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_relative_base",
31 "kallsyms_num_syms",
32 "kallsyms_names",
33 "kallsyms_markers",
34 "kallsyms_token_table",
35 "kallsyms_token_index",
36 /* Exclude linker generated symbols which vary between passes */
37 "_SDA_BASE_", /* ppc */
38 "_SDA2_BASE_", /* ppc */
39 NULL
40 };
41
42 /* Symbol names that begin with the following are ignored.*/
43 static const char * const ignored_prefixes[] = {
44 "$", /* local symbols for ARM, MIPS, etc. */
45 ".L", /* local labels, .LBB,.Ltmpxxx,.L__unnamed_xx,.LASANPC, etc. */
46 "__crc_", /* modversions */
47 "__efistub_", /* arm64 EFI stub namespace */
48 "__kvm_nvhe_$", /* arm64 local symbols in non-VHE KVM namespace */
49 "__kvm_nvhe_.L", /* arm64 local symbols in 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 struct test__vmlinux_matches_kallsyms_cb_args {
115 struct machine kallsyms;
116 struct map *vmlinux_map;
117 bool header_printed;
118 };
119
test__vmlinux_matches_kallsyms_cb1(struct map * map,void * data)120 static int test__vmlinux_matches_kallsyms_cb1(struct map *map, void *data)
121 {
122 struct test__vmlinux_matches_kallsyms_cb_args *args = data;
123 struct dso *dso = map__dso(map);
124 /*
125 * If it is the kernel, kallsyms is always "[kernel.kallsyms]", while
126 * the kernel will have the path for the vmlinux file being used, so use
127 * the short name, less descriptive but the same ("[kernel]" in both
128 * cases.
129 */
130 struct map *pair = maps__find_by_name(args->kallsyms.kmaps,
131 (dso__kernel(dso) ? dso__short_name(dso) : dso__name(dso)));
132
133 if (pair) {
134 map__set_priv(pair);
135 map__put(pair);
136 } else {
137 if (!args->header_printed) {
138 pr_info("WARN: Maps only in vmlinux:\n");
139 args->header_printed = true;
140 }
141 map__fprintf(map, stderr);
142 }
143 return 0;
144 }
145
test__vmlinux_matches_kallsyms_cb2(struct map * map,void * data)146 static int test__vmlinux_matches_kallsyms_cb2(struct map *map, void *data)
147 {
148 struct test__vmlinux_matches_kallsyms_cb_args *args = data;
149 struct map *pair;
150 u64 mem_start = map__unmap_ip(args->vmlinux_map, map__start(map));
151 u64 mem_end = map__unmap_ip(args->vmlinux_map, map__end(map));
152
153 pair = maps__find(args->kallsyms.kmaps, mem_start);
154
155 if (pair != NULL && !map__priv(pair) && map__start(pair) == mem_start) {
156 struct dso *dso = map__dso(map);
157
158 if (!args->header_printed) {
159 pr_info("WARN: Maps in vmlinux with a different name in kallsyms:\n");
160 args->header_printed = true;
161 }
162
163 pr_info("WARN: %" PRIx64 "-%" PRIx64 " %" PRIx64 " %s in kallsyms as",
164 map__start(map), map__end(map), map__pgoff(map), dso__name(dso));
165 if (mem_end != map__end(pair))
166 pr_info(":\nWARN: *%" PRIx64 "-%" PRIx64 " %" PRIx64,
167 map__start(pair), map__end(pair), map__pgoff(pair));
168 pr_info(" %s\n", dso__name(dso));
169 map__set_priv(pair);
170 }
171 map__put(pair);
172 return 0;
173 }
174
test__vmlinux_matches_kallsyms_cb3(struct map * map,void * data)175 static int test__vmlinux_matches_kallsyms_cb3(struct map *map, void *data)
176 {
177 struct test__vmlinux_matches_kallsyms_cb_args *args = data;
178
179 if (!map__priv(map)) {
180 if (!args->header_printed) {
181 pr_info("WARN: Maps only in kallsyms:\n");
182 args->header_printed = true;
183 }
184 map__fprintf(map, stderr);
185 }
186 return 0;
187 }
188
test__vmlinux_matches_kallsyms(struct test_suite * test __maybe_unused,int subtest __maybe_unused)189 static int test__vmlinux_matches_kallsyms(struct test_suite *test __maybe_unused,
190 int subtest __maybe_unused)
191 {
192 int err = TEST_FAIL;
193 struct rb_node *nd;
194 struct symbol *sym;
195 struct map *kallsyms_map;
196 struct machine vmlinux;
197 struct maps *maps;
198 u64 mem_start, mem_end;
199 struct test__vmlinux_matches_kallsyms_cb_args args;
200
201 /*
202 * Step 1:
203 *
204 * Init the machines that will hold kernel, modules obtained from
205 * both vmlinux + .ko files and from /proc/kallsyms split by modules.
206 */
207 machine__init(&args.kallsyms, "", HOST_KERNEL_ID);
208 machine__init(&vmlinux, "", HOST_KERNEL_ID);
209
210 maps = machine__kernel_maps(&vmlinux);
211
212 /*
213 * Step 2:
214 *
215 * Create the kernel maps for kallsyms and the DSO where we will then
216 * load /proc/kallsyms. Also create the modules maps from /proc/modules
217 * and find the .ko files that match them in /lib/modules/`uname -r`/.
218 */
219 if (machine__create_kernel_maps(&args.kallsyms) < 0) {
220 pr_debug("machine__create_kernel_maps failed");
221 err = TEST_SKIP;
222 goto out;
223 }
224
225 /*
226 * Step 3:
227 *
228 * Load and split /proc/kallsyms into multiple maps, one per module.
229 * Do not use kcore, as this test was designed before kcore support
230 * and has parts that only make sense if using the non-kcore code.
231 * XXX: extend it to stress the kcorre code as well, hint: the list
232 * of modules extracted from /proc/kcore, in its current form, can't
233 * be compacted against the list of modules found in the "vmlinux"
234 * code and with the one got from /proc/modules from the "kallsyms" code.
235 */
236 if (machine__load_kallsyms(&args.kallsyms, "/proc/kallsyms") <= 0) {
237 pr_debug("machine__load_kallsyms failed");
238 err = TEST_SKIP;
239 goto out;
240 }
241
242 /*
243 * Step 4:
244 *
245 * kallsyms will be internally on demand sorted by name so that we can
246 * find the reference relocation * symbol, i.e. the symbol we will use
247 * to see if the running kernel was relocated by checking if it has the
248 * same value in the vmlinux file we load.
249 */
250 kallsyms_map = machine__kernel_map(&args.kallsyms);
251
252 /*
253 * Step 5:
254 *
255 * Now repeat step 2, this time for the vmlinux file we'll auto-locate.
256 */
257 if (machine__create_kernel_maps(&vmlinux) < 0) {
258 pr_info("machine__create_kernel_maps failed");
259 goto out;
260 }
261
262 args.vmlinux_map = machine__kernel_map(&vmlinux);
263
264 /*
265 * Step 6:
266 *
267 * Locate a vmlinux file in the vmlinux path that has a buildid that
268 * matches the one of the running kernel.
269 *
270 * While doing that look if we find the ref reloc symbol, if we find it
271 * we'll have its ref_reloc_symbol.unrelocated_addr and then
272 * maps__reloc_vmlinux will notice and set proper ->[un]map_ip routines
273 * to fixup the symbols.
274 */
275 if (machine__load_vmlinux_path(&vmlinux) <= 0) {
276 pr_info("Couldn't find a vmlinux that matches the kernel running on this machine, skipping test\n");
277 err = TEST_SKIP;
278 goto out;
279 }
280
281 err = 0;
282 /*
283 * Step 7:
284 *
285 * Now look at the symbols in the vmlinux DSO and check if we find all of them
286 * in the kallsyms dso. For the ones that are in both, check its names and
287 * end addresses too.
288 */
289 map__for_each_symbol(args.vmlinux_map, sym, nd) {
290 struct symbol *pair, *first_pair;
291
292 sym = rb_entry(nd, struct symbol, rb_node);
293
294 if (sym->start == sym->end)
295 continue;
296
297 mem_start = map__unmap_ip(args.vmlinux_map, sym->start);
298 mem_end = map__unmap_ip(args.vmlinux_map, sym->end);
299
300 first_pair = machine__find_kernel_symbol(&args.kallsyms, mem_start, NULL);
301 pair = first_pair;
302
303 if (pair && UM(pair->start) == mem_start) {
304 next_pair:
305 if (arch__compare_symbol_names(sym->name, pair->name) == 0) {
306 /*
307 * kallsyms don't have the symbol end, so we
308 * set that by using the next symbol start - 1,
309 * in some cases we get this up to a page
310 * wrong, trace_kmalloc when I was developing
311 * this code was one such example, 2106 bytes
312 * off the real size. More than that and we
313 * _really_ have a problem.
314 */
315 s64 skew = mem_end - UM(pair->end);
316 if (llabs(skew) >= page_size)
317 pr_debug("WARN: %#" PRIx64 ": diff end addr for %s v: %#" PRIx64 " k: %#" PRIx64 "\n",
318 mem_start, sym->name, mem_end,
319 UM(pair->end));
320
321 /*
322 * Do not count this as a failure, because we
323 * could really find a case where it's not
324 * possible to get proper function end from
325 * kallsyms.
326 */
327 continue;
328 } else {
329 pair = machine__find_kernel_symbol_by_name(&args.kallsyms,
330 sym->name, NULL);
331 if (pair) {
332 if (UM(pair->start) == mem_start)
333 goto next_pair;
334
335 pr_debug("WARN: %#" PRIx64 ": diff name v: %s k: %s\n",
336 mem_start, sym->name, pair->name);
337 } else {
338 pr_debug("WARN: %#" PRIx64 ": diff name v: %s k: %s\n",
339 mem_start, sym->name, first_pair->name);
340 }
341
342 continue;
343 }
344 } else if (mem_start == map__end(args.kallsyms.vmlinux_map)) {
345 /*
346 * Ignore aliases to _etext, i.e. to the end of the kernel text area,
347 * such as __indirect_thunk_end.
348 */
349 continue;
350 } else if (is_ignored_symbol(sym->name, sym->type)) {
351 /*
352 * Ignore hidden symbols, see scripts/kallsyms.c for the details
353 */
354 continue;
355 } else {
356 pr_debug("ERR : %#" PRIx64 ": %s not on kallsyms\n",
357 mem_start, sym->name);
358 }
359
360 err = -1;
361 }
362
363 if (verbose <= 0)
364 goto out;
365
366 args.header_printed = false;
367 maps__for_each_map(maps, test__vmlinux_matches_kallsyms_cb1, &args);
368
369 args.header_printed = false;
370 maps__for_each_map(maps, test__vmlinux_matches_kallsyms_cb2, &args);
371
372 args.header_printed = false;
373 maps = machine__kernel_maps(&args.kallsyms);
374 maps__for_each_map(maps, test__vmlinux_matches_kallsyms_cb3, &args);
375
376 out:
377 machine__exit(&args.kallsyms);
378 machine__exit(&vmlinux);
379 return err;
380 }
381
382 DEFINE_SUITE("vmlinux symtab matches kallsyms", vmlinux_matches_kallsyms);
383