5 #include <linux/types.h>
10 #if defined(__x86_64__) || defined(__i386__)
12 static u64 rdpmc(unsigned int counter)
14 unsigned int low, high;
16 asm volatile("rdpmc" : "=a" (low), "=d" (high) : "c" (counter));
18 return low | ((u64)high) << 32;
21 static u64 rdtsc(void)
23 unsigned int low, high;
25 asm volatile("rdtsc" : "=a" (low), "=d" (high));
27 return low | ((u64)high) << 32;
30 static u64 mmap_read_self(void *addr)
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;
40 enabled = pc->time_enabled;
41 running = pc->time_running;
43 if (enabled != running) {
45 time_mult = pc->time_mult;
46 time_shift = pc->time_shift;
47 time_offset = pc->time_offset;
53 count += rdpmc(idx - 1);
56 } while (pc->lock != seq);
58 if (enabled != running) {
61 quot = (cyc >> time_shift);
62 rem = cyc & ((1 << time_shift) - 1);
63 delta = time_offset + quot * time_mult +
64 ((rem * time_mult) >> time_shift);
70 quot = count / running;
71 rem = count % running;
72 count = quot * enabled + (rem * enabled) / running;
79 * If the RDPMC instruction faults then signal this back to the test parent task:
81 static void segfault_handler(int sig __maybe_unused,
82 siginfo_t *info __maybe_unused,
83 void *uc __maybe_unused)
88 static int __test__rdpmc(void)
95 struct perf_event_attr attr = {
96 .type = PERF_TYPE_HARDWARE,
97 .config = PERF_COUNT_HW_INSTRUCTIONS,
103 sigfillset(&sa.sa_mask);
104 sa.sa_sigaction = segfault_handler;
105 sigaction(SIGSEGV, &sa, NULL);
107 fd = sys_perf_event_open(&attr, 0, -1, -1, 0);
109 pr_err("Error: sys_perf_event_open() syscall returned "
110 "with %d (%s)\n", fd, strerror(errno));
114 addr = mmap(NULL, page_size, PROT_READ, MAP_SHARED, fd, 0);
115 if (addr == (void *)(-1)) {
116 pr_err("Error: mmap() syscall returned with (%s)\n",
121 for (n = 0; n < 6; n++) {
122 u64 stamp, now, delta;
124 stamp = mmap_read_self(addr);
126 for (i = 0; i < loops; i++)
129 now = mmap_read_self(addr);
133 pr_debug("%14d: %14Lu\n", n, (long long)delta);
138 munmap(addr, page_size);
149 int test__rdpmc(void)
161 ret = __test__rdpmc();
166 wret = waitpid(pid, &status, 0);
167 if (wret < 0 || status)