v4.19.13 snapshot.
diff --git a/samples/bpf/trace_event_user.c b/samples/bpf/trace_event_user.c
new file mode 100644
index 0000000..d08046a
--- /dev/null
+++ b/samples/bpf/trace_event_user.c
@@ -0,0 +1,308 @@
+/* Copyright (c) 2016 Facebook
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ */
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+#include <fcntl.h>
+#include <poll.h>
+#include <sys/ioctl.h>
+#include <linux/perf_event.h>
+#include <linux/bpf.h>
+#include <signal.h>
+#include <assert.h>
+#include <errno.h>
+#include <sys/resource.h>
+#include "libbpf.h"
+#include "bpf_load.h"
+#include "perf-sys.h"
+#include "trace_helpers.h"
+
+#define SAMPLE_FREQ 50
+
+static bool sys_read_seen, sys_write_seen;
+
+static void print_ksym(__u64 addr)
+{
+ struct ksym *sym;
+
+ if (!addr)
+ return;
+ sym = ksym_search(addr);
+ printf("%s;", sym->name);
+ if (!strcmp(sym->name, "sys_read"))
+ sys_read_seen = true;
+ else if (!strcmp(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 int_exit(int sig)
+{
+ kill(0, SIGKILL);
+ exit(0);
+}
+
+static void print_stacks(void)
+{
+ struct key_t key = {}, next_key;
+ __u64 value;
+ __u32 stackid = 0, next_id;
+ int 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");
+ int_exit(0);
+ }
+
+ /* 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_CONF);
+ int *pmu_fd = malloc(nr_cpus * sizeof(int));
+ int i, error = 0;
+
+ /* 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[i] = sys_perf_event_open(attr, -1, i, -1, 0);
+ if (pmu_fd[i] < 0) {
+ printf("sys_perf_event_open failed\n");
+ error = 1;
+ goto all_cpu_err;
+ }
+ assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_SET_BPF, prog_fd[0]) == 0);
+ assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_ENABLE) == 0);
+ }
+
+ if (generate_load() < 0) {
+ error = 1;
+ goto all_cpu_err;
+ }
+ print_stacks();
+all_cpu_err:
+ for (i--; i >= 0; i--) {
+ ioctl(pmu_fd[i], PERF_EVENT_IOC_DISABLE);
+ close(pmu_fd[i]);
+ }
+ free(pmu_fd);
+ if (error)
+ int_exit(0);
+}
+
+static void test_perf_event_task(struct perf_event_attr *attr)
+{
+ int pmu_fd, error = 0;
+
+ /* 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");
+ int_exit(0);
+ }
+ assert(ioctl(pmu_fd, PERF_EVENT_IOC_SET_BPF, prog_fd[0]) == 0);
+ assert(ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE) == 0);
+
+ if (generate_load() < 0) {
+ error = 1;
+ goto err;
+ }
+ print_stacks();
+err:
+ ioctl(pmu_fd, PERF_EVENT_IOC_DISABLE);
+ close(pmu_fd);
+ if (error)
+ int_exit(0);
+}
+
+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 rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
+ char filename[256];
+
+ snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
+ setrlimit(RLIMIT_MEMLOCK, &r);
+
+ signal(SIGINT, int_exit);
+ signal(SIGTERM, int_exit);
+
+ if (load_kallsyms()) {
+ printf("failed to process /proc/kallsyms\n");
+ return 1;
+ }
+
+ if (load_bpf_file(filename)) {
+ printf("%s", bpf_log_buf);
+ return 2;
+ }
+
+ if (fork() == 0) {
+ read_trace_pipe();
+ return 0;
+ }
+ test_bpf_perf_event();
+ int_exit(0);
+ return 0;
+}