summaryrefslogtreecommitdiff
path: root/arch/arm64/mm/mmu.c
blob: add67deb491080d3de30785b478a0ceca8ce79f3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Based on arch/arm/mm/mmu.c
 *
 * Copyright (C) 1995-2005 Russell King
 * Copyright (C) 2012 ARM Ltd.
 */

#include <linux/cache.h>
#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/kexec.h>
#include <linux/libfdt.h>
#include <linux/mman.h>
#include <linux/nodemask.h>
#include <linux/memblock.h>
#include <linux/memory.h>
#include <linux/fs.h>
#include <linux/io.h>
#include <linux/mm.h>
#include <linux/vmalloc.h>

#include <asm/barrier.h>
#include <asm/cputype.h>
#include <asm/fixmap.h>
#include <asm/kasan.h>
#include <asm/kernel-pgtable.h>
#include <asm/sections.h>
#include <asm/setup.h>
#include <linux/sizes.h>
#include <asm/tlb.h>
#include <asm/mmu_context.h>
#include <asm/ptdump.h>
#include <asm/tlbflush.h>
#include <asm/pgalloc.h>

#define NO_BLOCK_MAPPINGS	BIT(0)
#define NO_CONT_MAPPINGS	BIT(1)
#define NO_EXEC_MAPPINGS	BIT(2)	/* assumes FEAT_HPDS is not used */

u64 idmap_t0sz = TCR_T0SZ(VA_BITS_MIN);
u64 idmap_ptrs_per_pgd = PTRS_PER_PGD;

u64 __section(".mmuoff.data.write") vabits_actual;
EXPORT_SYMBOL(vabits_actual);

u64 kimage_voffset __ro_after_init;
EXPORT_SYMBOL(kimage_voffset);

/*
 * Empty_zero_page is a special page that is used for zero-initialized data
 * and COW.
 */
unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss;
EXPORT_SYMBOL(empty_zero_page);

static pte_t bm_pte[PTRS_PER_PTE] __page_aligned_bss;
static pmd_t bm_pmd[PTRS_PER_PMD] __page_aligned_bss __maybe_unused;
static pud_t bm_pud[PTRS_PER_PUD] __page_aligned_bss __maybe_unused;

static DEFINE_SPINLOCK(swapper_pgdir_lock);

void set_swapper_pgd(pgd_t *pgdp, pgd_t pgd)
{
	pgd_t *fixmap_pgdp;

	spin_lock(&swapper_pgdir_lock);
	fixmap_pgdp = pgd_set_fixmap(__pa_symbol(pgdp));
	WRITE_ONCE(*fixmap_pgdp, pgd);
	/*
	 * We need dsb(ishst) here to ensure the page-table-walker sees
	 * our new entry before set_p?d() returns. The fixmap's
	 * flush_tlb_kernel_range() via clear_fixmap() does this for us.
	 */
	pgd_clear_fixmap();
	spin_unlock(&swapper_pgdir_lock);
}

pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
			      unsigned long size, pgprot_t vma_prot)
{
	if (!pfn_valid(pfn))
		return pgprot_noncached(vma_prot);
	else if (file->f_flags & O_SYNC)
		return pgprot_writecombine(vma_prot);
	return vma_prot;
}
EXPORT_SYMBOL(phys_mem_access_prot);

static phys_addr_t __init early_pgtable_alloc(int shift)
{
	phys_addr_t phys;
	void *ptr;

	phys = memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE);
	if (!phys)
		panic("Failed to allocate page table page\n");

	/*
	 * The FIX_{PGD,PUD,PMD} slots may be in active use, but the FIX_PTE
	 * slot will be free, so we can (ab)use the FIX_PTE slot to initialise
	 * any level of table.
	 */
	ptr = pte_set_fixmap(phys);

	memset(ptr, 0, PAGE_SIZE);

	/*
	 * Implicit barriers also ensure the zeroed page is visible to the page
	 * table walker
	 */
	pte_clear_fixmap();

	return phys;
}

static bool pgattr_change_is_safe(u64 old, u64 new)
{
	/*
	 * The following mapping attributes may be updated in live
	 * kernel mappings without the need for break-before-make.
	 */
	pteval_t mask = PTE_PXN | PTE_RDONLY | PTE_WRITE | PTE_NG;

	/* creating or taking down mappings is always safe */
	if (old == 0 || new == 0)
		return true;

	/* live contiguous mappings may not be manipulated at all */
	if ((old | new) & PTE_CONT)
		return false;

	/* Transitioning from Non-Global to Global is unsafe */
	if (old & ~new & PTE_NG)
		return false;

	/*
	 * Changing the memory type between Normal and Normal-Tagged is safe
	 * since Tagged is considered a permission attribute from the
	 * mismatched attribute aliases perspective.
	 */
	if (((old & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL) ||
	     (old & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL_TAGGED)) &&
	    ((new & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL) ||
	     (new & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL_TAGGED)))
		mask |= PTE_ATTRINDX_MASK;

	return ((old ^ new) & ~mask) == 0;
}

static void init_pte(pmd_t *pmdp, unsigned long addr, unsigned long end,
		     phys_addr_t phys, pgprot_t prot)
{
	pte_t *ptep;

	ptep = pte_set_fixmap_offset(pmdp, addr);
	do {
		pte_t old_pte = READ_ONCE(*ptep);

		set_pte(ptep, pfn_pte(__phys_to_pfn(phys), prot));

		/*
		 * After the PTE entry has been populated once, we
		 * only allow updates to the permission attributes.
		 */
		BUG_ON(!pgattr_change_is_safe(pte_val(old_pte),
					      READ_ONCE(pte_val(*ptep))));

		phys += PAGE_SIZE;
	} while (ptep++, addr += PAGE_SIZE, addr != end);

	pte_clear_fixmap();
}

static void alloc_init_cont_pte(pmd_t *pmdp, unsigned long addr,
				unsigned long end, phys_addr_t phys,
				pgprot_t prot,
				phys_addr_t (*pgtable_alloc)(int),
				int flags)
{
	unsigned long next;
	pmd_t pmd = READ_ONCE(*pmdp);

	BUG_ON(pmd_sect(pmd));
	if (pmd_none(pmd)) {
		pmdval_t pmdval = PMD_TYPE_TABLE | PMD_TABLE_UXN;
		phys_addr_t pte_phys;

		if (flags & NO_EXEC_MAPPINGS)
			pmdval |= PMD_TABLE_PXN;
		BUG_ON(!pgtable_alloc);
		pte_phys = pgtable_alloc(PAGE_SHIFT);
		__pmd_populate(pmdp, pte_phys, pmdval);
		pmd = READ_ONCE(*pmdp);
	}
	BUG_ON(pmd_bad(pmd));

	do {
		pgprot_t __prot = prot;

		next = pte_cont_addr_end(addr, end);

		/* use a contiguous mapping if the range is suitably aligned */
		if ((((addr | next | phys) & ~CONT_PTE_MASK) == 0) &&
		    (flags & NO_CONT_MAPPINGS) == 0)
			__prot = __pgprot(pgprot_val(prot) | PTE_CONT);

		init_pte(pmdp, addr, next, phys, __prot);

		phys += next - addr;
	} while (addr = next, addr != end);
}

static void init_pmd(pud_t *pudp, unsigned long addr, unsigned long end,
		     phys_addr_t phys, pgprot_t prot,
		     phys_addr_t (*pgtable_alloc)(int), int flags)
{
	unsigned long next;
	pmd_t *pmdp;

	pmdp = pmd_set_fixmap_offset(pudp, addr);
	do {
		pmd_t old_pmd = READ_ONCE(*pmdp);

		next = pmd_addr_end(addr, end);

		/* try section mapping first */
		if (((addr | next | phys) & ~SECTION_MASK) == 0 &&
		    (flags & NO_BLOCK_MAPPINGS) == 0) {
			pmd_set_huge(pmdp, phys, prot);

			/*
			 * After the PMD entry has been populated once, we
			 * only allow updates to the permission attributes.
			 */
			BUG_ON(!pgattr_change_is_safe(pmd_val(old_pmd),
						      READ_ONCE(pmd_val(*pmdp))));
		} else {
			alloc_init_cont_pte(pmdp, addr, next, phys, prot,
					    pgtable_alloc, flags);

			BUG_ON(pmd_val(old_pmd) != 0 &&
			       pmd_val(old_pmd) != READ_ONCE(pmd_val(*pmdp)));
		}
		phys += next - addr;
	} while (pmdp++, addr = next, addr != end);

	pmd_clear_fixmap();
}

static void alloc_init_cont_pmd(pud_t *pudp, unsigned long addr,
				unsigned long end, phys_addr_t phys,
				pgprot_t prot,
				phys_addr_t (*pgtable_alloc)(int), int flags)
{
	unsigned long next;
	pud_t pud = READ_ONCE(*pudp);

	/*
	 * Check for initial section mappings in the pgd/pud.
	 */
	BUG_ON(pud_sect(pud));
	if (pud_none(pud)) {
		pudval_t pudval = PUD_TYPE_TABLE | PUD_TABLE_UXN;
		phys_addr_t pmd_phys;

		if (flags & NO_EXEC_MAPPINGS)
			pudval |= PUD_TABLE_PXN;
		BUG_ON(!pgtable_alloc);
		pmd_phys = pgtable_alloc(PMD_SHIFT);
		__pud_populate(pudp, pmd_phys, pudval);
		pud = READ_ONCE(*pudp);
	}
	BUG_ON(pud_bad(pud));

	do {
		pgprot_t __prot = prot;

		next = pmd_cont_addr_end(addr, end);

		/* use a contiguous mapping if the range is suitably aligned */
		if ((((addr | next | phys) & ~CONT_PMD_MASK) == 0) &&
		    (flags & NO_CONT_MAPPINGS) == 0)
			__prot = __pgprot(pgprot_val(prot) | PTE_CONT);

		init_pmd(pudp, addr, next, phys, __prot, pgtable_alloc, flags);

		phys += next - addr;
	} while (addr = next, addr != end);
}

static inline bool use_1G_block(unsigned long addr, unsigned long next,
			unsigned long phys)
{
	if (PAGE_SHIFT != 12)
		return false;

	if (((addr | next | phys) & ~PUD_MASK) != 0)
		return false;

	return true;
}

static void alloc_init_pud(pgd_t *pgdp, unsigned long addr, unsigned long end,
			   phys_addr_t phys, pgprot_t prot,
			   phys_addr_t (*pgtable_alloc)(int),
			   int flags)
{
	unsigned long next;
	pud_t *pudp;
	p4d_t *p4dp = p4d_offset(pgdp, addr);
	p4d_t p4d = READ_ONCE(*p4dp);

	if (p4d_none(p4d)) {
		p4dval_t p4dval = P4D_TYPE_TABLE | P4D_TABLE_UXN;
		phys_addr_t pud_phys;

		if (flags & NO_EXEC_MAPPINGS)
			p4dval |= P4D_TABLE_PXN;
		BUG_ON(!pgtable_alloc);
		pud_phys = pgtable_alloc(PUD_SHIFT);
		__p4d_populate(p4dp, pud_phys, p4dval);
		p4d = READ_ONCE(*p4dp);
	}
	BUG_ON(p4d_bad(p4d));

	pudp = pud_set_fixmap_offset(p4dp, addr);
	do {
		pud_t old_pud = READ_ONCE(*pudp);

		next = pud_addr_end(addr, end);

		/*
		 * For 4K granule only, attempt to put down a 1GB block
		 */
		if (use_1G_block(addr, next, phys) &&
		    (flags & NO_BLOCK_MAPPINGS) == 0) {
			pud_set_huge(pudp, phys, prot);

			/*
			 * After the PUD entry has been populated once, we
			 * only allow updates to the permission attributes.
			 */
			BUG_ON(!pgattr_change_is_safe(pud_val(old_pud),
						      READ_ONCE(pud_val(*pudp))));
		} else {
			alloc_init_cont_pmd(pudp, addr, next, phys, prot,
					    pgtable_alloc, flags);

			BUG_ON(pud_val(old_pud) != 0 &&
			       pud_val(old_pud) != READ_ONCE(pud_val(*pudp)));
		}
		phys += next - addr;
	} while (pudp++, addr = next, addr != end);

	pud_clear_fixmap();
}

static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys,
				 unsigned long virt, phys_addr_t size,
				 pgprot_t prot,
				 phys_addr_t (*pgtable_alloc)(int),
				 int flags)
{
	unsigned long addr, end, next;
	pgd_t *pgdp = pgd_offset_pgd(pgdir, virt);

	/*
	 * If the virtual and physical address don't have the same offset
	 * within a page, we cannot map the region as the caller expects.
	 */
	if (WARN_ON((phys ^ virt) & ~PAGE_MASK))
		return;

	phys &= PAGE_MASK;
	addr = virt & PAGE_MASK;
	end = PAGE_ALIGN(virt + size);

	do {
		next = pgd_addr_end(addr, end);
		alloc_init_pud(pgdp, addr, next, phys, prot, pgtable_alloc,
			       flags);
		phys += next - addr;
	} while (pgdp++, addr = next, addr != end);
}

static phys_addr_t __pgd_pgtable_alloc(int shift)
{
	void *ptr = (void *)__get_free_page(GFP_PGTABLE_KERNEL);
	BUG_ON(!ptr);

	/* Ensure the zeroed page is visible to the page table walker */
	dsb(ishst);
	return __pa(ptr);
}

static phys_addr_t pgd_pgtable_alloc(int shift)
{
	phys_addr_t pa = __pgd_pgtable_alloc(shift);

	/*
	 * Call proper page table ctor in case later we need to
	 * call core mm functions like apply_to_page_range() on
	 * this pre-allocated page table.
	 *
	 * We don't select ARCH_ENABLE_SPLIT_PMD_PTLOCK if pmd is
	 * folded, and if so pgtable_pmd_page_ctor() becomes nop.
	 */
	if (shift == PAGE_SHIFT)
		BUG_ON(!pgtable_pte_page_ctor(phys_to_page(pa)));
	else if (shift == PMD_SHIFT)
		BUG_ON(!pgtable_pmd_page_ctor(phys_to_page(pa)));

	return pa;
}

/*
 * This function can only be used to modify existing table entries,
 * without allocating new levels of table. Note that this permits the
 * creation of new section or page entries.
 */
static void __init create_mapping_noalloc(phys_addr_t phys, unsigned long virt,
				  phys_addr_t size, pgprot_t prot)
{
	if ((virt >= PAGE_END) && (virt < VMALLOC_START)) {
		pr_warn("BUG: not creating mapping for %pa at 0x%016lx - outside kernel range\n",
			&phys, virt);
		return;
	}
	__create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL,
			     NO_CONT_MAPPINGS);
}

void __init create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,
			       unsigned long virt, phys_addr_t size,
			       pgprot_t prot, bool page_mappings_only)
{
	int flags = 0;

	BUG_ON(mm == &init_mm);

	if (page_mappings_only)
		flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;

	__create_pgd_mapping(mm->pgd, phys, virt, size, prot,
			     pgd_pgtable_alloc, flags);
}

static void update_mapping_prot(phys_addr_t phys, unsigned long virt,
				phys_addr_t size, pgprot_t prot)
{
	if ((virt >= PAGE_END) && (virt < VMALLOC_START)) {
		pr_warn("BUG: not updating mapping for %pa at 0x%016lx - outside kernel range\n",
			&phys, virt);
		return;
	}

	__create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL,
			     NO_CONT_MAPPINGS);

	/* flush the TLBs after updating live kernel mappings */
	flush_tlb_kernel_range(virt, virt + size);
}

static void __init __map_memblock(pgd_t *pgdp, phys_addr_t start,
				  phys_addr_t end, pgprot_t prot, int flags)
{
	__create_pgd_mapping(pgdp, start, __phys_to_virt(start), end - start,
			     prot, early_pgtable_alloc, flags);
}

void __init mark_linear_text_alias_ro(void)
{
	/*
	 * Remove the write permissions from the linear alias of .text/.rodata
	 */
	update_mapping_prot(__pa_symbol(_stext), (unsigned long)lm_alias(_stext),
			    (unsigned long)__init_begin - (unsigned long)_stext,
			    PAGE_KERNEL_RO);
}

static bool crash_mem_map __initdata;

static int __init enable_crash_mem_map(char *arg)
{
	/*
	 * Proper parameter parsing is done by reserve_crashkernel(). We only
	 * need to know if the linear map has to avoid block mappings so that
	 * the crashkernel reservations can be unmapped later.
	 */
	crash_mem_map = true;

	return 0;
}
early_param("crashkernel", enable_crash_mem_map);

static void __init map_mem(pgd_t *pgdp)
{
	static const u64 direct_map_end = _PAGE_END(VA_BITS_MIN);
	phys_addr_t kernel_start = __pa_symbol(_stext);
	phys_addr_t kernel_end = __pa_symbol(__init_begin);
	phys_addr_t start, end;
	int flags = NO_EXEC_MAPPINGS;
	u64 i;

	/*
	 * Setting hierarchical PXNTable attributes on table entries covering
	 * the linear region is only possible if it is guaranteed that no table
	 * entries at any level are being shared between the linear region and
	 * the vmalloc region. Check whether this is true for the PGD level, in
	 * which case it is guaranteed to be true for all other levels as well.
	 */
	BUILD_BUG_ON(pgd_index(direct_map_end - 1) == pgd_index(direct_map_end));

	if (rodata_full || crash_mem_map || debug_pagealloc_enabled() ||
	    IS_ENABLED(CONFIG_KFENCE))
		flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;

	/*
	 * Take care not to create a writable alias for the
	 * read-only text and rodata sections of the kernel image.
	 * So temporarily mark them as NOMAP to skip mappings in
	 * the following for-loop
	 */
	memblock_mark_nomap(kernel_start, kernel_end - kernel_start);

	/* map all the memory banks */
	for_each_mem_range(i, &start, &end) {
		if (start >= end)
			break;
		/*
		 * The linear map must allow allocation tags reading/writing
		 * if MTE is present. Otherwise, it has the same attributes as
		 * PAGE_KERNEL.
		 */
		__map_memblock(pgdp, start, end, pgprot_tagged(PAGE_KERNEL),
			       flags);
	}

	/*
	 * Map the linear alias of the [_stext, __init_begin) interval
	 * as non-executable now, and remove the write permission in
	 * mark_linear_text_alias_ro() below (which will be called after
	 * alternative patching has completed). This makes the contents
	 * of the region accessible to subsystems such as hibernate,
	 * but protects it from inadvertent modification or execution.
	 * Note that contiguous mappings cannot be remapped in this way,
	 * so we should avoid them here.
	 */
	__map_memblock(pgdp, kernel_start, kernel_end,
		       PAGE_KERNEL, NO_CONT_MAPPINGS);
	memblock_clear_nomap(kernel_start, kernel_end - kernel_start);
}

void mark_rodata_ro(void)
{
	unsigned long section_size;

	/*
	 * mark .rodata as read only. Use __init_begin rather than __end_rodata
	 * to cover NOTES and EXCEPTION_TABLE.
	 */
	section_size = (unsigned long)__init_begin - (unsigned long)__start_rodata;
	update_mapping_prot(__pa_symbol(__start_rodata), (unsigned long)__start_rodata,
			    section_size, PAGE_KERNEL_RO);

	debug_checkwx();
}

static void __init map_kernel_segment(pgd_t *pgdp, void *va_start, void *va_end,
				      pgprot_t prot, struct vm_struct *vma,
				      int flags, unsigned long vm_flags)
{
	phys_addr_t pa_start = __pa_symbol(va_start);
	unsigned long size = va_end - va_start;

	BUG_ON(!PAGE_ALIGNED(pa_start));
	BUG_ON(!PAGE_ALIGNED(size));

	__create_pgd_mapping(pgdp, pa_start, (unsigned long)va_start, size, prot,
			     early_pgtable_alloc, flags);

	if (!(vm_flags & VM_NO_GUARD))
		size += PAGE_SIZE;

	vma->addr	= va_start;
	vma->phys_addr	= pa_start;
	vma->size	= size;
	vma->flags	= VM_MAP | vm_flags;
	vma->caller	= __builtin_return_address(0);

	vm_area_add_early(vma);
}

static int __init parse_rodata(char *arg)
{
	int ret = strtobool(arg, &rodata_enabled);
	if (!ret) {
		rodata_full = false;
		return 0;
	}

	/* permit 'full' in addition to boolean options */
	if (strcmp(arg, "full"))
		return -EINVAL;

	rodata_enabled = true;
	rodata_full = true;
	return 0;
}
early_param("rodata", parse_rodata);

#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
static int __init map_entry_trampoline(void)
{
	pgprot_t prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC;
	phys_addr_t pa_start = __pa_symbol(__entry_tramp_text_start);

	/* The trampoline is always mapped and can therefore be global */
	pgprot_val(prot) &= ~PTE_NG;

	/* Map only the text into the trampoline page table */
	memset(tramp_pg_dir, 0, PGD_SIZE);
	__create_pgd_mapping(tramp_pg_dir, pa_start, TRAMP_VALIAS, PAGE_SIZE,
			     prot, __pgd_pgtable_alloc, 0);

	/* Map both the text and data into the kernel page table */
	__set_fixmap(FIX_ENTRY_TRAMP_TEXT, pa_start, prot);
	if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {
		extern char __entry_tramp_data_start[];

		__set_fixmap(FIX_ENTRY_TRAMP_DATA,
			     __pa_symbol(__entry_tramp_data_start),
			     PAGE_KERNEL_RO);
	}

	return 0;
}
core_initcall(map_entry_trampoline);
#endif

/*
 * Open coded check for BTI, only for use to determine configuration
 * for early mappings for before the cpufeature code has run.
 */
static bool arm64_early_this_cpu_has_bti(void)
{
	u64 pfr1;

	if (!IS_ENABLED(CONFIG_ARM64_BTI_KERNEL))
		return false;

	pfr1 = __read_sysreg_by_encoding(SYS_ID_AA64PFR1_EL1);
	return cpuid_feature_extract_unsigned_field(pfr1,
						    ID_AA64PFR1_BT_SHIFT);
}

/*
 * Create fine-grained mappings for the kernel.
 */
static void __init map_kernel(pgd_t *pgdp)
{
	static struct vm_struct vmlinux_text, vmlinux_rodata, vmlinux_inittext,
				vmlinux_initdata, vmlinux_data;

	/*
	 * External debuggers may need to write directly to the text
	 * mapping to install SW breakpoints. Allow this (only) when
	 * explicitly requested with rodata=off.
	 */
	pgprot_t text_prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC;

	/*
	 * If we have a CPU that supports BTI and a kernel built for
	 * BTI then mark the kernel executable text as guarded pages
	 * now so we don't have to rewrite the page tables later.
	 */
	if (arm64_early_this_cpu_has_bti())
		text_prot = __pgprot_modify(text_prot, PTE_GP, PTE_GP);

	/*
	 * Only rodata will be remapped with different permissions later on,
	 * all other segments are allowed to use contiguous mappings.
	 */
	map_kernel_segment(pgdp, _stext, _etext, text_prot, &vmlinux_text, 0,
			   VM_NO_GUARD);
	map_kernel_segment(pgdp, __start_rodata, __inittext_begin, PAGE_KERNEL,
			   &vmlinux_rodata, NO_CONT_MAPPINGS, VM_NO_GUARD);
	map_kernel_segment(pgdp, __inittext_begin, __inittext_end, text_prot,
			   &vmlinux_inittext, 0, VM_NO_GUARD);
	map_kernel_segment(pgdp, __initdata_begin, __initdata_end, PAGE_KERNEL,
			   &vmlinux_initdata, 0, VM_NO_GUARD);
	map_kernel_segment(pgdp, _data, _end, PAGE_KERNEL, &vmlinux_data, 0, 0);

	if (!READ_ONCE(pgd_val(*pgd_offset_pgd(pgdp, FIXADDR_START)))) {
		/*
		 * The fixmap falls in a separate pgd to the kernel, and doesn't
		 * live in the carveout for the swapper_pg_dir. We can simply
		 * re-use the existing dir for the fixmap.
		 */
		set_pgd(pgd_offset_pgd(pgdp, FIXADDR_START),
			READ_ONCE(*pgd_offset_k(FIXADDR_START)));
	} else if (CONFIG_PGTABLE_LEVELS > 3) {
		pgd_t *bm_pgdp;
		p4d_t *bm_p4dp;
		pud_t *bm_pudp;
		/*
		 * The fixmap shares its top level pgd entry with the kernel
		 * mapping. This can really only occur when we are running
		 * with 16k/4 levels, so we can simply reuse the pud level
		 * entry instead.
		 */
		BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES));
		bm_pgdp = pgd_offset_pgd(pgdp, FIXADDR_START);
		bm_p4dp = p4d_offset(bm_pgdp, FIXADDR_START);
		bm_pudp = pud_set_fixmap_offset(bm_p4dp, FIXADDR_START);
		pud_populate(&init_mm, bm_pudp, lm_alias(bm_pmd));
		pud_clear_fixmap();
	} else {
		BUG();
	}

	kasan_copy_shadow(pgdp);
}

void __init paging_init(void)
{
	pgd_t *pgdp = pgd_set_fixmap(__pa_symbol(swapper_pg_dir));

	map_kernel(pgdp);
	map_mem(pgdp);

	pgd_clear_fixmap();

	cpu_replace_ttbr1(lm_alias(swapper_pg_dir));
	init_mm.pgd = swapper_pg_dir;

	memblock_free(__pa_symbol(init_pg_dir),
		      __pa_symbol(init_pg_end) - __pa_symbol(init_pg_dir));

	memblock_allow_resize();
}

/*
 * Check whether a kernel address is valid (derived from arch/x86/).
 */
int kern_addr_valid(unsigned long addr)
{
	pgd_t *pgdp;
	p4d_t *p4dp;
	pud_t *pudp, pud;
	pmd_t *pmdp, pmd;
	pte_t *ptep, pte;

	addr = arch_kasan_reset_tag(addr);
	if ((((long)addr) >> VA_BITS) != -1UL)
		return 0;

	pgdp = pgd_offset_k(addr);
	if (pgd_none(READ_ONCE(*pgdp)))
		return 0;

	p4dp = p4d_offset(pgdp, addr);
	if (p4d_none(READ_ONCE(*p4dp)))
		return 0;

	pudp = pud_offset(p4dp, addr);
	pud = READ_ONCE(*pudp);
	if (pud_none(pud))
		return 0;

	if (pud_sect(pud))
		return pfn_valid(pud_pfn(pud));

	pmdp = pmd_offset(pudp, addr);
	pmd = READ_ONCE(*pmdp);
	if (pmd_none(pmd))
		return 0;

	if (pmd_sect(pmd))
		return pfn_valid(pmd_pfn(pmd));

	ptep = pte_offset_kernel(pmdp, addr);
	pte = READ_ONCE(*ptep);
	if (pte_none(pte))
		return 0;

	return pfn_valid(pte_pfn(pte));
}

#ifdef CONFIG_MEMORY_HOTPLUG
static void free_hotplug_page_range(struct page *page, size_t size,
				    struct vmem_altmap *altmap)
{
	if (altmap) {
		vmem_altmap_free(altmap, size >> PAGE_SHIFT);
	} else {
		WARN_ON(PageReserved(page));
		free_pages((unsigned long)page_address(page), get_order(size));
	}
}

static void free_hotplug_pgtable_page(struct page *page)
{
	free_hotplug_page_range(page, PAGE_SIZE, NULL);
}

static bool pgtable_range_aligned(unsigned long start, unsigned long end,
				  unsigned long floor, unsigned long ceiling,
				  unsigned long mask)
{
	start &= mask;
	if (start < floor)
		return false;

	if (ceiling) {
		ceiling &= mask;
		if (!ceiling)
			return false;
	}

	if (end - 1 > ceiling - 1)
		return false;
	return true;
}

static void unmap_hotplug_pte_range(pmd_t *pmdp, unsigned long addr,
				    unsigned long end, bool free_mapped,
				    struct vmem_altmap *altmap)
{
	pte_t *ptep, pte;

	do {
		ptep = pte_offset_kernel(pmdp, addr);
		pte = READ_ONCE(*ptep);
		if (pte_none(pte))
			continue;

		WARN_ON(!pte_present(pte));
		pte_clear(&init_mm, addr, ptep);
		flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
		if (free_mapped)
			free_hotplug_page_range(pte_page(pte),
						PAGE_SIZE, altmap);
	} while (addr += PAGE_SIZE, addr < end);
}

static void unmap_hotplug_pmd_range(pud_t *pudp, unsigned long addr,
				    unsigned long end, bool free_mapped,
				    struct vmem_altmap *altmap)
{
	unsigned long next;
	pmd_t *pmdp, pmd;

	do {
		next = pmd_addr_end(addr, end);
		pmdp = pmd_offset(pudp, addr);
		pmd = READ_ONCE(*pmdp);
		if (pmd_none(pmd))
			continue;

		WARN_ON(!pmd_present(pmd));
		if (pmd_sect(pmd)) {
			pmd_clear(pmdp);

			/*
			 * One TLBI should be sufficient here as the PMD_SIZE
			 * range is mapped with a single block entry.
			 */
			flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
			if (free_mapped)
				free_hotplug_page_range(pmd_page(pmd),
							PMD_SIZE, altmap);
			continue;
		}
		WARN_ON(!pmd_table(pmd));
		unmap_hotplug_pte_range(pmdp, addr, next, free_mapped, altmap);
	} while (addr = next, addr < end);
}

static void unmap_hotplug_pud_range(p4d_t *p4dp, unsigned long addr,
				    unsigned long end, bool free_mapped,
				    struct vmem_altmap *altmap)
{
	unsigned long next;
	pud_t *pudp, pud;

	do {
		next = pud_addr_end(addr, end);
		pudp = pud_offset(p4dp, addr);
		pud = READ_ONCE(*pudp);
		if (pud_none(pud))
			continue;

		WARN_ON(!pud_present(pud));
		if (pud_sect(pud)) {
			pud_clear(pudp);

			/*
			 * One TLBI should be sufficient here as the PUD_SIZE
			 * range is mapped with a single block entry.
			 */
			flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
			if (free_mapped)
				free_hotplug_page_range(pud_page(pud),
							PUD_SIZE, altmap);
			continue;
		}
		WARN_ON(!pud_table(pud));
		unmap_hotplug_pmd_range(pudp, addr, next, free_mapped, altmap);
	} while (addr = next, addr < end);
}

static void unmap_hotplug_p4d_range(pgd_t *pgdp, unsigned long addr,
				    unsigned long end, bool free_mapped,
				    struct vmem_altmap *altmap)
{
	unsigned long next;
	p4d_t *p4dp, p4d;

	do {
		next = p4d_addr_end(addr, end);
		p4dp = p4d_offset(pgdp, addr);
		p4d = READ_ONCE(*p4dp);
		if (p4d_none(p4d))
			continue;

		WARN_ON(!p4d_present(p4d));
		unmap_hotplug_pud_range(p4dp, addr, next, free_mapped, altmap);
	} while (addr = next, addr < end);
}

static void unmap_hotplug_range(unsigned long addr, unsigned long end,
				bool free_mapped, struct vmem_altmap *altmap)
{
	unsigned long next;
	pgd_t *pgdp, pgd;

	/*
	 * altmap can only be used as vmemmap mapping backing memory.
	 * In case the backing memory itself is not being freed, then
	 * altmap is irrelevant. Warn about this inconsistency when
	 * encountered.
	 */
	WARN_ON(!free_mapped && altmap);

	do {
		next = pgd_addr_end(addr, end);
		pgdp = pgd_offset_k(addr);
		pgd = READ_ONCE(*pgdp);
		if (pgd_none(pgd))
			continue;

		WARN_ON(!pgd_present(pgd));
		unmap_hotplug_p4d_range(pgdp, addr, next, free_mapped, altmap);
	} while (addr = next, addr < end);
}

static void free_empty_pte_table(pmd_t *pmdp, unsigned long addr,
				 unsigned long end, unsigned long floor,
				 unsigned long ceiling)
{
	pte_t *ptep, pte;
	unsigned long i, start = addr;

	do {
		ptep = pte_offset_kernel(pmdp, addr);
		pte = READ_ONCE(*ptep);

		/*
		 * This is just a sanity check here which verifies that
		 * pte clearing has been done by earlier unmap loops.
		 */
		WARN_ON(!pte_none(pte));
	} while (addr += PAGE_SIZE, addr < end);

	if (!pgtable_range_aligned(start, end, floor, ceiling, PMD_MASK))
		return;

	/*
	 * Check whether we can free the pte page if the rest of the
	 * entries are empty. Overlap with other regions have been
	 * handled by the floor/ceiling check.
	 */
	ptep = pte_offset_kernel(pmdp, 0UL);
	for (i = 0; i < PTRS_PER_PTE; i++) {
		if (!pte_none(READ_ONCE(ptep[i])))
			return;
	}

	pmd_clear(pmdp);
	__flush_tlb_kernel_pgtable(start);
	free_hotplug_pgtable_page(virt_to_page(ptep));
}

static void free_empty_pmd_table(pud_t *pudp, unsigned long addr,
				 unsigned long end, unsigned long floor,
				 unsigned long ceiling)
{
	pmd_t *pmdp, pmd;
	unsigned long i, next, start = addr;

	do {
		next = pmd_addr_end(addr, end);
		pmdp = pmd_offset(pudp, addr);
		pmd = READ_ONCE(*pmdp);
		if (pmd_none(pmd))
			continue;

		WARN_ON(!pmd_present(pmd) || !pmd_table(pmd) || pmd_sect(pmd));
		free_empty_pte_table(pmdp, addr, next, floor, ceiling);
	} while (addr = next, addr < end);

	if (CONFIG_PGTABLE_LEVELS <= 2)
		return;

	if (!pgtable_range_aligned(start, end, floor, ceiling, PUD_MASK))
		return;

	/*
	 * Check whether we can free the pmd page if the rest of the
	 * entries are empty. Overlap with other regions have been
	 * handled by the floor/ceiling check.
	 */
	pmdp = pmd_offset(pudp, 0UL);
	for (i = 0; i < PTRS_PER_PMD; i++) {
		if (!pmd_none(READ_ONCE(pmdp[i])))
			return;
	}

	pud_clear(pudp);
	__flush_tlb_kernel_pgtable(start);
	free_hotplug_pgtable_page(virt_to_page(pmdp));
}

static void free_empty_pud_table(p4d_t *p4dp, unsigned long addr,
				 unsigned long end, unsigned long floor,
				 unsigned long ceiling)
{
	pud_t *pudp, pud;
	unsigned long i, next, start = addr;

	do {
		next = pud_addr_end(addr, end);
		pudp = pud_offset(p4dp, addr);
		pud = READ_ONCE(*pudp);
		if (pud_none(pud))
			continue;

		WARN_ON(!pud_present(pud) || !pud_table(pud) || pud_sect(pud));
		free_empty_pmd_table(pudp, addr, next, floor, ceiling);
	} while (addr = next, addr < end);

	if (CONFIG_PGTABLE_LEVELS <= 3)
		return;

	if (!pgtable_range_aligned(start, end, floor, ceiling, PGDIR_MASK))
		return;

	/*
	 * Check whether we can free the pud page if the rest of the
	 * entries are empty. Overlap with other regions have been
	 * handled by the floor/ceiling check.
	 */
	pudp = pud_offset(p4dp, 0UL);
	for (i = 0; i < PTRS_PER_PUD; i++) {
		if (!pud_none(READ_ONCE(pudp[i])))
			return;
	}

	p4d_clear(p4dp);
	__flush_tlb_kernel_pgtable(start);
	free_hotplug_pgtable_page(virt_to_page(pudp));
}

static void free_empty_p4d_table(pgd_t *pgdp, unsigned long addr,
				 unsigned long end, unsigned long floor,
				 unsigned long ceiling)
{
	unsigned long next;
	p4d_t *p4dp, p4d;

	do {
		next = p4d_addr_end(addr, end);
		p4dp = p4d_offset(pgdp, addr);
		p4d = READ_ONCE(*p4dp);
		if (p4d_none(p4d))
			continue;

		WARN_ON(!p4d_present(p4d));
		free_empty_pud_table(p4dp, addr, next, floor, ceiling);
	} while (addr = next, addr < end);
}

static void free_empty_tables(unsigned long addr, unsigned long end,
			      unsigned long floor, unsigned long ceiling)
{
	unsigned long next;
	pgd_t *pgdp, pgd;

	do {
		next = pgd_addr_end(addr, end);
		pgdp = pgd_offset_k(addr);
		pgd = READ_ONCE(*pgdp);
		if (pgd_none(pgd))
			continue;

		WARN_ON(!pgd_present(pgd));
		free_empty_p4d_table(pgdp, addr, next, floor, ceiling);
	} while (addr = next, addr < end);
}
#endif

#if !ARM64_SWAPPER_USES_SECTION_MAPS
int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
		struct vmem_altmap *altmap)
{
	WARN_ON((start < VMEMMAP_START) || (end > VMEMMAP_END));
	return vmemmap_populate_basepages(start, end, node, altmap);
}
#else	/* !ARM64_SWAPPER_USES_SECTION_MAPS */
int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
		struct vmem_altmap *altmap)
{
	unsigned long addr = start;
	unsigned long next;
	pgd_t *pgdp;
	p4d_t *p4dp;
	pud_t *pudp;
	pmd_t *pmdp;

	WARN_ON((start < VMEMMAP_START) || (end > VMEMMAP_END));
	do {
		next = pmd_addr_end(addr, end);

		pgdp = vmemmap_pgd_populate(addr, node);
		if (!pgdp)
			return -ENOMEM;

		p4dp = vmemmap_p4d_populate(pgdp, addr, node);
		if (!p4dp)
			return -ENOMEM;

		pudp = vmemmap_pud_populate(p4dp, addr, node);
		if (!pudp)
			return -ENOMEM;

		pmdp = pmd_offset(pudp, addr);
		if (pmd_none(READ_ONCE(*pmdp))) {
			void *p = NULL;

			p = vmemmap_alloc_block_buf(PMD_SIZE, node, altmap);
			if (!p) {
				if (vmemmap_populate_basepages(addr, next, node, altmap))
					return -ENOMEM;
				continue;
			}

			pmd_set_huge(pmdp, __pa(p), __pgprot(PROT_SECT_NORMAL));
		} else
			vmemmap_verify((pte_t *)pmdp, node, addr, next);
	} while (addr = next, addr != end);

	return 0;
}
#endif	/* !ARM64_SWAPPER_USES_SECTION_MAPS */
void vmemmap_free(unsigned long start, unsigned long end,
		struct vmem_altmap *altmap)
{
#ifdef CONFIG_MEMORY_HOTPLUG
	WARN_ON((start < VMEMMAP_START) || (end > VMEMMAP_END));

	unmap_hotplug_range(start, end, true, altmap);
	free_empty_tables(start, end, VMEMMAP_START, VMEMMAP_END);
#endif
}

static inline pud_t *fixmap_pud(unsigned long addr)
{
	pgd_t *pgdp = pgd_offset_k(addr);
	p4d_t *p4dp = p4d_offset(pgdp, addr);
	p4d_t p4d = READ_ONCE(*p4dp);

	BUG_ON(p4d_none(p4d) || p4d_bad(p4d));

	return pud_offset_kimg(p4dp, addr);
}

static inline pmd_t *fixmap_pmd(unsigned long addr)
{
	pud_t *pudp = fixmap_pud(addr);
	pud_t pud = READ_ONCE(*pudp);

	BUG_ON(pud_none(pud) || pud_bad(pud));

	return pmd_offset_kimg(pudp, addr);
}

static inline pte_t *fixmap_pte(unsigned long addr)
{
	return &bm_pte[pte_index(addr)];
}

/*
 * The p*d_populate functions call virt_to_phys implicitly so they can't be used
 * directly on kernel symbols (bm_p*d). This function is called too early to use
 * lm_alias so __p*d_populate functions must be used to populate with the
 * physical address from __pa_symbol.
 */
void __init early_fixmap_init(void)
{
	pgd_t *pgdp;
	p4d_t *p4dp, p4d;
	pud_t *pudp;
	pmd_t *pmdp;
	unsigned long addr = FIXADDR_START;

	pgdp = pgd_offset_k(addr);
	p4dp = p4d_offset(pgdp, addr);
	p4d = READ_ONCE(*p4dp);
	if (CONFIG_PGTABLE_LEVELS > 3 &&
	    !(p4d_none(p4d) || p4d_page_paddr(p4d) == __pa_symbol(bm_pud))) {
		/*
		 * We only end up here if the kernel mapping and the fixmap
		 * share the top level pgd entry, which should only happen on
		 * 16k/4 levels configurations.
		 */
		BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES));
		pudp = pud_offset_kimg(p4dp, addr);
	} else {
		if (p4d_none(p4d))
			__p4d_populate(p4dp, __pa_symbol(bm_pud), P4D_TYPE_TABLE);
		pudp = fixmap_pud(addr);
	}
	if (pud_none(READ_ONCE(*pudp)))
		__pud_populate(pudp, __pa_symbol(bm_pmd), PUD_TYPE_TABLE);
	pmdp = fixmap_pmd(addr);
	__pmd_populate(pmdp, __pa_symbol(bm_pte), PMD_TYPE_TABLE);

	/*
	 * The boot-ioremap range spans multiple pmds, for which
	 * we are not prepared:
	 */
	BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT)
		     != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT));

	if ((pmdp != fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)))
	     || pmdp != fixmap_pmd(fix_to_virt(FIX_BTMAP_END))) {
		WARN_ON(1);
		pr_warn("pmdp %p != %p, %p\n",
			pmdp, fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)),
			fixmap_pmd(fix_to_virt(FIX_BTMAP_END)));
		pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n",
			fix_to_virt(FIX_BTMAP_BEGIN));
		pr_warn("fix_to_virt(FIX_BTMAP_END):   %08lx\n",
			fix_to_virt(FIX_BTMAP_END));

		pr_warn("FIX_BTMAP_END:       %d\n", FIX_BTMAP_END);
		pr_warn("FIX_BTMAP_BEGIN:     %d\n", FIX_BTMAP_BEGIN);
	}
}

/*
 * Unusually, this is also called in IRQ context (ghes_iounmap_irq) so if we
 * ever need to use IPIs for TLB broadcasting, then we're in trouble here.
 */
void __set_fixmap(enum fixed_addresses idx,
			       phys_addr_t phys, pgprot_t flags)
{
	unsigned long addr = __fix_to_virt(idx);
	pte_t *ptep;

	BUG_ON(idx <= FIX_HOLE || idx >= __end_of_fixed_addresses);

	ptep = fixmap_pte(addr);

	if (pgprot_val(flags)) {
		set_pte(ptep, pfn_pte(phys >> PAGE_SHIFT, flags));
	} else {
		pte_clear(&init_mm, addr, ptep);
		flush_tlb_kernel_range(addr, addr+PAGE_SIZE);
	}
}

void *__init fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot)
{
	const u64 dt_virt_base = __fix_to_virt(FIX_FDT);
	int offset;
	void *dt_virt;

	/*
	 * Check whether the physical FDT address is set and meets the minimum
	 * alignment requirement. Since we are relying on MIN_FDT_ALIGN to be
	 * at least 8 bytes so that we can always access the magic and size
	 * fields of the FDT header after mapping the first chunk, double check
	 * here if that is indeed the case.
	 */
	BUILD_BUG_ON(MIN_FDT_ALIGN < 8);
	if (!dt_phys || dt_phys % MIN_FDT_ALIGN)
		return NULL;

	/*
	 * Make sure that the FDT region can be mapped without the need to
	 * allocate additional translation table pages, so that it is safe
	 * to call create_mapping_noalloc() this early.
	 *
	 * On 64k pages, the FDT will be mapped using PTEs, so we need to
	 * be in the same PMD as the rest of the fixmap.
	 * On 4k pages, we'll use section mappings for the FDT so we only
	 * have to be in the same PUD.
	 */
	BUILD_BUG_ON(dt_virt_base % SZ_2M);

	BUILD_BUG_ON(__fix_to_virt(FIX_FDT_END) >> SWAPPER_TABLE_SHIFT !=
		     __fix_to_virt(FIX_BTMAP_BEGIN) >> SWAPPER_TABLE_SHIFT);

	offset = dt_phys % SWAPPER_BLOCK_SIZE;
	dt_virt = (void *)dt_virt_base + offset;

	/* map the first chunk so we can read the size from the header */
	create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE),
			dt_virt_base, SWAPPER_BLOCK_SIZE, prot);

	if (fdt_magic(dt_virt) != FDT_MAGIC)
		return NULL;

	*size = fdt_totalsize(dt_virt);
	if (*size > MAX_FDT_SIZE)
		return NULL;

	if (offset + *size > SWAPPER_BLOCK_SIZE)
		create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE), dt_virt_base,
			       round_up(offset + *size, SWAPPER_BLOCK_SIZE), prot);

	return dt_virt;
}

#if CONFIG_PGTABLE_LEVELS > 3
int pud_set_huge(pud_t *pudp, phys_addr_t phys, pgprot_t prot)
{
	pud_t new_pud = pfn_pud(__phys_to_pfn(phys), mk_pud_sect_prot(prot));

	/* Only allow permission changes for now */
	if (!pgattr_change_is_safe(READ_ONCE(pud_val(*pudp)),
				   pud_val(new_pud)))
		return 0;

	VM_BUG_ON(phys & ~PUD_MASK);
	set_pud(pudp, new_pud);
	return 1;
}

int pud_clear_huge(pud_t *pudp)
{
	if (!pud_sect(READ_ONCE(*pudp)))
		return 0;
	pud_clear(pudp);
	return 1;
}
#endif

#if CONFIG_PGTABLE_LEVELS > 2
int pmd_set_huge(pmd_t *pmdp, phys_addr_t phys, pgprot_t prot)
{
	pmd_t new_pmd = pfn_pmd(__phys_to_pfn(phys), mk_pmd_sect_prot(prot));

	/* Only allow permission changes for now */
	if (!pgattr_change_is_safe(READ_ONCE(pmd_val(*pmdp)),
				   pmd_val(new_pmd)))
		return 0;

	VM_BUG_ON(phys & ~PMD_MASK);
	set_pmd(pmdp, new_pmd);
	return 1;
}

int pmd_clear_huge(pmd_t *pmdp)
{
	if (!pmd_sect(READ_ONCE(*pmdp)))
		return 0;
	pmd_clear(pmdp);
	return 1;
}
#endif

int pmd_free_pte_page(pmd_t *pmdp, unsigned long addr)
{
	pte_t *table;
	pmd_t pmd;

	pmd = READ_ONCE(*pmdp);

	if (!pmd_table(pmd)) {
		VM_WARN_ON(1);
		return 1;
	}

	table = pte_offset_kernel(pmdp, addr);
	pmd_clear(pmdp);
	__flush_tlb_kernel_pgtable(addr);
	pte_free_kernel(NULL, table);
	return 1;
}

int pud_free_pmd_page(pud_t *pudp, unsigned long addr)
{
	pmd_t *table;
	pmd_t *pmdp;
	pud_t pud;
	unsigned long next, end;

	pud = READ_ONCE(*pudp);

	if (!pud_table(pud)) {
		VM_WARN_ON(1);
		return 1;
	}

	table = pmd_offset(pudp, addr);
	pmdp = table;
	next = addr;
	end = addr + PUD_SIZE;
	do {
		pmd_free_pte_page(pmdp, next);
	} while (pmdp++, next += PMD_SIZE, next != end);

	pud_clear(pudp);
	__flush_tlb_kernel_pgtable(addr);
	pmd_free(NULL, table);
	return 1;
}

#ifdef CONFIG_MEMORY_HOTPLUG
static void __remove_pgd_mapping(pgd_t *pgdir, unsigned long start, u64 size)
{
	unsigned long end = start + size;

	WARN_ON(pgdir != init_mm.pgd);
	WARN_ON((start < PAGE_OFFSET) || (end > PAGE_END));

	unmap_hotplug_range(start, end, false, NULL);
	free_empty_tables(start, end, PAGE_OFFSET, PAGE_END);
}

struct range arch_get_mappable_range(void)
{
	struct range mhp_range;
	u64 start_linear_pa = __pa(_PAGE_OFFSET(vabits_actual));
	u64 end_linear_pa = __pa(PAGE_END - 1);

	if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {
		/*
		 * Check for a wrap, it is possible because of randomized linear
		 * mapping the start physical address is actually bigger than
		 * the end physical address. In this case set start to zero
		 * because [0, end_linear_pa] range must still be able to cover
		 * all addressable physical addresses.
		 */
		if (start_linear_pa > end_linear_pa)
			start_linear_pa = 0;
	}

	WARN_ON(start_linear_pa > end_linear_pa);

	/*
	 * Linear mapping region is the range [PAGE_OFFSET..(PAGE_END - 1)]
	 * accommodating both its ends but excluding PAGE_END. Max physical
	 * range which can be mapped inside this linear mapping range, must
	 * also be derived from its end points.
	 */
	mhp_range.start = start_linear_pa;
	mhp_range.end =  end_linear_pa;

	return mhp_range;
}

int arch_add_memory(int nid, u64 start, u64 size,
		    struct mhp_params *params)
{
	int ret, flags = NO_EXEC_MAPPINGS;

	VM_BUG_ON(!mhp_range_allowed(start, size, true));

	/*
	 * KFENCE requires linear map to be mapped at page granularity, so that
	 * it is possible to protect/unprotect single pages in the KFENCE pool.
	 */
	if (rodata_full || debug_pagealloc_enabled() ||
	    IS_ENABLED(CONFIG_KFENCE))
		flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;

	__create_pgd_mapping(swapper_pg_dir, start, __phys_to_virt(start),
			     size, params->pgprot, __pgd_pgtable_alloc,
			     flags);

	memblock_clear_nomap(start, size);

	ret = __add_pages(nid, start >> PAGE_SHIFT, size >> PAGE_SHIFT,
			   params);
	if (ret)
		__remove_pgd_mapping(swapper_pg_dir,
				     __phys_to_virt(start), size);
	return ret;
}

void arch_remove_memory(int nid, u64 start, u64 size,
			struct vmem_altmap *altmap)
{
	unsigned long start_pfn = start >> PAGE_SHIFT;
	unsigned long nr_pages = size >> PAGE_SHIFT;

	__remove_pages(start_pfn, nr_pages, altmap);
	__remove_pgd_mapping(swapper_pg_dir, __phys_to_virt(start), size);
}

/*
 * This memory hotplug notifier helps prevent boot memory from being
 * inadvertently removed as it blocks pfn range offlining process in
 * __offline_pages(). Hence this prevents both offlining as well as
 * removal process for boot memory which is initially always online.
 * In future if and when boot memory could be removed, this notifier
 * should be dropped and free_hotplug_page_range() should handle any
 * reserved pages allocated during boot.
 */
static int prevent_bootmem_remove_notifier(struct notifier_block *nb,
					   unsigned long action, void *data)
{
	struct mem_section *ms;
	struct memory_notify *arg = data;
	unsigned long end_pfn = arg->start_pfn + arg->nr_pages;
	unsigned long pfn = arg->start_pfn;

	if ((action != MEM_GOING_OFFLINE) && (action != MEM_OFFLINE))
		return NOTIFY_OK;

	for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
		unsigned long start = PFN_PHYS(pfn);
		unsigned long end = start + (1UL << PA_SECTION_SHIFT);

		ms = __pfn_to_section(pfn);
		if (!early_section(ms))
			continue;

		if (action == MEM_GOING_OFFLINE) {
			/*
			 * Boot memory removal is not supported. Prevent
			 * it via blocking any attempted offline request
			 * for the boot memory and just report it.
			 */
			pr_warn("Boot memory [%lx %lx] offlining attempted\n", start, end);
			return NOTIFY_BAD;
		} else if (action == MEM_OFFLINE) {
			/*
			 * This should have never happened. Boot memory
			 * offlining should have been prevented by this
			 * very notifier. Probably some memory removal
			 * procedure might have changed which would then
			 * require further debug.
			 */
			pr_err("Boot memory [%lx %lx] offlined\n", start, end);

			/*
			 * Core memory hotplug does not process a return
			 * code from the notifier for MEM_OFFLINE events.
			 * The error condition has been reported. Return
			 * from here as if ignored.
			 */
			return NOTIFY_DONE;
		}
	}
	return NOTIFY_OK;
}

static struct notifier_block prevent_bootmem_remove_nb = {
	.notifier_call = prevent_bootmem_remove_notifier,
};

/*
 * This ensures that boot memory sections on the platform are online
 * from early boot. Memory sections could not be prevented from being
 * offlined, unless for some reason they are not online to begin with.
 * This helps validate the basic assumption on which the above memory
 * event notifier works to prevent boot memory section offlining and
 * its possible removal.
 */
static void validate_bootmem_online(void)
{
	phys_addr_t start, end, addr;
	struct mem_section *ms;
	u64 i;

	/*
	 * Scanning across all memblock might be expensive
	 * on some big memory systems. Hence enable this
	 * validation only with DEBUG_VM.
	 */
	if (!IS_ENABLED(CONFIG_DEBUG_VM))
		return;

	for_each_mem_range(i, &start, &end) {
		for (addr = start; addr < end; addr += (1UL << PA_SECTION_SHIFT)) {
			ms = __pfn_to_section(PHYS_PFN(addr));

			/*
			 * All memory ranges in the system at this point
			 * should have been marked as early sections.
			 */
			WARN_ON(!early_section(ms));

			/*
			 * Memory notifier mechanism here to prevent boot
			 * memory offlining depends on the fact that each
			 * early section memory on the system is initially
			 * online. Otherwise a given memory section which
			 * is already offline will be overlooked and can
			 * be removed completely. Call out such sections.
			 */
			if (!online_section(ms))
				pr_err("Boot memory [%llx %llx] is offline, can be removed\n",
					addr, addr + (1UL << PA_SECTION_SHIFT));
		}
	}
}

static int __init prevent_bootmem_remove_init(void)
{
	int ret = 0;

	if (!IS_ENABLED(CONFIG_MEMORY_HOTREMOVE))
		return ret;

	validate_bootmem_online();
	ret = register_memory_notifier(&prevent_bootmem_remove_nb);
	if (ret)
		pr_err("%s: Notifier registration failed %d\n", __func__, ret);

	return ret;
}
early_initcall(prevent_bootmem_remove_init);
#endif