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 "$", /* local symbols for ARM, MIPS, etc. */ 46 ".L", /* local labels, .LBB,.Ltmpxxx,.L__unnamed_xx,.LASANPC, etc. */ 47 "__crc_", /* modversions */ 48 "__efistub_", /* arm64 EFI stub namespace */ 49 "__kvm_nvhe_$", /* 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, *map; 122 struct machine kallsyms, vmlinux; 123 struct maps *maps; 124 u64 mem_start, mem_end; 125 bool header_printed; 126 127 /* 128 * Step 1: 129 * 130 * Init the machines that will hold kernel, modules obtained from 131 * both vmlinux + .ko files and from /proc/kallsyms split by modules. 132 */ 133 machine__init(&kallsyms, "", HOST_KERNEL_ID); 134 machine__init(&vmlinux, "", HOST_KERNEL_ID); 135 136 maps = machine__kernel_maps(&vmlinux); 137 138 /* 139 * Step 2: 140 * 141 * Create the kernel maps for kallsyms and the DSO where we will then 142 * load /proc/kallsyms. Also create the modules maps from /proc/modules 143 * and find the .ko files that match them in /lib/modules/`uname -r`/. 144 */ 145 if (machine__create_kernel_maps(&kallsyms) < 0) { 146 pr_debug("machine__create_kernel_maps failed"); 147 err = TEST_SKIP; 148 goto out; 149 } 150 151 /* 152 * Step 3: 153 * 154 * Load and split /proc/kallsyms into multiple maps, one per module. 155 * Do not use kcore, as this test was designed before kcore support 156 * and has parts that only make sense if using the non-kcore code. 157 * XXX: extend it to stress the kcorre code as well, hint: the list 158 * of modules extracted from /proc/kcore, in its current form, can't 159 * be compacted against the list of modules found in the "vmlinux" 160 * code and with the one got from /proc/modules from the "kallsyms" code. 161 */ 162 if (machine__load_kallsyms(&kallsyms, "/proc/kallsyms") <= 0) { 163 pr_debug("machine__load_kallsyms failed"); 164 err = TEST_SKIP; 165 goto out; 166 } 167 168 /* 169 * Step 4: 170 * 171 * kallsyms will be internally on demand sorted by name so that we can 172 * find the reference relocation * symbol, i.e. the symbol we will use 173 * to see if the running kernel was relocated by checking if it has the 174 * same value in the vmlinux file we load. 175 */ 176 kallsyms_map = machine__kernel_map(&kallsyms); 177 178 /* 179 * Step 5: 180 * 181 * Now repeat step 2, this time for the vmlinux file we'll auto-locate. 182 */ 183 if (machine__create_kernel_maps(&vmlinux) < 0) { 184 pr_info("machine__create_kernel_maps failed"); 185 goto out; 186 } 187 188 vmlinux_map = machine__kernel_map(&vmlinux); 189 190 /* 191 * Step 6: 192 * 193 * Locate a vmlinux file in the vmlinux path that has a buildid that 194 * matches the one of the running kernel. 195 * 196 * While doing that look if we find the ref reloc symbol, if we find it 197 * we'll have its ref_reloc_symbol.unrelocated_addr and then 198 * maps__reloc_vmlinux will notice and set proper ->[un]map_ip routines 199 * to fixup the symbols. 200 */ 201 if (machine__load_vmlinux_path(&vmlinux) <= 0) { 202 pr_info("Couldn't find a vmlinux that matches the kernel running on this machine, skipping test\n"); 203 err = TEST_SKIP; 204 goto out; 205 } 206 207 err = 0; 208 /* 209 * Step 7: 210 * 211 * Now look at the symbols in the vmlinux DSO and check if we find all of them 212 * in the kallsyms dso. For the ones that are in both, check its names and 213 * end addresses too. 214 */ 215 map__for_each_symbol(vmlinux_map, sym, nd) { 216 struct symbol *pair, *first_pair; 217 218 sym = rb_entry(nd, struct symbol, rb_node); 219 220 if (sym->start == sym->end) 221 continue; 222 223 mem_start = vmlinux_map->unmap_ip(vmlinux_map, sym->start); 224 mem_end = vmlinux_map->unmap_ip(vmlinux_map, sym->end); 225 226 first_pair = machine__find_kernel_symbol(&kallsyms, mem_start, NULL); 227 pair = first_pair; 228 229 if (pair && UM(pair->start) == mem_start) { 230 next_pair: 231 if (arch__compare_symbol_names(sym->name, pair->name) == 0) { 232 /* 233 * kallsyms don't have the symbol end, so we 234 * set that by using the next symbol start - 1, 235 * in some cases we get this up to a page 236 * wrong, trace_kmalloc when I was developing 237 * this code was one such example, 2106 bytes 238 * off the real size. More than that and we 239 * _really_ have a problem. 240 */ 241 s64 skew = mem_end - UM(pair->end); 242 if (llabs(skew) >= page_size) 243 pr_debug("WARN: %#" PRIx64 ": diff end addr for %s v: %#" PRIx64 " k: %#" PRIx64 "\n", 244 mem_start, sym->name, mem_end, 245 UM(pair->end)); 246 247 /* 248 * Do not count this as a failure, because we 249 * could really find a case where it's not 250 * possible to get proper function end from 251 * kallsyms. 252 */ 253 continue; 254 } else { 255 pair = machine__find_kernel_symbol_by_name(&kallsyms, sym->name, NULL); 256 if (pair) { 257 if (UM(pair->start) == mem_start) 258 goto next_pair; 259 260 pr_debug("WARN: %#" PRIx64 ": diff name v: %s k: %s\n", 261 mem_start, sym->name, pair->name); 262 } else { 263 pr_debug("WARN: %#" PRIx64 ": diff name v: %s k: %s\n", 264 mem_start, sym->name, first_pair->name); 265 } 266 267 continue; 268 } 269 } else if (mem_start == kallsyms.vmlinux_map->end) { 270 /* 271 * Ignore aliases to _etext, i.e. to the end of the kernel text area, 272 * such as __indirect_thunk_end. 273 */ 274 continue; 275 } else if (is_ignored_symbol(sym->name, sym->type)) { 276 /* 277 * Ignore hidden symbols, see scripts/kallsyms.c for the details 278 */ 279 continue; 280 } else { 281 pr_debug("ERR : %#" PRIx64 ": %s not on kallsyms\n", 282 mem_start, sym->name); 283 } 284 285 err = -1; 286 } 287 288 if (verbose <= 0) 289 goto out; 290 291 header_printed = false; 292 293 maps__for_each_entry(maps, map) { 294 struct map * 295 /* 296 * If it is the kernel, kallsyms is always "[kernel.kallsyms]", while 297 * the kernel will have the path for the vmlinux file being used, 298 * so use the short name, less descriptive but the same ("[kernel]" in 299 * both cases. 300 */ 301 pair = maps__find_by_name(kallsyms.kmaps, (map->dso->kernel ? 302 map->dso->short_name : 303 map->dso->name)); 304 if (pair) { 305 pair->priv = 1; 306 } else { 307 if (!header_printed) { 308 pr_info("WARN: Maps only in vmlinux:\n"); 309 header_printed = true; 310 } 311 map__fprintf(map, stderr); 312 } 313 } 314 315 header_printed = false; 316 317 maps__for_each_entry(maps, map) { 318 struct map *pair; 319 320 mem_start = vmlinux_map->unmap_ip(vmlinux_map, map->start); 321 mem_end = vmlinux_map->unmap_ip(vmlinux_map, map->end); 322 323 pair = maps__find(kallsyms.kmaps, mem_start); 324 if (pair == NULL || pair->priv) 325 continue; 326 327 if (pair->start == mem_start) { 328 if (!header_printed) { 329 pr_info("WARN: Maps in vmlinux with a different name in kallsyms:\n"); 330 header_printed = true; 331 } 332 333 pr_info("WARN: %" PRIx64 "-%" PRIx64 " %" PRIx64 " %s in kallsyms as", 334 map->start, map->end, map->pgoff, map->dso->name); 335 if (mem_end != pair->end) 336 pr_info(":\nWARN: *%" PRIx64 "-%" PRIx64 " %" PRIx64, 337 pair->start, pair->end, pair->pgoff); 338 pr_info(" %s\n", pair->dso->name); 339 pair->priv = 1; 340 } 341 } 342 343 header_printed = false; 344 345 maps = machine__kernel_maps(&kallsyms); 346 347 maps__for_each_entry(maps, map) { 348 if (!map->priv) { 349 if (!header_printed) { 350 pr_info("WARN: Maps only in kallsyms:\n"); 351 header_printed = true; 352 } 353 map__fprintf(map, stderr); 354 } 355 } 356 out: 357 machine__exit(&kallsyms); 358 machine__exit(&vmlinux); 359 return err; 360 } 361 362 DEFINE_SUITE("vmlinux symtab matches kallsyms", vmlinux_matches_kallsyms); 363