tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (c) 2020 Facebook */
3#include <linux/btf.h>
4#include <linux/btf_ids.h>
5#include <linux/error-injection.h>
6#include <linux/init.h>
7#include <linux/module.h>
8#include <linux/percpu-defs.h>
9#include <linux/sysfs.h>
10#include <linux/tracepoint.h>
11#include "bpf_testmod.h"
12
13#define CREATE_TRACE_POINTS
14#include "bpf_testmod-events.h"
15
16typedef int (*func_proto_typedef)(long);
17typedef int (*func_proto_typedef_nested1)(func_proto_typedef);
18typedef int (*func_proto_typedef_nested2)(func_proto_typedef_nested1);
19
20DEFINE_PER_CPU(int, bpf_testmod_ksym_percpu) = 123;
21
22noinline void
23bpf_testmod_test_mod_kfunc(int i)
24{
25 *(int *)this_cpu_ptr(&bpf_testmod_ksym_percpu) = i;
26}
27
28struct bpf_testmod_btf_type_tag_1 {
29 int a;
30};
31
32struct bpf_testmod_btf_type_tag_2 {
33 struct bpf_testmod_btf_type_tag_1 __user *p;
34};
35
36struct bpf_testmod_btf_type_tag_3 {
37 struct bpf_testmod_btf_type_tag_1 __percpu *p;
38};
39
40noinline int
41bpf_testmod_test_btf_type_tag_user_1(struct bpf_testmod_btf_type_tag_1 __user *arg) {
42 BTF_TYPE_EMIT(func_proto_typedef);
43 BTF_TYPE_EMIT(func_proto_typedef_nested1);
44 BTF_TYPE_EMIT(func_proto_typedef_nested2);
45 return arg->a;
46}
47
48noinline int
49bpf_testmod_test_btf_type_tag_user_2(struct bpf_testmod_btf_type_tag_2 *arg) {
50 return arg->p->a;
51}
52
53noinline int
54bpf_testmod_test_btf_type_tag_percpu_1(struct bpf_testmod_btf_type_tag_1 __percpu *arg) {
55 return arg->a;
56}
57
58noinline int
59bpf_testmod_test_btf_type_tag_percpu_2(struct bpf_testmod_btf_type_tag_3 *arg) {
60 return arg->p->a;
61}
62
63noinline int bpf_testmod_loop_test(int n)
64{
65 int i, sum = 0;
66
67 /* the primary goal of this test is to test LBR. Create a lot of
68 * branches in the function, so we can catch it easily.
69 */
70 for (i = 0; i < n; i++)
71 sum += i;
72 return sum;
73}
74
75__weak noinline struct file *bpf_testmod_return_ptr(int arg)
76{
77 static struct file f = {};
78
79 switch (arg) {
80 case 1: return (void *)EINVAL; /* user addr */
81 case 2: return (void *)0xcafe4a11; /* user addr */
82 case 3: return (void *)-EINVAL; /* canonical, but invalid */
83 case 4: return (void *)(1ull << 60); /* non-canonical and invalid */
84 case 5: return (void *)~(1ull << 30); /* trigger extable */
85 case 6: return &f; /* valid addr */
86 case 7: return (void *)((long)&f | 1); /* kernel tricks */
87 default: return NULL;
88 }
89}
90
91noinline ssize_t
92bpf_testmod_test_read(struct file *file, struct kobject *kobj,
93 struct bin_attribute *bin_attr,
94 char *buf, loff_t off, size_t len)
95{
96 struct bpf_testmod_test_read_ctx ctx = {
97 .buf = buf,
98 .off = off,
99 .len = len,
100 };
101 int i = 1;
102
103 while (bpf_testmod_return_ptr(i))
104 i++;
105
106 /* This is always true. Use the check to make sure the compiler
107 * doesn't remove bpf_testmod_loop_test.
108 */
109 if (bpf_testmod_loop_test(101) > 100)
110 trace_bpf_testmod_test_read(current, &ctx);
111
112 /* Magic number to enable writable tp */
113 if (len == 64) {
114 struct bpf_testmod_test_writable_ctx writable = {
115 .val = 1024,
116 };
117 trace_bpf_testmod_test_writable_bare(&writable);
118 if (writable.early_ret)
119 return snprintf(buf, len, "%d\n", writable.val);
120 }
121
122 return -EIO; /* always fail */
123}
124EXPORT_SYMBOL(bpf_testmod_test_read);
125ALLOW_ERROR_INJECTION(bpf_testmod_test_read, ERRNO);
126
127noinline ssize_t
128bpf_testmod_test_write(struct file *file, struct kobject *kobj,
129 struct bin_attribute *bin_attr,
130 char *buf, loff_t off, size_t len)
131{
132 struct bpf_testmod_test_write_ctx ctx = {
133 .buf = buf,
134 .off = off,
135 .len = len,
136 };
137
138 trace_bpf_testmod_test_write_bare(current, &ctx);
139
140 return -EIO; /* always fail */
141}
142EXPORT_SYMBOL(bpf_testmod_test_write);
143ALLOW_ERROR_INJECTION(bpf_testmod_test_write, ERRNO);
144
145static struct bin_attribute bin_attr_bpf_testmod_file __ro_after_init = {
146 .attr = { .name = "bpf_testmod", .mode = 0666, },
147 .read = bpf_testmod_test_read,
148 .write = bpf_testmod_test_write,
149};
150
151BTF_SET_START(bpf_testmod_check_kfunc_ids)
152BTF_ID(func, bpf_testmod_test_mod_kfunc)
153BTF_SET_END(bpf_testmod_check_kfunc_ids)
154
155static const struct btf_kfunc_id_set bpf_testmod_kfunc_set = {
156 .owner = THIS_MODULE,
157 .check_set = &bpf_testmod_check_kfunc_ids,
158};
159
160extern int bpf_fentry_test1(int a);
161
162static int bpf_testmod_init(void)
163{
164 int ret;
165
166 ret = register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_CLS, &bpf_testmod_kfunc_set);
167 if (ret < 0)
168 return ret;
169 if (bpf_fentry_test1(0) < 0)
170 return -EINVAL;
171 return sysfs_create_bin_file(kernel_kobj, &bin_attr_bpf_testmod_file);
172}
173
174static void bpf_testmod_exit(void)
175{
176 return sysfs_remove_bin_file(kernel_kobj, &bin_attr_bpf_testmod_file);
177}
178
179module_init(bpf_testmod_init);
180module_exit(bpf_testmod_exit);
181
182MODULE_AUTHOR("Andrii Nakryiko");
183MODULE_DESCRIPTION("BPF selftests module");
184MODULE_LICENSE("Dual BSD/GPL");