]>
Commit | Line | Data |
---|---|---|
b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
dcfce4a0 RR |
2 | /** |
3 | * @file nmi_timer_int.c | |
4 | * | |
5 | * @remark Copyright 2011 Advanced Micro Devices, Inc. | |
6 | * | |
7 | * @author Robert Richter <robert.richter@amd.com> | |
8 | */ | |
9 | ||
10 | #include <linux/init.h> | |
11 | #include <linux/smp.h> | |
12 | #include <linux/errno.h> | |
13 | #include <linux/oprofile.h> | |
14 | #include <linux/perf_event.h> | |
15 | ||
16 | #ifdef CONFIG_OPROFILE_NMI_TIMER | |
17 | ||
18 | static DEFINE_PER_CPU(struct perf_event *, nmi_timer_events); | |
19 | static int ctr_running; | |
20 | ||
21 | static struct perf_event_attr nmi_timer_attr = { | |
22 | .type = PERF_TYPE_HARDWARE, | |
23 | .config = PERF_COUNT_HW_CPU_CYCLES, | |
24 | .size = sizeof(struct perf_event_attr), | |
25 | .pinned = 1, | |
26 | .disabled = 1, | |
27 | }; | |
28 | ||
29 | static void nmi_timer_callback(struct perf_event *event, | |
30 | struct perf_sample_data *data, | |
31 | struct pt_regs *regs) | |
32 | { | |
33 | event->hw.interrupts = 0; /* don't throttle interrupts */ | |
34 | oprofile_add_sample(regs, 0); | |
35 | } | |
36 | ||
37 | static int nmi_timer_start_cpu(int cpu) | |
38 | { | |
39 | struct perf_event *event = per_cpu(nmi_timer_events, cpu); | |
40 | ||
41 | if (!event) { | |
42 | event = perf_event_create_kernel_counter(&nmi_timer_attr, cpu, NULL, | |
43 | nmi_timer_callback, NULL); | |
44 | if (IS_ERR(event)) | |
45 | return PTR_ERR(event); | |
46 | per_cpu(nmi_timer_events, cpu) = event; | |
47 | } | |
48 | ||
49 | if (event && ctr_running) | |
50 | perf_event_enable(event); | |
51 | ||
52 | return 0; | |
53 | } | |
54 | ||
55 | static void nmi_timer_stop_cpu(int cpu) | |
56 | { | |
57 | struct perf_event *event = per_cpu(nmi_timer_events, cpu); | |
58 | ||
59 | if (event && ctr_running) | |
60 | perf_event_disable(event); | |
61 | } | |
62 | ||
14660b7e | 63 | static int nmi_timer_cpu_online(unsigned int cpu) |
dcfce4a0 | 64 | { |
14660b7e SAS |
65 | nmi_timer_start_cpu(cpu); |
66 | return 0; | |
67 | } | |
68 | static int nmi_timer_cpu_predown(unsigned int cpu) | |
69 | { | |
70 | nmi_timer_stop_cpu(cpu); | |
71 | return 0; | |
dcfce4a0 | 72 | } |
dcfce4a0 RR |
73 | |
74 | static int nmi_timer_start(void) | |
75 | { | |
76 | int cpu; | |
77 | ||
78 | get_online_cpus(); | |
79 | ctr_running = 1; | |
80 | for_each_online_cpu(cpu) | |
81 | nmi_timer_start_cpu(cpu); | |
82 | put_online_cpus(); | |
83 | ||
84 | return 0; | |
85 | } | |
86 | ||
87 | static void nmi_timer_stop(void) | |
88 | { | |
89 | int cpu; | |
90 | ||
91 | get_online_cpus(); | |
92 | for_each_online_cpu(cpu) | |
93 | nmi_timer_stop_cpu(cpu); | |
94 | ctr_running = 0; | |
95 | put_online_cpus(); | |
96 | } | |
97 | ||
14660b7e SAS |
98 | static enum cpuhp_state hp_online; |
99 | ||
dcfce4a0 RR |
100 | static void nmi_timer_shutdown(void) |
101 | { | |
102 | struct perf_event *event; | |
103 | int cpu; | |
104 | ||
14660b7e | 105 | cpuhp_remove_state(hp_online); |
dcfce4a0 RR |
106 | for_each_possible_cpu(cpu) { |
107 | event = per_cpu(nmi_timer_events, cpu); | |
108 | if (!event) | |
109 | continue; | |
110 | perf_event_disable(event); | |
111 | per_cpu(nmi_timer_events, cpu) = NULL; | |
112 | perf_event_release_kernel(event); | |
113 | } | |
dcfce4a0 RR |
114 | } |
115 | ||
116 | static int nmi_timer_setup(void) | |
117 | { | |
14660b7e | 118 | int err; |
dcfce4a0 RR |
119 | u64 period; |
120 | ||
121 | /* clock cycles per tick: */ | |
122 | period = (u64)cpu_khz * 1000; | |
123 | do_div(period, HZ); | |
124 | nmi_timer_attr.sample_period = period; | |
125 | ||
14660b7e SAS |
126 | err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "oprofile/nmi:online", |
127 | nmi_timer_cpu_online, nmi_timer_cpu_predown); | |
128 | if (err < 0) { | |
129 | nmi_timer_shutdown(); | |
130 | return err; | |
dcfce4a0 | 131 | } |
14660b7e SAS |
132 | hp_online = err; |
133 | return 0; | |
dcfce4a0 RR |
134 | } |
135 | ||
136 | int __init op_nmi_timer_init(struct oprofile_operations *ops) | |
137 | { | |
138 | int err = 0; | |
139 | ||
140 | err = nmi_timer_setup(); | |
141 | if (err) | |
142 | return err; | |
143 | nmi_timer_shutdown(); /* only check, don't alloc */ | |
144 | ||
145 | ops->create_files = NULL; | |
146 | ops->setup = nmi_timer_setup; | |
147 | ops->shutdown = nmi_timer_shutdown; | |
148 | ops->start = nmi_timer_start; | |
149 | ops->stop = nmi_timer_stop; | |
150 | ops->cpu_type = "timer"; | |
151 | ||
152 | printk(KERN_INFO "oprofile: using NMI timer interrupt.\n"); | |
153 | ||
154 | return 0; | |
155 | } | |
156 | ||
157 | #endif |