1// SPDX-License-Identifier: GPL-2.0
2// Copyright (c) 2019 Facebook
3#include <linux/bpf.h>
4#include <linux/version.h>
5#include <bpf/bpf_helpers.h>
6#include "bpf_misc.h"
7
8struct hmap_elem {
9	volatile int cnt;
10	struct bpf_spin_lock lock;
11	int test_padding;
12};
13
14struct {
15	__uint(type, BPF_MAP_TYPE_HASH);
16	__uint(max_entries, 1);
17	__type(key, int);
18	__type(value, struct hmap_elem);
19} hmap SEC(".maps");
20
21struct cls_elem {
22	struct bpf_spin_lock lock;
23	volatile int cnt;
24};
25
26struct {
27	__uint(type, BPF_MAP_TYPE_CGROUP_STORAGE);
28	__type(key, struct bpf_cgroup_storage_key);
29	__type(value, struct cls_elem);
30} cls_map SEC(".maps");
31
32struct bpf_vqueue {
33	struct bpf_spin_lock lock;
34	/* 4 byte hole */
35	unsigned long long lasttime;
36	int credit;
37	unsigned int rate;
38};
39
40struct {
41	__uint(type, BPF_MAP_TYPE_ARRAY);
42	__uint(max_entries, 1);
43	__type(key, int);
44	__type(value, struct bpf_vqueue);
45} vqueue SEC(".maps");
46
47#define CREDIT_PER_NS(delta, rate) (((delta) * rate) >> 20)
48
49SEC("cgroup_skb/ingress")
50int bpf_spin_lock_test(struct __sk_buff *skb)
51{
52	volatile int credit = 0, max_credit = 100, pkt_len = 64;
53	struct hmap_elem zero = {}, *val;
54	unsigned long long curtime;
55	struct bpf_vqueue *q;
56	struct cls_elem *cls;
57	int key = 0;
58	int err = 0;
59
60	val = bpf_map_lookup_elem(&hmap, &key);
61	if (!val) {
62		bpf_map_update_elem(&hmap, &key, &zero, 0);
63		val = bpf_map_lookup_elem(&hmap, &key);
64		if (!val) {
65			err = 1;
66			goto err;
67		}
68	}
69	/* spin_lock in hash map run time test */
70	bpf_spin_lock(&val->lock);
71	if (val->cnt)
72		val->cnt--;
73	else
74		val->cnt++;
75	if (val->cnt != 0 && val->cnt != 1)
76		err = 1;
77	bpf_spin_unlock(&val->lock);
78
79	/* spin_lock in array. virtual queue demo */
80	q = bpf_map_lookup_elem(&vqueue, &key);
81	if (!q)
82		goto err;
83	curtime = bpf_ktime_get_ns();
84	bpf_spin_lock(&q->lock);
85	q->credit += CREDIT_PER_NS(curtime - q->lasttime, q->rate);
86	q->lasttime = curtime;
87	if (q->credit > max_credit)
88		q->credit = max_credit;
89	q->credit -= pkt_len;
90	credit = q->credit;
91	bpf_spin_unlock(&q->lock);
92
93	__sink(credit);
94
95	/* spin_lock in cgroup local storage */
96	cls = bpf_get_local_storage(&cls_map, 0);
97	bpf_spin_lock(&cls->lock);
98	cls->cnt++;
99	bpf_spin_unlock(&cls->lock);
100
101err:
102	return err;
103}
104
105struct bpf_spin_lock lockA __hidden SEC(".data.A");
106
107__noinline
108static int static_subprog(struct __sk_buff *ctx)
109{
110	volatile int ret = 0;
111
112	if (ctx->protocol)
113		return ret;
114	return ret + ctx->len;
115}
116
117__noinline
118static int static_subprog_lock(struct __sk_buff *ctx)
119{
120	volatile int ret = 0;
121
122	ret = static_subprog(ctx);
123	bpf_spin_lock(&lockA);
124	return ret + ctx->len;
125}
126
127__noinline
128static int static_subprog_unlock(struct __sk_buff *ctx)
129{
130	volatile int ret = 0;
131
132	ret = static_subprog(ctx);
133	bpf_spin_unlock(&lockA);
134	return ret + ctx->len;
135}
136
137SEC("tc")
138int lock_static_subprog_call(struct __sk_buff *ctx)
139{
140	int ret = 0;
141
142	bpf_spin_lock(&lockA);
143	if (ctx->mark == 42)
144		ret = static_subprog(ctx);
145	bpf_spin_unlock(&lockA);
146	return ret;
147}
148
149SEC("tc")
150int lock_static_subprog_lock(struct __sk_buff *ctx)
151{
152	int ret = 0;
153
154	ret = static_subprog_lock(ctx);
155	bpf_spin_unlock(&lockA);
156	return ret;
157}
158
159SEC("tc")
160int lock_static_subprog_unlock(struct __sk_buff *ctx)
161{
162	int ret = 0;
163
164	bpf_spin_lock(&lockA);
165	ret = static_subprog_unlock(ctx);
166	return ret;
167}
168
169char _license[] SEC("license") = "GPL";
170