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