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