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