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 #endif 93 }; 94 95 static char stub_name[KSYM_NAME_LEN]; 96 97 static int stat_symbol_len(void *data, const char *name, unsigned long addr) 98 { 99 *(u32 *)data += strlen(name); 100 101 return 0; 102 } 103 104 static void test_kallsyms_compression_ratio(void) 105 { 106 u32 pos, off, len, num; 107 u32 ratio, total_size, total_len = 0; 108 109 kallsyms_on_each_symbol(stat_symbol_len, &total_len); 110 111 /* 112 * A symbol name cannot start with a number. This stub name helps us 113 * traverse the entire symbol table without finding a match. It's used 114 * for subsequent performance tests, and its length is the average 115 * length of all symbol names. 116 */ 117 memset(stub_name, '4', sizeof(stub_name)); 118 pos = total_len / kallsyms_num_syms; 119 stub_name[pos] = 0; 120 121 pos = 0; 122 num = 0; 123 off = 0; 124 while (pos < kallsyms_num_syms) { 125 len = kallsyms_names[off]; 126 num++; 127 off++; 128 pos++; 129 if ((len & 0x80) != 0) { 130 len = (len & 0x7f) | (kallsyms_names[off] << 7); 131 num++; 132 off++; 133 } 134 off += len; 135 } 136 137 /* 138 * 1. The length fields is not counted 139 * 2. The memory occupied by array kallsyms_token_table[] and 140 * kallsyms_token_index[] needs to be counted. 141 */ 142 total_size = off - num; 143 pos = kallsyms_token_index[0xff]; 144 total_size += pos + strlen(&kallsyms_token_table[pos]) + 1; 145 total_size += 0x100 * sizeof(u16); 146 147 pr_info(" ---------------------------------------------------------\n"); 148 pr_info("| nr_symbols | compressed size | original size | ratio(%%) |\n"); 149 pr_info("|---------------------------------------------------------|\n"); 150 ratio = (u32)div_u64(10000ULL * total_size, total_len); 151 pr_info("| %10d | %10d | %10d | %2d.%-2d |\n", 152 kallsyms_num_syms, total_size, total_len, ratio / 100, ratio % 100); 153 pr_info(" ---------------------------------------------------------\n"); 154 } 155 156 static int lookup_name(void *data, const char *name, unsigned long addr) 157 { 158 u64 t0, t1, t; 159 struct test_stat *stat = (struct test_stat *)data; 160 161 t0 = ktime_get_ns(); 162 (void)kallsyms_lookup_name(name); 163 t1 = ktime_get_ns(); 164 165 t = t1 - t0; 166 if (t < stat->min) 167 stat->min = t; 168 169 if (t > stat->max) 170 stat->max = t; 171 172 stat->real_cnt++; 173 stat->sum += t; 174 175 return 0; 176 } 177 178 static void test_perf_kallsyms_lookup_name(void) 179 { 180 struct test_stat stat; 181 182 memset(&stat, 0, sizeof(stat)); 183 stat.min = INT_MAX; 184 kallsyms_on_each_symbol(lookup_name, &stat); 185 pr_info("kallsyms_lookup_name() looked up %d symbols\n", stat.real_cnt); 186 pr_info("The time spent on each symbol is (ns): min=%d, max=%d, avg=%lld\n", 187 stat.min, stat.max, div_u64(stat.sum, stat.real_cnt)); 188 } 189 190 static bool match_cleanup_name(const char *s, const char *name) 191 { 192 char *p; 193 int len; 194 195 if (!IS_ENABLED(CONFIG_LTO_CLANG)) 196 return false; 197 198 p = strstr(s, ".llvm."); 199 if (!p) 200 return false; 201 202 len = strlen(name); 203 if (p - s != len) 204 return false; 205 206 return !strncmp(s, name, len); 207 } 208 209 static int find_symbol(void *data, const char *name, unsigned long addr) 210 { 211 struct test_stat *stat = (struct test_stat *)data; 212 213 if (strcmp(name, stat->name) == 0 || 214 (!stat->perf && match_cleanup_name(name, stat->name))) { 215 stat->real_cnt++; 216 stat->addr = addr; 217 218 if (stat->save_cnt < MAX_NUM_OF_RECORDS) { 219 stat->addrs[stat->save_cnt] = addr; 220 stat->save_cnt++; 221 } 222 223 if (stat->real_cnt == stat->max) 224 return 1; 225 } 226 227 return 0; 228 } 229 230 static void test_perf_kallsyms_on_each_symbol(void) 231 { 232 u64 t0, t1; 233 struct test_stat stat; 234 235 memset(&stat, 0, sizeof(stat)); 236 stat.max = INT_MAX; 237 stat.name = stub_name; 238 stat.perf = 1; 239 t0 = ktime_get_ns(); 240 kallsyms_on_each_symbol(find_symbol, &stat); 241 t1 = ktime_get_ns(); 242 pr_info("kallsyms_on_each_symbol() traverse all: %lld ns\n", t1 - t0); 243 } 244 245 static int match_symbol(void *data, unsigned long addr) 246 { 247 struct test_stat *stat = (struct test_stat *)data; 248 249 stat->real_cnt++; 250 stat->addr = addr; 251 252 if (stat->save_cnt < MAX_NUM_OF_RECORDS) { 253 stat->addrs[stat->save_cnt] = addr; 254 stat->save_cnt++; 255 } 256 257 if (stat->real_cnt == stat->max) 258 return 1; 259 260 return 0; 261 } 262 263 static void test_perf_kallsyms_on_each_match_symbol(void) 264 { 265 u64 t0, t1; 266 struct test_stat stat; 267 268 memset(&stat, 0, sizeof(stat)); 269 stat.max = INT_MAX; 270 stat.name = stub_name; 271 t0 = ktime_get_ns(); 272 kallsyms_on_each_match_symbol(match_symbol, stat.name, &stat); 273 t1 = ktime_get_ns(); 274 pr_info("kallsyms_on_each_match_symbol() traverse all: %lld ns\n", t1 - t0); 275 } 276 277 static int test_kallsyms_basic_function(void) 278 { 279 int i, j, ret; 280 int next = 0, nr_failed = 0; 281 char *prefix; 282 unsigned short rand; 283 unsigned long addr, lookup_addr; 284 char namebuf[KSYM_NAME_LEN]; 285 struct test_stat *stat, *stat2; 286 287 stat = kmalloc(sizeof(*stat) * 2, GFP_KERNEL); 288 if (!stat) 289 return -ENOMEM; 290 stat2 = stat + 1; 291 292 prefix = "kallsyms_lookup_name() for"; 293 for (i = 0; i < ARRAY_SIZE(test_items); i++) { 294 addr = kallsyms_lookup_name(test_items[i].name); 295 if (addr != test_items[i].addr) { 296 nr_failed++; 297 pr_info("%s %s failed: addr=%lx, expect %lx\n", 298 prefix, test_items[i].name, addr, test_items[i].addr); 299 } 300 } 301 302 prefix = "kallsyms_on_each_symbol() for"; 303 for (i = 0; i < ARRAY_SIZE(test_items); i++) { 304 memset(stat, 0, sizeof(*stat)); 305 stat->max = INT_MAX; 306 stat->name = test_items[i].name; 307 kallsyms_on_each_symbol(find_symbol, stat); 308 if (stat->addr != test_items[i].addr || stat->real_cnt != 1) { 309 nr_failed++; 310 pr_info("%s %s failed: count=%d, addr=%lx, expect %lx\n", 311 prefix, test_items[i].name, 312 stat->real_cnt, stat->addr, test_items[i].addr); 313 } 314 } 315 316 prefix = "kallsyms_on_each_match_symbol() for"; 317 for (i = 0; i < ARRAY_SIZE(test_items); i++) { 318 memset(stat, 0, sizeof(*stat)); 319 stat->max = INT_MAX; 320 stat->name = test_items[i].name; 321 kallsyms_on_each_match_symbol(match_symbol, test_items[i].name, stat); 322 if (stat->addr != test_items[i].addr || stat->real_cnt != 1) { 323 nr_failed++; 324 pr_info("%s %s failed: count=%d, addr=%lx, expect %lx\n", 325 prefix, test_items[i].name, 326 stat->real_cnt, stat->addr, test_items[i].addr); 327 } 328 } 329 330 if (nr_failed) { 331 kfree(stat); 332 return -ESRCH; 333 } 334 335 for (i = 0; i < kallsyms_num_syms; i++) { 336 addr = kallsyms_sym_address(i); 337 if (!is_ksym_addr(addr)) 338 continue; 339 340 ret = lookup_symbol_name(addr, namebuf); 341 if (unlikely(ret)) { 342 namebuf[0] = 0; 343 pr_info("%d: lookup_symbol_name(%lx) failed\n", i, addr); 344 goto failed; 345 } 346 347 lookup_addr = kallsyms_lookup_name(namebuf); 348 349 memset(stat, 0, sizeof(*stat)); 350 stat->max = INT_MAX; 351 kallsyms_on_each_match_symbol(match_symbol, namebuf, stat); 352 353 /* 354 * kallsyms_on_each_symbol() is too slow, randomly select some 355 * symbols for test. 356 */ 357 if (i >= next) { 358 memset(stat2, 0, sizeof(*stat2)); 359 stat2->max = INT_MAX; 360 stat2->name = namebuf; 361 kallsyms_on_each_symbol(find_symbol, stat2); 362 363 /* 364 * kallsyms_on_each_symbol() and kallsyms_on_each_match_symbol() 365 * need to get the same traversal result. 366 */ 367 if (stat->addr != stat2->addr || 368 stat->real_cnt != stat2->real_cnt || 369 memcmp(stat->addrs, stat2->addrs, 370 stat->save_cnt * sizeof(stat->addrs[0]))) { 371 pr_info("%s: mismatch between kallsyms_on_each_symbol() and kallsyms_on_each_match_symbol()\n", 372 namebuf); 373 goto failed; 374 } 375 376 /* 377 * The average of random increments is 128, that is, one of 378 * them is tested every 128 symbols. 379 */ 380 get_random_bytes(&rand, sizeof(rand)); 381 next = i + (rand & 0xff) + 1; 382 } 383 384 /* Need to be found at least once */ 385 if (!stat->real_cnt) { 386 pr_info("%s: Never found\n", namebuf); 387 goto failed; 388 } 389 390 /* 391 * kallsyms_lookup_name() returns the address of the first 392 * symbol found and cannot be NULL. 393 */ 394 if (!lookup_addr) { 395 pr_info("%s: NULL lookup_addr?!\n", namebuf); 396 goto failed; 397 } 398 if (lookup_addr != stat->addrs[0]) { 399 pr_info("%s: lookup_addr != stat->addrs[0]\n", namebuf); 400 goto failed; 401 } 402 403 /* 404 * If the addresses of all matching symbols are recorded, the 405 * target address needs to be exist. 406 */ 407 if (stat->real_cnt <= MAX_NUM_OF_RECORDS) { 408 for (j = 0; j < stat->save_cnt; j++) { 409 if (stat->addrs[j] == addr) 410 break; 411 } 412 413 if (j == stat->save_cnt) { 414 pr_info("%s: j == save_cnt?!\n", namebuf); 415 goto failed; 416 } 417 } 418 } 419 420 kfree(stat); 421 422 return 0; 423 424 failed: 425 pr_info("Test for %dth symbol failed: (%s) addr=%lx", i, namebuf, addr); 426 kfree(stat); 427 return -ESRCH; 428 } 429 430 static int test_entry(void *p) 431 { 432 int ret; 433 434 do { 435 schedule_timeout(5 * HZ); 436 } while (system_state != SYSTEM_RUNNING); 437 438 pr_info("start\n"); 439 ret = test_kallsyms_basic_function(); 440 if (ret) { 441 pr_info("abort\n"); 442 return 0; 443 } 444 445 test_kallsyms_compression_ratio(); 446 test_perf_kallsyms_lookup_name(); 447 test_perf_kallsyms_on_each_symbol(); 448 test_perf_kallsyms_on_each_match_symbol(); 449 pr_info("finish\n"); 450 451 return 0; 452 } 453 454 static int __init kallsyms_test_init(void) 455 { 456 struct task_struct *t; 457 458 t = kthread_create(test_entry, NULL, "kallsyms_test"); 459 if (IS_ERR(t)) { 460 pr_info("Create kallsyms selftest task failed\n"); 461 return PTR_ERR(t); 462 } 463 kthread_bind(t, 0); 464 wake_up_process(t); 465 466 return 0; 467 } 468 late_initcall(kallsyms_test_init); 469