1 // SPDX-License-Identifier: GPL-2.0
2 #include <errno.h>
3 #include <unistd.h>
4 #include <stdlib.h>
5 #include <signal.h>
6 #include <sys/mman.h>
7 #include <sys/types.h>
8 #include <sys/wait.h>
9 #include <linux/types.h>
10 #include "perf.h"
11 #include "debug.h"
12 #include "tests/tests.h"
13 #include "cloexec.h"
14 #include "util.h"
15 #include "arch-tests.h"
16
rdpmc(unsigned int counter)17 static u64 rdpmc(unsigned int counter)
18 {
19 unsigned int low, high;
20
21 asm volatile("rdpmc" : "=a" (low), "=d" (high) : "c" (counter));
22
23 return low | ((u64)high) << 32;
24 }
25
rdtsc(void)26 static u64 rdtsc(void)
27 {
28 unsigned int low, high;
29
30 asm volatile("rdtsc" : "=a" (low), "=d" (high));
31
32 return low | ((u64)high) << 32;
33 }
34
mmap_read_self(void * addr)35 static u64 mmap_read_self(void *addr)
36 {
37 struct perf_event_mmap_page *pc = addr;
38 u32 seq, idx, time_mult = 0, time_shift = 0;
39 u64 count, cyc = 0, time_offset = 0, enabled, running, delta;
40
41 do {
42 seq = pc->lock;
43 barrier();
44
45 enabled = pc->time_enabled;
46 running = pc->time_running;
47
48 if (enabled != running) {
49 cyc = rdtsc();
50 time_mult = pc->time_mult;
51 time_shift = pc->time_shift;
52 time_offset = pc->time_offset;
53 }
54
55 idx = pc->index;
56 count = pc->offset;
57 if (idx)
58 count += rdpmc(idx - 1);
59
60 barrier();
61 } while (pc->lock != seq);
62
63 if (enabled != running) {
64 u64 quot, rem;
65
66 quot = (cyc >> time_shift);
67 rem = cyc & (((u64)1 << time_shift) - 1);
68 delta = time_offset + quot * time_mult +
69 ((rem * time_mult) >> time_shift);
70
71 enabled += delta;
72 if (idx)
73 running += delta;
74
75 quot = count / running;
76 rem = count % running;
77 count = quot * enabled + (rem * enabled) / running;
78 }
79
80 return count;
81 }
82
83 /*
84 * If the RDPMC instruction faults then signal this back to the test parent task:
85 */
segfault_handler(int sig __maybe_unused,siginfo_t * info __maybe_unused,void * uc __maybe_unused)86 static void segfault_handler(int sig __maybe_unused,
87 siginfo_t *info __maybe_unused,
88 void *uc __maybe_unused)
89 {
90 exit(-1);
91 }
92
__test__rdpmc(void)93 static int __test__rdpmc(void)
94 {
95 volatile int tmp = 0;
96 u64 i, loops = 1000;
97 int n;
98 int fd;
99 void *addr;
100 struct perf_event_attr attr = {
101 .type = PERF_TYPE_HARDWARE,
102 .config = PERF_COUNT_HW_INSTRUCTIONS,
103 .exclude_kernel = 1,
104 };
105 u64 delta_sum = 0;
106 struct sigaction sa;
107 char sbuf[STRERR_BUFSIZE];
108
109 sigfillset(&sa.sa_mask);
110 sa.sa_sigaction = segfault_handler;
111 sa.sa_flags = 0;
112 sigaction(SIGSEGV, &sa, NULL);
113
114 fd = sys_perf_event_open(&attr, 0, -1, -1,
115 perf_event_open_cloexec_flag());
116 if (fd < 0) {
117 pr_err("Error: sys_perf_event_open() syscall returned "
118 "with %d (%s)\n", fd,
119 str_error_r(errno, sbuf, sizeof(sbuf)));
120 return -1;
121 }
122
123 addr = mmap(NULL, page_size, PROT_READ, MAP_SHARED, fd, 0);
124 if (addr == (void *)(-1)) {
125 pr_err("Error: mmap() syscall returned with (%s)\n",
126 str_error_r(errno, sbuf, sizeof(sbuf)));
127 goto out_close;
128 }
129
130 for (n = 0; n < 6; n++) {
131 u64 stamp, now, delta;
132
133 stamp = mmap_read_self(addr);
134
135 for (i = 0; i < loops; i++)
136 tmp++;
137
138 now = mmap_read_self(addr);
139 loops *= 10;
140
141 delta = now - stamp;
142 pr_debug("%14d: %14Lu\n", n, (long long)delta);
143
144 delta_sum += delta;
145 }
146
147 munmap(addr, page_size);
148 pr_debug(" ");
149 out_close:
150 close(fd);
151
152 if (!delta_sum)
153 return -1;
154
155 return 0;
156 }
157
test__rdpmc(struct test * test __maybe_unused,int subtest __maybe_unused)158 int test__rdpmc(struct test *test __maybe_unused, int subtest __maybe_unused)
159 {
160 int status = 0;
161 int wret = 0;
162 int ret;
163 int pid;
164
165 pid = fork();
166 if (pid < 0)
167 return -1;
168
169 if (!pid) {
170 ret = __test__rdpmc();
171
172 exit(ret);
173 }
174
175 wret = waitpid(pid, &status, 0);
176 if (wret < 0 || status)
177 return -1;
178
179 return 0;
180 }
181