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