1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/compiler.h> 3 #include <linux/rbtree.h> 4 #include <inttypes.h> 5 #include <string.h> 6 #include <ctype.h> 7 #include <stdlib.h> 8 #include "dso.h" 9 #include "map.h" 10 #include "symbol.h" 11 #include <internal/lib.h> // page_size 12 #include "tests.h" 13 #include "debug.h" 14 #include "machine.h" 15 16 #define UM(x) map__unmap_ip(kallsyms_map, (x)) 17 18 static bool is_ignored_symbol(const char *name, char type) 19 { 20 /* Symbol names that exactly match to the following are ignored.*/ 21 static const char * const ignored_symbols[] = { 22 /* 23 * Symbols which vary between passes. Passes 1 and 2 must have 24 * identical symbol lists. The kallsyms_* symbols below are 25 * only added after pass 1, they would be included in pass 2 26 * when --all-symbols is specified so exclude them to get a 27 * stable symbol list. 28 */ 29 "kallsyms_offsets", 30 "kallsyms_num_syms", 31 "kallsyms_names", 32 "kallsyms_markers", 33 "kallsyms_token_table", 34 "kallsyms_token_index", 35 /* Exclude linker generated symbols which vary between passes */ 36 "_SDA_BASE_", /* ppc */ 37 "_SDA2_BASE_", /* ppc */ 38 NULL 39 }; 40 41 /* Symbol names that begin with the following are ignored.*/ 42 static const char * const ignored_prefixes[] = { 43 "$", /* local symbols for ARM, MIPS, etc. */ 44 ".L", /* local labels, .LBB,.Ltmpxxx,.L__unnamed_xx,.LASANPC, etc. */ 45 "__crc_", /* modversions */ 46 "__efistub_", /* arm64 EFI stub namespace */ 47 "__kvm_nvhe_$", /* arm64 local symbols in non-VHE KVM namespace */ 48 "__kvm_nvhe_.L", /* arm64 local symbols in non-VHE KVM namespace */ 49 "__AArch64ADRPThunk_", /* arm64 lld */ 50 "__ARMV5PILongThunk_", /* arm lld */ 51 "__ARMV7PILongThunk_", 52 "__ThumbV7PILongThunk_", 53 "__LA25Thunk_", /* mips lld */ 54 "__microLA25Thunk_", 55 NULL 56 }; 57 58 /* Symbol names that end with the following are ignored.*/ 59 static const char * const ignored_suffixes[] = { 60 "_from_arm", /* arm */ 61 "_from_thumb", /* arm */ 62 "_veneer", /* arm */ 63 NULL 64 }; 65 66 /* Symbol names that contain the following are ignored.*/ 67 static const char * const ignored_matches[] = { 68 ".long_branch.", /* ppc stub */ 69 ".plt_branch.", /* ppc stub */ 70 NULL 71 }; 72 73 const char * const *p; 74 75 for (p = ignored_symbols; *p; p++) 76 if (!strcmp(name, *p)) 77 return true; 78 79 for (p = ignored_prefixes; *p; p++) 80 if (!strncmp(name, *p, strlen(*p))) 81 return true; 82 83 for (p = ignored_suffixes; *p; p++) { 84 int l = strlen(name) - strlen(*p); 85 86 if (l >= 0 && !strcmp(name + l, *p)) 87 return true; 88 } 89 90 for (p = ignored_matches; *p; p++) { 91 if (strstr(name, *p)) 92 return true; 93 } 94 95 if (type == 'U' || type == 'u') 96 return true; 97 /* exclude debugging symbols */ 98 if (type == 'N' || type == 'n') 99 return true; 100 101 if (toupper(type) == 'A') { 102 /* Keep these useful absolute symbols */ 103 if (strcmp(name, "__kernel_syscall_via_break") && 104 strcmp(name, "__kernel_syscall_via_epc") && 105 strcmp(name, "__kernel_sigtramp") && 106 strcmp(name, "__gp")) 107 return true; 108 } 109 110 return false; 111 } 112 113 struct test__vmlinux_matches_kallsyms_cb_args { 114 struct machine kallsyms; 115 struct map *vmlinux_map; 116 bool header_printed; 117 }; 118 119 static int test__vmlinux_matches_kallsyms_cb1(struct map *map, void *data) 120 { 121 struct test__vmlinux_matches_kallsyms_cb_args *args = data; 122 struct dso *dso = map__dso(map); 123 /* 124 * If it is the kernel, kallsyms is always "[kernel.kallsyms]", while 125 * the kernel will have the path for the vmlinux file being used, so use 126 * the short name, less descriptive but the same ("[kernel]" in both 127 * cases. 128 */ 129 struct map *pair = maps__find_by_name(args->kallsyms.kmaps, 130 (dso__kernel(dso) ? dso__short_name(dso) : dso__name(dso))); 131 132 if (pair) { 133 map__set_priv(pair); 134 map__put(pair); 135 } else { 136 if (!args->header_printed) { 137 pr_info("WARN: Maps only in vmlinux:\n"); 138 args->header_printed = true; 139 } 140 map__fprintf(map, stderr); 141 } 142 return 0; 143 } 144 145 static int test__vmlinux_matches_kallsyms_cb2(struct map *map, void *data) 146 { 147 struct test__vmlinux_matches_kallsyms_cb_args *args = data; 148 struct map *pair; 149 u64 mem_start = map__unmap_ip(args->vmlinux_map, map__start(map)); 150 u64 mem_end = map__unmap_ip(args->vmlinux_map, map__end(map)); 151 152 pair = maps__find(args->kallsyms.kmaps, mem_start); 153 154 if (pair != NULL && !map__priv(pair) && map__start(pair) == mem_start) { 155 struct dso *dso = map__dso(map); 156 157 if (!args->header_printed) { 158 pr_info("WARN: Maps in vmlinux with a different name in kallsyms:\n"); 159 args->header_printed = true; 160 } 161 162 pr_info("WARN: %" PRIx64 "-%" PRIx64 " %" PRIx64 " %s in kallsyms as", 163 map__start(map), map__end(map), map__pgoff(map), dso__name(dso)); 164 if (mem_end != map__end(pair)) 165 pr_info(":\nWARN: *%" PRIx64 "-%" PRIx64 " %" PRIx64, 166 map__start(pair), map__end(pair), map__pgoff(pair)); 167 pr_info(" %s\n", dso__name(dso)); 168 map__set_priv(pair); 169 } 170 map__put(pair); 171 return 0; 172 } 173 174 static int test__vmlinux_matches_kallsyms_cb3(struct map *map, void *data) 175 { 176 struct test__vmlinux_matches_kallsyms_cb_args *args = data; 177 178 if (!map__priv(map)) { 179 if (!args->header_printed) { 180 pr_info("WARN: Maps only in kallsyms:\n"); 181 args->header_printed = true; 182 } 183 map__fprintf(map, stderr); 184 } 185 return 0; 186 } 187 188 static int test__vmlinux_matches_kallsyms(struct test_suite *test __maybe_unused, 189 int subtest __maybe_unused) 190 { 191 int err = TEST_FAIL; 192 struct rb_node *nd; 193 struct symbol *sym; 194 struct map *kallsyms_map; 195 struct machine vmlinux = { 0 }; 196 struct maps *maps; 197 u64 mem_start, mem_end; 198 struct test__vmlinux_matches_kallsyms_cb_args args; 199 200 /* 201 * Step 1: 202 * 203 * Init the machines that will hold kernel, modules obtained from 204 * both vmlinux + .ko files and from /proc/kallsyms split by modules. 205 */ 206 if (machine__init(&args.kallsyms, "", HOST_KERNEL_ID)) 207 goto out; 208 if (machine__init(&vmlinux, "", HOST_KERNEL_ID)) 209 goto out; 210 211 maps = machine__kernel_maps(&vmlinux); 212 213 /* 214 * Step 2: 215 * 216 * Create the kernel maps for kallsyms and the DSO where we will then 217 * load /proc/kallsyms. Also create the modules maps from /proc/modules 218 * and find the .ko files that match them in /lib/modules/`uname -r`/. 219 */ 220 if (machine__create_kernel_maps(&args.kallsyms) < 0) { 221 pr_debug("machine__create_kernel_maps failed"); 222 err = TEST_SKIP; 223 goto out; 224 } 225 226 /* 227 * Step 3: 228 * 229 * Load and split /proc/kallsyms into multiple maps, one per module. 230 * Do not use kcore, as this test was designed before kcore support 231 * and has parts that only make sense if using the non-kcore code. 232 * XXX: extend it to stress the kcorre code as well, hint: the list 233 * of modules extracted from /proc/kcore, in its current form, can't 234 * be compacted against the list of modules found in the "vmlinux" 235 * code and with the one got from /proc/modules from the "kallsyms" code. 236 */ 237 if (machine__load_kallsyms(&args.kallsyms, "/proc/kallsyms") <= 0) { 238 pr_debug("machine__load_kallsyms failed"); 239 err = TEST_SKIP; 240 goto out; 241 } 242 243 /* 244 * Step 4: 245 * 246 * kallsyms will be internally on demand sorted by name so that we can 247 * find the reference relocation * symbol, i.e. the symbol we will use 248 * to see if the running kernel was relocated by checking if it has the 249 * same value in the vmlinux file we load. 250 */ 251 kallsyms_map = machine__kernel_map(&args.kallsyms); 252 253 /* 254 * Step 5: 255 * 256 * Now repeat step 2, this time for the vmlinux file we'll auto-locate. 257 */ 258 if (machine__create_kernel_maps(&vmlinux) < 0) { 259 pr_info("machine__create_kernel_maps failed"); 260 goto out; 261 } 262 263 args.vmlinux_map = machine__kernel_map(&vmlinux); 264 265 /* 266 * Step 6: 267 * 268 * Locate a vmlinux file in the vmlinux path that has a buildid that 269 * matches the one of the running kernel. 270 * 271 * While doing that look if we find the ref reloc symbol, if we find it 272 * we'll have its ref_reloc_symbol.unrelocated_addr and then 273 * maps__reloc_vmlinux will notice and set proper ->[un]map_ip routines 274 * to fixup the symbols. 275 */ 276 if (machine__load_vmlinux_path(&vmlinux) <= 0) { 277 pr_info("Couldn't find a vmlinux that matches the kernel running on this machine, skipping test\n"); 278 err = TEST_SKIP; 279 goto out; 280 } 281 282 err = 0; 283 /* 284 * Step 7: 285 * 286 * Now look at the symbols in the vmlinux DSO and check if we find all of them 287 * in the kallsyms dso. For the ones that are in both, check its names and 288 * end addresses too. 289 */ 290 map__for_each_symbol(args.vmlinux_map, sym, nd) { 291 struct symbol *pair, *first_pair; 292 293 sym = rb_entry(nd, struct symbol, rb_node); 294 295 if (sym->start == sym->end) 296 continue; 297 298 mem_start = map__unmap_ip(args.vmlinux_map, sym->start); 299 mem_end = map__unmap_ip(args.vmlinux_map, sym->end); 300 301 first_pair = machine__find_kernel_symbol(&args.kallsyms, mem_start, NULL); 302 pair = first_pair; 303 304 if (pair && UM(pair->start) == mem_start) { 305 next_pair: 306 if (arch__compare_symbol_names(sym->name, pair->name) == 0) { 307 /* 308 * kallsyms don't have the symbol end, so we 309 * set that by using the next symbol start - 1, 310 * in some cases we get this up to a page 311 * wrong, trace_kmalloc when I was developing 312 * this code was one such example, 2106 bytes 313 * off the real size. More than that and we 314 * _really_ have a problem. 315 */ 316 s64 skew = mem_end - UM(pair->end); 317 if (llabs(skew) >= page_size) 318 pr_debug("WARN: %#" PRIx64 ": diff end addr for %s v: %#" PRIx64 " k: %#" PRIx64 "\n", 319 mem_start, sym->name, mem_end, 320 UM(pair->end)); 321 322 /* 323 * Do not count this as a failure, because we 324 * could really find a case where it's not 325 * possible to get proper function end from 326 * kallsyms. 327 */ 328 continue; 329 } else { 330 pair = machine__find_kernel_symbol_by_name(&args.kallsyms, 331 sym->name, NULL); 332 if (pair) { 333 if (UM(pair->start) == mem_start) 334 goto next_pair; 335 336 pr_debug("WARN: %#" PRIx64 ": diff name v: %s k: %s\n", 337 mem_start, sym->name, pair->name); 338 } else { 339 pr_debug("WARN: %#" PRIx64 ": diff name v: %s k: %s\n", 340 mem_start, sym->name, first_pair->name); 341 } 342 343 continue; 344 } 345 } else if (mem_start == map__end(args.kallsyms.vmlinux_map)) { 346 /* 347 * Ignore aliases to _etext, i.e. to the end of the kernel text area, 348 * such as __indirect_thunk_end. 349 */ 350 continue; 351 } else if (is_ignored_symbol(sym->name, symbol__type(sym))) { 352 /* 353 * Ignore hidden symbols, see scripts/kallsyms.c for the details 354 */ 355 continue; 356 } else { 357 pr_debug("ERR : %#" PRIx64 ": %s not on kallsyms\n", 358 mem_start, sym->name); 359 } 360 361 err = -1; 362 } 363 364 if (verbose <= 0) 365 goto out; 366 367 args.header_printed = false; 368 maps__for_each_map(maps, test__vmlinux_matches_kallsyms_cb1, &args); 369 370 args.header_printed = false; 371 maps__for_each_map(maps, test__vmlinux_matches_kallsyms_cb2, &args); 372 373 args.header_printed = false; 374 maps = machine__kernel_maps(&args.kallsyms); 375 maps__for_each_map(maps, test__vmlinux_matches_kallsyms_cb3, &args); 376 377 out: 378 machine__exit(&args.kallsyms); 379 machine__exit(&vmlinux); 380 return err; 381 } 382 383 DEFINE_SUITE("vmlinux symtab matches kallsyms", vmlinux_matches_kallsyms); 384