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/string.h>
10 #include <linux/types.h>
11 #include "perf-sys.h"
12 #include "debug.h"
13 #include "tests/tests.h"
14 #include "cloexec.h"
15 #include "event.h"
16 #include <internal/lib.h> // page_size
17 #include "arch-tests.h"
18
rdpmc(unsigned int counter)19 static u64 rdpmc(unsigned int counter)
20 {
21 unsigned int low, high;
22
23 asm volatile("rdpmc" : "=a" (low), "=d" (high) : "c" (counter));
24
25 return low | ((u64)high) << 32;
26 }
27
rdtsc(void)28 static u64 rdtsc(void)
29 {
30 unsigned int low, high;
31
32 asm volatile("rdtsc" : "=a" (low), "=d" (high));
33
34 return low | ((u64)high) << 32;
35 }
36
mmap_read_self(void * addr)37 static u64 mmap_read_self(void *addr)
38 {
39 struct perf_event_mmap_page *pc = addr;
40 u32 seq, idx, time_mult = 0, time_shift = 0;
41 u64 count, cyc = 0, time_offset = 0, enabled, running, delta;
42
43 do {
44 seq = pc->lock;
45 barrier();
46
47 enabled = pc->time_enabled;
48 running = pc->time_running;
49
50 if (enabled != running) {
51 cyc = rdtsc();
52 time_mult = pc->time_mult;
53 time_shift = pc->time_shift;
54 time_offset = pc->time_offset;
55 }
56
57 idx = pc->index;
58 count = pc->offset;
59 if (idx)
60 count += rdpmc(idx - 1);
61
62 barrier();
63 } while (pc->lock != seq);
64
65 if (enabled != running) {
66 u64 quot, rem;
67
68 quot = (cyc >> time_shift);
69 rem = cyc & (((u64)1 << time_shift) - 1);
70 delta = time_offset + quot * time_mult +
71 ((rem * time_mult) >> time_shift);
72
73 enabled += delta;
74 if (idx)
75 running += delta;
76
77 quot = count / running;
78 rem = count % running;
79 count = quot * enabled + (rem * enabled) / running;
80 }
81
82 return count;
83 }
84
85 /*
86 * If the RDPMC instruction faults then signal this back to the test parent task:
87 */
segfault_handler(int sig __maybe_unused,siginfo_t * info __maybe_unused,void * uc __maybe_unused)88 static void segfault_handler(int sig __maybe_unused,
89 siginfo_t *info __maybe_unused,
90 void *uc __maybe_unused)
91 {
92 exit(-1);
93 }
94
__test__rdpmc(void)95 static int __test__rdpmc(void)
96 {
97 volatile int tmp = 0;
98 u64 i, loops = 1000;
99 int n;
100 int fd;
101 void *addr;
102 struct perf_event_attr attr = {
103 .type = PERF_TYPE_HARDWARE,
104 .config = PERF_COUNT_HW_INSTRUCTIONS,
105 .exclude_kernel = 1,
106 };
107 u64 delta_sum = 0;
108 struct sigaction sa;
109 char sbuf[STRERR_BUFSIZE];
110
111 sigfillset(&sa.sa_mask);
112 sa.sa_sigaction = segfault_handler;
113 sa.sa_flags = 0;
114 sigaction(SIGSEGV, &sa, NULL);
115
116 fd = sys_perf_event_open(&attr, 0, -1, -1,
117 perf_event_open_cloexec_flag());
118 if (fd < 0) {
119 pr_err("Error: sys_perf_event_open() syscall returned "
120 "with %d (%s)\n", fd,
121 str_error_r(errno, sbuf, sizeof(sbuf)));
122 return -1;
123 }
124
125 addr = mmap(NULL, page_size, PROT_READ, MAP_SHARED, fd, 0);
126 if (addr == (void *)(-1)) {
127 pr_err("Error: mmap() syscall returned with (%s)\n",
128 str_error_r(errno, sbuf, sizeof(sbuf)));
129 goto out_close;
130 }
131
132 for (n = 0; n < 6; n++) {
133 u64 stamp, now, delta;
134
135 stamp = mmap_read_self(addr);
136
137 for (i = 0; i < loops; i++)
138 tmp++;
139
140 now = mmap_read_self(addr);
141 loops *= 10;
142
143 delta = now - stamp;
144 pr_debug("%14d: %14Lu\n", n, (long long)delta);
145
146 delta_sum += delta;
147 }
148
149 munmap(addr, page_size);
150 pr_debug(" ");
151 out_close:
152 close(fd);
153
154 if (!delta_sum)
155 return -1;
156
157 return 0;
158 }
159
test__rdpmc(struct test * test __maybe_unused,int subtest __maybe_unused)160 int test__rdpmc(struct test *test __maybe_unused, int subtest __maybe_unused)
161 {
162 int status = 0;
163 int wret = 0;
164 int ret;
165 int pid;
166
167 pid = fork();
168 if (pid < 0)
169 return -1;
170
171 if (!pid) {
172 ret = __test__rdpmc();
173
174 exit(ret);
175 }
176
177 wret = waitpid(pid, &status, 0);
178 if (wret < 0 || status)
179 return -1;
180
181 return 0;
182 }
183