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 = this_cpu_ptr(&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_timer_online(unsigned int cpu)77 static int oprofile_timer_online(unsigned int cpu)
78 {
79 local_irq_disable();
80 __oprofile_hrtimer_start(NULL);
81 local_irq_enable();
82 return 0;
83 }
84
oprofile_timer_prep_down(unsigned int cpu)85 static int oprofile_timer_prep_down(unsigned int cpu)
86 {
87 __oprofile_hrtimer_stop(cpu);
88 return 0;
89 }
90
91 static enum cpuhp_state hp_online;
92
oprofile_hrtimer_setup(void)93 static int oprofile_hrtimer_setup(void)
94 {
95 int ret;
96
97 ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
98 "oprofile/timer:online",
99 oprofile_timer_online,
100 oprofile_timer_prep_down);
101 if (ret < 0)
102 return ret;
103 hp_online = ret;
104 return 0;
105 }
106
oprofile_hrtimer_shutdown(void)107 static void oprofile_hrtimer_shutdown(void)
108 {
109 cpuhp_remove_state_nocalls(hp_online);
110 }
111
oprofile_timer_init(struct oprofile_operations * ops)112 int oprofile_timer_init(struct oprofile_operations *ops)
113 {
114 ops->create_files = NULL;
115 ops->setup = oprofile_hrtimer_setup;
116 ops->shutdown = oprofile_hrtimer_shutdown;
117 ops->start = oprofile_hrtimer_start;
118 ops->stop = oprofile_hrtimer_stop;
119 ops->cpu_type = "timer";
120 printk(KERN_INFO "oprofile: using timer interrupt.\n");
121 return 0;
122 }
123