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.h"
9 #include "cloexec.h"
10
11 #if defined(__x86_64__) || defined(__i386__)
12
rdpmc(unsigned int counter)13 static u64 rdpmc(unsigned int counter)
14 {
15 unsigned int low, high;
16
17 asm volatile("rdpmc" : "=a" (low), "=d" (high) : "c" (counter));
18
19 return low | ((u64)high) << 32;
20 }
21
rdtsc(void)22 static u64 rdtsc(void)
23 {
24 unsigned int low, high;
25
26 asm volatile("rdtsc" : "=a" (low), "=d" (high));
27
28 return low | ((u64)high) << 32;
29 }
30
mmap_read_self(void * addr)31 static u64 mmap_read_self(void *addr)
32 {
33 struct perf_event_mmap_page *pc = addr;
34 u32 seq, idx, time_mult = 0, time_shift = 0;
35 u64 count, cyc = 0, time_offset = 0, enabled, running, delta;
36
37 do {
38 seq = pc->lock;
39 barrier();
40
41 enabled = pc->time_enabled;
42 running = pc->time_running;
43
44 if (enabled != running) {
45 cyc = rdtsc();
46 time_mult = pc->time_mult;
47 time_shift = pc->time_shift;
48 time_offset = pc->time_offset;
49 }
50
51 idx = pc->index;
52 count = pc->offset;
53 if (idx)
54 count += rdpmc(idx - 1);
55
56 barrier();
57 } while (pc->lock != seq);
58
59 if (enabled != running) {
60 u64 quot, rem;
61
62 quot = (cyc >> time_shift);
63 rem = cyc & ((1 << time_shift) - 1);
64 delta = time_offset + quot * time_mult +
65 ((rem * time_mult) >> time_shift);
66
67 enabled += delta;
68 if (idx)
69 running += delta;
70
71 quot = count / running;
72 rem = count % running;
73 count = quot * enabled + (rem * enabled) / running;
74 }
75
76 return count;
77 }
78
79 /*
80 * If the RDPMC instruction faults then signal this back to the test parent task:
81 */
segfault_handler(int sig __maybe_unused,siginfo_t * info __maybe_unused,void * uc __maybe_unused)82 static void segfault_handler(int sig __maybe_unused,
83 siginfo_t *info __maybe_unused,
84 void *uc __maybe_unused)
85 {
86 exit(-1);
87 }
88
__test__rdpmc(void)89 static int __test__rdpmc(void)
90 {
91 volatile int tmp = 0;
92 u64 i, loops = 1000;
93 int n;
94 int fd;
95 void *addr;
96 struct perf_event_attr attr = {
97 .type = PERF_TYPE_HARDWARE,
98 .config = PERF_COUNT_HW_INSTRUCTIONS,
99 .exclude_kernel = 1,
100 };
101 u64 delta_sum = 0;
102 struct sigaction sa;
103 char sbuf[STRERR_BUFSIZE];
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,
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(" ");
144 out_close:
145 close(fd);
146
147 if (!delta_sum)
148 return -1;
149
150 return 0;
151 }
152
test__rdpmc(void)153 int test__rdpmc(void)
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
177 #endif
178