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) kallsyms_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 ".LASANPC", /* s390 kasan local symbols */ 47 "__crc_", /* modversions */ 48 "__efistub_", /* arm64 EFI stub namespace */ 49 "__kvm_nvhe_", /* arm64 non-VHE KVM namespace */ 50 "__AArch64ADRPThunk_", /* arm64 lld */ 51 "__ARMV5PILongThunk_", /* arm lld */ 52 "__ARMV7PILongThunk_", 53 "__ThumbV7PILongThunk_", 54 "__LA25Thunk_", /* mips lld */ 55 "__microLA25Thunk_", 56 NULL 57 }; 58 59 /* Symbol names that end with the following are ignored.*/ 60 static const char * const ignored_suffixes[] = { 61 "_from_arm", /* arm */ 62 "_from_thumb", /* arm */ 63 "_veneer", /* arm */ 64 NULL 65 }; 66 67 /* Symbol names that contain the following are ignored.*/ 68 static const char * const ignored_matches[] = { 69 ".long_branch.", /* ppc stub */ 70 ".plt_branch.", /* ppc stub */ 71 NULL 72 }; 73 74 const char * const *p; 75 76 for (p = ignored_symbols; *p; p++) 77 if (!strcmp(name, *p)) 78 return true; 79 80 for (p = ignored_prefixes; *p; p++) 81 if (!strncmp(name, *p, strlen(*p))) 82 return true; 83 84 for (p = ignored_suffixes; *p; p++) { 85 int l = strlen(name) - strlen(*p); 86 87 if (l >= 0 && !strcmp(name + l, *p)) 88 return true; 89 } 90 91 for (p = ignored_matches; *p; p++) { 92 if (strstr(name, *p)) 93 return true; 94 } 95 96 if (type == 'U' || type == 'u') 97 return true; 98 /* exclude debugging symbols */ 99 if (type == 'N' || type == 'n') 100 return true; 101 102 if (toupper(type) == 'A') { 103 /* Keep these useful absolute symbols */ 104 if (strcmp(name, "__kernel_syscall_via_break") && 105 strcmp(name, "__kernel_syscall_via_epc") && 106 strcmp(name, "__kernel_sigtramp") && 107 strcmp(name, "__gp")) 108 return true; 109 } 110 111 return false; 112 } 113 114 static int test__vmlinux_matches_kallsyms(struct test_suite *test __maybe_unused, 115 int subtest __maybe_unused) 116 { 117 int err = TEST_FAIL; 118 struct rb_node *nd; 119 struct symbol *sym; 120 struct map *kallsyms_map, *vmlinux_map, *map; 121 struct machine kallsyms, vmlinux; 122 struct maps *maps; 123 u64 mem_start, mem_end; 124 bool header_printed; 125 126 /* 127 * Step 1: 128 * 129 * Init the machines that will hold kernel, modules obtained from 130 * both vmlinux + .ko files and from /proc/kallsyms split by modules. 131 */ 132 machine__init(&kallsyms, "", HOST_KERNEL_ID); 133 machine__init(&vmlinux, "", HOST_KERNEL_ID); 134 135 maps = machine__kernel_maps(&vmlinux); 136 137 /* 138 * Step 2: 139 * 140 * Create the kernel maps for kallsyms and the DSO where we will then 141 * load /proc/kallsyms. Also create the modules maps from /proc/modules 142 * and find the .ko files that match them in /lib/modules/`uname -r`/. 143 */ 144 if (machine__create_kernel_maps(&kallsyms) < 0) { 145 pr_debug("machine__create_kernel_maps failed"); 146 err = TEST_SKIP; 147 goto out; 148 } 149 150 /* 151 * Step 3: 152 * 153 * Load and split /proc/kallsyms into multiple maps, one per module. 154 * Do not use kcore, as this test was designed before kcore support 155 * and has parts that only make sense if using the non-kcore code. 156 * XXX: extend it to stress the kcorre code as well, hint: the list 157 * of modules extracted from /proc/kcore, in its current form, can't 158 * be compacted against the list of modules found in the "vmlinux" 159 * code and with the one got from /proc/modules from the "kallsyms" code. 160 */ 161 if (machine__load_kallsyms(&kallsyms, "/proc/kallsyms") <= 0) { 162 pr_debug("machine__load_kallsyms failed"); 163 err = TEST_SKIP; 164 goto out; 165 } 166 167 /* 168 * Step 4: 169 * 170 * kallsyms will be internally on demand sorted by name so that we can 171 * find the reference relocation * symbol, i.e. the symbol we will use 172 * to see if the running kernel was relocated by checking if it has the 173 * same value in the vmlinux file we load. 174 */ 175 kallsyms_map = machine__kernel_map(&kallsyms); 176 177 /* 178 * Step 5: 179 * 180 * Now repeat step 2, this time for the vmlinux file we'll auto-locate. 181 */ 182 if (machine__create_kernel_maps(&vmlinux) < 0) { 183 pr_info("machine__create_kernel_maps failed"); 184 goto out; 185 } 186 187 vmlinux_map = machine__kernel_map(&vmlinux); 188 189 /* 190 * Step 6: 191 * 192 * Locate a vmlinux file in the vmlinux path that has a buildid that 193 * matches the one of the running kernel. 194 * 195 * While doing that look if we find the ref reloc symbol, if we find it 196 * we'll have its ref_reloc_symbol.unrelocated_addr and then 197 * maps__reloc_vmlinux will notice and set proper ->[un]map_ip routines 198 * to fixup the symbols. 199 */ 200 if (machine__load_vmlinux_path(&vmlinux) <= 0) { 201 pr_info("Couldn't find a vmlinux that matches the kernel running on this machine, skipping test\n"); 202 err = TEST_SKIP; 203 goto out; 204 } 205 206 err = 0; 207 /* 208 * Step 7: 209 * 210 * Now look at the symbols in the vmlinux DSO and check if we find all of them 211 * in the kallsyms dso. For the ones that are in both, check its names and 212 * end addresses too. 213 */ 214 map__for_each_symbol(vmlinux_map, sym, nd) { 215 struct symbol *pair, *first_pair; 216 217 sym = rb_entry(nd, struct symbol, rb_node); 218 219 if (sym->start == sym->end) 220 continue; 221 222 mem_start = vmlinux_map->unmap_ip(vmlinux_map, sym->start); 223 mem_end = vmlinux_map->unmap_ip(vmlinux_map, sym->end); 224 225 first_pair = machine__find_kernel_symbol(&kallsyms, mem_start, NULL); 226 pair = first_pair; 227 228 if (pair && UM(pair->start) == mem_start) { 229 next_pair: 230 if (arch__compare_symbol_names(sym->name, pair->name) == 0) { 231 /* 232 * kallsyms don't have the symbol end, so we 233 * set that by using the next symbol start - 1, 234 * in some cases we get this up to a page 235 * wrong, trace_kmalloc when I was developing 236 * this code was one such example, 2106 bytes 237 * off the real size. More than that and we 238 * _really_ have a problem. 239 */ 240 s64 skew = mem_end - UM(pair->end); 241 if (llabs(skew) >= page_size) 242 pr_debug("WARN: %#" PRIx64 ": diff end addr for %s v: %#" PRIx64 " k: %#" PRIx64 "\n", 243 mem_start, sym->name, mem_end, 244 UM(pair->end)); 245 246 /* 247 * Do not count this as a failure, because we 248 * could really find a case where it's not 249 * possible to get proper function end from 250 * kallsyms. 251 */ 252 continue; 253 } else { 254 pair = machine__find_kernel_symbol_by_name(&kallsyms, sym->name, NULL); 255 if (pair) { 256 if (UM(pair->start) == mem_start) 257 goto next_pair; 258 259 pr_debug("WARN: %#" PRIx64 ": diff name v: %s k: %s\n", 260 mem_start, sym->name, pair->name); 261 } else { 262 pr_debug("WARN: %#" PRIx64 ": diff name v: %s k: %s\n", 263 mem_start, sym->name, first_pair->name); 264 } 265 266 continue; 267 } 268 } else if (mem_start == kallsyms.vmlinux_map->end) { 269 /* 270 * Ignore aliases to _etext, i.e. to the end of the kernel text area, 271 * such as __indirect_thunk_end. 272 */ 273 continue; 274 } else if (is_ignored_symbol(sym->name, sym->type)) { 275 /* 276 * Ignore hidden symbols, see scripts/kallsyms.c for the details 277 */ 278 continue; 279 } else { 280 pr_debug("ERR : %#" PRIx64 ": %s not on kallsyms\n", 281 mem_start, sym->name); 282 } 283 284 err = -1; 285 } 286 287 if (verbose <= 0) 288 goto out; 289 290 header_printed = false; 291 292 maps__for_each_entry(maps, map) { 293 struct map * 294 /* 295 * If it is the kernel, kallsyms is always "[kernel.kallsyms]", while 296 * the kernel will have the path for the vmlinux file being used, 297 * so use the short name, less descriptive but the same ("[kernel]" in 298 * both cases. 299 */ 300 pair = maps__find_by_name(kallsyms.kmaps, (map->dso->kernel ? 301 map->dso->short_name : 302 map->dso->name)); 303 if (pair) { 304 pair->priv = 1; 305 } else { 306 if (!header_printed) { 307 pr_info("WARN: Maps only in vmlinux:\n"); 308 header_printed = true; 309 } 310 map__fprintf(map, stderr); 311 } 312 } 313 314 header_printed = false; 315 316 maps__for_each_entry(maps, map) { 317 struct map *pair; 318 319 mem_start = vmlinux_map->unmap_ip(vmlinux_map, map->start); 320 mem_end = vmlinux_map->unmap_ip(vmlinux_map, map->end); 321 322 pair = maps__find(kallsyms.kmaps, mem_start); 323 if (pair == NULL || pair->priv) 324 continue; 325 326 if (pair->start == mem_start) { 327 if (!header_printed) { 328 pr_info("WARN: Maps in vmlinux with a different name in kallsyms:\n"); 329 header_printed = true; 330 } 331 332 pr_info("WARN: %" PRIx64 "-%" PRIx64 " %" PRIx64 " %s in kallsyms as", 333 map->start, map->end, map->pgoff, map->dso->name); 334 if (mem_end != pair->end) 335 pr_info(":\nWARN: *%" PRIx64 "-%" PRIx64 " %" PRIx64, 336 pair->start, pair->end, pair->pgoff); 337 pr_info(" %s\n", pair->dso->name); 338 pair->priv = 1; 339 } 340 } 341 342 header_printed = false; 343 344 maps = machine__kernel_maps(&kallsyms); 345 346 maps__for_each_entry(maps, map) { 347 if (!map->priv) { 348 if (!header_printed) { 349 pr_info("WARN: Maps only in kallsyms:\n"); 350 header_printed = true; 351 } 352 map__fprintf(map, stderr); 353 } 354 } 355 out: 356 machine__exit(&kallsyms); 357 machine__exit(&vmlinux); 358 return err; 359 } 360 361 DEFINE_SUITE("vmlinux symtab matches kallsyms", vmlinux_matches_kallsyms); 362