1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Test the function and performance of kallsyms
4 *
5 * Copyright (C) Huawei Technologies Co., Ltd., 2022
6 *
7 * Authors: Zhen Lei <thunder.leizhen@huawei.com> Huawei
8 */
9
10 #define pr_fmt(fmt) "kallsyms_selftest: " fmt
11
12 #include <linux/init.h>
13 #include <linux/module.h>
14 #include <linux/kallsyms.h>
15 #include <linux/random.h>
16 #include <linux/sched/clock.h>
17 #include <linux/kthread.h>
18 #include <linux/vmalloc.h>
19
20 #include "kallsyms_internal.h"
21 #include "kallsyms_selftest.h"
22
23
24 #define MAX_NUM_OF_RECORDS 64
25
26 struct test_stat {
27 int min;
28 int max;
29 int save_cnt;
30 int real_cnt;
31 int perf;
32 u64 sum;
33 char *name;
34 unsigned long addr;
35 unsigned long addrs[MAX_NUM_OF_RECORDS];
36 };
37
38 struct test_item {
39 char *name;
40 unsigned long addr;
41 };
42
43 #define ITEM_FUNC(s) \
44 { \
45 .name = #s, \
46 .addr = (unsigned long)s, \
47 }
48
49 #define ITEM_DATA(s) \
50 { \
51 .name = #s, \
52 .addr = (unsigned long)&s, \
53 }
54
55
56 static int kallsyms_test_var_bss_static;
57 static int kallsyms_test_var_data_static = 1;
58 int kallsyms_test_var_bss;
59 int kallsyms_test_var_data = 1;
60
kallsyms_test_func_static(void)61 static int kallsyms_test_func_static(void)
62 {
63 kallsyms_test_var_bss_static++;
64 kallsyms_test_var_data_static++;
65
66 return 0;
67 }
68
kallsyms_test_func(void)69 int kallsyms_test_func(void)
70 {
71 return kallsyms_test_func_static();
72 }
73
kallsyms_test_func_weak(void)74 __weak int kallsyms_test_func_weak(void)
75 {
76 kallsyms_test_var_bss++;
77 kallsyms_test_var_data++;
78 return 0;
79 }
80
81 static struct test_item test_items[] = {
82 ITEM_FUNC(kallsyms_test_func_static),
83 ITEM_FUNC(kallsyms_test_func),
84 ITEM_FUNC(kallsyms_test_func_weak),
85 ITEM_FUNC(vmalloc),
86 ITEM_FUNC(vfree),
87 #ifdef CONFIG_KALLSYMS_ALL
88 ITEM_DATA(kallsyms_test_var_bss_static),
89 ITEM_DATA(kallsyms_test_var_data_static),
90 ITEM_DATA(kallsyms_test_var_bss),
91 ITEM_DATA(kallsyms_test_var_data),
92 ITEM_DATA(vmap_area_list),
93 #endif
94 };
95
96 static char stub_name[KSYM_NAME_LEN];
97
stat_symbol_len(void * data,const char * name,struct module * mod,unsigned long addr)98 static int stat_symbol_len(void *data, const char *name, struct module *mod, unsigned long addr)
99 {
100 *(u32 *)data += strlen(name);
101
102 return 0;
103 }
104
test_kallsyms_compression_ratio(void)105 static void test_kallsyms_compression_ratio(void)
106 {
107 u32 pos, off, len, num;
108 u32 ratio, total_size, total_len = 0;
109
110 kallsyms_on_each_symbol(stat_symbol_len, &total_len);
111
112 /*
113 * A symbol name cannot start with a number. This stub name helps us
114 * traverse the entire symbol table without finding a match. It's used
115 * for subsequent performance tests, and its length is the average
116 * length of all symbol names.
117 */
118 memset(stub_name, '4', sizeof(stub_name));
119 pos = total_len / kallsyms_num_syms;
120 stub_name[pos] = 0;
121
122 pos = 0;
123 num = 0;
124 off = 0;
125 while (pos < kallsyms_num_syms) {
126 len = kallsyms_names[off];
127 num++;
128 off++;
129 pos++;
130 if ((len & 0x80) != 0) {
131 len = (len & 0x7f) | (kallsyms_names[off] << 7);
132 num++;
133 off++;
134 }
135 off += len;
136 }
137
138 /*
139 * 1. The length fields is not counted
140 * 2. The memory occupied by array kallsyms_token_table[] and
141 * kallsyms_token_index[] needs to be counted.
142 */
143 total_size = off - num;
144 pos = kallsyms_token_index[0xff];
145 total_size += pos + strlen(&kallsyms_token_table[pos]) + 1;
146 total_size += 0x100 * sizeof(u16);
147
148 pr_info(" ---------------------------------------------------------\n");
149 pr_info("| nr_symbols | compressed size | original size | ratio(%%) |\n");
150 pr_info("|---------------------------------------------------------|\n");
151 ratio = (u32)div_u64(10000ULL * total_size, total_len);
152 pr_info("| %10d | %10d | %10d | %2d.%-2d |\n",
153 kallsyms_num_syms, total_size, total_len, ratio / 100, ratio % 100);
154 pr_info(" ---------------------------------------------------------\n");
155 }
156
lookup_name(void * data,const char * name,struct module * mod,unsigned long addr)157 static int lookup_name(void *data, const char *name, struct module *mod, unsigned long addr)
158 {
159 u64 t0, t1, t;
160 struct test_stat *stat = (struct test_stat *)data;
161
162 t0 = ktime_get_ns();
163 (void)kallsyms_lookup_name(name);
164 t1 = ktime_get_ns();
165
166 t = t1 - t0;
167 if (t < stat->min)
168 stat->min = t;
169
170 if (t > stat->max)
171 stat->max = t;
172
173 stat->real_cnt++;
174 stat->sum += t;
175
176 return 0;
177 }
178
test_perf_kallsyms_lookup_name(void)179 static void test_perf_kallsyms_lookup_name(void)
180 {
181 struct test_stat stat;
182
183 memset(&stat, 0, sizeof(stat));
184 stat.min = INT_MAX;
185 kallsyms_on_each_symbol(lookup_name, &stat);
186 pr_info("kallsyms_lookup_name() looked up %d symbols\n", stat.real_cnt);
187 pr_info("The time spent on each symbol is (ns): min=%d, max=%d, avg=%lld\n",
188 stat.min, stat.max, div_u64(stat.sum, stat.real_cnt));
189 }
190
match_cleanup_name(const char * s,const char * name)191 static bool match_cleanup_name(const char *s, const char *name)
192 {
193 char *p;
194 int len;
195
196 if (!IS_ENABLED(CONFIG_LTO_CLANG))
197 return false;
198
199 p = strchr(s, '.');
200 if (!p)
201 return false;
202
203 len = strlen(name);
204 if (p - s != len)
205 return false;
206
207 return !strncmp(s, name, len);
208 }
209
find_symbol(void * data,const char * name,struct module * mod,unsigned long addr)210 static int find_symbol(void *data, const char *name, struct module *mod, unsigned long addr)
211 {
212 struct test_stat *stat = (struct test_stat *)data;
213
214 if (strcmp(name, stat->name) == 0 ||
215 (!stat->perf && match_cleanup_name(name, stat->name))) {
216 stat->real_cnt++;
217 stat->addr = addr;
218
219 if (stat->save_cnt < MAX_NUM_OF_RECORDS) {
220 stat->addrs[stat->save_cnt] = addr;
221 stat->save_cnt++;
222 }
223
224 if (stat->real_cnt == stat->max)
225 return 1;
226 }
227
228 return 0;
229 }
230
test_perf_kallsyms_on_each_symbol(void)231 static void test_perf_kallsyms_on_each_symbol(void)
232 {
233 u64 t0, t1;
234 struct test_stat stat;
235
236 memset(&stat, 0, sizeof(stat));
237 stat.max = INT_MAX;
238 stat.name = stub_name;
239 stat.perf = 1;
240 t0 = ktime_get_ns();
241 kallsyms_on_each_symbol(find_symbol, &stat);
242 t1 = ktime_get_ns();
243 pr_info("kallsyms_on_each_symbol() traverse all: %lld ns\n", t1 - t0);
244 }
245
match_symbol(void * data,unsigned long addr)246 static int match_symbol(void *data, unsigned long addr)
247 {
248 struct test_stat *stat = (struct test_stat *)data;
249
250 stat->real_cnt++;
251 stat->addr = addr;
252
253 if (stat->save_cnt < MAX_NUM_OF_RECORDS) {
254 stat->addrs[stat->save_cnt] = addr;
255 stat->save_cnt++;
256 }
257
258 if (stat->real_cnt == stat->max)
259 return 1;
260
261 return 0;
262 }
263
test_perf_kallsyms_on_each_match_symbol(void)264 static void test_perf_kallsyms_on_each_match_symbol(void)
265 {
266 u64 t0, t1;
267 struct test_stat stat;
268
269 memset(&stat, 0, sizeof(stat));
270 stat.max = INT_MAX;
271 stat.name = stub_name;
272 t0 = ktime_get_ns();
273 kallsyms_on_each_match_symbol(match_symbol, stat.name, &stat);
274 t1 = ktime_get_ns();
275 pr_info("kallsyms_on_each_match_symbol() traverse all: %lld ns\n", t1 - t0);
276 }
277
test_kallsyms_basic_function(void)278 static int test_kallsyms_basic_function(void)
279 {
280 int i, j, ret;
281 int next = 0, nr_failed = 0;
282 char *prefix;
283 unsigned short rand;
284 unsigned long addr, lookup_addr;
285 char namebuf[KSYM_NAME_LEN];
286 struct test_stat *stat, *stat2;
287
288 stat = kmalloc(sizeof(*stat) * 2, GFP_KERNEL);
289 if (!stat)
290 return -ENOMEM;
291 stat2 = stat + 1;
292
293 prefix = "kallsyms_lookup_name() for";
294 for (i = 0; i < ARRAY_SIZE(test_items); i++) {
295 addr = kallsyms_lookup_name(test_items[i].name);
296 if (addr != test_items[i].addr) {
297 nr_failed++;
298 pr_info("%s %s failed: addr=%lx, expect %lx\n",
299 prefix, test_items[i].name, addr, test_items[i].addr);
300 }
301 }
302
303 prefix = "kallsyms_on_each_symbol() for";
304 for (i = 0; i < ARRAY_SIZE(test_items); i++) {
305 memset(stat, 0, sizeof(*stat));
306 stat->max = INT_MAX;
307 stat->name = test_items[i].name;
308 kallsyms_on_each_symbol(find_symbol, stat);
309 if (stat->addr != test_items[i].addr || stat->real_cnt != 1) {
310 nr_failed++;
311 pr_info("%s %s failed: count=%d, addr=%lx, expect %lx\n",
312 prefix, test_items[i].name,
313 stat->real_cnt, stat->addr, test_items[i].addr);
314 }
315 }
316
317 prefix = "kallsyms_on_each_match_symbol() for";
318 for (i = 0; i < ARRAY_SIZE(test_items); i++) {
319 memset(stat, 0, sizeof(*stat));
320 stat->max = INT_MAX;
321 stat->name = test_items[i].name;
322 kallsyms_on_each_match_symbol(match_symbol, test_items[i].name, stat);
323 if (stat->addr != test_items[i].addr || stat->real_cnt != 1) {
324 nr_failed++;
325 pr_info("%s %s failed: count=%d, addr=%lx, expect %lx\n",
326 prefix, test_items[i].name,
327 stat->real_cnt, stat->addr, test_items[i].addr);
328 }
329 }
330
331 if (nr_failed) {
332 kfree(stat);
333 return -ESRCH;
334 }
335
336 for (i = 0; i < kallsyms_num_syms; i++) {
337 addr = kallsyms_sym_address(i);
338 if (!is_ksym_addr(addr))
339 continue;
340
341 ret = lookup_symbol_name(addr, namebuf);
342 if (unlikely(ret)) {
343 namebuf[0] = 0;
344 goto failed;
345 }
346
347 /*
348 * The first '.' may be the initial letter, in which case the
349 * entire symbol name will be truncated to an empty string in
350 * cleanup_symbol_name(). Do not test these symbols.
351 *
352 * For example:
353 * cat /proc/kallsyms | awk '{print $3}' | grep -E "^\." | head
354 * .E_read_words
355 * .E_leading_bytes
356 * .E_trailing_bytes
357 * .E_write_words
358 * .E_copy
359 * .str.292.llvm.12122243386960820698
360 * .str.24.llvm.12122243386960820698
361 * .str.29.llvm.12122243386960820698
362 * .str.75.llvm.12122243386960820698
363 * .str.99.llvm.12122243386960820698
364 */
365 if (IS_ENABLED(CONFIG_LTO_CLANG) && !namebuf[0])
366 continue;
367
368 lookup_addr = kallsyms_lookup_name(namebuf);
369
370 memset(stat, 0, sizeof(*stat));
371 stat->max = INT_MAX;
372 kallsyms_on_each_match_symbol(match_symbol, namebuf, stat);
373
374 /*
375 * kallsyms_on_each_symbol() is too slow, randomly select some
376 * symbols for test.
377 */
378 if (i >= next) {
379 memset(stat2, 0, sizeof(*stat2));
380 stat2->max = INT_MAX;
381 stat2->name = namebuf;
382 kallsyms_on_each_symbol(find_symbol, stat2);
383
384 /*
385 * kallsyms_on_each_symbol() and kallsyms_on_each_match_symbol()
386 * need to get the same traversal result.
387 */
388 if (stat->addr != stat2->addr ||
389 stat->real_cnt != stat2->real_cnt ||
390 memcmp(stat->addrs, stat2->addrs,
391 stat->save_cnt * sizeof(stat->addrs[0])))
392 goto failed;
393
394 /*
395 * The average of random increments is 128, that is, one of
396 * them is tested every 128 symbols.
397 */
398 get_random_bytes(&rand, sizeof(rand));
399 next = i + (rand & 0xff) + 1;
400 }
401
402 /* Need to be found at least once */
403 if (!stat->real_cnt)
404 goto failed;
405
406 /*
407 * kallsyms_lookup_name() returns the address of the first
408 * symbol found and cannot be NULL.
409 */
410 if (!lookup_addr || lookup_addr != stat->addrs[0])
411 goto failed;
412
413 /*
414 * If the addresses of all matching symbols are recorded, the
415 * target address needs to be exist.
416 */
417 if (stat->real_cnt <= MAX_NUM_OF_RECORDS) {
418 for (j = 0; j < stat->save_cnt; j++) {
419 if (stat->addrs[j] == addr)
420 break;
421 }
422
423 if (j == stat->save_cnt)
424 goto failed;
425 }
426 }
427
428 kfree(stat);
429
430 return 0;
431
432 failed:
433 pr_info("Test for %dth symbol failed: (%s) addr=%lx", i, namebuf, addr);
434 kfree(stat);
435 return -ESRCH;
436 }
437
test_entry(void * p)438 static int test_entry(void *p)
439 {
440 int ret;
441
442 do {
443 schedule_timeout(5 * HZ);
444 } while (system_state != SYSTEM_RUNNING);
445
446 pr_info("start\n");
447 ret = test_kallsyms_basic_function();
448 if (ret) {
449 pr_info("abort\n");
450 return 0;
451 }
452
453 test_kallsyms_compression_ratio();
454 test_perf_kallsyms_lookup_name();
455 test_perf_kallsyms_on_each_symbol();
456 test_perf_kallsyms_on_each_match_symbol();
457 pr_info("finish\n");
458
459 return 0;
460 }
461
kallsyms_test_init(void)462 static int __init kallsyms_test_init(void)
463 {
464 struct task_struct *t;
465
466 t = kthread_create(test_entry, NULL, "kallsyms_test");
467 if (IS_ERR(t)) {
468 pr_info("Create kallsyms selftest task failed\n");
469 return PTR_ERR(t);
470 }
471 kthread_bind(t, 0);
472 wake_up_process(t);
473
474 return 0;
475 }
476 late_initcall(kallsyms_test_init);
477