Root/drivers/oprofile/timer_int.c

1/**
2 * @file timer_int.c
3 *
4 * @remark Copyright 2002 OProfile authors
5 * @remark Read the file COPYING
6 *
7 * @author John Levon <levon@movementarian.org>
8 */
9
10#include <linux/kernel.h>
11#include <linux/notifier.h>
12#include <linux/smp.h>
13#include <linux/oprofile.h>
14#include <linux/profile.h>
15#include <linux/init.h>
16#include <linux/cpu.h>
17#include <linux/hrtimer.h>
18#include <asm/irq_regs.h>
19#include <asm/ptrace.h>
20
21#include "oprof.h"
22
23static DEFINE_PER_CPU(struct hrtimer, oprofile_hrtimer);
24static int ctr_running;
25
26static enum hrtimer_restart oprofile_hrtimer_notify(struct hrtimer *hrtimer)
27{
28    oprofile_add_sample(get_irq_regs(), 0);
29    hrtimer_forward_now(hrtimer, ns_to_ktime(TICK_NSEC));
30    return HRTIMER_RESTART;
31}
32
33static void __oprofile_hrtimer_start(void *unused)
34{
35    struct hrtimer *hrtimer = &__get_cpu_var(oprofile_hrtimer);
36
37    if (!ctr_running)
38        return;
39
40    hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
41    hrtimer->function = oprofile_hrtimer_notify;
42
43    hrtimer_start(hrtimer, ns_to_ktime(TICK_NSEC),
44              HRTIMER_MODE_REL_PINNED);
45}
46
47static int oprofile_hrtimer_start(void)
48{
49    get_online_cpus();
50    ctr_running = 1;
51    on_each_cpu(__oprofile_hrtimer_start, NULL, 1);
52    put_online_cpus();
53    return 0;
54}
55
56static void __oprofile_hrtimer_stop(int cpu)
57{
58    struct hrtimer *hrtimer = &per_cpu(oprofile_hrtimer, cpu);
59
60    if (!ctr_running)
61        return;
62
63    hrtimer_cancel(hrtimer);
64}
65
66static void oprofile_hrtimer_stop(void)
67{
68    int cpu;
69
70    get_online_cpus();
71    for_each_online_cpu(cpu)
72        __oprofile_hrtimer_stop(cpu);
73    ctr_running = 0;
74    put_online_cpus();
75}
76
77static int __cpuinit oprofile_cpu_notify(struct notifier_block *self,
78                     unsigned long action, void *hcpu)
79{
80    long cpu = (long) hcpu;
81
82    switch (action) {
83    case CPU_ONLINE:
84    case CPU_ONLINE_FROZEN:
85        smp_call_function_single(cpu, __oprofile_hrtimer_start,
86                     NULL, 1);
87        break;
88    case CPU_DEAD:
89    case CPU_DEAD_FROZEN:
90        __oprofile_hrtimer_stop(cpu);
91        break;
92    }
93    return NOTIFY_OK;
94}
95
96static struct notifier_block __refdata oprofile_cpu_notifier = {
97    .notifier_call = oprofile_cpu_notify,
98};
99
100static int oprofile_hrtimer_setup(void)
101{
102    return register_hotcpu_notifier(&oprofile_cpu_notifier);
103}
104
105static void oprofile_hrtimer_shutdown(void)
106{
107    unregister_hotcpu_notifier(&oprofile_cpu_notifier);
108}
109
110int oprofile_timer_init(struct oprofile_operations *ops)
111{
112    ops->create_files = NULL;
113    ops->setup = oprofile_hrtimer_setup;
114    ops->shutdown = oprofile_hrtimer_shutdown;
115    ops->start = oprofile_hrtimer_start;
116    ops->stop = oprofile_hrtimer_stop;
117    ops->cpu_type = "timer";
118    printk(KERN_INFO "oprofile: using timer interrupt.\n");
119    return 0;
120}
121

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