1 // SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
2
3 #ifndef _GNU_SOURCE
4 #define _GNU_SOURCE
5 #endif
6
7 #include <errno.h>
8 #include <stdlib.h>
9 #include <linux/err.h>
10 #include <linux/kernel.h>
11 #include <bpf/bpf.h>
12 #include "bpf-utils.h"
13 #include "debug.h"
14
15 struct bpil_array_desc {
16 int array_offset; /* e.g. offset of jited_prog_insns */
17 int count_offset; /* e.g. offset of jited_prog_len */
18 int size_offset; /* > 0: offset of rec size,
19 * < 0: fix size of -size_offset
20 */
21 };
22
23 static struct bpil_array_desc bpil_array_desc[] = {
24 [PERF_BPIL_JITED_INSNS] = {
25 offsetof(struct bpf_prog_info, jited_prog_insns),
26 offsetof(struct bpf_prog_info, jited_prog_len),
27 -1,
28 },
29 [PERF_BPIL_XLATED_INSNS] = {
30 offsetof(struct bpf_prog_info, xlated_prog_insns),
31 offsetof(struct bpf_prog_info, xlated_prog_len),
32 -1,
33 },
34 [PERF_BPIL_MAP_IDS] = {
35 offsetof(struct bpf_prog_info, map_ids),
36 offsetof(struct bpf_prog_info, nr_map_ids),
37 -(int)sizeof(__u32),
38 },
39 [PERF_BPIL_JITED_KSYMS] = {
40 offsetof(struct bpf_prog_info, jited_ksyms),
41 offsetof(struct bpf_prog_info, nr_jited_ksyms),
42 -(int)sizeof(__u64),
43 },
44 [PERF_BPIL_JITED_FUNC_LENS] = {
45 offsetof(struct bpf_prog_info, jited_func_lens),
46 offsetof(struct bpf_prog_info, nr_jited_func_lens),
47 -(int)sizeof(__u32),
48 },
49 [PERF_BPIL_FUNC_INFO] = {
50 offsetof(struct bpf_prog_info, func_info),
51 offsetof(struct bpf_prog_info, nr_func_info),
52 offsetof(struct bpf_prog_info, func_info_rec_size),
53 },
54 [PERF_BPIL_LINE_INFO] = {
55 offsetof(struct bpf_prog_info, line_info),
56 offsetof(struct bpf_prog_info, nr_line_info),
57 offsetof(struct bpf_prog_info, line_info_rec_size),
58 },
59 [PERF_BPIL_JITED_LINE_INFO] = {
60 offsetof(struct bpf_prog_info, jited_line_info),
61 offsetof(struct bpf_prog_info, nr_jited_line_info),
62 offsetof(struct bpf_prog_info, jited_line_info_rec_size),
63 },
64 [PERF_BPIL_PROG_TAGS] = {
65 offsetof(struct bpf_prog_info, prog_tags),
66 offsetof(struct bpf_prog_info, nr_prog_tags),
67 -(int)sizeof(__u8) * BPF_TAG_SIZE,
68 },
69
70 };
71
bpf_prog_info_read_offset_u32(struct bpf_prog_info * info,int offset)72 static __u32 bpf_prog_info_read_offset_u32(struct bpf_prog_info *info,
73 int offset)
74 {
75 __u32 *array = (__u32 *)info;
76
77 if (offset >= 0)
78 return array[offset / sizeof(__u32)];
79 return -(int)offset;
80 }
81
bpf_prog_info_read_offset_u64(struct bpf_prog_info * info,int offset)82 static __u64 bpf_prog_info_read_offset_u64(struct bpf_prog_info *info,
83 int offset)
84 {
85 __u64 *array = (__u64 *)info;
86
87 if (offset >= 0)
88 return array[offset / sizeof(__u64)];
89 return -(int)offset;
90 }
91
bpf_prog_info_set_offset_u32(struct bpf_prog_info * info,int offset,__u32 val)92 static void bpf_prog_info_set_offset_u32(struct bpf_prog_info *info, int offset,
93 __u32 val)
94 {
95 __u32 *array = (__u32 *)info;
96
97 if (offset >= 0)
98 array[offset / sizeof(__u32)] = val;
99 }
100
bpf_prog_info_set_offset_u64(struct bpf_prog_info * info,int offset,__u64 val)101 static void bpf_prog_info_set_offset_u64(struct bpf_prog_info *info, int offset,
102 __u64 val)
103 {
104 __u64 *array = (__u64 *)info;
105
106 if (offset >= 0)
107 array[offset / sizeof(__u64)] = val;
108 }
109
110 struct perf_bpil *
get_bpf_prog_info_linear(int fd,__u64 arrays)111 get_bpf_prog_info_linear(int fd, __u64 arrays)
112 {
113 struct bpf_prog_info info = {};
114 struct perf_bpil *info_linear;
115 __u32 info_len = sizeof(info);
116 __u32 data_len = 0;
117 int i, err;
118 void *ptr;
119
120 if (arrays >> PERF_BPIL_LAST_ARRAY)
121 return ERR_PTR(-EINVAL);
122
123 /* step 1: get array dimensions */
124 err = bpf_obj_get_info_by_fd(fd, &info, &info_len);
125 if (err) {
126 pr_debug("can't get prog info: %s", strerror(errno));
127 return ERR_PTR(-EFAULT);
128 }
129
130 /* step 2: calculate total size of all arrays */
131 for (i = PERF_BPIL_FIRST_ARRAY; i < PERF_BPIL_LAST_ARRAY; ++i) {
132 bool include_array = (arrays & (1UL << i)) > 0;
133 struct bpil_array_desc *desc;
134 __u32 count, size;
135
136 desc = bpil_array_desc + i;
137
138 /* kernel is too old to support this field */
139 if (info_len < desc->array_offset + sizeof(__u32) ||
140 info_len < desc->count_offset + sizeof(__u32) ||
141 (desc->size_offset > 0 && info_len < (__u32)desc->size_offset))
142 include_array = false;
143
144 if (!include_array) {
145 arrays &= ~(1UL << i); /* clear the bit */
146 continue;
147 }
148
149 count = bpf_prog_info_read_offset_u32(&info, desc->count_offset);
150 size = bpf_prog_info_read_offset_u32(&info, desc->size_offset);
151
152 data_len += roundup(count * size, sizeof(__u64));
153 }
154
155 /* step 3: allocate continuous memory */
156 info_linear = malloc(sizeof(struct perf_bpil) + data_len);
157 if (!info_linear)
158 return ERR_PTR(-ENOMEM);
159
160 /* step 4: fill data to info_linear->info */
161 info_linear->arrays = arrays;
162 memset(&info_linear->info, 0, sizeof(info));
163 ptr = info_linear->data;
164
165 for (i = PERF_BPIL_FIRST_ARRAY; i < PERF_BPIL_LAST_ARRAY; ++i) {
166 struct bpil_array_desc *desc;
167 __u32 count, size;
168
169 if ((arrays & (1UL << i)) == 0)
170 continue;
171
172 desc = bpil_array_desc + i;
173 count = bpf_prog_info_read_offset_u32(&info, desc->count_offset);
174 size = bpf_prog_info_read_offset_u32(&info, desc->size_offset);
175 bpf_prog_info_set_offset_u32(&info_linear->info,
176 desc->count_offset, count);
177 bpf_prog_info_set_offset_u32(&info_linear->info,
178 desc->size_offset, size);
179 bpf_prog_info_set_offset_u64(&info_linear->info,
180 desc->array_offset,
181 ptr_to_u64(ptr));
182 ptr += roundup(count * size, sizeof(__u64));
183 }
184
185 /* step 5: call syscall again to get required arrays */
186 err = bpf_obj_get_info_by_fd(fd, &info_linear->info, &info_len);
187 if (err) {
188 pr_debug("can't get prog info: %s", strerror(errno));
189 free(info_linear);
190 return ERR_PTR(-EFAULT);
191 }
192
193 /* step 6: verify the data */
194 for (i = PERF_BPIL_FIRST_ARRAY; i < PERF_BPIL_LAST_ARRAY; ++i) {
195 struct bpil_array_desc *desc;
196 __u32 v1, v2;
197
198 if ((arrays & (1UL << i)) == 0)
199 continue;
200
201 desc = bpil_array_desc + i;
202 v1 = bpf_prog_info_read_offset_u32(&info, desc->count_offset);
203 v2 = bpf_prog_info_read_offset_u32(&info_linear->info,
204 desc->count_offset);
205 if (v1 != v2)
206 pr_warning("%s: mismatch in element count\n", __func__);
207
208 v1 = bpf_prog_info_read_offset_u32(&info, desc->size_offset);
209 v2 = bpf_prog_info_read_offset_u32(&info_linear->info,
210 desc->size_offset);
211 if (v1 != v2)
212 pr_warning("%s: mismatch in rec size\n", __func__);
213 }
214
215 /* step 7: update info_len and data_len */
216 info_linear->info_len = sizeof(struct bpf_prog_info);
217 info_linear->data_len = data_len;
218
219 return info_linear;
220 }
221
bpil_addr_to_offs(struct perf_bpil * info_linear)222 void bpil_addr_to_offs(struct perf_bpil *info_linear)
223 {
224 int i;
225
226 for (i = PERF_BPIL_FIRST_ARRAY; i < PERF_BPIL_LAST_ARRAY; ++i) {
227 struct bpil_array_desc *desc;
228 __u64 addr, offs;
229
230 if ((info_linear->arrays & (1UL << i)) == 0)
231 continue;
232
233 desc = bpil_array_desc + i;
234 addr = bpf_prog_info_read_offset_u64(&info_linear->info,
235 desc->array_offset);
236 offs = addr - ptr_to_u64(info_linear->data);
237 bpf_prog_info_set_offset_u64(&info_linear->info,
238 desc->array_offset, offs);
239 }
240 }
241
bpil_offs_to_addr(struct perf_bpil * info_linear)242 void bpil_offs_to_addr(struct perf_bpil *info_linear)
243 {
244 int i;
245
246 for (i = PERF_BPIL_FIRST_ARRAY; i < PERF_BPIL_LAST_ARRAY; ++i) {
247 struct bpil_array_desc *desc;
248 __u64 addr, offs;
249
250 if ((info_linear->arrays & (1UL << i)) == 0)
251 continue;
252
253 desc = bpil_array_desc + i;
254 offs = bpf_prog_info_read_offset_u64(&info_linear->info,
255 desc->array_offset);
256 addr = offs + ptr_to_u64(info_linear->data);
257 bpf_prog_info_set_offset_u64(&info_linear->info,
258 desc->array_offset, addr);
259 }
260 }
261