1 files changed, 352 insertions, 0 deletions
diff --git a/samples/bpf/trace_event_user.c b/samples/bpf/trace_event_user.c
new file mode 100644
index 000000000..9664749bf
--- /dev/null
+++ b/samples/bpf/trace_event_user.c
@@ -0,0 +1,352 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2016 Facebook
+ */
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+#include <linux/perf_event.h>
+#include <linux/bpf.h>
+#include <signal.h>
+#include <errno.h>
+#include <sys/resource.h>
+#include <bpf/bpf.h>
+#include <bpf/libbpf.h>
+#include "perf-sys.h"
+#include "trace_helpers.h"
+
+#define SAMPLE_FREQ 50
+
+static int pid;
+/* counts, stackmap */
+static int map_fd[2];
+struct bpf_program *prog;
+static bool sys_read_seen, sys_write_seen;
+
+static void print_ksym(__u64 addr)
+{
+	struct ksym *sym;
+
+	if (!addr)
+		return;
+	sym = ksym_search(addr);
+	if (!sym) {
+		printf("ksym not found. Is kallsyms loaded?\n");
+		return;
+	}
+
+	printf("%s;", sym->name);
+	if (!strstr(sym->name, "sys_read"))
+		sys_read_seen = true;
+	else if (!strstr(sym->name, "sys_write"))
+		sys_write_seen = true;
+}
+
+static void print_addr(__u64 addr)
+{
+	if (!addr)
+		return;
+	printf("%llx;", addr);
+}
+
+#define TASK_COMM_LEN 16
+
+struct key_t {
+	char comm[TASK_COMM_LEN];
+	__u32 kernstack;
+	__u32 userstack;
+};
+
+static void print_stack(struct key_t *key, __u64 count)
+{
+	__u64 ip[PERF_MAX_STACK_DEPTH] = {};
+	static bool warned;
+	int i;
+
+	printf("%3lld %s;", count, key->comm);
+	if (bpf_map_lookup_elem(map_fd[1], &key->kernstack, ip) != 0) {
+		printf("---;");
+	} else {
+		for (i = PERF_MAX_STACK_DEPTH - 1; i >= 0; i--)
+			print_ksym(ip[i]);
+	}
+	printf("-;");
+	if (bpf_map_lookup_elem(map_fd[1], &key->userstack, ip) != 0) {
+		printf("---;");
+	} else {
+		for (i = PERF_MAX_STACK_DEPTH - 1; i >= 0; i--)
+			print_addr(ip[i]);
+	}
+	if (count < 6)
+		printf("\r");
+	else
+		printf("\n");
+
+	if (key->kernstack == -EEXIST && !warned) {
+		printf("stackmap collisions seen. Consider increasing size\n");
+		warned = true;
+	} else if ((int)key->kernstack < 0 && (int)key->userstack < 0) {
+		printf("err stackid %d %d\n", key->kernstack, key->userstack);
+	}
+}
+
+static void err_exit(int err)
+{
+	kill(pid, SIGKILL);
+	exit(err);
+}
+
+static void print_stacks(void)
+{
+	struct key_t key = {}, next_key;
+	__u64 value;
+	__u32 stackid = 0, next_id;
+	int error = 1, fd = map_fd[0], stack_map = map_fd[1];
+
+	sys_read_seen = sys_write_seen = false;
+	while (bpf_map_get_next_key(fd, &key, &next_key) == 0) {
+		bpf_map_lookup_elem(fd, &next_key, &value);
+		print_stack(&next_key, value);
+		bpf_map_delete_elem(fd, &next_key);
+		key = next_key;
+	}
+	printf("\n");
+	if (!sys_read_seen || !sys_write_seen) {
+		printf("BUG kernel stack doesn't contain sys_read() and sys_write()\n");
+		err_exit(error);
+	}
+
+	/* clear stack map */
+	while (bpf_map_get_next_key(stack_map, &stackid, &next_id) == 0) {
+		bpf_map_delete_elem(stack_map, &next_id);
+		stackid = next_id;
+	}
+}
+
+static inline int generate_load(void)
+{
+	if (system("dd if=/dev/zero of=/dev/null count=5000k status=none") < 0) {
+		printf("failed to generate some load with dd: %s\n", strerror(errno));
+		return -1;
+	}
+
+	return 0;
+}
+
+static void test_perf_event_all_cpu(struct perf_event_attr *attr)
+{
+	int nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
+	struct bpf_link **links = calloc(nr_cpus, sizeof(struct bpf_link *));
+	int i, pmu_fd, error = 1;
+
+	if (!links) {
+		printf("malloc of links failed\n");
+		goto err;
+	}
+
+	/* system wide perf event, no need to inherit */
+	attr->inherit = 0;
+
+	/* open perf_event on all cpus */
+	for (i = 0; i < nr_cpus; i++) {
+		pmu_fd = sys_perf_event_open(attr, -1, i, -1, 0);
+		if (pmu_fd < 0) {
+			printf("sys_perf_event_open failed\n");
+			goto all_cpu_err;
+		}
+		links[i] = bpf_program__attach_perf_event(prog, pmu_fd);
+		if (libbpf_get_error(links[i])) {
+			printf("bpf_program__attach_perf_event failed\n");
+			links[i] = NULL;
+			close(pmu_fd);
+			goto all_cpu_err;
+		}
+	}
+
+	if (generate_load() < 0)
+		goto all_cpu_err;
+
+	print_stacks();
+	error = 0;
+all_cpu_err:
+	for (i--; i >= 0; i--)
+		bpf_link__destroy(links[i]);
+err:
+	free(links);
+	if (error)
+		err_exit(error);
+}
+
+static void test_perf_event_task(struct perf_event_attr *attr)
+{
+	struct bpf_link *link = NULL;
+	int pmu_fd, error = 1;
+
+	/* per task perf event, enable inherit so the "dd ..." command can be traced properly.
+	 * Enabling inherit will cause bpf_perf_prog_read_time helper failure.
+	 */
+	attr->inherit = 1;
+
+	/* open task bound event */
+	pmu_fd = sys_perf_event_open(attr, 0, -1, -1, 0);
+	if (pmu_fd < 0) {
+		printf("sys_perf_event_open failed\n");
+		goto err;
+	}
+	link = bpf_program__attach_perf_event(prog, pmu_fd);
+	if (libbpf_get_error(link)) {
+		printf("bpf_program__attach_perf_event failed\n");
+		link = NULL;
+		close(pmu_fd);
+		goto err;
+	}
+
+	if (generate_load() < 0)
+		goto err;
+
+	print_stacks();
+	error = 0;
+err:
+	bpf_link__destroy(link);
+	if (error)
+		err_exit(error);
+}
+
+static void test_bpf_perf_event(void)
+{
+	struct perf_event_attr attr_type_hw = {
+		.sample_freq = SAMPLE_FREQ,
+		.freq = 1,
+		.type = PERF_TYPE_HARDWARE,
+		.config = PERF_COUNT_HW_CPU_CYCLES,
+	};
+	struct perf_event_attr attr_type_sw = {
+		.sample_freq = SAMPLE_FREQ,
+		.freq = 1,
+		.type = PERF_TYPE_SOFTWARE,
+		.config = PERF_COUNT_SW_CPU_CLOCK,
+	};
+	struct perf_event_attr attr_hw_cache_l1d = {
+		.sample_freq = SAMPLE_FREQ,
+		.freq = 1,
+		.type = PERF_TYPE_HW_CACHE,
+		.config =
+			PERF_COUNT_HW_CACHE_L1D |
+			(PERF_COUNT_HW_CACHE_OP_READ << 8) |
+			(PERF_COUNT_HW_CACHE_RESULT_ACCESS << 16),
+	};
+	struct perf_event_attr attr_hw_cache_branch_miss = {
+		.sample_freq = SAMPLE_FREQ,
+		.freq = 1,
+		.type = PERF_TYPE_HW_CACHE,
+		.config =
+			PERF_COUNT_HW_CACHE_BPU |
+			(PERF_COUNT_HW_CACHE_OP_READ << 8) |
+			(PERF_COUNT_HW_CACHE_RESULT_MISS << 16),
+	};
+	struct perf_event_attr attr_type_raw = {
+		.sample_freq = SAMPLE_FREQ,
+		.freq = 1,
+		.type = PERF_TYPE_RAW,
+		/* Intel Instruction Retired */
+		.config = 0xc0,
+	};
+	struct perf_event_attr attr_type_raw_lock_load = {
+		.sample_freq = SAMPLE_FREQ,
+		.freq = 1,
+		.type = PERF_TYPE_RAW,
+		/* Intel MEM_UOPS_RETIRED.LOCK_LOADS */
+		.config = 0x21d0,
+		/* Request to record lock address from PEBS */
+		.sample_type = PERF_SAMPLE_ADDR,
+		/* Record address value requires precise event */
+		.precise_ip = 2,
+	};
+
+	printf("Test HW_CPU_CYCLES\n");
+	test_perf_event_all_cpu(&attr_type_hw);
+	test_perf_event_task(&attr_type_hw);
+
+	printf("Test SW_CPU_CLOCK\n");
+	test_perf_event_all_cpu(&attr_type_sw);
+	test_perf_event_task(&attr_type_sw);
+
+	printf("Test HW_CACHE_L1D\n");
+	test_perf_event_all_cpu(&attr_hw_cache_l1d);
+	test_perf_event_task(&attr_hw_cache_l1d);
+
+	printf("Test HW_CACHE_BPU\n");
+	test_perf_event_all_cpu(&attr_hw_cache_branch_miss);
+	test_perf_event_task(&attr_hw_cache_branch_miss);
+
+	printf("Test Instruction Retired\n");
+	test_perf_event_all_cpu(&attr_type_raw);
+	test_perf_event_task(&attr_type_raw);
+
+	printf("Test Lock Load\n");
+	test_perf_event_all_cpu(&attr_type_raw_lock_load);
+	test_perf_event_task(&attr_type_raw_lock_load);
+
+	printf("*** PASS ***\n");
+}
+
+
+int main(int argc, char **argv)
+{
+	struct bpf_object *obj = NULL;
+	char filename[256];
+	int error = 1;
+
+	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
+
+	signal(SIGINT, err_exit);
+	signal(SIGTERM, err_exit);
+
+	if (load_kallsyms()) {
+		printf("failed to process /proc/kallsyms\n");
+		goto cleanup;
+	}
+
+	obj = bpf_object__open_file(filename, NULL);
+	if (libbpf_get_error(obj)) {
+		printf("opening BPF object file failed\n");
+		obj = NULL;
+		goto cleanup;
+	}
+
+	prog = bpf_object__find_program_by_name(obj, "bpf_prog1");
+	if (!prog) {
+		printf("finding a prog in obj file failed\n");
+		goto cleanup;
+	}
+
+	/* load BPF program */
+	if (bpf_object__load(obj)) {
+		printf("loading BPF object file failed\n");
+		goto cleanup;
+	}
+
+	map_fd[0] = bpf_object__find_map_fd_by_name(obj, "counts");
+	map_fd[1] = bpf_object__find_map_fd_by_name(obj, "stackmap");
+	if (map_fd[0] < 0 || map_fd[1] < 0) {
+		printf("finding a counts/stackmap map in obj file failed\n");
+		goto cleanup;
+	}
+
+	pid = fork();
+	if (pid == 0) {
+		read_trace_pipe();
+		return 0;
+	} else if (pid == -1) {
+		printf("couldn't spawn process\n");
+		goto cleanup;
+	}
+
+	test_bpf_perf_event();
+	error = 0;
+
+cleanup:
+	bpf_object__close(obj);
+	err_exit(error);
+}