1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Test the function and performance of kallsyms 4 * 5 * Copyright (C) Huawei Technologies Co., Ltd., 2022 6 * 7 * Authors: Zhen Lei <thunder.leizhen@huawei.com> Huawei 8 */ 9 10 #define pr_fmt(fmt) "kallsyms_selftest: " fmt 11 12 #include <linux/init.h> 13 #include <linux/module.h> 14 #include <linux/kallsyms.h> 15 #include <linux/random.h> 16 #include <linux/sched/clock.h> 17 #include <linux/kthread.h> 18 #include <linux/vmalloc.h> 19 20 #include "kallsyms_internal.h" 21 #include "kallsyms_selftest.h" 22 23 24 #define MAX_NUM_OF_RECORDS 64 25 26 struct test_stat { 27 int min; 28 int max; 29 int save_cnt; 30 int real_cnt; 31 int perf; 32 u64 sum; 33 char *name; 34 unsigned long addr; 35 unsigned long addrs[MAX_NUM_OF_RECORDS]; 36 }; 37 38 struct test_item { 39 char *name; 40 unsigned long addr; 41 }; 42 43 #define ITEM_FUNC(s) \ 44 { \ 45 .name = #s, \ 46 .addr = (unsigned long)s, \ 47 } 48 49 #define ITEM_DATA(s) \ 50 { \ 51 .name = #s, \ 52 .addr = (unsigned long)&s, \ 53 } 54 55 56 static int kallsyms_test_var_bss_static; 57 static int kallsyms_test_var_data_static = 1; 58 int kallsyms_test_var_bss; 59 int kallsyms_test_var_data = 1; 60 61 static int kallsyms_test_func_static(void) 62 { 63 kallsyms_test_var_bss_static++; 64 kallsyms_test_var_data_static++; 65 66 return 0; 67 } 68 69 int kallsyms_test_func(void) 70 { 71 return kallsyms_test_func_static(); 72 } 73 74 __weak int kallsyms_test_func_weak(void) 75 { 76 kallsyms_test_var_bss++; 77 kallsyms_test_var_data++; 78 return 0; 79 } 80 81 static struct test_item test_items[] = { 82 ITEM_FUNC(kallsyms_test_func_static), 83 ITEM_FUNC(kallsyms_test_func), 84 ITEM_FUNC(kallsyms_test_func_weak), 85 ITEM_FUNC(vmalloc), 86 ITEM_FUNC(vfree), 87 #ifdef CONFIG_KALLSYMS_ALL 88 ITEM_DATA(kallsyms_test_var_bss_static), 89 ITEM_DATA(kallsyms_test_var_data_static), 90 ITEM_DATA(kallsyms_test_var_bss), 91 ITEM_DATA(kallsyms_test_var_data), 92 ITEM_DATA(vmap_area_list), 93 #endif 94 }; 95 96 static char stub_name[KSYM_NAME_LEN]; 97 98 static int stat_symbol_len(void *data, const char *name, struct module *mod, unsigned long addr) 99 { 100 *(u32 *)data += strlen(name); 101 102 return 0; 103 } 104 105 static void test_kallsyms_compression_ratio(void) 106 { 107 u32 pos, off, len, num; 108 u32 ratio, total_size, total_len = 0; 109 110 kallsyms_on_each_symbol(stat_symbol_len, &total_len); 111 112 /* 113 * A symbol name cannot start with a number. This stub name helps us 114 * traverse the entire symbol table without finding a match. It's used 115 * for subsequent performance tests, and its length is the average 116 * length of all symbol names. 117 */ 118 memset(stub_name, '4', sizeof(stub_name)); 119 pos = total_len / kallsyms_num_syms; 120 stub_name[pos] = 0; 121 122 pos = 0; 123 num = 0; 124 off = 0; 125 while (pos < kallsyms_num_syms) { 126 len = kallsyms_names[off]; 127 num++; 128 off++; 129 pos++; 130 if ((len & 0x80) != 0) { 131 len = (len & 0x7f) | (kallsyms_names[off] << 7); 132 num++; 133 off++; 134 } 135 off += len; 136 } 137 138 /* 139 * 1. The length fields is not counted 140 * 2. The memory occupied by array kallsyms_token_table[] and 141 * kallsyms_token_index[] needs to be counted. 142 */ 143 total_size = off - num; 144 pos = kallsyms_token_index[0xff]; 145 total_size += pos + strlen(&kallsyms_token_table[pos]) + 1; 146 total_size += 0x100 * sizeof(u16); 147 148 pr_info(" ---------------------------------------------------------\n"); 149 pr_info("| nr_symbols | compressed size | original size | ratio(%%) |\n"); 150 pr_info("|---------------------------------------------------------|\n"); 151 ratio = (u32)div_u64(10000ULL * total_size, total_len); 152 pr_info("| %10d | %10d | %10d | %2d.%-2d |\n", 153 kallsyms_num_syms, total_size, total_len, ratio / 100, ratio % 100); 154 pr_info(" ---------------------------------------------------------\n"); 155 } 156 157 static int lookup_name(void *data, const char *name, struct module *mod, unsigned long addr) 158 { 159 u64 t0, t1, t; 160 struct test_stat *stat = (struct test_stat *)data; 161 162 t0 = ktime_get_ns(); 163 (void)kallsyms_lookup_name(name); 164 t1 = ktime_get_ns(); 165 166 t = t1 - t0; 167 if (t < stat->min) 168 stat->min = t; 169 170 if (t > stat->max) 171 stat->max = t; 172 173 stat->real_cnt++; 174 stat->sum += t; 175 176 return 0; 177 } 178 179 static void test_perf_kallsyms_lookup_name(void) 180 { 181 struct test_stat stat; 182 183 memset(&stat, 0, sizeof(stat)); 184 stat.min = INT_MAX; 185 kallsyms_on_each_symbol(lookup_name, &stat); 186 pr_info("kallsyms_lookup_name() looked up %d symbols\n", stat.real_cnt); 187 pr_info("The time spent on each symbol is (ns): min=%d, max=%d, avg=%lld\n", 188 stat.min, stat.max, div_u64(stat.sum, stat.real_cnt)); 189 } 190 191 static bool match_cleanup_name(const char *s, const char *name) 192 { 193 char *p; 194 int len; 195 196 if (!IS_ENABLED(CONFIG_LTO_CLANG)) 197 return false; 198 199 p = strchr(s, '.'); 200 if (!p) 201 return false; 202 203 len = strlen(name); 204 if (p - s != len) 205 return false; 206 207 return !strncmp(s, name, len); 208 } 209 210 static int find_symbol(void *data, const char *name, struct module *mod, unsigned long addr) 211 { 212 struct test_stat *stat = (struct test_stat *)data; 213 214 if (strcmp(name, stat->name) == 0 || 215 (!stat->perf && match_cleanup_name(name, stat->name))) { 216 stat->real_cnt++; 217 stat->addr = addr; 218 219 if (stat->save_cnt < MAX_NUM_OF_RECORDS) { 220 stat->addrs[stat->save_cnt] = addr; 221 stat->save_cnt++; 222 } 223 224 if (stat->real_cnt == stat->max) 225 return 1; 226 } 227 228 return 0; 229 } 230 231 static void test_perf_kallsyms_on_each_symbol(void) 232 { 233 u64 t0, t1; 234 struct test_stat stat; 235 236 memset(&stat, 0, sizeof(stat)); 237 stat.max = INT_MAX; 238 stat.name = stub_name; 239 stat.perf = 1; 240 t0 = ktime_get_ns(); 241 kallsyms_on_each_symbol(find_symbol, &stat); 242 t1 = ktime_get_ns(); 243 pr_info("kallsyms_on_each_symbol() traverse all: %lld ns\n", t1 - t0); 244 } 245 246 static int match_symbol(void *data, unsigned long addr) 247 { 248 struct test_stat *stat = (struct test_stat *)data; 249 250 stat->real_cnt++; 251 stat->addr = addr; 252 253 if (stat->save_cnt < MAX_NUM_OF_RECORDS) { 254 stat->addrs[stat->save_cnt] = addr; 255 stat->save_cnt++; 256 } 257 258 if (stat->real_cnt == stat->max) 259 return 1; 260 261 return 0; 262 } 263 264 static void test_perf_kallsyms_on_each_match_symbol(void) 265 { 266 u64 t0, t1; 267 struct test_stat stat; 268 269 memset(&stat, 0, sizeof(stat)); 270 stat.max = INT_MAX; 271 stat.name = stub_name; 272 t0 = ktime_get_ns(); 273 kallsyms_on_each_match_symbol(match_symbol, stat.name, &stat); 274 t1 = ktime_get_ns(); 275 pr_info("kallsyms_on_each_match_symbol() traverse all: %lld ns\n", t1 - t0); 276 } 277 278 static int test_kallsyms_basic_function(void) 279 { 280 int i, j, ret; 281 int next = 0, nr_failed = 0; 282 char *prefix; 283 unsigned short rand; 284 unsigned long addr, lookup_addr; 285 char namebuf[KSYM_NAME_LEN]; 286 struct test_stat *stat, *stat2; 287 288 stat = kmalloc(sizeof(*stat) * 2, GFP_KERNEL); 289 if (!stat) 290 return -ENOMEM; 291 stat2 = stat + 1; 292 293 prefix = "kallsyms_lookup_name() for"; 294 for (i = 0; i < ARRAY_SIZE(test_items); i++) { 295 addr = kallsyms_lookup_name(test_items[i].name); 296 if (addr != test_items[i].addr) { 297 nr_failed++; 298 pr_info("%s %s failed: addr=%lx, expect %lx\n", 299 prefix, test_items[i].name, addr, test_items[i].addr); 300 } 301 } 302 303 prefix = "kallsyms_on_each_symbol() for"; 304 for (i = 0; i < ARRAY_SIZE(test_items); i++) { 305 memset(stat, 0, sizeof(*stat)); 306 stat->max = INT_MAX; 307 stat->name = test_items[i].name; 308 kallsyms_on_each_symbol(find_symbol, stat); 309 if (stat->addr != test_items[i].addr || stat->real_cnt != 1) { 310 nr_failed++; 311 pr_info("%s %s failed: count=%d, addr=%lx, expect %lx\n", 312 prefix, test_items[i].name, 313 stat->real_cnt, stat->addr, test_items[i].addr); 314 } 315 } 316 317 prefix = "kallsyms_on_each_match_symbol() for"; 318 for (i = 0; i < ARRAY_SIZE(test_items); i++) { 319 memset(stat, 0, sizeof(*stat)); 320 stat->max = INT_MAX; 321 stat->name = test_items[i].name; 322 kallsyms_on_each_match_symbol(match_symbol, test_items[i].name, stat); 323 if (stat->addr != test_items[i].addr || stat->real_cnt != 1) { 324 nr_failed++; 325 pr_info("%s %s failed: count=%d, addr=%lx, expect %lx\n", 326 prefix, test_items[i].name, 327 stat->real_cnt, stat->addr, test_items[i].addr); 328 } 329 } 330 331 if (nr_failed) { 332 kfree(stat); 333 return -ESRCH; 334 } 335 336 for (i = 0; i < kallsyms_num_syms; i++) { 337 addr = kallsyms_sym_address(i); 338 if (!is_ksym_addr(addr)) 339 continue; 340 341 ret = lookup_symbol_name(addr, namebuf); 342 if (unlikely(ret)) { 343 namebuf[0] = 0; 344 goto failed; 345 } 346 347 /* 348 * The first '.' may be the initial letter, in which case the 349 * entire symbol name will be truncated to an empty string in 350 * cleanup_symbol_name(). Do not test these symbols. 351 * 352 * For example: 353 * cat /proc/kallsyms | awk '{print $3}' | grep -E "^\." | head 354 * .E_read_words 355 * .E_leading_bytes 356 * .E_trailing_bytes 357 * .E_write_words 358 * .E_copy 359 * .str.292.llvm.12122243386960820698 360 * .str.24.llvm.12122243386960820698 361 * .str.29.llvm.12122243386960820698 362 * .str.75.llvm.12122243386960820698 363 * .str.99.llvm.12122243386960820698 364 */ 365 if (IS_ENABLED(CONFIG_LTO_CLANG) && !namebuf[0]) 366 continue; 367 368 lookup_addr = kallsyms_lookup_name(namebuf); 369 370 memset(stat, 0, sizeof(*stat)); 371 stat->max = INT_MAX; 372 kallsyms_on_each_match_symbol(match_symbol, namebuf, stat); 373 374 /* 375 * kallsyms_on_each_symbol() is too slow, randomly select some 376 * symbols for test. 377 */ 378 if (i >= next) { 379 memset(stat2, 0, sizeof(*stat2)); 380 stat2->max = INT_MAX; 381 stat2->name = namebuf; 382 kallsyms_on_each_symbol(find_symbol, stat2); 383 384 /* 385 * kallsyms_on_each_symbol() and kallsyms_on_each_match_symbol() 386 * need to get the same traversal result. 387 */ 388 if (stat->addr != stat2->addr || 389 stat->real_cnt != stat2->real_cnt || 390 memcmp(stat->addrs, stat2->addrs, 391 stat->save_cnt * sizeof(stat->addrs[0]))) 392 goto failed; 393 394 /* 395 * The average of random increments is 128, that is, one of 396 * them is tested every 128 symbols. 397 */ 398 get_random_bytes(&rand, sizeof(rand)); 399 next = i + (rand & 0xff) + 1; 400 } 401 402 /* Need to be found at least once */ 403 if (!stat->real_cnt) 404 goto failed; 405 406 /* 407 * kallsyms_lookup_name() returns the address of the first 408 * symbol found and cannot be NULL. 409 */ 410 if (!lookup_addr || lookup_addr != stat->addrs[0]) 411 goto failed; 412 413 /* 414 * If the addresses of all matching symbols are recorded, the 415 * target address needs to be exist. 416 */ 417 if (stat->real_cnt <= MAX_NUM_OF_RECORDS) { 418 for (j = 0; j < stat->save_cnt; j++) { 419 if (stat->addrs[j] == addr) 420 break; 421 } 422 423 if (j == stat->save_cnt) 424 goto failed; 425 } 426 } 427 428 kfree(stat); 429 430 return 0; 431 432 failed: 433 pr_info("Test for %dth symbol failed: (%s) addr=%lx", i, namebuf, addr); 434 kfree(stat); 435 return -ESRCH; 436 } 437 438 static int test_entry(void *p) 439 { 440 int ret; 441 442 do { 443 schedule_timeout(5 * HZ); 444 } while (system_state != SYSTEM_RUNNING); 445 446 pr_info("start\n"); 447 ret = test_kallsyms_basic_function(); 448 if (ret) { 449 pr_info("abort\n"); 450 return 0; 451 } 452 453 test_kallsyms_compression_ratio(); 454 test_perf_kallsyms_lookup_name(); 455 test_perf_kallsyms_on_each_symbol(); 456 test_perf_kallsyms_on_each_match_symbol(); 457 pr_info("finish\n"); 458 459 return 0; 460 } 461 462 static int __init kallsyms_test_init(void) 463 { 464 struct task_struct *t; 465 466 t = kthread_create(test_entry, NULL, "kallsyms_test"); 467 if (IS_ERR(t)) { 468 pr_info("Create kallsyms selftest task failed\n"); 469 return PTR_ERR(t); 470 } 471 kthread_bind(t, 0); 472 wake_up_process(t); 473 474 return 0; 475 } 476 late_initcall(kallsyms_test_init); 477