change system file

hc

2024-10-09 244b2c5ca8b14627e4a17755e5922221e121c771

 kernel/samples/bpf/trace_output_user.c
..
..
@@ -1,29 +1,10 @@
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-/* This program is free software; you can redistribute it and/or
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- * modify it under the terms of version 2 of the GNU General Public
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- * License as published by the Free Software Foundation.
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- */
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+// SPDX-License-Identifier: GPL-2.0-only
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 #include <stdio.h>
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-#include <unistd.h>
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-#include <stdlib.h>
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-#include <stdbool.h>
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-#include <string.h>
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 #include <fcntl.h>
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 #include <poll.h>
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-#include <linux/perf_event.h>
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-#include <linux/bpf.h>
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-#include <errno.h>
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-#include <assert.h>
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-#include <sys/syscall.h>
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-#include <sys/ioctl.h>
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-#include <sys/mman.h>
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 #include <time.h>
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 #include <signal.h>
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-#include <libbpf.h>
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-#include "bpf_load.h"
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-#include "perf-sys.h"
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-#include "trace_helpers.h"
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-
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-static int pmu_fd;
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+#include <bpf/libbpf.h>
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 static __u64 time_get_ns(void)
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 {
..
..
@@ -34,12 +15,12 @@
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 }
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 static __u64 start_time;
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+static __u64 cnt;
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 #define MAX_CNT 100000ll
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21
 
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-static int print_bpf_output(void *data, int size)
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+static void print_bpf_output(void *ctx, int cpu, void *data, __u32 size)
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 {
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-	static __u64 cnt;
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 	struct {
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 		__u64 pid;
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 		__u64 cookie;
..
..
@@ -48,7 +29,7 @@
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 	if (e->cookie != 0x12345678) {
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 		printf("BUG pid %llx cookie %llx sized %d\n",
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 		       e->pid, e->cookie, size);
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-		return LIBBPF_PERF_EVENT_ERROR;
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+		return;
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 	}
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 	cnt++;
..
..
@@ -56,51 +37,71 @@
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 	if (cnt == MAX_CNT) {
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 		printf("recv %lld events per sec\n",
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 		       MAX_CNT * 1000000000ll / (time_get_ns() - start_time));
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-		return LIBBPF_PERF_EVENT_DONE;
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+		return;
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 	}
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-
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-	return LIBBPF_PERF_EVENT_CONT;
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-}
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-
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-static void test_bpf_perf_event(void)
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-{
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-	struct perf_event_attr attr = {
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-		.sample_type = PERF_SAMPLE_RAW,
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-		.type = PERF_TYPE_SOFTWARE,
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-		.config = PERF_COUNT_SW_BPF_OUTPUT,
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-	};
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-	int key = 0;
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-
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-	pmu_fd = sys_perf_event_open(&attr, -1/*pid*/, 0/*cpu*/, -1/*group_fd*/, 0);
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-
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-	assert(pmu_fd >= 0);
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-	assert(bpf_map_update_elem(map_fd[0], &key, &pmu_fd, BPF_ANY) == 0);
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-	ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0);
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 }
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 int main(int argc, char **argv)
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 {
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+	struct perf_buffer_opts pb_opts = {};
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+	struct bpf_link *link = NULL;
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+	struct bpf_program *prog;
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+	struct perf_buffer *pb;
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+	struct bpf_object *obj;
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+	int map_fd, ret = 0;
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 	char filename[256];
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 	FILE *f;
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-	int ret;
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 	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
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-
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-	if (load_bpf_file(filename)) {
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-		printf("%s", bpf_log_buf);
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-		return 1;
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+	obj = bpf_object__open_file(filename, NULL);
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+	if (libbpf_get_error(obj)) {
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+		fprintf(stderr, "ERROR: opening BPF object file failed\n");
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+		return 0;
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 	}
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-	test_bpf_perf_event();
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+	/* load BPF program */
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+	if (bpf_object__load(obj)) {
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+		fprintf(stderr, "ERROR: loading BPF object file failed\n");
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+		goto cleanup;
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+	}
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-	if (perf_event_mmap(pmu_fd) < 0)
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+	map_fd = bpf_object__find_map_fd_by_name(obj, "my_map");
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+	if (map_fd < 0) {
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+		fprintf(stderr, "ERROR: finding a map in obj file failed\n");
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+		goto cleanup;
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+	}
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+
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+	prog = bpf_object__find_program_by_name(obj, "bpf_prog1");
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+	if (libbpf_get_error(prog)) {
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+		fprintf(stderr, "ERROR: finding a prog in obj file failed\n");
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+		goto cleanup;
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+	}
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+
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+	link = bpf_program__attach(prog);
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+	if (libbpf_get_error(link)) {
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+		fprintf(stderr, "ERROR: bpf_program__attach failed\n");
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+		link = NULL;
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+		goto cleanup;
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+	}
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+
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+	pb_opts.sample_cb = print_bpf_output;
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+	pb = perf_buffer__new(map_fd, 8, &pb_opts);
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+	ret = libbpf_get_error(pb);
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+	if (ret) {
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+		printf("failed to setup perf_buffer: %d\n", ret);
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 		return 1;
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+	}
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 	f = popen("taskset 1 dd if=/dev/zero of=/dev/null", "r");
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 	(void) f;
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 	start_time = time_get_ns();
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-	ret = perf_event_poller(pmu_fd, print_bpf_output);
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+	while ((ret = perf_buffer__poll(pb, 1000)) >= 0 && cnt < MAX_CNT) {
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+	}
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 	kill(0, SIGINT);
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+
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+cleanup:
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+	bpf_link__destroy(link);
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+	bpf_object__close(obj);
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 	return ret;
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 }