v4.19.13 snapshot.
diff --git a/samples/bpf/syscall_tp_user.c b/samples/bpf/syscall_tp_user.c
new file mode 100644
index 0000000..1a1d005
--- /dev/null
+++ b/samples/bpf/syscall_tp_user.c
@@ -0,0 +1,111 @@
+/* Copyright (c) 2017 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 <fcntl.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <linux/bpf.h>
+#include <string.h>
+#include <linux/perf_event.h>
+#include <errno.h>
+#include <assert.h>
+#include <stdbool.h>
+#include <sys/resource.h>
+#include <bpf/bpf.h>
+#include "bpf_load.h"
+
+/* This program verifies bpf attachment to tracepoint sys_enter_* and sys_exit_*.
+ * This requires kernel CONFIG_FTRACE_SYSCALLS to be set.
+ */
+
+static void usage(const char *cmd)
+{
+ printf("USAGE: %s [-i num_progs] [-h]\n", cmd);
+ printf(" -i num_progs # number of progs of the test\n");
+ printf(" -h # help\n");
+}
+
+static void verify_map(int map_id)
+{
+ __u32 key = 0;
+ __u32 val;
+
+ if (bpf_map_lookup_elem(map_id, &key, &val) != 0) {
+ fprintf(stderr, "map_lookup failed: %s\n", strerror(errno));
+ return;
+ }
+ if (val == 0) {
+ fprintf(stderr, "failed: map #%d returns value 0\n", map_id);
+ return;
+ }
+ val = 0;
+ if (bpf_map_update_elem(map_id, &key, &val, BPF_ANY) != 0) {
+ fprintf(stderr, "map_update failed: %s\n", strerror(errno));
+ return;
+ }
+}
+
+static int test(char *filename, int num_progs)
+{
+ int i, fd, map0_fds[num_progs], map1_fds[num_progs];
+
+ for (i = 0; i < num_progs; i++) {
+ if (load_bpf_file(filename)) {
+ fprintf(stderr, "%s", bpf_log_buf);
+ return 1;
+ }
+ printf("prog #%d: map ids %d %d\n", i, map_fd[0], map_fd[1]);
+ map0_fds[i] = map_fd[0];
+ map1_fds[i] = map_fd[1];
+ }
+
+ /* current load_bpf_file has perf_event_open default pid = -1
+ * and cpu = 0, which permits attached bpf execution on
+ * all cpus for all pid's. bpf program execution ignores
+ * cpu affinity.
+ */
+ /* trigger some "open" operations */
+ fd = open(filename, O_RDONLY);
+ if (fd < 0) {
+ fprintf(stderr, "open failed: %s\n", strerror(errno));
+ return 1;
+ }
+ close(fd);
+
+ /* verify the map */
+ for (i = 0; i < num_progs; i++) {
+ verify_map(map0_fds[i]);
+ verify_map(map1_fds[i]);
+ }
+
+ return 0;
+}
+
+int main(int argc, char **argv)
+{
+ struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
+ int opt, num_progs = 1;
+ char filename[256];
+
+ while ((opt = getopt(argc, argv, "i:h")) != -1) {
+ switch (opt) {
+ case 'i':
+ num_progs = atoi(optarg);
+ break;
+ case 'h':
+ default:
+ usage(argv[0]);
+ return 0;
+ }
+ }
+
+ setrlimit(RLIMIT_MEMLOCK, &r);
+ snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
+
+ return test(filename, num_progs);
+}