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
23 static DEFINE_PER_CPU(struct hrtimer, oprofile_hrtimer);
24 static int ctr_running;
25
oprofile_hrtimer_notify(struct hrtimer * hrtimer)26 static 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
__oprofile_hrtimer_start(void * unused)33 static 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
oprofile_hrtimer_start(void)47 static 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
__oprofile_hrtimer_stop(int cpu)56 static 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
oprofile_hrtimer_stop(void)66 static 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
oprofile_cpu_notify(struct notifier_block * self,unsigned long action,void * hcpu)77 static 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
96 static struct notifier_block __refdata oprofile_cpu_notifier = {
97 .notifier_call = oprofile_cpu_notify,
98 };
99
oprofile_hrtimer_setup(void)100 static int oprofile_hrtimer_setup(void)
101 {
102 return register_hotcpu_notifier(&oprofile_cpu_notifier);
103 }
104
oprofile_hrtimer_shutdown(void)105 static void oprofile_hrtimer_shutdown(void)
106 {
107 unregister_hotcpu_notifier(&oprofile_cpu_notifier);
108 }
109
oprofile_timer_init(struct oprofile_operations * ops)110 int 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