aboutsummaryrefslogtreecommitdiffstats
path: root/kernel/bpf/btf.c
blob: 7d40da240891d3b0885ad97d1c43b0fa50611081 (plain) (blame)
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
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570
3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
3581
3582
3583
3584
3585
3586
3587
3588
3589
3590
3591
3592
3593
3594
3595
3596
3597
3598
3599
3600
3601
3602
3603
3604
3605
3606
3607
3608
3609
3610
3611
3612
3613
3614
3615
3616
3617
3618
3619
3620
3621
3622
3623
3624
3625
3626
3627
3628
3629
3630
3631
3632
3633
3634
3635
3636
3637
3638
3639
3640
3641
3642
3643
3644
3645
3646
3647
3648
3649
3650
3651
3652
3653
3654
3655
3656
3657
3658
3659
3660
3661
3662
3663
3664
3665
3666
3667
3668
3669
3670
3671
3672
3673
3674
3675
3676
3677
3678
3679
3680
3681
3682
3683
3684
3685
3686
3687
3688
3689
3690
3691
3692
3693
3694
3695
3696
3697
3698
3699
3700
3701
3702
3703
3704
3705
3706
3707
3708
3709
3710
3711
3712
3713
3714
3715
3716
3717
3718
3719
3720
3721
3722
3723
3724
3725
3726
3727
3728
3729
3730
3731
3732
3733
3734
3735
3736
3737
3738
3739
3740
3741
3742
3743
3744
3745
3746
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756
3757
3758
3759
3760
3761
3762
3763
3764
3765
3766
3767
3768
3769
3770
3771
3772
3773
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
3789
3790
3791
3792
3793
3794
3795
3796
3797
3798
3799
3800
3801
3802
3803
3804
3805
3806
3807
3808
3809
3810
3811
3812
3813
3814
3815
3816
3817
3818
3819
3820
3821
3822
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832
3833
3834
3835
3836
3837
3838
3839
3840
3841
3842
3843
3844
3845
3846
3847
3848
3849
3850
3851
3852
3853
3854
3855
3856
3857
3858
3859
3860
3861
3862
3863
3864
3865
3866
3867
3868
3869
3870
3871
3872
3873
3874
3875
3876
3877
3878
3879
3880
3881
3882
3883
3884
3885
3886
3887
3888
3889
3890
3891
3892
3893
3894
3895
3896
3897
3898
3899
3900
3901
3902
3903
3904
3905
3906
3907
3908
3909
3910
3911
3912
3913
3914
3915
3916
3917
3918
3919
3920
3921
3922
3923
3924
3925
3926
3927
3928
3929
3930
3931
3932
3933
3934
3935
3936
3937
3938
3939
3940
3941
3942
3943
3944
3945
3946
3947
3948
3949
3950
3951
3952
3953
3954
3955
3956
3957
3958
3959
3960
3961
3962
3963
3964
3965
3966
3967
3968
3969
3970
3971
3972
3973
3974
3975
3976
3977
3978
3979
3980
3981
3982
3983
3984
3985
3986
3987
3988
3989
3990
3991
3992
3993
3994
3995
3996
3997
3998
3999
4000
4001
4002
4003
4004
4005
4006
4007
4008
4009
4010
4011
4012
4013
4014
4015
4016
4017
4018
4019
4020
4021
4022
4023
4024
4025
4026
4027
4028
4029
4030
4031
4032
4033
4034
4035
4036
4037
4038
4039
4040
4041
4042
4043
4044
4045
4046
4047
4048
4049
4050
4051
4052
4053
4054
4055
4056
4057
4058
4059
4060
4061
4062
4063
4064
4065
4066
4067
4068
4069
4070
4071
4072
4073
4074
4075
4076
4077
4078
4079
4080
4081
4082
4083
4084
4085
4086
4087
4088
4089
4090
4091
4092
4093
4094
4095
4096
4097
4098
4099
4100
4101
4102
4103
4104
4105
4106
4107
4108
4109
4110
4111
4112
4113
4114
4115
4116
4117
4118
4119
4120
4121
4122
4123
4124
4125
4126
4127
4128
4129
4130
4131
4132
4133
4134
4135
4136
4137
4138
4139
4140
4141
4142
4143
4144
4145
4146
4147
4148
4149
4150
4151
4152
4153
4154
4155
4156
4157
4158
4159
4160
4161
4162
4163
4164
4165
4166
4167
4168
4169
4170
4171
4172
4173
4174
4175
4176
4177
4178
4179
4180
4181
4182
4183
4184
4185
4186
4187
4188
4189
4190
4191
4192
4193
4194
4195
4196
4197
4198
4199
4200
4201
4202
4203
4204
4205
4206
4207
4208
4209
4210
4211
4212
4213
4214
4215
4216
4217
4218
4219
4220
4221
4222
4223
4224
4225
4226
4227
4228
4229
4230
4231
4232
4233
4234
4235
4236
4237
4238
4239
4240
4241
4242
4243
4244
4245
4246
4247
4248
4249
4250
4251
4252
4253
4254
4255
4256
4257
4258
4259
4260
4261
4262
4263
4264
4265
4266
4267
4268
4269
4270
/* SPDX-License-Identifier: GPL-2.0 */
/* Copyright (c) 2018 Facebook */

#include <uapi/linux/btf.h>
#include <uapi/linux/bpf.h>
#include <uapi/linux/bpf_perf_event.h>
#include <uapi/linux/types.h>
#include <linux/seq_file.h>
#include <linux/compiler.h>
#include <linux/ctype.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/anon_inodes.h>
#include <linux/file.h>
#include <linux/uaccess.h>
#include <linux/kernel.h>
#include <linux/idr.h>
#include <linux/sort.h>
#include <linux/bpf_verifier.h>
#include <linux/btf.h>
#include <linux/skmsg.h>
#include <linux/perf_event.h>
#include <net/sock.h>

/* BTF (BPF Type Format) is the meta data format which describes
 * the data types of BPF program/map.  Hence, it basically focus
 * on the C programming language which the modern BPF is primary
 * using.
 *
 * ELF Section:
 * ~~~~~~~~~~~
 * The BTF data is stored under the ".BTF" ELF section
 *
 * struct btf_type:
 * ~~~~~~~~~~~~~~~
 * Each 'struct btf_type' object describes a C data type.
 * Depending on the type it is describing, a 'struct btf_type'
 * object may be followed by more data.  F.e.
 * To describe an array, 'struct btf_type' is followed by
 * 'struct btf_array'.
 *
 * 'struct btf_type' and any extra data following it are
 * 4 bytes aligned.
 *
 * Type section:
 * ~~~~~~~~~~~~~
 * The BTF type section contains a list of 'struct btf_type' objects.
 * Each one describes a C type.  Recall from the above section
 * that a 'struct btf_type' object could be immediately followed by extra
 * data in order to desribe some particular C types.
 *
 * type_id:
 * ~~~~~~~
 * Each btf_type object is identified by a type_id.  The type_id
 * is implicitly implied by the location of the btf_type object in
 * the BTF type section.  The first one has type_id 1.  The second
 * one has type_id 2...etc.  Hence, an earlier btf_type has
 * a smaller type_id.
 *
 * A btf_type object may refer to another btf_type object by using
 * type_id (i.e. the "type" in the "struct btf_type").
 *
 * NOTE that we cannot assume any reference-order.
 * A btf_type object can refer to an earlier btf_type object
 * but it can also refer to a later btf_type object.
 *
 * For example, to describe "const void *".  A btf_type
 * object describing "const" may refer to another btf_type
 * object describing "void *".  This type-reference is done
 * by specifying type_id:
 *
 * [1] CONST (anon) type_id=2
 * [2] PTR (anon) type_id=0
 *
 * The above is the btf_verifier debug log:
 *   - Each line started with "[?]" is a btf_type object
 *   - [?] is the type_id of the btf_type object.
 *   - CONST/PTR is the BTF_KIND_XXX
 *   - "(anon)" is the name of the type.  It just
 *     happens that CONST and PTR has no name.
 *   - type_id=XXX is the 'u32 type' in btf_type
 *
 * NOTE: "void" has type_id 0
 *
 * String section:
 * ~~~~~~~~~~~~~~
 * The BTF string section contains the names used by the type section.
 * Each string is referred by an "offset" from the beginning of the
 * string section.
 *
 * Each string is '\0' terminated.
 *
 * The first character in the string section must be '\0'
 * which is used to mean 'anonymous'. Some btf_type may not
 * have a name.
 */

/* BTF verification:
 *
 * To verify BTF data, two passes are needed.
 *
 * Pass #1
 * ~~~~~~~
 * The first pass is to collect all btf_type objects to
 * an array: "btf->types".
 *
 * Depending on the C type that a btf_type is describing,
 * a btf_type may be followed by extra data.  We don't know
 * how many btf_type is there, and more importantly we don't
 * know where each btf_type is located in the type section.
 *
 * Without knowing the location of each type_id, most verifications
 * cannot be done.  e.g. an earlier btf_type may refer to a later
 * btf_type (recall the "const void *" above), so we cannot
 * check this type-reference in the first pass.
 *
 * In the first pass, it still does some verifications (e.g.
 * checking the name is a valid offset to the string section).
 *
 * Pass #2
 * ~~~~~~~
 * The main focus is to resolve a btf_type that is referring
 * to another type.
 *
 * We have to ensure the referring type:
 * 1) does exist in the BTF (i.e. in btf->types[])
 * 2) does not cause a loop:
 *	struct A {
 *		struct B b;
 *	};
 *
 *	struct B {
 *		struct A a;
 *	};
 *
 * btf_type_needs_resolve() decides if a btf_type needs
 * to be resolved.
 *
 * The needs_resolve type implements the "resolve()" ops which
 * essentially does a DFS and detects backedge.
 *
 * During resolve (or DFS), different C types have different
 * "RESOLVED" conditions.
 *
 * When resolving a BTF_KIND_STRUCT, we need to resolve all its
 * members because a member is always referring to another
 * type.  A struct's member can be treated as "RESOLVED" if
 * it is referring to a BTF_KIND_PTR.  Otherwise, the
 * following valid C struct would be rejected:
 *
 *	struct A {
 *		int m;
 *		struct A *a;
 *	};
 *
 * When resolving a BTF_KIND_PTR, it needs to keep resolving if
 * it is referring to another BTF_KIND_PTR.  Otherwise, we cannot
 * detect a pointer loop, e.g.:
 * BTF_KIND_CONST -> BTF_KIND_PTR -> BTF_KIND_CONST -> BTF_KIND_PTR +
 *                        ^                                         |
 *                        +-----------------------------------------+
 *
 */

#define BITS_PER_U128 (sizeof(u64) * BITS_PER_BYTE * 2)
#define BITS_PER_BYTE_MASK (BITS_PER_BYTE - 1)
#define BITS_PER_BYTE_MASKED(bits) ((bits) & BITS_PER_BYTE_MASK)
#define BITS_ROUNDDOWN_BYTES(bits) ((bits) >> 3)
#define BITS_ROUNDUP_BYTES(bits) \
	(BITS_ROUNDDOWN_BYTES(bits) + !!BITS_PER_BYTE_MASKED(bits))

#define BTF_INFO_MASK 0x8f00ffff
#define BTF_INT_MASK 0x0fffffff
#define BTF_TYPE_ID_VALID(type_id) ((type_id) <= BTF_MAX_TYPE)
#define BTF_STR_OFFSET_VALID(name_off) ((name_off) <= BTF_MAX_NAME_OFFSET)

/* 16MB for 64k structs and each has 16 members and
 * a few MB spaces for the string section.
 * The hard limit is S32_MAX.
 */
#define BTF_MAX_SIZE (16 * 1024 * 1024)

#define for_each_member(i, struct_type, member)			\
	for (i = 0, member = btf_type_member(struct_type);	\
	     i < btf_type_vlen(struct_type);			\
	     i++, member++)

#define for_each_member_from(i, from, struct_type, member)		\
	for (i = from, member = btf_type_member(struct_type) + from;	\
	     i < btf_type_vlen(struct_type);				\
	     i++, member++)

#define for_each_vsi(i, struct_type, member)			\
	for (i = 0, member = btf_type_var_secinfo(struct_type);	\
	     i < btf_type_vlen(struct_type);			\
	     i++, member++)

#define for_each_vsi_from(i, from, struct_type, member)				\
	for (i = from, member = btf_type_var_secinfo(struct_type) + from;	\
	     i < btf_type_vlen(struct_type);					\
	     i++, member++)

DEFINE_IDR(btf_idr);
DEFINE_SPINLOCK(btf_idr_lock);

struct btf {
	void *data;
	struct btf_type **types;
	u32 *resolved_ids;
	u32 *resolved_sizes;
	const char *strings;
	void *nohdr_data;
	struct btf_header hdr;
	u32 nr_types;
	u32 types_size;
	u32 data_size;
	refcount_t refcnt;
	u32 id;
	struct rcu_head rcu;
};

enum verifier_phase {
	CHECK_META,
	CHECK_TYPE,
};

struct resolve_vertex {
	const struct btf_type *t;
	u32 type_id;
	u16 next_member;
};

enum visit_state {
	NOT_VISITED,
	VISITED,
	RESOLVED,
};

enum resolve_mode {
	RESOLVE_TBD,	/* To Be Determined */
	RESOLVE_PTR,	/* Resolving for Pointer */
	RESOLVE_STRUCT_OR_ARRAY,	/* Resolving for struct/union
					 * or array
					 */
};

#define MAX_RESOLVE_DEPTH 32

struct btf_sec_info {
	u32 off;
	u32 len;
};

struct btf_verifier_env {
	struct btf *btf;
	u8 *visit_states;
	struct resolve_vertex stack[MAX_RESOLVE_DEPTH];
	struct bpf_verifier_log log;
	u32 log_type_id;
	u32 top_stack;
	enum verifier_phase phase;
	enum resolve_mode resolve_mode;
};

static const char * const btf_kind_str[NR_BTF_KINDS] = {
	[BTF_KIND_UNKN]		= "UNKNOWN",
	[BTF_KIND_INT]		= "INT",
	[BTF_KIND_PTR]		= "PTR",
	[BTF_KIND_ARRAY]	= "ARRAY",
	[BTF_KIND_STRUCT]	= "STRUCT",
	[BTF_KIND_UNION]	= "UNION",
	[BTF_KIND_ENUM]		= "ENUM",
	[BTF_KIND_FWD]		= "FWD",
	[BTF_KIND_TYPEDEF]	= "TYPEDEF",
	[BTF_KIND_VOLATILE]	= "VOLATILE",
	[BTF_KIND_CONST]	= "CONST",
	[BTF_KIND_RESTRICT]	= "RESTRICT",
	[BTF_KIND_FUNC]		= "FUNC",
	[BTF_KIND_FUNC_PROTO]	= "FUNC_PROTO",
	[BTF_KIND_VAR]		= "VAR",
	[BTF_KIND_DATASEC]	= "DATASEC",
};

struct btf_kind_operations {
	s32 (*check_meta)(struct btf_verifier_env *env,
			  const struct btf_type *t,
			  u32 meta_left);
	int (*resolve)(struct btf_verifier_env *env,
		       const struct resolve_vertex *v);
	int (*check_member)(struct btf_verifier_env *env,
			    const struct btf_type *struct_type,
			    const struct btf_member *member,
			    const struct btf_type *member_type);
	int (*check_kflag_member)(struct btf_verifier_env *env,
				  const struct btf_type *struct_type,
				  const struct btf_member *member,
				  const struct btf_type *member_type);
	void (*log_details)(struct btf_verifier_env *env,
			    const struct btf_type *t);
	void (*seq_show)(const struct btf *btf, const struct btf_type *t,
			 u32 type_id, void *data, u8 bits_offsets,
			 struct seq_file *m);
};

static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS];
static struct btf_type btf_void;

static int btf_resolve(struct btf_verifier_env *env,
		       const struct btf_type *t, u32 type_id);

static bool btf_type_is_modifier(const struct btf_type *t)
{
	/* Some of them is not strictly a C modifier
	 * but they are grouped into the same bucket
	 * for BTF concern:
	 *   A type (t) that refers to another
	 *   type through t->type AND its size cannot
	 *   be determined without following the t->type.
	 *
	 * ptr does not fall into this bucket
	 * because its size is always sizeof(void *).
	 */
	switch (BTF_INFO_KIND(t->info)) {
	case BTF_KIND_TYPEDEF:
	case BTF_KIND_VOLATILE:
	case BTF_KIND_CONST:
	case BTF_KIND_RESTRICT:
		return true;
	}

	return false;
}

bool btf_type_is_void(const struct btf_type *t)
{
	return t == &btf_void;
}

static bool btf_type_is_fwd(const struct btf_type *t)
{
	return BTF_INFO_KIND(t->info) == BTF_KIND_FWD;
}

static bool btf_type_nosize(const struct btf_type *t)
{
	return btf_type_is_void(t) || btf_type_is_fwd(t) ||
	       btf_type_is_func(t) || btf_type_is_func_proto(t);
}

static bool btf_type_nosize_or_null(const struct btf_type *t)
{
	return !t || btf_type_nosize(t);
}

/* union is only a special case of struct:
 * all its offsetof(member) == 0
 */
static bool btf_type_is_struct(const struct btf_type *t)
{
	u8 kind = BTF_INFO_KIND(t->info);

	return kind == BTF_KIND_STRUCT || kind == BTF_KIND_UNION;
}

static bool __btf_type_is_struct(const struct btf_type *t)
{
	return BTF_INFO_KIND(t->info) == BTF_KIND_STRUCT;
}

static bool btf_type_is_array(const struct btf_type *t)
{
	return BTF_INFO_KIND(t->info) == BTF_KIND_ARRAY;
}

static bool btf_type_is_var(const struct btf_type *t)
{
	return BTF_INFO_KIND(t->info) == BTF_KIND_VAR;
}

static bool btf_type_is_datasec(const struct btf_type *t)
{
	return BTF_INFO_KIND(t->info) == BTF_KIND_DATASEC;
}

/* Types that act only as a source, not sink or intermediate
 * type when resolving.
 */
static bool btf_type_is_resolve_source_only(const struct btf_type *t)
{
	return btf_type_is_var(t) ||
	       btf_type_is_datasec(t);
}

/* What types need to be resolved?
 *
 * btf_type_is_modifier() is an obvious one.
 *
 * btf_type_is_struct() because its member refers to
 * another type (through member->type).
 *
 * btf_type_is_var() because the variable refers to
 * another type. btf_type_is_datasec() holds multiple
 * btf_type_is_var() types that need resolving.
 *
 * btf_type_is_array() because its element (array->type)
 * refers to another type.  Array can be thought of a
 * special case of struct while array just has the same
 * member-type repeated by array->nelems of times.
 */
static bool btf_type_needs_resolve(const struct btf_type *t)
{
	return btf_type_is_modifier(t) ||
	       btf_type_is_ptr(t) ||
	       btf_type_is_struct(t) ||
	       btf_type_is_array(t) ||
	       btf_type_is_var(t) ||
	       btf_type_is_datasec(t);
}

/* t->size can be used */
static bool btf_type_has_size(const struct btf_type *t)
{
	switch (BTF_INFO_KIND(t->info)) {
	case BTF_KIND_INT:
	case BTF_KIND_STRUCT:
	case BTF_KIND_UNION:
	case BTF_KIND_ENUM:
	case BTF_KIND_DATASEC:
		return true;
	}

	return false;
}

static const char *btf_int_encoding_str(u8 encoding)
{
	if (encoding == 0)
		return "(none)";
	else if (encoding == BTF_INT_SIGNED)
		return "SIGNED";
	else if (encoding == BTF_INT_CHAR)
		return "CHAR";
	else if (encoding == BTF_INT_BOOL)
		return "BOOL";
	else
		return "UNKN";
}

static u16 btf_type_vlen(const struct btf_type *t)
{
	return BTF_INFO_VLEN(t->info);
}

static bool btf_type_kflag(const struct btf_type *t)
{
	return BTF_INFO_KFLAG(t->info);
}

static u32 btf_member_bit_offset(const struct btf_type *struct_type,
			     const struct btf_member *member)
{
	return btf_type_kflag(struct_type) ? BTF_MEMBER_BIT_OFFSET(member->offset)
					   : member->offset;
}

static u32 btf_member_bitfield_size(const struct btf_type *struct_type,
				    const struct btf_member *member)
{
	return btf_type_kflag(struct_type) ? BTF_MEMBER_BITFIELD_SIZE(member->offset)
					   : 0;
}

static u32 btf_type_int(const struct btf_type *t)
{
	return *(u32 *)(t + 1);
}

static const struct btf_array *btf_type_array(const struct btf_type *t)
{
	return (const struct btf_array *)(t + 1);
}

static const struct btf_member *btf_type_member(const struct btf_type *t)
{
	return (const struct btf_member *)(t + 1);
}

static const struct btf_enum *btf_type_enum(const struct btf_type *t)
{
	return (const struct btf_enum *)(t + 1);
}

static const struct btf_var *btf_type_var(const struct btf_type *t)
{
	return (const struct btf_var *)(t + 1);
}

static const struct btf_var_secinfo *btf_type_var_secinfo(const struct btf_type *t)
{
	return (const struct btf_var_secinfo *)(t + 1);
}

static const struct btf_kind_operations *btf_type_ops(const struct btf_type *t)
{
	return kind_ops[BTF_INFO_KIND(t->info)];
}

static bool btf_name_offset_valid(const struct btf *btf, u32 offset)
{
	return BTF_STR_OFFSET_VALID(offset) &&
		offset < btf->hdr.str_len;
}

static bool __btf_name_char_ok(char c, bool first, bool dot_ok)
{
	if ((first ? !isalpha(c) :
		     !isalnum(c)) &&
	    c != '_' &&
	    ((c == '.' && !dot_ok) ||
	      c != '.'))
		return false;
	return true;
}

static bool __btf_name_valid(const struct btf *btf, u32 offset, bool dot_ok)
{
	/* offset must be valid */
	const char *src = &btf->strings[offset];
	const char *src_limit;

	if (!__btf_name_char_ok(*src, true, dot_ok))
		return false;

	/* set a limit on identifier length */
	src_limit = src + KSYM_NAME_LEN;
	src++;
	while (*src && src < src_limit) {
		if (!__btf_name_char_ok(*src, false, dot_ok))
			return false;
		src++;
	}

	return !*src;
}

/* Only C-style identifier is permitted. This can be relaxed if
 * necessary.
 */
static bool btf_name_valid_identifier(const struct btf *btf, u32 offset)
{
	return __btf_name_valid(btf, offset, false);
}

static bool btf_name_valid_section(const struct btf *btf, u32 offset)
{
	return __btf_name_valid(btf, offset, true);
}

static const char *__btf_name_by_offset(const struct btf *btf, u32 offset)
{
	if (!offset)
		return "(anon)";
	else if (offset < btf->hdr.str_len)
		return &btf->strings[offset];
	else
		return "(invalid-name-offset)";
}

const char *btf_name_by_offset(const struct btf *btf, u32 offset)
{
	if (offset < btf->hdr.str_len)
		return &btf->strings[offset];

	return NULL;
}

const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id)
{
	if (type_id > btf->nr_types)
		return NULL;

	return btf->types[type_id];
}

/*
 * Regular int is not a bit field and it must be either
 * u8/u16/u32/u64 or __int128.
 */
static bool btf_type_int_is_regular(const struct btf_type *t)
{
	u8 nr_bits, nr_bytes;
	u32 int_data;

	int_data = btf_type_int(t);
	nr_bits = BTF_INT_BITS(int_data);
	nr_bytes = BITS_ROUNDUP_BYTES(nr_bits);
	if (BITS_PER_BYTE_MASKED(nr_bits) ||
	    BTF_INT_OFFSET(int_data) ||
	    (nr_bytes != sizeof(u8) && nr_bytes != sizeof(u16) &&
	     nr_bytes != sizeof(u32) && nr_bytes != sizeof(u64) &&
	     nr_bytes != (2 * sizeof(u64)))) {
		return false;
	}

	return true;
}

/*
 * Check that given struct member is a regular int with expected
 * offset and size.
 */
bool btf_member_is_reg_int(const struct btf *btf, const struct btf_type *s,
			   const struct btf_member *m,
			   u32 expected_offset, u32 expected_size)
{
	const struct btf_type *t;
	u32 id, int_data;
	u8 nr_bits;

	id = m->type;
	t = btf_type_id_size(btf, &id, NULL);
	if (!t || !btf_type_is_int(t))
		return false;

	int_data = btf_type_int(t);
	nr_bits = BTF_INT_BITS(int_data);
	if (btf_type_kflag(s)) {
		u32 bitfield_size = BTF_MEMBER_BITFIELD_SIZE(m->offset);
		u32 bit_offset = BTF_MEMBER_BIT_OFFSET(m->offset);

		/* if kflag set, int should be a regular int and
		 * bit offset should be at byte boundary.
		 */
		return !bitfield_size &&
		       BITS_ROUNDUP_BYTES(bit_offset) == expected_offset &&
		       BITS_ROUNDUP_BYTES(nr_bits) == expected_size;
	}

	if (BTF_INT_OFFSET(int_data) ||
	    BITS_PER_BYTE_MASKED(m->offset) ||
	    BITS_ROUNDUP_BYTES(m->offset) != expected_offset ||
	    BITS_PER_BYTE_MASKED(nr_bits) ||
	    BITS_ROUNDUP_BYTES(nr_bits) != expected_size)
		return false;

	return true;
}

__printf(2, 3) static void __btf_verifier_log(struct bpf_verifier_log *log,
					      const char *fmt, ...)
{
	va_list args;

	va_start(args, fmt);
	bpf_verifier_vlog(log, fmt, args);
	va_end(args);
}

__printf(2, 3) static void btf_verifier_log(struct btf_verifier_env *env,
					    const char *fmt, ...)
{
	struct bpf_verifier_log *log = &env->log;
	va_list args;

	if (!bpf_verifier_log_needed(log))
		return;

	va_start(args, fmt);
	bpf_verifier_vlog(log, fmt, args);
	va_end(args);
}

__printf(4, 5) static void __btf_verifier_log_type(struct btf_verifier_env *env,
						   const struct btf_type *t,
						   bool log_details,
						   const char *fmt, ...)
{
	struct bpf_verifier_log *log = &env->log;
	u8 kind = BTF_INFO_KIND(t->info);
	struct btf *btf = env->btf;
	va_list args;

	if (!bpf_verifier_log_needed(log))
		return;

	/* btf verifier prints all types it is processing via
	 * btf_verifier_log_type(..., fmt = NULL).
	 * Skip those prints for in-kernel BTF verification.
	 */
	if (log->level == BPF_LOG_KERNEL && !fmt)
		return;

	__btf_verifier_log(log, "[%u] %s %s%s",
			   env->log_type_id,
			   btf_kind_str[kind],
			   __btf_name_by_offset(btf, t->name_off),
			   log_details ? " " : "");

	if (log_details)
		btf_type_ops(t)->log_details(env, t);

	if (fmt && *fmt) {
		__btf_verifier_log(log, " ");
		va_start(args, fmt);
		bpf_verifier_vlog(log, fmt, args);
		va_end(args);
	}

	__btf_verifier_log(log, "\n");
}

#define btf_verifier_log_type(env, t, ...) \
	__btf_verifier_log_type((env), (t), true, __VA_ARGS__)
#define btf_verifier_log_basic(env, t, ...) \
	__btf_verifier_log_type((env), (t), false, __VA_ARGS__)

__printf(4, 5)
static void btf_verifier_log_member(struct btf_verifier_env *env,
				    const struct btf_type *struct_type,
				    const struct btf_member *member,
				    const char *fmt, ...)
{
	struct bpf_verifier_log *log = &env->log;
	struct btf *btf = env->btf;
	va_list args;

	if (!bpf_verifier_log_needed(log))
		return;

	if (log->level == BPF_LOG_KERNEL && !fmt)
		return;
	/* The CHECK_META phase already did a btf dump.
	 *
	 * If member is logged again, it must hit an error in
	 * parsing this member.  It is useful to print out which
	 * struct this member belongs to.
	 */
	if (env->phase != CHECK_META)
		btf_verifier_log_type(env, struct_type, NULL);

	if (btf_type_kflag(struct_type))
		__btf_verifier_log(log,
				   "\t%s type_id=%u bitfield_size=%u bits_offset=%u",
				   __btf_name_by_offset(btf, member->name_off),
				   member->type,
				   BTF_MEMBER_BITFIELD_SIZE(member->offset),
				   BTF_MEMBER_BIT_OFFSET(member->offset));
	else
		__btf_verifier_log(log, "\t%s type_id=%u bits_offset=%u",
				   __btf_name_by_offset(btf, member->name_off),
				   member->type, member->offset);

	if (fmt && *fmt) {
		__btf_verifier_log(log, " ");
		va_start(args, fmt);
		bpf_verifier_vlog(log, fmt, args);
		va_end(args);
	}

	__btf_verifier_log(log, "\n");
}

__printf(4, 5)
static void btf_verifier_log_vsi(struct btf_verifier_env *env,
				 const struct btf_type *datasec_type,
				 const struct btf_var_secinfo *vsi,
				 const char *fmt, ...)
{
	struct bpf_verifier_log *log = &env->log;
	va_list args;

	if (!bpf_verifier_log_needed(log))
		return;
	if (log->level == BPF_LOG_KERNEL && !fmt)
		return;
	if (env->phase != CHECK_META)
		btf_verifier_log_type(env, datasec_type, NULL);

	__btf_verifier_log(log, "\t type_id=%u offset=%u size=%u",
			   vsi->type, vsi->offset, vsi->size);
	if (fmt && *fmt) {
		__btf_verifier_log(log, " ");
		va_start(args, fmt);
		bpf_verifier_vlog(log, fmt, args);
		va_end(args);
	}

	__btf_verifier_log(log, "\n");
}

static void btf_verifier_log_hdr(struct btf_verifier_env *env,
				 u32 btf_data_size)
{
	struct bpf_verifier_log *log = &env->log;
	const struct btf *btf = env->btf;
	const struct btf_header *hdr;

	if (!bpf_verifier_log_needed(log))
		return;

	if (log->level == BPF_LOG_KERNEL)
		return;
	hdr = &btf->hdr;
	__btf_verifier_log(log, "magic: 0x%x\n", hdr->magic);
	__btf_verifier_log(log, "version: %u\n", hdr->version);
	__btf_verifier_log(log, "flags: 0x%x\n", hdr->flags);
	__btf_verifier_log(log, "hdr_len: %u\n", hdr->hdr_len);
	__btf_verifier_log(log, "type_off: %u\n", hdr->type_off);
	__btf_verifier_log(log, "type_len: %u\n", hdr->type_len);
	__btf_verifier_log(log, "str_off: %u\n", hdr->str_off);
	__btf_verifier_log(log, "str_len: %u\n", hdr->str_len);
	__btf_verifier_log(log, "btf_total_size: %u\n", btf_data_size);
}

static int btf_add_type(struct btf_verifier_env *env, struct btf_type *t)
{
	struct btf *btf = env->btf;

	/* < 2 because +1 for btf_void which is always in btf->types[0].
	 * btf_void is not accounted in btf->nr_types because btf_void
	 * does not come from the BTF file.
	 */
	if (btf->types_size - btf->nr_types < 2) {
		/* Expand 'types' array */

		struct btf_type **new_types;
		u32 expand_by, new_size;

		if (btf->types_size == BTF_MAX_TYPE) {
			btf_verifier_log(env, "Exceeded max num of types");
			return -E2BIG;
		}

		expand_by = max_t(u32, btf->types_size >> 2, 16);
		new_size = min_t(u32, BTF_MAX_TYPE,
				 btf->types_size + expand_by);

		new_types = kvcalloc(new_size, sizeof(*new_types),
				     GFP_KERNEL | __GFP_NOWARN);
		if (!new_types)
			return -ENOMEM;

		if (btf->nr_types == 0)
			new_types[0] = &btf_void;
		else
			memcpy(new_types, btf->types,
			       sizeof(*btf->types) * (btf->nr_types + 1));

		kvfree(btf->types);
		btf->types = new_types;
		btf->types_size = new_size;
	}

	btf->types[++(btf->nr_types)] = t;

	return 0;
}

static int btf_alloc_id(struct btf *btf)
{
	int id;

	idr_preload(GFP_KERNEL);
	spin_lock_bh(&btf_idr_lock);
	id = idr_alloc_cyclic(&btf_idr, btf, 1, INT_MAX, GFP_ATOMIC);
	if (id > 0)
		btf->id = id;
	spin_unlock_bh(&btf_idr_lock);
	idr_preload_end();

	if (WARN_ON_ONCE(!id))
		return -ENOSPC;

	return id > 0 ? 0 : id;
}

static void btf_free_id(struct btf *btf)
{
	unsigned long flags;

	/*
	 * In map-in-map, calling map_delete_elem() on outer
	 * map will call bpf_map_put on the inner map.
	 * It will then eventually call btf_free_id()
	 * on the inner map.  Some of the map_delete_elem()
	 * implementation may have irq disabled, so
	 * we need to use the _irqsave() version instead
	 * of the _bh() version.
	 */
	spin_lock_irqsave(&btf_idr_lock, flags);
	idr_remove(&btf_idr, btf->id);
	spin_unlock_irqrestore(&btf_idr_lock, flags);
}

static void btf_free(struct btf *btf)
{
	kvfree(btf->types);
	kvfree(btf->resolved_sizes);
	kvfree(btf->resolved_ids);
	kvfree(btf->data);
	kfree(btf);
}

static void btf_free_rcu(struct rcu_head *rcu)
{
	struct btf *btf = container_of(rcu, struct btf, rcu);

	btf_free(btf);
}

void btf_put(struct btf *btf)
{
	if (btf && refcount_dec_and_test(&btf->refcnt)) {
		btf_free_id(btf);
		call_rcu(&btf->rcu, btf_free_rcu);
	}
}

static int env_resolve_init(struct btf_verifier_env *env)
{
	struct btf *btf = env->btf;
	u32 nr_types = btf->nr_types;
	u32 *resolved_sizes = NULL;
	u32 *resolved_ids = NULL;
	u8 *visit_states = NULL;

	/* +1 for btf_void */
	resolved_sizes = kvcalloc(nr_types + 1, sizeof(*resolved_sizes),
				  GFP_KERNEL | __GFP_NOWARN);
	if (!resolved_sizes)
		goto nomem;

	resolved_ids = kvcalloc(nr_types + 1, sizeof(*resolved_ids),
				GFP_KERNEL | __GFP_NOWARN);
	if (!resolved_ids)
		goto nomem;

	visit_states = kvcalloc(nr_types + 1, sizeof(*visit_states),
				GFP_KERNEL | __GFP_NOWARN);
	if (!visit_states)
		goto nomem;

	btf->resolved_sizes = resolved_sizes;
	btf->resolved_ids = resolved_ids;
	env->visit_states = visit_states;

	return 0;

nomem:
	kvfree(resolved_sizes);
	kvfree(resolved_ids);
	kvfree(visit_states);
	return -ENOMEM;
}

static void btf_verifier_env_free(struct btf_verifier_env *env)
{
	kvfree(env->visit_states);
	kfree(env);
}

static bool env_type_is_resolve_sink(const struct btf_verifier_env *env,
				     const struct btf_type *next_type)
{
	switch (env->resolve_mode) {
	case RESOLVE_TBD:
		/* int, enum or void is a sink */
		return !btf_type_needs_resolve(next_type);
	case RESOLVE_PTR:
		/* int, enum, void, struct, array, func or func_proto is a sink
		 * for ptr
		 */
		return !btf_type_is_modifier(next_type) &&
			!btf_type_is_ptr(next_type);
	case RESOLVE_STRUCT_OR_ARRAY:
		/* int, enum, void, ptr, func or func_proto is a sink
		 * for struct and array
		 */
		return !btf_type_is_modifier(next_type) &&
			!btf_type_is_array(next_type) &&
			!btf_type_is_struct(next_type);
	default:
		BUG();
	}
}

static bool env_type_is_resolved(const struct btf_verifier_env *env,
				 u32 type_id)
{
	return env->visit_states[type_id] == RESOLVED;
}

static int env_stack_push(struct btf_verifier_env *env,
			  const struct btf_type *t, u32 type_id)
{
	struct resolve_vertex *v;

	if (env->top_stack == MAX_RESOLVE_DEPTH)
		return -E2BIG;

	if (env->visit_states[type_id] != NOT_VISITED)
		return -EEXIST;

	env->visit_states[type_id] = VISITED;

	v = &env->stack[env->top_stack++];
	v->t = t;
	v->type_id = type_id;
	v->next_member = 0;

	if (env->resolve_mode == RESOLVE_TBD) {
		if (btf_type_is_ptr(t))
			env->resolve_mode = RESOLVE_PTR;
		else if (btf_type_is_struct(t) || btf_type_is_array(t))
			env->resolve_mode = RESOLVE_STRUCT_OR_ARRAY;
	}

	return 0;
}

static void env_stack_set_next_member(struct btf_verifier_env *env,
				      u16 next_member)
{
	env->stack[env->top_stack - 1].next_member = next_member;
}

static void env_stack_pop_resolved(struct btf_verifier_env *env,
				   u32 resolved_type_id,
				   u32 resolved_size)
{
	u32 type_id = env->stack[--(env->top_stack)].type_id;
	struct btf *btf = env->btf;

	btf->resolved_sizes[type_id] = resolved_size;
	btf->resolved_ids[type_id] = resolved_type_id;
	env->visit_states[type_id] = RESOLVED;
}

static const struct resolve_vertex *env_stack_peak(struct btf_verifier_env *env)
{
	return env->top_stack ? &env->stack[env->top_stack - 1] : NULL;
}

/* Resolve the size of a passed-in "type"
 *
 * type: is an array (e.g. u32 array[x][y])
 * return type: type "u32[x][y]", i.e. BTF_KIND_ARRAY,
 * *type_size: (x * y * sizeof(u32)).  Hence, *type_size always
 *             corresponds to the return type.
 * *elem_type: u32
 * *total_nelems: (x * y).  Hence, individual elem size is
 *                (*type_size / *total_nelems)
 *
 * type: is not an array (e.g. const struct X)
 * return type: type "struct X"
 * *type_size: sizeof(struct X)
 * *elem_type: same as return type ("struct X")
 * *total_nelems: 1
 */
static const struct btf_type *
btf_resolve_size(const struct btf *btf, const struct btf_type *type,
		 u32 *type_size, const struct btf_type **elem_type,
		 u32 *total_nelems)
{
	const struct btf_type *array_type = NULL;
	const struct btf_array *array;
	u32 i, size, nelems = 1;

	for (i = 0; i < MAX_RESOLVE_DEPTH; i++) {
		switch (BTF_INFO_KIND(type->info)) {
		/* type->size can be used */
		case BTF_KIND_INT:
		case BTF_KIND_STRUCT:
		case BTF_KIND_UNION:
		case BTF_KIND_ENUM:
			size = type->size;
			goto resolved;

		case BTF_KIND_PTR:
			size = sizeof(void *);
			goto resolved;

		/* Modifiers */
		case BTF_KIND_TYPEDEF:
		case BTF_KIND_VOLATILE:
		case BTF_KIND_CONST:
		case BTF_KIND_RESTRICT:
			type = btf_type_by_id(btf, type->type);
			break;

		case BTF_KIND_ARRAY:
			if (!array_type)
				array_type = type;
			array = btf_type_array(type);
			if (nelems && array->nelems > U32_MAX / nelems)
				return ERR_PTR(-EINVAL);
			nelems *= array->nelems;
			type = btf_type_by_id(btf, array->type);
			break;

		/* type without size */
		default:
			return ERR_PTR(-EINVAL);
		}
	}

	return ERR_PTR(-EINVAL);

resolved:
	if (nelems && size > U32_MAX / nelems)
		return ERR_PTR(-EINVAL);

	*type_size = nelems * size;
	*total_nelems = nelems;
	*elem_type = type;

	return array_type ? : type;
}

/* The input param "type_id" must point to a needs_resolve type */
static const struct btf_type *btf_type_id_resolve(const struct btf *btf,
						  u32 *type_id)
{
	*type_id = btf->resolved_ids[*type_id];
	return btf_type_by_id(btf, *type_id);
}

const struct btf_type *btf_type_id_size(const struct btf *btf,
					u32 *type_id, u32 *ret_size)
{
	const struct btf_type *size_type;
	u32 size_type_id = *type_id;
	u32 size = 0;

	size_type = btf_type_by_id(btf, size_type_id);
	if (btf_type_nosize_or_null(size_type))
		return NULL;

	if (btf_type_has_size(size_type)) {
		size = size_type->size;
	} else if (btf_type_is_array(size_type)) {
		size = btf->resolved_sizes[size_type_id];
	} else if (btf_type_is_ptr(size_type)) {
		size = sizeof(void *);
	} else {
		if (WARN_ON_ONCE(!btf_type_is_modifier(size_type) &&
				 !btf_type_is_var(size_type)))
			return NULL;

		size_type_id = btf->resolved_ids[size_type_id];
		size_type = btf_type_by_id(btf, size_type_id);
		if (btf_type_nosize_or_null(size_type))
			return NULL;
		else if (btf_type_has_size(size_type))
			size = size_type->size;
		else if (btf_type_is_array(size_type))
			size = btf->resolved_sizes[size_type_id];
		else if (btf_type_is_ptr(size_type))
			size = sizeof(void *);
		else
			return NULL;
	}

	*type_id = size_type_id;
	if (ret_size)
		*ret_size = size;

	return size_type;
}

static int btf_df_check_member(struct btf_verifier_env *env,
			       const struct btf_type *struct_type,
			       const struct btf_member *member,
			       const struct btf_type *member_type)
{
	btf_verifier_log_basic(env, struct_type,
			       "Unsupported check_member");
	return -EINVAL;
}

static int btf_df_check_kflag_member(struct btf_verifier_env *env,
				     const struct btf_type *struct_type,
				     const struct btf_member *member,
				     const struct btf_type *member_type)
{
	btf_verifier_log_basic(env, struct_type,
			       "Unsupported check_kflag_member");
	return -EINVAL;
}

/* Used for ptr, array and struct/union type members.
 * int, enum and modifier types have their specific callback functions.
 */
static int btf_generic_check_kflag_member(struct btf_verifier_env *env,
					  const struct btf_type *struct_type,
					  const struct btf_member *member,
					  const struct btf_type *member_type)
{
	if (BTF_MEMBER_BITFIELD_SIZE(member->offset)) {
		btf_verifier_log_member(env, struct_type, member,
					"Invalid member bitfield_size");
		return -EINVAL;
	}

	/* bitfield size is 0, so member->offset represents bit offset only.
	 * It is safe to call non kflag check_member variants.
	 */
	return btf_type_ops(member_type)->check_member(env, struct_type,
						       member,
						       member_type);
}

static int btf_df_resolve(struct btf_verifier_env *env,
			  const struct resolve_vertex *v)
{
	btf_verifier_log_basic(env, v->t, "Unsupported resolve");
	return -EINVAL;
}

static void btf_df_seq_show(const struct btf *btf, const struct btf_type *t,
			    u32 type_id, void *data, u8 bits_offsets,
			    struct seq_file *m)
{
	seq_printf(m, "<unsupported kind:%u>", BTF_INFO_KIND(t->info));
}

static int btf_int_check_member(struct btf_verifier_env *env,
				const struct btf_type *struct_type,
				const struct btf_member *member,
				const struct btf_type *member_type)
{
	u32 int_data = btf_type_int(member_type);
	u32 struct_bits_off = member->offset;
	u32 struct_size = struct_type->size;
	u32 nr_copy_bits;
	u32 bytes_offset;

	if (U32_MAX - struct_bits_off < BTF_INT_OFFSET(int_data)) {
		btf_verifier_log_member(env, struct_type, member,
					"bits_offset exceeds U32_MAX");
		return -EINVAL;
	}

	struct_bits_off += BTF_INT_OFFSET(int_data);
	bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
	nr_copy_bits = BTF_INT_BITS(int_data) +
		BITS_PER_BYTE_MASKED(struct_bits_off);

	if (nr_copy_bits > BITS_PER_U128) {
		btf_verifier_log_member(env, struct_type, member,
					"nr_copy_bits exceeds 128");
		return -EINVAL;
	}

	if (struct_size < bytes_offset ||
	    struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) {
		btf_verifier_log_member(env, struct_type, member,
					"Member exceeds struct_size");
		return -EINVAL;
	}

	return 0;
}

static int btf_int_check_kflag_member(struct btf_verifier_env *env,
				      const struct btf_type *struct_type,
				      const struct btf_member *member,
				      const struct btf_type *member_type)
{
	u32 struct_bits_off, nr_bits, nr_int_data_bits, bytes_offset;
	u32 int_data = btf_type_int(member_type);
	u32 struct_size = struct_type->size;
	u32 nr_copy_bits;

	/* a regular int type is required for the kflag int member */
	if (!btf_type_int_is_regular(member_type)) {
		btf_verifier_log_member(env, struct_type, member,
					"Invalid member base type");
		return -EINVAL;
	}

	/* check sanity of bitfield size */
	nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset);
	struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset);
	nr_int_data_bits = BTF_INT_BITS(int_data);
	if (!nr_bits) {
		/* Not a bitfield member, member offset must be at byte
		 * boundary.
		 */
		if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
			btf_verifier_log_member(env, struct_type, member,
						"Invalid member offset");
			return -EINVAL;
		}

		nr_bits = nr_int_data_bits;
	} else if (nr_bits > nr_int_data_bits) {
		btf_verifier_log_member(env, struct_type, member,
					"Invalid member bitfield_size");
		return -EINVAL;
	}

	bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
	nr_copy_bits = nr_bits + BITS_PER_BYTE_MASKED(struct_bits_off);
	if (nr_copy_bits > BITS_PER_U128) {
		btf_verifier_log_member(env, struct_type, member,
					"nr_copy_bits exceeds 128");
		return -EINVAL;
	}

	if (struct_size < bytes_offset ||
	    struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) {
		btf_verifier_log_member(env, struct_type, member,
					"Member exceeds struct_size");
		return -EINVAL;
	}

	return 0;
}

static s32 btf_int_check_meta(struct btf_verifier_env *env,
			      const struct btf_type *t,
			      u32 meta_left)
{
	u32 int_data, nr_bits, meta_needed = sizeof(int_data);
	u16 encoding;

	if (meta_left < meta_needed) {
		btf_verifier_log_basic(env, t,
				       "meta_left:%u meta_needed:%u",
				       meta_left, meta_needed);
		return -EINVAL;
	}

	if (btf_type_vlen(t)) {
		btf_verifier_log_type(env, t, "vlen != 0");
		return -EINVAL;
	}

	if (btf_type_kflag(t)) {
		btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
		return -EINVAL;
	}

	int_data = btf_type_int(t);
	if (int_data & ~BTF_INT_MASK) {
		btf_verifier_log_basic(env, t, "Invalid int_data:%x",
				       int_data);
		return -EINVAL;
	}

	nr_bits = BTF_INT_BITS(int_data) + BTF_INT_OFFSET(int_data);

	if (nr_bits > BITS_PER_U128) {
		btf_verifier_log_type(env, t, "nr_bits exceeds %zu",
				      BITS_PER_U128);
		return -EINVAL;
	}

	if (BITS_ROUNDUP_BYTES(nr_bits) > t->size) {
		btf_verifier_log_type(env, t, "nr_bits exceeds type_size");
		return -EINVAL;
	}

	/*
	 * Only one of the encoding bits is allowed and it
	 * should be sufficient for the pretty print purpose (i.e. decoding).
	 * Multiple bits can be allowed later if it is found
	 * to be insufficient.
	 */
	encoding = BTF_INT_ENCODING(int_data);
	if (encoding &&
	    encoding != BTF_INT_SIGNED &&
	    encoding != BTF_INT_CHAR &&
	    encoding != BTF_INT_BOOL) {
		btf_verifier_log_type(env, t, "Unsupported encoding");
		return -ENOTSUPP;
	}

	btf_verifier_log_type(env, t, NULL);

	return meta_needed;
}

static void btf_int_log(struct btf_verifier_env *env,
			const struct btf_type *t)
{
	int int_data = btf_type_int(t);

	btf_verifier_log(env,
			 "size=%u bits_offset=%u nr_bits=%u encoding=%s",
			 t->size, BTF_INT_OFFSET(int_data),
			 BTF_INT_BITS(int_data),
			 btf_int_encoding_str(BTF_INT_ENCODING(int_data)));
}

static void btf_int128_print(struct seq_file *m, void *data)
{
	/* data points to a __int128 number.
	 * Suppose
	 *     int128_num = *(__int128 *)data;
	 * The below formulas shows what upper_num and lower_num represents:
	 *     upper_num = int128_num >> 64;
	 *     lower_num = int128_num & 0xffffffffFFFFFFFFULL;
	 */
	u64 upper_num, lower_num;

#ifdef __BIG_ENDIAN_BITFIELD
	upper_num = *(u64 *)data;
	lower_num = *(u64 *)(data + 8);
#else
	upper_num = *(u64 *)(data + 8);
	lower_num = *(u64 *)data;
#endif
	if (upper_num == 0)
		seq_printf(m, "0x%llx", lower_num);
	else
		seq_printf(m, "0x%llx%016llx", upper_num, lower_num);
}

static void btf_int128_shift(u64 *print_num, u16 left_shift_bits,
			     u16 right_shift_bits)
{
	u64 upper_num, lower_num;

#ifdef __BIG_ENDIAN_BITFIELD
	upper_num = print_num[0];
	lower_num = print_num[1];
#else
	upper_num = print_num[1];
	lower_num = print_num[0];
#endif

	/* shake out un-needed bits by shift/or operations */
	if (left_shift_bits >= 64) {
		upper_num = lower_num << (left_shift_bits - 64);
		lower_num = 0;
	} else {
		upper_num = (upper_num << left_shift_bits) |
			    (lower_num >> (64 - left_shift_bits));
		lower_num = lower_num << left_shift_bits;
	}

	if (right_shift_bits >= 64) {
		lower_num = upper_num >> (right_shift_bits - 64);
		upper_num = 0;
	} else {
		lower_num = (lower_num >> right_shift_bits) |
			    (upper_num << (64 - right_shift_bits));
		upper_num = upper_num >> right_shift_bits;
	}

#ifdef __BIG_ENDIAN_BITFIELD
	print_num[0] = upper_num;
	print_num[1] = lower_num;
#else
	print_num[0] = lower_num;
	print_num[1] = upper_num;
#endif
}

static void btf_bitfield_seq_show(void *data, u8 bits_offset,
				  u8 nr_bits, struct seq_file *m)
{
	u16 left_shift_bits, right_shift_bits;
	u8 nr_copy_bytes;
	u8 nr_copy_bits;
	u64 print_num[2] = {};

	nr_copy_bits = nr_bits + bits_offset;
	nr_copy_bytes = BITS_ROUNDUP_BYTES(nr_copy_bits);

	memcpy(print_num, data, nr_copy_bytes);

#ifdef __BIG_ENDIAN_BITFIELD
	left_shift_bits = bits_offset;
#else
	left_shift_bits = BITS_PER_U128 - nr_copy_bits;
#endif
	right_shift_bits = BITS_PER_U128 - nr_bits;

	btf_int128_shift(print_num, left_shift_bits, right_shift_bits);
	btf_int128_print(m, print_num);
}


static void btf_int_bits_seq_show(const struct btf *btf,
				  const struct btf_type *t,
				  void *data, u8 bits_offset,
				  struct seq_file *m)
{
	u32 int_data = btf_type_int(t);
	u8 nr_bits = BTF_INT_BITS(int_data);
	u8 total_bits_offset;

	/*
	 * bits_offset is at most 7.
	 * BTF_INT_OFFSET() cannot exceed 128 bits.
	 */
	total_bits_offset = bits_offset + BTF_INT_OFFSET(int_data);
	data += BITS_ROUNDDOWN_BYTES(total_bits_offset);
	bits_offset = BITS_PER_BYTE_MASKED(total_bits_offset);
	btf_bitfield_seq_show(data, bits_offset, nr_bits, m);
}

static void btf_int_seq_show(const struct btf *btf, const struct btf_type *t,
			     u32 type_id, void *data, u8 bits_offset,
			     struct seq_file *m)
{
	u32 int_data = btf_type_int(t);
	u8 encoding = BTF_INT_ENCODING(int_data);
	bool sign = encoding & BTF_INT_SIGNED;
	u8 nr_bits = BTF_INT_BITS(int_data);

	if (bits_offset || BTF_INT_OFFSET(int_data) ||
	    BITS_PER_BYTE_MASKED(nr_bits)) {
		btf_int_bits_seq_show(btf, t, data, bits_offset, m);
		return;
	}

	switch (nr_bits) {
	case 128:
		btf_int128_print(m, data);
		break;
	case 64:
		if (sign)
			seq_printf(m, "%lld", *(s64 *)data);
		else
			seq_printf(m, "%llu", *(u64 *)data);
		break;
	case 32:
		if (sign)
			seq_printf(m, "%d", *(s32 *)data);
		else
			seq_printf(m, "%u", *(u32 *)data);
		break;
	case 16:
		if (sign)
			seq_printf(m, "%d", *(s16 *)data);
		else
			seq_printf(m, "%u", *(u16 *)data);
		break;
	case 8:
		if (sign)
			seq_printf(m, "%d", *(s8 *)data);
		else
			seq_printf(m, "%u", *(u8 *)data);
		break;
	default:
		btf_int_bits_seq_show(btf, t, data, bits_offset, m);
	}
}

static const struct btf_kind_operations int_ops = {
	.check_meta = btf_int_check_meta,
	.resolve = btf_df_resolve,
	.check_member = btf_int_check_member,
	.check_kflag_member = btf_int_check_kflag_member,
	.log_details = btf_int_log,
	.seq_show = btf_int_seq_show,
};

static int btf_modifier_check_member(struct btf_verifier_env *env,
				     const struct btf_type *struct_type,
				     const struct btf_member *member,
				     const struct btf_type *member_type)
{
	const struct btf_type *resolved_type;
	u32 resolved_type_id = member->type;
	struct btf_member resolved_member;
	struct btf *btf = env->btf;

	resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL);
	if (!resolved_type) {
		btf_verifier_log_member(env, struct_type, member,
					"Invalid member");
		return -EINVAL;
	}

	resolved_member = *member;
	resolved_member.type = resolved_type_id;

	return btf_type_ops(resolved_type)->check_member(env, struct_type,
							 &resolved_member,
							 resolved_type);
}

static int btf_modifier_check_kflag_member(struct btf_verifier_env *env,
					   const struct btf_type *struct_type,
					   const struct btf_member *member,
					   const struct btf_type *member_type)
{
	const struct btf_type *resolved_type;
	u32 resolved_type_id = member->type;
	struct btf_member resolved_member;
	struct btf *btf = env->btf;

	resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL);
	if (!resolved_type) {
		btf_verifier_log_member(env, struct_type, member,
					"Invalid member");
		return -EINVAL;
	}

	resolved_member = *member;
	resolved_member.type = resolved_type_id;

	return btf_type_ops(resolved_type)->check_kflag_member(env, struct_type,
							       &resolved_member,
							       resolved_type);
}

static int btf_ptr_check_member(struct btf_verifier_env *env,
				const struct btf_type *struct_type,
				const struct btf_member *member,
				const struct btf_type *member_type)
{
	u32 struct_size, struct_bits_off, bytes_offset;

	struct_size = struct_type->size;
	struct_bits_off = member->offset;
	bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);

	if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
		btf_verifier_log_member(env, struct_type, member,
					"Member is not byte aligned");
		return -EINVAL;
	}

	if (struct_size - bytes_offset < sizeof(void *)) {
		btf_verifier_log_member(env, struct_type, member,
					"Member exceeds struct_size");
		return -EINVAL;
	}

	return 0;
}

static int btf_ref_type_check_meta(struct btf_verifier_env *env,
				   const struct btf_type *t,
				   u32 meta_left)
{
	if (btf_type_vlen(t)) {
		btf_verifier_log_type(env, t, "vlen != 0");
		return -EINVAL;
	}

	if (btf_type_kflag(t)) {
		btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
		return -EINVAL;
	}

	if (!BTF_TYPE_ID_VALID(t->type)) {
		btf_verifier_log_type(env, t, "Invalid type_id");
		return -EINVAL;
	}

	/* typedef type must have a valid name, and other ref types,
	 * volatile, const, restrict, should have a null name.
	 */
	if (BTF_INFO_KIND(t->info) == BTF_KIND_TYPEDEF) {
		if (!t->name_off ||
		    !btf_name_valid_identifier(env->btf, t->name_off)) {
			btf_verifier_log_type(env, t, "Invalid name");
			return -EINVAL;
		}
	} else {
		if (t->name_off) {
			btf_verifier_log_type(env, t, "Invalid name");
			return -EINVAL;
		}
	}

	btf_verifier_log_type(env, t, NULL);

	return 0;
}

static int btf_modifier_resolve(struct btf_verifier_env *env,
				const struct resolve_vertex *v)
{
	const struct btf_type *t = v->t;
	const struct btf_type *next_type;
	u32 next_type_id = t->type;
	struct btf *btf = env->btf;

	next_type = btf_type_by_id(btf, next_type_id);
	if (!next_type || btf_type_is_resolve_source_only(next_type)) {
		btf_verifier_log_type(env, v->t, "Invalid type_id");
		return -EINVAL;
	}

	if (!env_type_is_resolve_sink(env, next_type) &&
	    !env_type_is_resolved(env, next_type_id))
		return env_stack_push(env, next_type, next_type_id);

	/* Figure out the resolved next_type_id with size.
	 * They will be stored in the current modifier's
	 * resolved_ids and resolved_sizes such that it can
	 * save us a few type-following when we use it later (e.g. in
	 * pretty print).
	 */
	if (!btf_type_id_size(btf, &next_type_id, NULL)) {
		if (env_type_is_resolved(env, next_type_id))
			next_type = btf_type_id_resolve(btf, &next_type_id);

		/* "typedef void new_void", "const void"...etc */
		if (!btf_type_is_void(next_type) &&
		    !btf_type_is_fwd(next_type) &&
		    !btf_type_is_func_proto(next_type)) {
			btf_verifier_log_type(env, v->t, "Invalid type_id");
			return -EINVAL;
		}
	}

	env_stack_pop_resolved(env, next_type_id, 0);

	return 0;
}

static int btf_var_resolve(struct btf_verifier_env *env,
			   const struct resolve_vertex *v)
{
	const struct btf_type *next_type;
	const struct btf_type *t = v->t;
	u32 next_type_id = t->type;
	struct btf *btf = env->btf;

	next_type = btf_type_by_id(btf, next_type_id);
	if (!next_type || btf_type_is_resolve_source_only(next_type)) {
		btf_verifier_log_type(env, v->t, "Invalid type_id");
		return -EINVAL;
	}

	if (!env_type_is_resolve_sink(env, next_type) &&
	    !env_type_is_resolved(env, next_type_id))
		return env_stack_push(env, next_type, next_type_id);

	if (btf_type_is_modifier(next_type)) {
		const struct btf_type *resolved_type;
		u32 resolved_type_id;

		resolved_type_id = next_type_id;
		resolved_type = btf_type_id_resolve(btf, &resolved_type_id);

		if (btf_type_is_ptr(resolved_type) &&
		    !env_type_is_resolve_sink(env, resolved_type) &&
		    !env_type_is_resolved(env, resolved_type_id))
			return env_stack_push(env, resolved_type,
					      resolved_type_id);
	}

	/* We must resolve to something concrete at this point, no
	 * forward types or similar that would resolve to size of
	 * zero is allowed.
	 */
	if (!btf_type_id_size(btf, &next_type_id, NULL)) {
		btf_verifier_log_type(env, v->t, "Invalid type_id");
		return -EINVAL;
	}

	env_stack_pop_resolved(env, next_type_id, 0);

	return 0;
}

static int btf_ptr_resolve(struct btf_verifier_env *env,
			   const struct resolve_vertex *v)
{
	const struct btf_type *next_type;
	const struct btf_type *t = v->t;
	u32 next_type_id = t->type;
	struct btf *btf = env->btf;

	next_type = btf_type_by_id(btf, next_type_id);
	if (!next_type || btf_type_is_resolve_source_only(next_type)) {
		btf_verifier_log_type(env, v->t, "Invalid type_id");
		return -EINVAL;
	}

	if (!env_type_is_resolve_sink(env, next_type) &&
	    !env_type_is_resolved(env, next_type_id))
		return env_stack_push(env, next_type, next_type_id);

	/* If the modifier was RESOLVED during RESOLVE_STRUCT_OR_ARRAY,
	 * the modifier may have stopped resolving when it was resolved
	 * to a ptr (last-resolved-ptr).
	 *
	 * We now need to continue from the last-resolved-ptr to
	 * ensure the last-resolved-ptr will not referring back to
	 * the currenct ptr (t).
	 */
	if (btf_type_is_modifier(next_type)) {
		const struct btf_type *resolved_type;
		u32 resolved_type_id;

		resolved_type_id = next_type_id;
		resolved_type = btf_type_id_resolve(btf, &resolved_type_id);

		if (btf_type_is_ptr(resolved_type) &&
		    !env_type_is_resolve_sink(env, resolved_type) &&
		    !env_type_is_resolved(env, resolved_type_id))
			return env_stack_push(env, resolved_type,
					      resolved_type_id);
	}

	if (!btf_type_id_size(btf, &next_type_id, NULL)) {
		if (env_type_is_resolved(env, next_type_id))
			next_type = btf_type_id_resolve(btf, &next_type_id);

		if (!btf_type_is_void(next_type) &&
		    !btf_type_is_fwd(next_type) &&
		    !btf_type_is_func_proto(next_type)) {
			btf_verifier_log_type(env, v->t, "Invalid type_id");
			return -EINVAL;
		}
	}

	env_stack_pop_resolved(env, next_type_id, 0);

	return 0;
}

static void btf_modifier_seq_show(const struct btf *btf,
				  const struct btf_type *t,
				  u32 type_id, void *data,
				  u8 bits_offset, struct seq_file *m)
{
	t = btf_type_id_resolve(btf, &type_id);

	btf_type_ops(t)->seq_show(btf, t, type_id, data, bits_offset, m);
}

static void btf_var_seq_show(const struct btf *btf, const struct btf_type *t,
			     u32 type_id, void *data, u8 bits_offset,
			     struct seq_file *m)
{
	t = btf_type_id_resolve(btf, &type_id);

	btf_type_ops(t)->seq_show(btf, t, type_id, data, bits_offset, m);
}

static void btf_ptr_seq_show(const struct btf *btf, const struct btf_type *t,
			     u32 type_id, void *data, u8 bits_offset,
			     struct seq_file *m)
{
	/* It is a hashed value */
	seq_printf(m, "%p", *(void **)data);
}

static void btf_ref_type_log(struct btf_verifier_env *env,
			     const struct btf_type *t)
{
	btf_verifier_log(env, "type_id=%u", t->type);
}

static struct btf_kind_operations modifier_ops = {
	.check_meta = btf_ref_type_check_meta,
	.resolve = btf_modifier_resolve,
	.check_member = btf_modifier_check_member,
	.check_kflag_member = btf_modifier_check_kflag_member,
	.log_details = btf_ref_type_log,
	.seq_show = btf_modifier_seq_show,
};

static struct btf_kind_operations ptr_ops = {
	.check_meta = btf_ref_type_check_meta,
	.resolve = btf_ptr_resolve,
	.check_member = btf_ptr_check_member,
	.check_kflag_member = btf_generic_check_kflag_member,
	.log_details = btf_ref_type_log,
	.seq_show = btf_ptr_seq_show,
};

static s32 btf_fwd_check_meta(struct btf_verifier_env *env,
			      const struct btf_type *t,
			      u32 meta_left)
{
	if (btf_type_vlen(t)) {
		btf_verifier_log_type(env, t, "vlen != 0");
		return -EINVAL;
	}

	if (t->type) {
		btf_verifier_log_type(env, t, "type != 0");
		return -EINVAL;
	}

	/* fwd type must have a valid name */
	if (!t->name_off ||
	    !btf_name_valid_identifier(env->btf, t->name_off)) {
		btf_verifier_log_type(env, t, "Invalid name");
		return -EINVAL;
	}

	btf_verifier_log_type(env, t, NULL);

	return 0;
}

static void btf_fwd_type_log(struct btf_verifier_env *env,
			     const struct btf_type *t)
{
	btf_verifier_log(env, "%s", btf_type_kflag(t) ? "union" : "struct");
}

static struct btf_kind_operations fwd_ops = {
	.check_meta = btf_fwd_check_meta,
	.resolve = btf_df_resolve,
	.check_member = btf_df_check_member,
	.check_kflag_member = btf_df_check_kflag_member,
	.log_details = btf_fwd_type_log,
	.seq_show = btf_df_seq_show,
};

static int btf_array_check_member(struct btf_verifier_env *env,
				  const struct btf_type *struct_type,
				  const struct btf_member *member,
				  const struct btf_type *member_type)
{
	u32 struct_bits_off = member->offset;
	u32 struct_size, bytes_offset;
	u32 array_type_id, array_size;
	struct btf *btf = env->btf;

	if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
		btf_verifier_log_member(env, struct_type, member,
					"Member is not byte aligned");
		return -EINVAL;
	}

	array_type_id = member->type;
	btf_type_id_size(btf, &array_type_id, &array_size);
	struct_size = struct_type->size;
	bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
	if (struct_size - bytes_offset < array_size) {
		btf_verifier_log_member(env, struct_type, member,
					"Member exceeds struct_size");
		return -EINVAL;
	}

	return 0;
}

static s32 btf_array_check_meta(struct btf_verifier_env *env,
				const struct btf_type *t,
				u32 meta_left)
{
	const struct btf_array *array = btf_type_array(t);
	u32 meta_needed = sizeof(*array);

	if (meta_left < meta_needed) {
		btf_verifier_log_basic(env, t,
				       "meta_left:%u meta_needed:%u",
				       meta_left, meta_needed);
		return -EINVAL;
	}

	/* array type should not have a name */
	if (t->name_off) {
		btf_verifier_log_type(env, t, "Invalid name");
		return -EINVAL;
	}

	if (btf_type_vlen(t)) {
		btf_verifier_log_type(env, t, "vlen != 0");
		return -EINVAL;
	}

	if (btf_type_kflag(t)) {
		btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
		return -EINVAL;
	}

	if (t->size) {
		btf_verifier_log_type(env, t, "size != 0");
		return -EINVAL;
	}

	/* Array elem type and index type cannot be in type void,
	 * so !array->type and !array->index_type are not allowed.
	 */
	if (!array->type || !BTF_TYPE_ID_VALID(array->type)) {
		btf_verifier_log_type(env, t, "Invalid elem");
		return -EINVAL;
	}

	if (!array->index_type || !BTF_TYPE_ID_VALID(array->index_type)) {
		btf_verifier_log_type(env, t, "Invalid index");
		return -EINVAL;
	}

	btf_verifier_log_type(env, t, NULL);

	return meta_needed;
}

static int btf_array_resolve(struct btf_verifier_env *env,
			     const struct resolve_vertex *v)
{
	const struct btf_array *array = btf_type_array(v->t);
	const struct btf_type *elem_type, *index_type;
	u32 elem_type_id, index_type_id;
	struct btf *btf = env->btf;
	u32 elem_size;

	/* Check array->index_type */
	index_type_id = array->index_type;
	index_type = btf_type_by_id(btf, index_type_id);
	if (btf_type_nosize_or_null(index_type) ||
	    btf_type_is_resolve_source_only(index_type)) {
		btf_verifier_log_type(env, v->t, "Invalid index");
		return -EINVAL;
	}

	if (!env_type_is_resolve_sink(env, index_type) &&
	    !env_type_is_resolved(env, index_type_id))
		return env_stack_push(env, index_type, index_type_id);

	index_type = btf_type_id_size(btf, &index_type_id, NULL);
	if (!index_type || !btf_type_is_int(index_type) ||
	    !btf_type_int_is_regular(index_type)) {
		btf_verifier_log_type(env, v->t, "Invalid index");
		return -EINVAL;
	}

	/* Check array->type */
	elem_type_id = array->type;
	elem_type = btf_type_by_id(btf, elem_type_id);
	if (btf_type_nosize_or_null(elem_type) ||
	    btf_type_is_resolve_source_only(elem_type)) {
		btf_verifier_log_type(env, v->t,
				      "Invalid elem");
		return -EINVAL;
	}

	if (!env_type_is_resolve_sink(env, elem_type) &&
	    !env_type_is_resolved(env, elem_type_id))
		return env_stack_push(env, elem_type, elem_type_id);

	elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
	if (!elem_type) {
		btf_verifier_log_type(env, v->t, "Invalid elem");
		return -EINVAL;
	}

	if (btf_type_is_int(elem_type) && !btf_type_int_is_regular(elem_type)) {
		btf_verifier_log_type(env, v->t, "Invalid array of int");
		return -EINVAL;
	}

	if (array->nelems && elem_size > U32_MAX / array->nelems) {
		btf_verifier_log_type(env, v->t,
				      "Array size overflows U32_MAX");
		return -EINVAL;
	}

	env_stack_pop_resolved(env, elem_type_id, elem_size * array->nelems);

	return 0;
}

static void btf_array_log(struct btf_verifier_env *env,
			  const struct btf_type *t)
{
	const struct btf_array *array = btf_type_array(t);

	btf_verifier_log(env, "type_id=%u index_type_id=%u nr_elems=%u",
			 array->type, array->index_type, array->nelems);
}

static void btf_array_seq_show(const struct btf *btf, const struct btf_type *t,
			       u32 type_id, void *data, u8 bits_offset,
			       struct seq_file *m)
{
	const struct btf_array *array = btf_type_array(t);
	const struct btf_kind_operations *elem_ops;
	const struct btf_type *elem_type;
	u32 i, elem_size, elem_type_id;

	elem_type_id = array->type;
	elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
	elem_ops = btf_type_ops(elem_type);
	seq_puts(m, "[");
	for (i = 0; i < array->nelems; i++) {
		if (i)
			seq_puts(m, ",");

		elem_ops->seq_show(btf, elem_type, elem_type_id, data,
				   bits_offset, m);
		data += elem_size;
	}
	seq_puts(m, "]");
}

static struct btf_kind_operations array_ops = {
	.check_meta = btf_array_check_meta,
	.resolve = btf_array_resolve,
	.check_member = btf_array_check_member,
	.check_kflag_member = btf_generic_check_kflag_member,
	.log_details = btf_array_log,
	.seq_show = btf_array_seq_show,
};

static int btf_struct_check_member(struct btf_verifier_env *env,
				   const struct btf_type *struct_type,
				   const struct btf_member *member,
				   const struct btf_type *member_type)
{
	u32 struct_bits_off = member->offset;
	u32 struct_size, bytes_offset;

	if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
		btf_verifier_log_member(env, struct_type, member,
					"Member is not byte aligned");
		return -EINVAL;
	}

	struct_size = struct_type->size;
	bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
	if (struct_size - bytes_offset < member_type->size) {
		btf_verifier_log_member(env, struct_type, member,
					"Member exceeds struct_size");
		return -EINVAL;
	}

	return 0;
}

static s32 btf_struct_check_meta(struct btf_verifier_env *env,
				 const struct btf_type *t,
				 u32 meta_left)
{
	bool is_union = BTF_INFO_KIND(t->info) == BTF_KIND_UNION;
	const struct btf_member *member;
	u32 meta_needed, last_offset;
	struct btf *btf = env->btf;
	u32 struct_size = t->size;
	u32 offset;
	u16 i;

	meta_needed = btf_type_vlen(t) * sizeof(*member);
	if (meta_left < meta_needed) {
		btf_verifier_log_basic(env, t,
				       "meta_left:%u meta_needed:%u",
				       meta_left, meta_needed);
		return -EINVAL;
	}

	/* struct type either no name or a valid one */
	if (t->name_off &&
	    !btf_name_valid_identifier(env->btf, t->name_off)) {
		btf_verifier_log_type(env, t, "Invalid name");
		return -EINVAL;
	}

	btf_verifier_log_type(env, t, NULL);

	last_offset = 0;
	for_each_member(i, t, member) {
		if (!btf_name_offset_valid(btf, member->name_off)) {
			btf_verifier_log_member(env, t, member,
						"Invalid member name_offset:%u",
						member->name_off);
			return -EINVAL;
		}

		/* struct member either no name or a valid one */
		if (member->name_off &&
		    !btf_name_valid_identifier(btf, member->name_off)) {
			btf_verifier_log_member(env, t, member, "Invalid name");
			return -EINVAL;
		}
		/* A member cannot be in type void */
		if (!member->type || !BTF_TYPE_ID_VALID(member->type)) {
			btf_verifier_log_member(env, t, member,
						"Invalid type_id");
			return -EINVAL;
		}

		offset = btf_member_bit_offset(t, member);
		if (is_union && offset) {
			btf_verifier_log_member(env, t, member,
						"Invalid member bits_offset");
			return -EINVAL;
		}

		/*
		 * ">" instead of ">=" because the last member could be
		 * "char a[0];"
		 */
		if (last_offset > offset) {
			btf_verifier_log_member(env, t, member,
						"Invalid member bits_offset");
			return -EINVAL;
		}

		if (BITS_ROUNDUP_BYTES(offset) > struct_size) {
			btf_verifier_log_member(env, t, member,
						"Member bits_offset exceeds its struct size");
			return -EINVAL;
		}

		btf_verifier_log_member(env, t, member, NULL);
		last_offset = offset;
	}

	return meta_needed;
}

static int btf_struct_resolve(struct btf_verifier_env *env,
			      const struct resolve_vertex *v)
{
	const struct btf_member *member;
	int err;
	u16 i;

	/* Before continue resolving the next_member,
	 * ensure the last member is indeed resolved to a
	 * type with size info.
	 */
	if (v->next_member) {
		const struct btf_type *last_member_type;
		const struct btf_member *last_member;
		u16 last_member_type_id;

		last_member = btf_type_member(v->t) + v->next_member - 1;
		last_member_type_id = last_member->type;
		if (WARN_ON_ONCE(!env_type_is_resolved(env,
						       last_member_type_id)))
			return -EINVAL;

		last_member_type = btf_type_by_id(env->btf,
						  last_member_type_id);
		if (btf_type_kflag(v->t))
			err = btf_type_ops(last_member_type)->check_kflag_member(env, v->t,
								last_member,
								last_member_type);
		else
			err = btf_type_ops(last_member_type)->check_member(env, v->t,
								last_member,
								last_member_type);
		if (err)
			return err;
	}

	for_each_member_from(i, v->next_member, v->t, member) {
		u32 member_type_id = member->type;
		const struct btf_type *member_type = btf_type_by_id(env->btf,
								member_type_id);

		if (btf_type_nosize_or_null(member_type) ||
		    btf_type_is_resolve_source_only(member_type)) {
			btf_verifier_log_member(env, v->t, member,
						"Invalid member");
			return -EINVAL;
		}

		if (!env_type_is_resolve_sink(env, member_type) &&
		    !env_type_is_resolved(env, member_type_id)) {
			env_stack_set_next_member(env, i + 1);
			return env_stack_push(env, member_type, member_type_id);
		}

		if (btf_type_kflag(v->t))
			err = btf_type_ops(member_type)->check_kflag_member(env, v->t,
									    member,
									    member_type);
		else
			err = btf_type_ops(member_type)->check_member(env, v->t,
								      member,
								      member_type);
		if (err)
			return err;
	}

	env_stack_pop_resolved(env, 0, 0);

	return 0;
}

static void btf_struct_log(struct btf_verifier_env *env,
			   const struct btf_type *t)
{
	btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
}

/* find 'struct bpf_spin_lock' in map value.
 * return >= 0 offset if found
 * and < 0 in case of error
 */
int btf_find_spin_lock(const struct btf *btf, const struct btf_type *t)
{
	const struct btf_member *member;
	u32 i, off = -ENOENT;

	if (!__btf_type_is_struct(t))
		return -EINVAL;

	for_each_member(i, t, member) {
		const struct btf_type *member_type = btf_type_by_id(btf,
								    member->type);
		if (!__btf_type_is_struct(member_type))
			continue;
		if (member_type->size != sizeof(struct bpf_spin_lock))
			continue;
		if (strcmp(__btf_name_by_offset(btf, member_type->name_off),
			   "bpf_spin_lock"))
			continue;
		if (off != -ENOENT)
			/* only one 'struct bpf_spin_lock' is allowed */
			return -E2BIG;
		off = btf_member_bit_offset(t, member);
		if (off % 8)
			/* valid C code cannot generate such BTF */
			return -EINVAL;
		off /= 8;
		if (off % __alignof__(struct bpf_spin_lock))
			/* valid struct bpf_spin_lock will be 4 byte aligned */
			return -EINVAL;
	}
	return off;
}

static void btf_struct_seq_show(const struct btf *btf, const struct btf_type *t,
				u32 type_id, void *data, u8 bits_offset,
				struct seq_file *m)
{
	const char *seq = BTF_INFO_KIND(t->info) == BTF_KIND_UNION ? "|" : ",";
	const struct btf_member *member;
	u32 i;

	seq_puts(m, "{");
	for_each_member(i, t, member) {
		const struct btf_type *member_type = btf_type_by_id(btf,
								member->type);
		const struct btf_kind_operations *ops;
		u32 member_offset, bitfield_size;
		u32 bytes_offset;
		u8 bits8_offset;

		if (i)
			seq_puts(m, seq);

		member_offset = btf_member_bit_offset(t, member);
		bitfield_size = btf_member_bitfield_size(t, member);
		bytes_offset = BITS_ROUNDDOWN_BYTES(member_offset);
		bits8_offset = BITS_PER_BYTE_MASKED(member_offset);
		if (bitfield_size) {
			btf_bitfield_seq_show(data + bytes_offset, bits8_offset,
					      bitfield_size, m);
		} else {
			ops = btf_type_ops(member_type);
			ops->seq_show(btf, member_type, member->type,
				      data + bytes_offset, bits8_offset, m);
		}
	}
	seq_puts(m, "}");
}

static struct btf_kind_operations struct_ops = {
	.check_meta = btf_struct_check_meta,
	.resolve = btf_struct_resolve,
	.check_member = btf_struct_check_member,
	.check_kflag_member = btf_generic_check_kflag_member,
	.log_details = btf_struct_log,
	.seq_show = btf_struct_seq_show,
};

static int btf_enum_check_member(struct btf_verifier_env *env,
				 const struct btf_type *struct_type,
				 const struct btf_member *member,
				 const struct btf_type *member_type)
{
	u32 struct_bits_off = member->offset;
	u32 struct_size, bytes_offset;

	if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
		btf_verifier_log_member(env, struct_type, member,
					"Member is not byte aligned");
		return -EINVAL;
	}

	struct_size = struct_type->size;
	bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
	if (struct_size - bytes_offset < sizeof(int)) {
		btf_verifier_log_member(env, struct_type, member,
					"Member exceeds struct_size");
		return -EINVAL;
	}

	return 0;
}

static int btf_enum_check_kflag_member(struct btf_verifier_env *env,
				       const struct btf_type *struct_type,
				       const struct btf_member *member,
				       const struct btf_type *member_type)
{
	u32 struct_bits_off, nr_bits, bytes_end, struct_size;
	u32 int_bitsize = sizeof(int) * BITS_PER_BYTE;

	struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset);
	nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset);
	if (!nr_bits) {
		if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
			btf_verifier_log_member(env, struct_type, member,
						"Member is not byte aligned");
			return -EINVAL;
		}

		nr_bits = int_bitsize;
	} else if (nr_bits > int_bitsize) {
		btf_verifier_log_member(env, struct_type, member,
					"Invalid member bitfield_size");
		return -EINVAL;
	}

	struct_size = struct_type->size;
	bytes_end = BITS_ROUNDUP_BYTES(struct_bits_off + nr_bits);
	if (struct_size < bytes_end) {
		btf_verifier_log_member(env, struct_type, member,
					"Member exceeds struct_size");
		return -EINVAL;
	}

	return 0;
}

static s32 btf_enum_check_meta(struct btf_verifier_env *env,
			       const struct btf_type *t,
			       u32 meta_left)
{
	const struct btf_enum *enums = btf_type_enum(t);
	struct btf *btf = env->btf;
	u16 i, nr_enums;
	u32 meta_needed;

	nr_enums = btf_type_vlen(t);
	meta_needed = nr_enums * sizeof(*enums);

	if (meta_left < meta_needed) {
		btf_verifier_log_basic(env, t,
				       "meta_left:%u meta_needed:%u",
				       meta_left, meta_needed);
		return -EINVAL;
	}

	if (btf_type_kflag(t)) {
		btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
		return -EINVAL;
	}

	if (t->size > 8 || !is_power_of_2(t->size)) {
		btf_verifier_log_type(env, t, "Unexpected size");
		return -EINVAL;
	}

	/* enum type either no name or a valid one */
	if (t->name_off &&
	    !btf_name_valid_identifier(env->btf, t->name_off)) {
		btf_verifier_log_type(env, t, "Invalid name");
		return -EINVAL;
	}

	btf_verifier_log_type(env, t, NULL);

	for (i = 0; i < nr_enums; i++) {
		if (!btf_name_offset_valid(btf, enums[i].name_off)) {
			btf_verifier_log(env, "\tInvalid name_offset:%u",
					 enums[i].name_off);
			return -EINVAL;
		}

		/* enum member must have a valid name */
		if (!enums[i].name_off ||
		    !btf_name_valid_identifier(btf, enums[i].name_off)) {
			btf_verifier_log_type(env, t, "Invalid name");
			return -EINVAL;
		}

		if (env->log.level == BPF_LOG_KERNEL)
			continue;
		btf_verifier_log(env, "\t%s val=%d\n",
				 __btf_name_by_offset(btf, enums[i].name_off),
				 enums[i].val);
	}

	return meta_needed;
}

static void btf_enum_log(struct btf_verifier_env *env,
			 const struct btf_type *t)
{
	btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
}

static void btf_enum_seq_show(const struct btf *btf, const struct btf_type *t,
			      u32 type_id, void *data, u8 bits_offset,
			      struct seq_file *m)
{
	const struct btf_enum *enums = btf_type_enum(t);
	u32 i, nr_enums = btf_type_vlen(t);
	int v = *(int *)data;

	for (i = 0; i < nr_enums; i++) {
		if (v == enums[i].val) {
			seq_printf(m, "%s",
				   __btf_name_by_offset(btf,
							enums[i].name_off));
			return;
		}
	}

	seq_printf(m, "%d", v);
}

static struct btf_kind_operations enum_ops = {
	.check_meta = btf_enum_check_meta,
	.resolve = btf_df_resolve,
	.check_member = btf_enum_check_member,
	.check_kflag_member = btf_enum_check_kflag_member,
	.log_details = btf_enum_log,
	.seq_show = btf_enum_seq_show,
};

static s32 btf_func_proto_check_meta(struct btf_verifier_env *env,
				     const struct btf_type *t,
				     u32 meta_left)
{
	u32 meta_needed = btf_type_vlen(t) * sizeof(struct btf_param);

	if (meta_left < meta_needed) {
		btf_verifier_log_basic(env, t,
				       "meta_left:%u meta_needed:%u",
				       meta_left, meta_needed);
		return -EINVAL;
	}

	if (t->name_off) {
		btf_verifier_log_type(env, t, "Invalid name");
		return -EINVAL;
	}

	if (btf_type_kflag(t)) {
		btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
		return -EINVAL;
	}

	btf_verifier_log_type(env, t, NULL);

	return meta_needed;
}

static void btf_func_proto_log(struct btf_verifier_env *env,
			       const struct btf_type *t)
{
	const struct btf_param *args = (const struct btf_param *)(t + 1);
	u16 nr_args = btf_type_vlen(t), i;

	btf_verifier_log(env, "return=%u args=(", t->type);
	if (!nr_args) {
		btf_verifier_log(env, "void");
		goto done;
	}

	if (nr_args == 1 && !args[0].type) {
		/* Only one vararg */
		btf_verifier_log(env, "vararg");
		goto done;
	}

	btf_verifier_log(env, "%u %s", args[0].type,
			 __btf_name_by_offset(env->btf,
					      args[0].name_off));
	for (i = 1; i < nr_args - 1; i++)
		btf_verifier_log(env, ", %u %s", args[i].type,
				 __btf_name_by_offset(env->btf,
						      args[i].name_off));

	if (nr_args > 1) {
		const struct btf_param *last_arg = &args[nr_args - 1];

		if (last_arg->type)
			btf_verifier_log(env, ", %u %s", last_arg->type,
					 __btf_name_by_offset(env->btf,
							      last_arg->name_off));
		else
			btf_verifier_log(env, ", vararg");
	}

done:
	btf_verifier_log(env, ")");
}

static struct btf_kind_operations func_proto_ops = {
	.check_meta = btf_func_proto_check_meta,
	.resolve = btf_df_resolve,
	/*
	 * BTF_KIND_FUNC_PROTO cannot be directly referred by
	 * a struct's member.
	 *
	 * It should be a funciton pointer instead.
	 * (i.e. struct's member -> BTF_KIND_PTR -> BTF_KIND_FUNC_PROTO)
	 *
	 * Hence, there is no btf_func_check_member().
	 */
	.check_member = btf_df_check_member,
	.check_kflag_member = btf_df_check_kflag_member,
	.log_details = btf_func_proto_log,
	.seq_show = btf_df_seq_show,
};

static s32 btf_func_check_meta(struct btf_verifier_env *env,
			       const struct btf_type *t,
			       u32 meta_left)
{
	if (!t->name_off ||
	    !btf_name_valid_identifier(env->btf, t->name_off)) {
		btf_verifier_log_type(env, t, "Invalid name");
		return -EINVAL;
	}

	if (btf_type_vlen(t)) {
		btf_verifier_log_type(env, t, "vlen != 0");
		return -EINVAL;
	}

	if (btf_type_kflag(t)) {
		btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
		return -EINVAL;
	}

	btf_verifier_log_type(env, t, NULL);

	return 0;
}

static struct btf_kind_operations func_ops = {
	.check_meta = btf_func_check_meta,
	.resolve = btf_df_resolve,
	.check_member = btf_df_check_member,
	.check_kflag_member = btf_df_check_kflag_member,
	.log_details = btf_ref_type_log,
	.seq_show = btf_df_seq_show,
};

static s32 btf_var_check_meta(struct btf_verifier_env *env,
			      const struct btf_type *t,
			      u32 meta_left)
{
	const struct btf_var *var;
	u32 meta_needed = sizeof(*var);

	if (meta_left < meta_needed) {
		btf_verifier_log_basic(env, t,
				       "meta_left:%u meta_needed:%u",
				       meta_left, meta_needed);
		return -EINVAL;
	}

	if (btf_type_vlen(t)) {
		btf_verifier_log_type(env, t, "vlen != 0");
		return -EINVAL;
	}

	if (btf_type_kflag(t)) {
		btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
		return -EINVAL;
	}

	if (!t->name_off ||
	    !__btf_name_valid(env->btf, t->name_off, true)) {
		btf_verifier_log_type(env, t, "Invalid name");
		return -EINVAL;
	}

	/* A var cannot be in type void */
	if (!t->type || !BTF_TYPE_ID_VALID(t->type)) {
		btf_verifier_log_type(env, t, "Invalid type_id");
		return -EINVAL;
	}

	var = btf_type_var(t);
	if (var->linkage != BTF_VAR_STATIC &&
	    var->linkage != BTF_VAR_GLOBAL_ALLOCATED) {
		btf_verifier_log_type(env, t, "Linkage not supported");
		return -EINVAL;
	}

	btf_verifier_log_type(env, t, NULL);

	return meta_needed;
}

static void btf_var_log(struct btf_verifier_env *env, const struct btf_type *t)
{
	const struct btf_var *var = btf_type_var(t);

	btf_verifier_log(env, "type_id=%u linkage=%u", t->type, var->linkage);
}

static const struct btf_kind_operations var_ops = {
	.check_meta		= btf_var_check_meta,
	.resolve		= btf_var_resolve,
	.check_member		= btf_df_check_member,
	.check_kflag_member	= btf_df_check_kflag_member,
	.log_details		= btf_var_log,
	.seq_show		= btf_var_seq_show,
};

static s32 btf_datasec_check_meta(struct btf_verifier_env *env,
				  const struct btf_type *t,
				  u32 meta_left)
{
	const struct btf_var_secinfo *vsi;
	u64 last_vsi_end_off = 0, sum = 0;
	u32 i, meta_needed;

	meta_needed = btf_type_vlen(t) * sizeof(*vsi);
	if (meta_left < meta_needed) {
		btf_verifier_log_basic(env, t,
				       "meta_left:%u meta_needed:%u",
				       meta_left, meta_needed);
		return -EINVAL;
	}

	if (!btf_type_vlen(t)) {
		btf_verifier_log_type(env, t, "vlen == 0");
		return -EINVAL;
	}

	if (!t->size) {
		btf_verifier_log_type(env, t, "size == 0");
		return -EINVAL;
	}

	if (btf_type_kflag(t)) {
		btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
		return -EINVAL;
	}

	if (!t->name_off ||
	    !btf_name_valid_section(env->btf, t->name_off)) {
		btf_verifier_log_type(env, t, "Invalid name");
		return -EINVAL;
	}

	btf_verifier_log_type(env, t, NULL);

	for_each_vsi(i, t, vsi) {
		/* A var cannot be in type void */
		if (!vsi->type || !BTF_TYPE_ID_VALID(vsi->type)) {
			btf_verifier_log_vsi(env, t, vsi,
					     "Invalid type_id");
			return -EINVAL;
		}

		if (vsi->offset < last_vsi_end_off || vsi->offset >= t->size) {
			btf_verifier_log_vsi(env, t, vsi,
					     "Invalid offset");
			return -EINVAL;
		}

		if (!vsi->size || vsi->size > t->size) {
			btf_verifier_log_vsi(env, t, vsi,
					     "Invalid size");
			return -EINVAL;
		}

		last_vsi_end_off = vsi->offset + vsi->size;
		if (last_vsi_end_off > t->size) {
			btf_verifier_log_vsi(env, t, vsi,
					     "Invalid offset+size");
			return -EINVAL;
		}

		btf_verifier_log_vsi(env, t, vsi, NULL);
		sum += vsi->size;
	}

	if (t->size < sum) {
		btf_verifier_log_type(env, t, "Invalid btf_info size");
		return -EINVAL;
	}

	return meta_needed;
}

static int btf_datasec_resolve(struct btf_verifier_env *env,
			       const struct resolve_vertex *v)
{
	const struct btf_var_secinfo *vsi;
	struct btf *btf = env->btf;
	u16 i;

	for_each_vsi_from(i, v->next_member, v->t, vsi) {
		u32 var_type_id = vsi->type, type_id, type_size = 0;
		const struct btf_type *var_type = btf_type_by_id(env->btf,
								 var_type_id);
		if (!var_type || !btf_type_is_var(var_type)) {
			btf_verifier_log_vsi(env, v->t, vsi,
					     "Not a VAR kind member");
			return -EINVAL;
		}

		if (!env_type_is_resolve_sink(env, var_type) &&
		    !env_type_is_resolved(env, var_type_id)) {
			env_stack_set_next_member(env, i + 1);
			return env_stack_push(env, var_type, var_type_id);
		}

		type_id = var_type->type;
		if (!btf_type_id_size(btf, &type_id, &type_size)) {
			btf_verifier_log_vsi(env, v->t, vsi, "Invalid type");
			return -EINVAL;
		}

		if (vsi->size < type_size) {
			btf_verifier_log_vsi(env, v->t, vsi, "Invalid size");
			return -EINVAL;
		}
	}

	env_stack_pop_resolved(env, 0, 0);
	return 0;
}

static void btf_datasec_log(struct btf_verifier_env *env,
			    const struct btf_type *t)
{
	btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
}

static void btf_datasec_seq_show(const struct btf *btf,
				 const struct btf_type *t, u32 type_id,
				 void *data, u8 bits_offset,
				 struct seq_file *m)
{
	const struct btf_var_secinfo *vsi;
	const struct btf_type *var;
	u32 i;

	seq_printf(m, "section (\"%s\") = {", __btf_name_by_offset(btf, t->name_off));
	for_each_vsi(i, t, vsi) {
		var = btf_type_by_id(btf, vsi->type);
		if (i)
			seq_puts(m, ",");
		btf_type_ops(var)->seq_show(btf, var, vsi->type,
					    data + vsi->offset, bits_offset, m);
	}
	seq_puts(m, "}");
}

static const struct btf_kind_operations datasec_ops = {
	.check_meta		= btf_datasec_check_meta,
	.resolve		= btf_datasec_resolve,
	.check_member		= btf_df_check_member,
	.check_kflag_member	= btf_df_check_kflag_member,
	.log_details		= btf_datasec_log,
	.seq_show		= btf_datasec_seq_show,
};

static int btf_func_proto_check(struct btf_verifier_env *env,
				const struct btf_type *t)
{
	const struct btf_type *ret_type;
	const struct btf_param *args;
	const struct btf *btf;
	u16 nr_args, i;
	int err;

	btf = env->btf;
	args = (const struct btf_param *)(t + 1);
	nr_args = btf_type_vlen(t);

	/* Check func return type which could be "void" (t->type == 0) */
	if (t->type) {
		u32 ret_type_id = t->type;

		ret_type = btf_type_by_id(btf, ret_type_id);
		if (!ret_type) {
			btf_verifier_log_type(env, t, "Invalid return type");
			return -EINVAL;
		}

		if (btf_type_needs_resolve(ret_type) &&
		    !env_type_is_resolved(env, ret_type_id)) {
			err = btf_resolve(env, ret_type, ret_type_id);
			if (err)
				return err;
		}

		/* Ensure the return type is a type that has a size */
		if (!btf_type_id_size(btf, &ret_type_id, NULL)) {
			btf_verifier_log_type(env, t, "Invalid return type");
			return -EINVAL;
		}
	}

	if (!nr_args)
		return 0;

	/* Last func arg type_id could be 0 if it is a vararg */
	if (!args[nr_args - 1].type) {
		if (args[nr_args - 1].name_off) {
			btf_verifier_log_type(env, t, "Invalid arg#%u",
					      nr_args);
			return -EINVAL;
		}
		nr_args--;
	}

	err = 0;
	for (i = 0; i < nr_args; i++) {
		const struct btf_type *arg_type;
		u32 arg_type_id;

		arg_type_id = args[i].type;
		arg_type = btf_type_by_id(btf, arg_type_id);
		if (!arg_type) {
			btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
			err = -EINVAL;
			break;
		}

		if (args[i].name_off &&
		    (!btf_name_offset_valid(btf, args[i].name_off) ||
		     !btf_name_valid_identifier(btf, args[i].name_off))) {
			btf_verifier_log_type(env, t,
					      "Invalid arg#%u", i + 1);
			err = -EINVAL;
			break;
		}

		if (btf_type_needs_resolve(arg_type) &&
		    !env_type_is_resolved(env, arg_type_id)) {
			err = btf_resolve(env, arg_type, arg_type_id);
			if (err)
				break;
		}

		if (!btf_type_id_size(btf, &arg_type_id, NULL)) {
			btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
			err = -EINVAL;
			break;
		}
	}

	return err;
}

static int btf_func_check(struct btf_verifier_env *env,
			  const struct btf_type *t)
{
	const struct btf_type *proto_type;
	const struct btf_param *args;
	const struct btf *btf;
	u16 nr_args, i;

	btf = env->btf;
	proto_type = btf_type_by_id(btf, t->type);

	if (!proto_type || !btf_type_is_func_proto(proto_type)) {
		btf_verifier_log_type(env, t, "Invalid type_id");
		return -EINVAL;
	}

	args = (const struct btf_param *)(proto_type + 1);
	nr_args = btf_type_vlen(proto_type);
	for (i = 0; i < nr_args; i++) {
		if (!args[i].name_off && args[i].type) {
			btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
			return -EINVAL;
		}
	}

	return 0;
}

static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS] = {
	[BTF_KIND_INT] = &int_ops,
	[BTF_KIND_PTR] = &ptr_ops,
	[BTF_KIND_ARRAY] = &array_ops,
	[BTF_KIND_STRUCT] = &struct_ops,
	[BTF_KIND_UNION] = &struct_ops,
	[BTF_KIND_ENUM] = &enum_ops,
	[BTF_KIND_FWD] = &fwd_ops,
	[BTF_KIND_TYPEDEF] = &modifier_ops,
	[BTF_KIND_VOLATILE] = &modifier_ops,
	[BTF_KIND_CONST] = &modifier_ops,
	[BTF_KIND_RESTRICT] = &modifier_ops,
	[BTF_KIND_FUNC] = &func_ops,
	[BTF_KIND_FUNC_PROTO] = &func_proto_ops,
	[BTF_KIND_VAR] = &var_ops,
	[BTF_KIND_DATASEC] = &datasec_ops,
};

static s32 btf_check_meta(struct btf_verifier_env *env,
			  const struct btf_type *t,
			  u32 meta_left)
{
	u32 saved_meta_left = meta_left;
	s32 var_meta_size;

	if (meta_left < sizeof(*t)) {
		btf_verifier_log(env, "[%u] meta_left:%u meta_needed:%zu",
				 env->log_type_id, meta_left, sizeof(*t));
		return -EINVAL;
	}
	meta_left -= sizeof(*t);

	if (t->info & ~BTF_INFO_MASK) {
		btf_verifier_log(env, "[%u] Invalid btf_info:%x",
				 env->log_type_id, t->info);
		return -EINVAL;
	}

	if (BTF_INFO_KIND(t->info) > BTF_KIND_MAX ||
	    BTF_INFO_KIND(t->info) == BTF_KIND_UNKN) {
		btf_verifier_log(env, "[%u] Invalid kind:%u",
				 env->log_type_id, BTF_INFO_KIND(t->info));
		return -EINVAL;
	}

	if (!btf_name_offset_valid(env->btf, t->name_off)) {
		btf_verifier_log(env, "[%u] Invalid name_offset:%u",
				 env->log_type_id, t->name_off);
		return -EINVAL;
	}

	var_meta_size = btf_type_ops(t)->check_meta(env, t, meta_left);
	if (var_meta_size < 0)
		return var_meta_size;

	meta_left -= var_meta_size;

	return saved_meta_left - meta_left;
}

static int btf_check_all_metas(struct btf_verifier_env *env)
{
	struct btf *btf = env->btf;
	struct btf_header *hdr;
	void *cur, *end;

	hdr = &btf->hdr;
	cur = btf->nohdr_data + hdr->type_off;
	end = cur + hdr->type_len;

	env->log_type_id = 1;
	while (cur < end) {
		struct btf_type *t = cur;
		s32 meta_size;

		meta_size = btf_check_meta(env, t, end - cur);
		if (meta_size < 0)
			return meta_size;

		btf_add_type(env, t);
		cur += meta_size;
		env->log_type_id++;
	}

	return 0;
}

static bool btf_resolve_valid(struct btf_verifier_env *env,
			      const struct btf_type *t,
			      u32 type_id)
{
	struct btf *btf = env->btf;

	if (!env_type_is_resolved(env, type_id))
		return false;

	if (btf_type_is_struct(t) || btf_type_is_datasec(t))
		return !btf->resolved_ids[type_id] &&
		       !btf->resolved_sizes[type_id];

	if (btf_type_is_modifier(t) || btf_type_is_ptr(t) ||
	    btf_type_is_var(t)) {
		t = btf_type_id_resolve(btf, &type_id);
		return t &&
		       !btf_type_is_modifier(t) &&
		       !btf_type_is_var(t) &&
		       !btf_type_is_datasec(t);
	}

	if (btf_type_is_array(t)) {
		const struct btf_array *array = btf_type_array(t);
		const struct btf_type *elem_type;
		u32 elem_type_id = array->type;
		u32 elem_size;

		elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
		return elem_type && !btf_type_is_modifier(elem_type) &&
			(array->nelems * elem_size ==
			 btf->resolved_sizes[type_id]);
	}

	return false;
}

static int btf_resolve(struct btf_verifier_env *env,
		       const struct btf_type *t, u32 type_id)
{
	u32 save_log_type_id = env->log_type_id;
	const struct resolve_vertex *v;
	int err = 0;

	env->resolve_mode = RESOLVE_TBD;
	env_stack_push(env, t, type_id);
	while (!err && (v = env_stack_peak(env))) {
		env->log_type_id = v->type_id;
		err = btf_type_ops(v->t)->resolve(env, v);
	}

	env->log_type_id = type_id;
	if (err == -E2BIG) {
		btf_verifier_log_type(env, t,
				      "Exceeded max resolving depth:%u",
				      MAX_RESOLVE_DEPTH);
	} else if (err == -EEXIST) {
		btf_verifier_log_type(env, t, "Loop detected");
	}

	/* Final sanity check */
	if (!err && !btf_resolve_valid(env, t, type_id)) {
		btf_verifier_log_type(env, t, "Invalid resolve state");
		err = -EINVAL;
	}

	env->log_type_id = save_log_type_id;
	return err;
}

static int btf_check_all_types(struct btf_verifier_env *env)
{
	struct btf *btf = env->btf;
	u32 type_id;
	int err;

	err = env_resolve_init(env);
	if (err)
		return err;

	env->phase++;
	for (type_id = 1; type_id <= btf->nr_types; type_id++) {
		const struct btf_type *t = btf_type_by_id(btf, type_id);

		env->log_type_id = type_id;
		if (btf_type_needs_resolve(t) &&
		    !env_type_is_resolved(env, type_id)) {
			err = btf_resolve(env, t, type_id);
			if (err)
				return err;
		}

		if (btf_type_is_func_proto(t)) {
			err = btf_func_proto_check(env, t);
			if (err)
				return err;
		}

		if (btf_type_is_func(t)) {
			err = btf_func_check(env, t);
			if (err)
				return err;
		}
	}

	return 0;
}

static int btf_parse_type_sec(struct btf_verifier_env *env)
{
	const struct btf_header *hdr = &env->btf->hdr;
	int err;

	/* Type section must align to 4 bytes */
	if (hdr->type_off & (sizeof(u32) - 1)) {
		btf_verifier_log(env, "Unaligned type_off");
		return -EINVAL;
	}

	if (!hdr->type_len) {
		btf_verifier_log(env, "No type found");
		return -EINVAL;
	}

	err = btf_check_all_metas(env);
	if (err)
		return err;

	return btf_check_all_types(env);
}

static int btf_parse_str_sec(struct btf_verifier_env *env)
{
	const struct btf_header *hdr;
	struct btf *btf = env->btf;
	const char *start, *end;

	hdr = &btf->hdr;
	start = btf->nohdr_data + hdr->str_off;
	end = start + hdr->str_len;

	if (end != btf->data + btf->data_size) {
		btf_verifier_log(env, "String section is not at the end");
		return -EINVAL;
	}

	if (!hdr->str_len || hdr->str_len - 1 > BTF_MAX_NAME_OFFSET ||
	    start[0] || end[-1]) {
		btf_verifier_log(env, "Invalid string section");
		return -EINVAL;
	}

	btf->strings = start;

	return 0;
}

static const size_t btf_sec_info_offset[] = {
	offsetof(struct btf_header, type_off),
	offsetof(struct btf_header, str_off),
};

static int btf_sec_info_cmp(const void *a, const void *b)
{
	const struct btf_sec_info *x = a;
	const struct btf_sec_info *y = b;

	return (int)(x->off - y->off) ? : (int)(x->len - y->len);
}

static int btf_check_sec_info(struct btf_verifier_env *env,
			      u32 btf_data_size)
{
	struct btf_sec_info secs[ARRAY_SIZE(btf_sec_info_offset)];
	u32 total, expected_total, i;
	const struct btf_header *hdr;
	const struct btf *btf;

	btf = env->btf;
	hdr = &btf->hdr;

	/* Populate the secs from hdr */
	for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++)
		secs[i] = *(struct btf_sec_info *)((void *)hdr +
						   btf_sec_info_offset[i]);

	sort(secs, ARRAY_SIZE(btf_sec_info_offset),
	     sizeof(struct btf_sec_info), btf_sec_info_cmp, NULL);

	/* Check for gaps and overlap among sections */
	total = 0;
	expected_total = btf_data_size - hdr->hdr_len;
	for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++) {
		if (expected_total < secs[i].off) {
			btf_verifier_log(env, "Invalid section offset");
			return -EINVAL;
		}
		if (total < secs[i].off) {
			/* gap */
			btf_verifier_log(env, "Unsupported section found");
			return -EINVAL;
		}
		if (total > secs[i].off) {
			btf_verifier_log(env, "Section overlap found");
			return -EINVAL;
		}
		if (expected_total - total < secs[i].len) {
			btf_verifier_log(env,
					 "Total section length too long");
			return -EINVAL;
		}
		total += secs[i].len;
	}

	/* There is data other than hdr and known sections */
	if (expected_total != total) {
		btf_verifier_log(env, "Unsupported section found");
		return -EINVAL;
	}

	return 0;
}

static int btf_parse_hdr(struct btf_verifier_env *env)
{
	u32 hdr_len, hdr_copy, btf_data_size;
	const struct btf_header *hdr;
	struct btf *btf;
	int err;

	btf = env->btf;
	btf_data_size = btf->data_size;

	if (btf_data_size <
	    offsetof(struct btf_header, hdr_len) + sizeof(hdr->hdr_len)) {
		btf_verifier_log(env, "hdr_len not found");
		return -EINVAL;
	}

	hdr = btf->data;
	hdr_len = hdr->hdr_len;
	if (btf_data_size < hdr_len) {
		btf_verifier_log(env, "btf_header not found");
		return -EINVAL;
	}

	/* Ensure the unsupported header fields are zero */
	if (hdr_len > sizeof(btf->hdr)) {
		u8 *expected_zero = btf->data + sizeof(btf->hdr);
		u8 *end = btf->data + hdr_len;

		for (; expected_zero < end; expected_zero++) {
			if (*expected_zero) {
				btf_verifier_log(env, "Unsupported btf_header");
				return -E2BIG;
			}
		}
	}

	hdr_copy = min_t(u32, hdr_len, sizeof(btf->hdr));
	memcpy(&btf->hdr, btf->data, hdr_copy);

	hdr = &btf->hdr;

	btf_verifier_log_hdr(env, btf_data_size);

	if (hdr->magic != BTF_MAGIC) {
		btf_verifier_log(env, "Invalid magic");
		return -EINVAL;
	}

	if (hdr->version != BTF_VERSION) {
		btf_verifier_log(env, "Unsupported version");
		return -ENOTSUPP;
	}

	if (hdr->flags) {
		btf_verifier_log(env, "Unsupported flags");
		return -ENOTSUPP;
	}

	if (btf_data_size == hdr->hdr_len) {
		btf_verifier_log(env, "No data");
		return -EINVAL;
	}

	err = btf_check_sec_info(env, btf_data_size);
	if (err)
		return err;

	return 0;
}

static struct btf *btf_parse(void __user *btf_data, u32 btf_data_size,
			     u32 log_level, char __user *log_ubuf, u32 log_size)
{
	struct btf_verifier_env *env = NULL;
	struct bpf_verifier_log *log;
	struct btf *btf = NULL;
	u8 *data;
	int err;

	if (btf_data_size > BTF_MAX_SIZE)
		return ERR_PTR(-E2BIG);

	env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
	if (!env)
		return ERR_PTR(-ENOMEM);

	log = &env->log;
	if (log_level || log_ubuf || log_size) {
		/* user requested verbose verifier output
		 * and supplied buffer to store the verification trace
		 */
		log->level = log_level;
		log->ubuf = log_ubuf;
		log->len_total = log_size;

		/* log attributes have to be sane */
		if (log->len_total < 128 || log->len_total > UINT_MAX >> 8 ||
		    !log->level || !log->ubuf) {
			err = -EINVAL;
			goto errout;
		}
	}

	btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
	if (!btf) {
		err = -ENOMEM;
		goto errout;
	}
	env->btf = btf;

	data = kvmalloc(btf_data_size, GFP_KERNEL | __GFP_NOWARN);
	if (!data) {
		err = -ENOMEM;
		goto errout;
	}

	btf->data = data;
	btf->data_size = btf_data_size;

	if (copy_from_user(data, btf_data, btf_data_size)) {
		err = -EFAULT;
		goto errout;
	}

	err = btf_parse_hdr(env);
	if (err)
		goto errout;

	btf->nohdr_data = btf->data + btf->hdr.hdr_len;

	err = btf_parse_str_sec(env);
	if (err)
		goto errout;

	err = btf_parse_type_sec(env);
	if (err)
		goto errout;

	if (log->level && bpf_verifier_log_full(log)) {
		err = -ENOSPC;
		goto errout;
	}

	btf_verifier_env_free(env);
	refcount_set(&btf->refcnt, 1);
	return btf;

errout:
	btf_verifier_env_free(env);
	if (btf)
		btf_free(btf);
	return ERR_PTR(err);
}

extern char __weak _binary__btf_vmlinux_bin_start[];
extern char __weak _binary__btf_vmlinux_bin_end[];
extern struct btf *btf_vmlinux;

#define BPF_MAP_TYPE(_id, _ops)
static union {
	struct bpf_ctx_convert {
#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
	prog_ctx_type _id##_prog; \
	kern_ctx_type _id##_kern;
#include <linux/bpf_types.h>
#undef BPF_PROG_TYPE
	} *__t;
	/* 't' is written once under lock. Read many times. */
	const struct btf_type *t;
} bpf_ctx_convert;
enum {
#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
	__ctx_convert##_id,
#include <linux/bpf_types.h>
#undef BPF_PROG_TYPE
	__ctx_convert_unused, /* to avoid empty enum in extreme .config */
};
static u8 bpf_ctx_convert_map[] = {
#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
	[_id] = __ctx_convert##_id,
#include <linux/bpf_types.h>
#undef BPF_PROG_TYPE
};
#undef BPF_MAP_TYPE

static const struct btf_member *
btf_get_prog_ctx_type(struct bpf_verifier_log *log, struct btf *btf,
		      const struct btf_type *t, enum bpf_prog_type prog_type)
{
	const struct btf_type *conv_struct;
	const struct btf_type *ctx_struct;
	const struct btf_member *ctx_type;
	const char *tname, *ctx_tname;

	conv_struct = bpf_ctx_convert.t;
	if (!conv_struct) {
		bpf_log(log, "btf_vmlinux is malformed\n");
		return NULL;
	}
	t = btf_type_by_id(btf, t->type);
	while (btf_type_is_modifier(t))
		t = btf_type_by_id(btf, t->type);
	if (!btf_type_is_struct(t)) {
		/* Only pointer to struct is supported for now.
		 * That means that BPF_PROG_TYPE_TRACEPOINT with BTF
		 * is not supported yet.
		 * BPF_PROG_TYPE_RAW_TRACEPOINT is fine.
		 */
		bpf_log(log, "BPF program ctx type is not a struct\n");
		return NULL;
	}
	tname = btf_name_by_offset(btf, t->name_off);
	if (!tname) {
		bpf_log(log, "BPF program ctx struct doesn't have a name\n");
		return NULL;
	}
	/* prog_type is valid bpf program type. No need for bounds check. */
	ctx_type = btf_type_member(conv_struct) + bpf_ctx_convert_map[prog_type] * 2;
	/* ctx_struct is a pointer to prog_ctx_type in vmlinux.
	 * Like 'struct __sk_buff'
	 */
	ctx_struct = btf_type_by_id(btf_vmlinux, ctx_type->type);
	if (!ctx_struct)
		/* should not happen */
		return NULL;
	ctx_tname = btf_name_by_offset(btf_vmlinux, ctx_struct->name_off);
	if (!ctx_tname) {
		/* should not happen */
		bpf_log(log, "Please fix kernel include/linux/bpf_types.h\n");
		return NULL;
	}
	/* only compare that prog's ctx type name is the same as
	 * kernel expects. No need to compare field by field.
	 * It's ok for bpf prog to do:
	 * struct __sk_buff {};
	 * int socket_filter_bpf_prog(struct __sk_buff *skb)
	 * { // no fields of skb are ever used }
	 */
	if (strcmp(ctx_tname, tname))
		return NULL;
	return ctx_type;
}

static int btf_translate_to_vmlinux(struct bpf_verifier_log *log,
				     struct btf *btf,
				     const struct btf_type *t,
				     enum bpf_prog_type prog_type)
{
	const struct btf_member *prog_ctx_type, *kern_ctx_type;

	prog_ctx_type = btf_get_prog_ctx_type(log, btf, t, prog_type);
	if (!prog_ctx_type)
		return -ENOENT;
	kern_ctx_type = prog_ctx_type + 1;
	return kern_ctx_type->type;
}

struct btf *btf_parse_vmlinux(void)
{
	struct btf_verifier_env *env = NULL;
	struct bpf_verifier_log *log;
	struct btf *btf = NULL;
	int err, i;

	env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
	if (!env)
		return ERR_PTR(-ENOMEM);

	log = &env->log;
	log->level = BPF_LOG_KERNEL;

	btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
	if (!btf) {
		err = -ENOMEM;
		goto errout;
	}
	env->btf = btf;

	btf->data = _binary__btf_vmlinux_bin_start;
	btf->data_size = _binary__btf_vmlinux_bin_end -
		_binary__btf_vmlinux_bin_start;

	err = btf_parse_hdr(env);
	if (err)
		goto errout;

	btf->nohdr_data = btf->data + btf->hdr.hdr_len;

	err = btf_parse_str_sec(env);
	if (err)
		goto errout;

	err = btf_check_all_metas(env);
	if (err)
		goto errout;

	/* find struct bpf_ctx_convert for type checking later */
	for (i = 1; i <= btf->nr_types; i++) {
		const struct btf_type *t;
		const char *tname;

		t = btf_type_by_id(btf, i);
		if (!__btf_type_is_struct(t))
			continue;
		tname = __btf_name_by_offset(btf, t->name_off);
		if (!strcmp(tname, "bpf_ctx_convert")) {
			/* btf_parse_vmlinux() runs under bpf_verifier_lock */
			bpf_ctx_convert.t = t;
			break;
		}
	}
	if (i > btf->nr_types) {
		err = -ENOENT;
		goto errout;
	}

	btf_verifier_env_free(env);
	refcount_set(&btf->refcnt, 1);
	return btf;

errout:
	btf_verifier_env_free(env);
	if (btf) {
		kvfree(btf->types);
		kfree(btf);
	}
	return ERR_PTR(err);
}

struct btf *bpf_prog_get_target_btf(const struct bpf_prog *prog)
{
	struct bpf_prog *tgt_prog = prog->aux->linked_prog;

	if (tgt_prog) {
		return tgt_prog->aux->btf;
	} else {
		return btf_vmlinux;
	}
}

bool btf_ctx_access(int off, int size, enum bpf_access_type type,
		    const struct bpf_prog *prog,
		    struct bpf_insn_access_aux *info)
{
	const struct btf_type *t = prog->aux->attach_func_proto;
	struct bpf_prog *tgt_prog = prog->aux->linked_prog;
	struct btf *btf = bpf_prog_get_target_btf(prog);
	const char *tname = prog->aux->attach_func_name;
	struct bpf_verifier_log *log = info->log;
	const struct btf_param *args;
	u32 nr_args, arg;
	int ret;

	if (off % 8) {
		bpf_log(log, "func '%s' offset %d is not multiple of 8\n",
			tname, off);
		return false;
	}
	arg = off / 8;
	args = (const struct btf_param *)(t + 1);
	/* if (t == NULL) Fall back to default BPF prog with 5 u64 arguments */
	nr_args = t ? btf_type_vlen(t) : 5;
	if (prog->aux->attach_btf_trace) {
		/* skip first 'void *__data' argument in btf_trace_##name typedef */
		args++;
		nr_args--;
	}

	if (prog->expected_attach_type == BPF_TRACE_FEXIT &&
	    arg == nr_args) {
		if (!t)
			/* Default prog with 5 args. 6th arg is retval. */
			return true;
		/* function return type */
		t = btf_type_by_id(btf, t->type);
	} else if (arg >= nr_args) {
		bpf_log(log, "func '%s' doesn't have %d-th argument\n",
			tname, arg + 1);
		return false;
	} else {
		if (!t)
			/* Default prog with 5 args */
			return true;
		t = btf_type_by_id(btf, args[arg].type);
	}
	/* skip modifiers */
	while (btf_type_is_modifier(t))
		t = btf_type_by_id(btf, t->type);
	if (btf_type_is_int(t))
		/* accessing a scalar */
		return true;
	if (!btf_type_is_ptr(t)) {
		bpf_log(log,
			"func '%s' arg%d '%s' has type %s. Only pointer access is allowed\n",
			tname, arg,
			__btf_name_by_offset(btf, t->name_off),
			btf_kind_str[BTF_INFO_KIND(t->info)]);
		return false;
	}
	if (t->type == 0)
		/* This is a pointer to void.
		 * It is the same as scalar from the verifier safety pov.
		 * No further pointer walking is allowed.
		 */
		return true;

	/* this is a pointer to another type */
	info->reg_type = PTR_TO_BTF_ID;
	info->btf_id = t->type;

	if (tgt_prog) {
		ret = btf_translate_to_vmlinux(log, btf, t, tgt_prog->type);
		if (ret > 0) {
			info->btf_id = ret;
			return true;
		} else {
			return false;
		}
	}
	t = btf_type_by_id(btf, t->type);
	/* skip modifiers */
	while (btf_type_is_modifier(t))
		t = btf_type_by_id(btf, t->type);
	if (!btf_type_is_struct(t)) {
		bpf_log(log,
			"func '%s' arg%d type %s is not a struct\n",
			tname, arg, btf_kind_str[BTF_INFO_KIND(t->info)]);
		return false;
	}
	bpf_log(log, "func '%s' arg%d has btf_id %d type %s '%s'\n",
		tname, arg, info->btf_id, btf_kind_str[BTF_INFO_KIND(t->info)],
		__btf_name_by_offset(btf, t->name_off));
	return true;
}

int btf_struct_access(struct bpf_verifier_log *log,
		      const struct btf_type *t, int off, int size,
		      enum bpf_access_type atype,
		      u32 *next_btf_id)
{
	u32 i, moff, mtrue_end, msize = 0, total_nelems = 0;
	const struct btf_type *mtype, *elem_type = NULL;
	const struct btf_member *member;
	const char *tname, *mname;

again:
	tname = __btf_name_by_offset(btf_vmlinux, t->name_off);
	if (!btf_type_is_struct(t)) {
		bpf_log(log, "Type '%s' is not a struct", tname);
		return -EINVAL;
	}

	for_each_member(i, t, member) {
		if (btf_member_bitfield_size(t, member))
			/* bitfields are not supported yet */
			continue;

		/* offset of the field in bytes */
		moff = btf_member_bit_offset(t, member) / 8;
		if (off + size <= moff)
			/* won't find anything, field is already too far */
			break;
		/* In case of "off" is pointing to holes of a struct */
		if (off < moff)
			continue;

		/* type of the field */
		mtype = btf_type_by_id(btf_vmlinux, member->type);
		mname = __btf_name_by_offset(btf_vmlinux, member->name_off);

		mtype = btf_resolve_size(btf_vmlinux, mtype, &msize,
					 &elem_type, &total_nelems);
		if (IS_ERR(mtype)) {
			bpf_log(log, "field %s doesn't have size\n", mname);
			return -EFAULT;
		}

		mtrue_end = moff + msize;
		if (off >= mtrue_end)
			/* no overlap with member, keep iterating */
			continue;

		if (btf_type_is_array(mtype)) {
			u32 elem_idx;

			/* btf_resolve_size() above helps to
			 * linearize a multi-dimensional array.
			 *
			 * The logic here is treating an array
			 * in a struct as the following way:
			 *
			 * struct outer {
			 *	struct inner array[2][2];
			 * };
			 *
			 * looks like:
			 *
			 * struct outer {
			 *	struct inner array_elem0;
			 *	struct inner array_elem1;
			 *	struct inner array_elem2;
			 *	struct inner array_elem3;
			 * };
			 *
			 * When accessing outer->array[1][0], it moves
			 * moff to "array_elem2", set mtype to
			 * "struct inner", and msize also becomes
			 * sizeof(struct inner).  Then most of the
			 * remaining logic will fall through without
			 * caring the current member is an array or
			 * not.
			 *
			 * Unlike mtype/msize/moff, mtrue_end does not
			 * change.  The naming difference ("_true") tells
			 * that it is not always corresponding to
			 * the current mtype/msize/moff.
			 * It is the true end of the current
			 * member (i.e. array in this case).  That
			 * will allow an int array to be accessed like
			 * a scratch space,
			 * i.e. allow access beyond the size of
			 *      the array's element as long as it is
			 *      within the mtrue_end boundary.
			 */

			/* skip empty array */
			if (moff == mtrue_end)
				continue;

			msize /= total_nelems;
			elem_idx = (off - moff) / msize;
			moff += elem_idx * msize;
			mtype = elem_type;
		}

		/* the 'off' we're looking for is either equal to start
		 * of this field or inside of this struct
		 */
		if (btf_type_is_struct(mtype)) {
			/* our field must be inside that union or struct */
			t = mtype;

			/* adjust offset we're looking for */
			off -= moff;
			goto again;
		}

		if (btf_type_is_ptr(mtype)) {
			const struct btf_type *stype;

			if (msize != size || off != moff) {
				bpf_log(log,
					"cannot access ptr member %s with moff %u in struct %s with off %u size %u\n",
					mname, moff, tname, off, size);
				return -EACCES;
			}

			stype = btf_type_by_id(btf_vmlinux, mtype->type);
			/* skip modifiers */
			while (btf_type_is_modifier(stype))
				stype = btf_type_by_id(btf_vmlinux, stype->type);
			if (btf_type_is_struct(stype)) {
				*next_btf_id = mtype->type;
				return PTR_TO_BTF_ID;
			}
		}

		/* Allow more flexible access within an int as long as
		 * it is within mtrue_end.
		 * Since mtrue_end could be the end of an array,
		 * that also allows using an array of int as a scratch
		 * space. e.g. skb->cb[].
		 */
		if (off + size > mtrue_end) {
			bpf_log(log,
				"access beyond the end of member %s (mend:%u) in struct %s with off %u size %u\n",
				mname, mtrue_end, tname, off, size);
			return -EACCES;
		}

		return SCALAR_VALUE;
	}
	bpf_log(log, "struct %s doesn't have field at offset %d\n", tname, off);
	return -EINVAL;
}

static int __btf_resolve_helper_id(struct bpf_verifier_log *log, void *fn,
				   int arg)
{
	char fnname[KSYM_SYMBOL_LEN + 4] = "btf_";
	const struct btf_param *args;
	const struct btf_type *t;
	const char *tname, *sym;
	u32 btf_id, i;

	if (IS_ERR(btf_vmlinux)) {
		bpf_log(log, "btf_vmlinux is malformed\n");
		return -EINVAL;
	}

	sym = kallsyms_lookup((long)fn, NULL, NULL, NULL, fnname + 4);
	if (!sym) {
		bpf_log(log, "kernel doesn't have kallsyms\n");
		return -EFAULT;
	}

	for (i = 1; i <= btf_vmlinux->nr_types; i++) {
		t = btf_type_by_id(btf_vmlinux, i);
		if (BTF_INFO_KIND(t->info) != BTF_KIND_TYPEDEF)
			continue;
		tname = __btf_name_by_offset(btf_vmlinux, t->name_off);
		if (!strcmp(tname, fnname))
			break;
	}
	if (i > btf_vmlinux->nr_types) {
		bpf_log(log, "helper %s type is not found\n", fnname);
		return -ENOENT;
	}

	t = btf_type_by_id(btf_vmlinux, t->type);
	if (!btf_type_is_ptr(t))
		return -EFAULT;
	t = btf_type_by_id(btf_vmlinux, t->type);
	if (!btf_type_is_func_proto(t))
		return -EFAULT;

	args = (const struct btf_param *)(t + 1);
	if (arg >= btf_type_vlen(t)) {
		bpf_log(log, "bpf helper %s doesn't have %d-th argument\n",
			fnname, arg);
		return -EINVAL;
	}

	t = btf_type_by_id(btf_vmlinux, args[arg].type);
	if (!btf_type_is_ptr(t) || !t->type) {
		/* anything but the pointer to struct is a helper config bug */
		bpf_log(log, "ARG_PTR_TO_BTF is misconfigured\n");
		return -EFAULT;
	}
	btf_id = t->type;
	t = btf_type_by_id(btf_vmlinux, t->type);
	/* skip modifiers */
	while (btf_type_is_modifier(t)) {
		btf_id = t->type;
		t = btf_type_by_id(btf_vmlinux, t->type);
	}
	if (!btf_type_is_struct(t)) {
		bpf_log(log, "ARG_PTR_TO_BTF is not a struct\n");
		return -EFAULT;
	}
	bpf_log(log, "helper %s arg%d has btf_id %d struct %s\n", fnname + 4,
		arg, btf_id, __btf_name_by_offset(btf_vmlinux, t->name_off));
	return btf_id;
}

int btf_resolve_helper_id(struct bpf_verifier_log *log,
			  const struct bpf_func_proto *fn, int arg)
{
	int *btf_id = &fn->btf_id[arg];
	int ret;

	if (fn->arg_type[arg] != ARG_PTR_TO_BTF_ID)
		return -EINVAL;

	ret = READ_ONCE(*btf_id);
	if (ret)
		return ret;
	/* ok to race the search. The result is the same */
	ret = __btf_resolve_helper_id(log, fn->func, arg);
	if (!ret) {
		/* Function argument cannot be type 'void' */
		bpf_log(log, "BTF resolution bug\n");
		return -EFAULT;
	}
	WRITE_ONCE(*btf_id, ret);
	return ret;
}

static int __get_type_size(struct btf *btf, u32 btf_id,
			   const struct btf_type **bad_type)
{
	const struct btf_type *t;

	if (!btf_id)
		/* void */
		return 0;
	t = btf_type_by_id(btf, btf_id);
	while (t && btf_type_is_modifier(t))
		t = btf_type_by_id(btf, t->type);
	if (!t) {
		*bad_type = btf->types[0];
		return -EINVAL;
	}
	if (btf_type_is_ptr(t))
		/* kernel size of pointer. Not BPF's size of pointer*/
		return sizeof(void *);
	if (btf_type_is_int(t) || btf_type_is_enum(t))
		return t->size;
	*bad_type = t;
	return -EINVAL;
}

int btf_distill_func_proto(struct bpf_verifier_log *log,
			   struct btf *btf,
			   const struct btf_type *func,
			   const char *tname,
			   struct btf_func_model *m)
{
	const struct btf_param *args;
	const struct btf_type *t;
	u32 i, nargs;
	int ret;

	if (!func) {
		/* BTF function prototype doesn't match the verifier types.
		 * Fall back to 5 u64 args.
		 */
		for (i = 0; i < 5; i++)
			m->arg_size[i] = 8;
		m->ret_size = 8;
		m->nr_args = 5;
		return 0;
	}
	args = (const struct btf_param *)(func + 1);
	nargs = btf_type_vlen(func);
	if (nargs >= MAX_BPF_FUNC_ARGS) {
		bpf_log(log,
			"The function %s has %d arguments. Too many.\n",
			tname, nargs);
		return -EINVAL;
	}
	ret = __get_type_size(btf, func->type, &t);
	if (ret < 0) {
		bpf_log(log,
			"The function %s return type %s is unsupported.\n",
			tname, btf_kind_str[BTF_INFO_KIND(t->info)]);
		return -EINVAL;
	}
	m->ret_size = ret;

	for (i = 0; i < nargs; i++) {
		ret = __get_type_size(btf, args[i].type, &t);
		if (ret < 0) {
			bpf_log(log,
				"The function %s arg%d type %s is unsupported.\n",
				tname, i, btf_kind_str[BTF_INFO_KIND(t->info)]);
			return -EINVAL;
		}
		m->arg_size[i] = ret;
	}
	m->nr_args = nargs;
	return 0;
}

int btf_check_func_arg_match(struct bpf_verifier_env *env, int subprog)
{
	struct bpf_verifier_state *st = env->cur_state;
	struct bpf_func_state *func = st->frame[st->curframe];
	struct bpf_reg_state *reg = func->regs;
	struct bpf_verifier_log *log = &env->log;
	struct bpf_prog *prog = env->prog;
	struct btf *btf = prog->aux->btf;
	const struct btf_param *args;
	const struct btf_type *t;
	u32 i, nargs, btf_id;
	const char *tname;

	if (!prog->aux->func_info)
		return 0;

	btf_id = prog->aux->func_info[subprog].type_id;
	if (!btf_id)
		return 0;

	if (prog->aux->func_info_aux[subprog].unreliable)
		return 0;

	t = btf_type_by_id(btf, btf_id);
	if (!t || !btf_type_is_func(t)) {
		bpf_log(log, "BTF of subprog %d doesn't point to KIND_FUNC\n",
			subprog);
		return -EINVAL;
	}
	tname = btf_name_by_offset(btf, t->name_off);

	t = btf_type_by_id(btf, t->type);
	if (!t || !btf_type_is_func_proto(t)) {
		bpf_log(log, "Invalid type of func %s\n", tname);
		return -EINVAL;
	}
	args = (const struct btf_param *)(t + 1);
	nargs = btf_type_vlen(t);
	if (nargs > 5) {
		bpf_log(log, "Function %s has %d > 5 args\n", tname, nargs);
		goto out;
	}
	/* check that BTF function arguments match actual types that the
	 * verifier sees.
	 */
	for (i = 0; i < nargs; i++) {
		t = btf_type_by_id(btf, args[i].type);
		while (btf_type_is_modifier(t))
			t = btf_type_by_id(btf, t->type);
		if (btf_type_is_int(t) || btf_type_is_enum(t)) {
			if (reg[i + 1].type == SCALAR_VALUE)
				continue;
			bpf_log(log, "R%d is not a scalar\n", i + 1);
			goto out;
		}
		if (btf_type_is_ptr(t)) {
			if (reg[i + 1].type == SCALAR_VALUE) {
				bpf_log(log, "R%d is not a pointer\n", i + 1);
				goto out;
			}
			/* If program is passing PTR_TO_CTX into subprogram
			 * check that BTF type matches.
			 */
			if (reg[i + 1].type == PTR_TO_CTX &&
			    !btf_get_prog_ctx_type(log, btf, t, prog->type))
				goto out;
			/* All other pointers are ok */
			continue;
		}
		bpf_log(log, "Unrecognized argument type %s\n",
			btf_kind_str[BTF_INFO_KIND(t->info)]);
		goto out;
	}
	return 0;
out:
	/* LLVM optimizations can remove arguments from static functions. */
	bpf_log(log,
		"Type info disagrees with actual arguments due to compiler optimizations\n");
	prog->aux->func_info_aux[subprog].unreliable = true;
	return 0;
}

void btf_type_seq_show(const struct btf *btf, u32 type_id, void *obj,
		       struct seq_file *m)
{
	const struct btf_type *t = btf_type_by_id(btf, type_id);

	btf_type_ops(t)->seq_show(btf, t, type_id, obj, 0, m);
}

#ifdef CONFIG_PROC_FS
static void bpf_btf_show_fdinfo(struct seq_file *m, struct file *filp)
{
	const struct btf *btf = filp->private_data;

	seq_printf(m, "btf_id:\t%u\n", btf->id);
}
#endif

static int btf_release(struct inode *inode, struct file *filp)
{
	btf_put(filp->private_data);
	return 0;
}

const struct file_operations btf_fops = {
#ifdef CONFIG_PROC_FS
	.show_fdinfo	= bpf_btf_show_fdinfo,
#endif
	.release	= btf_release,
};

static int __btf_new_fd(struct btf *btf)
{
	return anon_inode_getfd("btf", &btf_fops, btf, O_RDONLY | O_CLOEXEC);
}

int btf_new_fd(const union bpf_attr *attr)
{
	struct btf *btf;
	int ret;

	btf = btf_parse(u64_to_user_ptr(attr->btf),
			attr->btf_size, attr->btf_log_level,
			u64_to_user_ptr(attr->btf_log_buf),
			attr->btf_log_size);
	if (IS_ERR(btf))
		return PTR_ERR(btf);

	ret = btf_alloc_id(btf);
	if (ret) {
		btf_free(btf);
		return ret;
	}

	/*
	 * The BTF ID is published to the userspace.
	 * All BTF free must go through call_rcu() from
	 * now on (i.e. free by calling btf_put()).
	 */

	ret = __btf_new_fd(btf);
	if (ret < 0)
		btf_put(btf);

	return ret;
}

struct btf *btf_get_by_fd(int fd)
{
	struct btf *btf;
	struct fd f;

	f = fdget(fd);

	if (!f.file)
		return ERR_PTR(-EBADF);

	if (f.file->f_op != &btf_fops) {
		fdput(f);
		return ERR_PTR(-EINVAL);
	}

	btf = f.file->private_data;
	refcount_inc(&btf->refcnt);
	fdput(f);

	return btf;
}

int btf_get_info_by_fd(const struct btf *btf,
		       const union bpf_attr *attr,
		       union bpf_attr __user *uattr)
{
	struct bpf_btf_info __user *uinfo;
	struct bpf_btf_info info = {};
	u32 info_copy, btf_copy;
	void __user *ubtf;
	u32 uinfo_len;

	uinfo = u64_to_user_ptr(attr->info.info);
	uinfo_len = attr->info.info_len;

	info_copy = min_t(u32, uinfo_len, sizeof(info));
	if (copy_from_user(&info, uinfo, info_copy))
		return -EFAULT;

	info.id = btf->id;
	ubtf = u64_to_user_ptr(info.btf);
	btf_copy = min_t(u32, btf->data_size, info.btf_size);
	if (copy_to_user(ubtf, btf->data, btf_copy))
		return -EFAULT;
	info.btf_size = btf->data_size;

	if (copy_to_user(uinfo, &info, info_copy) ||
	    put_user(info_copy, &uattr->info.info_len))
		return -EFAULT;

	return 0;
}

int btf_get_fd_by_id(u32 id)
{
	struct btf *btf;
	int fd;

	rcu_read_lock();
	btf = idr_find(&btf_idr, id);
	if (!btf || !refcount_inc_not_zero(&btf->refcnt))
		btf = ERR_PTR(-ENOENT);
	rcu_read_unlock();

	if (IS_ERR(btf))
		return PTR_ERR(btf);

	fd = __btf_new_fd(btf);
	if (fd < 0)
		btf_put(btf);

	return fd;
}

u32 btf_id(const struct btf *btf)
{
	return btf->id;
}