1 // SPDX-License-Identifier: GPL-2.0-only <<
2 /* 1 /*
3 * kallsyms.c: in-kernel printing of symbolic 2 * kallsyms.c: in-kernel printing of symbolic oopses and stack traces.
4 * 3 *
5 * Rewritten and vastly simplified by Rusty Ru 4 * Rewritten and vastly simplified by Rusty Russell for in-kernel
6 * module loader: 5 * module loader:
7 * Copyright 2002 Rusty Russell <rusty@rustc 6 * Copyright 2002 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation
8 * 7 *
9 * ChangeLog: 8 * ChangeLog:
10 * 9 *
11 * (25/Aug/2004) Paulo Marques <pmarques@grupo 10 * (25/Aug/2004) Paulo Marques <pmarques@grupopie.com>
12 * Changed the compression method from st 11 * Changed the compression method from stem compression to "table lookup"
13 * compression (see scripts/kallsyms.c fo 12 * compression (see scripts/kallsyms.c for a more complete description)
14 */ 13 */
15 #include <linux/kallsyms.h> 14 #include <linux/kallsyms.h>
>> 15 #include <linux/module.h>
16 #include <linux/init.h> 16 #include <linux/init.h>
17 #include <linux/seq_file.h> 17 #include <linux/seq_file.h>
18 #include <linux/fs.h> 18 #include <linux/fs.h>
19 #include <linux/kdb.h> 19 #include <linux/kdb.h>
20 #include <linux/err.h> 20 #include <linux/err.h>
21 #include <linux/proc_fs.h> 21 #include <linux/proc_fs.h>
22 #include <linux/sched.h> /* for cond_re 22 #include <linux/sched.h> /* for cond_resched */
>> 23 #include <linux/mm.h>
23 #include <linux/ctype.h> 24 #include <linux/ctype.h>
24 #include <linux/slab.h> 25 #include <linux/slab.h>
25 #include <linux/filter.h> 26 #include <linux/filter.h>
26 #include <linux/ftrace.h> <<
27 #include <linux/kprobes.h> <<
28 #include <linux/build_bug.h> <<
29 #include <linux/compiler.h> 27 #include <linux/compiler.h>
30 #include <linux/module.h> <<
31 #include <linux/kernel.h> <<
32 #include <linux/bsearch.h> <<
33 #include <linux/btf_ids.h> <<
34 28
35 #include "kallsyms_internal.h" !! 29 #include <asm/sections.h>
>> 30
>> 31 /*
>> 32 * These will be re-linked against their real values
>> 33 * during the second link stage.
>> 34 */
>> 35 extern const unsigned long kallsyms_addresses[] __weak;
>> 36 extern const int kallsyms_offsets[] __weak;
>> 37 extern const u8 kallsyms_names[] __weak;
>> 38
>> 39 /*
>> 40 * Tell the compiler that the count isn't in the small data section if the arch
>> 41 * has one (eg: FRV).
>> 42 */
>> 43 extern const unsigned long kallsyms_num_syms
>> 44 __attribute__((weak, section(".rodata")));
>> 45
>> 46 extern const unsigned long kallsyms_relative_base
>> 47 __attribute__((weak, section(".rodata")));
>> 48
>> 49 extern const u8 kallsyms_token_table[] __weak;
>> 50 extern const u16 kallsyms_token_index[] __weak;
>> 51
>> 52 extern const unsigned long kallsyms_markers[] __weak;
>> 53
>> 54 static inline int is_kernel_inittext(unsigned long addr)
>> 55 {
>> 56 if (addr >= (unsigned long)_sinittext
>> 57 && addr <= (unsigned long)_einittext)
>> 58 return 1;
>> 59 return 0;
>> 60 }
>> 61
>> 62 static inline int is_kernel_text(unsigned long addr)
>> 63 {
>> 64 if ((addr >= (unsigned long)_stext && addr <= (unsigned long)_etext) ||
>> 65 arch_is_kernel_text(addr))
>> 66 return 1;
>> 67 return in_gate_area_no_mm(addr);
>> 68 }
>> 69
>> 70 static inline int is_kernel(unsigned long addr)
>> 71 {
>> 72 if (addr >= (unsigned long)_stext && addr <= (unsigned long)_end)
>> 73 return 1;
>> 74 return in_gate_area_no_mm(addr);
>> 75 }
>> 76
>> 77 static int is_ksym_addr(unsigned long addr)
>> 78 {
>> 79 if (IS_ENABLED(CONFIG_KALLSYMS_ALL))
>> 80 return is_kernel(addr);
>> 81
>> 82 return is_kernel_text(addr) || is_kernel_inittext(addr);
>> 83 }
36 84
37 /* 85 /*
38 * Expand a compressed symbol data into the re 86 * Expand a compressed symbol data into the resulting uncompressed string,
39 * if uncompressed string is too long (>= maxl 87 * if uncompressed string is too long (>= maxlen), it will be truncated,
40 * given the offset to where the symbol is in 88 * given the offset to where the symbol is in the compressed stream.
41 */ 89 */
42 static unsigned int kallsyms_expand_symbol(uns 90 static unsigned int kallsyms_expand_symbol(unsigned int off,
43 cha 91 char *result, size_t maxlen)
44 { 92 {
45 int len, skipped_first = 0; 93 int len, skipped_first = 0;
46 const char *tptr; !! 94 const u8 *tptr, *data;
47 const u8 *data; <<
48 95
49 /* Get the compressed symbol length fr 96 /* Get the compressed symbol length from the first symbol byte. */
50 data = &kallsyms_names[off]; 97 data = &kallsyms_names[off];
51 len = *data; 98 len = *data;
52 data++; 99 data++;
53 off++; <<
54 <<
55 /* If MSB is 1, it is a "big" symbol, <<
56 if ((len & 0x80) != 0) { <<
57 len = (len & 0x7F) | (*data << <<
58 data++; <<
59 off++; <<
60 } <<
61 100
62 /* 101 /*
63 * Update the offset to return the off 102 * Update the offset to return the offset for the next symbol on
64 * the compressed stream. 103 * the compressed stream.
65 */ 104 */
66 off += len; !! 105 off += len + 1;
67 106
68 /* 107 /*
69 * For every byte on the compressed sy 108 * For every byte on the compressed symbol data, copy the table
70 * entry for that byte. 109 * entry for that byte.
71 */ 110 */
72 while (len) { 111 while (len) {
73 tptr = &kallsyms_token_table[k 112 tptr = &kallsyms_token_table[kallsyms_token_index[*data]];
74 data++; 113 data++;
75 len--; 114 len--;
76 115
77 while (*tptr) { 116 while (*tptr) {
78 if (skipped_first) { 117 if (skipped_first) {
79 if (maxlen <= 118 if (maxlen <= 1)
80 goto t 119 goto tail;
81 *result = *tpt 120 *result = *tptr;
82 result++; 121 result++;
83 maxlen--; 122 maxlen--;
84 } else 123 } else
85 skipped_first 124 skipped_first = 1;
86 tptr++; 125 tptr++;
87 } 126 }
88 } 127 }
89 128
90 tail: 129 tail:
91 if (maxlen) 130 if (maxlen)
92 *result = '\0'; 131 *result = '\0';
93 132
94 /* Return to offset to the next symbol 133 /* Return to offset to the next symbol. */
95 return off; 134 return off;
96 } 135 }
97 136
98 /* 137 /*
99 * Get symbol type information. This is encode 138 * Get symbol type information. This is encoded as a single char at the
100 * beginning of the symbol name. 139 * beginning of the symbol name.
101 */ 140 */
102 static char kallsyms_get_symbol_type(unsigned 141 static char kallsyms_get_symbol_type(unsigned int off)
103 { 142 {
104 /* 143 /*
105 * Get just the first code, look it up 144 * Get just the first code, look it up in the token table,
106 * and return the first char from this 145 * and return the first char from this token.
107 */ 146 */
108 return kallsyms_token_table[kallsyms_t 147 return kallsyms_token_table[kallsyms_token_index[kallsyms_names[off + 1]]];
109 } 148 }
110 149
111 150
112 /* 151 /*
113 * Find the offset on the compressed stream gi 152 * Find the offset on the compressed stream given and index in the
114 * kallsyms array. 153 * kallsyms array.
115 */ 154 */
116 static unsigned int get_symbol_offset(unsigned 155 static unsigned int get_symbol_offset(unsigned long pos)
117 { 156 {
118 const u8 *name; 157 const u8 *name;
119 int i, len; !! 158 int i;
120 159
121 /* 160 /*
122 * Use the closest marker we have. We 161 * Use the closest marker we have. We have markers every 256 positions,
123 * so that should be close enough. 162 * so that should be close enough.
124 */ 163 */
125 name = &kallsyms_names[kallsyms_marker 164 name = &kallsyms_names[kallsyms_markers[pos >> 8]];
126 165
127 /* 166 /*
128 * Sequentially scan all the symbols u 167 * Sequentially scan all the symbols up to the point we're searching
129 * for. Every symbol is stored in a [< 168 * for. Every symbol is stored in a [<len>][<len> bytes of data] format,
130 * so we just need to add the len to t 169 * so we just need to add the len to the current pointer for every
131 * symbol we wish to skip. 170 * symbol we wish to skip.
132 */ 171 */
133 for (i = 0; i < (pos & 0xFF); i++) { !! 172 for (i = 0; i < (pos & 0xFF); i++)
134 len = *name; !! 173 name = name + (*name) + 1;
135 <<
136 /* <<
137 * If MSB is 1, it is a "big" <<
138 * the next byte (and skip it, <<
139 */ <<
140 if ((len & 0x80) != 0) <<
141 len = ((len & 0x7F) | <<
142 <<
143 name = name + len + 1; <<
144 } <<
145 174
146 return name - kallsyms_names; 175 return name - kallsyms_names;
147 } 176 }
148 177
149 unsigned long kallsyms_sym_address(int idx) !! 178 static unsigned long kallsyms_sym_address(int idx)
150 { 179 {
>> 180 if (!IS_ENABLED(CONFIG_KALLSYMS_BASE_RELATIVE))
>> 181 return kallsyms_addresses[idx];
>> 182
151 /* values are unsigned offsets if --ab 183 /* values are unsigned offsets if --absolute-percpu is not in effect */
152 if (!IS_ENABLED(CONFIG_KALLSYMS_ABSOLU 184 if (!IS_ENABLED(CONFIG_KALLSYMS_ABSOLUTE_PERCPU))
153 return kallsyms_relative_base 185 return kallsyms_relative_base + (u32)kallsyms_offsets[idx];
154 186
155 /* ...otherwise, positive offsets are 187 /* ...otherwise, positive offsets are absolute values */
156 if (kallsyms_offsets[idx] >= 0) 188 if (kallsyms_offsets[idx] >= 0)
157 return kallsyms_offsets[idx]; 189 return kallsyms_offsets[idx];
158 190
159 /* ...and negative offsets are relativ 191 /* ...and negative offsets are relative to kallsyms_relative_base - 1 */
160 return kallsyms_relative_base - 1 - ka 192 return kallsyms_relative_base - 1 - kallsyms_offsets[idx];
161 } 193 }
162 194
163 static unsigned int get_symbol_seq(int index) <<
164 { <<
165 unsigned int i, seq = 0; <<
166 <<
167 for (i = 0; i < 3; i++) <<
168 seq = (seq << 8) | kallsyms_se <<
169 <<
170 return seq; <<
171 } <<
172 <<
173 static int kallsyms_lookup_names(const char *n <<
174 unsigned int <<
175 unsigned int <<
176 { <<
177 int ret; <<
178 int low, mid, high; <<
179 unsigned int seq, off; <<
180 char namebuf[KSYM_NAME_LEN]; <<
181 <<
182 low = 0; <<
183 high = kallsyms_num_syms - 1; <<
184 <<
185 while (low <= high) { <<
186 mid = low + (high - low) / 2; <<
187 seq = get_symbol_seq(mid); <<
188 off = get_symbol_offset(seq); <<
189 kallsyms_expand_symbol(off, na <<
190 ret = strcmp(name, namebuf); <<
191 if (ret > 0) <<
192 low = mid + 1; <<
193 else if (ret < 0) <<
194 high = mid - 1; <<
195 else <<
196 break; <<
197 } <<
198 <<
199 if (low > high) <<
200 return -ESRCH; <<
201 <<
202 low = mid; <<
203 while (low) { <<
204 seq = get_symbol_seq(low - 1); <<
205 off = get_symbol_offset(seq); <<
206 kallsyms_expand_symbol(off, na <<
207 if (strcmp(name, namebuf)) <<
208 break; <<
209 low--; <<
210 } <<
211 *start = low; <<
212 <<
213 if (end) { <<
214 high = mid; <<
215 while (high < kallsyms_num_sym <<
216 seq = get_symbol_seq(h <<
217 off = get_symbol_offse <<
218 kallsyms_expand_symbol <<
219 if (strcmp(name, nameb <<
220 break; <<
221 high++; <<
222 } <<
223 *end = high; <<
224 } <<
225 <<
226 return 0; <<
227 } <<
228 <<
229 /* Lookup the address for this symbol. Returns 195 /* Lookup the address for this symbol. Returns 0 if not found. */
230 unsigned long kallsyms_lookup_name(const char 196 unsigned long kallsyms_lookup_name(const char *name)
231 { 197 {
232 int ret; !! 198 char namebuf[KSYM_NAME_LEN];
233 unsigned int i; !! 199 unsigned long i;
234 !! 200 unsigned int off;
235 /* Skip the search for empty string. * <<
236 if (!*name) <<
237 return 0; <<
238 201
239 ret = kallsyms_lookup_names(name, &i, !! 202 for (i = 0, off = 0; i < kallsyms_num_syms; i++) {
240 if (!ret) !! 203 off = kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf));
241 return kallsyms_sym_address(ge <<
242 204
>> 205 if (strcmp(namebuf, name) == 0)
>> 206 return kallsyms_sym_address(i);
>> 207 }
243 return module_kallsyms_lookup_name(nam 208 return module_kallsyms_lookup_name(name);
244 } 209 }
>> 210 EXPORT_SYMBOL_GPL(kallsyms_lookup_name);
245 211
246 /* !! 212 int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
247 * Iterate over all symbols in vmlinux. For s !! 213 unsigned long),
248 * module_kallsyms_on_each_symbol instead. <<
249 */ <<
250 int kallsyms_on_each_symbol(int (*fn)(void *, <<
251 void *data) 214 void *data)
252 { 215 {
253 char namebuf[KSYM_NAME_LEN]; 216 char namebuf[KSYM_NAME_LEN];
254 unsigned long i; 217 unsigned long i;
255 unsigned int off; 218 unsigned int off;
256 int ret; 219 int ret;
257 220
258 for (i = 0, off = 0; i < kallsyms_num_ 221 for (i = 0, off = 0; i < kallsyms_num_syms; i++) {
259 off = kallsyms_expand_symbol(o 222 off = kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf));
260 ret = fn(data, namebuf, kallsy !! 223 ret = fn(data, namebuf, NULL, kallsyms_sym_address(i));
261 if (ret != 0) 224 if (ret != 0)
262 return ret; 225 return ret;
263 cond_resched(); <<
264 } 226 }
265 return 0; !! 227 return module_kallsyms_on_each_symbol(fn, data);
266 } <<
267 <<
268 int kallsyms_on_each_match_symbol(int (*fn)(vo <<
269 const char * <<
270 { <<
271 int ret; <<
272 unsigned int i, start, end; <<
273 <<
274 ret = kallsyms_lookup_names(name, &sta <<
275 if (ret) <<
276 return 0; <<
277 <<
278 for (i = start; !ret && i <= end; i++) <<
279 ret = fn(data, kallsyms_sym_ad <<
280 cond_resched(); <<
281 } <<
282 <<
283 return ret; <<
284 } 228 }
>> 229 EXPORT_SYMBOL_GPL(kallsyms_on_each_symbol);
285 230
286 static unsigned long get_symbol_pos(unsigned l 231 static unsigned long get_symbol_pos(unsigned long addr,
287 unsigned l 232 unsigned long *symbolsize,
288 unsigned l 233 unsigned long *offset)
289 { 234 {
290 unsigned long symbol_start = 0, symbol 235 unsigned long symbol_start = 0, symbol_end = 0;
291 unsigned long i, low, high, mid; 236 unsigned long i, low, high, mid;
292 237
293 /* Do a binary search on the sorted ka !! 238 /* This kernel should never had been booted. */
>> 239 if (!IS_ENABLED(CONFIG_KALLSYMS_BASE_RELATIVE))
>> 240 BUG_ON(!kallsyms_addresses);
>> 241 else
>> 242 BUG_ON(!kallsyms_offsets);
>> 243
>> 244 /* Do a binary search on the sorted kallsyms_addresses array. */
294 low = 0; 245 low = 0;
295 high = kallsyms_num_syms; 246 high = kallsyms_num_syms;
296 247
297 while (high - low > 1) { 248 while (high - low > 1) {
298 mid = low + (high - low) / 2; 249 mid = low + (high - low) / 2;
299 if (kallsyms_sym_address(mid) 250 if (kallsyms_sym_address(mid) <= addr)
300 low = mid; 251 low = mid;
301 else 252 else
302 high = mid; 253 high = mid;
303 } 254 }
304 255
305 /* 256 /*
306 * Search for the first aliased symbol 257 * Search for the first aliased symbol. Aliased
307 * symbols are symbols with the same a 258 * symbols are symbols with the same address.
308 */ 259 */
309 while (low && kallsyms_sym_address(low 260 while (low && kallsyms_sym_address(low-1) == kallsyms_sym_address(low))
310 --low; 261 --low;
311 262
312 symbol_start = kallsyms_sym_address(lo 263 symbol_start = kallsyms_sym_address(low);
313 264
314 /* Search for next non-aliased symbol. 265 /* Search for next non-aliased symbol. */
315 for (i = low + 1; i < kallsyms_num_sym 266 for (i = low + 1; i < kallsyms_num_syms; i++) {
316 if (kallsyms_sym_address(i) > 267 if (kallsyms_sym_address(i) > symbol_start) {
317 symbol_end = kallsyms_ 268 symbol_end = kallsyms_sym_address(i);
318 break; 269 break;
319 } 270 }
320 } 271 }
321 272
322 /* If we found no next symbol, we use 273 /* If we found no next symbol, we use the end of the section. */
323 if (!symbol_end) { 274 if (!symbol_end) {
324 if (is_kernel_inittext(addr)) 275 if (is_kernel_inittext(addr))
325 symbol_end = (unsigned 276 symbol_end = (unsigned long)_einittext;
326 else if (IS_ENABLED(CONFIG_KAL 277 else if (IS_ENABLED(CONFIG_KALLSYMS_ALL))
327 symbol_end = (unsigned 278 symbol_end = (unsigned long)_end;
328 else 279 else
329 symbol_end = (unsigned 280 symbol_end = (unsigned long)_etext;
330 } 281 }
331 282
332 if (symbolsize) 283 if (symbolsize)
333 *symbolsize = symbol_end - sym 284 *symbolsize = symbol_end - symbol_start;
334 if (offset) 285 if (offset)
335 *offset = addr - symbol_start; 286 *offset = addr - symbol_start;
336 287
337 return low; 288 return low;
338 } 289 }
339 290
340 /* 291 /*
341 * Lookup an address but don't bother to find 292 * Lookup an address but don't bother to find any names.
342 */ 293 */
343 int kallsyms_lookup_size_offset(unsigned long 294 int kallsyms_lookup_size_offset(unsigned long addr, unsigned long *symbolsize,
344 unsigned long 295 unsigned long *offset)
345 { 296 {
346 char namebuf[KSYM_NAME_LEN]; 297 char namebuf[KSYM_NAME_LEN];
347 298
348 if (is_ksym_addr(addr)) { !! 299 if (is_ksym_addr(addr))
349 get_symbol_pos(addr, symbolsiz !! 300 return !!get_symbol_pos(addr, symbolsize, offset);
350 return 1; !! 301 return !!module_address_lookup(addr, symbolsize, offset, NULL, namebuf) ||
351 } <<
352 return !!module_address_lookup(addr, s <<
353 !!__bpf_address_lookup(addr, sy 302 !!__bpf_address_lookup(addr, symbolsize, offset, namebuf);
354 } 303 }
355 304
356 static int kallsyms_lookup_buildid(unsigned lo !! 305 /*
357 unsigned long *symbols !! 306 * Lookup an address
358 unsigned long *offset, !! 307 * - modname is set to NULL if it's in the kernel.
359 const unsigned char ** !! 308 * - We guarantee that the returned name is valid until we reschedule even if.
>> 309 * It resides in a module.
>> 310 * - We also guarantee that modname will be valid until rescheduled.
>> 311 */
>> 312 const char *kallsyms_lookup(unsigned long addr,
>> 313 unsigned long *symbolsize,
>> 314 unsigned long *offset,
>> 315 char **modname, char *namebuf)
360 { 316 {
361 int ret; !! 317 const char *ret;
362 318
363 namebuf[KSYM_NAME_LEN - 1] = 0; 319 namebuf[KSYM_NAME_LEN - 1] = 0;
364 namebuf[0] = 0; 320 namebuf[0] = 0;
365 321
366 if (is_ksym_addr(addr)) { 322 if (is_ksym_addr(addr)) {
367 unsigned long pos; 323 unsigned long pos;
368 324
369 pos = get_symbol_pos(addr, sym 325 pos = get_symbol_pos(addr, symbolsize, offset);
370 /* Grab name */ 326 /* Grab name */
371 kallsyms_expand_symbol(get_sym 327 kallsyms_expand_symbol(get_symbol_offset(pos),
372 namebuf 328 namebuf, KSYM_NAME_LEN);
373 if (modname) 329 if (modname)
374 *modname = NULL; 330 *modname = NULL;
375 if (modbuildid) !! 331 return namebuf;
376 *modbuildid = NULL; <<
377 <<
378 return strlen(namebuf); <<
379 } 332 }
380 333
381 /* See if it's in a module or a BPF JI 334 /* See if it's in a module or a BPF JITed image. */
382 ret = module_address_lookup(addr, symb 335 ret = module_address_lookup(addr, symbolsize, offset,
383 modname, m !! 336 modname, namebuf);
384 if (!ret) 337 if (!ret)
385 ret = bpf_address_lookup(addr, 338 ret = bpf_address_lookup(addr, symbolsize,
386 offse 339 offset, modname, namebuf);
387 <<
388 if (!ret) <<
389 ret = ftrace_mod_address_looku <<
390 <<
391 <<
392 return ret; 340 return ret;
393 } 341 }
394 342
395 /* <<
396 * Lookup an address <<
397 * - modname is set to NULL if it's in the ker <<
398 * - We guarantee that the returned name is va <<
399 * It resides in a module. <<
400 * - We also guarantee that modname will be va <<
401 */ <<
402 const char *kallsyms_lookup(unsigned long addr <<
403 unsigned long *sym <<
404 unsigned long *off <<
405 char **modname, ch <<
406 { <<
407 int ret = kallsyms_lookup_buildid(addr <<
408 NULL <<
409 <<
410 if (!ret) <<
411 return NULL; <<
412 <<
413 return namebuf; <<
414 } <<
415 <<
416 int lookup_symbol_name(unsigned long addr, cha 343 int lookup_symbol_name(unsigned long addr, char *symname)
417 { 344 {
418 symname[0] = '\0'; 345 symname[0] = '\0';
419 symname[KSYM_NAME_LEN - 1] = '\0'; 346 symname[KSYM_NAME_LEN - 1] = '\0';
420 347
421 if (is_ksym_addr(addr)) { 348 if (is_ksym_addr(addr)) {
422 unsigned long pos; 349 unsigned long pos;
423 350
424 pos = get_symbol_pos(addr, NUL 351 pos = get_symbol_pos(addr, NULL, NULL);
425 /* Grab name */ 352 /* Grab name */
426 kallsyms_expand_symbol(get_sym 353 kallsyms_expand_symbol(get_symbol_offset(pos),
427 symname 354 symname, KSYM_NAME_LEN);
428 return 0; 355 return 0;
429 } 356 }
430 /* See if it's in a module. */ 357 /* See if it's in a module. */
431 return lookup_module_symbol_name(addr, 358 return lookup_module_symbol_name(addr, symname);
432 } 359 }
433 360
>> 361 int lookup_symbol_attrs(unsigned long addr, unsigned long *size,
>> 362 unsigned long *offset, char *modname, char *name)
>> 363 {
>> 364 name[0] = '\0';
>> 365 name[KSYM_NAME_LEN - 1] = '\0';
>> 366
>> 367 if (is_ksym_addr(addr)) {
>> 368 unsigned long pos;
>> 369
>> 370 pos = get_symbol_pos(addr, size, offset);
>> 371 /* Grab name */
>> 372 kallsyms_expand_symbol(get_symbol_offset(pos),
>> 373 name, KSYM_NAME_LEN);
>> 374 modname[0] = '\0';
>> 375 return 0;
>> 376 }
>> 377 /* See if it's in a module. */
>> 378 return lookup_module_symbol_attrs(addr, size, offset, modname, name);
>> 379 }
>> 380
434 /* Look up a kernel symbol and return it in a 381 /* Look up a kernel symbol and return it in a text buffer. */
435 static int __sprint_symbol(char *buffer, unsig 382 static int __sprint_symbol(char *buffer, unsigned long address,
436 int symbol_offset, !! 383 int symbol_offset, int add_offset)
437 { 384 {
438 char *modname; 385 char *modname;
439 const unsigned char *buildid; !! 386 const char *name;
440 unsigned long offset, size; 387 unsigned long offset, size;
441 int len; 388 int len;
442 389
443 address += symbol_offset; 390 address += symbol_offset;
444 len = kallsyms_lookup_buildid(address, !! 391 name = kallsyms_lookup(address, &size, &offset, &modname, buffer);
445 buffer) !! 392 if (!name)
446 if (!len) <<
447 return sprintf(buffer, "0x%lx" 393 return sprintf(buffer, "0x%lx", address - symbol_offset);
448 394
>> 395 if (name != buffer)
>> 396 strcpy(buffer, name);
>> 397 len = strlen(buffer);
449 offset -= symbol_offset; 398 offset -= symbol_offset;
450 399
451 if (add_offset) 400 if (add_offset)
452 len += sprintf(buffer + len, " 401 len += sprintf(buffer + len, "+%#lx/%#lx", offset, size);
453 402
454 if (modname) { !! 403 if (modname)
455 len += sprintf(buffer + len, " !! 404 len += sprintf(buffer + len, " [%s]", modname);
456 #if IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID) <<
457 if (add_buildid && buildid) { <<
458 /* build ID should mat <<
459 #if IS_ENABLED(CONFIG_MODULES) <<
460 static_assert(sizeof(t <<
461 #endif <<
462 len += sprintf(buffer <<
463 } <<
464 #endif <<
465 len += sprintf(buffer + len, " <<
466 } <<
467 405
468 return len; 406 return len;
469 } 407 }
470 408
471 /** 409 /**
472 * sprint_symbol - Look up a kernel symbol and 410 * sprint_symbol - Look up a kernel symbol and return it in a text buffer
473 * @buffer: buffer to be stored 411 * @buffer: buffer to be stored
474 * @address: address to lookup 412 * @address: address to lookup
475 * 413 *
476 * This function looks up a kernel symbol with 414 * This function looks up a kernel symbol with @address and stores its name,
477 * offset, size and module name to @buffer if 415 * offset, size and module name to @buffer if possible. If no symbol was found,
478 * just saves its @address as is. 416 * just saves its @address as is.
479 * 417 *
480 * This function returns the number of bytes s 418 * This function returns the number of bytes stored in @buffer.
481 */ 419 */
482 int sprint_symbol(char *buffer, unsigned long 420 int sprint_symbol(char *buffer, unsigned long address)
483 { 421 {
484 return __sprint_symbol(buffer, address !! 422 return __sprint_symbol(buffer, address, 0, 1);
485 } 423 }
486 EXPORT_SYMBOL_GPL(sprint_symbol); 424 EXPORT_SYMBOL_GPL(sprint_symbol);
487 425
488 /** 426 /**
489 * sprint_symbol_build_id - Look up a kernel s <<
490 * @buffer: buffer to be stored <<
491 * @address: address to lookup <<
492 * <<
493 * This function looks up a kernel symbol with <<
494 * offset, size, module name and module build <<
495 * symbol was found, just saves its @address a <<
496 * <<
497 * This function returns the number of bytes s <<
498 */ <<
499 int sprint_symbol_build_id(char *buffer, unsig <<
500 { <<
501 return __sprint_symbol(buffer, address <<
502 } <<
503 EXPORT_SYMBOL_GPL(sprint_symbol_build_id); <<
504 <<
505 /** <<
506 * sprint_symbol_no_offset - Look up a kernel 427 * sprint_symbol_no_offset - Look up a kernel symbol and return it in a text buffer
507 * @buffer: buffer to be stored 428 * @buffer: buffer to be stored
508 * @address: address to lookup 429 * @address: address to lookup
509 * 430 *
510 * This function looks up a kernel symbol with 431 * This function looks up a kernel symbol with @address and stores its name
511 * and module name to @buffer if possible. If 432 * and module name to @buffer if possible. If no symbol was found, just saves
512 * its @address as is. 433 * its @address as is.
513 * 434 *
514 * This function returns the number of bytes s 435 * This function returns the number of bytes stored in @buffer.
515 */ 436 */
516 int sprint_symbol_no_offset(char *buffer, unsi 437 int sprint_symbol_no_offset(char *buffer, unsigned long address)
517 { 438 {
518 return __sprint_symbol(buffer, address !! 439 return __sprint_symbol(buffer, address, 0, 0);
519 } 440 }
520 EXPORT_SYMBOL_GPL(sprint_symbol_no_offset); 441 EXPORT_SYMBOL_GPL(sprint_symbol_no_offset);
521 442
522 /** 443 /**
523 * sprint_backtrace - Look up a backtrace symb 444 * sprint_backtrace - Look up a backtrace symbol and return it in a text buffer
524 * @buffer: buffer to be stored 445 * @buffer: buffer to be stored
525 * @address: address to lookup 446 * @address: address to lookup
526 * 447 *
527 * This function is for stack backtrace and do 448 * This function is for stack backtrace and does the same thing as
528 * sprint_symbol() but with modified/decreased 449 * sprint_symbol() but with modified/decreased @address. If there is a
529 * tail-call to the function marked "noreturn" 450 * tail-call to the function marked "noreturn", gcc optimized out code after
530 * the call so that the stack-saved return add 451 * the call so that the stack-saved return address could point outside of the
531 * caller. This function ensures that kallsyms 452 * caller. This function ensures that kallsyms will find the original caller
532 * by decreasing @address. 453 * by decreasing @address.
533 * 454 *
534 * This function returns the number of bytes s 455 * This function returns the number of bytes stored in @buffer.
535 */ 456 */
536 int sprint_backtrace(char *buffer, unsigned lo 457 int sprint_backtrace(char *buffer, unsigned long address)
537 { 458 {
538 return __sprint_symbol(buffer, address !! 459 return __sprint_symbol(buffer, address, -1, 1);
539 } 460 }
540 461
541 /** !! 462 /* Look up a kernel symbol and print it to the kernel messages. */
542 * sprint_backtrace_build_id - Look up a backt !! 463 void __print_symbol(const char *fmt, unsigned long address)
543 * @buffer: buffer to be stored <<
544 * @address: address to lookup <<
545 * <<
546 * This function is for stack backtrace and do <<
547 * sprint_symbol() but with modified/decreased <<
548 * tail-call to the function marked "noreturn" <<
549 * the call so that the stack-saved return add <<
550 * caller. This function ensures that kallsyms <<
551 * by decreasing @address. This function also <<
552 * the @buffer if @address is within a kernel <<
553 * <<
554 * This function returns the number of bytes s <<
555 */ <<
556 int sprint_backtrace_build_id(char *buffer, un <<
557 { 464 {
558 return __sprint_symbol(buffer, address !! 465 char buffer[KSYM_SYMBOL_LEN];
>> 466
>> 467 sprint_symbol(buffer, address);
>> 468
>> 469 printk(fmt, buffer);
559 } 470 }
>> 471 EXPORT_SYMBOL(__print_symbol);
560 472
561 /* To avoid using get_symbol_offset for every 473 /* To avoid using get_symbol_offset for every symbol, we carry prefix along. */
562 struct kallsym_iter { 474 struct kallsym_iter {
563 loff_t pos; 475 loff_t pos;
564 loff_t pos_mod_end; 476 loff_t pos_mod_end;
565 loff_t pos_ftrace_mod_end; <<
566 loff_t pos_bpf_end; <<
567 unsigned long value; 477 unsigned long value;
568 unsigned int nameoff; /* If iterating 478 unsigned int nameoff; /* If iterating in core kernel symbols. */
569 char type; 479 char type;
570 char name[KSYM_NAME_LEN]; 480 char name[KSYM_NAME_LEN];
571 char module_name[MODULE_NAME_LEN]; 481 char module_name[MODULE_NAME_LEN];
572 int exported; 482 int exported;
573 int show_value; <<
574 }; 483 };
575 484
576 static int get_ksymbol_mod(struct kallsym_iter 485 static int get_ksymbol_mod(struct kallsym_iter *iter)
577 { 486 {
578 int ret = module_get_kallsym(iter->pos 487 int ret = module_get_kallsym(iter->pos - kallsyms_num_syms,
579 &iter->va 488 &iter->value, &iter->type,
580 iter->nam 489 iter->name, iter->module_name,
581 &iter->ex 490 &iter->exported);
582 if (ret < 0) { 491 if (ret < 0) {
583 iter->pos_mod_end = iter->pos; 492 iter->pos_mod_end = iter->pos;
584 return 0; 493 return 0;
585 } 494 }
586 495
587 return 1; 496 return 1;
588 } 497 }
589 498
590 /* <<
591 * ftrace_mod_get_kallsym() may also get symbo <<
592 * purposes. In that case "__builtin__ftrace" <<
593 * though "__builtin__ftrace" is not a module. <<
594 */ <<
595 static int get_ksymbol_ftrace_mod(struct kalls <<
596 { <<
597 int ret = ftrace_mod_get_kallsym(iter- <<
598 &iter <<
599 iter- <<
600 &iter <<
601 if (ret < 0) { <<
602 iter->pos_ftrace_mod_end = ite <<
603 return 0; <<
604 } <<
605 <<
606 return 1; <<
607 } <<
608 <<
609 static int get_ksymbol_bpf(struct kallsym_iter 499 static int get_ksymbol_bpf(struct kallsym_iter *iter)
610 { 500 {
611 int ret; !! 501 iter->module_name[0] = '\0';
612 <<
613 strscpy(iter->module_name, "bpf", MODU <<
614 iter->exported = 0; <<
615 ret = bpf_get_kallsym(iter->pos - iter <<
616 &iter->value, &i <<
617 iter->name); <<
618 if (ret < 0) { <<
619 iter->pos_bpf_end = iter->pos; <<
620 return 0; <<
621 } <<
622 <<
623 return 1; <<
624 } <<
625 <<
626 /* <<
627 * This uses "__builtin__kprobes" as a module <<
628 * allocated for kprobes' purposes, even thoug <<
629 * module. <<
630 */ <<
631 static int get_ksymbol_kprobe(struct kallsym_i <<
632 { <<
633 strscpy(iter->module_name, "__builtin_ <<
634 iter->exported = 0; 502 iter->exported = 0;
635 return kprobe_get_kallsym(iter->pos - !! 503 return bpf_get_kallsym(iter->pos - iter->pos_mod_end,
636 &iter->value !! 504 &iter->value, &iter->type,
637 iter->name) !! 505 iter->name) < 0 ? 0 : 1;
638 } 506 }
639 507
640 /* Returns space to next name. */ 508 /* Returns space to next name. */
641 static unsigned long get_ksymbol_core(struct k 509 static unsigned long get_ksymbol_core(struct kallsym_iter *iter)
642 { 510 {
643 unsigned off = iter->nameoff; 511 unsigned off = iter->nameoff;
644 512
645 iter->module_name[0] = '\0'; 513 iter->module_name[0] = '\0';
646 iter->value = kallsyms_sym_address(ite 514 iter->value = kallsyms_sym_address(iter->pos);
647 515
648 iter->type = kallsyms_get_symbol_type( 516 iter->type = kallsyms_get_symbol_type(off);
649 517
650 off = kallsyms_expand_symbol(off, iter 518 off = kallsyms_expand_symbol(off, iter->name, ARRAY_SIZE(iter->name));
651 519
652 return off - iter->nameoff; 520 return off - iter->nameoff;
653 } 521 }
654 522
655 static void reset_iter(struct kallsym_iter *it 523 static void reset_iter(struct kallsym_iter *iter, loff_t new_pos)
656 { 524 {
657 iter->name[0] = '\0'; 525 iter->name[0] = '\0';
658 iter->nameoff = get_symbol_offset(new_ 526 iter->nameoff = get_symbol_offset(new_pos);
659 iter->pos = new_pos; 527 iter->pos = new_pos;
660 if (new_pos == 0) { !! 528 if (new_pos == 0)
661 iter->pos_mod_end = 0; 529 iter->pos_mod_end = 0;
662 iter->pos_ftrace_mod_end = 0; <<
663 iter->pos_bpf_end = 0; <<
664 } <<
665 } 530 }
666 531
667 /* <<
668 * The end position (last + 1) of each additio <<
669 * in iter->pos_..._end as each section is add <<
670 * determine which get_ksymbol_...() function <<
671 */ <<
672 static int update_iter_mod(struct kallsym_iter 532 static int update_iter_mod(struct kallsym_iter *iter, loff_t pos)
673 { 533 {
674 iter->pos = pos; 534 iter->pos = pos;
675 535
676 if ((!iter->pos_mod_end || iter->pos_m !! 536 if (iter->pos_mod_end > 0 &&
677 get_ksymbol_mod(iter)) !! 537 iter->pos_mod_end < iter->pos)
678 return 1; !! 538 return get_ksymbol_bpf(iter);
679 <<
680 if ((!iter->pos_ftrace_mod_end || iter <<
681 get_ksymbol_ftrace_mod(iter)) <<
682 return 1; <<
683 539
684 if ((!iter->pos_bpf_end || iter->pos_b !! 540 if (!get_ksymbol_mod(iter))
685 get_ksymbol_bpf(iter)) !! 541 return get_ksymbol_bpf(iter);
686 return 1; <<
687 542
688 return get_ksymbol_kprobe(iter); !! 543 return 1;
689 } 544 }
690 545
691 /* Returns false if pos at or past end of file 546 /* Returns false if pos at or past end of file. */
692 static int update_iter(struct kallsym_iter *it 547 static int update_iter(struct kallsym_iter *iter, loff_t pos)
693 { 548 {
694 /* Module symbols can be accessed rand 549 /* Module symbols can be accessed randomly. */
695 if (pos >= kallsyms_num_syms) 550 if (pos >= kallsyms_num_syms)
696 return update_iter_mod(iter, p 551 return update_iter_mod(iter, pos);
697 552
698 /* If we're not on the desired positio 553 /* If we're not on the desired position, reset to new position. */
699 if (pos != iter->pos) 554 if (pos != iter->pos)
700 reset_iter(iter, pos); 555 reset_iter(iter, pos);
701 556
702 iter->nameoff += get_ksymbol_core(iter 557 iter->nameoff += get_ksymbol_core(iter);
703 iter->pos++; 558 iter->pos++;
704 559
705 return 1; 560 return 1;
706 } 561 }
707 562
708 static void *s_next(struct seq_file *m, void * 563 static void *s_next(struct seq_file *m, void *p, loff_t *pos)
709 { 564 {
710 (*pos)++; 565 (*pos)++;
711 566
712 if (!update_iter(m->private, *pos)) 567 if (!update_iter(m->private, *pos))
713 return NULL; 568 return NULL;
714 return p; 569 return p;
715 } 570 }
716 571
717 static void *s_start(struct seq_file *m, loff_ 572 static void *s_start(struct seq_file *m, loff_t *pos)
718 { 573 {
719 if (!update_iter(m->private, *pos)) 574 if (!update_iter(m->private, *pos))
720 return NULL; 575 return NULL;
721 return m->private; 576 return m->private;
722 } 577 }
723 578
724 static void s_stop(struct seq_file *m, void *p 579 static void s_stop(struct seq_file *m, void *p)
725 { 580 {
726 } 581 }
727 582
728 static int s_show(struct seq_file *m, void *p) 583 static int s_show(struct seq_file *m, void *p)
729 { 584 {
730 void *value; <<
731 struct kallsym_iter *iter = m->private 585 struct kallsym_iter *iter = m->private;
732 586
733 /* Some debugging symbols have no name 587 /* Some debugging symbols have no name. Ignore them. */
734 if (!iter->name[0]) 588 if (!iter->name[0])
735 return 0; 589 return 0;
736 590
737 value = iter->show_value ? (void *)ite <<
738 <<
739 if (iter->module_name[0]) { 591 if (iter->module_name[0]) {
740 char type; 592 char type;
741 593
742 /* 594 /*
743 * Label it "global" if it is 595 * Label it "global" if it is exported,
744 * "local" if not exported. 596 * "local" if not exported.
745 */ 597 */
746 type = iter->exported ? touppe 598 type = iter->exported ? toupper(iter->type) :
747 tolowe 599 tolower(iter->type);
748 seq_printf(m, "%px %c %s\t[%s] !! 600 seq_printf(m, "%pK %c %s\t[%s]\n", (void *)iter->value,
749 type, iter->name, i 601 type, iter->name, iter->module_name);
750 } else 602 } else
751 seq_printf(m, "%px %c %s\n", v !! 603 seq_printf(m, "%pK %c %s\n", (void *)iter->value,
752 iter->type, iter->n 604 iter->type, iter->name);
753 return 0; 605 return 0;
754 } 606 }
755 607
756 static const struct seq_operations kallsyms_op 608 static const struct seq_operations kallsyms_op = {
757 .start = s_start, 609 .start = s_start,
758 .next = s_next, 610 .next = s_next,
759 .stop = s_stop, 611 .stop = s_stop,
760 .show = s_show 612 .show = s_show
761 }; 613 };
762 614
763 #ifdef CONFIG_BPF_SYSCALL <<
764 <<
765 struct bpf_iter__ksym { <<
766 __bpf_md_ptr(struct bpf_iter_meta *, m <<
767 __bpf_md_ptr(struct kallsym_iter *, ks <<
768 }; <<
769 <<
770 static int ksym_prog_seq_show(struct seq_file <<
771 { <<
772 struct bpf_iter__ksym ctx; <<
773 struct bpf_iter_meta meta; <<
774 struct bpf_prog *prog; <<
775 <<
776 meta.seq = m; <<
777 prog = bpf_iter_get_info(&meta, in_sto <<
778 if (!prog) <<
779 return 0; <<
780 <<
781 ctx.meta = &meta; <<
782 ctx.ksym = m ? m->private : NULL; <<
783 return bpf_iter_run_prog(prog, &ctx); <<
784 } <<
785 <<
786 static int bpf_iter_ksym_seq_show(struct seq_f <<
787 { <<
788 return ksym_prog_seq_show(m, false); <<
789 } <<
790 <<
791 static void bpf_iter_ksym_seq_stop(struct seq_ <<
792 { <<
793 if (!p) <<
794 (void) ksym_prog_seq_show(m, t <<
795 else <<
796 s_stop(m, p); <<
797 } <<
798 <<
799 static const struct seq_operations bpf_iter_ks <<
800 .start = s_start, <<
801 .next = s_next, <<
802 .stop = bpf_iter_ksym_seq_stop, <<
803 .show = bpf_iter_ksym_seq_show, <<
804 }; <<
805 <<
806 static int bpf_iter_ksym_init(void *priv_data, <<
807 { <<
808 struct kallsym_iter *iter = priv_data; <<
809 <<
810 reset_iter(iter, 0); <<
811 <<
812 /* cache here as in kallsyms_open() ca <<
813 * credentials to tell BPF iterators i <<
814 */ <<
815 iter->show_value = kallsyms_show_value <<
816 <<
817 return 0; <<
818 } <<
819 <<
820 DEFINE_BPF_ITER_FUNC(ksym, struct bpf_iter_met <<
821 <<
822 static const struct bpf_iter_seq_info ksym_ite <<
823 .seq_ops = &bpf_iter_ks <<
824 .init_seq_private = bpf_iter_ksy <<
825 .fini_seq_private = NULL, <<
826 .seq_priv_size = sizeof(struc <<
827 }; <<
828 <<
829 static struct bpf_iter_reg ksym_iter_reg_info <<
830 .target = "ksym", <<
831 .feature = BPF_ITER_RES <<
832 .ctx_arg_info_size = 1, <<
833 .ctx_arg_info = { <<
834 { offsetof(struct bpf_iter__ks <<
835 PTR_TO_BTF_ID_OR_NULL }, <<
836 }, <<
837 .seq_info = &ksym_iter_s <<
838 }; <<
839 <<
840 BTF_ID_LIST(btf_ksym_iter_id) <<
841 BTF_ID(struct, kallsym_iter) <<
842 <<
843 static int __init bpf_ksym_iter_register(void) <<
844 { <<
845 ksym_iter_reg_info.ctx_arg_info[0].btf <<
846 return bpf_iter_reg_target(&ksym_iter_ <<
847 } <<
848 <<
849 late_initcall(bpf_ksym_iter_register); <<
850 <<
851 #endif /* CONFIG_BPF_SYSCALL */ <<
852 <<
853 static int kallsyms_open(struct inode *inode, 615 static int kallsyms_open(struct inode *inode, struct file *file)
854 { 616 {
855 /* 617 /*
856 * We keep iterator in m->private, sin 618 * We keep iterator in m->private, since normal case is to
857 * s_start from where we left off, so 619 * s_start from where we left off, so we avoid doing
858 * using get_symbol_offset for every s 620 * using get_symbol_offset for every symbol.
859 */ 621 */
860 struct kallsym_iter *iter; 622 struct kallsym_iter *iter;
861 iter = __seq_open_private(file, &kalls 623 iter = __seq_open_private(file, &kallsyms_op, sizeof(*iter));
862 if (!iter) 624 if (!iter)
863 return -ENOMEM; 625 return -ENOMEM;
864 reset_iter(iter, 0); 626 reset_iter(iter, 0);
865 627
866 /* <<
867 * Instead of checking this on every s <<
868 * the result here at open time. <<
869 */ <<
870 iter->show_value = kallsyms_show_value <<
871 return 0; 628 return 0;
872 } 629 }
873 630
874 #ifdef CONFIG_KGDB_KDB 631 #ifdef CONFIG_KGDB_KDB
875 const char *kdb_walk_kallsyms(loff_t *pos) 632 const char *kdb_walk_kallsyms(loff_t *pos)
876 { 633 {
877 static struct kallsym_iter kdb_walk_ka 634 static struct kallsym_iter kdb_walk_kallsyms_iter;
878 if (*pos == 0) { 635 if (*pos == 0) {
879 memset(&kdb_walk_kallsyms_iter 636 memset(&kdb_walk_kallsyms_iter, 0,
880 sizeof(kdb_walk_kallsym 637 sizeof(kdb_walk_kallsyms_iter));
881 reset_iter(&kdb_walk_kallsyms_ 638 reset_iter(&kdb_walk_kallsyms_iter, 0);
882 } 639 }
883 while (1) { 640 while (1) {
884 if (!update_iter(&kdb_walk_kal 641 if (!update_iter(&kdb_walk_kallsyms_iter, *pos))
885 return NULL; 642 return NULL;
886 ++*pos; 643 ++*pos;
887 /* Some debugging symbols have 644 /* Some debugging symbols have no name. Ignore them. */
888 if (kdb_walk_kallsyms_iter.nam 645 if (kdb_walk_kallsyms_iter.name[0])
889 return kdb_walk_kallsy 646 return kdb_walk_kallsyms_iter.name;
890 } 647 }
891 } 648 }
892 #endif /* CONFIG_KGDB_KDB */ 649 #endif /* CONFIG_KGDB_KDB */
893 650
894 static const struct proc_ops kallsyms_proc_ops !! 651 static const struct file_operations kallsyms_operations = {
895 .proc_open = kallsyms_open, !! 652 .open = kallsyms_open,
896 .proc_read = seq_read, !! 653 .read = seq_read,
897 .proc_lseek = seq_lseek, !! 654 .llseek = seq_lseek,
898 .proc_release = seq_release_private, !! 655 .release = seq_release_private,
899 }; 656 };
900 657
901 static int __init kallsyms_init(void) 658 static int __init kallsyms_init(void)
902 { 659 {
903 proc_create("kallsyms", 0444, NULL, &k !! 660 proc_create("kallsyms", 0444, NULL, &kallsyms_operations);
904 return 0; 661 return 0;
905 } 662 }
906 device_initcall(kallsyms_init); 663 device_initcall(kallsyms_init);
907 664
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