1#include <unistd.h>
2#include <stdlib.h>
3#include <signal.h>
4#include <sys/mman.h>
5#include "types.h"
6#include "perf.h"
7#include "debug.h"
8#include "tests.h"
9
10#if defined(__x86_64__) || defined(__i386__)
11
12#define barrier() asm volatile("" ::: "memory")
13
14static u64 rdpmc(unsigned int counter)
15{
16 unsigned int low, high;
17
18 asm volatile("rdpmc" : "=a" (low), "=d" (high) : "c" (counter));
19
20 return low | ((u64)high) << 32;
21}
22
23static u64 rdtsc(void)
24{
25 unsigned int low, high;
26
27 asm volatile("rdtsc" : "=a" (low), "=d" (high));
28
29 return low | ((u64)high) << 32;
30}
31
32static u64 mmap_read_self(void *addr)
33{
34 struct perf_event_mmap_page *pc = addr;
35 u32 seq, idx, time_mult = 0, time_shift = 0;
36 u64 count, cyc = 0, time_offset = 0, enabled, running, delta;
37
38 do {
39 seq = pc->lock;
40 barrier();
41
42 enabled = pc->time_enabled;
43 running = pc->time_running;
44
45 if (enabled != running) {
46 cyc = rdtsc();
47 time_mult = pc->time_mult;
48 time_shift = pc->time_shift;
49 time_offset = pc->time_offset;
50 }
51
52 idx = pc->index;
53 count = pc->offset;
54 if (idx)
55 count += rdpmc(idx - 1);
56
57 barrier();
58 } while (pc->lock != seq);
59
60 if (enabled != running) {
61 u64 quot, rem;
62
63 quot = (cyc >> time_shift);
64 rem = cyc & ((1 << time_shift) - 1);
65 delta = time_offset + quot * time_mult +
66 ((rem * time_mult) >> time_shift);
67
68 enabled += delta;
69 if (idx)
70 running += delta;
71
72 quot = count / running;
73 rem = count % running;
74 count = quot * enabled + (rem * enabled) / running;
75 }
76
77 return count;
78}
79
80
81
82
83static void segfault_handler(int sig __maybe_unused,
84 siginfo_t *info __maybe_unused,
85 void *uc __maybe_unused)
86{
87 exit(-1);
88}
89
90static int __test__rdpmc(void)
91{
92 volatile int tmp = 0;
93 u64 i, loops = 1000;
94 int n;
95 int fd;
96 void *addr;
97 struct perf_event_attr attr = {
98 .type = PERF_TYPE_HARDWARE,
99 .config = PERF_COUNT_HW_INSTRUCTIONS,
100 .exclude_kernel = 1,
101 };
102 u64 delta_sum = 0;
103 struct sigaction sa;
104
105 sigfillset(&sa.sa_mask);
106 sa.sa_sigaction = segfault_handler;
107 sigaction(SIGSEGV, &sa, NULL);
108
109 fd = sys_perf_event_open(&attr, 0, -1, -1, 0);
110 if (fd < 0) {
111 pr_err("Error: sys_perf_event_open() syscall returned "
112 "with %d (%s)\n", fd, strerror(errno));
113 return -1;
114 }
115
116 addr = mmap(NULL, page_size, PROT_READ, MAP_SHARED, fd, 0);
117 if (addr == (void *)(-1)) {
118 pr_err("Error: mmap() syscall returned with (%s)\n",
119 strerror(errno));
120 goto out_close;
121 }
122
123 for (n = 0; n < 6; n++) {
124 u64 stamp, now, delta;
125
126 stamp = mmap_read_self(addr);
127
128 for (i = 0; i < loops; i++)
129 tmp++;
130
131 now = mmap_read_self(addr);
132 loops *= 10;
133
134 delta = now - stamp;
135 pr_debug("%14d: %14Lu\n", n, (long long)delta);
136
137 delta_sum += delta;
138 }
139
140 munmap(addr, page_size);
141 pr_debug(" ");
142out_close:
143 close(fd);
144
145 if (!delta_sum)
146 return -1;
147
148 return 0;
149}
150
151int test__rdpmc(void)
152{
153 int status = 0;
154 int wret = 0;
155 int ret;
156 int pid;
157
158 pid = fork();
159 if (pid < 0)
160 return -1;
161
162 if (!pid) {
163 ret = __test__rdpmc();
164
165 exit(ret);
166 }
167
168 wret = waitpid(pid, &status, 0);
169 if (wret < 0 || status)
170 return -1;
171
172 return 0;
173}
174
175#endif
176
