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.h"
9#include "cloexec.h"
10
11#if defined(__x86_64__) || defined(__i386__)
12
13static u64 rdpmc(unsigned int counter)
14{
15	unsigned int low, high;
16
17	asm volatile("rdpmc" : "=a" (low), "=d" (high) : "c" (counter));
18
19	return low | ((u64)high) << 32;
20}
21
22static u64 rdtsc(void)
23{
24	unsigned int low, high;
25
26	asm volatile("rdtsc" : "=a" (low), "=d" (high));
27
28	return low | ((u64)high) << 32;
29}
30
31static u64 mmap_read_self(void *addr)
32{
33	struct perf_event_mmap_page *pc = addr;
34	u32 seq, idx, time_mult = 0, time_shift = 0;
35	u64 count, cyc = 0, time_offset = 0, enabled, running, delta;
36
37	do {
38		seq = pc->lock;
39		barrier();
40
41		enabled = pc->time_enabled;
42		running = pc->time_running;
43
44		if (enabled != running) {
45			cyc = rdtsc();
46			time_mult = pc->time_mult;
47			time_shift = pc->time_shift;
48			time_offset = pc->time_offset;
49		}
50
51		idx = pc->index;
52		count = pc->offset;
53		if (idx)
54			count += rdpmc(idx - 1);
55
56		barrier();
57	} while (pc->lock != seq);
58
59	if (enabled != running) {
60		u64 quot, rem;
61
62		quot = (cyc >> time_shift);
63		rem = cyc & ((1 << time_shift) - 1);
64		delta = time_offset + quot * time_mult +
65			((rem * time_mult) >> time_shift);
66
67		enabled += delta;
68		if (idx)
69			running += delta;
70
71		quot = count / running;
72		rem = count % running;
73		count = quot * enabled + (rem * enabled) / running;
74	}
75
76	return count;
77}
78
79/*
80 * If the RDPMC instruction faults then signal this back to the test parent task:
81 */
82static void segfault_handler(int sig __maybe_unused,
83			     siginfo_t *info __maybe_unused,
84			     void *uc __maybe_unused)
85{
86	exit(-1);
87}
88
89static int __test__rdpmc(void)
90{
91	volatile int tmp = 0;
92	u64 i, loops = 1000;
93	int n;
94	int fd;
95	void *addr;
96	struct perf_event_attr attr = {
97		.type = PERF_TYPE_HARDWARE,
98		.config = PERF_COUNT_HW_INSTRUCTIONS,
99		.exclude_kernel = 1,
100	};
101	u64 delta_sum = 0;
102        struct sigaction sa;
103	char sbuf[STRERR_BUFSIZE];
104
105	sigfillset(&sa.sa_mask);
106	sa.sa_sigaction = segfault_handler;
107	sigaction(SIGSEGV, &sa, NULL);
108
109	fd = sys_perf_event_open(&attr, 0, -1, -1,
110				 perf_event_open_cloexec_flag());
111	if (fd < 0) {
112		pr_err("Error: sys_perf_event_open() syscall returned "
113		       "with %d (%s)\n", fd,
114		       strerror_r(errno, sbuf, sizeof(sbuf)));
115		return -1;
116	}
117
118	addr = mmap(NULL, page_size, PROT_READ, MAP_SHARED, fd, 0);
119	if (addr == (void *)(-1)) {
120		pr_err("Error: mmap() syscall returned with (%s)\n",
121		       strerror_r(errno, sbuf, sizeof(sbuf)));
122		goto out_close;
123	}
124
125	for (n = 0; n < 6; n++) {
126		u64 stamp, now, delta;
127
128		stamp = mmap_read_self(addr);
129
130		for (i = 0; i < loops; i++)
131			tmp++;
132
133		now = mmap_read_self(addr);
134		loops *= 10;
135
136		delta = now - stamp;
137		pr_debug("%14d: %14Lu\n", n, (long long)delta);
138
139		delta_sum += delta;
140	}
141
142	munmap(addr, page_size);
143	pr_debug("   ");
144out_close:
145	close(fd);
146
147	if (!delta_sum)
148		return -1;
149
150	return 0;
151}
152
153int test__rdpmc(void)
154{
155	int status = 0;
156	int wret = 0;
157	int ret;
158	int pid;
159
160	pid = fork();
161	if (pid < 0)
162		return -1;
163
164	if (!pid) {
165		ret = __test__rdpmc();
166
167		exit(ret);
168	}
169
170	wret = waitpid(pid, &status, 0);
171	if (wret < 0 || status)
172		return -1;
173
174	return 0;
175}
176
177#endif
178