1 // SPDX-License-Identifier: GPL-2.0
9 #include <linux/types.h>
12 #include "tests/tests.h"
15 #include "arch-tests.h"
17 static u64 rdpmc(unsigned int counter)
19 unsigned int low, high;
21 asm volatile("rdpmc" : "=a" (low), "=d" (high) : "c" (counter));
23 return low | ((u64)high) << 32;
26 static u64 rdtsc(void)
28 unsigned int low, high;
30 asm volatile("rdtsc" : "=a" (low), "=d" (high));
32 return low | ((u64)high) << 32;
35 static u64 mmap_read_self(void *addr)
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;
45 enabled = pc->time_enabled;
46 running = pc->time_running;
48 if (enabled != running) {
50 time_mult = pc->time_mult;
51 time_shift = pc->time_shift;
52 time_offset = pc->time_offset;
58 count += rdpmc(idx - 1);
61 } while (pc->lock != seq);
63 if (enabled != running) {
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);
75 quot = count / running;
76 rem = count % running;
77 count = quot * enabled + (rem * enabled) / running;
84 * If the RDPMC instruction faults then signal this back to the test parent task:
86 static void segfault_handler(int sig __maybe_unused,
87 siginfo_t *info __maybe_unused,
88 void *uc __maybe_unused)
93 static int __test__rdpmc(void)
100 struct perf_event_attr attr = {
101 .type = PERF_TYPE_HARDWARE,
102 .config = PERF_COUNT_HW_INSTRUCTIONS,
107 char sbuf[STRERR_BUFSIZE];
109 sigfillset(&sa.sa_mask);
110 sa.sa_sigaction = segfault_handler;
112 sigaction(SIGSEGV, &sa, NULL);
114 fd = sys_perf_event_open(&attr, 0, -1, -1,
115 perf_event_open_cloexec_flag());
117 pr_err("Error: sys_perf_event_open() syscall returned "
118 "with %d (%s)\n", fd,
119 str_error_r(errno, sbuf, sizeof(sbuf)));
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)));
130 for (n = 0; n < 6; n++) {
131 u64 stamp, now, delta;
133 stamp = mmap_read_self(addr);
135 for (i = 0; i < loops; i++)
138 now = mmap_read_self(addr);
142 pr_debug("%14d: %14Lu\n", n, (long long)delta);
147 munmap(addr, page_size);
158 int test__rdpmc(struct test *test __maybe_unused, int subtest __maybe_unused)
170 ret = __test__rdpmc();
175 wret = waitpid(pid, &status, 0);
176 if (wret < 0 || status)