Thomas Gleixner | 457c899 | 2019-05-19 13:08:55 +0100 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0-only |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2 | /* |
| 3 | * kallsyms.c: in-kernel printing of symbolic oopses and stack traces. |
| 4 | * |
| 5 | * Rewritten and vastly simplified by Rusty Russell for in-kernel |
| 6 | * module loader: |
| 7 | * Copyright 2002 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation |
| 8 | * |
| 9 | * ChangeLog: |
| 10 | * |
| 11 | * (25/Aug/2004) Paulo Marques <pmarques@grupopie.com> |
| 12 | * Changed the compression method from stem compression to "table lookup" |
| 13 | * compression (see scripts/kallsyms.c for a more complete description) |
| 14 | */ |
| 15 | #include <linux/kallsyms.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 16 | #include <linux/init.h> |
| 17 | #include <linux/seq_file.h> |
| 18 | #include <linux/fs.h> |
Jason Wessel | 67fc4e0 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 19 | #include <linux/kdb.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 20 | #include <linux/err.h> |
| 21 | #include <linux/proc_fs.h> |
Tim Schmielau | 4e57b68 | 2005-10-30 15:03:48 -0800 | [diff] [blame] | 22 | #include <linux/sched.h> /* for cond_resched */ |
Adam B. Jerome | 07354a0 | 2006-12-06 20:35:30 -0800 | [diff] [blame] | 23 | #include <linux/ctype.h> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 24 | #include <linux/slab.h> |
Daniel Borkmann | 74451e66 | 2017-02-16 22:24:50 +0100 | [diff] [blame] | 25 | #include <linux/filter.h> |
Steven Rostedt (VMware) | aba4b5c | 2017-09-01 08:35:38 -0400 | [diff] [blame] | 26 | #include <linux/ftrace.h> |
Adrian Hunter | d002b8b | 2020-05-28 11:00:58 +0300 | [diff] [blame] | 27 | #include <linux/kprobes.h> |
Stephen Boyd | 9294523 | 2021-07-07 18:09:20 -0700 | [diff] [blame] | 28 | #include <linux/build_bug.h> |
Gideon Israel Dsouza | 52f5684c | 2014-04-07 15:39:20 -0700 | [diff] [blame] | 29 | #include <linux/compiler.h> |
Stephen Boyd | 9294523 | 2021-07-07 18:09:20 -0700 | [diff] [blame] | 30 | #include <linux/module.h> |
| 31 | #include <linux/kernel.h> |
Jiri Olsa | bed0d9a | 2022-05-10 14:26:13 +0200 | [diff] [blame] | 32 | #include <linux/bsearch.h> |
Alan Maguire | 647cafa | 2022-07-12 13:31:44 +0100 | [diff] [blame] | 33 | #include <linux/btf_ids.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 34 | |
Stephen Brennan | 71f8c15 | 2022-05-16 17:05:07 -0700 | [diff] [blame] | 35 | #include "kallsyms_internal.h" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 36 | |
Manish Katiyar | ad6ccfa | 2009-05-12 13:43:35 -0700 | [diff] [blame] | 37 | /* |
| 38 | * Expand a compressed symbol data into the resulting uncompressed string, |
Chen Gang | e3f2675 | 2013-04-15 15:04:43 +0930 | [diff] [blame] | 39 | * if uncompressed string is too long (>= maxlen), it will be truncated, |
Manish Katiyar | ad6ccfa | 2009-05-12 13:43:35 -0700 | [diff] [blame] | 40 | * given the offset to where the symbol is in the compressed stream. |
| 41 | */ |
Chen Gang | e3f2675 | 2013-04-15 15:04:43 +0930 | [diff] [blame] | 42 | static unsigned int kallsyms_expand_symbol(unsigned int off, |
| 43 | char *result, size_t maxlen) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 44 | { |
| 45 | int len, skipped_first = 0; |
Masahiro Yamada | cde26a6 | 2020-02-02 14:09:22 +0900 | [diff] [blame] | 46 | const char *tptr; |
| 47 | const u8 *data; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 48 | |
Manish Katiyar | ad6ccfa | 2009-05-12 13:43:35 -0700 | [diff] [blame] | 49 | /* Get the compressed symbol length from the first symbol byte. */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 50 | data = &kallsyms_names[off]; |
| 51 | len = *data; |
| 52 | data++; |
| 53 | |
Manish Katiyar | ad6ccfa | 2009-05-12 13:43:35 -0700 | [diff] [blame] | 54 | /* |
| 55 | * Update the offset to return the offset for the next symbol on |
| 56 | * the compressed stream. |
| 57 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 58 | off += len + 1; |
| 59 | |
Manish Katiyar | ad6ccfa | 2009-05-12 13:43:35 -0700 | [diff] [blame] | 60 | /* |
| 61 | * For every byte on the compressed symbol data, copy the table |
| 62 | * entry for that byte. |
| 63 | */ |
| 64 | while (len) { |
| 65 | tptr = &kallsyms_token_table[kallsyms_token_index[*data]]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 66 | data++; |
| 67 | len--; |
| 68 | |
| 69 | while (*tptr) { |
Manish Katiyar | ad6ccfa | 2009-05-12 13:43:35 -0700 | [diff] [blame] | 70 | if (skipped_first) { |
Chen Gang | e3f2675 | 2013-04-15 15:04:43 +0930 | [diff] [blame] | 71 | if (maxlen <= 1) |
| 72 | goto tail; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 73 | *result = *tptr; |
| 74 | result++; |
Chen Gang | e3f2675 | 2013-04-15 15:04:43 +0930 | [diff] [blame] | 75 | maxlen--; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 76 | } else |
| 77 | skipped_first = 1; |
| 78 | tptr++; |
| 79 | } |
| 80 | } |
| 81 | |
Chen Gang | e3f2675 | 2013-04-15 15:04:43 +0930 | [diff] [blame] | 82 | tail: |
| 83 | if (maxlen) |
| 84 | *result = '\0'; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 85 | |
Manish Katiyar | ad6ccfa | 2009-05-12 13:43:35 -0700 | [diff] [blame] | 86 | /* Return to offset to the next symbol. */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 87 | return off; |
| 88 | } |
| 89 | |
Manish Katiyar | ad6ccfa | 2009-05-12 13:43:35 -0700 | [diff] [blame] | 90 | /* |
| 91 | * Get symbol type information. This is encoded as a single char at the |
| 92 | * beginning of the symbol name. |
| 93 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 94 | static char kallsyms_get_symbol_type(unsigned int off) |
| 95 | { |
Manish Katiyar | ad6ccfa | 2009-05-12 13:43:35 -0700 | [diff] [blame] | 96 | /* |
| 97 | * Get just the first code, look it up in the token table, |
| 98 | * and return the first char from this token. |
| 99 | */ |
| 100 | return kallsyms_token_table[kallsyms_token_index[kallsyms_names[off + 1]]]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 101 | } |
| 102 | |
| 103 | |
Manish Katiyar | ad6ccfa | 2009-05-12 13:43:35 -0700 | [diff] [blame] | 104 | /* |
| 105 | * Find the offset on the compressed stream given and index in the |
| 106 | * kallsyms array. |
| 107 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 108 | static unsigned int get_symbol_offset(unsigned long pos) |
| 109 | { |
Jan Beulich | aad0947 | 2006-12-08 02:35:57 -0800 | [diff] [blame] | 110 | const u8 *name; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 111 | int i; |
| 112 | |
Manish Katiyar | ad6ccfa | 2009-05-12 13:43:35 -0700 | [diff] [blame] | 113 | /* |
| 114 | * Use the closest marker we have. We have markers every 256 positions, |
| 115 | * so that should be close enough. |
| 116 | */ |
| 117 | name = &kallsyms_names[kallsyms_markers[pos >> 8]]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 118 | |
Manish Katiyar | ad6ccfa | 2009-05-12 13:43:35 -0700 | [diff] [blame] | 119 | /* |
| 120 | * Sequentially scan all the symbols up to the point we're searching |
| 121 | * for. Every symbol is stored in a [<len>][<len> bytes of data] format, |
| 122 | * so we just need to add the len to the current pointer for every |
| 123 | * symbol we wish to skip. |
| 124 | */ |
| 125 | for (i = 0; i < (pos & 0xFF); i++) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 126 | name = name + (*name) + 1; |
| 127 | |
| 128 | return name - kallsyms_names; |
| 129 | } |
| 130 | |
Ard Biesheuvel | 2213e9a | 2016-03-15 14:58:19 -0700 | [diff] [blame] | 131 | static unsigned long kallsyms_sym_address(int idx) |
| 132 | { |
| 133 | if (!IS_ENABLED(CONFIG_KALLSYMS_BASE_RELATIVE)) |
| 134 | return kallsyms_addresses[idx]; |
| 135 | |
| 136 | /* values are unsigned offsets if --absolute-percpu is not in effect */ |
| 137 | if (!IS_ENABLED(CONFIG_KALLSYMS_ABSOLUTE_PERCPU)) |
| 138 | return kallsyms_relative_base + (u32)kallsyms_offsets[idx]; |
| 139 | |
| 140 | /* ...otherwise, positive offsets are absolute values */ |
| 141 | if (kallsyms_offsets[idx] >= 0) |
| 142 | return kallsyms_offsets[idx]; |
| 143 | |
| 144 | /* ...and negative offsets are relative to kallsyms_relative_base - 1 */ |
| 145 | return kallsyms_relative_base - 1 - kallsyms_offsets[idx]; |
| 146 | } |
| 147 | |
Nick Desaulniers | 6eb4bd9 | 2021-10-04 09:29:33 -0700 | [diff] [blame] | 148 | static bool cleanup_symbol_name(char *s) |
Sami Tolvanen | 8b8e6b5 | 2021-04-08 11:28:32 -0700 | [diff] [blame] | 149 | { |
| 150 | char *res; |
| 151 | |
Nick Desaulniers | 6eb4bd9 | 2021-10-04 09:29:33 -0700 | [diff] [blame] | 152 | if (!IS_ENABLED(CONFIG_LTO_CLANG)) |
| 153 | return false; |
Sami Tolvanen | 8b8e6b5 | 2021-04-08 11:28:32 -0700 | [diff] [blame] | 154 | |
Nick Desaulniers | 6eb4bd9 | 2021-10-04 09:29:33 -0700 | [diff] [blame] | 155 | /* |
| 156 | * LLVM appends various suffixes for local functions and variables that |
| 157 | * must be promoted to global scope as part of LTO. This can break |
| 158 | * hooking of static functions with kprobes. '.' is not a valid |
| 159 | * character in an identifier in C. Suffixes observed: |
| 160 | * - foo.llvm.[0-9a-f]+ |
| 161 | * - foo.[0-9a-f]+ |
| 162 | * - foo.[0-9a-f]+.cfi_jt |
| 163 | */ |
| 164 | res = strchr(s, '.'); |
| 165 | if (res) { |
| 166 | *res = '\0'; |
| 167 | return true; |
| 168 | } |
| 169 | |
| 170 | if (!IS_ENABLED(CONFIG_CFI_CLANG) || |
| 171 | !IS_ENABLED(CONFIG_LTO_CLANG_THIN) || |
| 172 | CONFIG_CLANG_VERSION >= 130000) |
| 173 | return false; |
| 174 | |
| 175 | /* |
| 176 | * Prior to LLVM 13, the following suffixes were observed when thinLTO |
| 177 | * and CFI are both enabled: |
| 178 | * - foo$[0-9]+ |
| 179 | */ |
| 180 | res = strrchr(s, '$'); |
| 181 | if (res) { |
| 182 | *res = '\0'; |
| 183 | return true; |
| 184 | } |
| 185 | |
| 186 | return false; |
Sami Tolvanen | 8b8e6b5 | 2021-04-08 11:28:32 -0700 | [diff] [blame] | 187 | } |
Sami Tolvanen | 8b8e6b5 | 2021-04-08 11:28:32 -0700 | [diff] [blame] | 188 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 189 | /* Lookup the address for this symbol. Returns 0 if not found. */ |
| 190 | unsigned long kallsyms_lookup_name(const char *name) |
| 191 | { |
Tejun Heo | 9281acea | 2007-07-17 04:03:51 -0700 | [diff] [blame] | 192 | char namebuf[KSYM_NAME_LEN]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 193 | unsigned long i; |
| 194 | unsigned int off; |
| 195 | |
Jiri Olsa | aecf489 | 2022-03-16 13:24:08 +0100 | [diff] [blame] | 196 | /* Skip the search for empty string. */ |
| 197 | if (!*name) |
| 198 | return 0; |
| 199 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 200 | for (i = 0, off = 0; i < kallsyms_num_syms; i++) { |
Chen Gang | e3f2675 | 2013-04-15 15:04:43 +0930 | [diff] [blame] | 201 | off = kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 202 | |
| 203 | if (strcmp(namebuf, name) == 0) |
Ard Biesheuvel | 2213e9a | 2016-03-15 14:58:19 -0700 | [diff] [blame] | 204 | return kallsyms_sym_address(i); |
Sami Tolvanen | 8b8e6b5 | 2021-04-08 11:28:32 -0700 | [diff] [blame] | 205 | |
| 206 | if (cleanup_symbol_name(namebuf) && strcmp(namebuf, name) == 0) |
| 207 | return kallsyms_sym_address(i); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 208 | } |
| 209 | return module_kallsyms_lookup_name(name); |
| 210 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 211 | |
Christoph Hellwig | 013c166 | 2021-02-02 13:13:26 +0100 | [diff] [blame] | 212 | /* |
| 213 | * Iterate over all symbols in vmlinux. For symbols from modules use |
| 214 | * module_kallsyms_on_each_symbol instead. |
| 215 | */ |
Anders Kaseorg | 75a6661 | 2008-12-05 19:03:58 -0500 | [diff] [blame] | 216 | int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *, |
| 217 | unsigned long), |
| 218 | void *data) |
| 219 | { |
| 220 | char namebuf[KSYM_NAME_LEN]; |
| 221 | unsigned long i; |
| 222 | unsigned int off; |
| 223 | int ret; |
| 224 | |
| 225 | for (i = 0, off = 0; i < kallsyms_num_syms; i++) { |
Chen Gang | e3f2675 | 2013-04-15 15:04:43 +0930 | [diff] [blame] | 226 | off = kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf)); |
Ard Biesheuvel | 2213e9a | 2016-03-15 14:58:19 -0700 | [diff] [blame] | 227 | ret = fn(data, namebuf, NULL, kallsyms_sym_address(i)); |
Anders Kaseorg | 75a6661 | 2008-12-05 19:03:58 -0500 | [diff] [blame] | 228 | if (ret != 0) |
| 229 | return ret; |
David Vernet | f5bdb34 | 2021-12-29 13:56:47 -0800 | [diff] [blame] | 230 | cond_resched(); |
Anders Kaseorg | 75a6661 | 2008-12-05 19:03:58 -0500 | [diff] [blame] | 231 | } |
Christoph Hellwig | 013c166 | 2021-02-02 13:13:26 +0100 | [diff] [blame] | 232 | return 0; |
Anders Kaseorg | 75a6661 | 2008-12-05 19:03:58 -0500 | [diff] [blame] | 233 | } |
Anders Kaseorg | 75a6661 | 2008-12-05 19:03:58 -0500 | [diff] [blame] | 234 | |
Franck Bui-Huu | ffc5089 | 2006-10-03 01:13:48 -0700 | [diff] [blame] | 235 | static unsigned long get_symbol_pos(unsigned long addr, |
| 236 | unsigned long *symbolsize, |
| 237 | unsigned long *offset) |
| 238 | { |
| 239 | unsigned long symbol_start = 0, symbol_end = 0; |
| 240 | unsigned long i, low, high, mid; |
| 241 | |
Sam Ravnborg | 2ea0389 | 2009-01-14 21:38:20 +0100 | [diff] [blame] | 242 | /* This kernel should never had been booted. */ |
Ard Biesheuvel | 2213e9a | 2016-03-15 14:58:19 -0700 | [diff] [blame] | 243 | if (!IS_ENABLED(CONFIG_KALLSYMS_BASE_RELATIVE)) |
| 244 | BUG_ON(!kallsyms_addresses); |
| 245 | else |
| 246 | BUG_ON(!kallsyms_offsets); |
Sam Ravnborg | 2ea0389 | 2009-01-14 21:38:20 +0100 | [diff] [blame] | 247 | |
Manish Katiyar | ad6ccfa | 2009-05-12 13:43:35 -0700 | [diff] [blame] | 248 | /* Do a binary search on the sorted kallsyms_addresses array. */ |
Franck Bui-Huu | ffc5089 | 2006-10-03 01:13:48 -0700 | [diff] [blame] | 249 | low = 0; |
| 250 | high = kallsyms_num_syms; |
| 251 | |
| 252 | while (high - low > 1) { |
Vegard Nossum | 2fc9c4e | 2008-07-25 01:45:34 -0700 | [diff] [blame] | 253 | mid = low + (high - low) / 2; |
Ard Biesheuvel | 2213e9a | 2016-03-15 14:58:19 -0700 | [diff] [blame] | 254 | if (kallsyms_sym_address(mid) <= addr) |
Franck Bui-Huu | ffc5089 | 2006-10-03 01:13:48 -0700 | [diff] [blame] | 255 | low = mid; |
| 256 | else |
| 257 | high = mid; |
| 258 | } |
| 259 | |
| 260 | /* |
Manish Katiyar | ad6ccfa | 2009-05-12 13:43:35 -0700 | [diff] [blame] | 261 | * Search for the first aliased symbol. Aliased |
| 262 | * symbols are symbols with the same address. |
Franck Bui-Huu | ffc5089 | 2006-10-03 01:13:48 -0700 | [diff] [blame] | 263 | */ |
Ard Biesheuvel | 2213e9a | 2016-03-15 14:58:19 -0700 | [diff] [blame] | 264 | while (low && kallsyms_sym_address(low-1) == kallsyms_sym_address(low)) |
Franck Bui-Huu | ffc5089 | 2006-10-03 01:13:48 -0700 | [diff] [blame] | 265 | --low; |
| 266 | |
Ard Biesheuvel | 2213e9a | 2016-03-15 14:58:19 -0700 | [diff] [blame] | 267 | symbol_start = kallsyms_sym_address(low); |
Franck Bui-Huu | ffc5089 | 2006-10-03 01:13:48 -0700 | [diff] [blame] | 268 | |
Manish Katiyar | ad6ccfa | 2009-05-12 13:43:35 -0700 | [diff] [blame] | 269 | /* Search for next non-aliased symbol. */ |
Franck Bui-Huu | ffc5089 | 2006-10-03 01:13:48 -0700 | [diff] [blame] | 270 | for (i = low + 1; i < kallsyms_num_syms; i++) { |
Ard Biesheuvel | 2213e9a | 2016-03-15 14:58:19 -0700 | [diff] [blame] | 271 | if (kallsyms_sym_address(i) > symbol_start) { |
| 272 | symbol_end = kallsyms_sym_address(i); |
Franck Bui-Huu | ffc5089 | 2006-10-03 01:13:48 -0700 | [diff] [blame] | 273 | break; |
| 274 | } |
| 275 | } |
| 276 | |
Manish Katiyar | ad6ccfa | 2009-05-12 13:43:35 -0700 | [diff] [blame] | 277 | /* If we found no next symbol, we use the end of the section. */ |
Franck Bui-Huu | ffc5089 | 2006-10-03 01:13:48 -0700 | [diff] [blame] | 278 | if (!symbol_end) { |
| 279 | if (is_kernel_inittext(addr)) |
| 280 | symbol_end = (unsigned long)_einittext; |
Masahiro Yamada | 63b23e2 | 2017-07-10 15:51:20 -0700 | [diff] [blame] | 281 | else if (IS_ENABLED(CONFIG_KALLSYMS_ALL)) |
Franck Bui-Huu | ffc5089 | 2006-10-03 01:13:48 -0700 | [diff] [blame] | 282 | symbol_end = (unsigned long)_end; |
| 283 | else |
| 284 | symbol_end = (unsigned long)_etext; |
| 285 | } |
| 286 | |
Alexey Dobriyan | ffb4512 | 2007-05-08 00:28:41 -0700 | [diff] [blame] | 287 | if (symbolsize) |
| 288 | *symbolsize = symbol_end - symbol_start; |
| 289 | if (offset) |
| 290 | *offset = addr - symbol_start; |
Franck Bui-Huu | ffc5089 | 2006-10-03 01:13:48 -0700 | [diff] [blame] | 291 | |
| 292 | return low; |
| 293 | } |
| 294 | |
| 295 | /* |
| 296 | * Lookup an address but don't bother to find any names. |
| 297 | */ |
| 298 | int kallsyms_lookup_size_offset(unsigned long addr, unsigned long *symbolsize, |
| 299 | unsigned long *offset) |
| 300 | { |
Rusty Russell | 6dd06c9 | 2008-01-29 17:13:22 -0500 | [diff] [blame] | 301 | char namebuf[KSYM_NAME_LEN]; |
Daniel Borkmann | 74451e66 | 2017-02-16 22:24:50 +0100 | [diff] [blame] | 302 | |
Marc Zyngier | 2a1a3fa | 2019-08-24 14:12:31 +0100 | [diff] [blame] | 303 | if (is_ksym_addr(addr)) { |
| 304 | get_symbol_pos(addr, symbolsize, offset); |
| 305 | return 1; |
| 306 | } |
Stephen Boyd | 9294523 | 2021-07-07 18:09:20 -0700 | [diff] [blame] | 307 | return !!module_address_lookup(addr, symbolsize, offset, NULL, NULL, namebuf) || |
Daniel Borkmann | 74451e66 | 2017-02-16 22:24:50 +0100 | [diff] [blame] | 308 | !!__bpf_address_lookup(addr, symbolsize, offset, namebuf); |
Franck Bui-Huu | ffc5089 | 2006-10-03 01:13:48 -0700 | [diff] [blame] | 309 | } |
| 310 | |
Stephen Boyd | 9294523 | 2021-07-07 18:09:20 -0700 | [diff] [blame] | 311 | static const char *kallsyms_lookup_buildid(unsigned long addr, |
| 312 | unsigned long *symbolsize, |
| 313 | unsigned long *offset, char **modname, |
| 314 | const unsigned char **modbuildid, char *namebuf) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 315 | { |
Daniel Borkmann | 74451e66 | 2017-02-16 22:24:50 +0100 | [diff] [blame] | 316 | const char *ret; |
| 317 | |
Tejun Heo | 9281acea | 2007-07-17 04:03:51 -0700 | [diff] [blame] | 318 | namebuf[KSYM_NAME_LEN - 1] = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 319 | namebuf[0] = 0; |
| 320 | |
Franck Bui-Huu | ffc5089 | 2006-10-03 01:13:48 -0700 | [diff] [blame] | 321 | if (is_ksym_addr(addr)) { |
| 322 | unsigned long pos; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 323 | |
Franck Bui-Huu | ffc5089 | 2006-10-03 01:13:48 -0700 | [diff] [blame] | 324 | pos = get_symbol_pos(addr, symbolsize, offset); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 325 | /* Grab name */ |
Chen Gang | e3f2675 | 2013-04-15 15:04:43 +0930 | [diff] [blame] | 326 | kallsyms_expand_symbol(get_symbol_offset(pos), |
| 327 | namebuf, KSYM_NAME_LEN); |
Kyle McMartin | 7a74fc4 | 2007-05-30 02:43:16 -0400 | [diff] [blame] | 328 | if (modname) |
| 329 | *modname = NULL; |
Stephen Boyd | 9294523 | 2021-07-07 18:09:20 -0700 | [diff] [blame] | 330 | if (modbuildid) |
| 331 | *modbuildid = NULL; |
Sami Tolvanen | 8b8e6b5 | 2021-04-08 11:28:32 -0700 | [diff] [blame] | 332 | |
| 333 | ret = namebuf; |
| 334 | goto found; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 335 | } |
| 336 | |
Daniel Borkmann | 74451e66 | 2017-02-16 22:24:50 +0100 | [diff] [blame] | 337 | /* See if it's in a module or a BPF JITed image. */ |
| 338 | ret = module_address_lookup(addr, symbolsize, offset, |
Stephen Boyd | 9294523 | 2021-07-07 18:09:20 -0700 | [diff] [blame] | 339 | modname, modbuildid, namebuf); |
Daniel Borkmann | 74451e66 | 2017-02-16 22:24:50 +0100 | [diff] [blame] | 340 | if (!ret) |
| 341 | ret = bpf_address_lookup(addr, symbolsize, |
| 342 | offset, modname, namebuf); |
Steven Rostedt (VMware) | aba4b5c | 2017-09-01 08:35:38 -0400 | [diff] [blame] | 343 | |
| 344 | if (!ret) |
| 345 | ret = ftrace_mod_address_lookup(addr, symbolsize, |
| 346 | offset, modname, namebuf); |
Sami Tolvanen | 8b8e6b5 | 2021-04-08 11:28:32 -0700 | [diff] [blame] | 347 | |
| 348 | found: |
| 349 | cleanup_symbol_name(namebuf); |
Daniel Borkmann | 74451e66 | 2017-02-16 22:24:50 +0100 | [diff] [blame] | 350 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 351 | } |
| 352 | |
Stephen Boyd | 9294523 | 2021-07-07 18:09:20 -0700 | [diff] [blame] | 353 | /* |
| 354 | * Lookup an address |
| 355 | * - modname is set to NULL if it's in the kernel. |
| 356 | * - We guarantee that the returned name is valid until we reschedule even if. |
| 357 | * It resides in a module. |
| 358 | * - We also guarantee that modname will be valid until rescheduled. |
| 359 | */ |
| 360 | const char *kallsyms_lookup(unsigned long addr, |
| 361 | unsigned long *symbolsize, |
| 362 | unsigned long *offset, |
| 363 | char **modname, char *namebuf) |
| 364 | { |
| 365 | return kallsyms_lookup_buildid(addr, symbolsize, offset, modname, |
| 366 | NULL, namebuf); |
| 367 | } |
| 368 | |
Alexey Dobriyan | 9d65cb4 | 2007-05-08 00:28:43 -0700 | [diff] [blame] | 369 | int lookup_symbol_name(unsigned long addr, char *symname) |
| 370 | { |
Sami Tolvanen | 8b8e6b5 | 2021-04-08 11:28:32 -0700 | [diff] [blame] | 371 | int res; |
| 372 | |
Alexey Dobriyan | 9d65cb4 | 2007-05-08 00:28:43 -0700 | [diff] [blame] | 373 | symname[0] = '\0'; |
Tejun Heo | 9281acea | 2007-07-17 04:03:51 -0700 | [diff] [blame] | 374 | symname[KSYM_NAME_LEN - 1] = '\0'; |
Alexey Dobriyan | 9d65cb4 | 2007-05-08 00:28:43 -0700 | [diff] [blame] | 375 | |
| 376 | if (is_ksym_addr(addr)) { |
| 377 | unsigned long pos; |
| 378 | |
| 379 | pos = get_symbol_pos(addr, NULL, NULL); |
| 380 | /* Grab name */ |
Chen Gang | e3f2675 | 2013-04-15 15:04:43 +0930 | [diff] [blame] | 381 | kallsyms_expand_symbol(get_symbol_offset(pos), |
| 382 | symname, KSYM_NAME_LEN); |
Sami Tolvanen | 8b8e6b5 | 2021-04-08 11:28:32 -0700 | [diff] [blame] | 383 | goto found; |
Alexey Dobriyan | 9d65cb4 | 2007-05-08 00:28:43 -0700 | [diff] [blame] | 384 | } |
Manish Katiyar | ad6ccfa | 2009-05-12 13:43:35 -0700 | [diff] [blame] | 385 | /* See if it's in a module. */ |
Sami Tolvanen | 8b8e6b5 | 2021-04-08 11:28:32 -0700 | [diff] [blame] | 386 | res = lookup_module_symbol_name(addr, symname); |
| 387 | if (res) |
| 388 | return res; |
| 389 | |
| 390 | found: |
| 391 | cleanup_symbol_name(symname); |
| 392 | return 0; |
Alexey Dobriyan | 9d65cb4 | 2007-05-08 00:28:43 -0700 | [diff] [blame] | 393 | } |
| 394 | |
Alexey Dobriyan | a5c43da | 2007-05-08 00:28:47 -0700 | [diff] [blame] | 395 | int lookup_symbol_attrs(unsigned long addr, unsigned long *size, |
| 396 | unsigned long *offset, char *modname, char *name) |
| 397 | { |
Sami Tolvanen | 8b8e6b5 | 2021-04-08 11:28:32 -0700 | [diff] [blame] | 398 | int res; |
| 399 | |
Alexey Dobriyan | a5c43da | 2007-05-08 00:28:47 -0700 | [diff] [blame] | 400 | name[0] = '\0'; |
Tejun Heo | 9281acea | 2007-07-17 04:03:51 -0700 | [diff] [blame] | 401 | name[KSYM_NAME_LEN - 1] = '\0'; |
Alexey Dobriyan | a5c43da | 2007-05-08 00:28:47 -0700 | [diff] [blame] | 402 | |
| 403 | if (is_ksym_addr(addr)) { |
| 404 | unsigned long pos; |
| 405 | |
| 406 | pos = get_symbol_pos(addr, size, offset); |
| 407 | /* Grab name */ |
Chen Gang | e3f2675 | 2013-04-15 15:04:43 +0930 | [diff] [blame] | 408 | kallsyms_expand_symbol(get_symbol_offset(pos), |
| 409 | name, KSYM_NAME_LEN); |
Alexey Dobriyan | a5c43da | 2007-05-08 00:28:47 -0700 | [diff] [blame] | 410 | modname[0] = '\0'; |
Sami Tolvanen | 8b8e6b5 | 2021-04-08 11:28:32 -0700 | [diff] [blame] | 411 | goto found; |
Alexey Dobriyan | a5c43da | 2007-05-08 00:28:47 -0700 | [diff] [blame] | 412 | } |
Manish Katiyar | ad6ccfa | 2009-05-12 13:43:35 -0700 | [diff] [blame] | 413 | /* See if it's in a module. */ |
Sami Tolvanen | 8b8e6b5 | 2021-04-08 11:28:32 -0700 | [diff] [blame] | 414 | res = lookup_module_symbol_attrs(addr, size, offset, modname, name); |
| 415 | if (res) |
| 416 | return res; |
| 417 | |
| 418 | found: |
| 419 | cleanup_symbol_name(name); |
| 420 | return 0; |
Alexey Dobriyan | a5c43da | 2007-05-08 00:28:47 -0700 | [diff] [blame] | 421 | } |
| 422 | |
Robert Peterson | 42e3808 | 2007-04-30 15:09:48 -0700 | [diff] [blame] | 423 | /* Look up a kernel symbol and return it in a text buffer. */ |
Namhyung Kim | 0f77a8d | 2011-03-24 11:42:29 +0900 | [diff] [blame] | 424 | static int __sprint_symbol(char *buffer, unsigned long address, |
Stephen Boyd | 9294523 | 2021-07-07 18:09:20 -0700 | [diff] [blame] | 425 | int symbol_offset, int add_offset, int add_buildid) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 426 | { |
| 427 | char *modname; |
Stephen Boyd | 9294523 | 2021-07-07 18:09:20 -0700 | [diff] [blame] | 428 | const unsigned char *buildid; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 429 | const char *name; |
| 430 | unsigned long offset, size; |
Hugh Dickins | 966c8c1 | 2008-11-19 15:36:36 -0800 | [diff] [blame] | 431 | int len; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 432 | |
Namhyung Kim | 0f77a8d | 2011-03-24 11:42:29 +0900 | [diff] [blame] | 433 | address += symbol_offset; |
Stephen Boyd | 9294523 | 2021-07-07 18:09:20 -0700 | [diff] [blame] | 434 | name = kallsyms_lookup_buildid(address, &size, &offset, &modname, &buildid, |
| 435 | buffer); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 436 | if (!name) |
Namhyung Kim | b86280a | 2014-08-08 14:19:41 -0700 | [diff] [blame] | 437 | return sprintf(buffer, "0x%lx", address - symbol_offset); |
Andrew Morton | 19769b7 | 2007-07-15 23:41:24 -0700 | [diff] [blame] | 438 | |
Hugh Dickins | 966c8c1 | 2008-11-19 15:36:36 -0800 | [diff] [blame] | 439 | if (name != buffer) |
| 440 | strcpy(buffer, name); |
| 441 | len = strlen(buffer); |
Namhyung Kim | 0f77a8d | 2011-03-24 11:42:29 +0900 | [diff] [blame] | 442 | offset -= symbol_offset; |
Hugh Dickins | 966c8c1 | 2008-11-19 15:36:36 -0800 | [diff] [blame] | 443 | |
Stephen Boyd | 4796dd2 | 2012-05-29 15:07:33 -0700 | [diff] [blame] | 444 | if (add_offset) |
| 445 | len += sprintf(buffer + len, "+%#lx/%#lx", offset, size); |
| 446 | |
Stephen Boyd | 9294523 | 2021-07-07 18:09:20 -0700 | [diff] [blame] | 447 | if (modname) { |
| 448 | len += sprintf(buffer + len, " [%s", modname); |
| 449 | #if IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID) |
| 450 | if (add_buildid && buildid) { |
| 451 | /* build ID should match length of sprintf */ |
| 452 | #if IS_ENABLED(CONFIG_MODULES) |
| 453 | static_assert(sizeof(typeof_member(struct module, build_id)) == 20); |
| 454 | #endif |
| 455 | len += sprintf(buffer + len, " %20phN", buildid); |
| 456 | } |
| 457 | #endif |
| 458 | len += sprintf(buffer + len, "]"); |
| 459 | } |
Hugh Dickins | 966c8c1 | 2008-11-19 15:36:36 -0800 | [diff] [blame] | 460 | |
| 461 | return len; |
Robert Peterson | 42e3808 | 2007-04-30 15:09:48 -0700 | [diff] [blame] | 462 | } |
Namhyung Kim | 0f77a8d | 2011-03-24 11:42:29 +0900 | [diff] [blame] | 463 | |
| 464 | /** |
| 465 | * sprint_symbol - Look up a kernel symbol and return it in a text buffer |
| 466 | * @buffer: buffer to be stored |
| 467 | * @address: address to lookup |
| 468 | * |
| 469 | * This function looks up a kernel symbol with @address and stores its name, |
| 470 | * offset, size and module name to @buffer if possible. If no symbol was found, |
| 471 | * just saves its @address as is. |
| 472 | * |
| 473 | * This function returns the number of bytes stored in @buffer. |
| 474 | */ |
| 475 | int sprint_symbol(char *buffer, unsigned long address) |
| 476 | { |
Stephen Boyd | 9294523 | 2021-07-07 18:09:20 -0700 | [diff] [blame] | 477 | return __sprint_symbol(buffer, address, 0, 1, 0); |
Namhyung Kim | 0f77a8d | 2011-03-24 11:42:29 +0900 | [diff] [blame] | 478 | } |
Manish Katiyar | ad6ccfa | 2009-05-12 13:43:35 -0700 | [diff] [blame] | 479 | EXPORT_SYMBOL_GPL(sprint_symbol); |
Robert Peterson | 42e3808 | 2007-04-30 15:09:48 -0700 | [diff] [blame] | 480 | |
Namhyung Kim | 0f77a8d | 2011-03-24 11:42:29 +0900 | [diff] [blame] | 481 | /** |
Stephen Boyd | 9294523 | 2021-07-07 18:09:20 -0700 | [diff] [blame] | 482 | * sprint_symbol_build_id - Look up a kernel symbol and return it in a text buffer |
| 483 | * @buffer: buffer to be stored |
| 484 | * @address: address to lookup |
| 485 | * |
| 486 | * This function looks up a kernel symbol with @address and stores its name, |
| 487 | * offset, size, module name and module build ID to @buffer if possible. If no |
| 488 | * symbol was found, just saves its @address as is. |
| 489 | * |
| 490 | * This function returns the number of bytes stored in @buffer. |
| 491 | */ |
| 492 | int sprint_symbol_build_id(char *buffer, unsigned long address) |
| 493 | { |
| 494 | return __sprint_symbol(buffer, address, 0, 1, 1); |
| 495 | } |
| 496 | EXPORT_SYMBOL_GPL(sprint_symbol_build_id); |
| 497 | |
| 498 | /** |
Stephen Boyd | 4796dd2 | 2012-05-29 15:07:33 -0700 | [diff] [blame] | 499 | * sprint_symbol_no_offset - Look up a kernel symbol and return it in a text buffer |
| 500 | * @buffer: buffer to be stored |
| 501 | * @address: address to lookup |
| 502 | * |
| 503 | * This function looks up a kernel symbol with @address and stores its name |
| 504 | * and module name to @buffer if possible. If no symbol was found, just saves |
| 505 | * its @address as is. |
| 506 | * |
| 507 | * This function returns the number of bytes stored in @buffer. |
| 508 | */ |
| 509 | int sprint_symbol_no_offset(char *buffer, unsigned long address) |
| 510 | { |
Stephen Boyd | 9294523 | 2021-07-07 18:09:20 -0700 | [diff] [blame] | 511 | return __sprint_symbol(buffer, address, 0, 0, 0); |
Stephen Boyd | 4796dd2 | 2012-05-29 15:07:33 -0700 | [diff] [blame] | 512 | } |
| 513 | EXPORT_SYMBOL_GPL(sprint_symbol_no_offset); |
| 514 | |
| 515 | /** |
Namhyung Kim | 0f77a8d | 2011-03-24 11:42:29 +0900 | [diff] [blame] | 516 | * sprint_backtrace - Look up a backtrace symbol and return it in a text buffer |
| 517 | * @buffer: buffer to be stored |
| 518 | * @address: address to lookup |
| 519 | * |
| 520 | * This function is for stack backtrace and does the same thing as |
| 521 | * sprint_symbol() but with modified/decreased @address. If there is a |
| 522 | * tail-call to the function marked "noreturn", gcc optimized out code after |
| 523 | * the call so that the stack-saved return address could point outside of the |
| 524 | * caller. This function ensures that kallsyms will find the original caller |
| 525 | * by decreasing @address. |
| 526 | * |
| 527 | * This function returns the number of bytes stored in @buffer. |
| 528 | */ |
| 529 | int sprint_backtrace(char *buffer, unsigned long address) |
| 530 | { |
Stephen Boyd | 9294523 | 2021-07-07 18:09:20 -0700 | [diff] [blame] | 531 | return __sprint_symbol(buffer, address, -1, 1, 0); |
| 532 | } |
| 533 | |
| 534 | /** |
| 535 | * sprint_backtrace_build_id - Look up a backtrace symbol and return it in a text buffer |
| 536 | * @buffer: buffer to be stored |
| 537 | * @address: address to lookup |
| 538 | * |
| 539 | * This function is for stack backtrace and does the same thing as |
| 540 | * sprint_symbol() but with modified/decreased @address. If there is a |
| 541 | * tail-call to the function marked "noreturn", gcc optimized out code after |
| 542 | * the call so that the stack-saved return address could point outside of the |
| 543 | * caller. This function ensures that kallsyms will find the original caller |
| 544 | * by decreasing @address. This function also appends the module build ID to |
| 545 | * the @buffer if @address is within a kernel module. |
| 546 | * |
| 547 | * This function returns the number of bytes stored in @buffer. |
| 548 | */ |
| 549 | int sprint_backtrace_build_id(char *buffer, unsigned long address) |
| 550 | { |
| 551 | return __sprint_symbol(buffer, address, -1, 1, 1); |
Namhyung Kim | 0f77a8d | 2011-03-24 11:42:29 +0900 | [diff] [blame] | 552 | } |
| 553 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 554 | /* To avoid using get_symbol_offset for every symbol, we carry prefix along. */ |
Manish Katiyar | ad6ccfa | 2009-05-12 13:43:35 -0700 | [diff] [blame] | 555 | struct kallsym_iter { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 556 | loff_t pos; |
Alexander Shishkin | d83212d | 2018-06-06 15:54:10 +0300 | [diff] [blame] | 557 | loff_t pos_arch_end; |
Daniel Borkmann | 74451e66 | 2017-02-16 22:24:50 +0100 | [diff] [blame] | 558 | loff_t pos_mod_end; |
Steven Rostedt (VMware) | 6171a03 | 2017-09-06 08:40:41 -0400 | [diff] [blame] | 559 | loff_t pos_ftrace_mod_end; |
Adrian Hunter | d002b8b | 2020-05-28 11:00:58 +0300 | [diff] [blame] | 560 | loff_t pos_bpf_end; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 561 | unsigned long value; |
Manish Katiyar | ad6ccfa | 2009-05-12 13:43:35 -0700 | [diff] [blame] | 562 | unsigned int nameoff; /* If iterating in core kernel symbols. */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 563 | char type; |
Tejun Heo | 9281acea | 2007-07-17 04:03:51 -0700 | [diff] [blame] | 564 | char name[KSYM_NAME_LEN]; |
| 565 | char module_name[MODULE_NAME_LEN]; |
Alexey Dobriyan | ea07890 | 2007-05-08 00:28:39 -0700 | [diff] [blame] | 566 | int exported; |
Linus Torvalds | c0f3ea1 | 2017-11-08 12:51:04 -0800 | [diff] [blame] | 567 | int show_value; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 568 | }; |
| 569 | |
Alexander Shishkin | d83212d | 2018-06-06 15:54:10 +0300 | [diff] [blame] | 570 | int __weak arch_get_kallsym(unsigned int symnum, unsigned long *value, |
| 571 | char *type, char *name) |
| 572 | { |
| 573 | return -EINVAL; |
| 574 | } |
| 575 | |
| 576 | static int get_ksymbol_arch(struct kallsym_iter *iter) |
| 577 | { |
| 578 | int ret = arch_get_kallsym(iter->pos - kallsyms_num_syms, |
| 579 | &iter->value, &iter->type, |
| 580 | iter->name); |
| 581 | |
| 582 | if (ret < 0) { |
| 583 | iter->pos_arch_end = iter->pos; |
| 584 | return 0; |
| 585 | } |
| 586 | |
| 587 | return 1; |
| 588 | } |
| 589 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 590 | static int get_ksymbol_mod(struct kallsym_iter *iter) |
| 591 | { |
Alexander Shishkin | d83212d | 2018-06-06 15:54:10 +0300 | [diff] [blame] | 592 | int ret = module_get_kallsym(iter->pos - iter->pos_arch_end, |
Daniel Borkmann | 74451e66 | 2017-02-16 22:24:50 +0100 | [diff] [blame] | 593 | &iter->value, &iter->type, |
| 594 | iter->name, iter->module_name, |
| 595 | &iter->exported); |
| 596 | if (ret < 0) { |
| 597 | iter->pos_mod_end = iter->pos; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 598 | return 0; |
Daniel Borkmann | 74451e66 | 2017-02-16 22:24:50 +0100 | [diff] [blame] | 599 | } |
| 600 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 601 | return 1; |
| 602 | } |
| 603 | |
Adrian Hunter | fc0ea79 | 2020-05-12 15:19:13 +0300 | [diff] [blame] | 604 | /* |
| 605 | * ftrace_mod_get_kallsym() may also get symbols for pages allocated for ftrace |
| 606 | * purposes. In that case "__builtin__ftrace" is used as a module name, even |
| 607 | * though "__builtin__ftrace" is not a module. |
| 608 | */ |
Steven Rostedt (VMware) | 6171a03 | 2017-09-06 08:40:41 -0400 | [diff] [blame] | 609 | static int get_ksymbol_ftrace_mod(struct kallsym_iter *iter) |
| 610 | { |
| 611 | int ret = ftrace_mod_get_kallsym(iter->pos - iter->pos_mod_end, |
| 612 | &iter->value, &iter->type, |
| 613 | iter->name, iter->module_name, |
| 614 | &iter->exported); |
| 615 | if (ret < 0) { |
| 616 | iter->pos_ftrace_mod_end = iter->pos; |
| 617 | return 0; |
| 618 | } |
| 619 | |
| 620 | return 1; |
| 621 | } |
| 622 | |
Daniel Borkmann | 74451e66 | 2017-02-16 22:24:50 +0100 | [diff] [blame] | 623 | static int get_ksymbol_bpf(struct kallsym_iter *iter) |
| 624 | { |
Adrian Hunter | d002b8b | 2020-05-28 11:00:58 +0300 | [diff] [blame] | 625 | int ret; |
| 626 | |
Song Liu | 6934058 | 2019-01-17 08:15:21 -0800 | [diff] [blame] | 627 | strlcpy(iter->module_name, "bpf", MODULE_NAME_LEN); |
Daniel Borkmann | 74451e66 | 2017-02-16 22:24:50 +0100 | [diff] [blame] | 628 | iter->exported = 0; |
Adrian Hunter | d002b8b | 2020-05-28 11:00:58 +0300 | [diff] [blame] | 629 | ret = bpf_get_kallsym(iter->pos - iter->pos_ftrace_mod_end, |
| 630 | &iter->value, &iter->type, |
| 631 | iter->name); |
| 632 | if (ret < 0) { |
| 633 | iter->pos_bpf_end = iter->pos; |
| 634 | return 0; |
| 635 | } |
| 636 | |
| 637 | return 1; |
| 638 | } |
| 639 | |
| 640 | /* |
| 641 | * This uses "__builtin__kprobes" as a module name for symbols for pages |
| 642 | * allocated for kprobes' purposes, even though "__builtin__kprobes" is not a |
| 643 | * module. |
| 644 | */ |
| 645 | static int get_ksymbol_kprobe(struct kallsym_iter *iter) |
| 646 | { |
| 647 | strlcpy(iter->module_name, "__builtin__kprobes", MODULE_NAME_LEN); |
| 648 | iter->exported = 0; |
| 649 | return kprobe_get_kallsym(iter->pos - iter->pos_bpf_end, |
| 650 | &iter->value, &iter->type, |
| 651 | iter->name) < 0 ? 0 : 1; |
Daniel Borkmann | 74451e66 | 2017-02-16 22:24:50 +0100 | [diff] [blame] | 652 | } |
| 653 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 654 | /* Returns space to next name. */ |
| 655 | static unsigned long get_ksymbol_core(struct kallsym_iter *iter) |
| 656 | { |
| 657 | unsigned off = iter->nameoff; |
| 658 | |
Alexey Dobriyan | ea07890 | 2007-05-08 00:28:39 -0700 | [diff] [blame] | 659 | iter->module_name[0] = '\0'; |
Ard Biesheuvel | 2213e9a | 2016-03-15 14:58:19 -0700 | [diff] [blame] | 660 | iter->value = kallsyms_sym_address(iter->pos); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 661 | |
| 662 | iter->type = kallsyms_get_symbol_type(off); |
| 663 | |
Chen Gang | e3f2675 | 2013-04-15 15:04:43 +0930 | [diff] [blame] | 664 | off = kallsyms_expand_symbol(off, iter->name, ARRAY_SIZE(iter->name)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 665 | |
| 666 | return off - iter->nameoff; |
| 667 | } |
| 668 | |
| 669 | static void reset_iter(struct kallsym_iter *iter, loff_t new_pos) |
| 670 | { |
| 671 | iter->name[0] = '\0'; |
| 672 | iter->nameoff = get_symbol_offset(new_pos); |
| 673 | iter->pos = new_pos; |
Steven Rostedt (VMware) | 6171a03 | 2017-09-06 08:40:41 -0400 | [diff] [blame] | 674 | if (new_pos == 0) { |
Alexander Shishkin | d83212d | 2018-06-06 15:54:10 +0300 | [diff] [blame] | 675 | iter->pos_arch_end = 0; |
Daniel Borkmann | 74451e66 | 2017-02-16 22:24:50 +0100 | [diff] [blame] | 676 | iter->pos_mod_end = 0; |
Steven Rostedt (VMware) | 6171a03 | 2017-09-06 08:40:41 -0400 | [diff] [blame] | 677 | iter->pos_ftrace_mod_end = 0; |
Adrian Hunter | d002b8b | 2020-05-28 11:00:58 +0300 | [diff] [blame] | 678 | iter->pos_bpf_end = 0; |
Steven Rostedt (VMware) | 6171a03 | 2017-09-06 08:40:41 -0400 | [diff] [blame] | 679 | } |
Daniel Borkmann | 74451e66 | 2017-02-16 22:24:50 +0100 | [diff] [blame] | 680 | } |
| 681 | |
Adrian Hunter | b966794 | 2018-06-06 15:54:09 +0300 | [diff] [blame] | 682 | /* |
| 683 | * The end position (last + 1) of each additional kallsyms section is recorded |
| 684 | * in iter->pos_..._end as each section is added, and so can be used to |
| 685 | * determine which get_ksymbol_...() function to call next. |
| 686 | */ |
Daniel Borkmann | 74451e66 | 2017-02-16 22:24:50 +0100 | [diff] [blame] | 687 | static int update_iter_mod(struct kallsym_iter *iter, loff_t pos) |
| 688 | { |
| 689 | iter->pos = pos; |
| 690 | |
Alexander Shishkin | d83212d | 2018-06-06 15:54:10 +0300 | [diff] [blame] | 691 | if ((!iter->pos_arch_end || iter->pos_arch_end > pos) && |
| 692 | get_ksymbol_arch(iter)) |
| 693 | return 1; |
| 694 | |
Adrian Hunter | b966794 | 2018-06-06 15:54:09 +0300 | [diff] [blame] | 695 | if ((!iter->pos_mod_end || iter->pos_mod_end > pos) && |
| 696 | get_ksymbol_mod(iter)) |
Steven Rostedt (VMware) | 6171a03 | 2017-09-06 08:40:41 -0400 | [diff] [blame] | 697 | return 1; |
Steven Rostedt (VMware) | 6171a03 | 2017-09-06 08:40:41 -0400 | [diff] [blame] | 698 | |
Adrian Hunter | b966794 | 2018-06-06 15:54:09 +0300 | [diff] [blame] | 699 | if ((!iter->pos_ftrace_mod_end || iter->pos_ftrace_mod_end > pos) && |
| 700 | get_ksymbol_ftrace_mod(iter)) |
| 701 | return 1; |
Daniel Borkmann | 74451e66 | 2017-02-16 22:24:50 +0100 | [diff] [blame] | 702 | |
Adrian Hunter | d002b8b | 2020-05-28 11:00:58 +0300 | [diff] [blame] | 703 | if ((!iter->pos_bpf_end || iter->pos_bpf_end > pos) && |
| 704 | get_ksymbol_bpf(iter)) |
| 705 | return 1; |
| 706 | |
| 707 | return get_ksymbol_kprobe(iter); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 708 | } |
| 709 | |
| 710 | /* Returns false if pos at or past end of file. */ |
| 711 | static int update_iter(struct kallsym_iter *iter, loff_t pos) |
| 712 | { |
| 713 | /* Module symbols can be accessed randomly. */ |
Daniel Borkmann | 74451e66 | 2017-02-16 22:24:50 +0100 | [diff] [blame] | 714 | if (pos >= kallsyms_num_syms) |
| 715 | return update_iter_mod(iter, pos); |
Manish Katiyar | ad6ccfa | 2009-05-12 13:43:35 -0700 | [diff] [blame] | 716 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 717 | /* If we're not on the desired position, reset to new position. */ |
| 718 | if (pos != iter->pos) |
| 719 | reset_iter(iter, pos); |
| 720 | |
| 721 | iter->nameoff += get_ksymbol_core(iter); |
| 722 | iter->pos++; |
| 723 | |
| 724 | return 1; |
| 725 | } |
| 726 | |
| 727 | static void *s_next(struct seq_file *m, void *p, loff_t *pos) |
| 728 | { |
| 729 | (*pos)++; |
| 730 | |
| 731 | if (!update_iter(m->private, *pos)) |
| 732 | return NULL; |
| 733 | return p; |
| 734 | } |
| 735 | |
| 736 | static void *s_start(struct seq_file *m, loff_t *pos) |
| 737 | { |
| 738 | if (!update_iter(m->private, *pos)) |
| 739 | return NULL; |
| 740 | return m->private; |
| 741 | } |
| 742 | |
| 743 | static void s_stop(struct seq_file *m, void *p) |
| 744 | { |
| 745 | } |
| 746 | |
| 747 | static int s_show(struct seq_file *m, void *p) |
| 748 | { |
Linus Torvalds | 668533d | 2017-11-29 10:30:13 -0800 | [diff] [blame] | 749 | void *value; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 750 | struct kallsym_iter *iter = m->private; |
| 751 | |
Manish Katiyar | ad6ccfa | 2009-05-12 13:43:35 -0700 | [diff] [blame] | 752 | /* Some debugging symbols have no name. Ignore them. */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 753 | if (!iter->name[0]) |
| 754 | return 0; |
| 755 | |
Linus Torvalds | 668533d | 2017-11-29 10:30:13 -0800 | [diff] [blame] | 756 | value = iter->show_value ? (void *)iter->value : NULL; |
Linus Torvalds | c0f3ea1 | 2017-11-08 12:51:04 -0800 | [diff] [blame] | 757 | |
Alexey Dobriyan | ea07890 | 2007-05-08 00:28:39 -0700 | [diff] [blame] | 758 | if (iter->module_name[0]) { |
| 759 | char type; |
| 760 | |
Manish Katiyar | ad6ccfa | 2009-05-12 13:43:35 -0700 | [diff] [blame] | 761 | /* |
| 762 | * Label it "global" if it is exported, |
| 763 | * "local" if not exported. |
| 764 | */ |
Alexey Dobriyan | ea07890 | 2007-05-08 00:28:39 -0700 | [diff] [blame] | 765 | type = iter->exported ? toupper(iter->type) : |
| 766 | tolower(iter->type); |
Linus Torvalds | 668533d | 2017-11-29 10:30:13 -0800 | [diff] [blame] | 767 | seq_printf(m, "%px %c %s\t[%s]\n", value, |
Kees Cook | 9f36e2c | 2011-03-22 16:34:22 -0700 | [diff] [blame] | 768 | type, iter->name, iter->module_name); |
Alexey Dobriyan | ea07890 | 2007-05-08 00:28:39 -0700 | [diff] [blame] | 769 | } else |
Linus Torvalds | 668533d | 2017-11-29 10:30:13 -0800 | [diff] [blame] | 770 | seq_printf(m, "%px %c %s\n", value, |
Kees Cook | 9f36e2c | 2011-03-22 16:34:22 -0700 | [diff] [blame] | 771 | iter->type, iter->name); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 772 | return 0; |
| 773 | } |
| 774 | |
Helge Deller | 15ad7cd | 2006-12-06 20:40:36 -0800 | [diff] [blame] | 775 | static const struct seq_operations kallsyms_op = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 776 | .start = s_start, |
| 777 | .next = s_next, |
| 778 | .stop = s_stop, |
| 779 | .show = s_show |
| 780 | }; |
| 781 | |
Alan Maguire | 647cafa | 2022-07-12 13:31:44 +0100 | [diff] [blame] | 782 | #ifdef CONFIG_BPF_SYSCALL |
| 783 | |
| 784 | struct bpf_iter__ksym { |
| 785 | __bpf_md_ptr(struct bpf_iter_meta *, meta); |
| 786 | __bpf_md_ptr(struct kallsym_iter *, ksym); |
| 787 | }; |
| 788 | |
| 789 | static int ksym_prog_seq_show(struct seq_file *m, bool in_stop) |
| 790 | { |
| 791 | struct bpf_iter__ksym ctx; |
| 792 | struct bpf_iter_meta meta; |
| 793 | struct bpf_prog *prog; |
| 794 | |
| 795 | meta.seq = m; |
| 796 | prog = bpf_iter_get_info(&meta, in_stop); |
| 797 | if (!prog) |
| 798 | return 0; |
| 799 | |
| 800 | ctx.meta = &meta; |
| 801 | ctx.ksym = m ? m->private : NULL; |
| 802 | return bpf_iter_run_prog(prog, &ctx); |
| 803 | } |
| 804 | |
| 805 | static int bpf_iter_ksym_seq_show(struct seq_file *m, void *p) |
| 806 | { |
| 807 | return ksym_prog_seq_show(m, false); |
| 808 | } |
| 809 | |
| 810 | static void bpf_iter_ksym_seq_stop(struct seq_file *m, void *p) |
| 811 | { |
| 812 | if (!p) |
| 813 | (void) ksym_prog_seq_show(m, true); |
| 814 | else |
| 815 | s_stop(m, p); |
| 816 | } |
| 817 | |
| 818 | static const struct seq_operations bpf_iter_ksym_ops = { |
| 819 | .start = s_start, |
| 820 | .next = s_next, |
| 821 | .stop = bpf_iter_ksym_seq_stop, |
| 822 | .show = bpf_iter_ksym_seq_show, |
| 823 | }; |
| 824 | |
| 825 | static int bpf_iter_ksym_init(void *priv_data, struct bpf_iter_aux_info *aux) |
| 826 | { |
| 827 | struct kallsym_iter *iter = priv_data; |
| 828 | |
| 829 | reset_iter(iter, 0); |
| 830 | |
| 831 | /* cache here as in kallsyms_open() case; use current process |
| 832 | * credentials to tell BPF iterators if values should be shown. |
| 833 | */ |
| 834 | iter->show_value = kallsyms_show_value(current_cred()); |
| 835 | |
| 836 | return 0; |
| 837 | } |
| 838 | |
| 839 | DEFINE_BPF_ITER_FUNC(ksym, struct bpf_iter_meta *meta, struct kallsym_iter *ksym) |
| 840 | |
| 841 | static const struct bpf_iter_seq_info ksym_iter_seq_info = { |
| 842 | .seq_ops = &bpf_iter_ksym_ops, |
| 843 | .init_seq_private = bpf_iter_ksym_init, |
| 844 | .fini_seq_private = NULL, |
| 845 | .seq_priv_size = sizeof(struct kallsym_iter), |
| 846 | }; |
| 847 | |
| 848 | static struct bpf_iter_reg ksym_iter_reg_info = { |
| 849 | .target = "ksym", |
| 850 | .feature = BPF_ITER_RESCHED, |
| 851 | .ctx_arg_info_size = 1, |
| 852 | .ctx_arg_info = { |
| 853 | { offsetof(struct bpf_iter__ksym, ksym), |
| 854 | PTR_TO_BTF_ID_OR_NULL }, |
| 855 | }, |
| 856 | .seq_info = &ksym_iter_seq_info, |
| 857 | }; |
| 858 | |
| 859 | BTF_ID_LIST(btf_ksym_iter_id) |
| 860 | BTF_ID(struct, kallsym_iter) |
| 861 | |
| 862 | static int __init bpf_ksym_iter_register(void) |
| 863 | { |
| 864 | ksym_iter_reg_info.ctx_arg_info[0].btf_id = *btf_ksym_iter_id; |
| 865 | return bpf_iter_reg_target(&ksym_iter_reg_info); |
| 866 | } |
| 867 | |
| 868 | late_initcall(bpf_ksym_iter_register); |
| 869 | |
| 870 | #endif /* CONFIG_BPF_SYSCALL */ |
| 871 | |
Linus Torvalds | c0f3ea1 | 2017-11-08 12:51:04 -0800 | [diff] [blame] | 872 | static inline int kallsyms_for_perf(void) |
| 873 | { |
| 874 | #ifdef CONFIG_PERF_EVENTS |
| 875 | extern int sysctl_perf_event_paranoid; |
| 876 | if (sysctl_perf_event_paranoid <= 1) |
| 877 | return 1; |
| 878 | #endif |
| 879 | return 0; |
| 880 | } |
| 881 | |
| 882 | /* |
| 883 | * We show kallsyms information even to normal users if we've enabled |
| 884 | * kernel profiling and are explicitly not paranoid (so kptr_restrict |
| 885 | * is clear, and sysctl_perf_event_paranoid isn't set). |
| 886 | * |
| 887 | * Otherwise, require CAP_SYSLOG (assuming kptr_restrict isn't set to |
| 888 | * block even that). |
| 889 | */ |
Kees Cook | 1602518 | 2020-07-02 11:49:23 -0700 | [diff] [blame] | 890 | bool kallsyms_show_value(const struct cred *cred) |
Linus Torvalds | c0f3ea1 | 2017-11-08 12:51:04 -0800 | [diff] [blame] | 891 | { |
| 892 | switch (kptr_restrict) { |
| 893 | case 0: |
| 894 | if (kallsyms_for_perf()) |
Kees Cook | 1602518 | 2020-07-02 11:49:23 -0700 | [diff] [blame] | 895 | return true; |
Gustavo A. R. Silva | df561f66 | 2020-08-23 17:36:59 -0500 | [diff] [blame] | 896 | fallthrough; |
Linus Torvalds | c0f3ea1 | 2017-11-08 12:51:04 -0800 | [diff] [blame] | 897 | case 1: |
Kees Cook | 1602518 | 2020-07-02 11:49:23 -0700 | [diff] [blame] | 898 | if (security_capable(cred, &init_user_ns, CAP_SYSLOG, |
| 899 | CAP_OPT_NOAUDIT) == 0) |
| 900 | return true; |
Gustavo A. R. Silva | df561f66 | 2020-08-23 17:36:59 -0500 | [diff] [blame] | 901 | fallthrough; |
Linus Torvalds | c0f3ea1 | 2017-11-08 12:51:04 -0800 | [diff] [blame] | 902 | default: |
Kees Cook | 1602518 | 2020-07-02 11:49:23 -0700 | [diff] [blame] | 903 | return false; |
Linus Torvalds | c0f3ea1 | 2017-11-08 12:51:04 -0800 | [diff] [blame] | 904 | } |
| 905 | } |
| 906 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 907 | static int kallsyms_open(struct inode *inode, struct file *file) |
| 908 | { |
Manish Katiyar | ad6ccfa | 2009-05-12 13:43:35 -0700 | [diff] [blame] | 909 | /* |
| 910 | * We keep iterator in m->private, since normal case is to |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 911 | * s_start from where we left off, so we avoid doing |
Manish Katiyar | ad6ccfa | 2009-05-12 13:43:35 -0700 | [diff] [blame] | 912 | * using get_symbol_offset for every symbol. |
| 913 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 914 | struct kallsym_iter *iter; |
Rob Jones | 0049f26 | 2014-10-13 15:52:10 -0700 | [diff] [blame] | 915 | iter = __seq_open_private(file, &kallsyms_op, sizeof(*iter)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 916 | if (!iter) |
| 917 | return -ENOMEM; |
| 918 | reset_iter(iter, 0); |
| 919 | |
Kees Cook | 1602518 | 2020-07-02 11:49:23 -0700 | [diff] [blame] | 920 | /* |
| 921 | * Instead of checking this on every s_show() call, cache |
| 922 | * the result here at open time. |
| 923 | */ |
| 924 | iter->show_value = kallsyms_show_value(file->f_cred); |
Rob Jones | 0049f26 | 2014-10-13 15:52:10 -0700 | [diff] [blame] | 925 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 926 | } |
| 927 | |
Jason Wessel | 67fc4e0 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 928 | #ifdef CONFIG_KGDB_KDB |
| 929 | const char *kdb_walk_kallsyms(loff_t *pos) |
| 930 | { |
| 931 | static struct kallsym_iter kdb_walk_kallsyms_iter; |
| 932 | if (*pos == 0) { |
| 933 | memset(&kdb_walk_kallsyms_iter, 0, |
| 934 | sizeof(kdb_walk_kallsyms_iter)); |
| 935 | reset_iter(&kdb_walk_kallsyms_iter, 0); |
| 936 | } |
| 937 | while (1) { |
| 938 | if (!update_iter(&kdb_walk_kallsyms_iter, *pos)) |
| 939 | return NULL; |
| 940 | ++*pos; |
| 941 | /* Some debugging symbols have no name. Ignore them. */ |
| 942 | if (kdb_walk_kallsyms_iter.name[0]) |
| 943 | return kdb_walk_kallsyms_iter.name; |
| 944 | } |
| 945 | } |
| 946 | #endif /* CONFIG_KGDB_KDB */ |
| 947 | |
Alexey Dobriyan | 97a3253 | 2020-02-03 17:37:17 -0800 | [diff] [blame] | 948 | static const struct proc_ops kallsyms_proc_ops = { |
| 949 | .proc_open = kallsyms_open, |
| 950 | .proc_read = seq_read, |
| 951 | .proc_lseek = seq_lseek, |
| 952 | .proc_release = seq_release_private, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 953 | }; |
| 954 | |
| 955 | static int __init kallsyms_init(void) |
| 956 | { |
Alexey Dobriyan | 97a3253 | 2020-02-03 17:37:17 -0800 | [diff] [blame] | 957 | proc_create("kallsyms", 0444, NULL, &kallsyms_proc_ops); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 958 | return 0; |
| 959 | } |
Manish Katiyar | ad6ccfa | 2009-05-12 13:43:35 -0700 | [diff] [blame] | 960 | device_initcall(kallsyms_init); |