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Linux/kernel/kallsyms.c

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Diff markup

Differences between /kernel/kallsyms.c (Version linux-6.12-rc7) and /kernel/kallsyms.c (Version linux-5.7.19)


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

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