1 /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
2 /* Copyright (c) 2021 Hengqi Chen */
3
4 #ifndef __CORE_FIXES_BPF_H
5 #define __CORE_FIXES_BPF_H
6
7 #include <vmlinux.h>
8 #include <bpf/bpf_core_read.h>
9
10 /**
11 * commit 2f064a59a1 ("sched: Change task_struct::state") changes
12 * the name of task_struct::state to task_struct::__state
13 * see:
14 * https://github.com/torvalds/linux/commit/2f064a59a1
15 */
16 struct task_struct___o {
17 volatile long int state;
18 } __attribute__((preserve_access_index));
19
20 struct task_struct___x {
21 unsigned int __state;
22 } __attribute__((preserve_access_index));
23
get_task_state(void * task)24 static __always_inline __s64 get_task_state(void *task)
25 {
26 struct task_struct___x *t = task;
27
28 if (bpf_core_field_exists(t->__state))
29 return BPF_CORE_READ(t, __state);
30 return BPF_CORE_READ((struct task_struct___o *)task, state);
31 }
32
33 /**
34 * commit 309dca309fc3 ("block: store a block_device pointer in struct bio")
35 * adds a new member bi_bdev which is a pointer to struct block_device
36 * see:
37 * https://github.com/torvalds/linux/commit/309dca309fc3
38 */
39 struct bio___o {
40 struct gendisk *bi_disk;
41 } __attribute__((preserve_access_index));
42
43 struct bio___x {
44 struct block_device *bi_bdev;
45 } __attribute__((preserve_access_index));
46
get_gendisk(void * bio)47 static __always_inline struct gendisk *get_gendisk(void *bio)
48 {
49 struct bio___x *b = bio;
50
51 if (bpf_core_field_exists(b->bi_bdev))
52 return BPF_CORE_READ(b, bi_bdev, bd_disk);
53 return BPF_CORE_READ((struct bio___o *)bio, bi_disk);
54 }
55
56 /**
57 * commit d5869fdc189f ("block: introduce block_rq_error tracepoint")
58 * adds a new tracepoint block_rq_error and it shares the same arguments
59 * with tracepoint block_rq_complete. As a result, the kernel BTF now has
60 * a `struct trace_event_raw_block_rq_completion` instead of
61 * `struct trace_event_raw_block_rq_complete`.
62 * see:
63 * https://github.com/torvalds/linux/commit/d5869fdc189f
64 */
65 struct trace_event_raw_block_rq_complete___x {
66 dev_t dev;
67 sector_t sector;
68 unsigned int nr_sector;
69 } __attribute__((preserve_access_index));
70
71 struct trace_event_raw_block_rq_completion___x {
72 dev_t dev;
73 sector_t sector;
74 unsigned int nr_sector;
75 } __attribute__((preserve_access_index));
76
has_block_rq_completion()77 static __always_inline bool has_block_rq_completion()
78 {
79 if (bpf_core_type_exists(struct trace_event_raw_block_rq_completion___x))
80 return true;
81 return false;
82 }
83
84 /**
85 * commit d152c682f03c ("block: add an explicit ->disk backpointer to the
86 * request_queue") and commit f3fa33acca9f ("block: remove the ->rq_disk
87 * field in struct request") make some changes to `struct request` and
88 * `struct request_queue`. Now, to get the `struct gendisk *` field in a CO-RE
89 * way, we need both `struct request` and `struct request_queue`.
90 * see:
91 * https://github.com/torvalds/linux/commit/d152c682f03c
92 * https://github.com/torvalds/linux/commit/f3fa33acca9f
93 */
94 struct request_queue___x {
95 struct gendisk *disk;
96 } __attribute__((preserve_access_index));
97
98 struct request___x {
99 struct request_queue___x *q;
100 struct gendisk *rq_disk;
101 } __attribute__((preserve_access_index));
102
get_disk(void * request)103 static __always_inline struct gendisk *get_disk(void *request)
104 {
105 struct request___x *r = request;
106
107 if (bpf_core_field_exists(r->rq_disk))
108 return BPF_CORE_READ(r, rq_disk);
109 return BPF_CORE_READ(r, q, disk);
110 }
111
112 /**
113 * commit 6521f8917082("namei: prepare for idmapped mounts") add `struct
114 * user_namespace *mnt_userns` as vfs_create() and vfs_unlink() first argument.
115 * At the same time, struct renamedata {} add `struct user_namespace
116 * *old_mnt_userns` item. Now, to kprobe vfs_create()/vfs_unlink() in a CO-RE
117 * way, determine whether there is a `old_mnt_userns` field for `struct
118 * renamedata` to decide which input parameter of the vfs_create() to use as
119 * `dentry`.
120 * commit abf08576afe3("fs: port vfs_*() helpers to struct mnt_idmap") use
121 * `struct mnt_idmap *new_mnt_idmap` instead of `struct user_namespace *
122 * old_mnt_userns`.
123 * see:
124 * https://github.com/torvalds/linux/commit/6521f8917082
125 * https://github.com/torvalds/linux/commit/abf08576afe3
126 */
127 struct renamedata___x {
128 struct user_namespace *old_mnt_userns;
129 struct new_mnt_idmap *new_mnt_idmap;
130 } __attribute__((preserve_access_index));
131
renamedata_has_old_mnt_userns_field(void)132 static __always_inline bool renamedata_has_old_mnt_userns_field(void)
133 {
134 if (bpf_core_field_exists(struct renamedata___x, old_mnt_userns))
135 return true;
136 return false;
137 }
138
renamedata_has_new_mnt_idmap_field(void)139 static __always_inline bool renamedata_has_new_mnt_idmap_field(void)
140 {
141 if (bpf_core_field_exists(struct renamedata___x, new_mnt_idmap))
142 return true;
143 return false;
144 }
145
146 /**
147 * commit 3544de8ee6e4("mm, tracing: record slab name for kmem_cache_free()")
148 * replaces `trace_event_raw_kmem_free` with `trace_event_raw_kfree` and adds
149 * `tracepoint_kmem_cache_free` to enhance the information recorded for
150 * `kmem_cache_free`.
151 * see:
152 * https://github.com/torvalds/linux/commit/3544de8ee6e4
153 */
154
155 struct trace_event_raw_kmem_free___x {
156 const void *ptr;
157 } __attribute__((preserve_access_index));
158
159 struct trace_event_raw_kfree___x {
160 const void *ptr;
161 } __attribute__((preserve_access_index));
162
163 struct trace_event_raw_kmem_cache_free___x {
164 const void *ptr;
165 } __attribute__((preserve_access_index));
166
has_kfree()167 static __always_inline bool has_kfree()
168 {
169 if (bpf_core_type_exists(struct trace_event_raw_kfree___x))
170 return true;
171 return false;
172 }
173
has_kmem_cache_free()174 static __always_inline bool has_kmem_cache_free()
175 {
176 if (bpf_core_type_exists(struct trace_event_raw_kmem_cache_free___x))
177 return true;
178 return false;
179 }
180
181 /**
182 * commit 11e9734bcb6a("mm/slab_common: unify NUMA and UMA version of
183 * tracepoints") drops kmem_alloc event class, rename kmem_alloc_node to
184 * kmem_alloc, so `trace_event_raw_kmem_alloc_node` is not existed any more.
185 * see:
186 * https://github.com/torvalds/linux/commit/11e9734bcb6a
187 */
188 struct trace_event_raw_kmem_alloc_node___x {
189 const void *ptr;
190 size_t bytes_alloc;
191 } __attribute__((preserve_access_index));
192
has_kmem_alloc_node(void)193 static __always_inline bool has_kmem_alloc_node(void)
194 {
195 if (bpf_core_type_exists(struct trace_event_raw_kmem_alloc_node___x))
196 return true;
197 return false;
198 }
199
200 /**
201 * commit 2c1d697fb8ba("mm/slab_common: drop kmem_alloc & avoid dereferencing
202 * fields when not using") drops kmem_alloc event class. As a result,
203 * `trace_event_raw_kmem_alloc` is removed, `trace_event_raw_kmalloc` and
204 * `trace_event_raw_kmem_cache_alloc` are added.
205 * see:
206 * https://github.com/torvalds/linux/commit/2c1d697fb8ba
207 */
208 struct trace_event_raw_kmem_alloc___x {
209 const void *ptr;
210 size_t bytes_alloc;
211 } __attribute__((preserve_access_index));
212
213 struct trace_event_raw_kmalloc___x {
214 const void *ptr;
215 size_t bytes_alloc;
216 } __attribute__((preserve_access_index));
217
218 struct trace_event_raw_kmem_cache_alloc___x {
219 const void *ptr;
220 size_t bytes_alloc;
221 } __attribute__((preserve_access_index));
222
has_kmem_alloc(void)223 static __always_inline bool has_kmem_alloc(void)
224 {
225 if (bpf_core_type_exists(struct trace_event_raw_kmem_alloc___x))
226 return true;
227 return false;
228 }
229
230 /**
231 * The bpf_get_socket_cookie helper is landed since kernel v4.12，
232 * but only available for tracing programs since kernel v5.12
233 * via commit c5dbb89fc2ac("bpf: Expose bpf_get_socket_cookie to tracing programs").
234 * Since the helper is used to provide a unique socket identifier,
235 * we could use the sock itself as the identifier if the helper is not available.
236 * Here, we use BPF_FUNC_check_mtu to check the availability of the helper
237 * since they are both introduced in v5.12.
238 *
239 * see:
240 * https://github.com/torvalds/linux/commit/91b8270f2a4d
241 * https://github.com/torvalds/linux/commit/c5dbb89fc2ac
242 * https://github.com/torvalds/linux/commit/34b2021cc616
243 */
get_sock_ident(struct sock * sk)244 static __always_inline __u64 get_sock_ident(struct sock *sk)
245 {
246 if (bpf_core_enum_value_exists(enum bpf_func_id, BPF_FUNC_check_mtu)) {
247 return bpf_get_socket_cookie(sk);
248 }
249 return (__u64)sk;
250 }
251
252 #endif /* __CORE_FIXES_BPF_H */
253