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
 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
103	sigfillset(&sa.sa_mask);
104	sa.sa_sigaction = segfault_handler;
105	sigaction(SIGSEGV, &sa, NULL);
106
107	fd = sys_perf_event_open(&attr, 0, -1, -1, 0);
108	if (fd < 0) {
109		pr_err("Error: sys_perf_event_open() syscall returned "
110		       "with %d (%s)\n", fd, strerror(errno));
111		return -1;
112	}
113
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",
117		       strerror(errno));
118		goto out_close;
119	}
120
121	for (n = 0; n < 6; n++) {
122		u64 stamp, now, delta;
123
124		stamp = mmap_read_self(addr);
125
126		for (i = 0; i < loops; i++)
127			tmp++;
128
129		now = mmap_read_self(addr);
130		loops *= 10;
131
132		delta = now - stamp;
133		pr_debug("%14d: %14Lu\n", n, (long long)delta);
134
135		delta_sum += delta;
136	}
137
138	munmap(addr, page_size);
139	pr_debug("   ");
140out_close:
141	close(fd);
142
143	if (!delta_sum)
144		return -1;
145
146	return 0;
147}
148
149int test__rdpmc(void)
150{
151	int status = 0;
152	int wret = 0;
153	int ret;
154	int pid;
155
156	pid = fork();
157	if (pid < 0)
158		return -1;
159
160	if (!pid) {
161		ret = __test__rdpmc();
162
163		exit(ret);
164	}
165
166	wret = waitpid(pid, &status, 0);
167	if (wret < 0 || status)
168		return -1;
169
170	return 0;
171}
172
173#endif