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@@ -1,425 +0,0 @@
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-/*
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- * kernel/time/timer_stats.c
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- *
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- * Collect timer usage statistics.
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- *
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- * Copyright(C) 2006, Red Hat, Inc., Ingo Molnar
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- * Copyright(C) 2006 Timesys Corp., Thomas Gleixner <tglx@timesys.com>
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- *
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- * timer_stats is based on timer_top, a similar functionality which was part of
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- * Con Kolivas dyntick patch set. It was developed by Daniel Petrini at the
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- * Instituto Nokia de Tecnologia - INdT - Manaus. timer_top's design was based
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- * on dynamic allocation of the statistics entries and linear search based
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- * lookup combined with a global lock, rather than the static array, hash
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- * and per-CPU locking which is used by timer_stats. It was written for the
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- * pre hrtimer kernel code and therefore did not take hrtimers into account.
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- * Nevertheless it provided the base for the timer_stats implementation and
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- * was a helpful source of inspiration. Kudos to Daniel and the Nokia folks
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- * for this effort.
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- *
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- * timer_top.c is
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- * Copyright (C) 2005 Instituto Nokia de Tecnologia - INdT - Manaus
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- * Written by Daniel Petrini <d.pensator@gmail.com>
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- * timer_top.c was released under the GNU General Public License version 2
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- *
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- * We export the addresses and counting of timer functions being called,
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- * the pid and cmdline from the owner process if applicable.
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- *
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- * Start/stop data collection:
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- * # echo [1|0] >/proc/timer_stats
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- *
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- * Display the information collected so far:
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- * # cat /proc/timer_stats
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- *
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- * This program is free software; you can redistribute it and/or modify
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- * it under the terms of the GNU General Public License version 2 as
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- * published by the Free Software Foundation.
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- */
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-
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-#include <linux/proc_fs.h>
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-#include <linux/module.h>
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-#include <linux/spinlock.h>
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-#include <linux/sched.h>
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-#include <linux/seq_file.h>
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-#include <linux/kallsyms.h>
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-
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-#include <linux/uaccess.h>
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-
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-/*
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- * This is our basic unit of interest: a timer expiry event identified
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- * by the timer, its start/expire functions and the PID of the task that
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- * started the timer. We count the number of times an event happens:
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- */
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-struct entry {
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- /*
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- * Hash list:
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- */
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- struct entry *next;
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-
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- /*
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- * Hash keys:
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- */
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- void *timer;
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- void *start_func;
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- void *expire_func;
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- pid_t pid;
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-
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- /*
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- * Number of timeout events:
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- */
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- unsigned long count;
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- u32 flags;
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-
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- /*
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- * We save the command-line string to preserve
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- * this information past task exit:
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- */
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- char comm[TASK_COMM_LEN + 1];
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-
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-} ____cacheline_aligned_in_smp;
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-
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-/*
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- * Spinlock protecting the tables - not taken during lookup:
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- */
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-static DEFINE_RAW_SPINLOCK(table_lock);
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-
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-/*
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- * Per-CPU lookup locks for fast hash lookup:
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- */
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-static DEFINE_PER_CPU(raw_spinlock_t, tstats_lookup_lock);
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-
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-/*
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- * Mutex to serialize state changes with show-stats activities:
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- */
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-static DEFINE_MUTEX(show_mutex);
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-
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-/*
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- * Collection status, active/inactive:
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- */
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-int __read_mostly timer_stats_active;
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-
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-/*
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- * Beginning/end timestamps of measurement:
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- */
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-static ktime_t time_start, time_stop;
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-
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-/*
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- * tstat entry structs only get allocated while collection is
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- * active and never freed during that time - this simplifies
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- * things quite a bit.
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- *
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- * They get freed when a new collection period is started.
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- */
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-#define MAX_ENTRIES_BITS 10
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-#define MAX_ENTRIES (1UL << MAX_ENTRIES_BITS)
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-
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-static unsigned long nr_entries;
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-static struct entry entries[MAX_ENTRIES];
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-
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-static atomic_t overflow_count;
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-
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-/*
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- * The entries are in a hash-table, for fast lookup:
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- */
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-#define TSTAT_HASH_BITS (MAX_ENTRIES_BITS - 1)
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-#define TSTAT_HASH_SIZE (1UL << TSTAT_HASH_BITS)
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-#define TSTAT_HASH_MASK (TSTAT_HASH_SIZE - 1)
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-
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-#define __tstat_hashfn(entry) \
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- (((unsigned long)(entry)->timer ^ \
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- (unsigned long)(entry)->start_func ^ \
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- (unsigned long)(entry)->expire_func ^ \
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- (unsigned long)(entry)->pid ) & TSTAT_HASH_MASK)
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-
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-#define tstat_hashentry(entry) (tstat_hash_table + __tstat_hashfn(entry))
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-
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-static struct entry *tstat_hash_table[TSTAT_HASH_SIZE] __read_mostly;
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-
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-static void reset_entries(void)
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-{
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- nr_entries = 0;
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- memset(entries, 0, sizeof(entries));
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- memset(tstat_hash_table, 0, sizeof(tstat_hash_table));
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- atomic_set(&overflow_count, 0);
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-}
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-
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-static struct entry *alloc_entry(void)
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-{
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- if (nr_entries >= MAX_ENTRIES)
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- return NULL;
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-
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- return entries + nr_entries++;
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-}
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-
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-static int match_entries(struct entry *entry1, struct entry *entry2)
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-{
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- return entry1->timer == entry2->timer &&
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- entry1->start_func == entry2->start_func &&
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- entry1->expire_func == entry2->expire_func &&
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- entry1->pid == entry2->pid;
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-}
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-
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-/*
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- * Look up whether an entry matching this item is present
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- * in the hash already. Must be called with irqs off and the
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- * lookup lock held:
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- */
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-static struct entry *tstat_lookup(struct entry *entry, char *comm)
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-{
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- struct entry **head, *curr, *prev;
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-
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- head = tstat_hashentry(entry);
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- curr = *head;
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-
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- /*
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- * The fastpath is when the entry is already hashed,
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- * we do this with the lookup lock held, but with the
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- * table lock not held:
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- */
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- while (curr) {
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- if (match_entries(curr, entry))
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- return curr;
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-
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- curr = curr->next;
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- }
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- /*
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- * Slowpath: allocate, set up and link a new hash entry:
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- */
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- prev = NULL;
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- curr = *head;
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-
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- raw_spin_lock(&table_lock);
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- /*
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- * Make sure we have not raced with another CPU:
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- */
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- while (curr) {
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- if (match_entries(curr, entry))
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- goto out_unlock;
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-
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- prev = curr;
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- curr = curr->next;
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- }
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-
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- curr = alloc_entry();
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- if (curr) {
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- *curr = *entry;
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- curr->count = 0;
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- curr->next = NULL;
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- memcpy(curr->comm, comm, TASK_COMM_LEN);
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-
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- smp_mb(); /* Ensure that curr is initialized before insert */
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-
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- if (prev)
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- prev->next = curr;
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- else
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- *head = curr;
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- }
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- out_unlock:
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- raw_spin_unlock(&table_lock);
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-
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- return curr;
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-}
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-
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-/**
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- * timer_stats_update_stats - Update the statistics for a timer.
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- * @timer: pointer to either a timer_list or a hrtimer
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- * @pid: the pid of the task which set up the timer
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- * @startf: pointer to the function which did the timer setup
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- * @timerf: pointer to the timer callback function of the timer
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- * @comm: name of the process which set up the timer
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- * @tflags: The flags field of the timer
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- *
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- * When the timer is already registered, then the event counter is
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- * incremented. Otherwise the timer is registered in a free slot.
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- */
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-void timer_stats_update_stats(void *timer, pid_t pid, void *startf,
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- void *timerf, char *comm, u32 tflags)
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-{
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- /*
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- * It doesn't matter which lock we take:
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- */
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- raw_spinlock_t *lock;
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- struct entry *entry, input;
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- unsigned long flags;
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-
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- if (likely(!timer_stats_active))
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- return;
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-
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- lock = &per_cpu(tstats_lookup_lock, raw_smp_processor_id());
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-
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- input.timer = timer;
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- input.start_func = startf;
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- input.expire_func = timerf;
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- input.pid = pid;
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- input.flags = tflags;
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-
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- raw_spin_lock_irqsave(lock, flags);
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- if (!timer_stats_active)
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- goto out_unlock;
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-
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- entry = tstat_lookup(&input, comm);
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- if (likely(entry))
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- entry->count++;
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- else
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- atomic_inc(&overflow_count);
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-
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- out_unlock:
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- raw_spin_unlock_irqrestore(lock, flags);
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-}
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-
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-static void print_name_offset(struct seq_file *m, unsigned long addr)
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-{
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- char symname[KSYM_NAME_LEN];
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-
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- if (lookup_symbol_name(addr, symname) < 0)
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- seq_printf(m, "<%p>", (void *)addr);
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- else
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- seq_printf(m, "%s", symname);
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-}
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-
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-static int tstats_show(struct seq_file *m, void *v)
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-{
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- struct timespec64 period;
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- struct entry *entry;
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- unsigned long ms;
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- long events = 0;
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- ktime_t time;
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- int i;
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-
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- mutex_lock(&show_mutex);
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- /*
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- * If still active then calculate up to now:
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- */
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- if (timer_stats_active)
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- time_stop = ktime_get();
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-
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- time = ktime_sub(time_stop, time_start);
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-
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- period = ktime_to_timespec64(time);
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- ms = period.tv_nsec / 1000000;
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-
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- seq_puts(m, "Timer Stats Version: v0.3\n");
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- seq_printf(m, "Sample period: %ld.%03ld s\n", (long)period.tv_sec, ms);
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- if (atomic_read(&overflow_count))
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- seq_printf(m, "Overflow: %d entries\n", atomic_read(&overflow_count));
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- seq_printf(m, "Collection: %s\n", timer_stats_active ? "active" : "inactive");
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-
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- for (i = 0; i < nr_entries; i++) {
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- entry = entries + i;
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- if (entry->flags & TIMER_DEFERRABLE) {
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- seq_printf(m, "%4luD, %5d %-16s ",
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- entry->count, entry->pid, entry->comm);
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- } else {
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- seq_printf(m, " %4lu, %5d %-16s ",
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- entry->count, entry->pid, entry->comm);
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- }
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-
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- print_name_offset(m, (unsigned long)entry->start_func);
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- seq_puts(m, " (");
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- print_name_offset(m, (unsigned long)entry->expire_func);
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- seq_puts(m, ")\n");
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-
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- events += entry->count;
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- }
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-
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- ms += period.tv_sec * 1000;
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- if (!ms)
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- ms = 1;
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-
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- if (events && period.tv_sec)
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- seq_printf(m, "%ld total events, %ld.%03ld events/sec\n",
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- events, events * 1000 / ms,
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- (events * 1000000 / ms) % 1000);
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- else
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- seq_printf(m, "%ld total events\n", events);
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-
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- mutex_unlock(&show_mutex);
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-
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- return 0;
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-}
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-
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-/*
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- * After a state change, make sure all concurrent lookup/update
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- * activities have stopped:
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- */
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-static void sync_access(void)
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-{
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- unsigned long flags;
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- int cpu;
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-
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- for_each_online_cpu(cpu) {
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- raw_spinlock_t *lock = &per_cpu(tstats_lookup_lock, cpu);
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-
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- raw_spin_lock_irqsave(lock, flags);
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- /* nothing */
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- raw_spin_unlock_irqrestore(lock, flags);
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- }
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-}
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-
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-static ssize_t tstats_write(struct file *file, const char __user *buf,
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- size_t count, loff_t *offs)
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-{
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- char ctl[2];
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-
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- if (count != 2 || *offs)
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- return -EINVAL;
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-
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- if (copy_from_user(ctl, buf, count))
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- return -EFAULT;
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-
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- mutex_lock(&show_mutex);
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- switch (ctl[0]) {
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- case '0':
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- if (timer_stats_active) {
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- timer_stats_active = 0;
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- time_stop = ktime_get();
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- sync_access();
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- }
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- break;
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- case '1':
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- if (!timer_stats_active) {
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- reset_entries();
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- time_start = ktime_get();
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- smp_mb();
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- timer_stats_active = 1;
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- }
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- break;
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- default:
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- count = -EINVAL;
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- }
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- mutex_unlock(&show_mutex);
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-
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- return count;
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-}
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-
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-static int tstats_open(struct inode *inode, struct file *filp)
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-{
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- return single_open(filp, tstats_show, NULL);
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-}
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-
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-static const struct file_operations tstats_fops = {
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- .open = tstats_open,
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- .read = seq_read,
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- .write = tstats_write,
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- .llseek = seq_lseek,
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- .release = single_release,
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-};
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-
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-void __init init_timer_stats(void)
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-{
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- int cpu;
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-
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- for_each_possible_cpu(cpu)
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- raw_spin_lock_init(&per_cpu(tstats_lookup_lock, cpu));
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-}
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-
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-static int __init init_tstats_procfs(void)
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-{
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- struct proc_dir_entry *pe;
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-
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- pe = proc_create("timer_stats", 0644, NULL, &tstats_fops);
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- if (!pe)
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- return -ENOMEM;
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- return 0;
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-}
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-__initcall(init_tstats_procfs);
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Kees Cook