1#include <unistd.h>
2#include <stdlib.h>
3#include <signal.h>
4#include <sys/mman.h>
5#include <linux/types.h>
6#include "perf.h"
7#include "debug.h"
8#include "tests/tests.h"
9#include "cloexec.h"
10#include "arch-tests.h"
11
12static u64 rdpmc(unsigned int counter)
13{
14 unsigned int low, high;
15
16 asm volatile("rdpmc" : "=a" (low), "=d" (high) : "c" (counter));
17
18 return low | ((u64)high) << 32;
19}
20
21static u64 rdtsc(void)
22{
23 unsigned int low, high;
24
25 asm volatile("rdtsc" : "=a" (low), "=d" (high));
26
27 return low | ((u64)high) << 32;
28}
29
30static u64 mmap_read_self(void *addr)
31{
32 struct perf_event_mmap_page *pc = addr;
33 u32 seq, idx, time_mult = 0, time_shift = 0;
34 u64 count, cyc = 0, time_offset = 0, enabled, running, delta;
35
36 do {
37 seq = pc->lock;
38 barrier();
39
40 enabled = pc->time_enabled;
41 running = pc->time_running;
42
43 if (enabled != running) {
44 cyc = rdtsc();
45 time_mult = pc->time_mult;
46 time_shift = pc->time_shift;
47 time_offset = pc->time_offset;
48 }
49
50 idx = pc->index;
51 count = pc->offset;
52 if (idx)
53 count += rdpmc(idx - 1);
54
55 barrier();
56 } while (pc->lock != seq);
57
58 if (enabled != running) {
59 u64 quot, rem;
60
61 quot = (cyc >> time_shift);
62 rem = cyc & (((u64)1 << time_shift) - 1);
63 delta = time_offset + quot * time_mult +
64 ((rem * time_mult) >> time_shift);
65
66 enabled += delta;
67 if (idx)
68 running += delta;
69
70 quot = count / running;
71 rem = count % running;
72 count = quot * enabled + (rem * enabled) / running;
73 }
74
75 return count;
76}
77
78
79
80
81static void segfault_handler(int sig __maybe_unused,
82 siginfo_t *info __maybe_unused,
83 void *uc __maybe_unused)
84{
85 exit(-1);
86}
87
88static int __test__rdpmc(void)
89{
90 volatile int tmp = 0;
91 u64 i, loops = 1000;
92 int n;
93 int fd;
94 void *addr;
95 struct perf_event_attr attr = {
96 .type = PERF_TYPE_HARDWARE,
97 .config = PERF_COUNT_HW_INSTRUCTIONS,
98 .exclude_kernel = 1,
99 };
100 u64 delta_sum = 0;
101 struct sigaction sa;
102 char sbuf[STRERR_BUFSIZE];
103
104 sigfillset(&sa.sa_mask);
105 sa.sa_sigaction = segfault_handler;
106 sa.sa_flags = 0;
107 sigaction(SIGSEGV, &sa, NULL);
108
109 fd = sys_perf_event_open(&attr, 0, -1, -1,
110 perf_event_open_cloexec_flag());
111 if (fd < 0) {
112 pr_err("Error: sys_perf_event_open() syscall returned "
113 "with %d (%s)\n", fd,
114 strerror_r(errno, sbuf, sizeof(sbuf)));
115 return -1;
116 }
117
118 addr = mmap(NULL, page_size, PROT_READ, MAP_SHARED, fd, 0);
119 if (addr == (void *)(-1)) {
120 pr_err("Error: mmap() syscall returned with (%s)\n",
121 strerror_r(errno, sbuf, sizeof(sbuf)));
122 goto out_close;
123 }
124
125 for (n = 0; n < 6; n++) {
126 u64 stamp, now, delta;
127
128 stamp = mmap_read_self(addr);
129
130 for (i = 0; i < loops; i++)
131 tmp++;
132
133 now = mmap_read_self(addr);
134 loops *= 10;
135
136 delta = now - stamp;
137 pr_debug("%14d: %14Lu\n", n, (long long)delta);
138
139 delta_sum += delta;
140 }
141
142 munmap(addr, page_size);
143 pr_debug(" ");
144out_close:
145 close(fd);
146
147 if (!delta_sum)
148 return -1;
149
150 return 0;
151}
152
153int test__rdpmc(int subtest __maybe_unused)
154{
155 int status = 0;
156 int wret = 0;
157 int ret;
158 int pid;
159
160 pid = fork();
161 if (pid < 0)
162 return -1;
163
164 if (!pid) {
165 ret = __test__rdpmc();
166
167 exit(ret);
168 }
169
170 wret = waitpid(pid, &status, 0);
171 if (wret < 0 || status)
172 return -1;
173
174 return 0;
175}
176
