
|
return task_tgid_nr_ns(p, event->ns);
|
|
}
|
|
|
|
static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
|
|
{
|
|
/*
|
|
* only top level events have the pid namespace they were created in
|
|
*/
|
|
if (event->parent)
|
|
event = event->parent;
|
|
|
|
return task_pid_nr_ns(p, event->ns);
|
|
}
|
|
|
|
static void perf_output_read_one(struct perf_output_handle *handle,
|
|
struct perf_event *event)
|
|
{
|
|
u64 read_format = event->attr.read_format;
|
|
u64 values[4];
|
|
int n = 0;
|
|
|
|
values[n++] = atomic64_read(&event->count);
|
|
if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
|
|
values[n++] = event->total_time_enabled +
|
|
atomic64_read(&event->child_total_time_enabled);
|
|
}
|
|
if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
|
|
values[n++] = event->total_time_running +
|
|
atomic64_read(&event->child_total_time_running);
|
|
}
|
|
if (read_format & PERF_FORMAT_ID)
|
|
values[n++] = primary_event_id(event);
|
|
|
|
perf_output_copy(handle, values, n * sizeof(u64));
|
|
}
|
|
|
|
/*
|
|
* XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
|
|
*/
|
|
static void perf_output_read_group(struct perf_output_handle *handle,
|
|
struct perf_event *event)
|
|
{
|
|
struct perf_event *leader = event->group_leader, *sub;
|
|
u64 read_format = event->attr.read_format;
|
|
u64 values[5];
|
|
int n = 0;
|
|
|
|
values[n++] = 1 + leader->nr_siblings;
|
|
|
|
if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
|
|
values[n++] = leader->total_time_enabled;
|
|
|
|
if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
|
|
values[n++] = leader->total_time_running;
|
|
|
|
if (leader != event)
|
|
leader->pmu->read(leader);
|
|
|
|
values[n++] = atomic64_read(&leader->count);
|
|
if (read_format & PERF_FORMAT_ID)
|
|
values[n++] = primary_event_id(leader);
|
|
|
|
perf_output_copy(handle, values, n * sizeof(u64));
|
|
|
|
list_for_each_entry(sub, &leader->sibling_list, group_entry) {
|
|
n = 0;
|
|
|
|
if (sub != event)
|
|
sub->pmu->read(sub);
|
|
|
|
values[n++] = atomic64_read(&sub->count);
|
|
if (read_format & PERF_FORMAT_ID)
|
|
values[n++] = primary_event_id(sub);
|
|
|
|
perf_output_copy(handle, values, n * sizeof(u64));
|
|
}
|
|
}
|
|
|
|
static void perf_output_read(struct perf_output_handle *handle,
|
|
struct perf_event *event)
|
|
{
|
|
if (event->attr.read_format & PERF_FORMAT_GROUP)
|
|
perf_output_read_group(handle, event);
|
|
else
|
|
perf_output_read_one(handle, event);
|
|
}
|
|
|
|
void perf_output_sample(struct perf_output_handle *handle,
|
|
struct perf_event_header *header,
|
|
struct perf_sample_data *data,
|
|
struct perf_event *event)
|
|
{
|
|
u64 sample_type = data->type;
|
|
|
|
perf_output_put(handle, *header);
|
|
|
|
if (sample_type & PERF_SAMPLE_IP)
|
|
perf_output_put(handle, data->ip);
|
|
|
|
if (sample_type & PERF_SAMPLE_TID)
|
|
perf_output_put(handle, data->tid_entry);
|
|
|
|
if (sample_type & PERF_SAMPLE_TIME)
|
|
perf_output_put(handle, data->time);
|
|
|
|
if (sample_type & PERF_SAMPLE_ADDR)
|
|
perf_output_put(handle, data->addr);
|
|
|
|
if (sample_type & PERF_SAMPLE_ID)
|
|
perf_output_put(handle, data->id);
|
|
|
|
if (sample_type & PERF_SAMPLE_STREAM_ID)
|
|
perf_output_put(handle, data->stream_id);
|
|
|
|
if (sample_type & PERF_SAMPLE_CPU)
|
|
perf_output_put(handle, data->cpu_entry);
|
|
|
|
if (sample_type & PERF_SAMPLE_PERIOD)
|
|
perf_output_put(handle, data->period);
|
|
|
|
if (sample_type & PERF_SAMPLE_READ)
|
|
perf_output_read(handle, event);
|
|
|
|
if (sample_type & PERF_SAMPLE_CALLCHAIN) {
|
|
if (data->callchain) {
|
|
int size = 1;
|
|
|
|
if (data->callchain)
|
|
size += data->callchain->nr;
|
|
|
|
size *= sizeof(u64);
|
|
|
|
perf_output_copy(handle, data->callchain, size);
|
|
} else {
|
|
u64 nr = 0;
|
|
perf_output_put(handle, nr);
|
|
}
|
|
}
|
|
|
|
if (sample_type & PERF_SAMPLE_RAW) {
|
|
if (data->raw) {
|
|
perf_output_put(handle, data->raw->size);
|
|
perf_output_copy(handle, data->raw->data,
|
|
data->raw->size);
|
|
} else {
|
|
struct {
|
|
u32 size;
|
|
u32 data;
|
|
} raw = {
|
|
.size = sizeof(u32),
|
|
.data = 0,
|
|
};
|
|
perf_output_put(handle, raw);
|
|
}
|
|
}
|
|
}
|
|
|
|
void perf_prepare_sample(struct perf_event_header *header,
|
|
struct perf_sample_data *data,
|
|
struct perf_event *event,
|
|
struct pt_regs *regs)
|
|
{
|
|
u64 sample_type = event->attr.sample_type;
|
|
|
|
data->type = sample_type;
|
|
|
|
header->type = PERF_RECORD_SAMPLE;
|
|
header->size = sizeof(*header);
|
|
|
|
header->misc = 0;
|
|
header->misc |= perf_misc_flags(regs);
|
|
|
|
if (sample_type & PERF_SAMPLE_IP) {
|
|
data->ip = perf_instruction_pointer(regs);
|
|
|
|
header->size += sizeof(data->ip);
|
|
}
|
|
|
|
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);
|
|
|
|
header->size += sizeof(data->tid_entry);
|
|
}
|
|
|
|
if (sample_type & PERF_SAMPLE_TIME) {
|
|
data->time = perf_clock();
|
|
|
|
header->size += sizeof(data->time);
|
|
}
|
|
|
|
if (sample_type & PERF_SAMPLE_ADDR)
|
|
header->size += sizeof(data->addr);
|
|
|
|
if (sample_type & PERF_SAMPLE_ID) {
|
|
data->id = primary_event_id(event);
|
|
|
|
header->size += sizeof(data->id);
|
|
}
|
|
|
|
if (sample_type & PERF_SAMPLE_STREAM_ID) {
|
|
data->stream_id = event->id;
|
|
|
|
header->size += sizeof(data->stream_id);
|
|
}
|
|
|
|
if (sample_type & PERF_SAMPLE_CPU) {
|
|
data->cpu_entry.cpu = raw_smp_processor_id();
|
|
data->cpu_entry.reserved = 0;
|
|
|
|
header->size += sizeof(data->cpu_entry);
|
|
}
|
|
|
|
if (sample_type & PERF_SAMPLE_PERIOD)
|
|
header->size += sizeof(data->period);
|
|
|
|
if (sample_type & PERF_SAMPLE_READ)
|
|
header->size += perf_event_read_size(event);
|
|
|
|
if (sample_type & PERF_SAMPLE_CALLCHAIN) {
|
|
int size = 1;
|
|
|
|
data->callchain = perf_callchain(regs);
|
|
|
|
if (data->callchain)
|
|
size += data->callchain->nr;
|
|
|
|
header->size += size * sizeof(u64);
|
|
}
|
|
|
|
if (sample_type & PERF_SAMPLE_RAW) {
|
|
int size = sizeof(u32);
|
|
|
|
if (data->raw)
|
|
size += data->raw->size;
|
|
else
|
|
size += sizeof(u32);
|
|
|
|
WARN_ON_ONCE(size & (sizeof(u64)-1));
|
|
header->size += size;
|
|
}
|
|
}
|
|
|
|
static void perf_event_output(struct perf_event *event, int nmi,
|
|
struct perf_sample_data *data,
|
|
struct pt_regs *regs)
|
|
{
|
|
struct perf_output_handle handle;
|
|
struct perf_event_header header;
|
|
|
|
perf_prepare_sample(&header, data, event, regs);
|
|
|
|
if (perf_output_begin(&handle, event, header.size, nmi, 1))
|
|
return;
|
|
|
|
perf_output_sample(&handle, &header, data, event);
|
|
|
|
perf_output_end(&handle);
|
|
}
|
|
|
|
/*
|
|
* 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_read_event read_event = {
|
|
.header = {
|
|
.type = PERF_RECORD_READ,
|
|
.misc = 0,
|
|
.size = sizeof(read_event) + perf_event_read_size(event),
|
|
},
|
|
.pid = perf_event_pid(event, task),
|
|
.tid = perf_event_tid(event, task),
|
|
};
|
|
int ret;
|
|
|
|
ret = perf_output_begin(&handle, event, read_event.header.size, 0, 0);
|
|
if (ret)
|
|
return;
|
|
|
|
perf_output_put(&handle, read_event);
|
|
perf_output_read(&handle, event);
|
|
|
|
perf_output_end(&handle);
|
|
}
|
|
|
|
/*
|
|
* task tracking -- fork/exit
|
|
*
|
|
* enabled by: attr.comm | attr.mmap | attr.task
|
|
*/
|
|
|
|
struct perf_task_event {
|
|
struct task_struct *task;
|
|
struct perf_event_context *task_ctx;
|
|
|
|
struct {
|
|
struct perf_event_header header;
|
|
|
|
u32 pid;
|
|
u32 ppid;
|
|
u32 tid;
|
|
u32 ptid;
|
|
u64 time;
|
|
} event_id;
|
|
};
|
|
|
|
static void perf_event_task_output(struct perf_event *event,
|
|
struct perf_task_event *task_event)
|
|
{
|
|
struct perf_output_handle handle;
|
|
int size;
|
|
struct task_struct *task = task_event->task;
|
|
int ret;
|
|
|
|
size = task_event->event_id.header.size;
|
|
ret = perf_output_begin(&handle, event, size, 0, 0);
|
|
|
|
if (ret)
|
|
return;
|
|
|
|
task_event->event_id.pid = perf_event_pid(event, task);
|
|
task_event->event_id.ppid = perf_event_pid(event, current);
|
|
|
|
task_event->event_id.tid = perf_event_tid(event, task);
|
|
task_event->event_id.ptid = perf_event_tid(event, current);
|
|
|
|
task_event->event_id.time = perf_clock();
|
|
|
|
perf_output_put(&handle, task_event->event_id);
|
|
|
|
perf_output_end(&handle);
|
|
}
|
|
|
|
static int perf_event_task_match(struct perf_event *event)
|
|
{
|
|
if (event->attr.comm || event->attr.mmap || event->attr.task)
|
|
return 1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void perf_event_task_ctx(struct perf_event_context *ctx,
|
|
struct perf_task_event *task_event)
|
|
{
|
|
struct perf_event *event;
|
|
|
|
if (system_state != SYSTEM_RUNNING || list_empty(&ctx->event_list))
|
|
return;
|
|
|
|
rcu_read_lock();
|
|
list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
|
|
if (perf_event_task_match(event))
|
|
perf_event_task_output(event, task_event);
|
|
}
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
static void perf_event_task_event(struct perf_task_event *task_event)
|
|
{
|
|
struct perf_cpu_context *cpuctx;
|
|
struct perf_event_context *ctx = task_event->task_ctx;
|
|
|
|
cpuctx = &get_cpu_var(perf_cpu_context);
|
|
perf_event_task_ctx(&cpuctx->ctx, task_event);
|
|
put_cpu_var(perf_cpu_context);
|
|
|
|
rcu_read_lock();
|
|
if (!ctx)
|
|
ctx = rcu_dereference(task_event->task->perf_event_ctxp);
|
|
if (ctx)
|
|
perf_event_task_ctx(ctx, task_event);
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
static void perf_event_task(struct task_struct *task,
|
|
struct perf_event_context *task_ctx,
|
|
int new)
|
|
{
|
|
struct perf_task_event task_event;
|
|
|
|
if (!atomic_read(&nr_comm_events) &&
|
|
!atomic_read(&nr_mmap_events) &&
|
|
!atomic_read(&nr_task_events))
|
|
return;
|
|
|
|
task_event = (struct perf_task_event){
|
|
.task = task,
|
|
.task_ctx = task_ctx,
|
|
.event_id = {
|
|
.header = {
|
|
.type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
|
|
.misc = 0,
|
|
.size = sizeof(task_event.event_id),
|
|
},
|
|
/* .pid */
|
|
/* .ppid */
|
|
/* .tid */
|
|
/* .ptid */
|
|
},
|
|
};
|
|
|
|
perf_event_task_event(&task_event);
|
|
}
|
|
|
|
void perf_event_fork(struct task_struct *task)
|
|
{
|
|
perf_event_task(task, NULL, 1);
|
|
}
|
|
|
|
/*
|
|
* comm tracking
|
|
*/
|
|
|
|
struct perf_comm_event {
|
|
struct task_struct *task;
|
|
char *comm;
|
|
int comm_size;
|
|
|
|
struct {
|
|
struct perf_event_header header;
|
|
|
|
u32 pid;
|
|
u32 tid;
|
|
} event_id;
|
|
};
|
|
|
|
static void perf_event_comm_output(struct perf_event *event,
|
|
struct perf_comm_event *comm_event)
|
|
{
|
|
struct perf_output_handle handle;
|
|
int size = comm_event->event_id.header.size;
|
|
int ret = perf_output_begin(&handle, event, size, 0, 0);
|
|
|
|
if (ret)
|
|
return;
|
|
|
|
comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
|
|
comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
|
|
|
|
perf_output_put(&handle, comm_event->event_id);
|
|
perf_output_copy(&handle, comm_event->comm,
|
|
comm_event->comm_size);
|
|
perf_output_end(&handle);
|
|
}
|
|
|
|
static int perf_event_comm_match(struct perf_event *event)
|
|
{
|
|
if (event->attr.comm)
|
|
return 1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void perf_event_comm_ctx(struct perf_event_context *ctx,
|
|
struct perf_comm_event *comm_event)
|
|
{
|
|
struct perf_event *event;
|
|
|
|
if (system_state != SYSTEM_RUNNING || list_empty(&ctx->event_list))
|
|
return;
|
|
|
|
rcu_read_lock();
|
|
list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
|
|
if (perf_event_comm_match(event))
|
|
perf_event_comm_output(event, comm_event);
|
|
}
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
static void perf_event_comm_event(struct perf_comm_event *comm_event)
|
|
{
|
|
struct perf_cpu_context *cpuctx;
|
|
struct perf_event_context *ctx;
|
|
unsigned int size;
|
|
char comm[TASK_COMM_LEN];
|
|
|
|
memset(comm, 0, sizeof(comm));
|
|
strncpy(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;
|
|
|
|
cpuctx = &get_cpu_var(perf_cpu_context);
|
|
perf_event_comm_ctx(&cpuctx->ctx, comm_event);
|
|
put_cpu_var(perf_cpu_context);
|
|
|
|
rcu_read_lock();
|
|
/*
|
|
* doesn't really matter which of the child contexts the
|
|
* events ends up in.
|
|
*/
|
|
ctx = rcu_dereference(current->perf_event_ctxp);
|
|
if (ctx)
|
|
perf_event_comm_ctx(ctx, comm_event);
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
void perf_event_comm(struct task_struct *task)
|
|
{
|
|
struct perf_comm_event comm_event;
|
|
|
|
if (task->perf_event_ctxp)
|
|
perf_event_enable_on_exec(task);
|
|
|
|
if (!atomic_read(&nr_comm_events))
|
|
return;
|
|
|
|
comm_event = (struct perf_comm_event){
|
|
.task = task,
|
|
/* .comm */
|
|
/* .comm_size */
|
|
.event_id = {
|
|
.header = {
|
|
.type = PERF_RECORD_COMM,
|
|
.misc = 0,
|
|
/* .size */
|
|
},
|
|
/* .pid */
|
|
/* .tid */
|
|
},
|
|
};
|
|
|
|
perf_event_comm_event(&comm_event);
|
|
}
|
|
|
|
/*
|
|
* mmap tracking
|
|
*/
|
|
|
|
struct perf_mmap_event {
|
|
struct vm_area_struct *vma;
|
|
|
|
const char *file_name;
|
|
int file_size;
|
|
|
|
struct {
|
|
struct perf_event_header header;
|
|
|
|
u32 pid;
|
|
u32 tid;
|
|
u64 start;
|
|
u64 len;
|
|
u64 pgoff;
|
|
} event_id;
|
|
};
|
|
|
|
static void perf_event_mmap_output(struct perf_event *event,
|
|
struct perf_mmap_event *mmap_event)
|
|
{
|
|
struct perf_output_handle handle;
|
|
int size = mmap_event->event_id.header.size;
|
|
int ret = perf_output_begin(&handle, event, size, 0, 0);
|
|
|
|
if (ret)
|
|
return;
|
|
|
|
mmap_event->event_id.pid = perf_event_pid(event, current);
|
|
mmap_event->event_id.tid = perf_event_tid(event, current);
|
|
|
|
perf_output_put(&handle, mmap_event->event_id);
|
|
perf_output_copy(&handle, mmap_event->file_name,
|
|
mmap_event->file_size);
|
|
perf_output_end(&handle);
|
|
}
|
|
|
|
static int perf_event_mmap_match(struct perf_event *event,
|
|
struct perf_mmap_event *mmap_event)
|
|
{
|
|
if (event->attr.mmap)
|
|
return 1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void perf_event_mmap_ctx(struct perf_event_context *ctx,
|
|
struct perf_mmap_event *mmap_event)
|
|
{
|
|
struct perf_event *event;
|
|
|
|
if (system_state != SYSTEM_RUNNING || list_empty(&ctx->event_list))
|
|
return;
|
|
|
|
rcu_read_lock();
|
|
list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
|
|
if (perf_event_mmap_match(event, mmap_event))
|
|
perf_event_mmap_output(event, mmap_event);
|
|
}
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
|
|
{
|
|
struct perf_cpu_context *cpuctx;
|
|
struct perf_event_context *ctx;
|
|
struct vm_area_struct *vma = mmap_event->vma;
|
|
struct file *file = vma->vm_file;
|
|
unsigned int size;
|
|
char tmp[16];
|
|
char *buf = NULL;
|
|
const char *name;
|
|
|
|
memset(tmp, 0, sizeof(tmp));
|
|
|
|
if (file) {
|
|
/*
|
|
* d_path works from the end of the buffer backwards, so we
|
|
* need to add enough zero bytes after the string to handle
|
|
* the 64bit alignment we do later.
|
|
*/
|
|
buf = kzalloc(PATH_MAX + sizeof(u64), GFP_KERNEL);
|
|
if (!buf) {
|
|
name = strncpy(tmp, "//enomem", sizeof(tmp));
|
|
goto got_name;
|
|
}
|
|
name = d_path(&file->f_path, buf, PATH_MAX);
|
|
if (IS_ERR(name)) {
|
|
name = strncpy(tmp, "//toolong", sizeof(tmp));
|
|
goto got_name;
|
|
}
|
|
} else {
|
|
if (arch_vma_name(mmap_event->vma)) {
|
|
name = strncpy(tmp, arch_vma_name(mmap_event->vma),
|
|
sizeof(tmp));
|
|
goto got_name;
|
|
}
|
|
|
|
if (!vma->vm_mm) {
|
|
name = strncpy(tmp, "[vdso]", sizeof(tmp));
|
|
goto got_name;
|
|
}
|
|
|
|
name = strncpy(tmp, "//anon", sizeof(tmp));
|
|
goto got_name;
|
|
}
|
|
|
|
got_name:
|
|
size = ALIGN(strlen(name)+1, sizeof(u64));
|
|
|
|
mmap_event->file_name = name;
|
|
mmap_event->file_size = size;
|
|
|
|
mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
|
|
|
|
cpuctx = &get_cpu_var(perf_cpu_context);
|
|
perf_event_mmap_ctx(&cpuctx->ctx, mmap_event);
|
|
put_cpu_var(perf_cpu_context);
|
|
|
|
rcu_read_lock();
|
|
/*
|
|
* doesn't really matter which of the child contexts the
|
|
* events ends up in.
|
|
*/
|
|
ctx = rcu_dereference(current->perf_event_ctxp);
|
|
if (ctx)
|
|
perf_event_mmap_ctx(ctx, mmap_event);
|
|
rcu_read_unlock();
|
|
|
|
kfree(buf);
|
|
}
|
|
|
|
void __perf_event_mmap(struct vm_area_struct *vma)
|
|
{
|
|
struct perf_mmap_event mmap_event;
|
|
|
|
if (!atomic_read(&nr_mmap_events))
|
|
return;
|
|
|
|
mmap_event = (struct perf_mmap_event){
|
|
.vma = vma,
|
|
/* .file_name */
|
|
/* .file_size */
|
|
.event_id = {
|
|
.header = {
|
|
.type = PERF_RECORD_MMAP,
|
|
.misc = 0,
|
|
/* .size */
|
|
},
|
|
/* .pid */
|
|
/* .tid */
|
|
.start = vma->vm_start,
|
|
.len = vma->vm_end - vma->vm_start,
|
|
.pgoff = vma->vm_pgoff,
|
|
},
|
|
};
|
|
|
|
perf_event_mmap_event(&mmap_event);
|
|
}
|
|
|
|
/*
|
|
* IRQ throttle logging
|
|
*/
|
|
|
|
static void perf_log_throttle(struct perf_event *event, int enable)
|
|
{
|
|
struct perf_output_handle handle;
|
|
int ret;
|
|
|
|
struct {
|
|
struct perf_event_header header;
|
|
u64 time;
|
|
u64 id;
|
|
u64 stream_id;
|
|
} throttle_event = {
|
|
.header = {
|
|
.type = PERF_RECORD_THROTTLE,
|
|
.misc = 0,
|
|
.size = sizeof(throttle_event),
|
|
},
|
|
.time = perf_clock(),
|
|
.id = primary_event_id(event),
|
|
.stream_id = event->id,
|
|
};
|
|
|
|
if (enable)
|
|
throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
|
|
|
|
ret = perf_output_begin(&handle, event, sizeof(throttle_event), 1, 0);
|
|
if (ret)
|
|
return;
|
|
|
|
perf_output_put(&handle, throttle_event);
|
|
perf_output_end(&handle);
|
|
}
|
|
|
|
/*
|
|
* Generic event overflow handling, sampling.
|
|
*/
|
|
|
|
static int __perf_event_overflow(struct perf_event *event, int nmi,
|
|
int throttle, struct perf_sample_data *data,
|
|
struct pt_regs *regs)
|
|
{
|
|
int events = atomic_read(&event->event_limit);
|
|
struct hw_perf_event *hwc = &event->hw;
|
|
int ret = 0;
|
|
|
|
throttle = (throttle && event->pmu->unthrottle != NULL);
|
|
|
|
if (!throttle) {
|
|
hwc->interrupts++;
|
|
} else {
|
|
if (hwc->interrupts != MAX_INTERRUPTS) {
|
|
hwc->interrupts++;
|
|
if (HZ * hwc->interrupts >
|
|
(u64)sysctl_perf_event_sample_rate) {
|
|
hwc->interrupts = MAX_INTERRUPTS;
|
|
perf_log_throttle(event, 0);
|
|
ret = 1;
|
|
}
|
|
} else {
|
|
/*
|
|
* Keep re-disabling events even though on the previous
|
|
* pass we disabled it - just in case we raced with a
|
|
* sched-in and the event got enabled again:
|
|
*/
|
|
ret = 1;
|
|
}
|
|
}
|
|
|
|
if (event->attr.freq) {
|
|
u64 now = perf_clock();
|
|
s64 delta = now - hwc->freq_stamp;
|
|
|
|
hwc->freq_stamp = now;
|
|
|
|
if (delta > 0 && delta < TICK_NSEC)
|
|
perf_adjust_period(event, NSEC_PER_SEC / (int)delta);
|
|
}
|
|
|
|
/*
|
|
* XXX event_limit might not quite work as expected on inherited
|
|
* events
|
|
*/
|
|
|
|
event->pending_kill = POLL_IN;
|
|
if (events && atomic_dec_and_test(&event->event_limit)) {
|
|
ret = 1;
|
|
event->pending_kill = POLL_HUP;
|
|
if (nmi) {
|
|
event->pending_disable = 1;
|
|
perf_pending_queue(&event->pending,
|
|
perf_pending_event);
|
|
} else
|
|
perf_event_disable(event);
|
|
}
|
|
|
|
perf_event_output(event, nmi, data, regs);
|
|
return ret;
|
|
}
|
|
|
|
int perf_event_overflow(struct perf_event *event, int nmi,
|
|
struct perf_sample_data *data,
|
|
struct pt_regs *regs)
|
|
{
|
|
return __perf_event_overflow(event, nmi, 1, data, regs);
|
|
}
|
|
|
|
/*
|
|
* Generic software event infrastructure
|
|
*/
|
|
|
|
/*
|
|
* We directly increment event->count and keep a second value in
|
|
* event->hw.period_left to count intervals. This period event
|
|
* is kept in the range [-sample_period, 0] so that we can use the
|
|
* sign as trigger.
|
|
*/
|
|
|
|
static u64 perf_swevent_set_period(struct perf_event *event)
|
|
{
|
|
struct hw_perf_event *hwc = &event->hw;
|
|
u64 period = hwc->last_period;
|
|
u64 nr, offset;
|
|
s64 old, val;
|
|
|
|
hwc->last_period = hwc->sample_period;
|
|
|
|
again:
|
|
old = val = atomic64_read(&hwc->period_left);
|
|
if (val < 0)
|
|
return 0;
|
|
|
|
nr = div64_u64(period + val, period);
|
|
offset = nr * period;
|
|
val -= offset;
|
|
if (atomic64_cmpxchg(&hwc->period_left, old, val) != old)
|
|
goto again;
|
|
|
|
return nr;
|
|
}
|
|
|
|
static void perf_swevent_overflow(struct perf_event *event,
|
|
int nmi, struct perf_sample_data *data,
|
|
struct pt_regs *regs)
|
|
{
|
|
struct hw_perf_event *hwc = &event->hw;
|
|
int throttle = 0;
|
|
u64 overflow;
|
|
|
|
data->period = event->hw.last_period;
|
|
overflow = perf_swevent_set_period(event);
|
|
|
|
if (hwc->interrupts == MAX_INTERRUPTS)
|
|
return;
|
|
|
|
for (; overflow; overflow--) {
|
|
if (__perf_event_overflow(event, nmi, throttle,
|
|
data, regs)) {
|
|
/*
|
|
* We inhibit the overflow from happening when
|
|
* hwc->interrupts == MAX_INTERRUPTS.
|
|
*/
|
|
break;
|
|
}
|
|
throttle = 1;
|
|
}
|
|
}
|
|
|
|
static void perf_swevent_unthrottle(struct perf_event *event)
|
|
{
|
|
/*
|
|
* Nothing to do, we already reset hwc->interrupts.
|
|
*/
|
|
}
|
|
|
|
static void perf_swevent_add(struct perf_event *event, u64 nr,
|
|
int nmi, struct perf_sample_data *data,
|
|
struct pt_regs *regs)
|
|
{
|
|
struct hw_perf_event *hwc = &event->hw;
|
|
|
|
atomic64_add(nr, &event->count);
|
|
|
|
if (!hwc->sample_period)
|
|
return;
|
|
|
|
if (!regs)
|
|
return;
|
|
|
|
if (!atomic64_add_negative(nr, &hwc->period_left))
|
|
perf_swevent_overflow(event, nmi, data, regs);
|
|
}
|
|
|
|
static int perf_swevent_is_counting(struct perf_event *event)
|
|
{
|
|
/*
|
|
* The event is active, we're good!
|
|
*/
|
|
if (event->state == PERF_EVENT_STATE_ACTIVE)
|
|
return 1;
|
|
|
|
/*
|
|
* The event is off/error, not counting.
|
|
*/
|
|
if (event->state != PERF_EVENT_STATE_INACTIVE)
|
|
return 0;
|
|
|
|
/*
|
|
* The event is inactive, if the context is active
|
|
* we're part of a group that didn't make it on the 'pmu',
|
|
* not counting.
|
|
*/
|
|
if (event->ctx->is_active)
|
|
return 0;
|
|
|
|
/*
|
|
* We're inactive and the context is too, this means the
|
|
* task is scheduled out, we're counting events that happen
|
|
* to us, like migration events.
|
|
*/
|
|
return 1;
|
|
}
|
|
|
|
static int perf_swevent_match(struct perf_event *event,
|
|
enum perf_type_id type,
|
|
u32 event_id, struct pt_regs *regs)
|
|
{
|
|
if (!perf_swevent_is_counting(event))
|
|
return 0;
|
|
|
|
if (event->attr.type != type)
|
|
return 0;
|
|
if (event->attr.config != event_id)
|
|
return 0;
|
|
|
|
if (regs) {
|
|
if (event->attr.exclude_user && user_mode(regs))
|
|
return 0;
|
|
|
|
if (event->attr.exclude_kernel && !user_mode(regs))
|
|
return 0;
|
|
}
|
|
|
|
return 1;
|
|
}
|
|
|
|
static void perf_swevent_ctx_event(struct perf_event_context *ctx,
|
|
enum perf_type_id type,
|
|
u32 event_id, u64 nr, int nmi,
|
|
struct perf_sample_data *data,
|
|
struct pt_regs *regs)
|
|
{
|
|
struct perf_event *event;
|
|
|
|
if (system_state != SYSTEM_RUNNING || list_empty(&ctx->event_list))
|
|
return;
|
|
|
|
rcu_read_lock();
|
|
list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
|
|
if (perf_swevent_match(event, type, event_id, regs))
|
|
perf_swevent_add(event, nr, nmi, data, regs);
|
|
}
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
static int *perf_swevent_recursion_context(struct perf_cpu_context *cpuctx)
|
|
{
|
|
if (in_nmi())
|
|
return &cpuctx->recursion[3];
|
|
|
|
if (in_irq())
|
|
return &cpuctx->recursion[2];
|
|
|
|
if (in_softirq())
|
|
return &cpuctx->recursion[1];
|
|
|
|
return &cpuctx->recursion[0];
|
|
}
|
|
|
|
static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
|
|
u64 nr, int nmi,
|
|
struct perf_sample_data *data,
|
|
struct pt_regs *regs)
|
|
{
|
|
struct perf_cpu_context *cpuctx = &get_cpu_var(perf_cpu_context);
|
|
int *recursion = perf_swevent_recursion_context(cpuctx);
|
|
struct perf_event_context *ctx;
|
|
|
|
if (*recursion)
|
|
goto out;
|
|
|
|
(*recursion)++;
|
|
barrier();
|
|
|
|
perf_swevent_ctx_event(&cpuctx->ctx, type, event_id,
|
|
nr, nmi, data, regs);
|
|
rcu_read_lock();
|
|
/*
|
|
* doesn't really matter which of the child contexts the
|
|
* events ends up in.
|
|
*/
|
|
ctx = rcu_dereference(current->perf_event_ctxp);
|
|
if (ctx)
|
|
perf_swevent_ctx_event(ctx, type, event_id, nr, nmi, data, regs);
|
|
rcu_read_unlock();
|
|
|
|
barrier();
|
|
(*recursion)--;
|
|
|
|
out:
|
|
put_cpu_var(perf_cpu_context);
|
|
}
|
|
|
|
void __perf_sw_event(u32 event_id, u64 nr, int nmi,
|
|
struct pt_regs *regs, u64 addr)
|
|
{
|
|
struct perf_sample_data data = {
|
|
.addr = addr,
|
|
};
|
|
|
|
do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, nmi,
|
|
&data, regs);
|
|
}
|
|
|
|
static void perf_swevent_read(struct perf_event *event)
|
|
{
|
|
}
|
|
|
|
static int perf_swevent_enable(struct perf_event *event)
|
|
{
|
|
struct hw_perf_event *hwc = &event->hw;
|
|
|
|
if (hwc->sample_period) {
|
|
hwc->last_period = hwc->sample_period;
|
|
perf_swevent_set_period(event);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static void perf_swevent_disable(struct perf_event *event)
|
|
{
|
|
}
|
|
|
|
static const struct pmu perf_ops_generic = {
|
|
.enable = perf_swevent_enable,
|
|
.disable = perf_swevent_disable,
|
|
.read = perf_swevent_read,
|
|
.unthrottle = perf_swevent_unthrottle,
|
|
};
|
|
|
|
/*
|
|
* 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);
|
|
event->pmu->read(event);
|
|
|
|
data.addr = 0;
|
|
regs = get_irq_regs();
|
|
/*
|
|
* In case we exclude kernel IPs or are somehow not in interrupt
|
|
* context, provide the next best thing, the user IP.
|
|
*/
|
|
if ((event->attr.exclude_kernel || !regs) &&
|
|
!event->attr.exclude_user)
|
|
regs = task_pt_regs(current);
|
|
|
|
if (regs) {
|
|
if (!(event->attr.exclude_idle && current->pid == 0))
|
|
if (perf_event_overflow(event, 0, &data, regs))
|
|
ret = HRTIMER_NORESTART;
|
|
}
|
|
|
|
period = max_t(u64, 10000, event->hw.sample_period);
|
|
hrtimer_forward_now(hrtimer, ns_to_ktime(period));
|
|
|
|
return ret;
|
|
}
|
|
|
|
static void perf_swevent_start_hrtimer(struct perf_event *event)
|
|
{
|
|
struct hw_perf_event *hwc = &event->hw;
|
|
|
|
hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
|
|
hwc->hrtimer.function = perf_swevent_hrtimer;
|
|
if (hwc->sample_period) {
|
|
u64 period;
|
|
|
|
if (hwc->remaining) {
|
|
if (hwc->remaining < 0)
|
|
period = 10000;
|
|
else
|
|
period = hwc->remaining;
|
|
hwc->remaining = 0;
|
|
} else {
|
|
period = max_t(u64, 10000, hwc->sample_period);
|
|
}
|
|
__hrtimer_start_range_ns(&hwc->hrtimer,
|
|
ns_to_ktime(period), 0,
|
|
HRTIMER_MODE_REL, 0);
|
|
}
|
|
}
|
|
|
|
static void perf_swevent_cancel_hrtimer(struct perf_event *event)
|
|
{
|
|
struct hw_perf_event *hwc = &event->hw;
|
|
|
|
if (hwc->sample_period) {
|
|
ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
|
|
hwc->remaining = ktime_to_ns(remaining);
|
|
|
|
hrtimer_cancel(&hwc->hrtimer);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Software event: cpu wall time clock
|
|
*/
|
|
|
|
static void cpu_clock_perf_event_update(struct perf_event *event)
|
|
{
|
|
int cpu = raw_smp_processor_id();
|
|
s64 prev;
|
|
u64 now;
|
|
|
|
now = cpu_clock(cpu);
|
|
prev = atomic64_read(&event->hw.prev_count);
|
|
atomic64_set(&event->hw.prev_count, now);
|
|
atomic64_add(now - prev, &event->count);
|
|
}
|
|
|
|
static int cpu_clock_perf_event_enable(struct perf_event *event)
|
|
{
|
|
struct hw_perf_event *hwc = &event->hw;
|
|
int cpu = raw_smp_processor_id();
|
|
|
|
atomic64_set(&hwc->prev_count, cpu_clock(cpu));
|
|
perf_swevent_start_hrtimer(event);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void cpu_clock_perf_event_disable(struct perf_event *event)
|
|
{
|
|
perf_swevent_cancel_hrtimer(event);
|
|
cpu_clock_perf_event_update(event);
|
|
}
|
|
|
|
static void cpu_clock_perf_event_read(struct perf_event *event)
|
|
{
|
|
cpu_clock_perf_event_update(event);
|
|
}
|
|
|
|
static const struct pmu perf_ops_cpu_clock = {
|
|
.enable = cpu_clock_perf_event_enable,
|
|
.disable = cpu_clock_perf_event_disable,
|
|
.read = cpu_clock_perf_event_read,
|
|
};
|
|
|
|
/*
|
|
* Software event: task time clock
|
|
*/
|
|
|
|
static void task_clock_perf_event_update(struct perf_event *event, u64 now)
|
|
{
|
|
u64 prev;
|
|
s64 delta;
|
|
|
|
prev = atomic64_xchg(&event->hw.prev_count, now);
|
|
delta = now - prev;
|
|
atomic64_add(delta, &event->count);
|
|
}
|
|
|
|
static int task_clock_perf_event_enable(struct perf_event *event)
|
|
{
|
|
struct hw_perf_event *hwc = &event->hw;
|
|
u64 now;
|
|
|
|
now = event->ctx->time;
|
|
|
|
atomic64_set(&hwc->prev_count, now);
|
|
|
|
perf_swevent_start_hrtimer(event);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void task_clock_perf_event_disable(struct perf_event *event)
|
|
{
|
|
perf_swevent_cancel_hrtimer(event);
|
|
task_clock_perf_event_update(event, event->ctx->time);
|
|
|
|
}
|
|
|
|
static void task_clock_perf_event_read(struct perf_event *event)
|
|
{
|
|
u64 time;
|
|
|
|
if (!in_nmi()) {
|
|
update_context_time(event->ctx);
|
|
time = event->ctx->time;
|
|
} else {
|
|
u64 now = perf_clock();
|
|
u64 delta = now - event->ctx->timestamp;
|
|
time = event->ctx->time + delta;
|
|
}
|
|
|
|
task_clock_perf_event_update(event, time);
|
|
}
|
|
|
|
static const struct pmu perf_ops_task_clock = {
|
|
.enable = task_clock_perf_event_enable,
|
|
.disable = task_clock_perf_event_disable,
|
|
.read = task_clock_perf_event_read,
|
|
};
|
|
|
|
#ifdef CONFIG_EVENT_PROFILE
|
|
void perf_tp_event(int event_id, u64 addr, u64 count, void *record,
|
|
int entry_size)
|
|
{
|
|
struct perf_raw_record raw = {
|
|
.size = entry_size,
|
|
.data = record,
|
|
};
|
|
|
|
struct perf_sample_data data = {
|
|
.addr = addr,
|
|
.raw = &raw,
|
|
};
|
|
|
|
struct pt_regs *regs = get_irq_regs();
|
|
|
|
if (!regs)
|
|
regs = task_pt_regs(current);
|
|
|
|
do_perf_sw_event(PERF_TYPE_TRACEPOINT, event_id, count, 1,
|
|
&data, regs);
|
|
}
|
|
EXPORT_SYMBOL_GPL(perf_tp_event);
|
|
|
|
extern int ftrace_profile_enable(int);
|
|
extern void ftrace_profile_disable(int);
|
|
|
|
static void tp_perf_event_destroy(struct perf_event *event)
|
|
{
|
|
ftrace_profile_disable(event->attr.config);
|
|
}
|
|
|
|
static const struct pmu *tp_perf_event_init(struct perf_event *event)
|
|
{
|
|
/*
|
|
* Raw tracepoint data is a severe data leak, only allow root to
|
|
* have these.
|
|
*/
|
|
if ((event->attr.sample_type & PERF_SAMPLE_RAW) &&
|
|
perf_paranoid_tracepoint_raw() &&
|
|
!capable(CAP_SYS_ADMIN))
|
|
return ERR_PTR(-EPERM);
|
|
|
|
if (ftrace_profile_enable(event->attr.config))
|
|
return NULL;
|
|
|
|
event->destroy = tp_perf_event_destroy;
|
|
|
|
return &perf_ops_generic;
|
|
}
|
|
#else
|
|
static const struct pmu *tp_perf_event_init(struct perf_event *event)
|
|
{
|
|
return NULL;
|
|
}
|
|
#endif
|
|
|
|
atomic_t 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);
|
|
|
|
atomic_dec(&perf_swevent_enabled[event_id]);
|
|
}
|
|
|
|
static const struct pmu *sw_perf_event_init(struct perf_event *event)
|
|
{
|
|
const struct pmu *pmu = NULL;
|
|
u64 event_id = event->attr.config;
|
|
|
|
/*
|
|
* Software events (currently) can't in general distinguish
|
|
* between user, kernel and hypervisor events.
|
|
* However, context switches and cpu migrations are considered
|
|
* to be kernel events, and page faults are never hypervisor
|
|
* events.
|
|
*/
|
|
switch (event_id) {
|
|
case PERF_COUNT_SW_CPU_CLOCK:
|
|
pmu = &perf_ops_cpu_clock;
|
|
|
|
break;
|
|
case PERF_COUNT_SW_TASK_CLOCK:
|
|
/*
|
|
* If the user instantiates this as a per-cpu event,
|
|
* use the cpu_clock event instead.
|
|
*/
|
|
if (event->ctx->task)
|
|
pmu = &perf_ops_task_clock;
|
|
else
|
|
pmu = &perf_ops_cpu_clock;
|
|
|
|
break;
|
|
case PERF_COUNT_SW_PAGE_FAULTS:
|
|
case PERF_COUNT_SW_PAGE_FAULTS_MIN:
|
|
case PERF_COUNT_SW_PAGE_FAULTS_MAJ:
|
|
case PERF_COUNT_SW_CONTEXT_SWITCHES:
|
|
case PERF_COUNT_SW_CPU_MIGRATIONS:
|
|
if (!event->parent) {
|
|
atomic_inc(&perf_swevent_enabled[event_id]);
|
|
event->destroy = sw_perf_event_destroy;
|
|
}
|
|
pmu = &perf_ops_generic;
|
|
break;
|
|
}
|
|
|
|
return pmu;
|
|
}
|
|
|
|
/*
|
|
* Allocate and initialize a event structure
|
|
*/
|
|
static struct perf_event *
|
|
perf_event_alloc(struct perf_event_attr *attr,
|
|
int cpu,
|
|
struct perf_event_context *ctx,
|
|
struct perf_event *group_leader,
|
|
struct perf_event *parent_event,
|
|
gfp_t gfpflags)
|
|
{
|
|
const struct pmu *pmu;
|
|
struct perf_event *event;
|
|
struct hw_perf_event *hwc;
|
|
long err;
|
|
|
|
event = kzalloc(sizeof(*event), gfpflags);
|
|
if (!event)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
/*
|
|
* Single events are their own group leaders, with an
|
|
* empty sibling list:
|
|
*/
|
|
if (!group_leader)
|
|
group_leader = event;
|
|
|
|
mutex_init(&event->child_mutex);
|
|
INIT_LIST_HEAD(&event->child_list);
|
|
|
|
INIT_LIST_HEAD(&event->group_entry);
|
|
INIT_LIST_HEAD(&event->event_entry);
|
|
INIT_LIST_HEAD(&event->sibling_list);
|
|
init_waitqueue_head(&event->waitq);
|
|
|
|
mutex_init(&event->mmap_mutex);
|
|
|
|
event->cpu = cpu;
|
|
event->attr = *attr;
|
|
event->group_leader = group_leader;
|
|
event->pmu = NULL;
|
|
event->ctx = ctx;
|
|
event->oncpu = -1;
|
|
|
|
event->parent = parent_event;
|
|
|
|
event->ns = get_pid_ns(current->nsproxy->pid_ns);
|
|
event->id = atomic64_inc_return(&perf_event_id);
|
|
|
|
event->state = PERF_EVENT_STATE_INACTIVE;
|
|
|
|
if (attr->disabled)
|
|
event->state = PERF_EVENT_STATE_OFF;
|
|
|
|
pmu = NULL;
|
|
|
|
hwc = &event->hw;
|
|
hwc->sample_period = attr->sample_period;
|
|
if (attr->freq && attr->sample_freq)
|
|
hwc->sample_period = 1;
|
|
hwc->last_period = hwc->sample_period;
|
|
|
|
atomic64_set(&hwc->period_left, hwc->sample_period);
|
|
|
|
/*
|
|
* we currently do not support PERF_FORMAT_GROUP on inherited events
|
|
*/
|
|
if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
|
|
goto done;
|
|
|
|
switch (attr->type) {
|
|
case PERF_TYPE_RAW:
|
|
case PERF_TYPE_HARDWARE:
|
|
case PERF_TYPE_HW_CACHE:
|
|
pmu = hw_perf_event_init(event);
|
|
break;
|
|
|
|
case PERF_TYPE_SOFTWARE:
|
|
pmu = sw_perf_event_init(event);
|
|
break;
|
|
|
|
case PERF_TYPE_TRACEPOINT:
|
|
pmu = tp_perf_event_init(event);
|
|
break;
|
|
|
|
default:
|
|
break;
|
|
}
|
|
done:
|
|
err = 0;
|
|
if (!pmu)
|
|
err = -EINVAL;
|
|
else if (IS_ERR(pmu))
|
|
err = PTR_ERR(pmu);
|
|
|
|
if (err) {
|
|
if (event->ns)
|
|
put_pid_ns(event->ns);
|
|
kfree(event);
|
|
return ERR_PTR(err);
|
|
}
|
|
|
|
event->pmu = pmu;
|
|
|
|
if (!event->parent) {
|
|
atomic_inc(&nr_events);
|
|
if (event->attr.mmap)
|
|
atomic_inc(&nr_mmap_events);
|
|
if (event->attr.comm)
|
|
atomic_inc(&nr_comm_events);
|
|
if (event->attr.task)
|
|
atomic_inc(&nr_task_events);
|
|
}
|
|
|
|
return event;
|
|
}
|
|
|
|
static int perf_copy_attr(struct perf_event_attr __user *uattr,
|
|
struct perf_event_attr *attr)
|
|
{
|
|
u32 size;
|
|
int ret;
|
|
|
|
if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
|
|
return -EFAULT;
|
|
|
|
/*
|
|
* zero the full structure, so that a short copy will be nice.
|
|
*/
|
|
memset(attr, 0, sizeof(*attr));
|
|
|
|
ret = get_user(size, &uattr->size);
|
|
if (ret)
|
|
return ret;
|
|
|
|
if (size > PAGE_SIZE) /* silly large */
|
|
goto err_size;
|
|
|
|
if (!size) /* abi compat */
|
|
size = PERF_ATTR_SIZE_VER0;
|
|
|
|
if (size < PERF_ATTR_SIZE_VER0)
|
|
goto err_size;
|
|
|
|
/*
|
|
* If we're handed a bigger struct than we know of,
|
|
* ensure all the unknown bits are 0 - i.e. new
|
|
* user-space does not rely on any kernel feature
|
|
* extensions we dont know about yet.
|
|
*/
|
|
if (size > sizeof(*attr)) {
|
|
unsigned char __user *addr;
|
|
unsigned char __user *end;
|
|
unsigned char val;
|
|
|
|
addr = (void __user *)uattr + sizeof(*attr);
|
|
end = (void __user *)uattr + size;
|
|
|
|
for (; addr < end; addr++) {
|
|
ret = get_user(val, addr);
|
|
if (ret)
|
|
return ret;
|
|
if (val)
|
|
goto err_size;
|
|
}
|
|
size = sizeof(*attr);
|
|
}
|
|
|
|
ret = copy_from_user(attr, uattr, size);
|
|
if (ret)
|
|
return -EFAULT;
|
|
|
|
/*
|
|
* If the type exists, the corresponding creation will verify
|
|
* the attr->config.
|
|
*/
|
|
if (attr->type >= PERF_TYPE_MAX)
|
|
return -EINVAL;
|
|
|
|
if (attr->__reserved_1 || 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;
|
|
|
|
out:
|
|
return ret;
|
|
|
|
err_size:
|
|
put_user(sizeof(*attr), &uattr->size);
|
|
ret = -E2BIG;
|
|
goto out;
|
|
}
|
|
|
|
int perf_event_set_output(struct perf_event *event, int output_fd)
|
|
{
|
|
struct perf_event *output_event = NULL;
|
|
struct file *output_file = NULL;
|
|
struct perf_event *old_output;
|
|
int fput_needed = 0;
|
|
int ret = -EINVAL;
|
|
|
|
if (!output_fd)
|
|
goto set;
|
|
|
|
output_file = fget_light(output_fd, &fput_needed);
|
|
if (!output_file)
|
|
return -EBADF;
|
|
|
|
if (output_file->f_op != &perf_fops)
|
|
goto out;
|
|
|
|
output_event = output_file->private_data;
|
|
|
|
/* Don't chain output fds */
|
|
if (output_event->output)
|
|
goto out;
|
|
|
|
/* Don't set an output fd when we already have an output channel */
|
|
if (event->data)
|
|
goto out;
|
|
|
|
atomic_long_inc(&output_file->f_count);
|
|
|
|
set:
|
|
mutex_lock(&event->mmap_mutex);
|
|
old_output = event->output;
|
|
rcu_assign_pointer(event->output, output_event);
|
|
mutex_unlock(&event->mmap_mutex);
|
|
|
|
if (old_output) {
|
|
/*
|
|
* we need to make sure no existing perf_output_*()
|
|
* is still referencing this event.
|
|
*/
|
|
synchronize_rcu();
|
|
fput(old_output->filp);
|
|
}
|
|
|
|
ret = 0;
|
|
out:
|
|
fput_light(output_file, fput_needed);
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* sys_perf_event_open - open a performance event, associate it to a task/cpu
|
|
*
|
|
* @attr_uptr: event_id type attributes for monitoring/sampling
|
|
* @pid: target pid
|
|
* @cpu: target cpu
|
|
* @group_fd: group leader event fd
|
|
*/
|
|
SYSCALL_DEFINE5(perf_event_open,
|
|
struct perf_event_attr __user *, attr_uptr,
|
|
pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
|
|
{
|
|
struct perf_event *event, *group_leader;
|
|
struct perf_event_attr attr;
|
|
struct perf_event_context *ctx;
|
|
struct file *event_file = NULL;
|
|
struct file *group_file = NULL;
|
|
int fput_needed = 0;
|
|
int fput_needed2 = 0;
|
|
int err;
|
|
|
|
/* for future expandability... */
|
|
if (flags & ~(PERF_FLAG_FD_NO_GROUP | PERF_FLAG_FD_OUTPUT))
|
|
return -EINVAL;
|
|
|
|
err = perf_copy_attr(attr_uptr, &attr);
|
|
if (err)
|
|
return err;
|
|
|
|
if (!attr.exclude_kernel) {
|
|
if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
|
|
return -EACCES;
|
|
}
|
|
|
|
if (attr.freq) {
|
|
if (attr.sample_freq > sysctl_perf_event_sample_rate)
|
|
return -EINVAL;
|
|
}
|
|
|
|
/*
|
|
* Get the target context (task or percpu):
|
|
*/
|
|
ctx = find_get_context(pid, cpu);
|
|
if (IS_ERR(ctx))
|
|
return PTR_ERR(ctx);
|
|
|
|
/*
|
|
* Look up the group leader (we will attach this event to it):
|
|
*/
|
|
group_leader = NULL;
|
|
if (group_fd != -1 && !(flags & PERF_FLAG_FD_NO_GROUP)) {
|
|
err = -EINVAL;
|
|
group_file = fget_light(group_fd, &fput_needed);
|
|
if (!group_file)
|
|
goto err_put_context;
|
|
if (group_file->f_op != &perf_fops)
|
|
goto err_put_context;
|
|
|
|
group_leader = group_file->private_data;
|
|
/*
|
|
* Do not allow a recursive hierarchy (this new sibling
|
|
* becoming part of another group-sibling):
|
|
*/
|
|
if (group_leader->group_leader != group_leader)
|
|
goto err_put_context;
|
|
/*
|
|
* Do not allow to attach to a group in a different
|
|
* task or CPU context:
|
|
*/
|
|
if (group_leader->ctx != ctx)
|
|
goto err_put_context;
|
|
/*
|
|
* Only a group leader can be exclusive or pinned
|
|
*/
|
|
if (attr.exclusive || attr.pinned)
|
|
goto err_put_context;
|
|
}
|
|
|
|
event = perf_event_alloc(&attr, cpu, ctx, group_leader,
|
|
NULL, GFP_KERNEL);
|
|
err = PTR_ERR(event);
|
|
if (IS_ERR(event))
|
|
goto err_put_context;
|
|
|
|
err = anon_inode_getfd("[perf_event]", &perf_fops, event, 0);
|
|
if (err < 0)
|
|
goto err_free_put_context;
|
|
|
|
event_file = fget_light(err, &fput_needed2);
|
|
if (!event_file)
|
|
goto err_free_put_context;
|
|
|
|
if (flags & PERF_FLAG_FD_OUTPUT) {
|
|
err = perf_event_set_output(event, group_fd);
|
|
if (err)
|
|
goto err_fput_free_put_context;
|
|
}
|
|
|
|
event->filp = event_file;
|
|
WARN_ON_ONCE(ctx->parent_ctx);
|
|
mutex_lock(&ctx->mutex);
|
|
perf_install_in_context(ctx, event, cpu);
|
|
++ctx->generation;
|
|
mutex_unlock(&ctx->mutex);
|
|
|
|
event->owner = current;
|
|
get_task_struct(current);
|
|
mutex_lock(¤t->perf_event_mutex);
|
|
list_add_tail(&event->owner_entry, ¤t->perf_event_list);
|
|
mutex_unlock(¤t->perf_event_mutex);
|
|
|
|
err_fput_free_put_context:
|
|
fput_light(event_file, fput_needed2);
|
|
|
|
err_free_put_context:
|
|
if (err < 0)
|
|
kfree(event);
|
|
|
|
err_put_context:
|
|
if (err < 0)
|
|
put_ctx(ctx);
|
|
|
|
fput_light(group_file, fput_needed);
|
|
|
|
return err;
|
|
}
|
|
|
|
/*
|
|
* inherit a event from parent task to child task:
|
|
*/
|
|
static struct perf_event *
|
|
inherit_event(struct perf_event *parent_event,
|
|
struct task_struct *parent,
|
|
struct perf_event_context *parent_ctx,
|
|
struct task_struct *child,
|
|
struct perf_event *group_leader,
|
|
struct perf_event_context *child_ctx)
|
|
{
|
|
struct perf_event *child_event;
|
|
|
|
/*
|
|
* 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_ctx,
|
|
group_leader, parent_event,
|
|
GFP_KERNEL);
|
|
if (IS_ERR(child_event))
|
|
return child_event;
|
|
get_ctx(child_ctx);
|
|
|
|
/*
|
|
* Make the child state follow the state of the parent event,
|
|
* not its attr.disabled bit. We hold the parent's mutex,
|
|
* so we won't race with perf_event_{en, dis}able_family.
|
|
*/
|
|
if (parent_event->state >= PERF_EVENT_STATE_INACTIVE)
|
|
child_event->state = PERF_EVENT_STATE_INACTIVE;
|
|
else
|
|
child_event->state = PERF_EVENT_STATE_OFF;
|
|
|
|
if (parent_event->attr.freq)
|
|
child_event->hw.sample_period = parent_event->hw.sample_period;
|
|
|
|
/*
|
|
* Link it up in the child's context:
|
|
*/
|
|
add_event_to_ctx(child_event, child_ctx);
|
|
|
|
/*
|
|
* Get a reference to the parent filp - we will fput it
|
|
* when the child event exits. This is safe to do because
|
|
* we are in the parent and we know that the filp still
|
|
* exists and has a nonzero count:
|
|
*/
|
|
atomic_long_inc(&parent_event->filp->f_count);
|
|
|
|
/*
|
|
* Link this into the parent event's child list
|
|
*/
|
|
WARN_ON_ONCE(parent_event->ctx->parent_ctx);
|
|
mutex_lock(&parent_event->child_mutex);
|
|
list_add_tail(&child_event->child_list, &parent_event->child_list);
|
|
mutex_unlock(&parent_event->child_mutex);
|
|
|
|
return child_event;
|
|
}
|
|
|
|
static int inherit_group(struct perf_event *parent_event,
|
|
struct task_struct *parent,
|
|
struct perf_event_context *parent_ctx,
|
|
struct task_struct *child,
|
|
struct perf_event_context *child_ctx)
|
|
{
|
|
struct perf_event *leader;
|
|
struct perf_event *sub;
|
|
struct perf_event *child_ctr;
|
|
|
|
leader = inherit_event(parent_event, parent, parent_ctx,
|
|
child, NULL, child_ctx);
|
|
if (IS_ERR(leader))
|
|
return PTR_ERR(leader);
|
|
list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
|
|
child_ctr = inherit_event(sub, parent, parent_ctx,
|
|
child, leader, child_ctx);
|
|
if (IS_ERR(child_ctr))
|
|
return PTR_ERR(child_ctr);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static void sync_child_event(struct perf_event *child_event,
|
|
struct task_struct *child)
|
|
{
|
|
struct perf_event *parent_event = child_event->parent;
|
|
u64 child_val;
|
|
|
|
if (child_event->attr.inherit_stat)
|
|
perf_event_read_event(child_event, child);
|
|
|
|
child_val = atomic64_read(&child_event->count);
|
|
|
|
/*
|
|
* Add back the child's count to the parent's count:
|
|
*/
|
|
atomic64_add(child_val, &parent_event->count);
|
|
atomic64_add(child_event->total_time_enabled,
|
|
&parent_event->child_total_time_enabled);
|
|
atomic64_add(child_event->total_time_running,
|
|
&parent_event->child_total_time_running);
|
|
|
|
/*
|
|
* Remove this event from the parent's list
|
|
*/
|
|
WARN_ON_ONCE(parent_event->ctx->parent_ctx);
|
|
mutex_lock(&parent_event->child_mutex);
|
|
list_del_init(&child_event->child_list);
|
|
mutex_unlock(&parent_event->child_mutex);
|
|
|
|
/*
|
|
* Release the parent event, if this was the last
|
|
* reference to it.
|
|
*/
|
|
fput(parent_event->filp);
|
|
}
|
|
|
|
static void
|
|
__perf_event_exit_task(struct perf_event *child_event,
|
|
struct perf_event_context *child_ctx,
|
|
struct task_struct *child)
|
|
{
|
|
struct perf_event *parent_event;
|
|
|
|
update_event_times(child_event);
|
|
perf_event_remove_from_context(child_event);
|
|
|
|
parent_event = child_event->parent;
|
|
/*
|
|
* It can happen that parent exits first, and has events
|
|
* that are still around due to the child reference. These
|
|
* events need to be zapped - but otherwise linger.
|
|
*/
|
|
if (parent_event) {
|
|
sync_child_event(child_event, child);
|
|
free_event(child_event);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* When a child task exits, feed back event values to parent events.
|
|
*/
|
|
void perf_event_exit_task(struct task_struct *child)
|
|
{
|
|
struct perf_event *child_event, *tmp;
|
|
struct perf_event_context *child_ctx;
|
|
unsigned long flags;
|
|
|
|
if (likely(!child->perf_event_ctxp)) {
|
|
perf_event_task(child, NULL, 0);
|
|
return;
|
|
}
|
|
|
|
local_irq_save(flags);
|
|
/*
|
|
* We can't reschedule here because interrupts are disabled,
|
|
* and either child is current or it is a task that can't be
|
|
* scheduled, so we are now safe from rescheduling changing
|
|
* our context.
|
|
*/
|
|
child_ctx = child->perf_event_ctxp;
|
|
__perf_event_task_sched_out(child_ctx);
|
|
|
|
/*
|
|
* Take the context lock here so that if find_get_context is
|
|
* reading child->perf_event_ctxp, we wait until it has
|
|
* incremented the context's refcount before we do put_ctx below.
|
|
*/
|
|
spin_lock(&child_ctx->lock);
|
|
child->perf_event_ctxp = NULL;
|
|
/*
|
|
* If this context is a clone; unclone it so it can't get
|
|
* swapped to another process while we're removing all
|
|
* the events from it.
|
|
*/
|
|
unclone_ctx(child_ctx);
|
|
spin_unlock_irqrestore(&child_ctx->lock, flags);
|
|
|
|
/*
|
|
* Report the task dead after unscheduling the events so that we
|
|
* won't get any samples after PERF_RECORD_EXIT. We can however still
|
|
* get a few PERF_RECORD_READ events.
|
|
*/
|
|
perf_event_task(child, child_ctx, 0);
|
|
|
|
/*
|
|
* We can recurse on the same lock type through:
|
|
*
|
|
* __perf_event_exit_task()
|
|
* sync_child_event()
|
|
* fput(parent_event->filp)
|
|
* perf_release()
|
|
* mutex_lock(&ctx->mutex)
|
|
*
|
|
* But since its the parent context it won't be the same instance.
|
|
*/
|
|
mutex_lock_nested(&child_ctx->mutex, SINGLE_DEPTH_NESTING);
|
|
|
|
again:
|
|
list_for_each_entry_safe(child_event, tmp, &child_ctx->group_list,
|
|
group_entry)
|
|
__perf_event_exit_task(child_event, child_ctx, child);
|
|
|
|
/*
|
|
* If the last event was a group event, it will have appended all
|
|
* its siblings to the list, but we obtained 'tmp' before that which
|
|
* will still point to the list head terminating the iteration.
|
|
*/
|
|
if (!list_empty(&child_ctx->group_list))
|
|
goto again;
|
|
|
|
mutex_unlock(&child_ctx->mutex);
|
|
|
|
put_ctx(child_ctx);
|
|
}
|
|
|
|
/*
|
|
* free an unexposed, unused context as created by inheritance by
|
|
* init_task below, used by fork() in case of fail.
|
|
*/
|
|
void perf_event_free_task(struct task_struct *task)
|
|
{
|
|
struct perf_event_context *ctx = task->perf_event_ctxp;
|
|
struct perf_event *event, *tmp;
|
|
|
|
if (!ctx)
|
|
return;
|
|
|
|
mutex_lock(&ctx->mutex);
|
|
again:
|
|
list_for_each_entry_safe(event, tmp, &ctx->group_list, group_entry) {
|
|
struct perf_event *parent = event->parent;
|
|
|
|
if (WARN_ON_ONCE(!parent))
|
|
continue;
|
|
|
|
mutex_lock(&parent->child_mutex);
|
|
list_del_init(&event->child_list);
|
|
mutex_unlock(&parent->child_mutex);
|
|
|
|
fput(parent->filp);
|
|
|
|
list_del_event(event, ctx);
|
|
free_event(event);
|
|
}
|
|
|
|
if (!list_empty(&ctx->group_list))
|
|
goto again;
|
|
|
|
mutex_unlock(&ctx->mutex);
|
|
|
|
put_ctx(ctx);
|
|
}
|
|
|
|
/*
|
|
* Initialize the perf_event context in task_struct
|
|
*/
|
|
int perf_event_init_task(struct task_struct *child)
|
|
{
|
|
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;
|
|
int ret = 0;
|
|
|
|
child->perf_event_ctxp = NULL;
|
|
|
|
mutex_init(&child->perf_event_mutex);
|
|
INIT_LIST_HEAD(&child->perf_event_list);
|
|
|
|
if (likely(!parent->perf_event_ctxp))
|
|
return 0;
|
|
|
|
/*
|
|
* 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 = kmalloc(sizeof(struct perf_event_context), GFP_KERNEL);
|
|
if (!child_ctx)
|
|
return -ENOMEM;
|
|
|
|
__perf_event_init_context(child_ctx, child);
|
|
child->perf_event_ctxp = child_ctx;
|
|
get_task_struct(child);
|
|
|
|
/*
|
|
* 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);
|
|
|
|
/*
|
|
* No need to check if parent_ctx != NULL here; since we saw
|
|
* it non-NULL earlier, the only reason for it to become NULL
|
|
* is if we exit, and since we're currently in the middle of
|
|
* a fork we can't be exiting at the same time.
|
|
*/
|
|
|
|
/*
|
|
* Lock the parent list. No need to lock the child - not PID
|
|
* hashed yet and not running, so nobody can access it.
|
|
*/
|
|
mutex_lock(&parent_ctx->mutex);
|
|
|
|
/*
|
|
* We dont have to disable NMIs - we are only looking at
|
|
* the list, not manipulating it:
|
|
*/
|
|
list_for_each_entry(event, &parent_ctx->group_list, group_entry) {
|
|
|
|
if (!event->attr.inherit) {
|
|
inherited_all = 0;
|
|
continue;
|
|
}
|
|
|
|
ret = inherit_group(event, parent, parent_ctx,
|
|
child, child_ctx);
|
|
if (ret) {
|
|
inherited_all = 0;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (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, it could get
|
|
* uncloned at any point, but that doesn't matter
|
|
* because the list of events and the generation
|
|
* count can't have changed since we took the mutex.
|
|
*/
|
|
cloned_ctx = rcu_dereference(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);
|
|
}
|
|
|
|
mutex_unlock(&parent_ctx->mutex);
|
|
|
|
perf_unpin_context(parent_ctx);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static void __cpuinit perf_event_init_cpu(int cpu)
|
|
{
|
|
struct perf_cpu_context *cpuctx;
|
|
|
|
cpuctx = &per_cpu(perf_cpu_context, cpu);
|
|
__perf_event_init_context(&cpuctx->ctx, NULL);
|
|
|
|
spin_lock(&perf_resource_lock);
|
|
cpuctx->max_pertask = perf_max_events - perf_reserved_percpu;
|
|
spin_unlock(&perf_resource_lock);
|
|
|
|
hw_perf_event_setup(cpu);
|
|
}
|
|
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
|
static void __perf_event_exit_cpu(void *info)
|
|
{
|
|
struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
|
|
struct perf_event_context *ctx = &cpuctx->ctx;
|
|
struct perf_event *event, *tmp;
|
|
|
|
list_for_each_entry_safe(event, tmp, &ctx->group_list, group_entry)
|
|
__perf_event_remove_from_context(event);
|
|
}
|
|
static void perf_event_exit_cpu(int cpu)
|
|
{
|
|
struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
|
|
struct perf_event_context *ctx = &cpuctx->ctx;
|
|
|
|
mutex_lock(&ctx->mutex);
|
|
smp_call_function_single(cpu, __perf_event_exit_cpu, NULL, 1);
|
|
mutex_unlock(&ctx->mutex);
|
|
}
|
|
#else
|
|
static inline void perf_event_exit_cpu(int cpu) { }
|
|
#endif
|
|
|
|
static int __cpuinit
|
|
perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
|
|
{
|
|
unsigned int cpu = (long)hcpu;
|
|
|
|
switch (action) {
|
|
|
|
case CPU_UP_PREPARE:
|
|
case CPU_UP_PREPARE_FROZEN:
|
|
perf_event_init_cpu(cpu);
|
|
break;
|
|
|
|
case CPU_ONLINE:
|
|
case CPU_ONLINE_FROZEN:
|
|
hw_perf_event_setup_online(cpu);
|
|
break;
|
|
|
|
case CPU_DOWN_PREPARE:
|
|
case CPU_DOWN_PREPARE_FROZEN:
|
|
perf_event_exit_cpu(cpu);
|
|
break;
|
|
|
|
default:
|
|
break;
|
|
}
|
|
|
|
return NOTIFY_OK;
|
|
}
|
|
|
|
/*
|
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* This has to have a higher priority than migration_notifier in sched.c.
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*/
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static struct notifier_block __cpuinitdata perf_cpu_nb = {
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.notifier_call = perf_cpu_notify,
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.priority = 20,
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};
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void __init perf_event_init(void)
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{
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perf_cpu_notify(&perf_cpu_nb, (unsigned long)CPU_UP_PREPARE,
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(void *)(long)smp_processor_id());
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perf_cpu_notify(&perf_cpu_nb, (unsigned long)CPU_ONLINE,
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(void *)(long)smp_processor_id());
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register_cpu_notifier(&perf_cpu_nb);
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}
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static ssize_t perf_show_reserve_percpu(struct sysdev_class *class, char *buf)
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{
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return sprintf(buf, "%d\n", perf_reserved_percpu);
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}
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static ssize_t
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perf_set_reserve_percpu(struct sysdev_class *class,
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const char *buf,
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size_t count)
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{
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struct perf_cpu_context *cpuctx;
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unsigned long val;
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int err, cpu, mpt;
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err = strict_strtoul(buf, 10, &val);
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if (err)
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return err;
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if (val > perf_max_events)
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return -EINVAL;
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spin_lock(&perf_resource_lock);
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perf_reserved_percpu = val;
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for_each_online_cpu(cpu) {
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cpuctx = &per_cpu(perf_cpu_context, cpu);
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spin_lock_irq(&cpuctx->ctx.lock);
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mpt = min(perf_max_events - cpuctx->ctx.nr_events,
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perf_max_events - perf_reserved_percpu);
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cpuctx->max_pertask = mpt;
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spin_unlock_irq(&cpuctx->ctx.lock);
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}
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spin_unlock(&perf_resource_lock);
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return count;
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}
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static ssize_t perf_show_overcommit(struct sysdev_class *class, char *buf)
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{
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return sprintf(buf, "%d\n", perf_overcommit);
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}
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static ssize_t
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perf_set_overcommit(struct sysdev_class *class, const char *buf, size_t count)
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{
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unsigned long val;
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int err;
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|
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err = strict_strtoul(buf, 10, &val);
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if (err)
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return err;
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if (val > 1)
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return -EINVAL;
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|
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spin_lock(&perf_resource_lock);
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perf_overcommit = val;
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spin_unlock(&perf_resource_lock);
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|
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return count;
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}
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|
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static SYSDEV_CLASS_ATTR(
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reserve_percpu,
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0644,
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perf_show_reserve_percpu,
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perf_set_reserve_percpu
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);
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static SYSDEV_CLASS_ATTR(
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overcommit,
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0644,
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perf_show_overcommit,
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perf_set_overcommit
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);
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|
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static struct attribute *perfclass_attrs[] = {
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&attr_reserve_percpu.attr,
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&attr_overcommit.attr,
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NULL
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};
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|
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static struct attribute_group perfclass_attr_group = {
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.attrs = perfclass_attrs,
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.name = "perf_events",
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};
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|
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static int __init perf_event_sysfs_init(void)
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{
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return sysfs_create_group(&cpu_sysdev_class.kset.kobj,
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&perfclass_attr_group);
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}
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device_initcall(perf_event_sysfs_init);
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