summaryrefslogtreecommitdiff
path: root/arch/x86/kernel/e820.c
blob: ed858e9e9a7461aa9b4f8aa42a52c79d57d84507 (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
/*
 * Handle the memory map.
 * The functions here do the job until bootmem takes over.
 *
 *  Getting sanitize_e820_map() in sync with i386 version by applying change:
 *  -  Provisions for empty E820 memory regions (reported by certain BIOSes).
 *     Alex Achenbach <xela@slit.de>, December 2002.
 *  Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
 *
 */
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/crash_dump.h>
#include <linux/export.h>
#include <linux/bootmem.h>
#include <linux/pfn.h>
#include <linux/suspend.h>
#include <linux/acpi.h>
#include <linux/firmware-map.h>
#include <linux/memblock.h>
#include <linux/sort.h>

#include <asm/e820.h>
#include <asm/proto.h>
#include <asm/setup.h>

/*
 * The e820 map is the map that gets modified e.g. with command line parameters
 * and that is also registered with modifications in the kernel resource tree
 * with the iomem_resource as parent.
 *
 * The e820_saved is directly saved after the BIOS-provided memory map is
 * copied. It doesn't get modified afterwards. It's registered for the
 * /sys/firmware/memmap interface.
 *
 * That memory map is not modified and is used as base for kexec. The kexec'd
 * kernel should get the same memory map as the firmware provides. Then the
 * user can e.g. boot the original kernel with mem=1G while still booting the
 * next kernel with full memory.
 */
struct e820map e820;
struct e820map e820_saved;

/* For PCI or other memory-mapped resources */
unsigned long pci_mem_start = 0xaeedbabe;
#ifdef CONFIG_PCI
EXPORT_SYMBOL(pci_mem_start);
#endif

/*
 * This function checks if any part of the range <start,end> is mapped
 * with type.
 */
int
e820_any_mapped(u64 start, u64 end, unsigned type)
{
	int i;

	for (i = 0; i < e820.nr_map; i++) {
		struct e820entry *ei = &e820.map[i];

		if (type && ei->type != type)
			continue;
		if (ei->addr >= end || ei->addr + ei->size <= start)
			continue;
		return 1;
	}
	return 0;
}
EXPORT_SYMBOL_GPL(e820_any_mapped);

/*
 * This function checks if the entire range <start,end> is mapped with type.
 *
 * Note: this function only works correct if the e820 table is sorted and
 * not-overlapping, which is the case
 */
int __init e820_all_mapped(u64 start, u64 end, unsigned type)
{
	int i;

	for (i = 0; i < e820.nr_map; i++) {
		struct e820entry *ei = &e820.map[i];

		if (type && ei->type != type)
			continue;
		/* is the region (part) in overlap with the current region ?*/
		if (ei->addr >= end || ei->addr + ei->size <= start)
			continue;

		/* if the region is at the beginning of <start,end> we move
		 * start to the end of the region since it's ok until there
		 */
		if (ei->addr <= start)
			start = ei->addr + ei->size;
		/*
		 * if start is now at or beyond end, we're done, full
		 * coverage
		 */
		if (start >= end)
			return 1;
	}
	return 0;
}

/*
 * Add a memory region to the kernel e820 map.
 */
static void __init __e820_add_region(struct e820map *e820x, u64 start, u64 size,
					 int type)
{
	int x = e820x->nr_map;

	if (x >= ARRAY_SIZE(e820x->map)) {
		printk(KERN_ERR "e820: too many entries; ignoring [mem %#010llx-%#010llx]\n",
		       (unsigned long long) start,
		       (unsigned long long) (start + size - 1));
		return;
	}

	e820x->map[x].addr = start;
	e820x->map[x].size = size;
	e820x->map[x].type = type;
	e820x->nr_map++;
}

void __init e820_add_region(u64 start, u64 size, int type)
{
	__e820_add_region(&e820, start, size, type);
}

static void __init e820_print_type(u32 type)
{
	switch (type) {
	case E820_RAM:
	case E820_RESERVED_KERN:
		printk(KERN_CONT "usable");
		break;
	case E820_RESERVED:
		printk(KERN_CONT "reserved");
		break;
	case E820_ACPI:
		printk(KERN_CONT "ACPI data");
		break;
	case E820_NVS:
		printk(KERN_CONT "ACPI NVS");
		break;
	case E820_UNUSABLE:
		printk(KERN_CONT "unusable");
		break;
	default:
		printk(KERN_CONT "type %u", type);
		break;
	}
}

void __init e820_print_map(char *who)
{
	int i;

	for (i = 0; i < e820.nr_map; i++) {
		printk(KERN_INFO "%s: [mem %#018Lx-%#018Lx] ", who,
		       (unsigned long long) e820.map[i].addr,
		       (unsigned long long)
		       (e820.map[i].addr + e820.map[i].size - 1));
		e820_print_type(e820.map[i].type);
		printk(KERN_CONT "\n");
	}
}

/*
 * Sanitize the BIOS e820 map.
 *
 * Some e820 responses include overlapping entries. The following
 * replaces the original e820 map with a new one, removing overlaps,
 * and resolving conflicting memory types in favor of highest
 * numbered type.
 *
 * The input parameter biosmap points to an array of 'struct
 * e820entry' which on entry has elements in the range [0, *pnr_map)
 * valid, and which has space for up to max_nr_map entries.
 * On return, the resulting sanitized e820 map entries will be in
 * overwritten in the same location, starting at biosmap.
 *
 * The integer pointed to by pnr_map must be valid on entry (the
 * current number of valid entries located at biosmap) and will
 * be updated on return, with the new number of valid entries
 * (something no more than max_nr_map.)
 *
 * The return value from sanitize_e820_map() is zero if it
 * successfully 'sanitized' the map entries passed in, and is -1
 * if it did nothing, which can happen if either of (1) it was
 * only passed one map entry, or (2) any of the input map entries
 * were invalid (start + size < start, meaning that the size was
 * so big the described memory range wrapped around through zero.)
 *
 *	Visually we're performing the following
 *	(1,2,3,4 = memory types)...
 *
 *	Sample memory map (w/overlaps):
 *	   ____22__________________
 *	   ______________________4_
 *	   ____1111________________
 *	   _44_____________________
 *	   11111111________________
 *	   ____________________33__
 *	   ___________44___________
 *	   __________33333_________
 *	   ______________22________
 *	   ___________________2222_
 *	   _________111111111______
 *	   _____________________11_
 *	   _________________4______
 *
 *	Sanitized equivalent (no overlap):
 *	   1_______________________
 *	   _44_____________________
 *	   ___1____________________
 *	   ____22__________________
 *	   ______11________________
 *	   _________1______________
 *	   __________3_____________
 *	   ___________44___________
 *	   _____________33_________
 *	   _______________2________
 *	   ________________1_______
 *	   _________________4______
 *	   ___________________2____
 *	   ____________________33__
 *	   ______________________4_
 */
struct change_member {
	struct e820entry *pbios; /* pointer to original bios entry */
	unsigned long long addr; /* address for this change point */
};

static int __init cpcompare(const void *a, const void *b)
{
	struct change_member * const *app = a, * const *bpp = b;
	const struct change_member *ap = *app, *bp = *bpp;

	/*
	 * Inputs are pointers to two elements of change_point[].  If their
	 * addresses are unequal, their difference dominates.  If the addresses
	 * are equal, then consider one that represents the end of its region
	 * to be greater than one that does not.
	 */
	if (ap->addr != bp->addr)
		return ap->addr > bp->addr ? 1 : -1;

	return (ap->addr != ap->pbios->addr) - (bp->addr != bp->pbios->addr);
}

int __init sanitize_e820_map(struct e820entry *biosmap, int max_nr_map,
			     u32 *pnr_map)
{
	static struct change_member change_point_list[2*E820_X_MAX] __initdata;
	static struct change_member *change_point[2*E820_X_MAX] __initdata;
	static struct e820entry *overlap_list[E820_X_MAX] __initdata;
	static struct e820entry new_bios[E820_X_MAX] __initdata;
	unsigned long current_type, last_type;
	unsigned long long last_addr;
	int chgidx;
	int overlap_entries;
	int new_bios_entry;
	int old_nr, new_nr, chg_nr;
	int i;

	/* if there's only one memory region, don't bother */
	if (*pnr_map < 2)
		return -1;

	old_nr = *pnr_map;
	BUG_ON(old_nr > max_nr_map);

	/* bail out if we find any unreasonable addresses in bios map */
	for (i = 0; i < old_nr; i++)
		if (biosmap[i].addr + biosmap[i].size < biosmap[i].addr)
			return -1;

	/* create pointers for initial change-point information (for sorting) */
	for (i = 0; i < 2 * old_nr; i++)
		change_point[i] = &change_point_list[i];

	/* record all known change-points (starting and ending addresses),
	   omitting those that are for empty memory regions */
	chgidx = 0;
	for (i = 0; i < old_nr; i++)	{
		if (biosmap[i].size != 0) {
			change_point[chgidx]->addr = biosmap[i].addr;
			change_point[chgidx++]->pbios = &biosmap[i];
			change_point[chgidx]->addr = biosmap[i].addr +
				biosmap[i].size;
			change_point[chgidx++]->pbios = &biosmap[i];
		}
	}
	chg_nr = chgidx;

	/* sort change-point list by memory addresses (low -> high) */
	sort(change_point, chg_nr, sizeof *change_point, cpcompare, NULL);

	/* create a new bios memory map, removing overlaps */
	overlap_entries = 0;	 /* number of entries in the overlap table */
	new_bios_entry = 0;	 /* index for creating new bios map entries */
	last_type = 0;		 /* start with undefined memory type */
	last_addr = 0;		 /* start with 0 as last starting address */

	/* loop through change-points, determining affect on the new bios map */
	for (chgidx = 0; chgidx < chg_nr; chgidx++) {
		/* keep track of all overlapping bios entries */
		if (change_point[chgidx]->addr ==
		    change_point[chgidx]->pbios->addr) {
			/*
			 * add map entry to overlap list (> 1 entry
			 * implies an overlap)
			 */
			overlap_list[overlap_entries++] =
				change_point[chgidx]->pbios;
		} else {
			/*
			 * remove entry from list (order independent,
			 * so swap with last)
			 */
			for (i = 0; i < overlap_entries; i++) {
				if (overlap_list[i] ==
				    change_point[chgidx]->pbios)
					overlap_list[i] =
						overlap_list[overlap_entries-1];
			}
			overlap_entries--;
		}
		/*
		 * if there are overlapping entries, decide which
		 * "type" to use (larger value takes precedence --
		 * 1=usable, 2,3,4,4+=unusable)
		 */
		current_type = 0;
		for (i = 0; i < overlap_entries; i++)
			if (overlap_list[i]->type > current_type)
				current_type = overlap_list[i]->type;
		/*
		 * continue building up new bios map based on this
		 * information
		 */
		if (current_type != last_type)	{
			if (last_type != 0)	 {
				new_bios[new_bios_entry].size =
					change_point[chgidx]->addr - last_addr;
				/*
				 * move forward only if the new size
				 * was non-zero
				 */
				if (new_bios[new_bios_entry].size != 0)
					/*
					 * no more space left for new
					 * bios entries ?
					 */
					if (++new_bios_entry >= max_nr_map)
						break;
			}
			if (current_type != 0)	{
				new_bios[new_bios_entry].addr =
					change_point[chgidx]->addr;
				new_bios[new_bios_entry].type = current_type;
				last_addr = change_point[chgidx]->addr;
			}
			last_type = current_type;
		}
	}
	/* retain count for new bios entries */
	new_nr = new_bios_entry;

	/* copy new bios mapping into original location */
	memcpy(biosmap, new_bios, new_nr * sizeof(struct e820entry));
	*pnr_map = new_nr;

	return 0;
}

static int __init __append_e820_map(struct e820entry *biosmap, int nr_map)
{
	while (nr_map) {
		u64 start = biosmap->addr;
		u64 size = biosmap->size;
		u64 end = start + size;
		u32 type = biosmap->type;

		/* Overflow in 64 bits? Ignore the memory map. */
		if (start > end)
			return -1;

		e820_add_region(start, size, type);

		biosmap++;
		nr_map--;
	}
	return 0;
}

/*
 * Copy the BIOS e820 map into a safe place.
 *
 * Sanity-check it while we're at it..
 *
 * If we're lucky and live on a modern system, the setup code
 * will have given us a memory map that we can use to properly
 * set up memory.  If we aren't, we'll fake a memory map.
 */
static int __init append_e820_map(struct e820entry *biosmap, int nr_map)
{
	/* Only one memory region (or negative)? Ignore it */
	if (nr_map < 2)
		return -1;

	return __append_e820_map(biosmap, nr_map);
}

static u64 __init __e820_update_range(struct e820map *e820x, u64 start,
					u64 size, unsigned old_type,
					unsigned new_type)
{
	u64 end;
	unsigned int i;
	u64 real_updated_size = 0;

	BUG_ON(old_type == new_type);

	if (size > (ULLONG_MAX - start))
		size = ULLONG_MAX - start;

	end = start + size;
	printk(KERN_DEBUG "e820: update [mem %#010Lx-%#010Lx] ",
	       (unsigned long long) start, (unsigned long long) (end - 1));
	e820_print_type(old_type);
	printk(KERN_CONT " ==> ");
	e820_print_type(new_type);
	printk(KERN_CONT "\n");

	for (i = 0; i < e820x->nr_map; i++) {
		struct e820entry *ei = &e820x->map[i];
		u64 final_start, final_end;
		u64 ei_end;

		if (ei->type != old_type)
			continue;

		ei_end = ei->addr + ei->size;
		/* totally covered by new range? */
		if (ei->addr >= start && ei_end <= end) {
			ei->type = new_type;
			real_updated_size += ei->size;
			continue;
		}

		/* new range is totally covered? */
		if (ei->addr < start && ei_end > end) {
			__e820_add_region(e820x, start, size, new_type);
			__e820_add_region(e820x, end, ei_end - end, ei->type);
			ei->size = start - ei->addr;
			real_updated_size += size;
			continue;
		}

		/* partially covered */
		final_start = max(start, ei->addr);
		final_end = min(end, ei_end);
		if (final_start >= final_end)
			continue;

		__e820_add_region(e820x, final_start, final_end - final_start,
				  new_type);

		real_updated_size += final_end - final_start;

		/*
		 * left range could be head or tail, so need to update
		 * size at first.
		 */
		ei->size -= final_end - final_start;
		if (ei->addr < final_start)
			continue;
		ei->addr = final_end;
	}
	return real_updated_size;
}

u64 __init e820_update_range(u64 start, u64 size, unsigned old_type,
			     unsigned new_type)
{
	return __e820_update_range(&e820, start, size, old_type, new_type);
}

static u64 __init e820_update_range_saved(u64 start, u64 size,
					  unsigned old_type, unsigned new_type)
{
	return __e820_update_range(&e820_saved, start, size, old_type,
				     new_type);
}

/* make e820 not cover the range */
u64 __init e820_remove_range(u64 start, u64 size, unsigned old_type,
			     int checktype)
{
	int i;
	u64 end;
	u64 real_removed_size = 0;

	if (size > (ULLONG_MAX - start))
		size = ULLONG_MAX - start;

	end = start + size;
	printk(KERN_DEBUG "e820: remove [mem %#010Lx-%#010Lx] ",
	       (unsigned long long) start, (unsigned long long) (end - 1));
	if (checktype)
		e820_print_type(old_type);
	printk(KERN_CONT "\n");

	for (i = 0; i < e820.nr_map; i++) {
		struct e820entry *ei = &e820.map[i];
		u64 final_start, final_end;
		u64 ei_end;

		if (checktype && ei->type != old_type)
			continue;

		ei_end = ei->addr + ei->size;
		/* totally covered? */
		if (ei->addr >= start && ei_end <= end) {
			real_removed_size += ei->size;
			memset(ei, 0, sizeof(struct e820entry));
			continue;
		}

		/* new range is totally covered? */
		if (ei->addr < start && ei_end > end) {
			e820_add_region(end, ei_end - end, ei->type);
			ei->size = start - ei->addr;
			real_removed_size += size;
			continue;
		}

		/* partially covered */
		final_start = max(start, ei->addr);
		final_end = min(end, ei_end);
		if (final_start >= final_end)
			continue;
		real_removed_size += final_end - final_start;

		/*
		 * left range could be head or tail, so need to update
		 * size at first.
		 */
		ei->size -= final_end - final_start;
		if (ei->addr < final_start)
			continue;
		ei->addr = final_end;
	}
	return real_removed_size;
}

void __init update_e820(void)
{
	u32 nr_map;

	nr_map = e820.nr_map;
	if (sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &nr_map))
		return;
	e820.nr_map = nr_map;
	printk(KERN_INFO "e820: modified physical RAM map:\n");
	e820_print_map("modified");
}
static void __init update_e820_saved(void)
{
	u32 nr_map;

	nr_map = e820_saved.nr_map;
	if (sanitize_e820_map(e820_saved.map, ARRAY_SIZE(e820_saved.map), &nr_map))
		return;
	e820_saved.nr_map = nr_map;
}
#define MAX_GAP_END 0x100000000ull
/*
 * Search for a gap in the e820 memory space from start_addr to end_addr.
 */
__init int e820_search_gap(unsigned long *gapstart, unsigned long *gapsize,
		unsigned long start_addr, unsigned long long end_addr)
{
	unsigned long long last;
	int i = e820.nr_map;
	int found = 0;

	last = (end_addr && end_addr < MAX_GAP_END) ? end_addr : MAX_GAP_END;

	while (--i >= 0) {
		unsigned long long start = e820.map[i].addr;
		unsigned long long end = start + e820.map[i].size;

		if (end < start_addr)
			continue;

		/*
		 * Since "last" is at most 4GB, we know we'll
		 * fit in 32 bits if this condition is true
		 */
		if (last > end) {
			unsigned long gap = last - end;

			if (gap >= *gapsize) {
				*gapsize = gap;
				*gapstart = end;
				found = 1;
			}
		}
		if (start < last)
			last = start;
	}
	return found;
}

/*
 * Search for the biggest gap in the low 32 bits of the e820
 * memory space.  We pass this space to PCI to assign MMIO resources
 * for hotplug or unconfigured devices in.
 * Hopefully the BIOS let enough space left.
 */
__init void e820_setup_gap(void)
{
	unsigned long gapstart, gapsize;
	int found;

	gapstart = 0x10000000;
	gapsize = 0x400000;
	found  = e820_search_gap(&gapstart, &gapsize, 0, MAX_GAP_END);

#ifdef CONFIG_X86_64
	if (!found) {
		gapstart = (max_pfn << PAGE_SHIFT) + 1024*1024;
		printk(KERN_ERR
	"e820: cannot find a gap in the 32bit address range\n"
	"e820: PCI devices with unassigned 32bit BARs may break!\n");
	}
#endif

	/*
	 * e820_reserve_resources_late protect stolen RAM already
	 */
	pci_mem_start = gapstart;

	printk(KERN_INFO
	       "e820: [mem %#010lx-%#010lx] available for PCI devices\n",
	       gapstart, gapstart + gapsize - 1);
}

/**
 * Because of the size limitation of struct boot_params, only first
 * 128 E820 memory entries are passed to kernel via
 * boot_params.e820_map, others are passed via SETUP_E820_EXT node of
 * linked list of struct setup_data, which is parsed here.
 */
void __init parse_e820_ext(struct setup_data *sdata)
{
	int entries;
	struct e820entry *extmap;

	entries = sdata->len / sizeof(struct e820entry);
	extmap = (struct e820entry *)(sdata->data);
	__append_e820_map(extmap, entries);
	sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
	printk(KERN_INFO "e820: extended physical RAM map:\n");
	e820_print_map("extended");
}

#if defined(CONFIG_X86_64) || \
	(defined(CONFIG_X86_32) && defined(CONFIG_HIBERNATION))
/**
 * Find the ranges of physical addresses that do not correspond to
 * e820 RAM areas and mark the corresponding pages as nosave for
 * hibernation (32 bit) or software suspend and suspend to RAM (64 bit).
 *
 * This function requires the e820 map to be sorted and without any
 * overlapping entries and assumes the first e820 area to be RAM.
 */
void __init e820_mark_nosave_regions(unsigned long limit_pfn)
{
	int i;
	unsigned long pfn;

	pfn = PFN_DOWN(e820.map[0].addr + e820.map[0].size);
	for (i = 1; i < e820.nr_map; i++) {
		struct e820entry *ei = &e820.map[i];

		if (pfn < PFN_UP(ei->addr))
			register_nosave_region(pfn, PFN_UP(ei->addr));

		pfn = PFN_DOWN(ei->addr + ei->size);
		if (ei->type != E820_RAM && ei->type != E820_RESERVED_KERN)
			register_nosave_region(PFN_UP(ei->addr), pfn);

		if (pfn >= limit_pfn)
			break;
	}
}
#endif

#ifdef CONFIG_ACPI
/**
 * Mark ACPI NVS memory region, so that we can save/restore it during
 * hibernation and the subsequent resume.
 */
static int __init e820_mark_nvs_memory(void)
{
	int i;

	for (i = 0; i < e820.nr_map; i++) {
		struct e820entry *ei = &e820.map[i];

		if (ei->type == E820_NVS)
			acpi_nvs_register(ei->addr, ei->size);
	}

	return 0;
}
core_initcall(e820_mark_nvs_memory);
#endif

/*
 * pre allocated 4k and reserved it in memblock and e820_saved
 */
u64 __init early_reserve_e820(u64 size, u64 align)
{
	u64 addr;

	addr = __memblock_alloc_base(size, align, MEMBLOCK_ALLOC_ACCESSIBLE);
	if (addr) {
		e820_update_range_saved(addr, size, E820_RAM, E820_RESERVED);
		printk(KERN_INFO "e820: update e820_saved for early_reserve_e820\n");
		update_e820_saved();
	}

	return addr;
}

#ifdef CONFIG_X86_32
# ifdef CONFIG_X86_PAE
#  define MAX_ARCH_PFN		(1ULL<<(36-PAGE_SHIFT))
# else
#  define MAX_ARCH_PFN		(1ULL<<(32-PAGE_SHIFT))
# endif
#else /* CONFIG_X86_32 */
# define MAX_ARCH_PFN MAXMEM>>PAGE_SHIFT
#endif

/*
 * Find the highest page frame number we have available
 */
static unsigned long __init e820_end_pfn(unsigned long limit_pfn, unsigned type)
{
	int i;
	unsigned long last_pfn = 0;
	unsigned long max_arch_pfn = MAX_ARCH_PFN;

	for (i = 0; i < e820.nr_map; i++) {
		struct e820entry *ei = &e820.map[i];
		unsigned long start_pfn;
		unsigned long end_pfn;

		if (ei->type != type)
			continue;

		start_pfn = ei->addr >> PAGE_SHIFT;
		end_pfn = (ei->addr + ei->size) >> PAGE_SHIFT;

		if (start_pfn >= limit_pfn)
			continue;
		if (end_pfn > limit_pfn) {
			last_pfn = limit_pfn;
			break;
		}
		if (end_pfn > last_pfn)
			last_pfn = end_pfn;
	}

	if (last_pfn > max_arch_pfn)
		last_pfn = max_arch_pfn;

	printk(KERN_INFO "e820: last_pfn = %#lx max_arch_pfn = %#lx\n",
			 last_pfn, max_arch_pfn);
	return last_pfn;
}
unsigned long __init e820_end_of_ram_pfn(void)
{
	return e820_end_pfn(MAX_ARCH_PFN, E820_RAM);
}

unsigned long __init e820_end_of_low_ram_pfn(void)
{
	return e820_end_pfn(1UL<<(32 - PAGE_SHIFT), E820_RAM);
}

static void early_panic(char *msg)
{
	early_printk(msg);
	panic(msg);
}

static int userdef __initdata;

/* "mem=nopentium" disables the 4MB page tables. */
static int __init parse_memopt(char *p)
{
	u64 mem_size;

	if (!p)
		return -EINVAL;

	if (!strcmp(p, "nopentium")) {
#ifdef CONFIG_X86_32
		setup_clear_cpu_cap(X86_FEATURE_PSE);
		return 0;
#else
		printk(KERN_WARNING "mem=nopentium ignored! (only supported on x86_32)\n");
		return -EINVAL;
#endif
	}

	userdef = 1;
	mem_size = memparse(p, &p);
	/* don't remove all of memory when handling "mem={invalid}" param */
	if (mem_size == 0)
		return -EINVAL;
	e820_remove_range(mem_size, ULLONG_MAX - mem_size, E820_RAM, 1);

	return 0;
}
early_param("mem", parse_memopt);

static int __init parse_memmap_opt(char *p)
{
	char *oldp;
	u64 start_at, mem_size;

	if (!p)
		return -EINVAL;

	if (!strncmp(p, "exactmap", 8)) {
#ifdef CONFIG_CRASH_DUMP
		/*
		 * If we are doing a crash dump, we still need to know
		 * the real mem size before original memory map is
		 * reset.
		 */
		saved_max_pfn = e820_end_of_ram_pfn();
#endif
		e820.nr_map = 0;
		userdef = 1;
		return 0;
	}

	oldp = p;
	mem_size = memparse(p, &p);
	if (p == oldp)
		return -EINVAL;

	userdef = 1;
	if (*p == '@') {
		start_at = memparse(p+1, &p);
		e820_add_region(start_at, mem_size, E820_RAM);
	} else if (*p == '#') {
		start_at = memparse(p+1, &p);
		e820_add_region(start_at, mem_size, E820_ACPI);
	} else if (*p == '$') {
		start_at = memparse(p+1, &p);
		e820_add_region(start_at, mem_size, E820_RESERVED);
	} else
		e820_remove_range(mem_size, ULLONG_MAX - mem_size, E820_RAM, 1);

	return *p == '\0' ? 0 : -EINVAL;
}
early_param("memmap", parse_memmap_opt);

void __init finish_e820_parsing(void)
{
	if (userdef) {
		u32 nr = e820.nr_map;

		if (sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &nr) < 0)
			early_panic("Invalid user supplied memory map");
		e820.nr_map = nr;

		printk(KERN_INFO "e820: user-defined physical RAM map:\n");
		e820_print_map("user");
	}
}

static inline const char *e820_type_to_string(int e820_type)
{
	switch (e820_type) {
	case E820_RESERVED_KERN:
	case E820_RAM:	return "System RAM";
	case E820_ACPI:	return "ACPI Tables";
	case E820_NVS:	return "ACPI Non-volatile Storage";
	case E820_UNUSABLE:	return "Unusable memory";
	default:	return "reserved";
	}
}

/*
 * Mark e820 reserved areas as busy for the resource manager.
 */
static struct resource __initdata *e820_res;
void __init e820_reserve_resources(void)
{
	int i;
	struct resource *res;
	u64 end;

	res = alloc_bootmem(sizeof(struct resource) * e820.nr_map);
	e820_res = res;
	for (i = 0; i < e820.nr_map; i++) {
		end = e820.map[i].addr + e820.map[i].size - 1;
		if (end != (resource_size_t)end) {
			res++;
			continue;
		}
		res->name = e820_type_to_string(e820.map[i].type);
		res->start = e820.map[i].addr;
		res->end = end;

		res->flags = IORESOURCE_MEM;

		/*
		 * don't register the region that could be conflicted with
		 * pci device BAR resource and insert them later in
		 * pcibios_resource_survey()
		 */
		if (e820.map[i].type != E820_RESERVED || res->start < (1ULL<<20)) {
			res->flags |= IORESOURCE_BUSY;
			insert_resource(&iomem_resource, res);
		}
		res++;
	}

	for (i = 0; i < e820_saved.nr_map; i++) {
		struct e820entry *entry = &e820_saved.map[i];
		firmware_map_add_early(entry->addr,
			entry->addr + entry->size,
			e820_type_to_string(entry->type));
	}
}

/* How much should we pad RAM ending depending on where it is? */
static unsigned long ram_alignment(resource_size_t pos)
{
	unsigned long mb = pos >> 20;

	/* To 64kB in the first megabyte */
	if (!mb)
		return 64*1024;

	/* To 1MB in the first 16MB */
	if (mb < 16)
		return 1024*1024;

	/* To 64MB for anything above that */
	return 64*1024*1024;
}

#define MAX_RESOURCE_SIZE ((resource_size_t)-1)

void __init e820_reserve_resources_late(void)
{
	int i;
	struct resource *res;

	res = e820_res;
	for (i = 0; i < e820.nr_map; i++) {
		if (!res->parent && res->end)
			insert_resource_expand_to_fit(&iomem_resource, res);
		res++;
	}

	/*
	 * Try to bump up RAM regions to reasonable boundaries to
	 * avoid stolen RAM:
	 */
	for (i = 0; i < e820.nr_map; i++) {
		struct e820entry *entry = &e820.map[i];
		u64 start, end;

		if (entry->type != E820_RAM)
			continue;
		start = entry->addr + entry->size;
		end = round_up(start, ram_alignment(start)) - 1;
		if (end > MAX_RESOURCE_SIZE)
			end = MAX_RESOURCE_SIZE;
		if (start >= end)
			continue;
		printk(KERN_DEBUG
		       "e820: reserve RAM buffer [mem %#010llx-%#010llx]\n",
		       start, end);
		reserve_region_with_split(&iomem_resource, start, end,
					  "RAM buffer");
	}
}

char *__init default_machine_specific_memory_setup(void)
{
	char *who = "BIOS-e820";
	u32 new_nr;
	/*
	 * Try to copy the BIOS-supplied E820-map.
	 *
	 * Otherwise fake a memory map; one section from 0k->640k,
	 * the next section from 1mb->appropriate_mem_k
	 */
	new_nr = boot_params.e820_entries;
	sanitize_e820_map(boot_params.e820_map,
			ARRAY_SIZE(boot_params.e820_map),
			&new_nr);
	boot_params.e820_entries = new_nr;
	if (append_e820_map(boot_params.e820_map, boot_params.e820_entries)
	  < 0) {
		u64 mem_size;

		/* compare results from other methods and take the greater */
		if (boot_params.alt_mem_k
		    < boot_params.screen_info.ext_mem_k) {
			mem_size = boot_params.screen_info.ext_mem_k;
			who = "BIOS-88";
		} else {
			mem_size = boot_params.alt_mem_k;
			who = "BIOS-e801";
		}

		e820.nr_map = 0;
		e820_add_region(0, LOWMEMSIZE(), E820_RAM);
		e820_add_region(HIGH_MEMORY, mem_size << 10, E820_RAM);
	}

	/* In case someone cares... */
	return who;
}

void __init setup_memory_map(void)
{
	char *who;

	who = x86_init.resources.memory_setup();
	memcpy(&e820_saved, &e820, sizeof(struct e820map));
	printk(KERN_INFO "e820: BIOS-provided physical RAM map:\n");
	e820_print_map(who);
}

void __init memblock_x86_fill(void)
{
	int i;
	u64 end;

	/*
	 * EFI may have more than 128 entries
	 * We are safe to enable resizing, beause memblock_x86_fill()
	 * is rather later for x86
	 */
	memblock_allow_resize();

	for (i = 0; i < e820.nr_map; i++) {
		struct e820entry *ei = &e820.map[i];

		end = ei->addr + ei->size;
		if (end != (resource_size_t)end)
			continue;

		if (ei->type != E820_RAM && ei->type != E820_RESERVED_KERN)
			continue;

		memblock_add(ei->addr, ei->size);
	}

	memblock_dump_all();
}

void __init memblock_find_dma_reserve(void)
{
#ifdef CONFIG_X86_64
	u64 nr_pages = 0, nr_free_pages = 0;
	unsigned long start_pfn, end_pfn;
	phys_addr_t start, end;
	int i;
	u64 u;

	/*
	 * need to find out used area below MAX_DMA_PFN
	 * need to use memblock to get free size in [0, MAX_DMA_PFN]
	 * at first, and assume boot_mem will not take below MAX_DMA_PFN
	 */
	for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, NULL) {
		start_pfn = min_t(unsigned long, start_pfn, MAX_DMA_PFN);
		end_pfn = min_t(unsigned long, end_pfn, MAX_DMA_PFN);
		nr_pages += end_pfn - start_pfn;
	}

	for_each_free_mem_range(u, MAX_NUMNODES, &start, &end, NULL) {
		start_pfn = min_t(unsigned long, PFN_UP(start), MAX_DMA_PFN);
		end_pfn = min_t(unsigned long, PFN_DOWN(end), MAX_DMA_PFN);
		if (start_pfn < end_pfn)
			nr_free_pages += end_pfn - start_pfn;
	}

	set_dma_reserve(nr_pages - nr_free_pages);
#endif
}