selftests/bpf: add bpf_spin_lock C test

add bpf_spin_lock C based test that requires latest llvm with BTF support
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

tools/testing/selftests/bpf/Makefile

@@ -35,7 +35,7 @@ BPF_OBJ_FILES = \
 	sendmsg4_prog.o sendmsg6_prog.o test_lirc_mode2_kern.o \
 	get_cgroup_id_kern.o socket_cookie_prog.o test_select_reuseport_kern.o \
 	test_skb_cgroup_id_kern.o bpf_flow.o netcnt_prog.o test_xdp_vlan.o \
-	xdp_dummy.o test_map_in_map.o
+	xdp_dummy.o test_map_in_map.o test_spin_lock.o
 
 # Objects are built with default compilation flags and with sub-register
 # code-gen enabled.

tools/testing/selftests/bpf/bpf_helpers.h

@@ -172,6 +172,10 @@ static int (*bpf_skb_vlan_pop)(void *ctx) =
 	(void *) BPF_FUNC_skb_vlan_pop;
 static int (*bpf_rc_pointer_rel)(void *ctx, int rel_x, int rel_y) =
 	(void *) BPF_FUNC_rc_pointer_rel;
+static void (*bpf_spin_lock)(struct bpf_spin_lock *lock) =
+	(void *) BPF_FUNC_spin_lock;
+static void (*bpf_spin_unlock)(struct bpf_spin_lock *lock) =
+	(void *) BPF_FUNC_spin_unlock;
 
 /* llvm builtin functions that eBPF C program may use to
  * emit BPF_LD_ABS and BPF_LD_IND instructions

tools/testing/selftests/bpf/test_progs.c

@@ -28,7 +28,7 @@ typedef __u16 __sum16;
 #include <sys/wait.h>
 #include <sys/types.h>
 #include <fcntl.h>
-
+#include <pthread.h>
 #include <linux/bpf.h>
 #include <linux/err.h>
 #include <bpf/bpf.h>
@@ -1985,6 +1985,46 @@ static void test_flow_dissector(void)
 	bpf_object__close(obj);
 }
 
+static void *test_spin_lock(void *arg)
+{
+	__u32 duration, retval;
+	int err, prog_fd = *(u32 *) arg;
+
+	err = bpf_prog_test_run(prog_fd, 10000, &pkt_v4, sizeof(pkt_v4),
+				NULL, NULL, &retval, &duration);
+	CHECK(err || retval, "",
+	      "err %d errno %d retval %d duration %d\n",
+	      err, errno, retval, duration);
+	pthread_exit(arg);
+}
+
+static void test_spinlock(void)
+{
+	const char *file = "./test_spin_lock.o";
+	pthread_t thread_id[4];
+	struct bpf_object *obj;
+	int prog_fd;
+	int err = 0, i;
+	void *ret;
+
+	err = bpf_prog_load(file, BPF_PROG_TYPE_CGROUP_SKB, &obj, &prog_fd);
+	if (err) {
+		printf("test_spin_lock:bpf_prog_load errno %d\n", errno);
+		goto close_prog;
+	}
+	for (i = 0; i < 4; i++)
+		assert(pthread_create(&thread_id[i], NULL,
+				      &test_spin_lock, &prog_fd) == 0);
+	for (i = 0; i < 4; i++)
+		assert(pthread_join(thread_id[i], &ret) == 0 &&
+		       ret == (void *)&prog_fd);
+	goto close_prog_noerr;
+close_prog:
+	error_cnt++;
+close_prog_noerr:
+	bpf_object__close(obj);
+}
+
 int main(void)
 {
 	srand(time(NULL));
@@ -2013,6 +2053,7 @@ int main(void)
 	test_queue_stack_map(QUEUE);
 	test_queue_stack_map(STACK);
 	test_flow_dissector();
+	test_spinlock();
 
 	printf("Summary: %d PASSED, %d FAILED\n", pass_cnt, error_cnt);
 	return error_cnt ? EXIT_FAILURE : EXIT_SUCCESS;

tools/testing/selftests/bpf/test_spin_lock.c

+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2019 Facebook
+#include <linux/bpf.h>
+#include <linux/version.h>
+#include "bpf_helpers.h"
+
+struct hmap_elem {
+	volatile int cnt;
+	struct bpf_spin_lock lock;
+	int test_padding;
+};
+
+struct bpf_map_def SEC("maps") hmap = {
+	.type = BPF_MAP_TYPE_HASH,
+	.key_size = sizeof(int),
+	.value_size = sizeof(struct hmap_elem),
+	.max_entries = 1,
+};
+
+BPF_ANNOTATE_KV_PAIR(hmap, int, struct hmap_elem);
+
+
+struct cls_elem {
+	struct bpf_spin_lock lock;
+	volatile int cnt;
+};
+
+struct bpf_map_def SEC("maps") cls_map = {
+	.type = BPF_MAP_TYPE_CGROUP_STORAGE,
+	.key_size = sizeof(struct bpf_cgroup_storage_key),
+	.value_size = sizeof(struct cls_elem),
+};
+
+BPF_ANNOTATE_KV_PAIR(cls_map, struct bpf_cgroup_storage_key,
+		     struct cls_elem);
+
+struct bpf_vqueue {
+	struct bpf_spin_lock lock;
+	/* 4 byte hole */
+	unsigned long long lasttime;
+	int credit;
+	unsigned int rate;
+};
+
+struct bpf_map_def SEC("maps") vqueue = {
+	.type = BPF_MAP_TYPE_ARRAY,
+	.key_size = sizeof(int),
+	.value_size = sizeof(struct bpf_vqueue),
+	.max_entries = 1,
+};
+
+BPF_ANNOTATE_KV_PAIR(vqueue, int, struct bpf_vqueue);
+#define CREDIT_PER_NS(delta, rate) (((delta) * rate) >> 20)
+
+SEC("spin_lock_demo")
+int bpf_sping_lock_test(struct __sk_buff *skb)
+{
+	volatile int credit = 0, max_credit = 100, pkt_len = 64;
+	struct hmap_elem zero = {}, *val;
+	unsigned long long curtime;
+	struct bpf_vqueue *q;
+	struct cls_elem *cls;
+	int key = 0;
+	int err = 0;
+
+	val = bpf_map_lookup_elem(&hmap, &key);
+	if (!val) {
+		bpf_map_update_elem(&hmap, &key, &zero, 0);
+		val = bpf_map_lookup_elem(&hmap, &key);
+		if (!val) {
+			err = 1;
+			goto err;
+		}
+	}
+	/* spin_lock in hash map run time test */
+	bpf_spin_lock(&val->lock);
+	if (val->cnt)
+		val->cnt--;
+	else
+		val->cnt++;
+	if (val->cnt != 0 && val->cnt != 1)
+		err = 1;
+	bpf_spin_unlock(&val->lock);
+
+	/* spin_lock in array. virtual queue demo */
+	q = bpf_map_lookup_elem(&vqueue, &key);
+	if (!q)
+		goto err;
+	curtime = bpf_ktime_get_ns();
+	bpf_spin_lock(&q->lock);
+	q->credit += CREDIT_PER_NS(curtime - q->lasttime, q->rate);
+	q->lasttime = curtime;
+	if (q->credit > max_credit)
+		q->credit = max_credit;
+	q->credit -= pkt_len;
+	credit = q->credit;
+	bpf_spin_unlock(&q->lock);
+
+	/* spin_lock in cgroup local storage */
+	cls = bpf_get_local_storage(&cls_map, 0);
+	bpf_spin_lock(&cls->lock);
+	cls->cnt++;
+	bpf_spin_unlock(&cls->lock);
+
+err:
+	return err;
+}
+char _license[] SEC("license") = "GPL";