summaryrefslogtreecommitdiff
path: root/kernel/power/snapshot.c
blob: 8e75a5a1e9b4e2a142e40c5246506eaba0893a9e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
/*
 * linux/kernel/power/snapshot.c
 *
 * This file provides system snapshot/restore functionality for swsusp.
 *
 * Copyright (C) 1998-2005 Pavel Machek <pavel@ucw.cz>
 * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
 *
 * This file is released under the GPLv2.
 *
 */

#include <linux/version.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/suspend.h>
#include <linux/delay.h>
#include <linux/bitops.h>
#include <linux/spinlock.h>
#include <linux/kernel.h>
#include <linux/pm.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/bootmem.h>
#include <linux/syscalls.h>
#include <linux/console.h>
#include <linux/highmem.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/compiler.h>
#include <linux/ktime.h>

#include <asm/uaccess.h>
#include <asm/mmu_context.h>
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
#include <asm/io.h>

#include "power.h"

static int swsusp_page_is_free(struct page *);
static void swsusp_set_page_forbidden(struct page *);
static void swsusp_unset_page_forbidden(struct page *);

/*
 * Number of bytes to reserve for memory allocations made by device drivers
 * from their ->freeze() and ->freeze_noirq() callbacks so that they don't
 * cause image creation to fail (tunable via /sys/power/reserved_size).
 */
unsigned long reserved_size;

void __init hibernate_reserved_size_init(void)
{
	reserved_size = SPARE_PAGES * PAGE_SIZE;
}

/*
 * Preferred image size in bytes (tunable via /sys/power/image_size).
 * When it is set to N, swsusp will do its best to ensure the image
 * size will not exceed N bytes, but if that is impossible, it will
 * try to create the smallest image possible.
 */
unsigned long image_size;

void __init hibernate_image_size_init(void)
{
	image_size = ((totalram_pages * 2) / 5) * PAGE_SIZE;
}

/* List of PBEs needed for restoring the pages that were allocated before
 * the suspend and included in the suspend image, but have also been
 * allocated by the "resume" kernel, so their contents cannot be written
 * directly to their "original" page frames.
 */
struct pbe *restore_pblist;

/* Pointer to an auxiliary buffer (1 page) */
static void *buffer;

/**
 *	@safe_needed - on resume, for storing the PBE list and the image,
 *	we can only use memory pages that do not conflict with the pages
 *	used before suspend.  The unsafe pages have PageNosaveFree set
 *	and we count them using unsafe_pages.
 *
 *	Each allocated image page is marked as PageNosave and PageNosaveFree
 *	so that swsusp_free() can release it.
 */

#define PG_ANY		0
#define PG_SAFE		1
#define PG_UNSAFE_CLEAR	1
#define PG_UNSAFE_KEEP	0

static unsigned int allocated_unsafe_pages;

static void *get_image_page(gfp_t gfp_mask, int safe_needed)
{
	void *res;

	res = (void *)get_zeroed_page(gfp_mask);
	if (safe_needed)
		while (res && swsusp_page_is_free(virt_to_page(res))) {
			/* The page is unsafe, mark it for swsusp_free() */
			swsusp_set_page_forbidden(virt_to_page(res));
			allocated_unsafe_pages++;
			res = (void *)get_zeroed_page(gfp_mask);
		}
	if (res) {
		swsusp_set_page_forbidden(virt_to_page(res));
		swsusp_set_page_free(virt_to_page(res));
	}
	return res;
}

unsigned long get_safe_page(gfp_t gfp_mask)
{
	return (unsigned long)get_image_page(gfp_mask, PG_SAFE);
}

static struct page *alloc_image_page(gfp_t gfp_mask)
{
	struct page *page;

	page = alloc_page(gfp_mask);
	if (page) {
		swsusp_set_page_forbidden(page);
		swsusp_set_page_free(page);
	}
	return page;
}

/**
 *	free_image_page - free page represented by @addr, allocated with
 *	get_image_page (page flags set by it must be cleared)
 */

static inline void free_image_page(void *addr, int clear_nosave_free)
{
	struct page *page;

	BUG_ON(!virt_addr_valid(addr));

	page = virt_to_page(addr);

	swsusp_unset_page_forbidden(page);
	if (clear_nosave_free)
		swsusp_unset_page_free(page);

	__free_page(page);
}

/* struct linked_page is used to build chains of pages */

#define LINKED_PAGE_DATA_SIZE	(PAGE_SIZE - sizeof(void *))

struct linked_page {
	struct linked_page *next;
	char data[LINKED_PAGE_DATA_SIZE];
} __packed;

static inline void
free_list_of_pages(struct linked_page *list, int clear_page_nosave)
{
	while (list) {
		struct linked_page *lp = list->next;

		free_image_page(list, clear_page_nosave);
		list = lp;
	}
}

/**
  *	struct chain_allocator is used for allocating small objects out of
  *	a linked list of pages called 'the chain'.
  *
  *	The chain grows each time when there is no room for a new object in
  *	the current page.  The allocated objects cannot be freed individually.
  *	It is only possible to free them all at once, by freeing the entire
  *	chain.
  *
  *	NOTE: The chain allocator may be inefficient if the allocated objects
  *	are not much smaller than PAGE_SIZE.
  */

struct chain_allocator {
	struct linked_page *chain;	/* the chain */
	unsigned int used_space;	/* total size of objects allocated out
					 * of the current page
					 */
	gfp_t gfp_mask;		/* mask for allocating pages */
	int safe_needed;	/* if set, only "safe" pages are allocated */
};

static void
chain_init(struct chain_allocator *ca, gfp_t gfp_mask, int safe_needed)
{
	ca->chain = NULL;
	ca->used_space = LINKED_PAGE_DATA_SIZE;
	ca->gfp_mask = gfp_mask;
	ca->safe_needed = safe_needed;
}

static void *chain_alloc(struct chain_allocator *ca, unsigned int size)
{
	void *ret;

	if (LINKED_PAGE_DATA_SIZE - ca->used_space < size) {
		struct linked_page *lp;

		lp = get_image_page(ca->gfp_mask, ca->safe_needed);
		if (!lp)
			return NULL;

		lp->next = ca->chain;
		ca->chain = lp;
		ca->used_space = 0;
	}
	ret = ca->chain->data + ca->used_space;
	ca->used_space += size;
	return ret;
}

/**
 *	Data types related to memory bitmaps.
 *
 *	Memory bitmap is a structure consiting of many linked lists of
 *	objects.  The main list's elements are of type struct zone_bitmap
 *	and each of them corresonds to one zone.  For each zone bitmap
 *	object there is a list of objects of type struct bm_block that
 *	represent each blocks of bitmap in which information is stored.
 *
 *	struct memory_bitmap contains a pointer to the main list of zone
 *	bitmap objects, a struct bm_position used for browsing the bitmap,
 *	and a pointer to the list of pages used for allocating all of the
 *	zone bitmap objects and bitmap block objects.
 *
 *	NOTE: It has to be possible to lay out the bitmap in memory
 *	using only allocations of order 0.  Additionally, the bitmap is
 *	designed to work with arbitrary number of zones (this is over the
 *	top for now, but let's avoid making unnecessary assumptions ;-).
 *
 *	struct zone_bitmap contains a pointer to a list of bitmap block
 *	objects and a pointer to the bitmap block object that has been
 *	most recently used for setting bits.  Additionally, it contains the
 *	pfns that correspond to the start and end of the represented zone.
 *
 *	struct bm_block contains a pointer to the memory page in which
 *	information is stored (in the form of a block of bitmap)
 *	It also contains the pfns that correspond to the start and end of
 *	the represented memory area.
 *
 *	The memory bitmap is organized as a radix tree to guarantee fast random
 *	access to the bits. There is one radix tree for each zone (as returned
 *	from create_mem_extents).
 *
 *	One radix tree is represented by one struct mem_zone_bm_rtree. There are
 *	two linked lists for the nodes of the tree, one for the inner nodes and
 *	one for the leave nodes. The linked leave nodes are used for fast linear
 *	access of the memory bitmap.
 *
 *	The struct rtree_node represents one node of the radix tree.
 */

#define BM_END_OF_MAP	(~0UL)

#define BM_BITS_PER_BLOCK	(PAGE_SIZE * BITS_PER_BYTE)
#define BM_BLOCK_SHIFT		(PAGE_SHIFT + 3)
#define BM_BLOCK_MASK		((1UL << BM_BLOCK_SHIFT) - 1)

/*
 * struct rtree_node is a wrapper struct to link the nodes
 * of the rtree together for easy linear iteration over
 * bits and easy freeing
 */
struct rtree_node {
	struct list_head list;
	unsigned long *data;
};

/*
 * struct mem_zone_bm_rtree represents a bitmap used for one
 * populated memory zone.
 */
struct mem_zone_bm_rtree {
	struct list_head list;		/* Link Zones together         */
	struct list_head nodes;		/* Radix Tree inner nodes      */
	struct list_head leaves;	/* Radix Tree leaves           */
	unsigned long start_pfn;	/* Zone start page frame       */
	unsigned long end_pfn;		/* Zone end page frame + 1     */
	struct rtree_node *rtree;	/* Radix Tree Root             */
	int levels;			/* Number of Radix Tree Levels */
	unsigned int blocks;		/* Number of Bitmap Blocks     */
};

/* strcut bm_position is used for browsing memory bitmaps */

struct bm_position {
	struct mem_zone_bm_rtree *zone;
	struct rtree_node *node;
	unsigned long node_pfn;
	int node_bit;
};

struct memory_bitmap {
	struct list_head zones;
	struct linked_page *p_list;	/* list of pages used to store zone
					 * bitmap objects and bitmap block
					 * objects
					 */
	struct bm_position cur;	/* most recently used bit position */
};

/* Functions that operate on memory bitmaps */

#define BM_ENTRIES_PER_LEVEL	(PAGE_SIZE / sizeof(unsigned long))
#if BITS_PER_LONG == 32
#define BM_RTREE_LEVEL_SHIFT	(PAGE_SHIFT - 2)
#else
#define BM_RTREE_LEVEL_SHIFT	(PAGE_SHIFT - 3)
#endif
#define BM_RTREE_LEVEL_MASK	((1UL << BM_RTREE_LEVEL_SHIFT) - 1)

/*
 *	alloc_rtree_node - Allocate a new node and add it to the radix tree.
 *
 *	This function is used to allocate inner nodes as well as the
 *	leave nodes of the radix tree. It also adds the node to the
 *	corresponding linked list passed in by the *list parameter.
 */
static struct rtree_node *alloc_rtree_node(gfp_t gfp_mask, int safe_needed,
					   struct chain_allocator *ca,
					   struct list_head *list)
{
	struct rtree_node *node;

	node = chain_alloc(ca, sizeof(struct rtree_node));
	if (!node)
		return NULL;

	node->data = get_image_page(gfp_mask, safe_needed);
	if (!node->data)
		return NULL;

	list_add_tail(&node->list, list);

	return node;
}

/*
 *	add_rtree_block - Add a new leave node to the radix tree
 *
 *	The leave nodes need to be allocated in order to keep the leaves
 *	linked list in order. This is guaranteed by the zone->blocks
 *	counter.
 */
static int add_rtree_block(struct mem_zone_bm_rtree *zone, gfp_t gfp_mask,
			   int safe_needed, struct chain_allocator *ca)
{
	struct rtree_node *node, *block, **dst;
	unsigned int levels_needed, block_nr;
	int i;

	block_nr = zone->blocks;
	levels_needed = 0;

	/* How many levels do we need for this block nr? */
	while (block_nr) {
		levels_needed += 1;
		block_nr >>= BM_RTREE_LEVEL_SHIFT;
	}

	/* Make sure the rtree has enough levels */
	for (i = zone->levels; i < levels_needed; i++) {
		node = alloc_rtree_node(gfp_mask, safe_needed, ca,
					&zone->nodes);
		if (!node)
			return -ENOMEM;

		node->data[0] = (unsigned long)zone->rtree;
		zone->rtree = node;
		zone->levels += 1;
	}

	/* Allocate new block */
	block = alloc_rtree_node(gfp_mask, safe_needed, ca, &zone->leaves);
	if (!block)
		return -ENOMEM;

	/* Now walk the rtree to insert the block */
	node = zone->rtree;
	dst = &zone->rtree;
	block_nr = zone->blocks;
	for (i = zone->levels; i > 0; i--) {
		int index;

		if (!node) {
			node = alloc_rtree_node(gfp_mask, safe_needed, ca,
						&zone->nodes);
			if (!node)
				return -ENOMEM;
			*dst = node;
		}

		index = block_nr >> ((i - 1) * BM_RTREE_LEVEL_SHIFT);
		index &= BM_RTREE_LEVEL_MASK;
		dst = (struct rtree_node **)&((*dst)->data[index]);
		node = *dst;
	}

	zone->blocks += 1;
	*dst = block;

	return 0;
}

static void free_zone_bm_rtree(struct mem_zone_bm_rtree *zone,
			       int clear_nosave_free);

/*
 *	create_zone_bm_rtree - create a radix tree for one zone
 *
 *	Allocated the mem_zone_bm_rtree structure and initializes it.
 *	This function also allocated and builds the radix tree for the
 *	zone.
 */
static struct mem_zone_bm_rtree *
create_zone_bm_rtree(gfp_t gfp_mask, int safe_needed,
		     struct chain_allocator *ca,
		     unsigned long start, unsigned long end)
{
	struct mem_zone_bm_rtree *zone;
	unsigned int i, nr_blocks;
	unsigned long pages;

	pages = end - start;
	zone  = chain_alloc(ca, sizeof(struct mem_zone_bm_rtree));
	if (!zone)
		return NULL;

	INIT_LIST_HEAD(&zone->nodes);
	INIT_LIST_HEAD(&zone->leaves);
	zone->start_pfn = start;
	zone->end_pfn = end;
	nr_blocks = DIV_ROUND_UP(pages, BM_BITS_PER_BLOCK);

	for (i = 0; i < nr_blocks; i++) {
		if (add_rtree_block(zone, gfp_mask, safe_needed, ca)) {
			free_zone_bm_rtree(zone, PG_UNSAFE_CLEAR);
			return NULL;
		}
	}

	return zone;
}

/*
 *	free_zone_bm_rtree - Free the memory of the radix tree
 *
 *	Free all node pages of the radix tree. The mem_zone_bm_rtree
 *	structure itself is not freed here nor are the rtree_node
 *	structs.
 */
static void free_zone_bm_rtree(struct mem_zone_bm_rtree *zone,
			       int clear_nosave_free)
{
	struct rtree_node *node;

	list_for_each_entry(node, &zone->nodes, list)
		free_image_page(node->data, clear_nosave_free);

	list_for_each_entry(node, &zone->leaves, list)
		free_image_page(node->data, clear_nosave_free);
}

static void memory_bm_position_reset(struct memory_bitmap *bm)
{
	bm->cur.zone = list_entry(bm->zones.next, struct mem_zone_bm_rtree,
				  list);
	bm->cur.node = list_entry(bm->cur.zone->leaves.next,
				  struct rtree_node, list);
	bm->cur.node_pfn = 0;
	bm->cur.node_bit = 0;
}

static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free);

struct mem_extent {
	struct list_head hook;
	unsigned long start;
	unsigned long end;
};

/**
 *	free_mem_extents - free a list of memory extents
 *	@list - list of extents to empty
 */
static void free_mem_extents(struct list_head *list)
{
	struct mem_extent *ext, *aux;

	list_for_each_entry_safe(ext, aux, list, hook) {
		list_del(&ext->hook);
		kfree(ext);
	}
}

/**
 *	create_mem_extents - create a list of memory extents representing
 *	                     contiguous ranges of PFNs
 *	@list - list to put the extents into
 *	@gfp_mask - mask to use for memory allocations
 */
static int create_mem_extents(struct list_head *list, gfp_t gfp_mask)
{
	struct zone *zone;

	INIT_LIST_HEAD(list);

	for_each_populated_zone(zone) {
		unsigned long zone_start, zone_end;
		struct mem_extent *ext, *cur, *aux;

		zone_start = zone->zone_start_pfn;
		zone_end = zone_end_pfn(zone);

		list_for_each_entry(ext, list, hook)
			if (zone_start <= ext->end)
				break;

		if (&ext->hook == list || zone_end < ext->start) {
			/* New extent is necessary */
			struct mem_extent *new_ext;

			new_ext = kzalloc(sizeof(struct mem_extent), gfp_mask);
			if (!new_ext) {
				free_mem_extents(list);
				return -ENOMEM;
			}
			new_ext->start = zone_start;
			new_ext->end = zone_end;
			list_add_tail(&new_ext->hook, &ext->hook);
			continue;
		}

		/* Merge this zone's range of PFNs with the existing one */
		if (zone_start < ext->start)
			ext->start = zone_start;
		if (zone_end > ext->end)
			ext->end = zone_end;

		/* More merging may be possible */
		cur = ext;
		list_for_each_entry_safe_continue(cur, aux, list, hook) {
			if (zone_end < cur->start)
				break;
			if (zone_end < cur->end)
				ext->end = cur->end;
			list_del(&cur->hook);
			kfree(cur);
		}
	}

	return 0;
}

/**
  *	memory_bm_create - allocate memory for a memory bitmap
  */
static int
memory_bm_create(struct memory_bitmap *bm, gfp_t gfp_mask, int safe_needed)
{
	struct chain_allocator ca;
	struct list_head mem_extents;
	struct mem_extent *ext;
	int error;

	chain_init(&ca, gfp_mask, safe_needed);
	INIT_LIST_HEAD(&bm->zones);

	error = create_mem_extents(&mem_extents, gfp_mask);
	if (error)
		return error;

	list_for_each_entry(ext, &mem_extents, hook) {
		struct mem_zone_bm_rtree *zone;

		zone = create_zone_bm_rtree(gfp_mask, safe_needed, &ca,
					    ext->start, ext->end);
		if (!zone) {
			error = -ENOMEM;
			goto Error;
		}
		list_add_tail(&zone->list, &bm->zones);
	}

	bm->p_list = ca.chain;
	memory_bm_position_reset(bm);
 Exit:
	free_mem_extents(&mem_extents);
	return error;

 Error:
	bm->p_list = ca.chain;
	memory_bm_free(bm, PG_UNSAFE_CLEAR);
	goto Exit;
}

/**
  *	memory_bm_free - free memory occupied by the memory bitmap @bm
  */
static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free)
{
	struct mem_zone_bm_rtree *zone;

	list_for_each_entry(zone, &bm->zones, list)
		free_zone_bm_rtree(zone, clear_nosave_free);

	free_list_of_pages(bm->p_list, clear_nosave_free);

	INIT_LIST_HEAD(&bm->zones);
}

/**
 *	memory_bm_find_bit - Find the bit for pfn in the memory
 *			     bitmap
 *
 *	Find the bit in the bitmap @bm that corresponds to given pfn.
 *	The cur.zone, cur.block and cur.node_pfn member of @bm are
 *	updated.
 *	It walks the radix tree to find the page which contains the bit for
 *	pfn and returns the bit position in **addr and *bit_nr.
 */
static int memory_bm_find_bit(struct memory_bitmap *bm, unsigned long pfn,
			      void **addr, unsigned int *bit_nr)
{
	struct mem_zone_bm_rtree *curr, *zone;
	struct rtree_node *node;
	int i, block_nr;

	zone = bm->cur.zone;

	if (pfn >= zone->start_pfn && pfn < zone->end_pfn)
		goto zone_found;

	zone = NULL;

	/* Find the right zone */
	list_for_each_entry(curr, &bm->zones, list) {
		if (pfn >= curr->start_pfn && pfn < curr->end_pfn) {
			zone = curr;
			break;
		}
	}

	if (!zone)
		return -EFAULT;

zone_found:
	/*
	 * We have a zone. Now walk the radix tree to find the leave
	 * node for our pfn.
	 */

	node = bm->cur.node;
	if (((pfn - zone->start_pfn) & ~BM_BLOCK_MASK) == bm->cur.node_pfn)
		goto node_found;

	node      = zone->rtree;
	block_nr  = (pfn - zone->start_pfn) >> BM_BLOCK_SHIFT;

	for (i = zone->levels; i > 0; i--) {
		int index;

		index = block_nr >> ((i - 1) * BM_RTREE_LEVEL_SHIFT);
		index &= BM_RTREE_LEVEL_MASK;
		BUG_ON(node->data[index] == 0);
		node = (struct rtree_node *)node->data[index];
	}

node_found:
	/* Update last position */
	bm->cur.zone = zone;
	bm->cur.node = node;
	bm->cur.node_pfn = (pfn - zone->start_pfn) & ~BM_BLOCK_MASK;

	/* Set return values */
	*addr = node->data;
	*bit_nr = (pfn - zone->start_pfn) & BM_BLOCK_MASK;

	return 0;
}

static void memory_bm_set_bit(struct memory_bitmap *bm, unsigned long pfn)
{
	void *addr;
	unsigned int bit;
	int error;

	error = memory_bm_find_bit(bm, pfn, &addr, &bit);
	BUG_ON(error);
	set_bit(bit, addr);
}

static int mem_bm_set_bit_check(struct memory_bitmap *bm, unsigned long pfn)
{
	void *addr;
	unsigned int bit;
	int error;

	error = memory_bm_find_bit(bm, pfn, &addr, &bit);
	if (!error)
		set_bit(bit, addr);

	return error;
}

static void memory_bm_clear_bit(struct memory_bitmap *bm, unsigned long pfn)
{
	void *addr;
	unsigned int bit;
	int error;

	error = memory_bm_find_bit(bm, pfn, &addr, &bit);
	BUG_ON(error);
	clear_bit(bit, addr);
}

static void memory_bm_clear_current(struct memory_bitmap *bm)
{
	int bit;

	bit = max(bm->cur.node_bit - 1, 0);
	clear_bit(bit, bm->cur.node->data);
}

static int memory_bm_test_bit(struct memory_bitmap *bm, unsigned long pfn)
{
	void *addr;
	unsigned int bit;
	int error;

	error = memory_bm_find_bit(bm, pfn, &addr, &bit);
	BUG_ON(error);
	return test_bit(bit, addr);
}

static bool memory_bm_pfn_present(struct memory_bitmap *bm, unsigned long pfn)
{
	void *addr;
	unsigned int bit;

	return !memory_bm_find_bit(bm, pfn, &addr, &bit);
}

/*
 *	rtree_next_node - Jumps to the next leave node
 *
 *	Sets the position to the beginning of the next node in the
 *	memory bitmap. This is either the next node in the current
 *	zone's radix tree or the first node in the radix tree of the
 *	next zone.
 *
 *	Returns true if there is a next node, false otherwise.
 */
static bool rtree_next_node(struct memory_bitmap *bm)
{
	bm->cur.node = list_entry(bm->cur.node->list.next,
				  struct rtree_node, list);
	if (&bm->cur.node->list != &bm->cur.zone->leaves) {
		bm->cur.node_pfn += BM_BITS_PER_BLOCK;
		bm->cur.node_bit  = 0;
		touch_softlockup_watchdog();
		return true;
	}

	/* No more nodes, goto next zone */
	bm->cur.zone = list_entry(bm->cur.zone->list.next,
				  struct mem_zone_bm_rtree, list);
	if (&bm->cur.zone->list != &bm->zones) {
		bm->cur.node = list_entry(bm->cur.zone->leaves.next,
					  struct rtree_node, list);
		bm->cur.node_pfn = 0;
		bm->cur.node_bit = 0;
		return true;
	}

	/* No more zones */
	return false;
}

/**
 *	memory_bm_rtree_next_pfn - Find the next set bit in the bitmap @bm
 *
 *	Starting from the last returned position this function searches
 *	for the next set bit in the memory bitmap and returns its
 *	number. If no more bit is set BM_END_OF_MAP is returned.
 *
 *	It is required to run memory_bm_position_reset() before the
 *	first call to this function.
 */
static unsigned long memory_bm_next_pfn(struct memory_bitmap *bm)
{
	unsigned long bits, pfn, pages;
	int bit;

	do {
		pages	  = bm->cur.zone->end_pfn - bm->cur.zone->start_pfn;
		bits      = min(pages - bm->cur.node_pfn, BM_BITS_PER_BLOCK);
		bit	  = find_next_bit(bm->cur.node->data, bits,
					  bm->cur.node_bit);
		if (bit < bits) {
			pfn = bm->cur.zone->start_pfn + bm->cur.node_pfn + bit;
			bm->cur.node_bit = bit + 1;
			return pfn;
		}
	} while (rtree_next_node(bm));

	return BM_END_OF_MAP;
}

/**
 *	This structure represents a range of page frames the contents of which
 *	should not be saved during the suspend.
 */

struct nosave_region {
	struct list_head list;
	unsigned long start_pfn;
	unsigned long end_pfn;
};

static LIST_HEAD(nosave_regions);

/**
 *	register_nosave_region - register a range of page frames the contents
 *	of which should not be saved during the suspend (to be used in the early
 *	initialization code)
 */

void __init
__register_nosave_region(unsigned long start_pfn, unsigned long end_pfn,
			 int use_kmalloc)
{
	struct nosave_region *region;

	if (start_pfn >= end_pfn)
		return;

	if (!list_empty(&nosave_regions)) {
		/* Try to extend the previous region (they should be sorted) */
		region = list_entry(nosave_regions.prev,
					struct nosave_region, list);
		if (region->end_pfn == start_pfn) {
			region->end_pfn = end_pfn;
			goto Report;
		}
	}
	if (use_kmalloc) {
		/* during init, this shouldn't fail */
		region = kmalloc(sizeof(struct nosave_region), GFP_KERNEL);
		BUG_ON(!region);
	} else
		/* This allocation cannot fail */
		region = memblock_virt_alloc(sizeof(struct nosave_region), 0);
	region->start_pfn = start_pfn;
	region->end_pfn = end_pfn;
	list_add_tail(&region->list, &nosave_regions);
 Report:
	printk(KERN_INFO "PM: Registered nosave memory: [mem %#010llx-%#010llx]\n",
		(unsigned long long) start_pfn << PAGE_SHIFT,
		((unsigned long long) end_pfn << PAGE_SHIFT) - 1);
}

/*
 * Set bits in this map correspond to the page frames the contents of which
 * should not be saved during the suspend.
 */
static struct memory_bitmap *forbidden_pages_map;

/* Set bits in this map correspond to free page frames. */
static struct memory_bitmap *free_pages_map;

/*
 * Each page frame allocated for creating the image is marked by setting the
 * corresponding bits in forbidden_pages_map and free_pages_map simultaneously
 */

void swsusp_set_page_free(struct page *page)
{
	if (free_pages_map)
		memory_bm_set_bit(free_pages_map, page_to_pfn(page));
}

static int swsusp_page_is_free(struct page *page)
{
	return free_pages_map ?
		memory_bm_test_bit(free_pages_map, page_to_pfn(page)) : 0;
}

void swsusp_unset_page_free(struct page *page)
{
	if (free_pages_map)
		memory_bm_clear_bit(free_pages_map, page_to_pfn(page));
}

static void swsusp_set_page_forbidden(struct page *page)
{
	if (forbidden_pages_map)
		memory_bm_set_bit(forbidden_pages_map, page_to_pfn(page));
}

int swsusp_page_is_forbidden(struct page *page)
{
	return forbidden_pages_map ?
		memory_bm_test_bit(forbidden_pages_map, page_to_pfn(page)) : 0;
}

static void swsusp_unset_page_forbidden(struct page *page)
{
	if (forbidden_pages_map)
		memory_bm_clear_bit(forbidden_pages_map, page_to_pfn(page));
}

/**
 *	mark_nosave_pages - set bits corresponding to the page frames the
 *	contents of which should not be saved in a given bitmap.
 */

static void mark_nosave_pages(struct memory_bitmap *bm)
{
	struct nosave_region *region;

	if (list_empty(&nosave_regions))
		return;

	list_for_each_entry(region, &nosave_regions, list) {
		unsigned long pfn;

		pr_debug("PM: Marking nosave pages: [mem %#010llx-%#010llx]\n",
			 (unsigned long long) region->start_pfn << PAGE_SHIFT,
			 ((unsigned long long) region->end_pfn << PAGE_SHIFT)
				- 1);

		for (pfn = region->start_pfn; pfn < region->end_pfn; pfn++)
			if (pfn_valid(pfn)) {
				/*
				 * It is safe to ignore the result of
				 * mem_bm_set_bit_check() here, since we won't
				 * touch the PFNs for which the error is
				 * returned anyway.
				 */
				mem_bm_set_bit_check(bm, pfn);
			}
	}
}

static bool is_nosave_page(unsigned long pfn)
{
	struct nosave_region *region;

	list_for_each_entry(region, &nosave_regions, list) {
		if (pfn >= region->start_pfn && pfn < region->end_pfn) {
			pr_err("PM: %#010llx in e820 nosave region: "
			       "[mem %#010llx-%#010llx]\n",
			       (unsigned long long) pfn << PAGE_SHIFT,
			       (unsigned long long) region->start_pfn << PAGE_SHIFT,
			       ((unsigned long long) region->end_pfn << PAGE_SHIFT)
					- 1);
			return true;
		}
	}

	return false;
}

/**
 *	create_basic_memory_bitmaps - create bitmaps needed for marking page
 *	frames that should not be saved and free page frames.  The pointers
 *	forbidden_pages_map and free_pages_map are only modified if everything
 *	goes well, because we don't want the bits to be used before both bitmaps
 *	are set up.
 */

int create_basic_memory_bitmaps(void)
{
	struct memory_bitmap *bm1, *bm2;
	int error = 0;

	if (forbidden_pages_map && free_pages_map)
		return 0;
	else
		BUG_ON(forbidden_pages_map || free_pages_map);

	bm1 = kzalloc(sizeof(struct memory_bitmap), GFP_KERNEL);
	if (!bm1)
		return -ENOMEM;

	error = memory_bm_create(bm1, GFP_KERNEL, PG_ANY);
	if (error)
		goto Free_first_object;

	bm2 = kzalloc(sizeof(struct memory_bitmap), GFP_KERNEL);
	if (!bm2)
		goto Free_first_bitmap;

	error = memory_bm_create(bm2, GFP_KERNEL, PG_ANY);
	if (error)
		goto Free_second_object;

	forbidden_pages_map = bm1;
	free_pages_map = bm2;
	mark_nosave_pages(forbidden_pages_map);

	pr_debug("PM: Basic memory bitmaps created\n");

	return 0;

 Free_second_object:
	kfree(bm2);
 Free_first_bitmap:
 	memory_bm_free(bm1, PG_UNSAFE_CLEAR);
 Free_first_object:
	kfree(bm1);
	return -ENOMEM;
}

/**
 *	free_basic_memory_bitmaps - free memory bitmaps allocated by
 *	create_basic_memory_bitmaps().  The auxiliary pointers are necessary
 *	so that the bitmaps themselves are not referred to while they are being
 *	freed.
 */

void free_basic_memory_bitmaps(void)
{
	struct memory_bitmap *bm1, *bm2;

	if (WARN_ON(!(forbidden_pages_map && free_pages_map)))
		return;

	bm1 = forbidden_pages_map;
	bm2 = free_pages_map;
	forbidden_pages_map = NULL;
	free_pages_map = NULL;
	memory_bm_free(bm1, PG_UNSAFE_CLEAR);
	kfree(bm1);
	memory_bm_free(bm2, PG_UNSAFE_CLEAR);
	kfree(bm2);

	pr_debug("PM: Basic memory bitmaps freed\n");
}

/**
 *	snapshot_additional_pages - estimate the number of additional pages
 *	be needed for setting up the suspend image data structures for given
 *	zone (usually the returned value is greater than the exact number)
 */

unsigned int snapshot_additional_pages(struct zone *zone)
{
	unsigned int rtree, nodes;

	rtree = nodes = DIV_ROUND_UP(zone->spanned_pages, BM_BITS_PER_BLOCK);
	rtree += DIV_ROUND_UP(rtree * sizeof(struct rtree_node),
			      LINKED_PAGE_DATA_SIZE);
	while (nodes > 1) {
		nodes = DIV_ROUND_UP(nodes, BM_ENTRIES_PER_LEVEL);
		rtree += nodes;
	}

	return 2 * rtree;
}

#ifdef CONFIG_HIGHMEM
/**
 *	count_free_highmem_pages - compute the total number of free highmem
 *	pages, system-wide.
 */

static unsigned int count_free_highmem_pages(void)
{
	struct zone *zone;
	unsigned int cnt = 0;

	for_each_populated_zone(zone)
		if (is_highmem(zone))
			cnt += zone_page_state(zone, NR_FREE_PAGES);

	return cnt;
}

/**
 *	saveable_highmem_page - Determine whether a highmem page should be
 *	included in the suspend image.
 *
 *	We should save the page if it isn't Nosave or NosaveFree, or Reserved,
 *	and it isn't a part of a free chunk of pages.
 */
static struct page *saveable_highmem_page(struct zone *zone, unsigned long pfn)
{
	struct page *page;

	if (!pfn_valid(pfn))
		return NULL;

	page = pfn_to_page(pfn);
	if (page_zone(page) != zone)
		return NULL;

	BUG_ON(!PageHighMem(page));

	if (swsusp_page_is_forbidden(page) ||  swsusp_page_is_free(page) ||
	    PageReserved(page))
		return NULL;

	if (page_is_guard(page))
		return NULL;

	return page;
}

/**
 *	count_highmem_pages - compute the total number of saveable highmem
 *	pages.
 */

static unsigned int count_highmem_pages(void)
{
	struct zone *zone;
	unsigned int n = 0;

	for_each_populated_zone(zone) {
		unsigned long pfn, max_zone_pfn;

		if (!is_highmem(zone))
			continue;

		mark_free_pages(zone);
		max_zone_pfn = zone_end_pfn(zone);
		for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
			if (saveable_highmem_page(zone, pfn))
				n++;
	}
	return n;
}
#else
static inline void *saveable_highmem_page(struct zone *z, unsigned long p)
{
	return NULL;
}
#endif /* CONFIG_HIGHMEM */

/**
 *	saveable_page - Determine whether a non-highmem page should be included
 *	in the suspend image.
 *
 *	We should save the page if it isn't Nosave, and is not in the range
 *	of pages statically defined as 'unsaveable', and it isn't a part of
 *	a free chunk of pages.
 */
static struct page *saveable_page(struct zone *zone, unsigned long pfn)
{
	struct page *page;

	if (!pfn_valid(pfn))
		return NULL;

	page = pfn_to_page(pfn);
	if (page_zone(page) != zone)
		return NULL;

	BUG_ON(PageHighMem(page));

	if (swsusp_page_is_forbidden(page) || swsusp_page_is_free(page))
		return NULL;

	if (PageReserved(page)
	    && (!kernel_page_present(page) || pfn_is_nosave(pfn)))
		return NULL;

	if (page_is_guard(page))
		return NULL;

	return page;
}

/**
 *	count_data_pages - compute the total number of saveable non-highmem
 *	pages.
 */

static unsigned int count_data_pages(void)
{
	struct zone *zone;
	unsigned long pfn, max_zone_pfn;
	unsigned int n = 0;

	for_each_populated_zone(zone) {
		if (is_highmem(zone))
			continue;

		mark_free_pages(zone);
		max_zone_pfn = zone_end_pfn(zone);
		for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
			if (saveable_page(zone, pfn))
				n++;
	}
	return n;
}

/* This is needed, because copy_page and memcpy are not usable for copying
 * task structs.
 */
static inline void do_copy_page(long *dst, long *src)
{
	int n;

	for (n = PAGE_SIZE / sizeof(long); n; n--)
		*dst++ = *src++;
}


/**
 *	safe_copy_page - check if the page we are going to copy is marked as
 *		present in the kernel page tables (this always is the case if
 *		CONFIG_DEBUG_PAGEALLOC is not set and in that case
 *		kernel_page_present() always returns 'true').
 */
static void safe_copy_page(void *dst, struct page *s_page)
{
	if (kernel_page_present(s_page)) {
		do_copy_page(dst, page_address(s_page));
	} else {
		kernel_map_pages(s_page, 1, 1);
		do_copy_page(dst, page_address(s_page));
		kernel_map_pages(s_page, 1, 0);
	}
}


#ifdef CONFIG_HIGHMEM
static inline struct page *
page_is_saveable(struct zone *zone, unsigned long pfn)
{
	return is_highmem(zone) ?
		saveable_highmem_page(zone, pfn) : saveable_page(zone, pfn);
}

static void copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
{
	struct page *s_page, *d_page;
	void *src, *dst;

	s_page = pfn_to_page(src_pfn);
	d_page = pfn_to_page(dst_pfn);
	if (PageHighMem(s_page)) {
		src = kmap_atomic(s_page);
		dst = kmap_atomic(d_page);
		do_copy_page(dst, src);
		kunmap_atomic(dst);
		kunmap_atomic(src);
	} else {
		if (PageHighMem(d_page)) {
			/* Page pointed to by src may contain some kernel
			 * data modified by kmap_atomic()
			 */
			safe_copy_page(buffer, s_page);
			dst = kmap_atomic(d_page);
			copy_page(dst, buffer);
			kunmap_atomic(dst);
		} else {
			safe_copy_page(page_address(d_page), s_page);
		}
	}
}
#else
#define page_is_saveable(zone, pfn)	saveable_page(zone, pfn)

static inline void copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
{
	safe_copy_page(page_address(pfn_to_page(dst_pfn)),
				pfn_to_page(src_pfn));
}
#endif /* CONFIG_HIGHMEM */

static void
copy_data_pages(struct memory_bitmap *copy_bm, struct memory_bitmap *orig_bm)
{
	struct zone *zone;
	unsigned long pfn;

	for_each_populated_zone(zone) {
		unsigned long max_zone_pfn;

		mark_free_pages(zone);
		max_zone_pfn = zone_end_pfn(zone);
		for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
			if (page_is_saveable(zone, pfn))
				memory_bm_set_bit(orig_bm, pfn);
	}
	memory_bm_position_reset(orig_bm);
	memory_bm_position_reset(copy_bm);
	for(;;) {
		pfn = memory_bm_next_pfn(orig_bm);
		if (unlikely(pfn == BM_END_OF_MAP))
			break;
		copy_data_page(memory_bm_next_pfn(copy_bm), pfn);
	}
}

/* Total number of image pages */
static unsigned int nr_copy_pages;
/* Number of pages needed for saving the original pfns of the image pages */
static unsigned int nr_meta_pages;
/*
 * Numbers of normal and highmem page frames allocated for hibernation image
 * before suspending devices.
 */
unsigned int alloc_normal, alloc_highmem;
/*
 * Memory bitmap used for marking saveable pages (during hibernation) or
 * hibernation image pages (during restore)
 */
static struct memory_bitmap orig_bm;
/*
 * Memory bitmap used during hibernation for marking allocated page frames that
 * will contain copies of saveable pages.  During restore it is initially used
 * for marking hibernation image pages, but then the set bits from it are
 * duplicated in @orig_bm and it is released.  On highmem systems it is next
 * used for marking "safe" highmem pages, but it has to be reinitialized for
 * this purpose.
 */
static struct memory_bitmap copy_bm;

/**
 *	swsusp_free - free pages allocated for the suspend.
 *
 *	Suspend pages are alocated before the atomic copy is made, so we
 *	need to release them after the resume.
 */

void swsusp_free(void)
{
	unsigned long fb_pfn, fr_pfn;

	if (!forbidden_pages_map || !free_pages_map)
		goto out;

	memory_bm_position_reset(forbidden_pages_map);
	memory_bm_position_reset(free_pages_map);

loop:
	fr_pfn = memory_bm_next_pfn(free_pages_map);
	fb_pfn = memory_bm_next_pfn(forbidden_pages_map);

	/*
	 * Find the next bit set in both bitmaps. This is guaranteed to
	 * terminate when fb_pfn == fr_pfn == BM_END_OF_MAP.
	 */
	do {
		if (fb_pfn < fr_pfn)
			fb_pfn = memory_bm_next_pfn(forbidden_pages_map);
		if (fr_pfn < fb_pfn)
			fr_pfn = memory_bm_next_pfn(free_pages_map);
	} while (fb_pfn != fr_pfn);

	if (fr_pfn != BM_END_OF_MAP && pfn_valid(fr_pfn)) {
		struct page *page = pfn_to_page(fr_pfn);

		memory_bm_clear_current(forbidden_pages_map);
		memory_bm_clear_current(free_pages_map);
		__free_page(page);
		goto loop;
	}

out:
	nr_copy_pages = 0;
	nr_meta_pages = 0;
	restore_pblist = NULL;
	buffer = NULL;
	alloc_normal = 0;
	alloc_highmem = 0;
}

/* Helper functions used for the shrinking of memory. */

#define GFP_IMAGE	(GFP_KERNEL | __GFP_NOWARN)

/**
 * preallocate_image_pages - Allocate a number of pages for hibernation image
 * @nr_pages: Number of page frames to allocate.
 * @mask: GFP flags to use for the allocation.
 *
 * Return value: Number of page frames actually allocated
 */
static unsigned long preallocate_image_pages(unsigned long nr_pages, gfp_t mask)
{
	unsigned long nr_alloc = 0;

	while (nr_pages > 0) {
		struct page *page;

		page = alloc_image_page(mask);
		if (!page)
			break;
		memory_bm_set_bit(&copy_bm, page_to_pfn(page));
		if (PageHighMem(page))
			alloc_highmem++;
		else
			alloc_normal++;
		nr_pages--;
		nr_alloc++;
	}

	return nr_alloc;
}

static unsigned long preallocate_image_memory(unsigned long nr_pages,
					      unsigned long avail_normal)
{
	unsigned long alloc;

	if (avail_normal <= alloc_normal)
		return 0;

	alloc = avail_normal - alloc_normal;
	if (nr_pages < alloc)
		alloc = nr_pages;

	return preallocate_image_pages(alloc, GFP_IMAGE);
}

#ifdef CONFIG_HIGHMEM
static unsigned long preallocate_image_highmem(unsigned long nr_pages)
{
	return preallocate_image_pages(nr_pages, GFP_IMAGE | __GFP_HIGHMEM);
}

/**
 *  __fraction - Compute (an approximation of) x * (multiplier / base)
 */
static unsigned long __fraction(u64 x, u64 multiplier, u64 base)
{
	x *= multiplier;
	do_div(x, base);
	return (unsigned long)x;
}

static unsigned long preallocate_highmem_fraction(unsigned long nr_pages,
						unsigned long highmem,
						unsigned long total)
{
	unsigned long alloc = __fraction(nr_pages, highmem, total);

	return preallocate_image_pages(alloc, GFP_IMAGE | __GFP_HIGHMEM);
}
#else /* CONFIG_HIGHMEM */
static inline unsigned long preallocate_image_highmem(unsigned long nr_pages)
{
	return 0;
}

static inline unsigned long preallocate_highmem_fraction(unsigned long nr_pages,
						unsigned long highmem,
						unsigned long total)
{
	return 0;
}
#endif /* CONFIG_HIGHMEM */

/**
 * free_unnecessary_pages - Release preallocated pages not needed for the image
 */
static void free_unnecessary_pages(void)
{
	unsigned long save, to_free_normal, to_free_highmem;

	save = count_data_pages();
	if (alloc_normal >= save) {
		to_free_normal = alloc_normal - save;
		save = 0;
	} else {
		to_free_normal = 0;
		save -= alloc_normal;
	}
	save += count_highmem_pages();
	if (alloc_highmem >= save) {
		to_free_highmem = alloc_highmem - save;
	} else {
		to_free_highmem = 0;
		save -= alloc_highmem;
		if (to_free_normal > save)
			to_free_normal -= save;
		else
			to_free_normal = 0;
	}

	memory_bm_position_reset(&copy_bm);

	while (to_free_normal > 0 || to_free_highmem > 0) {
		unsigned long pfn = memory_bm_next_pfn(&copy_bm);
		struct page *page = pfn_to_page(pfn);

		if (PageHighMem(page)) {
			if (!to_free_highmem)
				continue;
			to_free_highmem--;
			alloc_highmem--;
		} else {
			if (!to_free_normal)
				continue;
			to_free_normal--;
			alloc_normal--;
		}
		memory_bm_clear_bit(&copy_bm, pfn);
		swsusp_unset_page_forbidden(page);
		swsusp_unset_page_free(page);
		__free_page(page);
	}
}

/**
 * minimum_image_size - Estimate the minimum acceptable size of an image
 * @saveable: Number of saveable pages in the system.
 *
 * We want to avoid attempting to free too much memory too hard, so estimate the
 * minimum acceptable size of a hibernation image to use as the lower limit for
 * preallocating memory.
 *
 * We assume that the minimum image size should be proportional to
 *
 * [number of saveable pages] - [number of pages that can be freed in theory]
 *
 * where the second term is the sum of (1) reclaimable slab pages, (2) active
 * and (3) inactive anonymous pages, (4) active and (5) inactive file pages,
 * minus mapped file pages.
 */
static unsigned long minimum_image_size(unsigned long saveable)
{
	unsigned long size;

	size = global_page_state(NR_SLAB_RECLAIMABLE)
		+ global_page_state(NR_ACTIVE_ANON)
		+ global_page_state(NR_INACTIVE_ANON)
		+ global_page_state(NR_ACTIVE_FILE)
		+ global_page_state(NR_INACTIVE_FILE)
		- global_page_state(NR_FILE_MAPPED);

	return saveable <= size ? 0 : saveable - size;
}

/**
 * hibernate_preallocate_memory - Preallocate memory for hibernation image
 *
 * To create a hibernation image it is necessary to make a copy of every page
 * frame in use.  We also need a number of page frames to be free during
 * hibernation for allocations made while saving the image and for device
 * drivers, in case they need to allocate memory from their hibernation
 * callbacks (these two numbers are given by PAGES_FOR_IO (which is a rough
 * estimate) and reserverd_size divided by PAGE_SIZE (which is tunable through
 * /sys/power/reserved_size, respectively).  To make this happen, we compute the
 * total number of available page frames and allocate at least
 *
 * ([page frames total] + PAGES_FOR_IO + [metadata pages]) / 2
 *  + 2 * DIV_ROUND_UP(reserved_size, PAGE_SIZE)
 *
 * of them, which corresponds to the maximum size of a hibernation image.
 *
 * If image_size is set below the number following from the above formula,
 * the preallocation of memory is continued until the total number of saveable
 * pages in the system is below the requested image size or the minimum
 * acceptable image size returned by minimum_image_size(), whichever is greater.
 */
int hibernate_preallocate_memory(void)
{
	struct zone *zone;
	unsigned long saveable, size, max_size, count, highmem, pages = 0;
	unsigned long alloc, save_highmem, pages_highmem, avail_normal;
	ktime_t start, stop;
	int error;

	printk(KERN_INFO "PM: Preallocating image memory... ");
	start = ktime_get();

	error = memory_bm_create(&orig_bm, GFP_IMAGE, PG_ANY);
	if (error)
		goto err_out;

	error = memory_bm_create(&copy_bm, GFP_IMAGE, PG_ANY);
	if (error)
		goto err_out;

	alloc_normal = 0;
	alloc_highmem = 0;

	/* Count the number of saveable data pages. */
	save_highmem = count_highmem_pages();
	saveable = count_data_pages();

	/*
	 * Compute the total number of page frames we can use (count) and the
	 * number of pages needed for image metadata (size).
	 */
	count = saveable;
	saveable += save_highmem;
	highmem = save_highmem;
	size = 0;
	for_each_populated_zone(zone) {
		size += snapshot_additional_pages(zone);
		if (is_highmem(zone))
			highmem += zone_page_state(zone, NR_FREE_PAGES);
		else
			count += zone_page_state(zone, NR_FREE_PAGES);
	}
	avail_normal = count;
	count += highmem;
	count -= totalreserve_pages;

	/* Add number of pages required for page keys (s390 only). */
	size += page_key_additional_pages(saveable);

	/* Compute the maximum number of saveable pages to leave in memory. */
	max_size = (count - (size + PAGES_FOR_IO)) / 2
			- 2 * DIV_ROUND_UP(reserved_size, PAGE_SIZE);
	/* Compute the desired number of image pages specified by image_size. */
	size = DIV_ROUND_UP(image_size, PAGE_SIZE);
	if (size > max_size)
		size = max_size;
	/*
	 * If the desired number of image pages is at least as large as the
	 * current number of saveable pages in memory, allocate page frames for
	 * the image and we're done.
	 */
	if (size >= saveable) {
		pages = preallocate_image_highmem(save_highmem);
		pages += preallocate_image_memory(saveable - pages, avail_normal);
		goto out;
	}

	/* Estimate the minimum size of the image. */
	pages = minimum_image_size(saveable);
	/*
	 * To avoid excessive pressure on the normal zone, leave room in it to
	 * accommodate an image of the minimum size (unless it's already too
	 * small, in which case don't preallocate pages from it at all).
	 */
	if (avail_normal > pages)
		avail_normal -= pages;
	else
		avail_normal = 0;
	if (size < pages)
		size = min_t(unsigned long, pages, max_size);

	/*
	 * Let the memory management subsystem know that we're going to need a
	 * large number of page frames to allocate and make it free some memory.
	 * NOTE: If this is not done, performance will be hurt badly in some
	 * test cases.
	 */
	shrink_all_memory(saveable - size);

	/*
	 * The number of saveable pages in memory was too high, so apply some
	 * pressure to decrease it.  First, make room for the largest possible
	 * image and fail if that doesn't work.  Next, try to decrease the size
	 * of the image as much as indicated by 'size' using allocations from
	 * highmem and non-highmem zones separately.
	 */
	pages_highmem = preallocate_image_highmem(highmem / 2);
	alloc = count - max_size;
	if (alloc > pages_highmem)
		alloc -= pages_highmem;
	else
		alloc = 0;
	pages = preallocate_image_memory(alloc, avail_normal);
	if (pages < alloc) {
		/* We have exhausted non-highmem pages, try highmem. */
		alloc -= pages;
		pages += pages_highmem;
		pages_highmem = preallocate_image_highmem(alloc);
		if (pages_highmem < alloc)
			goto err_out;
		pages += pages_highmem;
		/*
		 * size is the desired number of saveable pages to leave in
		 * memory, so try to preallocate (all memory - size) pages.
		 */
		alloc = (count - pages) - size;
		pages += preallocate_image_highmem(alloc);
	} else {
		/*
		 * There are approximately max_size saveable pages at this point
		 * and we want to reduce this number down to size.
		 */
		alloc = max_size - size;
		size = preallocate_highmem_fraction(alloc, highmem, count);
		pages_highmem += size;
		alloc -= size;
		size = preallocate_image_memory(alloc, avail_normal);
		pages_highmem += preallocate_image_highmem(alloc - size);
		pages += pages_highmem + size;
	}

	/*
	 * We only need as many page frames for the image as there are saveable
	 * pages in memory, but we have allocated more.  Release the excessive
	 * ones now.
	 */
	free_unnecessary_pages();

 out:
	stop = ktime_get();
	printk(KERN_CONT "done (allocated %lu pages)\n", pages);
	swsusp_show_speed(start, stop, pages, "Allocated");

	return 0;

 err_out:
	printk(KERN_CONT "\n");
	swsusp_free();
	return -ENOMEM;
}

#ifdef CONFIG_HIGHMEM
/**
  *	count_pages_for_highmem - compute the number of non-highmem pages
  *	that will be necessary for creating copies of highmem pages.
  */

static unsigned int count_pages_for_highmem(unsigned int nr_highmem)
{
	unsigned int free_highmem = count_free_highmem_pages() + alloc_highmem;

	if (free_highmem >= nr_highmem)
		nr_highmem = 0;
	else
		nr_highmem -= free_highmem;

	return nr_highmem;
}
#else
static unsigned int
count_pages_for_highmem(unsigned int nr_highmem) { return 0; }
#endif /* CONFIG_HIGHMEM */

/**
 *	enough_free_mem - Make sure we have enough free memory for the
 *	snapshot image.
 */

static int enough_free_mem(unsigned int nr_pages, unsigned int nr_highmem)
{
	struct zone *zone;
	unsigned int free = alloc_normal;

	for_each_populated_zone(zone)
		if (!is_highmem(zone))
			free += zone_page_state(zone, NR_FREE_PAGES);

	nr_pages += count_pages_for_highmem(nr_highmem);
	pr_debug("PM: Normal pages needed: %u + %u, available pages: %u\n",
		nr_pages, PAGES_FOR_IO, free);

	return free > nr_pages + PAGES_FOR_IO;
}

#ifdef CONFIG_HIGHMEM
/**
 *	get_highmem_buffer - if there are some highmem pages in the suspend
 *	image, we may need the buffer to copy them and/or load their data.
 */

static inline int get_highmem_buffer(int safe_needed)
{
	buffer = get_image_page(GFP_ATOMIC | __GFP_COLD, safe_needed);
	return buffer ? 0 : -ENOMEM;
}

/**
 *	alloc_highmem_image_pages - allocate some highmem pages for the image.
 *	Try to allocate as many pages as needed, but if the number of free
 *	highmem pages is lesser than that, allocate them all.
 */

static inline unsigned int
alloc_highmem_pages(struct memory_bitmap *bm, unsigned int nr_highmem)
{
	unsigned int to_alloc = count_free_highmem_pages();

	if (to_alloc > nr_highmem)
		to_alloc = nr_highmem;

	nr_highmem -= to_alloc;
	while (to_alloc-- > 0) {
		struct page *page;

		page = alloc_image_page(__GFP_HIGHMEM);
		memory_bm_set_bit(bm, page_to_pfn(page));
	}
	return nr_highmem;
}
#else
static inline int get_highmem_buffer(int safe_needed) { return 0; }

static inline unsigned int
alloc_highmem_pages(struct memory_bitmap *bm, unsigned int n) { return 0; }
#endif /* CONFIG_HIGHMEM */

/**
 *	swsusp_alloc - allocate memory for the suspend image
 *
 *	We first try to allocate as many highmem pages as there are
 *	saveable highmem pages in the system.  If that fails, we allocate
 *	non-highmem pages for the copies of the remaining highmem ones.
 *
 *	In this approach it is likely that the copies of highmem pages will
 *	also be located in the high memory, because of the way in which
 *	copy_data_pages() works.
 */

static int
swsusp_alloc(struct memory_bitmap *orig_bm, struct memory_bitmap *copy_bm,
		unsigned int nr_pages, unsigned int nr_highmem)
{
	if (nr_highmem > 0) {
		if (get_highmem_buffer(PG_ANY))
			goto err_out;
		if (nr_highmem > alloc_highmem) {
			nr_highmem -= alloc_highmem;
			nr_pages += alloc_highmem_pages(copy_bm, nr_highmem);
		}
	}
	if (nr_pages > alloc_normal) {
		nr_pages -= alloc_normal;
		while (nr_pages-- > 0) {
			struct page *page;

			page = alloc_image_page(GFP_ATOMIC | __GFP_COLD);
			if (!page)
				goto err_out;
			memory_bm_set_bit(copy_bm, page_to_pfn(page));
		}
	}

	return 0;

 err_out:
	swsusp_free();
	return -ENOMEM;
}

asmlinkage __visible int swsusp_save(void)
{
	unsigned int nr_pages, nr_highmem;

	printk(KERN_INFO "PM: Creating hibernation image:\n");

	drain_local_pages(NULL);
	nr_pages = count_data_pages();
	nr_highmem = count_highmem_pages();
	printk(KERN_INFO "PM: Need to copy %u pages\n", nr_pages + nr_highmem);

	if (!enough_free_mem(nr_pages, nr_highmem)) {
		printk(KERN_ERR "PM: Not enough free memory\n");
		return -ENOMEM;
	}

	if (swsusp_alloc(&orig_bm, &copy_bm, nr_pages, nr_highmem)) {
		printk(KERN_ERR "PM: Memory allocation failed\n");
		return -ENOMEM;
	}

	/* During allocating of suspend pagedir, new cold pages may appear.
	 * Kill them.
	 */
	drain_local_pages(NULL);
	copy_data_pages(&copy_bm, &orig_bm);

	/*
	 * End of critical section. From now on, we can write to memory,
	 * but we should not touch disk. This specially means we must _not_
	 * touch swap space! Except we must write out our image of course.
	 */

	nr_pages += nr_highmem;
	nr_copy_pages = nr_pages;
	nr_meta_pages = DIV_ROUND_UP(nr_pages * sizeof(long), PAGE_SIZE);

	printk(KERN_INFO "PM: Hibernation image created (%d pages copied)\n",
		nr_pages);

	return 0;
}

#ifndef CONFIG_ARCH_HIBERNATION_HEADER
static int init_header_complete(struct swsusp_info *info)
{
	memcpy(&info->uts, init_utsname(), sizeof(struct new_utsname));
	info->version_code = LINUX_VERSION_CODE;
	return 0;
}

static char *check_image_kernel(struct swsusp_info *info)
{
	if (info->version_code != LINUX_VERSION_CODE)
		return "kernel version";
	if (strcmp(info->uts.sysname,init_utsname()->sysname))
		return "system type";
	if (strcmp(info->uts.release,init_utsname()->release))
		return "kernel release";
	if (strcmp(info->uts.version,init_utsname()->version))
		return "version";
	if (strcmp(info->uts.machine,init_utsname()->machine))
		return "machine";
	return NULL;
}
#endif /* CONFIG_ARCH_HIBERNATION_HEADER */

unsigned long snapshot_get_image_size(void)
{
	return nr_copy_pages + nr_meta_pages + 1;
}

static int init_header(struct swsusp_info *info)
{
	memset(info, 0, sizeof(struct swsusp_info));
	info->num_physpages = get_num_physpages();
	info->image_pages = nr_copy_pages;
	info->pages = snapshot_get_image_size();
	info->size = info->pages;
	info->size <<= PAGE_SHIFT;
	return init_header_complete(info);
}

/**
 *	pack_pfns - pfns corresponding to the set bits found in the bitmap @bm
 *	are stored in the array @buf[] (1 page at a time)
 */

static inline void
pack_pfns(unsigned long *buf, struct memory_bitmap *bm)
{
	int j;

	for (j = 0; j < PAGE_SIZE / sizeof(long); j++) {
		buf[j] = memory_bm_next_pfn(bm);
		if (unlikely(buf[j] == BM_END_OF_MAP))
			break;
		/* Save page key for data page (s390 only). */
		page_key_read(buf + j);
	}
}

/**
 *	snapshot_read_next - used for reading the system memory snapshot.
 *
 *	On the first call to it @handle should point to a zeroed
 *	snapshot_handle structure.  The structure gets updated and a pointer
 *	to it should be passed to this function every next time.
 *
 *	On success the function returns a positive number.  Then, the caller
 *	is allowed to read up to the returned number of bytes from the memory
 *	location computed by the data_of() macro.
 *
 *	The function returns 0 to indicate the end of data stream condition,
 *	and a negative number is returned on error.  In such cases the
 *	structure pointed to by @handle is not updated and should not be used
 *	any more.
 */

int snapshot_read_next(struct snapshot_handle *handle)
{
	if (handle->cur > nr_meta_pages + nr_copy_pages)
		return 0;

	if (!buffer) {
		/* This makes the buffer be freed by swsusp_free() */
		buffer = get_image_page(GFP_ATOMIC, PG_ANY);
		if (!buffer)
			return -ENOMEM;
	}
	if (!handle->cur) {
		int error;

		error = init_header((struct swsusp_info *)buffer);
		if (error)
			return error;
		handle->buffer = buffer;
		memory_bm_position_reset(&orig_bm);
		memory_bm_position_reset(&copy_bm);
	} else if (handle->cur <= nr_meta_pages) {
		clear_page(buffer);
		pack_pfns(buffer, &orig_bm);
	} else {
		struct page *page;

		page = pfn_to_page(memory_bm_next_pfn(&copy_bm));
		if (PageHighMem(page)) {
			/* Highmem pages are copied to the buffer,
			 * because we can't return with a kmapped
			 * highmem page (we may not be called again).
			 */
			void *kaddr;

			kaddr = kmap_atomic(page);
			copy_page(buffer, kaddr);
			kunmap_atomic(kaddr);
			handle->buffer = buffer;
		} else {
			handle->buffer = page_address(page);
		}
	}
	handle->cur++;
	return PAGE_SIZE;
}

/**
 *	mark_unsafe_pages - mark the pages that cannot be used for storing
 *	the image during resume, because they conflict with the pages that
 *	had been used before suspend
 */

static int mark_unsafe_pages(struct memory_bitmap *bm)
{
	struct zone *zone;
	unsigned long pfn, max_zone_pfn;

	/* Clear page flags */
	for_each_populated_zone(zone) {
		max_zone_pfn = zone_end_pfn(zone);
		for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
			if (pfn_valid(pfn))
				swsusp_unset_page_free(pfn_to_page(pfn));
	}

	/* Mark pages that correspond to the "original" pfns as "unsafe" */
	memory_bm_position_reset(bm);
	do {
		pfn = memory_bm_next_pfn(bm);
		if (likely(pfn != BM_END_OF_MAP)) {
			if (likely(pfn_valid(pfn)) && !is_nosave_page(pfn))
				swsusp_set_page_free(pfn_to_page(pfn));
			else
				return -EFAULT;
		}
	} while (pfn != BM_END_OF_MAP);

	allocated_unsafe_pages = 0;

	return 0;
}

static void
duplicate_memory_bitmap(struct memory_bitmap *dst, struct memory_bitmap *src)
{
	unsigned long pfn;

	memory_bm_position_reset(src);
	pfn = memory_bm_next_pfn(src);
	while (pfn != BM_END_OF_MAP) {
		memory_bm_set_bit(dst, pfn);
		pfn = memory_bm_next_pfn(src);
	}
}

static int check_header(struct swsusp_info *info)
{
	char *reason;

	reason = check_image_kernel(info);
	if (!reason && info->num_physpages != get_num_physpages())
		reason = "memory size";
	if (reason) {
		printk(KERN_ERR "PM: Image mismatch: %s\n", reason);
		return -EPERM;
	}
	return 0;
}

/**
 *	load header - check the image header and copy data from it
 */

static int
load_header(struct swsusp_info *info)
{
	int error;

	restore_pblist = NULL;
	error = check_header(info);
	if (!error) {
		nr_copy_pages = info->image_pages;
		nr_meta_pages = info->pages - info->image_pages - 1;
	}
	return error;
}

/**
 *	unpack_orig_pfns - for each element of @buf[] (1 page at a time) set
 *	the corresponding bit in the memory bitmap @bm
 */
static int unpack_orig_pfns(unsigned long *buf, struct memory_bitmap *bm)
{
	int j;

	for (j = 0; j < PAGE_SIZE / sizeof(long); j++) {
		if (unlikely(buf[j] == BM_END_OF_MAP))
			break;

		/* Extract and buffer page key for data page (s390 only). */
		page_key_memorize(buf + j);

		if (memory_bm_pfn_present(bm, buf[j]))
			memory_bm_set_bit(bm, buf[j]);
		else
			return -EFAULT;
	}

	return 0;
}

/* List of "safe" pages that may be used to store data loaded from the suspend
 * image
 */
static struct linked_page *safe_pages_list;

#ifdef CONFIG_HIGHMEM
/* struct highmem_pbe is used for creating the list of highmem pages that
 * should be restored atomically during the resume from disk, because the page
 * frames they have occupied before the suspend are in use.
 */
struct highmem_pbe {
	struct page *copy_page;	/* data is here now */
	struct page *orig_page;	/* data was here before the suspend */
	struct highmem_pbe *next;
};

/* List of highmem PBEs needed for restoring the highmem pages that were
 * allocated before the suspend and included in the suspend image, but have
 * also been allocated by the "resume" kernel, so their contents cannot be
 * written directly to their "original" page frames.
 */
static struct highmem_pbe *highmem_pblist;

/**
 *	count_highmem_image_pages - compute the number of highmem pages in the
 *	suspend image.  The bits in the memory bitmap @bm that correspond to the
 *	image pages are assumed to be set.
 */

static unsigned int count_highmem_image_pages(struct memory_bitmap *bm)
{
	unsigned long pfn;
	unsigned int cnt = 0;

	memory_bm_position_reset(bm);
	pfn = memory_bm_next_pfn(bm);
	while (pfn != BM_END_OF_MAP) {
		if (PageHighMem(pfn_to_page(pfn)))
			cnt++;

		pfn = memory_bm_next_pfn(bm);
	}
	return cnt;
}

/**
 *	prepare_highmem_image - try to allocate as many highmem pages as
 *	there are highmem image pages (@nr_highmem_p points to the variable
 *	containing the number of highmem image pages).  The pages that are
 *	"safe" (ie. will not be overwritten when the suspend image is
 *	restored) have the corresponding bits set in @bm (it must be
 *	unitialized).
 *
 *	NOTE: This function should not be called if there are no highmem
 *	image pages.
 */

static unsigned int safe_highmem_pages;

static struct memory_bitmap *safe_highmem_bm;

static int
prepare_highmem_image(struct memory_bitmap *bm, unsigned int *nr_highmem_p)
{
	unsigned int to_alloc;

	if (memory_bm_create(bm, GFP_ATOMIC, PG_SAFE))
		return -ENOMEM;

	if (get_highmem_buffer(PG_SAFE))
		return -ENOMEM;

	to_alloc = count_free_highmem_pages();
	if (to_alloc > *nr_highmem_p)
		to_alloc = *nr_highmem_p;
	else
		*nr_highmem_p = to_alloc;

	safe_highmem_pages = 0;
	while (to_alloc-- > 0) {
		struct page *page;

		page = alloc_page(__GFP_HIGHMEM);
		if (!swsusp_page_is_free(page)) {
			/* The page is "safe", set its bit the bitmap */
			memory_bm_set_bit(bm, page_to_pfn(page));
			safe_highmem_pages++;
		}
		/* Mark the page as allocated */
		swsusp_set_page_forbidden(page);
		swsusp_set_page_free(page);
	}
	memory_bm_position_reset(bm);
	safe_highmem_bm = bm;
	return 0;
}

/**
 *	get_highmem_page_buffer - for given highmem image page find the buffer
 *	that suspend_write_next() should set for its caller to write to.
 *
 *	If the page is to be saved to its "original" page frame or a copy of
 *	the page is to be made in the highmem, @buffer is returned.  Otherwise,
 *	the copy of the page is to be made in normal memory, so the address of
 *	the copy is returned.
 *
 *	If @buffer is returned, the caller of suspend_write_next() will write
 *	the page's contents to @buffer, so they will have to be copied to the
 *	right location on the next call to suspend_write_next() and it is done
 *	with the help of copy_last_highmem_page().  For this purpose, if
 *	@buffer is returned, @last_highmem page is set to the page to which
 *	the data will have to be copied from @buffer.
 */

static struct page *last_highmem_page;

static void *
get_highmem_page_buffer(struct page *page, struct chain_allocator *ca)
{
	struct highmem_pbe *pbe;
	void *kaddr;

	if (swsusp_page_is_forbidden(page) && swsusp_page_is_free(page)) {
		/* We have allocated the "original" page frame and we can
		 * use it directly to store the loaded page.
		 */
		last_highmem_page = page;
		return buffer;
	}
	/* The "original" page frame has not been allocated and we have to
	 * use a "safe" page frame to store the loaded page.
	 */
	pbe = chain_alloc(ca, sizeof(struct highmem_pbe));
	if (!pbe) {
		swsusp_free();
		return ERR_PTR(-ENOMEM);
	}
	pbe->orig_page = page;
	if (safe_highmem_pages > 0) {
		struct page *tmp;

		/* Copy of the page will be stored in high memory */
		kaddr = buffer;
		tmp = pfn_to_page(memory_bm_next_pfn(safe_highmem_bm));
		safe_highmem_pages--;
		last_highmem_page = tmp;
		pbe->copy_page = tmp;
	} else {
		/* Copy of the page will be stored in normal memory */
		kaddr = safe_pages_list;
		safe_pages_list = safe_pages_list->next;
		pbe->copy_page = virt_to_page(kaddr);
	}
	pbe->next = highmem_pblist;
	highmem_pblist = pbe;
	return kaddr;
}

/**
 *	copy_last_highmem_page - copy the contents of a highmem image from
 *	@buffer, where the caller of snapshot_write_next() has place them,
 *	to the right location represented by @last_highmem_page .
 */

static void copy_last_highmem_page(void)
{
	if (last_highmem_page) {
		void *dst;

		dst = kmap_atomic(last_highmem_page);
		copy_page(dst, buffer);
		kunmap_atomic(dst);
		last_highmem_page = NULL;
	}
}

static inline int last_highmem_page_copied(void)
{
	return !last_highmem_page;
}

static inline void free_highmem_data(void)
{
	if (safe_highmem_bm)
		memory_bm_free(safe_highmem_bm, PG_UNSAFE_CLEAR);

	if (buffer)
		free_image_page(buffer, PG_UNSAFE_CLEAR);
}
#else
static unsigned int
count_highmem_image_pages(struct memory_bitmap *bm) { return 0; }

static inline int
prepare_highmem_image(struct memory_bitmap *bm, unsigned int *nr_highmem_p)
{
	return 0;
}

static inline void *
get_highmem_page_buffer(struct page *page, struct chain_allocator *ca)
{
	return ERR_PTR(-EINVAL);
}

static inline void copy_last_highmem_page(void) {}
static inline int last_highmem_page_copied(void) { return 1; }
static inline void free_highmem_data(void) {}
#endif /* CONFIG_HIGHMEM */

/**
 *	prepare_image - use the memory bitmap @bm to mark the pages that will
 *	be overwritten in the process of restoring the system memory state
 *	from the suspend image ("unsafe" pages) and allocate memory for the
 *	image.
 *
 *	The idea is to allocate a new memory bitmap first and then allocate
 *	as many pages as needed for the image data, but not to assign these
 *	pages to specific tasks initially.  Instead, we just mark them as
 *	allocated and create a lists of "safe" pages that will be used
 *	later.  On systems with high memory a list of "safe" highmem pages is
 *	also created.
 */

#define PBES_PER_LINKED_PAGE	(LINKED_PAGE_DATA_SIZE / sizeof(struct pbe))

static int
prepare_image(struct memory_bitmap *new_bm, struct memory_bitmap *bm)
{
	unsigned int nr_pages, nr_highmem;
	struct linked_page *sp_list, *lp;
	int error;

	/* If there is no highmem, the buffer will not be necessary */
	free_image_page(buffer, PG_UNSAFE_CLEAR);
	buffer = NULL;

	nr_highmem = count_highmem_image_pages(bm);
	error = mark_unsafe_pages(bm);
	if (error)
		goto Free;

	error = memory_bm_create(new_bm, GFP_ATOMIC, PG_SAFE);
	if (error)
		goto Free;

	duplicate_memory_bitmap(new_bm, bm);
	memory_bm_free(bm, PG_UNSAFE_KEEP);
	if (nr_highmem > 0) {
		error = prepare_highmem_image(bm, &nr_highmem);
		if (error)
			goto Free;
	}
	/* Reserve some safe pages for potential later use.
	 *
	 * NOTE: This way we make sure there will be enough safe pages for the
	 * chain_alloc() in get_buffer().  It is a bit wasteful, but
	 * nr_copy_pages cannot be greater than 50% of the memory anyway.
	 */
	sp_list = NULL;
	/* nr_copy_pages cannot be lesser than allocated_unsafe_pages */
	nr_pages = nr_copy_pages - nr_highmem - allocated_unsafe_pages;
	nr_pages = DIV_ROUND_UP(nr_pages, PBES_PER_LINKED_PAGE);
	while (nr_pages > 0) {
		lp = get_image_page(GFP_ATOMIC, PG_SAFE);
		if (!lp) {
			error = -ENOMEM;
			goto Free;
		}
		lp->next = sp_list;
		sp_list = lp;
		nr_pages--;
	}
	/* Preallocate memory for the image */
	safe_pages_list = NULL;
	nr_pages = nr_copy_pages - nr_highmem - allocated_unsafe_pages;
	while (nr_pages > 0) {
		lp = (struct linked_page *)get_zeroed_page(GFP_ATOMIC);
		if (!lp) {
			error = -ENOMEM;
			goto Free;
		}
		if (!swsusp_page_is_free(virt_to_page(lp))) {
			/* The page is "safe", add it to the list */
			lp->next = safe_pages_list;
			safe_pages_list = lp;
		}
		/* Mark the page as allocated */
		swsusp_set_page_forbidden(virt_to_page(lp));
		swsusp_set_page_free(virt_to_page(lp));
		nr_pages--;
	}
	/* Free the reserved safe pages so that chain_alloc() can use them */
	while (sp_list) {
		lp = sp_list->next;
		free_image_page(sp_list, PG_UNSAFE_CLEAR);
		sp_list = lp;
	}
	return 0;

 Free:
	swsusp_free();
	return error;
}

/**
 *	get_buffer - compute the address that snapshot_write_next() should
 *	set for its caller to write to.
 */

static void *get_buffer(struct memory_bitmap *bm, struct chain_allocator *ca)
{
	struct pbe *pbe;
	struct page *page;
	unsigned long pfn = memory_bm_next_pfn(bm);

	if (pfn == BM_END_OF_MAP)
		return ERR_PTR(-EFAULT);

	page = pfn_to_page(pfn);
	if (PageHighMem(page))
		return get_highmem_page_buffer(page, ca);

	if (swsusp_page_is_forbidden(page) && swsusp_page_is_free(page))
		/* We have allocated the "original" page frame and we can
		 * use it directly to store the loaded page.
		 */
		return page_address(page);

	/* The "original" page frame has not been allocated and we have to
	 * use a "safe" page frame to store the loaded page.
	 */
	pbe = chain_alloc(ca, sizeof(struct pbe));
	if (!pbe) {
		swsusp_free();
		return ERR_PTR(-ENOMEM);
	}
	pbe->orig_address = page_address(page);
	pbe->address = safe_pages_list;
	safe_pages_list = safe_pages_list->next;
	pbe->next = restore_pblist;
	restore_pblist = pbe;
	return pbe->address;
}

/**
 *	snapshot_write_next - used for writing the system memory snapshot.
 *
 *	On the first call to it @handle should point to a zeroed
 *	snapshot_handle structure.  The structure gets updated and a pointer
 *	to it should be passed to this function every next time.
 *
 *	On success the function returns a positive number.  Then, the caller
 *	is allowed to write up to the returned number of bytes to the memory
 *	location computed by the data_of() macro.
 *
 *	The function returns 0 to indicate the "end of file" condition,
 *	and a negative number is returned on error.  In such cases the
 *	structure pointed to by @handle is not updated and should not be used
 *	any more.
 */

int snapshot_write_next(struct snapshot_handle *handle)
{
	static struct chain_allocator ca;
	int error = 0;

	/* Check if we have already loaded the entire image */
	if (handle->cur > 1 && handle->cur > nr_meta_pages + nr_copy_pages)
		return 0;

	handle->sync_read = 1;

	if (!handle->cur) {
		if (!buffer)
			/* This makes the buffer be freed by swsusp_free() */
			buffer = get_image_page(GFP_ATOMIC, PG_ANY);

		if (!buffer)
			return -ENOMEM;

		handle->buffer = buffer;
	} else if (handle->cur == 1) {
		error = load_header(buffer);
		if (error)
			return error;

		error = memory_bm_create(&copy_bm, GFP_ATOMIC, PG_ANY);
		if (error)
			return error;

		/* Allocate buffer for page keys. */
		error = page_key_alloc(nr_copy_pages);
		if (error)
			return error;

	} else if (handle->cur <= nr_meta_pages + 1) {
		error = unpack_orig_pfns(buffer, &copy_bm);
		if (error)
			return error;

		if (handle->cur == nr_meta_pages + 1) {
			error = prepare_image(&orig_bm, &copy_bm);
			if (error)
				return error;

			chain_init(&ca, GFP_ATOMIC, PG_SAFE);
			memory_bm_position_reset(&orig_bm);
			restore_pblist = NULL;
			handle->buffer = get_buffer(&orig_bm, &ca);
			handle->sync_read = 0;
			if (IS_ERR(handle->buffer))
				return PTR_ERR(handle->buffer);
		}
	} else {
		copy_last_highmem_page();
		/* Restore page key for data page (s390 only). */
		page_key_write(handle->buffer);
		handle->buffer = get_buffer(&orig_bm, &ca);
		if (IS_ERR(handle->buffer))
			return PTR_ERR(handle->buffer);
		if (handle->buffer != buffer)
			handle->sync_read = 0;
	}
	handle->cur++;
	return PAGE_SIZE;
}

/**
 *	snapshot_write_finalize - must be called after the last call to
 *	snapshot_write_next() in case the last page in the image happens
 *	to be a highmem page and its contents should be stored in the
 *	highmem.  Additionally, it releases the memory that will not be
 *	used any more.
 */

void snapshot_write_finalize(struct snapshot_handle *handle)
{
	copy_last_highmem_page();
	/* Restore page key for data page (s390 only). */
	page_key_write(handle->buffer);
	page_key_free();
	/* Free only if we have loaded the image entirely */
	if (handle->cur > 1 && handle->cur > nr_meta_pages + nr_copy_pages) {
		memory_bm_free(&orig_bm, PG_UNSAFE_CLEAR);
		free_highmem_data();
	}
}

int snapshot_image_loaded(struct snapshot_handle *handle)
{
	return !(!nr_copy_pages || !last_highmem_page_copied() ||
			handle->cur <= nr_meta_pages + nr_copy_pages);
}

#ifdef CONFIG_HIGHMEM
/* Assumes that @buf is ready and points to a "safe" page */
static inline void
swap_two_pages_data(struct page *p1, struct page *p2, void *buf)
{
	void *kaddr1, *kaddr2;

	kaddr1 = kmap_atomic(p1);
	kaddr2 = kmap_atomic(p2);
	copy_page(buf, kaddr1);
	copy_page(kaddr1, kaddr2);
	copy_page(kaddr2, buf);
	kunmap_atomic(kaddr2);
	kunmap_atomic(kaddr1);
}

/**
 *	restore_highmem - for each highmem page that was allocated before
 *	the suspend and included in the suspend image, and also has been
 *	allocated by the "resume" kernel swap its current (ie. "before
 *	resume") contents with the previous (ie. "before suspend") one.
 *
 *	If the resume eventually fails, we can call this function once
 *	again and restore the "before resume" highmem state.
 */

int restore_highmem(void)
{
	struct highmem_pbe *pbe = highmem_pblist;
	void *buf;

	if (!pbe)
		return 0;

	buf = get_image_page(GFP_ATOMIC, PG_SAFE);
	if (!buf)
		return -ENOMEM;

	while (pbe) {
		swap_two_pages_data(pbe->copy_page, pbe->orig_page, buf);
		pbe = pbe->next;
	}
	free_image_page(buf, PG_UNSAFE_CLEAR);
	return 0;
}
#endif /* CONFIG_HIGHMEM */