1// SPDX-License-Identifier: GPL-2.0-only
  2/* Copyright (c) 2016 Facebook
  3 */
  4#include <stdio.h>
  5#include <unistd.h>
  6#include <stdlib.h>
  7#include <stdbool.h>
  8#include <string.h>
  9#include <linux/perf_event.h>
 10#include <linux/bpf.h>
 11#include <signal.h>
 12#include <errno.h>
 13#include <sys/resource.h>
 14#include <bpf/bpf.h>
 15#include <bpf/libbpf.h>
 16#include "perf-sys.h"
 17#include "trace_helpers.h"
 18
 19#define SAMPLE_FREQ 50
 20
 21static int pid;
 22/* counts, stackmap */
 23static int map_fd[2];
 24struct bpf_program *prog;
 25static bool sys_read_seen, sys_write_seen;
 26
 27static void print_ksym(__u64 addr)
 28{
 29	struct ksym *sym;
 30
 31	if (!addr)
 32		return;
 33	sym = ksym_search(addr);
 34	if (!sym) {
 35		printf("ksym not found. Is kallsyms loaded?\n");
 36		return;
 37	}
 38
 39	printf("%s;", sym->name);
 40	if (!strstr(sym->name, "sys_read"))
 41		sys_read_seen = true;
 42	else if (!strstr(sym->name, "sys_write"))
 43		sys_write_seen = true;
 44}
 45
 46static void print_addr(__u64 addr)
 47{
 48	if (!addr)
 49		return;
 50	printf("%llx;", addr);
 51}
 52
 53#define TASK_COMM_LEN 16
 54
 55struct key_t {
 56	char comm[TASK_COMM_LEN];
 57	__u32 kernstack;
 58	__u32 userstack;
 59};
 60
 61static void print_stack(struct key_t *key, __u64 count)
 62{
 63	__u64 ip[PERF_MAX_STACK_DEPTH] = {};
 64	static bool warned;
 65	int i;
 66
 67	printf("%3lld %s;", count, key->comm);
 68	if (bpf_map_lookup_elem(map_fd[1], &key->kernstack, ip) != 0) {
 69		printf("---;");
 70	} else {
 71		for (i = PERF_MAX_STACK_DEPTH - 1; i >= 0; i--)
 72			print_ksym(ip[i]);
 73	}
 74	printf("-;");
 75	if (bpf_map_lookup_elem(map_fd[1], &key->userstack, ip) != 0) {
 76		printf("---;");
 77	} else {
 78		for (i = PERF_MAX_STACK_DEPTH - 1; i >= 0; i--)
 79			print_addr(ip[i]);
 80	}
 81	if (count < 6)
 82		printf("\r");
 83	else
 84		printf("\n");
 85
 86	if (key->kernstack == -EEXIST && !warned) {
 87		printf("stackmap collisions seen. Consider increasing size\n");
 88		warned = true;
 89	} else if ((int)key->kernstack < 0 && (int)key->userstack < 0) {
 90		printf("err stackid %d %d\n", key->kernstack, key->userstack);
 91	}
 92}
 93
 94static void err_exit(int err)
 95{
 96	kill(pid, SIGKILL);
 97	exit(err);
 98}
 99
100static void print_stacks(void)
101{
102	struct key_t key = {}, next_key;
103	__u64 value;
104	__u32 stackid = 0, next_id;
105	int error = 1, fd = map_fd[0], stack_map = map_fd[1];
106
107	sys_read_seen = sys_write_seen = false;
108	while (bpf_map_get_next_key(fd, &key, &next_key) == 0) {
109		bpf_map_lookup_elem(fd, &next_key, &value);
110		print_stack(&next_key, value);
111		bpf_map_delete_elem(fd, &next_key);
112		key = next_key;
113	}
114	printf("\n");
115	if (!sys_read_seen || !sys_write_seen) {
116		printf("BUG kernel stack doesn't contain sys_read() and sys_write()\n");
117		err_exit(error);
118	}
119
120	/* clear stack map */
121	while (bpf_map_get_next_key(stack_map, &stackid, &next_id) == 0) {
122		bpf_map_delete_elem(stack_map, &next_id);
123		stackid = next_id;
124	}
125}
126
127static inline int generate_load(void)
128{
129	if (system("dd if=/dev/zero of=/dev/null count=5000k status=none") < 0) {
130		printf("failed to generate some load with dd: %s\n", strerror(errno));
131		return -1;
132	}
133
134	return 0;
135}
136
137static void test_perf_event_all_cpu(struct perf_event_attr *attr)
138{
139	int nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
140	struct bpf_link **links = calloc(nr_cpus, sizeof(struct bpf_link *));
141	int i, pmu_fd, error = 1;
142
143	if (!links) {
144		printf("malloc of links failed\n");
145		goto err;
146	}
147
148	/* system wide perf event, no need to inherit */
149	attr->inherit = 0;
150
151	/* open perf_event on all cpus */
152	for (i = 0; i < nr_cpus; i++) {
153		pmu_fd = sys_perf_event_open(attr, -1, i, -1, 0);
154		if (pmu_fd < 0) {
155			printf("sys_perf_event_open failed\n");
156			goto all_cpu_err;
157		}
158		links[i] = bpf_program__attach_perf_event(prog, pmu_fd);
159		if (libbpf_get_error(links[i])) {
160			printf("bpf_program__attach_perf_event failed\n");
161			links[i] = NULL;
162			close(pmu_fd);
163			goto all_cpu_err;
164		}
165	}
166
167	if (generate_load() < 0)
168		goto all_cpu_err;
169
170	print_stacks();
171	error = 0;
172all_cpu_err:
173	for (i--; i >= 0; i--)
174		bpf_link__destroy(links[i]);
175err:
176	free(links);
177	if (error)
178		err_exit(error);
179}
180
181static void test_perf_event_task(struct perf_event_attr *attr)
182{
183	struct bpf_link *link = NULL;
184	int pmu_fd, error = 1;
185
186	/* per task perf event, enable inherit so the "dd ..." command can be traced properly.
187	 * Enabling inherit will cause bpf_perf_prog_read_time helper failure.
188	 */
189	attr->inherit = 1;
190
191	/* open task bound event */
192	pmu_fd = sys_perf_event_open(attr, 0, -1, -1, 0);
193	if (pmu_fd < 0) {
194		printf("sys_perf_event_open failed\n");
195		goto err;
196	}
197	link = bpf_program__attach_perf_event(prog, pmu_fd);
198	if (libbpf_get_error(link)) {
199		printf("bpf_program__attach_perf_event failed\n");
200		link = NULL;
201		close(pmu_fd);
202		goto err;
203	}
204
205	if (generate_load() < 0)
206		goto err;
207
208	print_stacks();
209	error = 0;
210err:
211	bpf_link__destroy(link);
212	if (error)
213		err_exit(error);
214}
215
216static void test_bpf_perf_event(void)
217{
218	struct perf_event_attr attr_type_hw = {
219		.sample_freq = SAMPLE_FREQ,
220		.freq = 1,
221		.type = PERF_TYPE_HARDWARE,
222		.config = PERF_COUNT_HW_CPU_CYCLES,
223	};
224	struct perf_event_attr attr_type_sw = {
225		.sample_freq = SAMPLE_FREQ,
226		.freq = 1,
227		.type = PERF_TYPE_SOFTWARE,
228		.config = PERF_COUNT_SW_CPU_CLOCK,
229	};
230	struct perf_event_attr attr_hw_cache_l1d = {
231		.sample_freq = SAMPLE_FREQ,
232		.freq = 1,
233		.type = PERF_TYPE_HW_CACHE,
234		.config =
235			PERF_COUNT_HW_CACHE_L1D |
236			(PERF_COUNT_HW_CACHE_OP_READ << 8) |
237			(PERF_COUNT_HW_CACHE_RESULT_ACCESS << 16),
238	};
239	struct perf_event_attr attr_hw_cache_branch_miss = {
240		.sample_freq = SAMPLE_FREQ,
241		.freq = 1,
242		.type = PERF_TYPE_HW_CACHE,
243		.config =
244			PERF_COUNT_HW_CACHE_BPU |
245			(PERF_COUNT_HW_CACHE_OP_READ << 8) |
246			(PERF_COUNT_HW_CACHE_RESULT_MISS << 16),
247	};
248	struct perf_event_attr attr_type_raw = {
249		.sample_freq = SAMPLE_FREQ,
250		.freq = 1,
251		.type = PERF_TYPE_RAW,
252		/* Intel Instruction Retired */
253		.config = 0xc0,
254	};
255	struct perf_event_attr attr_type_raw_lock_load = {
256		.sample_freq = SAMPLE_FREQ,
257		.freq = 1,
258		.type = PERF_TYPE_RAW,
259		/* Intel MEM_UOPS_RETIRED.LOCK_LOADS */
260		.config = 0x21d0,
261		/* Request to record lock address from PEBS */
262		.sample_type = PERF_SAMPLE_ADDR,
263		/* Record address value requires precise event */
264		.precise_ip = 2,
265	};
266
267	printf("Test HW_CPU_CYCLES\n");
268	test_perf_event_all_cpu(&attr_type_hw);
269	test_perf_event_task(&attr_type_hw);
270
271	printf("Test SW_CPU_CLOCK\n");
272	test_perf_event_all_cpu(&attr_type_sw);
273	test_perf_event_task(&attr_type_sw);
274
275	printf("Test HW_CACHE_L1D\n");
276	test_perf_event_all_cpu(&attr_hw_cache_l1d);
277	test_perf_event_task(&attr_hw_cache_l1d);
278
279	printf("Test HW_CACHE_BPU\n");
280	test_perf_event_all_cpu(&attr_hw_cache_branch_miss);
281	test_perf_event_task(&attr_hw_cache_branch_miss);
282
283	printf("Test Instruction Retired\n");
284	test_perf_event_all_cpu(&attr_type_raw);
285	test_perf_event_task(&attr_type_raw);
286
287	printf("Test Lock Load\n");
288	test_perf_event_all_cpu(&attr_type_raw_lock_load);
289	test_perf_event_task(&attr_type_raw_lock_load);
290
291	printf("*** PASS ***\n");
292}
293
294
295int main(int argc, char **argv)
296{
297	struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
298	struct bpf_object *obj = NULL;
299	char filename[256];
300	int error = 1;
301
302	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
303	setrlimit(RLIMIT_MEMLOCK, &r);
304
305	signal(SIGINT, err_exit);
306	signal(SIGTERM, err_exit);
307
308	if (load_kallsyms()) {
309		printf("failed to process /proc/kallsyms\n");
310		goto cleanup;
311	}
312
313	obj = bpf_object__open_file(filename, NULL);
314	if (libbpf_get_error(obj)) {
315		printf("opening BPF object file failed\n");
316		obj = NULL;
317		goto cleanup;
318	}
319
320	prog = bpf_object__find_program_by_name(obj, "bpf_prog1");
321	if (!prog) {
322		printf("finding a prog in obj file failed\n");
323		goto cleanup;
324	}
325
326	/* load BPF program */
327	if (bpf_object__load(obj)) {
328		printf("loading BPF object file failed\n");
329		goto cleanup;
330	}
331
332	map_fd[0] = bpf_object__find_map_fd_by_name(obj, "counts");
333	map_fd[1] = bpf_object__find_map_fd_by_name(obj, "stackmap");
334	if (map_fd[0] < 0 || map_fd[1] < 0) {
335		printf("finding a counts/stackmap map in obj file failed\n");
336		goto cleanup;
337	}
338
339	pid = fork();
340	if (pid == 0) {
341		read_trace_pipe();
342		return 0;
343	} else if (pid == -1) {
344		printf("couldn't spawn process\n");
345		goto cleanup;
346	}
347
348	test_bpf_perf_event();
349	error = 0;
350
351cleanup:
352	bpf_object__close(obj);
353	err_exit(error);
354}