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
is_ignored_symbol(const char * name,char type)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
test__vmlinux_matches_kallsyms_cb1(struct map * map,void * data)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
test__vmlinux_matches_kallsyms_cb2(struct map * map,void * data)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
test__vmlinux_matches_kallsyms_cb3(struct map * map,void * data)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
test__vmlinux_matches_kallsyms(struct test_suite * test __maybe_unused,int subtest __maybe_unused)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;
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 machine__init(&args.kallsyms, "", HOST_KERNEL_ID);
207 machine__init(&vmlinux, "", HOST_KERNEL_ID);
208
209 maps = machine__kernel_maps(&vmlinux);
210
211 /*
212 * Step 2:
213 *
214 * Create the kernel maps for kallsyms and the DSO where we will then
215 * load /proc/kallsyms. Also create the modules maps from /proc/modules
216 * and find the .ko files that match them in /lib/modules/`uname -r`/.
217 */
218 if (machine__create_kernel_maps(&args.kallsyms) < 0) {
219 pr_debug("machine__create_kernel_maps failed");
220 err = TEST_SKIP;
221 goto out;
222 }
223
224 /*
225 * Step 3:
226 *
227 * Load and split /proc/kallsyms into multiple maps, one per module.
228 * Do not use kcore, as this test was designed before kcore support
229 * and has parts that only make sense if using the non-kcore code.
230 * XXX: extend it to stress the kcorre code as well, hint: the list
231 * of modules extracted from /proc/kcore, in its current form, can't
232 * be compacted against the list of modules found in the "vmlinux"
233 * code and with the one got from /proc/modules from the "kallsyms" code.
234 */
235 if (machine__load_kallsyms(&args.kallsyms, "/proc/kallsyms") <= 0) {
236 pr_debug("machine__load_kallsyms failed");
237 err = TEST_SKIP;
238 goto out;
239 }
240
241 /*
242 * Step 4:
243 *
244 * kallsyms will be internally on demand sorted by name so that we can
245 * find the reference relocation * symbol, i.e. the symbol we will use
246 * to see if the running kernel was relocated by checking if it has the
247 * same value in the vmlinux file we load.
248 */
249 kallsyms_map = machine__kernel_map(&args.kallsyms);
250
251 /*
252 * Step 5:
253 *
254 * Now repeat step 2, this time for the vmlinux file we'll auto-locate.
255 */
256 if (machine__create_kernel_maps(&vmlinux) < 0) {
257 pr_info("machine__create_kernel_maps failed");
258 goto out;
259 }
260
261 args.vmlinux_map = machine__kernel_map(&vmlinux);
262
263 /*
264 * Step 6:
265 *
266 * Locate a vmlinux file in the vmlinux path that has a buildid that
267 * matches the one of the running kernel.
268 *
269 * While doing that look if we find the ref reloc symbol, if we find it
270 * we'll have its ref_reloc_symbol.unrelocated_addr and then
271 * maps__reloc_vmlinux will notice and set proper ->[un]map_ip routines
272 * to fixup the symbols.
273 */
274 if (machine__load_vmlinux_path(&vmlinux) <= 0) {
275 pr_info("Couldn't find a vmlinux that matches the kernel running on this machine, skipping test\n");
276 err = TEST_SKIP;
277 goto out;
278 }
279
280 err = 0;
281 /*
282 * Step 7:
283 *
284 * Now look at the symbols in the vmlinux DSO and check if we find all of them
285 * in the kallsyms dso. For the ones that are in both, check its names and
286 * end addresses too.
287 */
288 map__for_each_symbol(args.vmlinux_map, sym, nd) {
289 struct symbol *pair, *first_pair;
290
291 sym = rb_entry(nd, struct symbol, rb_node);
292
293 if (sym->start == sym->end)
294 continue;
295
296 mem_start = map__unmap_ip(args.vmlinux_map, sym->start);
297 mem_end = map__unmap_ip(args.vmlinux_map, sym->end);
298
299 first_pair = machine__find_kernel_symbol(&args.kallsyms, mem_start, NULL);
300 pair = first_pair;
301
302 if (pair && UM(pair->start) == mem_start) {
303 next_pair:
304 if (arch__compare_symbol_names(sym->name, pair->name) == 0) {
305 /*
306 * kallsyms don't have the symbol end, so we
307 * set that by using the next symbol start - 1,
308 * in some cases we get this up to a page
309 * wrong, trace_kmalloc when I was developing
310 * this code was one such example, 2106 bytes
311 * off the real size. More than that and we
312 * _really_ have a problem.
313 */
314 s64 skew = mem_end - UM(pair->end);
315 if (llabs(skew) >= page_size)
316 pr_debug("WARN: %#" PRIx64 ": diff end addr for %s v: %#" PRIx64 " k: %#" PRIx64 "\n",
317 mem_start, sym->name, mem_end,
318 UM(pair->end));
319
320 /*
321 * Do not count this as a failure, because we
322 * could really find a case where it's not
323 * possible to get proper function end from
324 * kallsyms.
325 */
326 continue;
327 } else {
328 pair = machine__find_kernel_symbol_by_name(&args.kallsyms,
329 sym->name, NULL);
330 if (pair) {
331 if (UM(pair->start) == mem_start)
332 goto next_pair;
333
334 pr_debug("WARN: %#" PRIx64 ": diff name v: %s k: %s\n",
335 mem_start, sym->name, pair->name);
336 } else {
337 pr_debug("WARN: %#" PRIx64 ": diff name v: %s k: %s\n",
338 mem_start, sym->name, first_pair->name);
339 }
340
341 continue;
342 }
343 } else if (mem_start == map__end(args.kallsyms.vmlinux_map)) {
344 /*
345 * Ignore aliases to _etext, i.e. to the end of the kernel text area,
346 * such as __indirect_thunk_end.
347 */
348 continue;
349 } else if (is_ignored_symbol(sym->name, sym->type)) {
350 /*
351 * Ignore hidden symbols, see scripts/kallsyms.c for the details
352 */
353 continue;
354 } else {
355 pr_debug("ERR : %#" PRIx64 ": %s not on kallsyms\n",
356 mem_start, sym->name);
357 }
358
359 err = -1;
360 }
361
362 if (verbose <= 0)
363 goto out;
364
365 args.header_printed = false;
366 maps__for_each_map(maps, test__vmlinux_matches_kallsyms_cb1, &args);
367
368 args.header_printed = false;
369 maps__for_each_map(maps, test__vmlinux_matches_kallsyms_cb2, &args);
370
371 args.header_printed = false;
372 maps = machine__kernel_maps(&args.kallsyms);
373 maps__for_each_map(maps, test__vmlinux_matches_kallsyms_cb3, &args);
374
375 out:
376 machine__exit(&args.kallsyms);
377 machine__exit(&vmlinux);
378 return err;
379 }
380
381 DEFINE_SUITE("vmlinux symtab matches kallsyms", vmlinux_matches_kallsyms);
382