summaryrefslogtreecommitdiff
path: root/scripts/mod/modpost.c
blob: b3dee80497cb2b1fdfa488d42c14294def73749a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
/* Postprocess module symbol versions
 *
 * Copyright 2003       Kai Germaschewski
 * Copyright 2002-2004  Rusty Russell, IBM Corporation
 * Copyright 2006-2008  Sam Ravnborg
 * Based in part on module-init-tools/depmod.c,file2alias
 *
 * This software may be used and distributed according to the terms
 * of the GNU General Public License, incorporated herein by reference.
 *
 * Usage: modpost vmlinux module1.o module2.o ...
 */

#define _GNU_SOURCE
#include <elf.h>
#include <fnmatch.h>
#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <limits.h>
#include <stdbool.h>
#include <errno.h>
#include "modpost.h"
#include "../../include/linux/license.h"
#include "../../include/linux/module_symbol.h"

static bool module_enabled;
/* Are we using CONFIG_MODVERSIONS? */
static bool modversions;
/* Is CONFIG_MODULE_SRCVERSION_ALL set? */
static bool all_versions;
/* If we are modposting external module set to 1 */
static bool external_module;
/* Only warn about unresolved symbols */
static bool warn_unresolved;

static int sec_mismatch_count;
static bool sec_mismatch_warn_only = true;
/* Trim EXPORT_SYMBOLs that are unused by in-tree modules */
static bool trim_unused_exports;

/* ignore missing files */
static bool ignore_missing_files;
/* If set to 1, only warn (instead of error) about missing ns imports */
static bool allow_missing_ns_imports;

static bool error_occurred;

static bool extra_warn;

/*
 * Cut off the warnings when there are too many. This typically occurs when
 * vmlinux is missing. ('make modules' without building vmlinux.)
 */
#define MAX_UNRESOLVED_REPORTS	10
static unsigned int nr_unresolved;

/* In kernel, this size is defined in linux/module.h;
 * here we use Elf_Addr instead of long for covering cross-compile
 */

#define MODULE_NAME_LEN (64 - sizeof(Elf_Addr))

void __attribute__((format(printf, 2, 3)))
modpost_log(enum loglevel loglevel, const char *fmt, ...)
{
	va_list arglist;

	switch (loglevel) {
	case LOG_WARN:
		fprintf(stderr, "WARNING: ");
		break;
	case LOG_ERROR:
		fprintf(stderr, "ERROR: ");
		break;
	case LOG_FATAL:
		fprintf(stderr, "FATAL: ");
		break;
	default: /* invalid loglevel, ignore */
		break;
	}

	fprintf(stderr, "modpost: ");

	va_start(arglist, fmt);
	vfprintf(stderr, fmt, arglist);
	va_end(arglist);

	if (loglevel == LOG_FATAL)
		exit(1);
	if (loglevel == LOG_ERROR)
		error_occurred = true;
}

static inline bool strends(const char *str, const char *postfix)
{
	if (strlen(str) < strlen(postfix))
		return false;

	return strcmp(str + strlen(str) - strlen(postfix), postfix) == 0;
}

void *do_nofail(void *ptr, const char *expr)
{
	if (!ptr)
		fatal("Memory allocation failure: %s.\n", expr);

	return ptr;
}

char *read_text_file(const char *filename)
{
	struct stat st;
	size_t nbytes;
	int fd;
	char *buf;

	fd = open(filename, O_RDONLY);
	if (fd < 0) {
		perror(filename);
		exit(1);
	}

	if (fstat(fd, &st) < 0) {
		perror(filename);
		exit(1);
	}

	buf = NOFAIL(malloc(st.st_size + 1));

	nbytes = st.st_size;

	while (nbytes) {
		ssize_t bytes_read;

		bytes_read = read(fd, buf, nbytes);
		if (bytes_read < 0) {
			perror(filename);
			exit(1);
		}

		nbytes -= bytes_read;
	}
	buf[st.st_size] = '\0';

	close(fd);

	return buf;
}

char *get_line(char **stringp)
{
	char *orig = *stringp, *next;

	/* do not return the unwanted extra line at EOF */
	if (!orig || *orig == '\0')
		return NULL;

	/* don't use strsep here, it is not available everywhere */
	next = strchr(orig, '\n');
	if (next)
		*next++ = '\0';

	*stringp = next;

	return orig;
}

/* A list of all modules we processed */
LIST_HEAD(modules);

static struct module *find_module(const char *modname)
{
	struct module *mod;

	list_for_each_entry(mod, &modules, list) {
		if (strcmp(mod->name, modname) == 0)
			return mod;
	}
	return NULL;
}

static struct module *new_module(const char *name, size_t namelen)
{
	struct module *mod;

	mod = NOFAIL(malloc(sizeof(*mod) + namelen + 1));
	memset(mod, 0, sizeof(*mod));

	INIT_LIST_HEAD(&mod->exported_symbols);
	INIT_LIST_HEAD(&mod->unresolved_symbols);
	INIT_LIST_HEAD(&mod->missing_namespaces);
	INIT_LIST_HEAD(&mod->imported_namespaces);

	memcpy(mod->name, name, namelen);
	mod->name[namelen] = '\0';
	mod->is_vmlinux = (strcmp(mod->name, "vmlinux") == 0);

	/*
	 * Set mod->is_gpl_compatible to true by default. If MODULE_LICENSE()
	 * is missing, do not check the use for EXPORT_SYMBOL_GPL() becasue
	 * modpost will exit wiht error anyway.
	 */
	mod->is_gpl_compatible = true;

	list_add_tail(&mod->list, &modules);

	return mod;
}

/* A hash of all exported symbols,
 * struct symbol is also used for lists of unresolved symbols */

#define SYMBOL_HASH_SIZE 1024

struct symbol {
	struct symbol *next;
	struct list_head list;	/* link to module::exported_symbols or module::unresolved_symbols */
	struct module *module;
	char *namespace;
	unsigned int crc;
	bool crc_valid;
	bool weak;
	bool is_func;
	bool is_gpl_only;	/* exported by EXPORT_SYMBOL_GPL */
	bool used;		/* there exists a user of this symbol */
	char name[];
};

static struct symbol *symbolhash[SYMBOL_HASH_SIZE];

/* This is based on the hash algorithm from gdbm, via tdb */
static inline unsigned int tdb_hash(const char *name)
{
	unsigned value;	/* Used to compute the hash value.  */
	unsigned   i;	/* Used to cycle through random values. */

	/* Set the initial value from the key size. */
	for (value = 0x238F13AF * strlen(name), i = 0; name[i]; i++)
		value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));

	return (1103515243 * value + 12345);
}

/**
 * Allocate a new symbols for use in the hash of exported symbols or
 * the list of unresolved symbols per module
 **/
static struct symbol *alloc_symbol(const char *name)
{
	struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));

	memset(s, 0, sizeof(*s));
	strcpy(s->name, name);

	return s;
}

/* For the hash of exported symbols */
static void hash_add_symbol(struct symbol *sym)
{
	unsigned int hash;

	hash = tdb_hash(sym->name) % SYMBOL_HASH_SIZE;
	sym->next = symbolhash[hash];
	symbolhash[hash] = sym;
}

static void sym_add_unresolved(const char *name, struct module *mod, bool weak)
{
	struct symbol *sym;

	sym = alloc_symbol(name);
	sym->weak = weak;

	list_add_tail(&sym->list, &mod->unresolved_symbols);
}

static struct symbol *sym_find_with_module(const char *name, struct module *mod)
{
	struct symbol *s;

	/* For our purposes, .foo matches foo.  PPC64 needs this. */
	if (name[0] == '.')
		name++;

	for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s = s->next) {
		if (strcmp(s->name, name) == 0 && (!mod || s->module == mod))
			return s;
	}
	return NULL;
}

static struct symbol *find_symbol(const char *name)
{
	return sym_find_with_module(name, NULL);
}

struct namespace_list {
	struct list_head list;
	char namespace[];
};

static bool contains_namespace(struct list_head *head, const char *namespace)
{
	struct namespace_list *list;

	/*
	 * The default namespace is null string "", which is always implicitly
	 * contained.
	 */
	if (!namespace[0])
		return true;

	list_for_each_entry(list, head, list) {
		if (!strcmp(list->namespace, namespace))
			return true;
	}

	return false;
}

static void add_namespace(struct list_head *head, const char *namespace)
{
	struct namespace_list *ns_entry;

	if (!contains_namespace(head, namespace)) {
		ns_entry = NOFAIL(malloc(sizeof(*ns_entry) +
					 strlen(namespace) + 1));
		strcpy(ns_entry->namespace, namespace);
		list_add_tail(&ns_entry->list, head);
	}
}

static void *sym_get_data_by_offset(const struct elf_info *info,
				    unsigned int secindex, unsigned long offset)
{
	Elf_Shdr *sechdr = &info->sechdrs[secindex];

	return (void *)info->hdr + sechdr->sh_offset + offset;
}

void *sym_get_data(const struct elf_info *info, const Elf_Sym *sym)
{
	return sym_get_data_by_offset(info, get_secindex(info, sym),
				      sym->st_value);
}

static const char *sech_name(const struct elf_info *info, Elf_Shdr *sechdr)
{
	return sym_get_data_by_offset(info, info->secindex_strings,
				      sechdr->sh_name);
}

static const char *sec_name(const struct elf_info *info, unsigned int secindex)
{
	/*
	 * If sym->st_shndx is a special section index, there is no
	 * corresponding section header.
	 * Return "" if the index is out of range of info->sechdrs[] array.
	 */
	if (secindex >= info->num_sections)
		return "";

	return sech_name(info, &info->sechdrs[secindex]);
}

#define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0)

static struct symbol *sym_add_exported(const char *name, struct module *mod,
				       bool gpl_only, const char *namespace)
{
	struct symbol *s = find_symbol(name);

	if (s && (!external_module || s->module->is_vmlinux || s->module == mod)) {
		error("%s: '%s' exported twice. Previous export was in %s%s\n",
		      mod->name, name, s->module->name,
		      s->module->is_vmlinux ? "" : ".ko");
	}

	s = alloc_symbol(name);
	s->module = mod;
	s->is_gpl_only = gpl_only;
	s->namespace = NOFAIL(strdup(namespace));
	list_add_tail(&s->list, &mod->exported_symbols);
	hash_add_symbol(s);

	return s;
}

static void sym_set_crc(struct symbol *sym, unsigned int crc)
{
	sym->crc = crc;
	sym->crc_valid = true;
}

static void *grab_file(const char *filename, size_t *size)
{
	struct stat st;
	void *map = MAP_FAILED;
	int fd;

	fd = open(filename, O_RDONLY);
	if (fd < 0)
		return NULL;
	if (fstat(fd, &st))
		goto failed;

	*size = st.st_size;
	map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);

failed:
	close(fd);
	if (map == MAP_FAILED)
		return NULL;
	return map;
}

static void release_file(void *file, size_t size)
{
	munmap(file, size);
}

static int parse_elf(struct elf_info *info, const char *filename)
{
	unsigned int i;
	Elf_Ehdr *hdr;
	Elf_Shdr *sechdrs;
	Elf_Sym  *sym;
	const char *secstrings;
	unsigned int symtab_idx = ~0U, symtab_shndx_idx = ~0U;

	hdr = grab_file(filename, &info->size);
	if (!hdr) {
		if (ignore_missing_files) {
			fprintf(stderr, "%s: %s (ignored)\n", filename,
				strerror(errno));
			return 0;
		}
		perror(filename);
		exit(1);
	}
	info->hdr = hdr;
	if (info->size < sizeof(*hdr)) {
		/* file too small, assume this is an empty .o file */
		return 0;
	}
	/* Is this a valid ELF file? */
	if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
	    (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
	    (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
	    (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
		/* Not an ELF file - silently ignore it */
		return 0;
	}
	/* Fix endianness in ELF header */
	hdr->e_type      = TO_NATIVE(hdr->e_type);
	hdr->e_machine   = TO_NATIVE(hdr->e_machine);
	hdr->e_version   = TO_NATIVE(hdr->e_version);
	hdr->e_entry     = TO_NATIVE(hdr->e_entry);
	hdr->e_phoff     = TO_NATIVE(hdr->e_phoff);
	hdr->e_shoff     = TO_NATIVE(hdr->e_shoff);
	hdr->e_flags     = TO_NATIVE(hdr->e_flags);
	hdr->e_ehsize    = TO_NATIVE(hdr->e_ehsize);
	hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize);
	hdr->e_phnum     = TO_NATIVE(hdr->e_phnum);
	hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize);
	hdr->e_shnum     = TO_NATIVE(hdr->e_shnum);
	hdr->e_shstrndx  = TO_NATIVE(hdr->e_shstrndx);
	sechdrs = (void *)hdr + hdr->e_shoff;
	info->sechdrs = sechdrs;

	/* modpost only works for relocatable objects */
	if (hdr->e_type != ET_REL)
		fatal("%s: not relocatable object.", filename);

	/* Check if file offset is correct */
	if (hdr->e_shoff > info->size) {
		fatal("section header offset=%lu in file '%s' is bigger than filesize=%zu\n",
		      (unsigned long)hdr->e_shoff, filename, info->size);
		return 0;
	}

	if (hdr->e_shnum == SHN_UNDEF) {
		/*
		 * There are more than 64k sections,
		 * read count from .sh_size.
		 */
		info->num_sections = TO_NATIVE(sechdrs[0].sh_size);
	}
	else {
		info->num_sections = hdr->e_shnum;
	}
	if (hdr->e_shstrndx == SHN_XINDEX) {
		info->secindex_strings = TO_NATIVE(sechdrs[0].sh_link);
	}
	else {
		info->secindex_strings = hdr->e_shstrndx;
	}

	/* Fix endianness in section headers */
	for (i = 0; i < info->num_sections; i++) {
		sechdrs[i].sh_name      = TO_NATIVE(sechdrs[i].sh_name);
		sechdrs[i].sh_type      = TO_NATIVE(sechdrs[i].sh_type);
		sechdrs[i].sh_flags     = TO_NATIVE(sechdrs[i].sh_flags);
		sechdrs[i].sh_addr      = TO_NATIVE(sechdrs[i].sh_addr);
		sechdrs[i].sh_offset    = TO_NATIVE(sechdrs[i].sh_offset);
		sechdrs[i].sh_size      = TO_NATIVE(sechdrs[i].sh_size);
		sechdrs[i].sh_link      = TO_NATIVE(sechdrs[i].sh_link);
		sechdrs[i].sh_info      = TO_NATIVE(sechdrs[i].sh_info);
		sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign);
		sechdrs[i].sh_entsize   = TO_NATIVE(sechdrs[i].sh_entsize);
	}
	/* Find symbol table. */
	secstrings = (void *)hdr + sechdrs[info->secindex_strings].sh_offset;
	for (i = 1; i < info->num_sections; i++) {
		const char *secname;
		int nobits = sechdrs[i].sh_type == SHT_NOBITS;

		if (!nobits && sechdrs[i].sh_offset > info->size) {
			fatal("%s is truncated. sechdrs[i].sh_offset=%lu > sizeof(*hrd)=%zu\n",
			      filename, (unsigned long)sechdrs[i].sh_offset,
			      sizeof(*hdr));
			return 0;
		}
		secname = secstrings + sechdrs[i].sh_name;
		if (strcmp(secname, ".modinfo") == 0) {
			if (nobits)
				fatal("%s has NOBITS .modinfo\n", filename);
			info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
			info->modinfo_len = sechdrs[i].sh_size;
		} else if (!strcmp(secname, ".export_symbol")) {
			info->export_symbol_secndx = i;
		}

		if (sechdrs[i].sh_type == SHT_SYMTAB) {
			unsigned int sh_link_idx;
			symtab_idx = i;
			info->symtab_start = (void *)hdr +
			    sechdrs[i].sh_offset;
			info->symtab_stop  = (void *)hdr +
			    sechdrs[i].sh_offset + sechdrs[i].sh_size;
			sh_link_idx = sechdrs[i].sh_link;
			info->strtab       = (void *)hdr +
			    sechdrs[sh_link_idx].sh_offset;
		}

		/* 32bit section no. table? ("more than 64k sections") */
		if (sechdrs[i].sh_type == SHT_SYMTAB_SHNDX) {
			symtab_shndx_idx = i;
			info->symtab_shndx_start = (void *)hdr +
			    sechdrs[i].sh_offset;
			info->symtab_shndx_stop  = (void *)hdr +
			    sechdrs[i].sh_offset + sechdrs[i].sh_size;
		}
	}
	if (!info->symtab_start)
		fatal("%s has no symtab?\n", filename);

	/* Fix endianness in symbols */
	for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
		sym->st_shndx = TO_NATIVE(sym->st_shndx);
		sym->st_name  = TO_NATIVE(sym->st_name);
		sym->st_value = TO_NATIVE(sym->st_value);
		sym->st_size  = TO_NATIVE(sym->st_size);
	}

	if (symtab_shndx_idx != ~0U) {
		Elf32_Word *p;
		if (symtab_idx != sechdrs[symtab_shndx_idx].sh_link)
			fatal("%s: SYMTAB_SHNDX has bad sh_link: %u!=%u\n",
			      filename, sechdrs[symtab_shndx_idx].sh_link,
			      symtab_idx);
		/* Fix endianness */
		for (p = info->symtab_shndx_start; p < info->symtab_shndx_stop;
		     p++)
			*p = TO_NATIVE(*p);
	}

	return 1;
}

static void parse_elf_finish(struct elf_info *info)
{
	release_file(info->hdr, info->size);
}

static int ignore_undef_symbol(struct elf_info *info, const char *symname)
{
	/* ignore __this_module, it will be resolved shortly */
	if (strcmp(symname, "__this_module") == 0)
		return 1;
	/* ignore global offset table */
	if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
		return 1;
	if (info->hdr->e_machine == EM_PPC)
		/* Special register function linked on all modules during final link of .ko */
		if (strstarts(symname, "_restgpr_") ||
		    strstarts(symname, "_savegpr_") ||
		    strstarts(symname, "_rest32gpr_") ||
		    strstarts(symname, "_save32gpr_") ||
		    strstarts(symname, "_restvr_") ||
		    strstarts(symname, "_savevr_"))
			return 1;
	if (info->hdr->e_machine == EM_PPC64)
		/* Special register function linked on all modules during final link of .ko */
		if (strstarts(symname, "_restgpr0_") ||
		    strstarts(symname, "_savegpr0_") ||
		    strstarts(symname, "_restvr_") ||
		    strstarts(symname, "_savevr_") ||
		    strcmp(symname, ".TOC.") == 0)
			return 1;

	if (info->hdr->e_machine == EM_S390)
		/* Expoline thunks are linked on all kernel modules during final link of .ko */
		if (strstarts(symname, "__s390_indirect_jump_r"))
			return 1;
	/* Do not ignore this symbol */
	return 0;
}

static void handle_symbol(struct module *mod, struct elf_info *info,
			  const Elf_Sym *sym, const char *symname)
{
	switch (sym->st_shndx) {
	case SHN_COMMON:
		if (strstarts(symname, "__gnu_lto_")) {
			/* Should warn here, but modpost runs before the linker */
		} else
			warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
		break;
	case SHN_UNDEF:
		/* undefined symbol */
		if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
		    ELF_ST_BIND(sym->st_info) != STB_WEAK)
			break;
		if (ignore_undef_symbol(info, symname))
			break;
		if (info->hdr->e_machine == EM_SPARC ||
		    info->hdr->e_machine == EM_SPARCV9) {
			/* Ignore register directives. */
			if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
				break;
			if (symname[0] == '.') {
				char *munged = NOFAIL(strdup(symname));
				munged[0] = '_';
				munged[1] = toupper(munged[1]);
				symname = munged;
			}
		}

		sym_add_unresolved(symname, mod,
				   ELF_ST_BIND(sym->st_info) == STB_WEAK);
		break;
	default:
		if (strcmp(symname, "init_module") == 0)
			mod->has_init = true;
		if (strcmp(symname, "cleanup_module") == 0)
			mod->has_cleanup = true;
		break;
	}
}

/**
 * Parse tag=value strings from .modinfo section
 **/
static char *next_string(char *string, unsigned long *secsize)
{
	/* Skip non-zero chars */
	while (string[0]) {
		string++;
		if ((*secsize)-- <= 1)
			return NULL;
	}

	/* Skip any zero padding. */
	while (!string[0]) {
		string++;
		if ((*secsize)-- <= 1)
			return NULL;
	}
	return string;
}

static char *get_next_modinfo(struct elf_info *info, const char *tag,
			      char *prev)
{
	char *p;
	unsigned int taglen = strlen(tag);
	char *modinfo = info->modinfo;
	unsigned long size = info->modinfo_len;

	if (prev) {
		size -= prev - modinfo;
		modinfo = next_string(prev, &size);
	}

	for (p = modinfo; p; p = next_string(p, &size)) {
		if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
			return p + taglen + 1;
	}
	return NULL;
}

static char *get_modinfo(struct elf_info *info, const char *tag)

{
	return get_next_modinfo(info, tag, NULL);
}

static const char *sym_name(struct elf_info *elf, Elf_Sym *sym)
{
	if (sym)
		return elf->strtab + sym->st_name;
	else
		return "(unknown)";
}

/*
 * Check whether the 'string' argument matches one of the 'patterns',
 * an array of shell wildcard patterns (glob).
 *
 * Return true is there is a match.
 */
static bool match(const char *string, const char *const patterns[])
{
	const char *pattern;

	while ((pattern = *patterns++)) {
		if (!fnmatch(pattern, string, 0))
			return true;
	}

	return false;
}

/* useful to pass patterns to match() directly */
#define PATTERNS(...) \
	({ \
		static const char *const patterns[] = {__VA_ARGS__, NULL}; \
		patterns; \
	})

/* sections that we do not want to do full section mismatch check on */
static const char *const section_white_list[] =
{
	".comment*",
	".debug*",
	".zdebug*",		/* Compressed debug sections. */
	".GCC.command.line",	/* record-gcc-switches */
	".mdebug*",        /* alpha, score, mips etc. */
	".pdr",            /* alpha, score, mips etc. */
	".stab*",
	".note*",
	".got*",
	".toc*",
	".xt.prop",				 /* xtensa */
	".xt.lit",         /* xtensa */
	".arcextmap*",			/* arc */
	".gnu.linkonce.arcext*",	/* arc : modules */
	".cmem*",			/* EZchip */
	".fmt_slot*",			/* EZchip */
	".gnu.lto*",
	".discard.*",
	".llvm.call-graph-profile",	/* call graph */
	NULL
};

/*
 * This is used to find sections missing the SHF_ALLOC flag.
 * The cause of this is often a section specified in assembler
 * without "ax" / "aw".
 */
static void check_section(const char *modname, struct elf_info *elf,
			  Elf_Shdr *sechdr)
{
	const char *sec = sech_name(elf, sechdr);

	if (sechdr->sh_type == SHT_PROGBITS &&
	    !(sechdr->sh_flags & SHF_ALLOC) &&
	    !match(sec, section_white_list)) {
		warn("%s (%s): unexpected non-allocatable section.\n"
		     "Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
		     "Note that for example <linux/init.h> contains\n"
		     "section definitions for use in .S files.\n\n",
		     modname, sec);
	}
}



#define ALL_INIT_DATA_SECTIONS \
	".init.setup", ".init.rodata", ".meminit.rodata", \
	".init.data", ".meminit.data"
#define ALL_EXIT_DATA_SECTIONS \
	".exit.data", ".memexit.data"

#define ALL_INIT_TEXT_SECTIONS \
	".init.text", ".meminit.text"
#define ALL_EXIT_TEXT_SECTIONS \
	".exit.text", ".memexit.text"

#define ALL_PCI_INIT_SECTIONS	\
	".pci_fixup_early", ".pci_fixup_header", ".pci_fixup_final", \
	".pci_fixup_enable", ".pci_fixup_resume", \
	".pci_fixup_resume_early", ".pci_fixup_suspend"

#define ALL_XXXINIT_SECTIONS MEM_INIT_SECTIONS
#define ALL_XXXEXIT_SECTIONS MEM_EXIT_SECTIONS

#define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS
#define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS

#define DATA_SECTIONS ".data", ".data.rel"
#define TEXT_SECTIONS ".text", ".text.*", ".sched.text", \
		".kprobes.text", ".cpuidle.text", ".noinstr.text"
#define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \
		".fixup", ".entry.text", ".exception.text", \
		".coldtext", ".softirqentry.text"

#define INIT_SECTIONS      ".init.*"
#define MEM_INIT_SECTIONS  ".meminit.*"

#define EXIT_SECTIONS      ".exit.*"
#define MEM_EXIT_SECTIONS  ".memexit.*"

#define ALL_TEXT_SECTIONS  ALL_INIT_TEXT_SECTIONS, ALL_EXIT_TEXT_SECTIONS, \
		TEXT_SECTIONS, OTHER_TEXT_SECTIONS

enum mismatch {
	TEXT_TO_ANY_INIT,
	DATA_TO_ANY_INIT,
	TEXTDATA_TO_ANY_EXIT,
	XXXINIT_TO_SOME_INIT,
	XXXEXIT_TO_SOME_EXIT,
	ANY_INIT_TO_ANY_EXIT,
	ANY_EXIT_TO_ANY_INIT,
	EXTABLE_TO_NON_TEXT,
};

/**
 * Describe how to match sections on different criteria:
 *
 * @fromsec: Array of sections to be matched.
 *
 * @bad_tosec: Relocations applied to a section in @fromsec to a section in
 * this array is forbidden (black-list).  Can be empty.
 *
 * @good_tosec: Relocations applied to a section in @fromsec must be
 * targeting sections in this array (white-list).  Can be empty.
 *
 * @mismatch: Type of mismatch.
 */
struct sectioncheck {
	const char *fromsec[20];
	const char *bad_tosec[20];
	const char *good_tosec[20];
	enum mismatch mismatch;
};

static const struct sectioncheck sectioncheck[] = {
/* Do not reference init/exit code/data from
 * normal code and data
 */
{
	.fromsec = { TEXT_SECTIONS, NULL },
	.bad_tosec = { ALL_INIT_SECTIONS, NULL },
	.mismatch = TEXT_TO_ANY_INIT,
},
{
	.fromsec = { DATA_SECTIONS, NULL },
	.bad_tosec = { ALL_XXXINIT_SECTIONS, INIT_SECTIONS, NULL },
	.mismatch = DATA_TO_ANY_INIT,
},
{
	.fromsec = { TEXT_SECTIONS, DATA_SECTIONS, NULL },
	.bad_tosec = { ALL_EXIT_SECTIONS, NULL },
	.mismatch = TEXTDATA_TO_ANY_EXIT,
},
/* Do not reference init code/data from meminit code/data */
{
	.fromsec = { ALL_XXXINIT_SECTIONS, NULL },
	.bad_tosec = { INIT_SECTIONS, NULL },
	.mismatch = XXXINIT_TO_SOME_INIT,
},
/* Do not reference exit code/data from memexit code/data */
{
	.fromsec = { ALL_XXXEXIT_SECTIONS, NULL },
	.bad_tosec = { EXIT_SECTIONS, NULL },
	.mismatch = XXXEXIT_TO_SOME_EXIT,
},
/* Do not use exit code/data from init code */
{
	.fromsec = { ALL_INIT_SECTIONS, NULL },
	.bad_tosec = { ALL_EXIT_SECTIONS, NULL },
	.mismatch = ANY_INIT_TO_ANY_EXIT,
},
/* Do not use init code/data from exit code */
{
	.fromsec = { ALL_EXIT_SECTIONS, NULL },
	.bad_tosec = { ALL_INIT_SECTIONS, NULL },
	.mismatch = ANY_EXIT_TO_ANY_INIT,
},
{
	.fromsec = { ALL_PCI_INIT_SECTIONS, NULL },
	.bad_tosec = { INIT_SECTIONS, NULL },
	.mismatch = ANY_INIT_TO_ANY_EXIT,
},
{
	.fromsec = { "__ex_table", NULL },
	/* If you're adding any new black-listed sections in here, consider
	 * adding a special 'printer' for them in scripts/check_extable.
	 */
	.bad_tosec = { ".altinstr_replacement", NULL },
	.good_tosec = {ALL_TEXT_SECTIONS , NULL},
	.mismatch = EXTABLE_TO_NON_TEXT,
}
};

static const struct sectioncheck *section_mismatch(
		const char *fromsec, const char *tosec)
{
	int i;

	/*
	 * The target section could be the SHT_NUL section when we're
	 * handling relocations to un-resolved symbols, trying to match it
	 * doesn't make much sense and causes build failures on parisc
	 * architectures.
	 */
	if (*tosec == '\0')
		return NULL;

	for (i = 0; i < ARRAY_SIZE(sectioncheck); i++) {
		const struct sectioncheck *check = &sectioncheck[i];

		if (match(fromsec, check->fromsec)) {
			if (check->bad_tosec[0] && match(tosec, check->bad_tosec))
				return check;
			if (check->good_tosec[0] && !match(tosec, check->good_tosec))
				return check;
		}
	}
	return NULL;
}

/**
 * Whitelist to allow certain references to pass with no warning.
 *
 * Pattern 1:
 *   If a module parameter is declared __initdata and permissions=0
 *   then this is legal despite the warning generated.
 *   We cannot see value of permissions here, so just ignore
 *   this pattern.
 *   The pattern is identified by:
 *   tosec   = .init.data
 *   fromsec = .data*
 *   atsym   =__param*
 *
 * Pattern 1a:
 *   module_param_call() ops can refer to __init set function if permissions=0
 *   The pattern is identified by:
 *   tosec   = .init.text
 *   fromsec = .data*
 *   atsym   = __param_ops_*
 *
 * Pattern 3:
 *   Whitelist all references from .head.text to any init section
 *
 * Pattern 4:
 *   Some symbols belong to init section but still it is ok to reference
 *   these from non-init sections as these symbols don't have any memory
 *   allocated for them and symbol address and value are same. So even
 *   if init section is freed, its ok to reference those symbols.
 *   For ex. symbols marking the init section boundaries.
 *   This pattern is identified by
 *   refsymname = __init_begin, _sinittext, _einittext
 *
 * Pattern 5:
 *   GCC may optimize static inlines when fed constant arg(s) resulting
 *   in functions like cpumask_empty() -- generating an associated symbol
 *   cpumask_empty.constprop.3 that appears in the audit.  If the const that
 *   is passed in comes from __init, like say nmi_ipi_mask, we get a
 *   meaningless section warning.  May need to add isra symbols too...
 *   This pattern is identified by
 *   tosec   = init section
 *   fromsec = text section
 *   refsymname = *.constprop.*
 *
 **/
static int secref_whitelist(const char *fromsec, const char *fromsym,
			    const char *tosec, const char *tosym)
{
	/* Check for pattern 1 */
	if (match(tosec, PATTERNS(ALL_INIT_DATA_SECTIONS)) &&
	    match(fromsec, PATTERNS(DATA_SECTIONS)) &&
	    strstarts(fromsym, "__param"))
		return 0;

	/* Check for pattern 1a */
	if (strcmp(tosec, ".init.text") == 0 &&
	    match(fromsec, PATTERNS(DATA_SECTIONS)) &&
	    strstarts(fromsym, "__param_ops_"))
		return 0;

	/* symbols in data sections that may refer to any init/exit sections */
	if (match(fromsec, PATTERNS(DATA_SECTIONS)) &&
	    match(tosec, PATTERNS(ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS)) &&
	    match(fromsym, PATTERNS("*_template", // scsi uses *_template a lot
				    "*_timer", // arm uses ops structures named _timer a lot
				    "*_sht", // scsi also used *_sht to some extent
				    "*_ops",
				    "*_probe",
				    "*_probe_one",
				    "*_console")))
		return 0;

	/* symbols in data sections that may refer to meminit sections */
	if (match(fromsec, PATTERNS(DATA_SECTIONS)) &&
	    match(tosec, PATTERNS(ALL_XXXINIT_SECTIONS, ALL_XXXEXIT_SECTIONS)) &&
	    match(fromsym, PATTERNS("*driver")))
		return 0;

	/*
	 * symbols in data sections must not refer to .exit.*, but there are
	 * quite a few offenders, so hide these unless for W=1 builds until
	 * these are fixed.
	 */
	if (!extra_warn &&
	    match(fromsec, PATTERNS(DATA_SECTIONS)) &&
	    match(tosec, PATTERNS(EXIT_SECTIONS)) &&
	    match(fromsym, PATTERNS("*driver")))
		return 0;

	/* Check for pattern 3 */
	if (strstarts(fromsec, ".head.text") &&
	    match(tosec, PATTERNS(ALL_INIT_SECTIONS)))
		return 0;

	/* Check for pattern 4 */
	if (match(tosym, PATTERNS("__init_begin", "_sinittext", "_einittext")))
		return 0;

	/* Check for pattern 5 */
	if (match(fromsec, PATTERNS(ALL_TEXT_SECTIONS)) &&
	    match(tosec, PATTERNS(ALL_INIT_SECTIONS)) &&
	    match(fromsym, PATTERNS("*.constprop.*")))
		return 0;

	return 1;
}

/*
 * If there's no name there, ignore it; likewise, ignore it if it's
 * one of the magic symbols emitted used by current tools.
 *
 * Otherwise if find_symbols_between() returns those symbols, they'll
 * fail the whitelist tests and cause lots of false alarms ... fixable
 * only by merging __exit and __init sections into __text, bloating
 * the kernel (which is especially evil on embedded platforms).
 */
static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
{
	const char *name = elf->strtab + sym->st_name;

	if (!name || !strlen(name))
		return 0;
	return !is_mapping_symbol(name);
}

/* Look up the nearest symbol based on the section and the address */
static Elf_Sym *find_nearest_sym(struct elf_info *elf, Elf_Addr addr,
				 unsigned int secndx, bool allow_negative,
				 Elf_Addr min_distance)
{
	Elf_Sym *sym;
	Elf_Sym *near = NULL;
	Elf_Addr sym_addr, distance;
	bool is_arm = (elf->hdr->e_machine == EM_ARM);

	for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
		if (get_secindex(elf, sym) != secndx)
			continue;
		if (!is_valid_name(elf, sym))
			continue;

		sym_addr = sym->st_value;

		/*
		 * For ARM Thumb instruction, the bit 0 of st_value is set
		 * if the symbol is STT_FUNC type. Mask it to get the address.
		 */
		if (is_arm && ELF_ST_TYPE(sym->st_info) == STT_FUNC)
			 sym_addr &= ~1;

		if (addr >= sym_addr)
			distance = addr - sym_addr;
		else if (allow_negative)
			distance = sym_addr - addr;
		else
			continue;

		if (distance <= min_distance) {
			min_distance = distance;
			near = sym;
		}

		if (min_distance == 0)
			break;
	}
	return near;
}

static Elf_Sym *find_fromsym(struct elf_info *elf, Elf_Addr addr,
			     unsigned int secndx)
{
	return find_nearest_sym(elf, addr, secndx, false, ~0);
}

static Elf_Sym *find_tosym(struct elf_info *elf, Elf_Addr addr, Elf_Sym *sym)
{
	/* If the supplied symbol has a valid name, return it */
	if (is_valid_name(elf, sym))
		return sym;

	/*
	 * Strive to find a better symbol name, but the resulting name may not
	 * match the symbol referenced in the original code.
	 */
	return find_nearest_sym(elf, addr, get_secindex(elf, sym), true, 20);
}

static bool is_executable_section(struct elf_info *elf, unsigned int secndx)
{
	if (secndx >= elf->num_sections)
		return false;

	return (elf->sechdrs[secndx].sh_flags & SHF_EXECINSTR) != 0;
}

static void default_mismatch_handler(const char *modname, struct elf_info *elf,
				     const struct sectioncheck* const mismatch,
				     Elf_Sym *tsym,
				     unsigned int fsecndx, const char *fromsec, Elf_Addr faddr,
				     const char *tosec, Elf_Addr taddr)
{
	Elf_Sym *from;
	const char *tosym;
	const char *fromsym;

	from = find_fromsym(elf, faddr, fsecndx);
	fromsym = sym_name(elf, from);

	tsym = find_tosym(elf, taddr, tsym);
	tosym = sym_name(elf, tsym);

	/* check whitelist - we may ignore it */
	if (!secref_whitelist(fromsec, fromsym, tosec, tosym))
		return;

	sec_mismatch_count++;

	warn("%s: section mismatch in reference: %s+0x%x (section: %s) -> %s (section: %s)\n",
	     modname, fromsym, (unsigned int)(faddr - from->st_value), fromsec, tosym, tosec);

	if (mismatch->mismatch == EXTABLE_TO_NON_TEXT) {
		if (match(tosec, mismatch->bad_tosec))
			fatal("The relocation at %s+0x%lx references\n"
			      "section \"%s\" which is black-listed.\n"
			      "Something is seriously wrong and should be fixed.\n"
			      "You might get more information about where this is\n"
			      "coming from by using scripts/check_extable.sh %s\n",
			      fromsec, (long)faddr, tosec, modname);
		else if (is_executable_section(elf, get_secindex(elf, tsym)))
			warn("The relocation at %s+0x%lx references\n"
			     "section \"%s\" which is not in the list of\n"
			     "authorized sections.  If you're adding a new section\n"
			     "and/or if this reference is valid, add \"%s\" to the\n"
			     "list of authorized sections to jump to on fault.\n"
			     "This can be achieved by adding \"%s\" to\n"
			     "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n",
			     fromsec, (long)faddr, tosec, tosec, tosec);
		else
			error("%s+0x%lx references non-executable section '%s'\n",
			      fromsec, (long)faddr, tosec);
	}
}

static void check_export_symbol(struct module *mod, struct elf_info *elf,
				Elf_Addr faddr, const char *secname,
				Elf_Sym *sym)
{
	static const char *prefix = "__export_symbol_";
	const char *label_name, *name, *data;
	Elf_Sym *label;
	struct symbol *s;
	bool is_gpl;

	label = find_fromsym(elf, faddr, elf->export_symbol_secndx);
	label_name = sym_name(elf, label);

	if (!strstarts(label_name, prefix)) {
		error("%s: .export_symbol section contains strange symbol '%s'\n",
		      mod->name, label_name);
		return;
	}

	if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
	    ELF_ST_BIND(sym->st_info) != STB_WEAK) {
		error("%s: local symbol '%s' was exported\n", mod->name,
		      label_name + strlen(prefix));
		return;
	}

	name = sym_name(elf, sym);
	if (strcmp(label_name + strlen(prefix), name)) {
		error("%s: .export_symbol section references '%s', but it does not seem to be an export symbol\n",
		      mod->name, name);
		return;
	}

	data = sym_get_data(elf, label);	/* license */
	if (!strcmp(data, "GPL")) {
		is_gpl = true;
	} else if (!strcmp(data, "")) {
		is_gpl = false;
	} else {
		error("%s: unknown license '%s' was specified for '%s'\n",
		      mod->name, data, name);
		return;
	}

	data += strlen(data) + 1;	/* namespace */
	s = sym_add_exported(name, mod, is_gpl, data);

	/*
	 * We need to be aware whether we are exporting a function or
	 * a data on some architectures.
	 */
	s->is_func = (ELF_ST_TYPE(sym->st_info) == STT_FUNC);

	/*
	 * For parisc64, symbols prefixed $$ from the library have the symbol type
	 * STT_LOPROC. They should be handled as functions too.
	 */
	if (elf->hdr->e_ident[EI_CLASS] == ELFCLASS64 &&
	    elf->hdr->e_machine == EM_PARISC &&
	    ELF_ST_TYPE(sym->st_info) == STT_LOPROC)
		s->is_func = true;

	if (match(secname, PATTERNS(INIT_SECTIONS)))
		warn("%s: %s: EXPORT_SYMBOL used for init symbol. Remove __init or EXPORT_SYMBOL.\n",
		     mod->name, name);
	else if (match(secname, PATTERNS(EXIT_SECTIONS)))
		warn("%s: %s: EXPORT_SYMBOL used for exit symbol. Remove __exit or EXPORT_SYMBOL.\n",
		     mod->name, name);
}

static void check_section_mismatch(struct module *mod, struct elf_info *elf,
				   Elf_Sym *sym,
				   unsigned int fsecndx, const char *fromsec,
				   Elf_Addr faddr, Elf_Addr taddr)
{
	const char *tosec = sec_name(elf, get_secindex(elf, sym));
	const struct sectioncheck *mismatch;

	if (module_enabled && elf->export_symbol_secndx == fsecndx) {
		check_export_symbol(mod, elf, faddr, tosec, sym);
		return;
	}

	mismatch = section_mismatch(fromsec, tosec);
	if (!mismatch)
		return;

	default_mismatch_handler(mod->name, elf, mismatch, sym,
				 fsecndx, fromsec, faddr,
				 tosec, taddr);
}

static Elf_Addr addend_386_rel(uint32_t *location, unsigned int r_type)
{
	switch (r_type) {
	case R_386_32:
		return TO_NATIVE(*location);
	case R_386_PC32:
		return TO_NATIVE(*location) + 4;
	}

	return (Elf_Addr)(-1);
}

#ifndef R_ARM_CALL
#define R_ARM_CALL	28
#endif
#ifndef R_ARM_JUMP24
#define R_ARM_JUMP24	29
#endif

#ifndef	R_ARM_THM_CALL
#define	R_ARM_THM_CALL		10
#endif
#ifndef	R_ARM_THM_JUMP24
#define	R_ARM_THM_JUMP24	30
#endif

#ifndef R_ARM_MOVW_ABS_NC
#define R_ARM_MOVW_ABS_NC	43
#endif

#ifndef R_ARM_MOVT_ABS
#define R_ARM_MOVT_ABS		44
#endif

#ifndef R_ARM_THM_MOVW_ABS_NC
#define R_ARM_THM_MOVW_ABS_NC	47
#endif

#ifndef R_ARM_THM_MOVT_ABS
#define R_ARM_THM_MOVT_ABS	48
#endif

#ifndef	R_ARM_THM_JUMP19
#define	R_ARM_THM_JUMP19	51
#endif

static int32_t sign_extend32(int32_t value, int index)
{
	uint8_t shift = 31 - index;

	return (int32_t)(value << shift) >> shift;
}

static Elf_Addr addend_arm_rel(void *loc, Elf_Sym *sym, unsigned int r_type)
{
	uint32_t inst, upper, lower, sign, j1, j2;
	int32_t offset;

	switch (r_type) {
	case R_ARM_ABS32:
	case R_ARM_REL32:
		inst = TO_NATIVE(*(uint32_t *)loc);
		return inst + sym->st_value;
	case R_ARM_MOVW_ABS_NC:
	case R_ARM_MOVT_ABS:
		inst = TO_NATIVE(*(uint32_t *)loc);
		offset = sign_extend32(((inst & 0xf0000) >> 4) | (inst & 0xfff),
				       15);
		return offset + sym->st_value;
	case R_ARM_PC24:
	case R_ARM_CALL:
	case R_ARM_JUMP24:
		inst = TO_NATIVE(*(uint32_t *)loc);
		offset = sign_extend32((inst & 0x00ffffff) << 2, 25);
		return offset + sym->st_value + 8;
	case R_ARM_THM_MOVW_ABS_NC:
	case R_ARM_THM_MOVT_ABS:
		upper = TO_NATIVE(*(uint16_t *)loc);
		lower = TO_NATIVE(*((uint16_t *)loc + 1));
		offset = sign_extend32(((upper & 0x000f) << 12) |
				       ((upper & 0x0400) << 1) |
				       ((lower & 0x7000) >> 4) |
				       (lower & 0x00ff),
				       15);
		return offset + sym->st_value;
	case R_ARM_THM_JUMP19:
		/*
		 * Encoding T3:
		 * S     = upper[10]
		 * imm6  = upper[5:0]
		 * J1    = lower[13]
		 * J2    = lower[11]
		 * imm11 = lower[10:0]
		 * imm32 = SignExtend(S:J2:J1:imm6:imm11:'0')
		 */
		upper = TO_NATIVE(*(uint16_t *)loc);
		lower = TO_NATIVE(*((uint16_t *)loc + 1));

		sign = (upper >> 10) & 1;
		j1 = (lower >> 13) & 1;
		j2 = (lower >> 11) & 1;
		offset = sign_extend32((sign << 20) | (j2 << 19) | (j1 << 18) |
				       ((upper & 0x03f) << 12) |
				       ((lower & 0x07ff) << 1),
				       20);
		return offset + sym->st_value + 4;
	case R_ARM_THM_CALL:
	case R_ARM_THM_JUMP24:
		/*
		 * Encoding T4:
		 * S     = upper[10]
		 * imm10 = upper[9:0]
		 * J1    = lower[13]
		 * J2    = lower[11]
		 * imm11 = lower[10:0]
		 * I1    = NOT(J1 XOR S)
		 * I2    = NOT(J2 XOR S)
		 * imm32 = SignExtend(S:I1:I2:imm10:imm11:'0')
		 */
		upper = TO_NATIVE(*(uint16_t *)loc);
		lower = TO_NATIVE(*((uint16_t *)loc + 1));

		sign = (upper >> 10) & 1;
		j1 = (lower >> 13) & 1;
		j2 = (lower >> 11) & 1;
		offset = sign_extend32((sign << 24) |
				       ((~(j1 ^ sign) & 1) << 23) |
				       ((~(j2 ^ sign) & 1) << 22) |
				       ((upper & 0x03ff) << 12) |
				       ((lower & 0x07ff) << 1),
				       24);
		return offset + sym->st_value + 4;
	}

	return (Elf_Addr)(-1);
}

static Elf_Addr addend_mips_rel(uint32_t *location, unsigned int r_type)
{
	uint32_t inst;

	inst = TO_NATIVE(*location);
	switch (r_type) {
	case R_MIPS_LO16:
		return inst & 0xffff;
	case R_MIPS_26:
		return (inst & 0x03ffffff) << 2;
	case R_MIPS_32:
		return inst;
	}
	return (Elf_Addr)(-1);
}

#ifndef EM_RISCV
#define EM_RISCV		243
#endif

#ifndef R_RISCV_SUB32
#define R_RISCV_SUB32		39
#endif

#ifndef EM_LOONGARCH
#define EM_LOONGARCH		258
#endif

#ifndef R_LARCH_SUB32
#define R_LARCH_SUB32		55
#endif

static void get_rel_type_and_sym(struct elf_info *elf, uint64_t r_info,
				 unsigned int *r_type, unsigned int *r_sym)
{
	typedef struct {
		Elf64_Word    r_sym;	/* Symbol index */
		unsigned char r_ssym;	/* Special symbol for 2nd relocation */
		unsigned char r_type3;	/* 3rd relocation type */
		unsigned char r_type2;	/* 2nd relocation type */
		unsigned char r_type;	/* 1st relocation type */
	} Elf64_Mips_R_Info;

	bool is_64bit = (elf->hdr->e_ident[EI_CLASS] == ELFCLASS64);

	if (elf->hdr->e_machine == EM_MIPS && is_64bit) {
		Elf64_Mips_R_Info *mips64_r_info = (void *)&r_info;

		*r_type = mips64_r_info->r_type;
		*r_sym = TO_NATIVE(mips64_r_info->r_sym);
		return;
	}

	if (is_64bit) {
		Elf64_Xword r_info64 = r_info;

		r_info = TO_NATIVE(r_info64);
	} else {
		Elf32_Word r_info32 = r_info;

		r_info = TO_NATIVE(r_info32);
	}

	*r_type = ELF_R_TYPE(r_info);
	*r_sym = ELF_R_SYM(r_info);
}

static void section_rela(struct module *mod, struct elf_info *elf,
			 Elf_Shdr *sechdr)
{
	Elf_Rela *rela;
	unsigned int fsecndx = sechdr->sh_info;
	const char *fromsec = sec_name(elf, fsecndx);
	Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset;
	Elf_Rela *stop  = (void *)start + sechdr->sh_size;

	/* if from section (name) is know good then skip it */
	if (match(fromsec, section_white_list))
		return;

	for (rela = start; rela < stop; rela++) {
		Elf_Addr taddr, r_offset;
		unsigned int r_type, r_sym;

		r_offset = TO_NATIVE(rela->r_offset);
		get_rel_type_and_sym(elf, rela->r_info, &r_type, &r_sym);

		taddr = TO_NATIVE(rela->r_addend);

		switch (elf->hdr->e_machine) {
		case EM_RISCV:
			if (!strcmp("__ex_table", fromsec) &&
			    r_type == R_RISCV_SUB32)
				continue;
			break;
		case EM_LOONGARCH:
			if (!strcmp("__ex_table", fromsec) &&
			    r_type == R_LARCH_SUB32)
				continue;
			break;
		}

		check_section_mismatch(mod, elf, elf->symtab_start + r_sym,
				       fsecndx, fromsec, r_offset, taddr);
	}
}

static void section_rel(struct module *mod, struct elf_info *elf,
			Elf_Shdr *sechdr)
{
	Elf_Rel *rel;
	unsigned int fsecndx = sechdr->sh_info;
	const char *fromsec = sec_name(elf, fsecndx);
	Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset;
	Elf_Rel *stop  = (void *)start + sechdr->sh_size;

	/* if from section (name) is know good then skip it */
	if (match(fromsec, section_white_list))
		return;

	for (rel = start; rel < stop; rel++) {
		Elf_Sym *tsym;
		Elf_Addr taddr = 0, r_offset;
		unsigned int r_type, r_sym;
		void *loc;

		r_offset = TO_NATIVE(rel->r_offset);
		get_rel_type_and_sym(elf, rel->r_info, &r_type, &r_sym);

		loc = sym_get_data_by_offset(elf, fsecndx, r_offset);
		tsym = elf->symtab_start + r_sym;

		switch (elf->hdr->e_machine) {
		case EM_386:
			taddr = addend_386_rel(loc, r_type);
			break;
		case EM_ARM:
			taddr = addend_arm_rel(loc, tsym, r_type);
			break;
		case EM_MIPS:
			taddr = addend_mips_rel(loc, r_type);
			break;
		default:
			fatal("Please add code to calculate addend for this architecture\n");
		}

		check_section_mismatch(mod, elf, tsym,
				       fsecndx, fromsec, r_offset, taddr);
	}
}

/**
 * A module includes a number of sections that are discarded
 * either when loaded or when used as built-in.
 * For loaded modules all functions marked __init and all data
 * marked __initdata will be discarded when the module has been initialized.
 * Likewise for modules used built-in the sections marked __exit
 * are discarded because __exit marked function are supposed to be called
 * only when a module is unloaded which never happens for built-in modules.
 * The check_sec_ref() function traverses all relocation records
 * to find all references to a section that reference a section that will
 * be discarded and warns about it.
 **/
static void check_sec_ref(struct module *mod, struct elf_info *elf)
{
	int i;
	Elf_Shdr *sechdrs = elf->sechdrs;

	/* Walk through all sections */
	for (i = 0; i < elf->num_sections; i++) {
		check_section(mod->name, elf, &elf->sechdrs[i]);
		/* We want to process only relocation sections and not .init */
		if (sechdrs[i].sh_type == SHT_RELA)
			section_rela(mod, elf, &elf->sechdrs[i]);
		else if (sechdrs[i].sh_type == SHT_REL)
			section_rel(mod, elf, &elf->sechdrs[i]);
	}
}

static char *remove_dot(char *s)
{
	size_t n = strcspn(s, ".");

	if (n && s[n]) {
		size_t m = strspn(s + n + 1, "0123456789");
		if (m && (s[n + m + 1] == '.' || s[n + m + 1] == 0))
			s[n] = 0;
	}
	return s;
}

/*
 * The CRCs are recorded in .*.cmd files in the form of:
 * #SYMVER <name> <crc>
 */
static void extract_crcs_for_object(const char *object, struct module *mod)
{
	char cmd_file[PATH_MAX];
	char *buf, *p;
	const char *base;
	int dirlen, ret;

	base = strrchr(object, '/');
	if (base) {
		base++;
		dirlen = base - object;
	} else {
		dirlen = 0;
		base = object;
	}

	ret = snprintf(cmd_file, sizeof(cmd_file), "%.*s.%s.cmd",
		       dirlen, object, base);
	if (ret >= sizeof(cmd_file)) {
		error("%s: too long path was truncated\n", cmd_file);
		return;
	}

	buf = read_text_file(cmd_file);
	p = buf;

	while ((p = strstr(p, "\n#SYMVER "))) {
		char *name;
		size_t namelen;
		unsigned int crc;
		struct symbol *sym;

		name = p + strlen("\n#SYMVER ");

		p = strchr(name, ' ');
		if (!p)
			break;

		namelen = p - name;
		p++;

		if (!isdigit(*p))
			continue;	/* skip this line */

		crc = strtoul(p, &p, 0);
		if (*p != '\n')
			continue;	/* skip this line */

		name[namelen] = '\0';

		/*
		 * sym_find_with_module() may return NULL here.
		 * It typically occurs when CONFIG_TRIM_UNUSED_KSYMS=y.
		 * Since commit e1327a127703, genksyms calculates CRCs of all
		 * symbols, including trimmed ones. Ignore orphan CRCs.
		 */
		sym = sym_find_with_module(name, mod);
		if (sym)
			sym_set_crc(sym, crc);
	}

	free(buf);
}

/*
 * The symbol versions (CRC) are recorded in the .*.cmd files.
 * Parse them to retrieve CRCs for the current module.
 */
static void mod_set_crcs(struct module *mod)
{
	char objlist[PATH_MAX];
	char *buf, *p, *obj;
	int ret;

	if (mod->is_vmlinux) {
		strcpy(objlist, ".vmlinux.objs");
	} else {
		/* objects for a module are listed in the *.mod file. */
		ret = snprintf(objlist, sizeof(objlist), "%s.mod", mod->name);
		if (ret >= sizeof(objlist)) {
			error("%s: too long path was truncated\n", objlist);
			return;
		}
	}

	buf = read_text_file(objlist);
	p = buf;

	while ((obj = strsep(&p, "\n")) && obj[0])
		extract_crcs_for_object(obj, mod);

	free(buf);
}

static void read_symbols(const char *modname)
{
	const char *symname;
	char *version;
	char *license;
	char *namespace;
	struct module *mod;
	struct elf_info info = { };
	Elf_Sym *sym;

	if (!parse_elf(&info, modname))
		return;

	if (!strends(modname, ".o")) {
		error("%s: filename must be suffixed with .o\n", modname);
		return;
	}

	/* strip trailing .o */
	mod = new_module(modname, strlen(modname) - strlen(".o"));

	if (!mod->is_vmlinux) {
		license = get_modinfo(&info, "license");
		if (!license)
			error("missing MODULE_LICENSE() in %s\n", modname);
		while (license) {
			if (!license_is_gpl_compatible(license)) {
				mod->is_gpl_compatible = false;
				break;
			}
			license = get_next_modinfo(&info, "license", license);
		}

		namespace = get_modinfo(&info, "import_ns");
		while (namespace) {
			add_namespace(&mod->imported_namespaces, namespace);
			namespace = get_next_modinfo(&info, "import_ns",
						     namespace);
		}
	}

	if (extra_warn && !get_modinfo(&info, "description"))
		warn("missing MODULE_DESCRIPTION() in %s\n", modname);
	for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
		symname = remove_dot(info.strtab + sym->st_name);

		handle_symbol(mod, &info, sym, symname);
		handle_moddevtable(mod, &info, sym, symname);
	}

	check_sec_ref(mod, &info);

	if (!mod->is_vmlinux) {
		version = get_modinfo(&info, "version");
		if (version || all_versions)
			get_src_version(mod->name, mod->srcversion,
					sizeof(mod->srcversion) - 1);
	}

	parse_elf_finish(&info);

	if (modversions) {
		/*
		 * Our trick to get versioning for module struct etc. - it's
		 * never passed as an argument to an exported function, so
		 * the automatic versioning doesn't pick it up, but it's really
		 * important anyhow.
		 */
		sym_add_unresolved("module_layout", mod, false);

		mod_set_crcs(mod);
	}
}

static void read_symbols_from_files(const char *filename)
{
	FILE *in = stdin;
	char fname[PATH_MAX];

	in = fopen(filename, "r");
	if (!in)
		fatal("Can't open filenames file %s: %m", filename);

	while (fgets(fname, PATH_MAX, in) != NULL) {
		if (strends(fname, "\n"))
			fname[strlen(fname)-1] = '\0';
		read_symbols(fname);
	}

	fclose(in);
}

#define SZ 500

/* We first write the generated file into memory using the
 * following helper, then compare to the file on disk and
 * only update the later if anything changed */

void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
						      const char *fmt, ...)
{
	char tmp[SZ];
	int len;
	va_list ap;

	va_start(ap, fmt);
	len = vsnprintf(tmp, SZ, fmt, ap);
	buf_write(buf, tmp, len);
	va_end(ap);
}

void buf_write(struct buffer *buf, const char *s, int len)
{
	if (buf->size - buf->pos < len) {
		buf->size += len + SZ;
		buf->p = NOFAIL(realloc(buf->p, buf->size));
	}
	strncpy(buf->p + buf->pos, s, len);
	buf->pos += len;
}

static void check_exports(struct module *mod)
{
	struct symbol *s, *exp;

	list_for_each_entry(s, &mod->unresolved_symbols, list) {
		const char *basename;
		exp = find_symbol(s->name);
		if (!exp) {
			if (!s->weak && nr_unresolved++ < MAX_UNRESOLVED_REPORTS)
				modpost_log(warn_unresolved ? LOG_WARN : LOG_ERROR,
					    "\"%s\" [%s.ko] undefined!\n",
					    s->name, mod->name);
			continue;
		}
		if (exp->module == mod) {
			error("\"%s\" [%s.ko] was exported without definition\n",
			      s->name, mod->name);
			continue;
		}

		exp->used = true;
		s->module = exp->module;
		s->crc_valid = exp->crc_valid;
		s->crc = exp->crc;

		basename = strrchr(mod->name, '/');
		if (basename)
			basename++;
		else
			basename = mod->name;

		if (!contains_namespace(&mod->imported_namespaces, exp->namespace)) {
			modpost_log(allow_missing_ns_imports ? LOG_WARN : LOG_ERROR,
				    "module %s uses symbol %s from namespace %s, but does not import it.\n",
				    basename, exp->name, exp->namespace);
			add_namespace(&mod->missing_namespaces, exp->namespace);
		}

		if (!mod->is_gpl_compatible && exp->is_gpl_only)
			error("GPL-incompatible module %s.ko uses GPL-only symbol '%s'\n",
			      basename, exp->name);
	}
}

static void handle_white_list_exports(const char *white_list)
{
	char *buf, *p, *name;

	buf = read_text_file(white_list);
	p = buf;

	while ((name = strsep(&p, "\n"))) {
		struct symbol *sym = find_symbol(name);

		if (sym)
			sym->used = true;
	}

	free(buf);
}

static void check_modname_len(struct module *mod)
{
	const char *mod_name;

	mod_name = strrchr(mod->name, '/');
	if (mod_name == NULL)
		mod_name = mod->name;
	else
		mod_name++;
	if (strlen(mod_name) >= MODULE_NAME_LEN)
		error("module name is too long [%s.ko]\n", mod->name);
}

/**
 * Header for the generated file
 **/
static void add_header(struct buffer *b, struct module *mod)
{
	buf_printf(b, "#include <linux/module.h>\n");
	/*
	 * Include build-salt.h after module.h in order to
	 * inherit the definitions.
	 */
	buf_printf(b, "#define INCLUDE_VERMAGIC\n");
	buf_printf(b, "#include <linux/build-salt.h>\n");
	buf_printf(b, "#include <linux/elfnote-lto.h>\n");
	buf_printf(b, "#include <linux/export-internal.h>\n");
	buf_printf(b, "#include <linux/vermagic.h>\n");
	buf_printf(b, "#include <linux/compiler.h>\n");
	buf_printf(b, "\n");
	buf_printf(b, "#ifdef CONFIG_UNWINDER_ORC\n");
	buf_printf(b, "#include <asm/orc_header.h>\n");
	buf_printf(b, "ORC_HEADER;\n");
	buf_printf(b, "#endif\n");
	buf_printf(b, "\n");
	buf_printf(b, "BUILD_SALT;\n");
	buf_printf(b, "BUILD_LTO_INFO;\n");
	buf_printf(b, "\n");
	buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
	buf_printf(b, "MODULE_INFO(name, KBUILD_MODNAME);\n");
	buf_printf(b, "\n");
	buf_printf(b, "__visible struct module __this_module\n");
	buf_printf(b, "__section(\".gnu.linkonce.this_module\") = {\n");
	buf_printf(b, "\t.name = KBUILD_MODNAME,\n");
	if (mod->has_init)
		buf_printf(b, "\t.init = init_module,\n");
	if (mod->has_cleanup)
		buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
			      "\t.exit = cleanup_module,\n"
			      "#endif\n");
	buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n");
	buf_printf(b, "};\n");

	if (!external_module)
		buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n");

	buf_printf(b,
		   "\n"
		   "#ifdef CONFIG_RETPOLINE\n"
		   "MODULE_INFO(retpoline, \"Y\");\n"
		   "#endif\n");

	if (strstarts(mod->name, "drivers/staging"))
		buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");

	if (strstarts(mod->name, "tools/testing"))
		buf_printf(b, "\nMODULE_INFO(test, \"Y\");\n");
}

static void add_exported_symbols(struct buffer *buf, struct module *mod)
{
	struct symbol *sym;

	/* generate struct for exported symbols */
	buf_printf(buf, "\n");
	list_for_each_entry(sym, &mod->exported_symbols, list) {
		if (trim_unused_exports && !sym->used)
			continue;

		buf_printf(buf, "KSYMTAB_%s(%s, \"%s\", \"%s\");\n",
			   sym->is_func ? "FUNC" : "DATA", sym->name,
			   sym->is_gpl_only ? "_gpl" : "", sym->namespace);
	}

	if (!modversions)
		return;

	/* record CRCs for exported symbols */
	buf_printf(buf, "\n");
	list_for_each_entry(sym, &mod->exported_symbols, list) {
		if (trim_unused_exports && !sym->used)
			continue;

		if (!sym->crc_valid)
			warn("EXPORT symbol \"%s\" [%s%s] version generation failed, symbol will not be versioned.\n"
			     "Is \"%s\" prototyped in <asm/asm-prototypes.h>?\n",
			     sym->name, mod->name, mod->is_vmlinux ? "" : ".ko",
			     sym->name);

		buf_printf(buf, "SYMBOL_CRC(%s, 0x%08x, \"%s\");\n",
			   sym->name, sym->crc, sym->is_gpl_only ? "_gpl" : "");
	}
}

/**
 * Record CRCs for unresolved symbols
 **/
static void add_versions(struct buffer *b, struct module *mod)
{
	struct symbol *s;

	if (!modversions)
		return;

	buf_printf(b, "\n");
	buf_printf(b, "static const struct modversion_info ____versions[]\n");
	buf_printf(b, "__used __section(\"__versions\") = {\n");

	list_for_each_entry(s, &mod->unresolved_symbols, list) {
		if (!s->module)
			continue;
		if (!s->crc_valid) {
			warn("\"%s\" [%s.ko] has no CRC!\n",
				s->name, mod->name);
			continue;
		}
		if (strlen(s->name) >= MODULE_NAME_LEN) {
			error("too long symbol \"%s\" [%s.ko]\n",
			      s->name, mod->name);
			break;
		}
		buf_printf(b, "\t{ %#8x, \"%s\" },\n",
			   s->crc, s->name);
	}

	buf_printf(b, "};\n");
}

static void add_depends(struct buffer *b, struct module *mod)
{
	struct symbol *s;
	int first = 1;

	/* Clear ->seen flag of modules that own symbols needed by this. */
	list_for_each_entry(s, &mod->unresolved_symbols, list) {
		if (s->module)
			s->module->seen = s->module->is_vmlinux;
	}

	buf_printf(b, "\n");
	buf_printf(b, "MODULE_INFO(depends, \"");
	list_for_each_entry(s, &mod->unresolved_symbols, list) {
		const char *p;
		if (!s->module)
			continue;

		if (s->module->seen)
			continue;

		s->module->seen = true;
		p = strrchr(s->module->name, '/');
		if (p)
			p++;
		else
			p = s->module->name;
		buf_printf(b, "%s%s", first ? "" : ",", p);
		first = 0;
	}
	buf_printf(b, "\");\n");
}

static void add_srcversion(struct buffer *b, struct module *mod)
{
	if (mod->srcversion[0]) {
		buf_printf(b, "\n");
		buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
			   mod->srcversion);
	}
}

static void write_buf(struct buffer *b, const char *fname)
{
	FILE *file;

	if (error_occurred)
		return;

	file = fopen(fname, "w");
	if (!file) {
		perror(fname);
		exit(1);
	}
	if (fwrite(b->p, 1, b->pos, file) != b->pos) {
		perror(fname);
		exit(1);
	}
	if (fclose(file) != 0) {
		perror(fname);
		exit(1);
	}
}

static void write_if_changed(struct buffer *b, const char *fname)
{
	char *tmp;
	FILE *file;
	struct stat st;

	file = fopen(fname, "r");
	if (!file)
		goto write;

	if (fstat(fileno(file), &st) < 0)
		goto close_write;

	if (st.st_size != b->pos)
		goto close_write;

	tmp = NOFAIL(malloc(b->pos));
	if (fread(tmp, 1, b->pos, file) != b->pos)
		goto free_write;

	if (memcmp(tmp, b->p, b->pos) != 0)
		goto free_write;

	free(tmp);
	fclose(file);
	return;

 free_write:
	free(tmp);
 close_write:
	fclose(file);
 write:
	write_buf(b, fname);
}

static void write_vmlinux_export_c_file(struct module *mod)
{
	struct buffer buf = { };

	buf_printf(&buf,
		   "#include <linux/export-internal.h>\n");

	add_exported_symbols(&buf, mod);
	write_if_changed(&buf, ".vmlinux.export.c");
	free(buf.p);
}

/* do sanity checks, and generate *.mod.c file */
static void write_mod_c_file(struct module *mod)
{
	struct buffer buf = { };
	char fname[PATH_MAX];
	int ret;

	add_header(&buf, mod);
	add_exported_symbols(&buf, mod);
	add_versions(&buf, mod);
	add_depends(&buf, mod);
	add_moddevtable(&buf, mod);
	add_srcversion(&buf, mod);

	ret = snprintf(fname, sizeof(fname), "%s.mod.c", mod->name);
	if (ret >= sizeof(fname)) {
		error("%s: too long path was truncated\n", fname);
		goto free;
	}

	write_if_changed(&buf, fname);

free:
	free(buf.p);
}

/* parse Module.symvers file. line format:
 * 0x12345678<tab>symbol<tab>module<tab>export<tab>namespace
 **/
static void read_dump(const char *fname)
{
	char *buf, *pos, *line;

	buf = read_text_file(fname);
	if (!buf)
		/* No symbol versions, silently ignore */
		return;

	pos = buf;

	while ((line = get_line(&pos))) {
		char *symname, *namespace, *modname, *d, *export;
		unsigned int crc;
		struct module *mod;
		struct symbol *s;
		bool gpl_only;

		if (!(symname = strchr(line, '\t')))
			goto fail;
		*symname++ = '\0';
		if (!(modname = strchr(symname, '\t')))
			goto fail;
		*modname++ = '\0';
		if (!(export = strchr(modname, '\t')))
			goto fail;
		*export++ = '\0';
		if (!(namespace = strchr(export, '\t')))
			goto fail;
		*namespace++ = '\0';

		crc = strtoul(line, &d, 16);
		if (*symname == '\0' || *modname == '\0' || *d != '\0')
			goto fail;

		if (!strcmp(export, "EXPORT_SYMBOL_GPL")) {
			gpl_only = true;
		} else if (!strcmp(export, "EXPORT_SYMBOL")) {
			gpl_only = false;
		} else {
			error("%s: unknown license %s. skip", symname, export);
			continue;
		}

		mod = find_module(modname);
		if (!mod) {
			mod = new_module(modname, strlen(modname));
			mod->from_dump = true;
		}
		s = sym_add_exported(symname, mod, gpl_only, namespace);
		sym_set_crc(s, crc);
	}
	free(buf);
	return;
fail:
	free(buf);
	fatal("parse error in symbol dump file\n");
}

static void write_dump(const char *fname)
{
	struct buffer buf = { };
	struct module *mod;
	struct symbol *sym;

	list_for_each_entry(mod, &modules, list) {
		if (mod->from_dump)
			continue;
		list_for_each_entry(sym, &mod->exported_symbols, list) {
			if (trim_unused_exports && !sym->used)
				continue;

			buf_printf(&buf, "0x%08x\t%s\t%s\tEXPORT_SYMBOL%s\t%s\n",
				   sym->crc, sym->name, mod->name,
				   sym->is_gpl_only ? "_GPL" : "",
				   sym->namespace);
		}
	}
	write_buf(&buf, fname);
	free(buf.p);
}

static void write_namespace_deps_files(const char *fname)
{
	struct module *mod;
	struct namespace_list *ns;
	struct buffer ns_deps_buf = {};

	list_for_each_entry(mod, &modules, list) {

		if (mod->from_dump || list_empty(&mod->missing_namespaces))
			continue;

		buf_printf(&ns_deps_buf, "%s.ko:", mod->name);

		list_for_each_entry(ns, &mod->missing_namespaces, list)
			buf_printf(&ns_deps_buf, " %s", ns->namespace);

		buf_printf(&ns_deps_buf, "\n");
	}

	write_if_changed(&ns_deps_buf, fname);
	free(ns_deps_buf.p);
}

struct dump_list {
	struct list_head list;
	const char *file;
};

int main(int argc, char **argv)
{
	struct module *mod;
	char *missing_namespace_deps = NULL;
	char *unused_exports_white_list = NULL;
	char *dump_write = NULL, *files_source = NULL;
	int opt;
	LIST_HEAD(dump_lists);
	struct dump_list *dl, *dl2;

	while ((opt = getopt(argc, argv, "ei:MmnT:to:au:WwENd:")) != -1) {
		switch (opt) {
		case 'e':
			external_module = true;
			break;
		case 'i':
			dl = NOFAIL(malloc(sizeof(*dl)));
			dl->file = optarg;
			list_add_tail(&dl->list, &dump_lists);
			break;
		case 'M':
			module_enabled = true;
			break;
		case 'm':
			modversions = true;
			break;
		case 'n':
			ignore_missing_files = true;
			break;
		case 'o':
			dump_write = optarg;
			break;
		case 'a':
			all_versions = true;
			break;
		case 'T':
			files_source = optarg;
			break;
		case 't':
			trim_unused_exports = true;
			break;
		case 'u':
			unused_exports_white_list = optarg;
			break;
		case 'W':
			extra_warn = true;
			break;
		case 'w':
			warn_unresolved = true;
			break;
		case 'E':
			sec_mismatch_warn_only = false;
			break;
		case 'N':
			allow_missing_ns_imports = true;
			break;
		case 'd':
			missing_namespace_deps = optarg;
			break;
		default:
			exit(1);
		}
	}

	list_for_each_entry_safe(dl, dl2, &dump_lists, list) {
		read_dump(dl->file);
		list_del(&dl->list);
		free(dl);
	}

	while (optind < argc)
		read_symbols(argv[optind++]);

	if (files_source)
		read_symbols_from_files(files_source);

	list_for_each_entry(mod, &modules, list) {
		if (mod->from_dump || mod->is_vmlinux)
			continue;

		check_modname_len(mod);
		check_exports(mod);
	}

	if (unused_exports_white_list)
		handle_white_list_exports(unused_exports_white_list);

	list_for_each_entry(mod, &modules, list) {
		if (mod->from_dump)
			continue;

		if (mod->is_vmlinux)
			write_vmlinux_export_c_file(mod);
		else
			write_mod_c_file(mod);
	}

	if (missing_namespace_deps)
		write_namespace_deps_files(missing_namespace_deps);

	if (dump_write)
		write_dump(dump_write);
	if (sec_mismatch_count && !sec_mismatch_warn_only)
		error("Section mismatches detected.\n"
		      "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n");

	if (nr_unresolved > MAX_UNRESOLVED_REPORTS)
		warn("suppressed %u unresolved symbol warnings because there were too many)\n",
		     nr_unresolved - MAX_UNRESOLVED_REPORTS);

	return error_occurred ? 1 : 0;
}