summaryrefslogtreecommitdiff
path: root/include/linux/pgtable.h
blob: 6e274da637fd7929b94ffe659f545ddc56af60ea (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
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_PGTABLE_H
#define _LINUX_PGTABLE_H

#include <linux/pfn.h>
#include <asm/pgtable.h>

#ifndef __ASSEMBLY__
#ifdef CONFIG_MMU

#include <linux/mm_types.h>
#include <linux/bug.h>
#include <linux/errno.h>
#include <asm-generic/pgtable_uffd.h>

#if 5 - defined(__PAGETABLE_P4D_FOLDED) - defined(__PAGETABLE_PUD_FOLDED) - \
	defined(__PAGETABLE_PMD_FOLDED) != CONFIG_PGTABLE_LEVELS
#error CONFIG_PGTABLE_LEVELS is not consistent with __PAGETABLE_{P4D,PUD,PMD}_FOLDED
#endif

/*
 * On almost all architectures and configurations, 0 can be used as the
 * upper ceiling to free_pgtables(): on many architectures it has the same
 * effect as using TASK_SIZE.  However, there is one configuration which
 * must impose a more careful limit, to avoid freeing kernel pgtables.
 */
#ifndef USER_PGTABLES_CEILING
#define USER_PGTABLES_CEILING	0UL
#endif

#ifndef __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
extern int ptep_set_access_flags(struct vm_area_struct *vma,
				 unsigned long address, pte_t *ptep,
				 pte_t entry, int dirty);
#endif

#ifndef __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
extern int pmdp_set_access_flags(struct vm_area_struct *vma,
				 unsigned long address, pmd_t *pmdp,
				 pmd_t entry, int dirty);
extern int pudp_set_access_flags(struct vm_area_struct *vma,
				 unsigned long address, pud_t *pudp,
				 pud_t entry, int dirty);
#else
static inline int pmdp_set_access_flags(struct vm_area_struct *vma,
					unsigned long address, pmd_t *pmdp,
					pmd_t entry, int dirty)
{
	BUILD_BUG();
	return 0;
}
static inline int pudp_set_access_flags(struct vm_area_struct *vma,
					unsigned long address, pud_t *pudp,
					pud_t entry, int dirty)
{
	BUILD_BUG();
	return 0;
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
#endif

#ifndef __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
static inline int ptep_test_and_clear_young(struct vm_area_struct *vma,
					    unsigned long address,
					    pte_t *ptep)
{
	pte_t pte = *ptep;
	int r = 1;
	if (!pte_young(pte))
		r = 0;
	else
		set_pte_at(vma->vm_mm, address, ptep, pte_mkold(pte));
	return r;
}
#endif

#ifndef __HAVE_ARCH_PMDP_TEST_AND_CLEAR_YOUNG
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,
					    unsigned long address,
					    pmd_t *pmdp)
{
	pmd_t pmd = *pmdp;
	int r = 1;
	if (!pmd_young(pmd))
		r = 0;
	else
		set_pmd_at(vma->vm_mm, address, pmdp, pmd_mkold(pmd));
	return r;
}
#else
static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,
					    unsigned long address,
					    pmd_t *pmdp)
{
	BUILD_BUG();
	return 0;
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
#endif

#ifndef __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
int ptep_clear_flush_young(struct vm_area_struct *vma,
			   unsigned long address, pte_t *ptep);
#endif

#ifndef __HAVE_ARCH_PMDP_CLEAR_YOUNG_FLUSH
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
extern int pmdp_clear_flush_young(struct vm_area_struct *vma,
				  unsigned long address, pmd_t *pmdp);
#else
/*
 * Despite relevant to THP only, this API is called from generic rmap code
 * under PageTransHuge(), hence needs a dummy implementation for !THP
 */
static inline int pmdp_clear_flush_young(struct vm_area_struct *vma,
					 unsigned long address, pmd_t *pmdp)
{
	BUILD_BUG();
	return 0;
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
#endif

#ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR
static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
				       unsigned long address,
				       pte_t *ptep)
{
	pte_t pte = *ptep;
	pte_clear(mm, address, ptep);
	return pte;
}
#endif

#ifdef CONFIG_TRANSPARENT_HUGEPAGE
#ifndef __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR
static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm,
					    unsigned long address,
					    pmd_t *pmdp)
{
	pmd_t pmd = *pmdp;
	pmd_clear(pmdp);
	return pmd;
}
#endif /* __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR */
#ifndef __HAVE_ARCH_PUDP_HUGE_GET_AND_CLEAR
static inline pud_t pudp_huge_get_and_clear(struct mm_struct *mm,
					    unsigned long address,
					    pud_t *pudp)
{
	pud_t pud = *pudp;

	pud_clear(pudp);
	return pud;
}
#endif /* __HAVE_ARCH_PUDP_HUGE_GET_AND_CLEAR */
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */

#ifdef CONFIG_TRANSPARENT_HUGEPAGE
#ifndef __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR_FULL
static inline pmd_t pmdp_huge_get_and_clear_full(struct vm_area_struct *vma,
					    unsigned long address, pmd_t *pmdp,
					    int full)
{
	return pmdp_huge_get_and_clear(vma->vm_mm, address, pmdp);
}
#endif

#ifndef __HAVE_ARCH_PUDP_HUGE_GET_AND_CLEAR_FULL
static inline pud_t pudp_huge_get_and_clear_full(struct mm_struct *mm,
					    unsigned long address, pud_t *pudp,
					    int full)
{
	return pudp_huge_get_and_clear(mm, address, pudp);
}
#endif
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */

#ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR_FULL
static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm,
					    unsigned long address, pte_t *ptep,
					    int full)
{
	pte_t pte;
	pte = ptep_get_and_clear(mm, address, ptep);
	return pte;
}
#endif


/*
 * If two threads concurrently fault at the same page, the thread that
 * won the race updates the PTE and its local TLB/Cache. The other thread
 * gives up, simply does nothing, and continues; on architectures where
 * software can update TLB,  local TLB can be updated here to avoid next page
 * fault. This function updates TLB only, do nothing with cache or others.
 * It is the difference with function update_mmu_cache.
 */
#ifndef __HAVE_ARCH_UPDATE_MMU_TLB
static inline void update_mmu_tlb(struct vm_area_struct *vma,
				unsigned long address, pte_t *ptep)
{
}
#define __HAVE_ARCH_UPDATE_MMU_TLB
#endif

/*
 * Some architectures may be able to avoid expensive synchronization
 * primitives when modifications are made to PTE's which are already
 * not present, or in the process of an address space destruction.
 */
#ifndef __HAVE_ARCH_PTE_CLEAR_NOT_PRESENT_FULL
static inline void pte_clear_not_present_full(struct mm_struct *mm,
					      unsigned long address,
					      pte_t *ptep,
					      int full)
{
	pte_clear(mm, address, ptep);
}
#endif

#ifndef __HAVE_ARCH_PTEP_CLEAR_FLUSH
extern pte_t ptep_clear_flush(struct vm_area_struct *vma,
			      unsigned long address,
			      pte_t *ptep);
#endif

#ifndef __HAVE_ARCH_PMDP_HUGE_CLEAR_FLUSH
extern pmd_t pmdp_huge_clear_flush(struct vm_area_struct *vma,
			      unsigned long address,
			      pmd_t *pmdp);
extern pud_t pudp_huge_clear_flush(struct vm_area_struct *vma,
			      unsigned long address,
			      pud_t *pudp);
#endif

#ifndef __HAVE_ARCH_PTEP_SET_WRPROTECT
struct mm_struct;
static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long address, pte_t *ptep)
{
	pte_t old_pte = *ptep;
	set_pte_at(mm, address, ptep, pte_wrprotect(old_pte));
}
#endif

/*
 * On some architectures hardware does not set page access bit when accessing
 * memory page, it is responsibilty of software setting this bit. It brings
 * out extra page fault penalty to track page access bit. For optimization page
 * access bit can be set during all page fault flow on these arches.
 * To be differentiate with macro pte_mkyoung, this macro is used on platforms
 * where software maintains page access bit.
 */
#ifndef pte_sw_mkyoung
static inline pte_t pte_sw_mkyoung(pte_t pte)
{
	return pte;
}
#define pte_sw_mkyoung	pte_sw_mkyoung
#endif

#ifndef pte_savedwrite
#define pte_savedwrite pte_write
#endif

#ifndef pte_mk_savedwrite
#define pte_mk_savedwrite pte_mkwrite
#endif

#ifndef pte_clear_savedwrite
#define pte_clear_savedwrite pte_wrprotect
#endif

#ifndef pmd_savedwrite
#define pmd_savedwrite pmd_write
#endif

#ifndef pmd_mk_savedwrite
#define pmd_mk_savedwrite pmd_mkwrite
#endif

#ifndef pmd_clear_savedwrite
#define pmd_clear_savedwrite pmd_wrprotect
#endif

#ifndef __HAVE_ARCH_PMDP_SET_WRPROTECT
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
static inline void pmdp_set_wrprotect(struct mm_struct *mm,
				      unsigned long address, pmd_t *pmdp)
{
	pmd_t old_pmd = *pmdp;
	set_pmd_at(mm, address, pmdp, pmd_wrprotect(old_pmd));
}
#else
static inline void pmdp_set_wrprotect(struct mm_struct *mm,
				      unsigned long address, pmd_t *pmdp)
{
	BUILD_BUG();
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
#endif
#ifndef __HAVE_ARCH_PUDP_SET_WRPROTECT
#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
static inline void pudp_set_wrprotect(struct mm_struct *mm,
				      unsigned long address, pud_t *pudp)
{
	pud_t old_pud = *pudp;

	set_pud_at(mm, address, pudp, pud_wrprotect(old_pud));
}
#else
static inline void pudp_set_wrprotect(struct mm_struct *mm,
				      unsigned long address, pud_t *pudp)
{
	BUILD_BUG();
}
#endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
#endif

#ifndef pmdp_collapse_flush
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
extern pmd_t pmdp_collapse_flush(struct vm_area_struct *vma,
				 unsigned long address, pmd_t *pmdp);
#else
static inline pmd_t pmdp_collapse_flush(struct vm_area_struct *vma,
					unsigned long address,
					pmd_t *pmdp)
{
	BUILD_BUG();
	return *pmdp;
}
#define pmdp_collapse_flush pmdp_collapse_flush
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
#endif

#ifndef __HAVE_ARCH_PGTABLE_DEPOSIT
extern void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
				       pgtable_t pgtable);
#endif

#ifndef __HAVE_ARCH_PGTABLE_WITHDRAW
extern pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp);
#endif

#ifdef CONFIG_TRANSPARENT_HUGEPAGE
/*
 * This is an implementation of pmdp_establish() that is only suitable for an
 * architecture that doesn't have hardware dirty/accessed bits. In this case we
 * can't race with CPU which sets these bits and non-atomic aproach is fine.
 */
static inline pmd_t generic_pmdp_establish(struct vm_area_struct *vma,
		unsigned long address, pmd_t *pmdp, pmd_t pmd)
{
	pmd_t old_pmd = *pmdp;
	set_pmd_at(vma->vm_mm, address, pmdp, pmd);
	return old_pmd;
}
#endif

#ifndef __HAVE_ARCH_PMDP_INVALIDATE
extern pmd_t pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
			    pmd_t *pmdp);
#endif

#ifndef __HAVE_ARCH_PTE_SAME
static inline int pte_same(pte_t pte_a, pte_t pte_b)
{
	return pte_val(pte_a) == pte_val(pte_b);
}
#endif

#ifndef __HAVE_ARCH_PTE_UNUSED
/*
 * Some architectures provide facilities to virtualization guests
 * so that they can flag allocated pages as unused. This allows the
 * host to transparently reclaim unused pages. This function returns
 * whether the pte's page is unused.
 */
static inline int pte_unused(pte_t pte)
{
	return 0;
}
#endif

#ifndef pte_access_permitted
#define pte_access_permitted(pte, write) \
	(pte_present(pte) && (!(write) || pte_write(pte)))
#endif

#ifndef pmd_access_permitted
#define pmd_access_permitted(pmd, write) \
	(pmd_present(pmd) && (!(write) || pmd_write(pmd)))
#endif

#ifndef pud_access_permitted
#define pud_access_permitted(pud, write) \
	(pud_present(pud) && (!(write) || pud_write(pud)))
#endif

#ifndef p4d_access_permitted
#define p4d_access_permitted(p4d, write) \
	(p4d_present(p4d) && (!(write) || p4d_write(p4d)))
#endif

#ifndef pgd_access_permitted
#define pgd_access_permitted(pgd, write) \
	(pgd_present(pgd) && (!(write) || pgd_write(pgd)))
#endif

#ifndef __HAVE_ARCH_PMD_SAME
static inline int pmd_same(pmd_t pmd_a, pmd_t pmd_b)
{
	return pmd_val(pmd_a) == pmd_val(pmd_b);
}

static inline int pud_same(pud_t pud_a, pud_t pud_b)
{
	return pud_val(pud_a) == pud_val(pud_b);
}
#endif

#ifndef __HAVE_ARCH_P4D_SAME
static inline int p4d_same(p4d_t p4d_a, p4d_t p4d_b)
{
	return p4d_val(p4d_a) == p4d_val(p4d_b);
}
#endif

#ifndef __HAVE_ARCH_PGD_SAME
static inline int pgd_same(pgd_t pgd_a, pgd_t pgd_b)
{
	return pgd_val(pgd_a) == pgd_val(pgd_b);
}
#endif

/*
 * Use set_p*_safe(), and elide TLB flushing, when confident that *no*
 * TLB flush will be required as a result of the "set". For example, use
 * in scenarios where it is known ahead of time that the routine is
 * setting non-present entries, or re-setting an existing entry to the
 * same value. Otherwise, use the typical "set" helpers and flush the
 * TLB.
 */
#define set_pte_safe(ptep, pte) \
({ \
	WARN_ON_ONCE(pte_present(*ptep) && !pte_same(*ptep, pte)); \
	set_pte(ptep, pte); \
})

#define set_pmd_safe(pmdp, pmd) \
({ \
	WARN_ON_ONCE(pmd_present(*pmdp) && !pmd_same(*pmdp, pmd)); \
	set_pmd(pmdp, pmd); \
})

#define set_pud_safe(pudp, pud) \
({ \
	WARN_ON_ONCE(pud_present(*pudp) && !pud_same(*pudp, pud)); \
	set_pud(pudp, pud); \
})

#define set_p4d_safe(p4dp, p4d) \
({ \
	WARN_ON_ONCE(p4d_present(*p4dp) && !p4d_same(*p4dp, p4d)); \
	set_p4d(p4dp, p4d); \
})

#define set_pgd_safe(pgdp, pgd) \
({ \
	WARN_ON_ONCE(pgd_present(*pgdp) && !pgd_same(*pgdp, pgd)); \
	set_pgd(pgdp, pgd); \
})

#ifndef __HAVE_ARCH_DO_SWAP_PAGE
/*
 * Some architectures support metadata associated with a page. When a
 * page is being swapped out, this metadata must be saved so it can be
 * restored when the page is swapped back in. SPARC M7 and newer
 * processors support an ADI (Application Data Integrity) tag for the
 * page as metadata for the page. arch_do_swap_page() can restore this
 * metadata when a page is swapped back in.
 */
static inline void arch_do_swap_page(struct mm_struct *mm,
				     struct vm_area_struct *vma,
				     unsigned long addr,
				     pte_t pte, pte_t oldpte)
{

}
#endif

#ifndef __HAVE_ARCH_UNMAP_ONE
/*
 * Some architectures support metadata associated with a page. When a
 * page is being swapped out, this metadata must be saved so it can be
 * restored when the page is swapped back in. SPARC M7 and newer
 * processors support an ADI (Application Data Integrity) tag for the
 * page as metadata for the page. arch_unmap_one() can save this
 * metadata on a swap-out of a page.
 */
static inline int arch_unmap_one(struct mm_struct *mm,
				  struct vm_area_struct *vma,
				  unsigned long addr,
				  pte_t orig_pte)
{
	return 0;
}
#endif

#ifndef __HAVE_ARCH_PGD_OFFSET_GATE
#define pgd_offset_gate(mm, addr)	pgd_offset(mm, addr)
#endif

#ifndef __HAVE_ARCH_MOVE_PTE
#define move_pte(pte, prot, old_addr, new_addr)	(pte)
#endif

#ifndef pte_accessible
# define pte_accessible(mm, pte)	((void)(pte), 1)
#endif

#ifndef flush_tlb_fix_spurious_fault
#define flush_tlb_fix_spurious_fault(vma, address) flush_tlb_page(vma, address)
#endif

#ifndef pgprot_nx
#define pgprot_nx(prot)	(prot)
#endif

#ifndef pgprot_noncached
#define pgprot_noncached(prot)	(prot)
#endif

#ifndef pgprot_writecombine
#define pgprot_writecombine pgprot_noncached
#endif

#ifndef pgprot_writethrough
#define pgprot_writethrough pgprot_noncached
#endif

#ifndef pgprot_device
#define pgprot_device pgprot_noncached
#endif

#ifndef pgprot_modify
#define pgprot_modify pgprot_modify
static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot)
{
	if (pgprot_val(oldprot) == pgprot_val(pgprot_noncached(oldprot)))
		newprot = pgprot_noncached(newprot);
	if (pgprot_val(oldprot) == pgprot_val(pgprot_writecombine(oldprot)))
		newprot = pgprot_writecombine(newprot);
	if (pgprot_val(oldprot) == pgprot_val(pgprot_device(oldprot)))
		newprot = pgprot_device(newprot);
	return newprot;
}
#endif

/*
 * When walking page tables, get the address of the next boundary,
 * or the end address of the range if that comes earlier.  Although no
 * vma end wraps to 0, rounded up __boundary may wrap to 0 throughout.
 */

#define pgd_addr_end(addr, end)						\
({	unsigned long __boundary = ((addr) + PGDIR_SIZE) & PGDIR_MASK;	\
	(__boundary - 1 < (end) - 1)? __boundary: (end);		\
})

#ifndef p4d_addr_end
#define p4d_addr_end(addr, end)						\
({	unsigned long __boundary = ((addr) + P4D_SIZE) & P4D_MASK;	\
	(__boundary - 1 < (end) - 1)? __boundary: (end);		\
})
#endif

#ifndef pud_addr_end
#define pud_addr_end(addr, end)						\
({	unsigned long __boundary = ((addr) + PUD_SIZE) & PUD_MASK;	\
	(__boundary - 1 < (end) - 1)? __boundary: (end);		\
})
#endif

#ifndef pmd_addr_end
#define pmd_addr_end(addr, end)						\
({	unsigned long __boundary = ((addr) + PMD_SIZE) & PMD_MASK;	\
	(__boundary - 1 < (end) - 1)? __boundary: (end);		\
})
#endif

/*
 * When walking page tables, we usually want to skip any p?d_none entries;
 * and any p?d_bad entries - reporting the error before resetting to none.
 * Do the tests inline, but report and clear the bad entry in mm/memory.c.
 */
void pgd_clear_bad(pgd_t *);

#ifndef __PAGETABLE_P4D_FOLDED
void p4d_clear_bad(p4d_t *);
#else
#define p4d_clear_bad(p4d)        do { } while (0)
#endif

#ifndef __PAGETABLE_PUD_FOLDED
void pud_clear_bad(pud_t *);
#else
#define pud_clear_bad(p4d)        do { } while (0)
#endif

void pmd_clear_bad(pmd_t *);

static inline int pgd_none_or_clear_bad(pgd_t *pgd)
{
	if (pgd_none(*pgd))
		return 1;
	if (unlikely(pgd_bad(*pgd))) {
		pgd_clear_bad(pgd);
		return 1;
	}
	return 0;
}

static inline int p4d_none_or_clear_bad(p4d_t *p4d)
{
	if (p4d_none(*p4d))
		return 1;
	if (unlikely(p4d_bad(*p4d))) {
		p4d_clear_bad(p4d);
		return 1;
	}
	return 0;
}

static inline int pud_none_or_clear_bad(pud_t *pud)
{
	if (pud_none(*pud))
		return 1;
	if (unlikely(pud_bad(*pud))) {
		pud_clear_bad(pud);
		return 1;
	}
	return 0;
}

static inline int pmd_none_or_clear_bad(pmd_t *pmd)
{
	if (pmd_none(*pmd))
		return 1;
	if (unlikely(pmd_bad(*pmd))) {
		pmd_clear_bad(pmd);
		return 1;
	}
	return 0;
}

static inline pte_t __ptep_modify_prot_start(struct vm_area_struct *vma,
					     unsigned long addr,
					     pte_t *ptep)
{
	/*
	 * Get the current pte state, but zero it out to make it
	 * non-present, preventing the hardware from asynchronously
	 * updating it.
	 */
	return ptep_get_and_clear(vma->vm_mm, addr, ptep);
}

static inline void __ptep_modify_prot_commit(struct vm_area_struct *vma,
					     unsigned long addr,
					     pte_t *ptep, pte_t pte)
{
	/*
	 * The pte is non-present, so there's no hardware state to
	 * preserve.
	 */
	set_pte_at(vma->vm_mm, addr, ptep, pte);
}

#ifndef __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION
/*
 * Start a pte protection read-modify-write transaction, which
 * protects against asynchronous hardware modifications to the pte.
 * The intention is not to prevent the hardware from making pte
 * updates, but to prevent any updates it may make from being lost.
 *
 * This does not protect against other software modifications of the
 * pte; the appropriate pte lock must be held over the transation.
 *
 * Note that this interface is intended to be batchable, meaning that
 * ptep_modify_prot_commit may not actually update the pte, but merely
 * queue the update to be done at some later time.  The update must be
 * actually committed before the pte lock is released, however.
 */
static inline pte_t ptep_modify_prot_start(struct vm_area_struct *vma,
					   unsigned long addr,
					   pte_t *ptep)
{
	return __ptep_modify_prot_start(vma, addr, ptep);
}

/*
 * Commit an update to a pte, leaving any hardware-controlled bits in
 * the PTE unmodified.
 */
static inline void ptep_modify_prot_commit(struct vm_area_struct *vma,
					   unsigned long addr,
					   pte_t *ptep, pte_t old_pte, pte_t pte)
{
	__ptep_modify_prot_commit(vma, addr, ptep, pte);
}
#endif /* __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION */
#endif /* CONFIG_MMU */

/*
 * No-op macros that just return the current protection value. Defined here
 * because these macros can be used used even if CONFIG_MMU is not defined.
 */
#ifndef pgprot_encrypted
#define pgprot_encrypted(prot)	(prot)
#endif

#ifndef pgprot_decrypted
#define pgprot_decrypted(prot)	(prot)
#endif

/*
 * A facility to provide lazy MMU batching.  This allows PTE updates and
 * page invalidations to be delayed until a call to leave lazy MMU mode
 * is issued.  Some architectures may benefit from doing this, and it is
 * beneficial for both shadow and direct mode hypervisors, which may batch
 * the PTE updates which happen during this window.  Note that using this
 * interface requires that read hazards be removed from the code.  A read
 * hazard could result in the direct mode hypervisor case, since the actual
 * write to the page tables may not yet have taken place, so reads though
 * a raw PTE pointer after it has been modified are not guaranteed to be
 * up to date.  This mode can only be entered and left under the protection of
 * the page table locks for all page tables which may be modified.  In the UP
 * case, this is required so that preemption is disabled, and in the SMP case,
 * it must synchronize the delayed page table writes properly on other CPUs.
 */
#ifndef __HAVE_ARCH_ENTER_LAZY_MMU_MODE
#define arch_enter_lazy_mmu_mode()	do {} while (0)
#define arch_leave_lazy_mmu_mode()	do {} while (0)
#define arch_flush_lazy_mmu_mode()	do {} while (0)
#endif

/*
 * A facility to provide batching of the reload of page tables and
 * other process state with the actual context switch code for
 * paravirtualized guests.  By convention, only one of the batched
 * update (lazy) modes (CPU, MMU) should be active at any given time,
 * entry should never be nested, and entry and exits should always be
 * paired.  This is for sanity of maintaining and reasoning about the
 * kernel code.  In this case, the exit (end of the context switch) is
 * in architecture-specific code, and so doesn't need a generic
 * definition.
 */
#ifndef __HAVE_ARCH_START_CONTEXT_SWITCH
#define arch_start_context_switch(prev)	do {} while (0)
#endif

#ifdef CONFIG_HAVE_ARCH_SOFT_DIRTY
#ifndef CONFIG_ARCH_ENABLE_THP_MIGRATION
static inline pmd_t pmd_swp_mksoft_dirty(pmd_t pmd)
{
	return pmd;
}

static inline int pmd_swp_soft_dirty(pmd_t pmd)
{
	return 0;
}

static inline pmd_t pmd_swp_clear_soft_dirty(pmd_t pmd)
{
	return pmd;
}
#endif
#else /* !CONFIG_HAVE_ARCH_SOFT_DIRTY */
static inline int pte_soft_dirty(pte_t pte)
{
	return 0;
}

static inline int pmd_soft_dirty(pmd_t pmd)
{
	return 0;
}

static inline pte_t pte_mksoft_dirty(pte_t pte)
{
	return pte;
}

static inline pmd_t pmd_mksoft_dirty(pmd_t pmd)
{
	return pmd;
}

static inline pte_t pte_clear_soft_dirty(pte_t pte)
{
	return pte;
}

static inline pmd_t pmd_clear_soft_dirty(pmd_t pmd)
{
	return pmd;
}

static inline pte_t pte_swp_mksoft_dirty(pte_t pte)
{
	return pte;
}

static inline int pte_swp_soft_dirty(pte_t pte)
{
	return 0;
}

static inline pte_t pte_swp_clear_soft_dirty(pte_t pte)
{
	return pte;
}

static inline pmd_t pmd_swp_mksoft_dirty(pmd_t pmd)
{
	return pmd;
}

static inline int pmd_swp_soft_dirty(pmd_t pmd)
{
	return 0;
}

static inline pmd_t pmd_swp_clear_soft_dirty(pmd_t pmd)
{
	return pmd;
}
#endif

#ifndef __HAVE_PFNMAP_TRACKING
/*
 * Interfaces that can be used by architecture code to keep track of
 * memory type of pfn mappings specified by the remap_pfn_range,
 * vmf_insert_pfn.
 */

/*
 * track_pfn_remap is called when a _new_ pfn mapping is being established
 * by remap_pfn_range() for physical range indicated by pfn and size.
 */
static inline int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot,
				  unsigned long pfn, unsigned long addr,
				  unsigned long size)
{
	return 0;
}

/*
 * track_pfn_insert is called when a _new_ single pfn is established
 * by vmf_insert_pfn().
 */
static inline void track_pfn_insert(struct vm_area_struct *vma, pgprot_t *prot,
				    pfn_t pfn)
{
}

/*
 * track_pfn_copy is called when vma that is covering the pfnmap gets
 * copied through copy_page_range().
 */
static inline int track_pfn_copy(struct vm_area_struct *vma)
{
	return 0;
}

/*
 * untrack_pfn is called while unmapping a pfnmap for a region.
 * untrack can be called for a specific region indicated by pfn and size or
 * can be for the entire vma (in which case pfn, size are zero).
 */
static inline void untrack_pfn(struct vm_area_struct *vma,
			       unsigned long pfn, unsigned long size)
{
}

/*
 * untrack_pfn_moved is called while mremapping a pfnmap for a new region.
 */
static inline void untrack_pfn_moved(struct vm_area_struct *vma)
{
}
#else
extern int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot,
			   unsigned long pfn, unsigned long addr,
			   unsigned long size);
extern void track_pfn_insert(struct vm_area_struct *vma, pgprot_t *prot,
			     pfn_t pfn);
extern int track_pfn_copy(struct vm_area_struct *vma);
extern void untrack_pfn(struct vm_area_struct *vma, unsigned long pfn,
			unsigned long size);
extern void untrack_pfn_moved(struct vm_area_struct *vma);
#endif

#ifdef __HAVE_COLOR_ZERO_PAGE
static inline int is_zero_pfn(unsigned long pfn)
{
	extern unsigned long zero_pfn;
	unsigned long offset_from_zero_pfn = pfn - zero_pfn;
	return offset_from_zero_pfn <= (zero_page_mask >> PAGE_SHIFT);
}

#define my_zero_pfn(addr)	page_to_pfn(ZERO_PAGE(addr))

#else
static inline int is_zero_pfn(unsigned long pfn)
{
	extern unsigned long zero_pfn;
	return pfn == zero_pfn;
}

static inline unsigned long my_zero_pfn(unsigned long addr)
{
	extern unsigned long zero_pfn;
	return zero_pfn;
}
#endif

#ifdef CONFIG_MMU

#ifndef CONFIG_TRANSPARENT_HUGEPAGE
static inline int pmd_trans_huge(pmd_t pmd)
{
	return 0;
}
#ifndef pmd_write
static inline int pmd_write(pmd_t pmd)
{
	BUG();
	return 0;
}
#endif /* pmd_write */
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */

#ifndef pud_write
static inline int pud_write(pud_t pud)
{
	BUG();
	return 0;
}
#endif /* pud_write */

#if !defined(CONFIG_ARCH_HAS_PTE_DEVMAP) || !defined(CONFIG_TRANSPARENT_HUGEPAGE)
static inline int pmd_devmap(pmd_t pmd)
{
	return 0;
}
static inline int pud_devmap(pud_t pud)
{
	return 0;
}
static inline int pgd_devmap(pgd_t pgd)
{
	return 0;
}
#endif

#if !defined(CONFIG_TRANSPARENT_HUGEPAGE) || \
	(defined(CONFIG_TRANSPARENT_HUGEPAGE) && \
	 !defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD))
static inline int pud_trans_huge(pud_t pud)
{
	return 0;
}
#endif

/* See pmd_none_or_trans_huge_or_clear_bad for discussion. */
static inline int pud_none_or_trans_huge_or_dev_or_clear_bad(pud_t *pud)
{
	pud_t pudval = READ_ONCE(*pud);

	if (pud_none(pudval) || pud_trans_huge(pudval) || pud_devmap(pudval))
		return 1;
	if (unlikely(pud_bad(pudval))) {
		pud_clear_bad(pud);
		return 1;
	}
	return 0;
}

/* See pmd_trans_unstable for discussion. */
static inline int pud_trans_unstable(pud_t *pud)
{
#if defined(CONFIG_TRANSPARENT_HUGEPAGE) &&			\
	defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD)
	return pud_none_or_trans_huge_or_dev_or_clear_bad(pud);
#else
	return 0;
#endif
}

#ifndef pmd_read_atomic
static inline pmd_t pmd_read_atomic(pmd_t *pmdp)
{
	/*
	 * Depend on compiler for an atomic pmd read. NOTE: this is
	 * only going to work, if the pmdval_t isn't larger than
	 * an unsigned long.
	 */
	return *pmdp;
}
#endif

#ifndef arch_needs_pgtable_deposit
#define arch_needs_pgtable_deposit() (false)
#endif
/*
 * This function is meant to be used by sites walking pagetables with
 * the mmap_sem hold in read mode to protect against MADV_DONTNEED and
 * transhuge page faults. MADV_DONTNEED can convert a transhuge pmd
 * into a null pmd and the transhuge page fault can convert a null pmd
 * into an hugepmd or into a regular pmd (if the hugepage allocation
 * fails). While holding the mmap_sem in read mode the pmd becomes
 * stable and stops changing under us only if it's not null and not a
 * transhuge pmd. When those races occurs and this function makes a
 * difference vs the standard pmd_none_or_clear_bad, the result is
 * undefined so behaving like if the pmd was none is safe (because it
 * can return none anyway). The compiler level barrier() is critically
 * important to compute the two checks atomically on the same pmdval.
 *
 * For 32bit kernels with a 64bit large pmd_t this automatically takes
 * care of reading the pmd atomically to avoid SMP race conditions
 * against pmd_populate() when the mmap_sem is hold for reading by the
 * caller (a special atomic read not done by "gcc" as in the generic
 * version above, is also needed when THP is disabled because the page
 * fault can populate the pmd from under us).
 */
static inline int pmd_none_or_trans_huge_or_clear_bad(pmd_t *pmd)
{
	pmd_t pmdval = pmd_read_atomic(pmd);
	/*
	 * The barrier will stabilize the pmdval in a register or on
	 * the stack so that it will stop changing under the code.
	 *
	 * When CONFIG_TRANSPARENT_HUGEPAGE=y on x86 32bit PAE,
	 * pmd_read_atomic is allowed to return a not atomic pmdval
	 * (for example pointing to an hugepage that has never been
	 * mapped in the pmd). The below checks will only care about
	 * the low part of the pmd with 32bit PAE x86 anyway, with the
	 * exception of pmd_none(). So the important thing is that if
	 * the low part of the pmd is found null, the high part will
	 * be also null or the pmd_none() check below would be
	 * confused.
	 */
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
	barrier();
#endif
	/*
	 * !pmd_present() checks for pmd migration entries
	 *
	 * The complete check uses is_pmd_migration_entry() in linux/swapops.h
	 * But using that requires moving current function and pmd_trans_unstable()
	 * to linux/swapops.h to resovle dependency, which is too much code move.
	 *
	 * !pmd_present() is equivalent to is_pmd_migration_entry() currently,
	 * because !pmd_present() pages can only be under migration not swapped
	 * out.
	 *
	 * pmd_none() is preseved for future condition checks on pmd migration
	 * entries and not confusing with this function name, although it is
	 * redundant with !pmd_present().
	 */
	if (pmd_none(pmdval) || pmd_trans_huge(pmdval) ||
		(IS_ENABLED(CONFIG_ARCH_ENABLE_THP_MIGRATION) && !pmd_present(pmdval)))
		return 1;
	if (unlikely(pmd_bad(pmdval))) {
		pmd_clear_bad(pmd);
		return 1;
	}
	return 0;
}

/*
 * This is a noop if Transparent Hugepage Support is not built into
 * the kernel. Otherwise it is equivalent to
 * pmd_none_or_trans_huge_or_clear_bad(), and shall only be called in
 * places that already verified the pmd is not none and they want to
 * walk ptes while holding the mmap sem in read mode (write mode don't
 * need this). If THP is not enabled, the pmd can't go away under the
 * code even if MADV_DONTNEED runs, but if THP is enabled we need to
 * run a pmd_trans_unstable before walking the ptes after
 * split_huge_pmd returns (because it may have run when the pmd become
 * null, but then a page fault can map in a THP and not a regular page).
 */
static inline int pmd_trans_unstable(pmd_t *pmd)
{
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
	return pmd_none_or_trans_huge_or_clear_bad(pmd);
#else
	return 0;
#endif
}

#ifndef CONFIG_NUMA_BALANCING
/*
 * Technically a PTE can be PROTNONE even when not doing NUMA balancing but
 * the only case the kernel cares is for NUMA balancing and is only ever set
 * when the VMA is accessible. For PROT_NONE VMAs, the PTEs are not marked
 * _PAGE_PROTNONE so by by default, implement the helper as "always no". It
 * is the responsibility of the caller to distinguish between PROT_NONE
 * protections and NUMA hinting fault protections.
 */
static inline int pte_protnone(pte_t pte)
{
	return 0;
}

static inline int pmd_protnone(pmd_t pmd)
{
	return 0;
}
#endif /* CONFIG_NUMA_BALANCING */

#endif /* CONFIG_MMU */

#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP

#ifndef __PAGETABLE_P4D_FOLDED
int p4d_set_huge(p4d_t *p4d, phys_addr_t addr, pgprot_t prot);
int p4d_clear_huge(p4d_t *p4d);
#else
static inline int p4d_set_huge(p4d_t *p4d, phys_addr_t addr, pgprot_t prot)
{
	return 0;
}
static inline int p4d_clear_huge(p4d_t *p4d)
{
	return 0;
}
#endif /* !__PAGETABLE_P4D_FOLDED */

int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot);
int pmd_set_huge(pmd_t *pmd, phys_addr_t addr, pgprot_t prot);
int pud_clear_huge(pud_t *pud);
int pmd_clear_huge(pmd_t *pmd);
int p4d_free_pud_page(p4d_t *p4d, unsigned long addr);
int pud_free_pmd_page(pud_t *pud, unsigned long addr);
int pmd_free_pte_page(pmd_t *pmd, unsigned long addr);
#else	/* !CONFIG_HAVE_ARCH_HUGE_VMAP */
static inline int p4d_set_huge(p4d_t *p4d, phys_addr_t addr, pgprot_t prot)
{
	return 0;
}
static inline int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot)
{
	return 0;
}
static inline int pmd_set_huge(pmd_t *pmd, phys_addr_t addr, pgprot_t prot)
{
	return 0;
}
static inline int p4d_clear_huge(p4d_t *p4d)
{
	return 0;
}
static inline int pud_clear_huge(pud_t *pud)
{
	return 0;
}
static inline int pmd_clear_huge(pmd_t *pmd)
{
	return 0;
}
static inline int p4d_free_pud_page(p4d_t *p4d, unsigned long addr)
{
	return 0;
}
static inline int pud_free_pmd_page(pud_t *pud, unsigned long addr)
{
	return 0;
}
static inline int pmd_free_pte_page(pmd_t *pmd, unsigned long addr)
{
	return 0;
}
#endif	/* CONFIG_HAVE_ARCH_HUGE_VMAP */

#ifndef __HAVE_ARCH_FLUSH_PMD_TLB_RANGE
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
/*
 * ARCHes with special requirements for evicting THP backing TLB entries can
 * implement this. Otherwise also, it can help optimize normal TLB flush in
 * THP regime. stock flush_tlb_range() typically has optimization to nuke the
 * entire TLB TLB if flush span is greater than a threshold, which will
 * likely be true for a single huge page. Thus a single thp flush will
 * invalidate the entire TLB which is not desitable.
 * e.g. see arch/arc: flush_pmd_tlb_range
 */
#define flush_pmd_tlb_range(vma, addr, end)	flush_tlb_range(vma, addr, end)
#define flush_pud_tlb_range(vma, addr, end)	flush_tlb_range(vma, addr, end)
#else
#define flush_pmd_tlb_range(vma, addr, end)	BUILD_BUG()
#define flush_pud_tlb_range(vma, addr, end)	BUILD_BUG()
#endif
#endif

struct file;
int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
			unsigned long size, pgprot_t *vma_prot);

#ifndef CONFIG_X86_ESPFIX64
static inline void init_espfix_bsp(void) { }
#endif

extern void __init pgtable_cache_init(void);

#ifndef __HAVE_ARCH_PFN_MODIFY_ALLOWED
static inline bool pfn_modify_allowed(unsigned long pfn, pgprot_t prot)
{
	return true;
}

static inline bool arch_has_pfn_modify_check(void)
{
	return false;
}
#endif /* !_HAVE_ARCH_PFN_MODIFY_ALLOWED */

/*
 * Architecture PAGE_KERNEL_* fallbacks
 *
 * Some architectures don't define certain PAGE_KERNEL_* flags. This is either
 * because they really don't support them, or the port needs to be updated to
 * reflect the required functionality. Below are a set of relatively safe
 * fallbacks, as best effort, which we can count on in lieu of the architectures
 * not defining them on their own yet.
 */

#ifndef PAGE_KERNEL_RO
# define PAGE_KERNEL_RO PAGE_KERNEL
#endif

#ifndef PAGE_KERNEL_EXEC
# define PAGE_KERNEL_EXEC PAGE_KERNEL
#endif

/*
 * Page Table Modification bits for pgtbl_mod_mask.
 *
 * These are used by the p?d_alloc_track*() set of functions an in the generic
 * vmalloc/ioremap code to track at which page-table levels entries have been
 * modified. Based on that the code can better decide when vmalloc and ioremap
 * mapping changes need to be synchronized to other page-tables in the system.
 */
#define		__PGTBL_PGD_MODIFIED	0
#define		__PGTBL_P4D_MODIFIED	1
#define		__PGTBL_PUD_MODIFIED	2
#define		__PGTBL_PMD_MODIFIED	3
#define		__PGTBL_PTE_MODIFIED	4

#define		PGTBL_PGD_MODIFIED	BIT(__PGTBL_PGD_MODIFIED)
#define		PGTBL_P4D_MODIFIED	BIT(__PGTBL_P4D_MODIFIED)
#define		PGTBL_PUD_MODIFIED	BIT(__PGTBL_PUD_MODIFIED)
#define		PGTBL_PMD_MODIFIED	BIT(__PGTBL_PMD_MODIFIED)
#define		PGTBL_PTE_MODIFIED	BIT(__PGTBL_PTE_MODIFIED)

/* Page-Table Modification Mask */
typedef unsigned int pgtbl_mod_mask;

#endif /* !__ASSEMBLY__ */

#ifndef io_remap_pfn_range
#define io_remap_pfn_range remap_pfn_range
#endif

#ifndef has_transparent_hugepage
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
#define has_transparent_hugepage() 1
#else
#define has_transparent_hugepage() 0
#endif
#endif

/*
 * On some architectures it depends on the mm if the p4d/pud or pmd
 * layer of the page table hierarchy is folded or not.
 */
#ifndef mm_p4d_folded
#define mm_p4d_folded(mm)	__is_defined(__PAGETABLE_P4D_FOLDED)
#endif

#ifndef mm_pud_folded
#define mm_pud_folded(mm)	__is_defined(__PAGETABLE_PUD_FOLDED)
#endif

#ifndef mm_pmd_folded
#define mm_pmd_folded(mm)	__is_defined(__PAGETABLE_PMD_FOLDED)
#endif

/*
 * p?d_leaf() - true if this entry is a final mapping to a physical address.
 * This differs from p?d_huge() by the fact that they are always available (if
 * the architecture supports large pages at the appropriate level) even
 * if CONFIG_HUGETLB_PAGE is not defined.
 * Only meaningful when called on a valid entry.
 */
#ifndef pgd_leaf
#define pgd_leaf(x)	0
#endif
#ifndef p4d_leaf
#define p4d_leaf(x)	0
#endif
#ifndef pud_leaf
#define pud_leaf(x)	0
#endif
#ifndef pmd_leaf
#define pmd_leaf(x)	0
#endif

#endif /* _LINUX_PGTABLE_H */