1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun /**
3*4882a593Smuzhiyun * @file nmi_timer_int.c
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * @remark Copyright 2011 Advanced Micro Devices, Inc.
6*4882a593Smuzhiyun *
7*4882a593Smuzhiyun * @author Robert Richter <robert.richter@amd.com>
8*4882a593Smuzhiyun */
9*4882a593Smuzhiyun
10*4882a593Smuzhiyun #include <linux/init.h>
11*4882a593Smuzhiyun #include <linux/smp.h>
12*4882a593Smuzhiyun #include <linux/errno.h>
13*4882a593Smuzhiyun #include <linux/oprofile.h>
14*4882a593Smuzhiyun #include <linux/perf_event.h>
15*4882a593Smuzhiyun
16*4882a593Smuzhiyun #ifdef CONFIG_OPROFILE_NMI_TIMER
17*4882a593Smuzhiyun
18*4882a593Smuzhiyun static DEFINE_PER_CPU(struct perf_event *, nmi_timer_events);
19*4882a593Smuzhiyun static int ctr_running;
20*4882a593Smuzhiyun
21*4882a593Smuzhiyun static struct perf_event_attr nmi_timer_attr = {
22*4882a593Smuzhiyun .type = PERF_TYPE_HARDWARE,
23*4882a593Smuzhiyun .config = PERF_COUNT_HW_CPU_CYCLES,
24*4882a593Smuzhiyun .size = sizeof(struct perf_event_attr),
25*4882a593Smuzhiyun .pinned = 1,
26*4882a593Smuzhiyun .disabled = 1,
27*4882a593Smuzhiyun };
28*4882a593Smuzhiyun
nmi_timer_callback(struct perf_event * event,struct perf_sample_data * data,struct pt_regs * regs)29*4882a593Smuzhiyun static void nmi_timer_callback(struct perf_event *event,
30*4882a593Smuzhiyun struct perf_sample_data *data,
31*4882a593Smuzhiyun struct pt_regs *regs)
32*4882a593Smuzhiyun {
33*4882a593Smuzhiyun event->hw.interrupts = 0; /* don't throttle interrupts */
34*4882a593Smuzhiyun oprofile_add_sample(regs, 0);
35*4882a593Smuzhiyun }
36*4882a593Smuzhiyun
nmi_timer_start_cpu(int cpu)37*4882a593Smuzhiyun static int nmi_timer_start_cpu(int cpu)
38*4882a593Smuzhiyun {
39*4882a593Smuzhiyun struct perf_event *event = per_cpu(nmi_timer_events, cpu);
40*4882a593Smuzhiyun
41*4882a593Smuzhiyun if (!event) {
42*4882a593Smuzhiyun event = perf_event_create_kernel_counter(&nmi_timer_attr, cpu, NULL,
43*4882a593Smuzhiyun nmi_timer_callback, NULL);
44*4882a593Smuzhiyun if (IS_ERR(event))
45*4882a593Smuzhiyun return PTR_ERR(event);
46*4882a593Smuzhiyun per_cpu(nmi_timer_events, cpu) = event;
47*4882a593Smuzhiyun }
48*4882a593Smuzhiyun
49*4882a593Smuzhiyun if (event && ctr_running)
50*4882a593Smuzhiyun perf_event_enable(event);
51*4882a593Smuzhiyun
52*4882a593Smuzhiyun return 0;
53*4882a593Smuzhiyun }
54*4882a593Smuzhiyun
nmi_timer_stop_cpu(int cpu)55*4882a593Smuzhiyun static void nmi_timer_stop_cpu(int cpu)
56*4882a593Smuzhiyun {
57*4882a593Smuzhiyun struct perf_event *event = per_cpu(nmi_timer_events, cpu);
58*4882a593Smuzhiyun
59*4882a593Smuzhiyun if (event && ctr_running)
60*4882a593Smuzhiyun perf_event_disable(event);
61*4882a593Smuzhiyun }
62*4882a593Smuzhiyun
nmi_timer_cpu_online(unsigned int cpu)63*4882a593Smuzhiyun static int nmi_timer_cpu_online(unsigned int cpu)
64*4882a593Smuzhiyun {
65*4882a593Smuzhiyun nmi_timer_start_cpu(cpu);
66*4882a593Smuzhiyun return 0;
67*4882a593Smuzhiyun }
nmi_timer_cpu_predown(unsigned int cpu)68*4882a593Smuzhiyun static int nmi_timer_cpu_predown(unsigned int cpu)
69*4882a593Smuzhiyun {
70*4882a593Smuzhiyun nmi_timer_stop_cpu(cpu);
71*4882a593Smuzhiyun return 0;
72*4882a593Smuzhiyun }
73*4882a593Smuzhiyun
nmi_timer_start(void)74*4882a593Smuzhiyun static int nmi_timer_start(void)
75*4882a593Smuzhiyun {
76*4882a593Smuzhiyun int cpu;
77*4882a593Smuzhiyun
78*4882a593Smuzhiyun get_online_cpus();
79*4882a593Smuzhiyun ctr_running = 1;
80*4882a593Smuzhiyun for_each_online_cpu(cpu)
81*4882a593Smuzhiyun nmi_timer_start_cpu(cpu);
82*4882a593Smuzhiyun put_online_cpus();
83*4882a593Smuzhiyun
84*4882a593Smuzhiyun return 0;
85*4882a593Smuzhiyun }
86*4882a593Smuzhiyun
nmi_timer_stop(void)87*4882a593Smuzhiyun static void nmi_timer_stop(void)
88*4882a593Smuzhiyun {
89*4882a593Smuzhiyun int cpu;
90*4882a593Smuzhiyun
91*4882a593Smuzhiyun get_online_cpus();
92*4882a593Smuzhiyun for_each_online_cpu(cpu)
93*4882a593Smuzhiyun nmi_timer_stop_cpu(cpu);
94*4882a593Smuzhiyun ctr_running = 0;
95*4882a593Smuzhiyun put_online_cpus();
96*4882a593Smuzhiyun }
97*4882a593Smuzhiyun
98*4882a593Smuzhiyun static enum cpuhp_state hp_online;
99*4882a593Smuzhiyun
nmi_timer_shutdown(void)100*4882a593Smuzhiyun static void nmi_timer_shutdown(void)
101*4882a593Smuzhiyun {
102*4882a593Smuzhiyun struct perf_event *event;
103*4882a593Smuzhiyun int cpu;
104*4882a593Smuzhiyun
105*4882a593Smuzhiyun cpuhp_remove_state(hp_online);
106*4882a593Smuzhiyun for_each_possible_cpu(cpu) {
107*4882a593Smuzhiyun event = per_cpu(nmi_timer_events, cpu);
108*4882a593Smuzhiyun if (!event)
109*4882a593Smuzhiyun continue;
110*4882a593Smuzhiyun perf_event_disable(event);
111*4882a593Smuzhiyun per_cpu(nmi_timer_events, cpu) = NULL;
112*4882a593Smuzhiyun perf_event_release_kernel(event);
113*4882a593Smuzhiyun }
114*4882a593Smuzhiyun }
115*4882a593Smuzhiyun
nmi_timer_setup(void)116*4882a593Smuzhiyun static int nmi_timer_setup(void)
117*4882a593Smuzhiyun {
118*4882a593Smuzhiyun int err;
119*4882a593Smuzhiyun u64 period;
120*4882a593Smuzhiyun
121*4882a593Smuzhiyun /* clock cycles per tick: */
122*4882a593Smuzhiyun period = (u64)cpu_khz * 1000;
123*4882a593Smuzhiyun do_div(period, HZ);
124*4882a593Smuzhiyun nmi_timer_attr.sample_period = period;
125*4882a593Smuzhiyun
126*4882a593Smuzhiyun err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "oprofile/nmi:online",
127*4882a593Smuzhiyun nmi_timer_cpu_online, nmi_timer_cpu_predown);
128*4882a593Smuzhiyun if (err < 0) {
129*4882a593Smuzhiyun nmi_timer_shutdown();
130*4882a593Smuzhiyun return err;
131*4882a593Smuzhiyun }
132*4882a593Smuzhiyun hp_online = err;
133*4882a593Smuzhiyun return 0;
134*4882a593Smuzhiyun }
135*4882a593Smuzhiyun
op_nmi_timer_init(struct oprofile_operations * ops)136*4882a593Smuzhiyun int __init op_nmi_timer_init(struct oprofile_operations *ops)
137*4882a593Smuzhiyun {
138*4882a593Smuzhiyun int err = 0;
139*4882a593Smuzhiyun
140*4882a593Smuzhiyun err = nmi_timer_setup();
141*4882a593Smuzhiyun if (err)
142*4882a593Smuzhiyun return err;
143*4882a593Smuzhiyun nmi_timer_shutdown(); /* only check, don't alloc */
144*4882a593Smuzhiyun
145*4882a593Smuzhiyun ops->create_files = NULL;
146*4882a593Smuzhiyun ops->setup = nmi_timer_setup;
147*4882a593Smuzhiyun ops->shutdown = nmi_timer_shutdown;
148*4882a593Smuzhiyun ops->start = nmi_timer_start;
149*4882a593Smuzhiyun ops->stop = nmi_timer_stop;
150*4882a593Smuzhiyun ops->cpu_type = "timer";
151*4882a593Smuzhiyun
152*4882a593Smuzhiyun printk(KERN_INFO "oprofile: using NMI timer interrupt.\n");
153*4882a593Smuzhiyun
154*4882a593Smuzhiyun return 0;
155*4882a593Smuzhiyun }
156*4882a593Smuzhiyun
157*4882a593Smuzhiyun #endif
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