summaryrefslogtreecommitdiffstats
path: root/arch/powerpc/mm/numa.c
blob: 371792e4418fe29d6d9619fb19467b9ed171547f (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
/*
 * pSeries NUMA support
 *
 * Copyright (C) 2002 Anton Blanchard <anton@au.ibm.com>, IBM
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */
#define pr_fmt(fmt) "numa: " fmt

#include <linux/threads.h>
#include <linux/bootmem.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/mmzone.h>
#include <linux/export.h>
#include <linux/nodemask.h>
#include <linux/cpu.h>
#include <linux/notifier.h>
#include <linux/memblock.h>
#include <linux/of.h>
#include <linux/pfn.h>
#include <linux/cpuset.h>
#include <linux/node.h>
#include <linux/stop_machine.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/uaccess.h>
#include <linux/slab.h>
#include <asm/cputhreads.h>
#include <asm/sparsemem.h>
#include <asm/prom.h>
#include <asm/smp.h>
#include <asm/cputhreads.h>
#include <asm/topology.h>
#include <asm/firmware.h>
#include <asm/paca.h>
#include <asm/hvcall.h>
#include <asm/setup.h>
#include <asm/vdso.h>

static int numa_enabled = 1;

static char *cmdline __initdata;

static int numa_debug;
#define dbg(args...) if (numa_debug) { printk(KERN_INFO args); }

int numa_cpu_lookup_table[NR_CPUS];
cpumask_var_t node_to_cpumask_map[MAX_NUMNODES];
struct pglist_data *node_data[MAX_NUMNODES];

EXPORT_SYMBOL(numa_cpu_lookup_table);
EXPORT_SYMBOL(node_to_cpumask_map);
EXPORT_SYMBOL(node_data);

static int min_common_depth;
static int n_mem_addr_cells, n_mem_size_cells;
static int form1_affinity;

#define MAX_DISTANCE_REF_POINTS 4
static int distance_ref_points_depth;
static const __be32 *distance_ref_points;
static int distance_lookup_table[MAX_NUMNODES][MAX_DISTANCE_REF_POINTS];

/*
 * Allocate node_to_cpumask_map based on number of available nodes
 * Requires node_possible_map to be valid.
 *
 * Note: cpumask_of_node() is not valid until after this is done.
 */
static void __init setup_node_to_cpumask_map(void)
{
	unsigned int node;

	/* setup nr_node_ids if not done yet */
	if (nr_node_ids == MAX_NUMNODES)
		setup_nr_node_ids();

	/* allocate the map */
	for_each_node(node)
		alloc_bootmem_cpumask_var(&node_to_cpumask_map[node]);

	/* cpumask_of_node() will now work */
	dbg("Node to cpumask map for %d nodes\n", nr_node_ids);
}

static int __init fake_numa_create_new_node(unsigned long end_pfn,
						unsigned int *nid)
{
	unsigned long long mem;
	char *p = cmdline;
	static unsigned int fake_nid;
	static unsigned long long curr_boundary;

	/*
	 * Modify node id, iff we started creating NUMA nodes
	 * We want to continue from where we left of the last time
	 */
	if (fake_nid)
		*nid = fake_nid;
	/*
	 * In case there are no more arguments to parse, the
	 * node_id should be the same as the last fake node id
	 * (we've handled this above).
	 */
	if (!p)
		return 0;

	mem = memparse(p, &p);
	if (!mem)
		return 0;

	if (mem < curr_boundary)
		return 0;

	curr_boundary = mem;

	if ((end_pfn << PAGE_SHIFT) > mem) {
		/*
		 * Skip commas and spaces
		 */
		while (*p == ',' || *p == ' ' || *p == '\t')
			p++;

		cmdline = p;
		fake_nid++;
		*nid = fake_nid;
		dbg("created new fake_node with id %d\n", fake_nid);
		return 1;
	}
	return 0;
}

static void reset_numa_cpu_lookup_table(void)
{
	unsigned int cpu;

	for_each_possible_cpu(cpu)
		numa_cpu_lookup_table[cpu] = -1;
}

static void update_numa_cpu_lookup_table(unsigned int cpu, int node)
{
	numa_cpu_lookup_table[cpu] = node;
}

static void map_cpu_to_node(int cpu, int node)
{
	update_numa_cpu_lookup_table(cpu, node);

	dbg("adding cpu %d to node %d\n", cpu, node);

	if (!(cpumask_test_cpu(cpu, node_to_cpumask_map[node])))
		cpumask_set_cpu(cpu, node_to_cpumask_map[node]);
}

#if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_PPC_SPLPAR)
static void unmap_cpu_from_node(unsigned long cpu)
{
	int node = numa_cpu_lookup_table[cpu];

	dbg("removing cpu %lu from node %d\n", cpu, node);

	if (cpumask_test_cpu(cpu, node_to_cpumask_map[node])) {
		cpumask_clear_cpu(cpu, node_to_cpumask_map[node]);
	} else {
		printk(KERN_ERR "WARNING: cpu %lu not found in node %d\n",
		       cpu, node);
	}
}
#endif /* CONFIG_HOTPLUG_CPU || CONFIG_PPC_SPLPAR */

/* must hold reference to node during call */
static const __be32 *of_get_associativity(struct device_node *dev)
{
	return of_get_property(dev, "ibm,associativity", NULL);
}

/*
 * Returns the property linux,drconf-usable-memory if
 * it exists (the property exists only in kexec/kdump kernels,
 * added by kexec-tools)
 */
static const __be32 *of_get_usable_memory(struct device_node *memory)
{
	const __be32 *prop;
	u32 len;
	prop = of_get_property(memory, "linux,drconf-usable-memory", &len);
	if (!prop || len < sizeof(unsigned int))
		return NULL;
	return prop;
}

int __node_distance(int a, int b)
{
	int i;
	int distance = LOCAL_DISTANCE;

	if (!form1_affinity)
		return ((a == b) ? LOCAL_DISTANCE : REMOTE_DISTANCE);

	for (i = 0; i < distance_ref_points_depth; i++) {
		if (distance_lookup_table[a][i] == distance_lookup_table[b][i])
			break;

		/* Double the distance for each NUMA level */
		distance *= 2;
	}

	return distance;
}
EXPORT_SYMBOL(__node_distance);

static void initialize_distance_lookup_table(int nid,
		const __be32 *associativity)
{
	int i;

	if (!form1_affinity)
		return;

	for (i = 0; i < distance_ref_points_depth; i++) {
		const __be32 *entry;

		entry = &associativity[be32_to_cpu(distance_ref_points[i]) - 1];
		distance_lookup_table[nid][i] = of_read_number(entry, 1);
	}
}

/* Returns nid in the range [0..MAX_NUMNODES-1], or -1 if no useful numa
 * info is found.
 */
static int associativity_to_nid(const __be32 *associativity)
{
	int nid = -1;

	if (min_common_depth == -1)
		goto out;

	if (of_read_number(associativity, 1) >= min_common_depth)
		nid = of_read_number(&associativity[min_common_depth], 1);

	/* POWER4 LPAR uses 0xffff as invalid node */
	if (nid == 0xffff || nid >= MAX_NUMNODES)
		nid = -1;

	if (nid > 0 &&
		of_read_number(associativity, 1) >= distance_ref_points_depth) {
		/*
		 * Skip the length field and send start of associativity array
		 */
		initialize_distance_lookup_table(nid, associativity + 1);
	}

out:
	return nid;
}

/* Returns the nid associated with the given device tree node,
 * or -1 if not found.
 */
static int of_node_to_nid_single(struct device_node *device)
{
	int nid = -1;
	const __be32 *tmp;

	tmp = of_get_associativity(device);
	if (tmp)
		nid = associativity_to_nid(tmp);
	return nid;
}

/* Walk the device tree upwards, looking for an associativity id */
int of_node_to_nid(struct device_node *device)
{
	int nid = -1;

	of_node_get(device);
	while (device) {
		nid = of_node_to_nid_single(device);
		if (nid != -1)
			break;

		device = of_get_next_parent(device);
	}
	of_node_put(device);

	return nid;
}
EXPORT_SYMBOL(of_node_to_nid);

static int __init find_min_common_depth(void)
{
	int depth;
	struct device_node *root;

	if (firmware_has_feature(FW_FEATURE_OPAL))
		root = of_find_node_by_path("/ibm,opal");
	else
		root = of_find_node_by_path("/rtas");
	if (!root)
		root = of_find_node_by_path("/");

	/*
	 * This property is a set of 32-bit integers, each representing
	 * an index into the ibm,associativity nodes.
	 *
	 * With form 0 affinity the first integer is for an SMP configuration
	 * (should be all 0's) and the second is for a normal NUMA
	 * configuration. We have only one level of NUMA.
	 *
	 * With form 1 affinity the first integer is the most significant
	 * NUMA boundary and the following are progressively less significant
	 * boundaries. There can be more than one level of NUMA.
	 */
	distance_ref_points = of_get_property(root,
					"ibm,associativity-reference-points",
					&distance_ref_points_depth);

	if (!distance_ref_points) {
		dbg("NUMA: ibm,associativity-reference-points not found.\n");
		goto err;
	}

	distance_ref_points_depth /= sizeof(int);

	if (firmware_has_feature(FW_FEATURE_OPAL) ||
	    firmware_has_feature(FW_FEATURE_TYPE1_AFFINITY)) {
		dbg("Using form 1 affinity\n");
		form1_affinity = 1;
	}

	if (form1_affinity) {
		depth = of_read_number(distance_ref_points, 1);
	} else {
		if (distance_ref_points_depth < 2) {
			printk(KERN_WARNING "NUMA: "
				"short ibm,associativity-reference-points\n");
			goto err;
		}

		depth = of_read_number(&distance_ref_points[1], 1);
	}

	/*
	 * Warn and cap if the hardware supports more than
	 * MAX_DISTANCE_REF_POINTS domains.
	 */
	if (distance_ref_points_depth > MAX_DISTANCE_REF_POINTS) {
		printk(KERN_WARNING "NUMA: distance array capped at "
			"%d entries\n", MAX_DISTANCE_REF_POINTS);
		distance_ref_points_depth = MAX_DISTANCE_REF_POINTS;
	}

	of_node_put(root);
	return depth;

err:
	of_node_put(root);
	return -1;
}

static void __init get_n_mem_cells(int *n_addr_cells, int *n_size_cells)
{
	struct device_node *memory = NULL;

	memory = of_find_node_by_type(memory, "memory");
	if (!memory)
		panic("numa.c: No memory nodes found!");

	*n_addr_cells = of_n_addr_cells(memory);
	*n_size_cells = of_n_size_cells(memory);
	of_node_put(memory);
}

static unsigned long read_n_cells(int n, const __be32 **buf)
{
	unsigned long result = 0;

	while (n--) {
		result = (result << 32) | of_read_number(*buf, 1);
		(*buf)++;
	}
	return result;
}

/*
 * Read the next memblock list entry from the ibm,dynamic-memory property
 * and return the information in the provided of_drconf_cell structure.
 */
static void read_drconf_cell(struct of_drconf_cell *drmem, const __be32 **cellp)
{
	const __be32 *cp;

	drmem->base_addr = read_n_cells(n_mem_addr_cells, cellp);

	cp = *cellp;
	drmem->drc_index = of_read_number(cp, 1);
	drmem->reserved = of_read_number(&cp[1], 1);
	drmem->aa_index = of_read_number(&cp[2], 1);
	drmem->flags = of_read_number(&cp[3], 1);

	*cellp = cp + 4;
}

/*
 * Retrieve and validate the ibm,dynamic-memory property of the device tree.
 *
 * The layout of the ibm,dynamic-memory property is a number N of memblock
 * list entries followed by N memblock list entries.  Each memblock list entry
 * contains information as laid out in the of_drconf_cell struct above.
 */
static int of_get_drconf_memory(struct device_node *memory, const __be32 **dm)
{
	const __be32 *prop;
	u32 len, entries;

	prop = of_get_property(memory, "ibm,dynamic-memory", &len);
	if (!prop || len < sizeof(unsigned int))
		return 0;

	entries = of_read_number(prop++, 1);

	/* Now that we know the number of entries, revalidate the size
	 * of the property read in to ensure we have everything
	 */
	if (len < (entries * (n_mem_addr_cells + 4) + 1) * sizeof(unsigned int))
		return 0;

	*dm = prop;
	return entries;
}

/*
 * Retrieve and validate the ibm,lmb-size property for drconf memory
 * from the device tree.
 */
static u64 of_get_lmb_size(struct device_node *memory)
{
	const __be32 *prop;
	u32 len;

	prop = of_get_property(memory, "ibm,lmb-size", &len);
	if (!prop || len < sizeof(unsigned int))
		return 0;

	return read_n_cells(n_mem_size_cells, &prop);
}

struct assoc_arrays {
	u32	n_arrays;
	u32	array_sz;
	const __be32 *arrays;
};

/*
 * Retrieve and validate the list of associativity arrays for drconf
 * memory from the ibm,associativity-lookup-arrays property of the
 * device tree..
 *
 * The layout of the ibm,associativity-lookup-arrays property is a number N
 * indicating the number of associativity arrays, followed by a number M
 * indicating the size of each associativity array, followed by a list
 * of N associativity arrays.
 */
static int of_get_assoc_arrays(struct device_node *memory,
			       struct assoc_arrays *aa)
{
	const __be32 *prop;
	u32 len;

	prop = of_get_property(memory, "ibm,associativity-lookup-arrays", &len);
	if (!prop || len < 2 * sizeof(unsigned int))
		return -1;

	aa->n_arrays = of_read_number(prop++, 1);
	aa->array_sz = of_read_number(prop++, 1);

	/* Now that we know the number of arrays and size of each array,
	 * revalidate the size of the property read in.
	 */
	if (len < (aa->n_arrays * aa->array_sz + 2) * sizeof(unsigned int))
		return -1;

	aa->arrays = prop;
	return 0;
}

/*
 * This is like of_node_to_nid_single() for memory represented in the
 * ibm,dynamic-reconfiguration-memory node.
 */
static int of_drconf_to_nid_single(struct of_drconf_cell *drmem,
				   struct assoc_arrays *aa)
{
	int default_nid = 0;
	int nid = default_nid;
	int index;

	if (min_common_depth > 0 && min_common_depth <= aa->array_sz &&
	    !(drmem->flags & DRCONF_MEM_AI_INVALID) &&
	    drmem->aa_index < aa->n_arrays) {
		index = drmem->aa_index * aa->array_sz + min_common_depth - 1;
		nid = of_read_number(&aa->arrays[index], 1);

		if (nid == 0xffff || nid >= MAX_NUMNODES)
			nid = default_nid;

		if (nid > 0) {
			index = drmem->aa_index * aa->array_sz;
			initialize_distance_lookup_table(nid,
							&aa->arrays[index]);
		}
	}

	return nid;
}

/*
 * Figure out to which domain a cpu belongs and stick it there.
 * Return the id of the domain used.
 */
static int numa_setup_cpu(unsigned long lcpu)
{
	int nid = -1;
	struct device_node *cpu;

	/*
	 * If a valid cpu-to-node mapping is already available, use it
	 * directly instead of querying the firmware, since it represents
	 * the most recent mapping notified to us by the platform (eg: VPHN).
	 */
	if ((nid = numa_cpu_lookup_table[lcpu]) >= 0) {
		map_cpu_to_node(lcpu, nid);
		return nid;
	}

	cpu = of_get_cpu_node(lcpu, NULL);

	if (!cpu) {
		WARN_ON(1);
		if (cpu_present(lcpu))
			goto out_present;
		else
			goto out;
	}

	nid = of_node_to_nid_single(cpu);

out_present:
	if (nid < 0 || !node_online(nid))
		nid = first_online_node;

	map_cpu_to_node(lcpu, nid);
	of_node_put(cpu);
out:
	return nid;
}

static void verify_cpu_node_mapping(int cpu, int node)
{
	int base, sibling, i;

	/* Verify that all the threads in the core belong to the same node */
	base = cpu_first_thread_sibling(cpu);

	for (i = 0; i < threads_per_core; i++) {
		sibling = base + i;

		if (sibling == cpu || cpu_is_offline(sibling))
			continue;

		if (cpu_to_node(sibling) != node) {
			WARN(1, "CPU thread siblings %d and %d don't belong"
				" to the same node!\n", cpu, sibling);
			break;
		}
	}
}

/* Must run before sched domains notifier. */
static int ppc_numa_cpu_prepare(unsigned int cpu)
{
	int nid;

	nid = numa_setup_cpu(cpu);
	verify_cpu_node_mapping(cpu, nid);
	return 0;
}

static int ppc_numa_cpu_dead(unsigned int cpu)
{
#ifdef CONFIG_HOTPLUG_CPU
	unmap_cpu_from_node(cpu);
#endif
	return 0;
}

/*
 * Check and possibly modify a memory region to enforce the memory limit.
 *
 * Returns the size the region should have to enforce the memory limit.
 * This will either be the original value of size, a truncated value,
 * or zero. If the returned value of size is 0 the region should be
 * discarded as it lies wholly above the memory limit.
 */
static unsigned long __init numa_enforce_memory_limit(unsigned long start,
						      unsigned long size)
{
	/*
	 * We use memblock_end_of_DRAM() in here instead of memory_limit because
	 * we've already adjusted it for the limit and it takes care of
	 * having memory holes below the limit.  Also, in the case of
	 * iommu_is_off, memory_limit is not set but is implicitly enforced.
	 */

	if (start + size <= memblock_end_of_DRAM())
		return size;

	if (start >= memblock_end_of_DRAM())
		return 0;

	return memblock_end_of_DRAM() - start;
}

/*
 * Reads the counter for a given entry in
 * linux,drconf-usable-memory property
 */
static inline int __init read_usm_ranges(const __be32 **usm)
{
	/*
	 * For each lmb in ibm,dynamic-memory a corresponding
	 * entry in linux,drconf-usable-memory property contains
	 * a counter followed by that many (base, size) duple.
	 * read the counter from linux,drconf-usable-memory
	 */
	return read_n_cells(n_mem_size_cells, usm);
}

/*
 * Extract NUMA information from the ibm,dynamic-reconfiguration-memory
 * node.  This assumes n_mem_{addr,size}_cells have been set.
 */
static void __init parse_drconf_memory(struct device_node *memory)
{
	const __be32 *uninitialized_var(dm), *usm;
	unsigned int n, rc, ranges, is_kexec_kdump = 0;
	unsigned long lmb_size, base, size, sz;
	int nid;
	struct assoc_arrays aa = { .arrays = NULL };

	n = of_get_drconf_memory(memory, &dm);
	if (!n)
		return;

	lmb_size = of_get_lmb_size(memory);
	if (!lmb_size)
		return;

	rc = of_get_assoc_arrays(memory, &aa);
	if (rc)
		return;

	/* check if this is a kexec/kdump kernel */
	usm = of_get_usable_memory(memory);
	if (usm != NULL)
		is_kexec_kdump = 1;

	for (; n != 0; --n) {
		struct of_drconf_cell drmem;

		read_drconf_cell(&drmem, &dm);

		/* skip this block if the reserved bit is set in flags (0x80)
		   or if the block is not assigned to this partition (0x8) */
		if ((drmem.flags & DRCONF_MEM_RESERVED)
		    || !(drmem.flags & DRCONF_MEM_ASSIGNED))
			continue;

		base = drmem.base_addr;
		size = lmb_size;
		ranges = 1;

		if (is_kexec_kdump) {
			ranges = read_usm_ranges(&usm);
			if (!ranges) /* there are no (base, size) duple */
				continue;
		}
		do {
			if (is_kexec_kdump) {
				base = read_n_cells(n_mem_addr_cells, &usm);
				size = read_n_cells(n_mem_size_cells, &usm);
			}
			nid = of_drconf_to_nid_single(&drmem, &aa);
			fake_numa_create_new_node(
				((base + size) >> PAGE_SHIFT),
					   &nid);
			node_set_online(nid);
			sz = numa_enforce_memory_limit(base, size);
			if (sz)
				memblock_set_node(base, sz,
						  &memblock.memory, nid);
		} while (--ranges);
	}
}

static int __init parse_numa_properties(void)
{
	struct device_node *memory;
	int default_nid = 0;
	unsigned long i;

	if (numa_enabled == 0) {
		printk(KERN_WARNING "NUMA disabled by user\n");
		return -1;
	}

	min_common_depth = find_min_common_depth();

	if (min_common_depth < 0)
		return min_common_depth;

	dbg("NUMA associativity depth for CPU/Memory: %d\n", min_common_depth);

	/*
	 * Even though we connect cpus to numa domains later in SMP
	 * init, we need to know the node ids now. This is because
	 * each node to be onlined must have NODE_DATA etc backing it.
	 */
	for_each_present_cpu(i) {
		struct device_node *cpu;
		int nid;

		cpu = of_get_cpu_node(i, NULL);
		BUG_ON(!cpu);
		nid = of_node_to_nid_single(cpu);
		of_node_put(cpu);

		/*
		 * Don't fall back to default_nid yet -- we will plug
		 * cpus into nodes once the memory scan has discovered
		 * the topology.
		 */
		if (nid < 0)
			continue;
		node_set_online(nid);
	}

	get_n_mem_cells(&n_mem_addr_cells, &n_mem_size_cells);

	for_each_node_by_type(memory, "memory") {
		unsigned long start;
		unsigned long size;
		int nid;
		int ranges;
		const __be32 *memcell_buf;
		unsigned int len;

		memcell_buf = of_get_property(memory,
			"linux,usable-memory", &len);
		if (!memcell_buf || len <= 0)
			memcell_buf = of_get_property(memory, "reg", &len);
		if (!memcell_buf || len <= 0)
			continue;

		/* ranges in cell */
		ranges = (len >> 2) / (n_mem_addr_cells + n_mem_size_cells);
new_range:
		/* these are order-sensitive, and modify the buffer pointer */
		start = read_n_cells(n_mem_addr_cells, &memcell_buf);
		size = read_n_cells(n_mem_size_cells, &memcell_buf);

		/*
		 * Assumption: either all memory nodes or none will
		 * have associativity properties.  If none, then
		 * everything goes to default_nid.
		 */
		nid = of_node_to_nid_single(memory);
		if (nid < 0)
			nid = default_nid;

		fake_numa_create_new_node(((start + size) >> PAGE_SHIFT), &nid);
		node_set_online(nid);

		size = numa_enforce_memory_limit(start, size);
		if (size)
			memblock_set_node(start, size, &memblock.memory, nid);

		if (--ranges)
			goto new_range;
	}

	/*
	 * Now do the same thing for each MEMBLOCK listed in the
	 * ibm,dynamic-memory property in the
	 * ibm,dynamic-reconfiguration-memory node.
	 */
	memory = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory");
	if (memory)
		parse_drconf_memory(memory);

	return 0;
}

static void __init setup_nonnuma(void)
{
	unsigned long top_of_ram = memblock_end_of_DRAM();
	unsigned long total_ram = memblock_phys_mem_size();
	unsigned long start_pfn, end_pfn;
	unsigned int nid = 0;
	struct memblock_region *reg;

	printk(KERN_DEBUG "Top of RAM: 0x%lx, Total RAM: 0x%lx\n",
	       top_of_ram, total_ram);
	printk(KERN_DEBUG "Memory hole size: %ldMB\n",
	       (top_of_ram - total_ram) >> 20);

	for_each_memblock(memory, reg) {
		start_pfn = memblock_region_memory_base_pfn(reg);
		end_pfn = memblock_region_memory_end_pfn(reg);

		fake_numa_create_new_node(end_pfn, &nid);
		memblock_set_node(PFN_PHYS(start_pfn),
				  PFN_PHYS(end_pfn - start_pfn),
				  &memblock.memory, nid);
		node_set_online(nid);
	}
}

void __init dump_numa_cpu_topology(void)
{
	unsigned int node;
	unsigned int cpu, count;

	if (min_common_depth == -1 || !numa_enabled)
		return;

	for_each_online_node(node) {
		pr_info("Node %d CPUs:", node);

		count = 0;
		/*
		 * If we used a CPU iterator here we would miss printing
		 * the holes in the cpumap.
		 */
		for (cpu = 0; cpu < nr_cpu_ids; cpu++) {
			if (cpumask_test_cpu(cpu,
					node_to_cpumask_map[node])) {
				if (count == 0)
					pr_cont(" %u", cpu);
				++count;
			} else {
				if (count > 1)
					pr_cont("-%u", cpu - 1);
				count = 0;
			}
		}

		if (count > 1)
			pr_cont("-%u", nr_cpu_ids - 1);
		pr_cont("\n");
	}
}

/* Initialize NODE_DATA for a node on the local memory */
static void __init setup_node_data(int nid, u64 start_pfn, u64 end_pfn)
{
	u64 spanned_pages = end_pfn - start_pfn;
	const size_t nd_size = roundup(sizeof(pg_data_t), SMP_CACHE_BYTES);
	u64 nd_pa;
	void *nd;
	int tnid;

	nd_pa = memblock_alloc_try_nid(nd_size, SMP_CACHE_BYTES, nid);
	nd = __va(nd_pa);

	/* report and initialize */
	pr_info("  NODE_DATA [mem %#010Lx-%#010Lx]\n",
		nd_pa, nd_pa + nd_size - 1);
	tnid = early_pfn_to_nid(nd_pa >> PAGE_SHIFT);
	if (tnid != nid)
		pr_info("    NODE_DATA(%d) on node %d\n", nid, tnid);

	node_data[nid] = nd;
	memset(NODE_DATA(nid), 0, sizeof(pg_data_t));
	NODE_DATA(nid)->node_id = nid;
	NODE_DATA(nid)->node_start_pfn = start_pfn;
	NODE_DATA(nid)->node_spanned_pages = spanned_pages;
}

void __init initmem_init(void)
{
	int nid, cpu;

	max_low_pfn = memblock_end_of_DRAM() >> PAGE_SHIFT;
	max_pfn = max_low_pfn;

	if (parse_numa_properties())
		setup_nonnuma();

	memblock_dump_all();

	/*
	 * Reduce the possible NUMA nodes to the online NUMA nodes,
	 * since we do not support node hotplug. This ensures that  we
	 * lower the maximum NUMA node ID to what is actually present.
	 */
	nodes_and(node_possible_map, node_possible_map, node_online_map);

	for_each_online_node(nid) {
		unsigned long start_pfn, end_pfn;

		get_pfn_range_for_nid(nid, &start_pfn, &end_pfn);
		setup_node_data(nid, start_pfn, end_pfn);
		sparse_memory_present_with_active_regions(nid);
	}

	sparse_init();

	setup_node_to_cpumask_map();

	reset_numa_cpu_lookup_table();

	/*
	 * We need the numa_cpu_lookup_table to be accurate for all CPUs,
	 * even before we online them, so that we can use cpu_to_{node,mem}
	 * early in boot, cf. smp_prepare_cpus().
	 * _nocalls() + manual invocation is used because cpuhp is not yet
	 * initialized for the boot CPU.
	 */
	cpuhp_setup_state_nocalls(CPUHP_POWER_NUMA_PREPARE, "powerpc/numa:prepare",
				  ppc_numa_cpu_prepare, ppc_numa_cpu_dead);
	for_each_present_cpu(cpu)
		numa_setup_cpu(cpu);
}

static int __init early_numa(char *p)
{
	if (!p)
		return 0;

	if (strstr(p, "off"))
		numa_enabled = 0;

	if (strstr(p, "debug"))
		numa_debug = 1;

	p = strstr(p, "fake=");
	if (p)
		cmdline = p + strlen("fake=");

	return 0;
}
early_param("numa", early_numa);

static bool topology_updates_enabled = true;

static int __init early_topology_updates(char *p)
{
	if (!p)
		return 0;

	if (!strcmp(p, "off")) {
		pr_info("Disabling topology updates\n");
		topology_updates_enabled = false;
	}

	return 0;
}
early_param("topology_updates", early_topology_updates);

#ifdef CONFIG_MEMORY_HOTPLUG
/*
 * Find the node associated with a hot added memory section for
 * memory represented in the device tree by the property
 * ibm,dynamic-reconfiguration-memory/ibm,dynamic-memory.
 */
static int hot_add_drconf_scn_to_nid(struct device_node *memory,
				     unsigned long scn_addr)
{
	const __be32 *dm;
	unsigned int drconf_cell_cnt, rc;
	unsigned long lmb_size;
	struct assoc_arrays aa;
	int nid = -1;

	drconf_cell_cnt = of_get_drconf_memory(memory, &dm);
	if (!drconf_cell_cnt)
		return -1;

	lmb_size = of_get_lmb_size(memory);
	if (!lmb_size)
		return -1;

	rc = of_get_assoc_arrays(memory, &aa);
	if (rc)
		return -1;

	for (; drconf_cell_cnt != 0; --drconf_cell_cnt) {
		struct of_drconf_cell drmem;

		read_drconf_cell(&drmem, &dm);

		/* skip this block if it is reserved or not assigned to
		 * this partition */
		if ((drmem.flags & DRCONF_MEM_RESERVED)
		    || !(drmem.flags & DRCONF_MEM_ASSIGNED))
			continue;

		if ((scn_addr < drmem.base_addr)
		    || (scn_addr >= (drmem.base_addr + lmb_size)))
			continue;

		nid = of_drconf_to_nid_single(&drmem, &aa);
		break;
	}

	return nid;
}

/*
 * Find the node associated with a hot added memory section for memory
 * represented in the device tree as a node (i.e. memory@XXXX) for
 * each memblock.
 */
static int hot_add_node_scn_to_nid(unsigned long scn_addr)
{
	struct device_node *memory;
	int nid = -1;

	for_each_node_by_type(memory, "memory") {
		unsigned long start, size;
		int ranges;
		const __be32 *memcell_buf;
		unsigned int len;

		memcell_buf = of_get_property(memory, "reg", &len);
		if (!memcell_buf || len <= 0)
			continue;

		/* ranges in cell */
		ranges = (len >> 2) / (n_mem_addr_cells + n_mem_size_cells);

		while (ranges--) {
			start = read_n_cells(n_mem_addr_cells, &memcell_buf);
			size = read_n_cells(n_mem_size_cells, &memcell_buf);

			if ((scn_addr < start) || (scn_addr >= (start + size)))
				continue;

			nid = of_node_to_nid_single(memory);
			break;
		}

		if (nid >= 0)
			break;
	}

	of_node_put(memory);

	return nid;
}

/*
 * Find the node associated with a hot added memory section.  Section
 * corresponds to a SPARSEMEM section, not an MEMBLOCK.  It is assumed that
 * sections are fully contained within a single MEMBLOCK.
 */
int hot_add_scn_to_nid(unsigned long scn_addr)
{
	struct device_node *memory = NULL;
	int nid;

	if (!numa_enabled || (min_common_depth < 0))
		return first_online_node;

	memory = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory");
	if (memory) {
		nid = hot_add_drconf_scn_to_nid(memory, scn_addr);
		of_node_put(memory);
	} else {
		nid = hot_add_node_scn_to_nid(scn_addr);
	}

	if (nid < 0 || !node_possible(nid))
		nid = first_online_node;

	return nid;
}

static u64 hot_add_drconf_memory_max(void)
{
	struct device_node *memory = NULL;
	struct device_node *dn = NULL;
	unsigned int drconf_cell_cnt = 0;
	u64 lmb_size = 0;
	const __be32 *dm = NULL;
	const __be64 *lrdr = NULL;
	struct of_drconf_cell drmem;

	dn = of_find_node_by_path("/rtas");
	if (dn) {
		lrdr = of_get_property(dn, "ibm,lrdr-capacity", NULL);
		of_node_put(dn);
		if (lrdr)
			return be64_to_cpup(lrdr);
	}

	memory = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory");
	if (memory) {
		drconf_cell_cnt = of_get_drconf_memory(memory, &dm);
		lmb_size = of_get_lmb_size(memory);

		/* Advance to the last cell, each cell has 6 32 bit integers */
		dm += (drconf_cell_cnt - 1) * 6;
		read_drconf_cell(&drmem, &dm);
		of_node_put(memory);
		return drmem.base_addr + lmb_size;
	}
	return 0;
}

/*
 * memory_hotplug_max - return max address of memory that may be added
 *
 * This is currently only used on systems that support drconfig memory
 * hotplug.
 */
u64 memory_hotplug_max(void)
{
        return max(hot_add_drconf_memory_max(), memblock_end_of_DRAM());
}
#endif /* CONFIG_MEMORY_HOTPLUG */

/* Virtual Processor Home Node (VPHN) support */
#ifdef CONFIG_PPC_SPLPAR

#include "vphn.h"

struct topology_update_data {
	struct topology_update_data *next;
	unsigned int cpu;
	int old_nid;
	int new_nid;
};

static u8 vphn_cpu_change_counts[NR_CPUS][MAX_DISTANCE_REF_POINTS];
static cpumask_t cpu_associativity_changes_mask;
static int vphn_enabled;
static int prrn_enabled;
static void reset_topology_timer(void);

/*
 * Store the current values of the associativity change counters in the
 * hypervisor.
 */
static void setup_cpu_associativity_change_counters(void)
{
	int cpu;

	/* The VPHN feature supports a maximum of 8 reference points */
	BUILD_BUG_ON(MAX_DISTANCE_REF_POINTS > 8);

	for_each_possible_cpu(cpu) {
		int i;
		u8 *counts = vphn_cpu_change_counts[cpu];
		volatile u8 *hypervisor_counts = lppaca[cpu].vphn_assoc_counts;

		for (i = 0; i < distance_ref_points_depth; i++)
			counts[i] = hypervisor_counts[i];
	}
}

/*
 * The hypervisor maintains a set of 8 associativity change counters in
 * the VPA of each cpu that correspond to the associativity levels in the
 * ibm,associativity-reference-points property. When an associativity
 * level changes, the corresponding counter is incremented.
 *
 * Set a bit in cpu_associativity_changes_mask for each cpu whose home
 * node associativity levels have changed.
 *
 * Returns the number of cpus with unhandled associativity changes.
 */
static int update_cpu_associativity_changes_mask(void)
{
	int cpu;
	cpumask_t *changes = &cpu_associativity_changes_mask;

	for_each_possible_cpu(cpu) {
		int i, changed = 0;
		u8 *counts = vphn_cpu_change_counts[cpu];
		volatile u8 *hypervisor_counts = lppaca[cpu].vphn_assoc_counts;

		for (i = 0; i < distance_ref_points_depth; i++) {
			if (hypervisor_counts[i] != counts[i]) {
				counts[i] = hypervisor_counts[i];
				changed = 1;
			}
		}
		if (changed) {
			cpumask_or(changes, changes, cpu_sibling_mask(cpu));
			cpu = cpu_last_thread_sibling(cpu);
		}
	}

	return cpumask_weight(changes);
}

/*
 * Retrieve the new associativity information for a virtual processor's
 * home node.
 */
static long hcall_vphn(unsigned long cpu, __be32 *associativity)
{
	long rc;
	long retbuf[PLPAR_HCALL9_BUFSIZE] = {0};
	u64 flags = 1;
	int hwcpu = get_hard_smp_processor_id(cpu);

	rc = plpar_hcall9(H_HOME_NODE_ASSOCIATIVITY, retbuf, flags, hwcpu);
	vphn_unpack_associativity(retbuf, associativity);

	return rc;
}

static long vphn_get_associativity(unsigned long cpu,
					__be32 *associativity)
{
	long rc;

	rc = hcall_vphn(cpu, associativity);

	switch (rc) {
	case H_FUNCTION:
		printk(KERN_INFO
			"VPHN is not supported. Disabling polling...\n");
		stop_topology_update();
		break;
	case H_HARDWARE:
		printk(KERN_ERR
			"hcall_vphn() experienced a hardware fault "
			"preventing VPHN. Disabling polling...\n");
		stop_topology_update();
	}

	return rc;
}

/*
 * Update the CPU maps and sysfs entries for a single CPU when its NUMA
 * characteristics change. This function doesn't perform any locking and is
 * only safe to call from stop_machine().
 */
static int update_cpu_topology(void *data)
{
	struct topology_update_data *update;
	unsigned long cpu;

	if (!data)
		return -EINVAL;

	cpu = smp_processor_id();

	for (update = data; update; update = update->next) {
		int new_nid = update->new_nid;
		if (cpu != update->cpu)
			continue;

		unmap_cpu_from_node(cpu);
		map_cpu_to_node(cpu, new_nid);
		set_cpu_numa_node(cpu, new_nid);
		set_cpu_numa_mem(cpu, local_memory_node(new_nid));
		vdso_getcpu_init();
	}

	return 0;
}

static int update_lookup_table(void *data)
{
	struct topology_update_data *update;

	if (!data)
		return -EINVAL;

	/*
	 * Upon topology update, the numa-cpu lookup table needs to be updated
	 * for all threads in the core, including offline CPUs, to ensure that
	 * future hotplug operations respect the cpu-to-node associativity
	 * properly.
	 */
	for (update = data; update; update = update->next) {
		int nid, base, j;

		nid = update->new_nid;
		base = cpu_first_thread_sibling(update->cpu);

		for (j = 0; j < threads_per_core; j++) {
			update_numa_cpu_lookup_table(base + j, nid);
		}
	}

	return 0;
}

/*
 * Update the node maps and sysfs entries for each cpu whose home node
 * has changed. Returns 1 when the topology has changed, and 0 otherwise.
 */
int arch_update_cpu_topology(void)
{
	unsigned int cpu, sibling, changed = 0;
	struct topology_update_data *updates, *ud;
	__be32 associativity[VPHN_ASSOC_BUFSIZE] = {0};
	cpumask_t updated_cpus;
	struct device *dev;
	int weight, new_nid, i = 0;

	if (!prrn_enabled && !vphn_enabled)
		return 0;

	weight = cpumask_weight(&cpu_associativity_changes_mask);
	if (!weight)
		return 0;

	updates = kzalloc(weight * (sizeof(*updates)), GFP_KERNEL);
	if (!updates)
		return 0;

	cpumask_clear(&updated_cpus);

	for_each_cpu(cpu, &cpu_associativity_changes_mask) {
		/*
		 * If siblings aren't flagged for changes, updates list
		 * will be too short. Skip on this update and set for next
		 * update.
		 */
		if (!cpumask_subset(cpu_sibling_mask(cpu),
					&cpu_associativity_changes_mask)) {
			pr_info("Sibling bits not set for associativity "
					"change, cpu%d\n", cpu);
			cpumask_or(&cpu_associativity_changes_mask,
					&cpu_associativity_changes_mask,
					cpu_sibling_mask(cpu));
			cpu = cpu_last_thread_sibling(cpu);
			continue;
		}

		/* Use associativity from first thread for all siblings */
		vphn_get_associativity(cpu, associativity);
		new_nid = associativity_to_nid(associativity);
		if (new_nid < 0 || !node_online(new_nid))
			new_nid = first_online_node;

		if (new_nid == numa_cpu_lookup_table[cpu]) {
			cpumask_andnot(&cpu_associativity_changes_mask,
					&cpu_associativity_changes_mask,
					cpu_sibling_mask(cpu));
			cpu = cpu_last_thread_sibling(cpu);
			continue;
		}

		for_each_cpu(sibling, cpu_sibling_mask(cpu)) {
			ud = &updates[i++];
			ud->cpu = sibling;
			ud->new_nid = new_nid;
			ud->old_nid = numa_cpu_lookup_table[sibling];
			cpumask_set_cpu(sibling, &updated_cpus);
			if (i < weight)
				ud->next = &updates[i];
		}
		cpu = cpu_last_thread_sibling(cpu);
	}

	pr_debug("Topology update for the following CPUs:\n");
	if (cpumask_weight(&updated_cpus)) {
		for (ud = &updates[0]; ud; ud = ud->next) {
			pr_debug("cpu %d moving from node %d "
					  "to %d\n", ud->cpu,
					  ud->old_nid, ud->new_nid);
		}
	}

	/*
	 * In cases where we have nothing to update (because the updates list
	 * is too short or because the new topology is same as the old one),
	 * skip invoking update_cpu_topology() via stop-machine(). This is
	 * necessary (and not just a fast-path optimization) since stop-machine
	 * can end up electing a random CPU to run update_cpu_topology(), and
	 * thus trick us into setting up incorrect cpu-node mappings (since
	 * 'updates' is kzalloc()'ed).
	 *
	 * And for the similar reason, we will skip all the following updating.
	 */
	if (!cpumask_weight(&updated_cpus))
		goto out;

	stop_machine(update_cpu_topology, &updates[0], &updated_cpus);

	/*
	 * Update the numa-cpu lookup table with the new mappings, even for
	 * offline CPUs. It is best to perform this update from the stop-
	 * machine context.
	 */
	stop_machine(update_lookup_table, &updates[0],
					cpumask_of(raw_smp_processor_id()));

	for (ud = &updates[0]; ud; ud = ud->next) {
		unregister_cpu_under_node(ud->cpu, ud->old_nid);
		register_cpu_under_node(ud->cpu, ud->new_nid);

		dev = get_cpu_device(ud->cpu);
		if (dev)
			kobject_uevent(&dev->kobj, KOBJ_CHANGE);
		cpumask_clear_cpu(ud->cpu, &cpu_associativity_changes_mask);
		changed = 1;
	}

out:
	kfree(updates);
	return changed;
}

static void topology_work_fn(struct work_struct *work)
{
	rebuild_sched_domains();
}
static DECLARE_WORK(topology_work, topology_work_fn);

static void topology_schedule_update(void)
{
	schedule_work(&topology_work);
}

static void topology_timer_fn(unsigned long ignored)
{
	if (prrn_enabled && cpumask_weight(&cpu_associativity_changes_mask))
		topology_schedule_update();
	else if (vphn_enabled) {
		if (update_cpu_associativity_changes_mask() > 0)
			topology_schedule_update();
		reset_topology_timer();
	}
}
static struct timer_list topology_timer =
	TIMER_INITIALIZER(topology_timer_fn, 0, 0);

static void reset_topology_timer(void)
{
	topology_timer.data = 0;
	topology_timer.expires = jiffies + 60 * HZ;
	mod_timer(&topology_timer, topology_timer.expires);
}

#ifdef CONFIG_SMP

static void stage_topology_update(int core_id)
{
	cpumask_or(&cpu_associativity_changes_mask,
		&cpu_associativity_changes_mask, cpu_sibling_mask(core_id));
	reset_topology_timer();
}

static int dt_update_callback(struct notifier_block *nb,
				unsigned long action, void *data)
{
	struct of_reconfig_data *update = data;
	int rc = NOTIFY_DONE;

	switch (action) {
	case OF_RECONFIG_UPDATE_PROPERTY:
		if (!of_prop_cmp(update->dn->type, "cpu") &&
		    !of_prop_cmp(update->prop->name, "ibm,associativity")) {
			u32 core_id;
			of_property_read_u32(update->dn, "reg", &core_id);
			stage_topology_update(core_id);
			rc = NOTIFY_OK;
		}
		break;
	}

	return rc;
}

static struct notifier_block dt_update_nb = {
	.notifier_call = dt_update_callback,
};

#endif

/*
 * Start polling for associativity changes.
 */
int start_topology_update(void)
{
	int rc = 0;

	if (firmware_has_feature(FW_FEATURE_PRRN)) {
		if (!prrn_enabled) {
			prrn_enabled = 1;
			vphn_enabled = 0;
#ifdef CONFIG_SMP
			rc = of_reconfig_notifier_register(&dt_update_nb);
#endif
		}
	} else if (firmware_has_feature(FW_FEATURE_VPHN) &&
		   lppaca_shared_proc(get_lppaca())) {
		if (!vphn_enabled) {
			prrn_enabled = 0;
			vphn_enabled = 1;
			setup_cpu_associativity_change_counters();
			init_timer_deferrable(&topology_timer);
			reset_topology_timer();
		}
	}

	return rc;
}

/*
 * Disable polling for VPHN associativity changes.
 */
int stop_topology_update(void)
{
	int rc = 0;

	if (prrn_enabled) {
		prrn_enabled = 0;
#ifdef CONFIG_SMP
		rc = of_reconfig_notifier_unregister(&dt_update_nb);
#endif
	} else if (vphn_enabled) {
		vphn_enabled = 0;
		rc = del_timer_sync(&topology_timer);
	}

	return rc;
}

int prrn_is_enabled(void)
{
	return prrn_enabled;
}

static int topology_read(struct seq_file *file, void *v)
{
	if (vphn_enabled || prrn_enabled)
		seq_puts(file, "on\n");
	else
		seq_puts(file, "off\n");

	return 0;
}

static int topology_open(struct inode *inode, struct file *file)
{
	return single_open(file, topology_read, NULL);
}

static ssize_t topology_write(struct file *file, const char __user *buf,
			      size_t count, loff_t *off)
{
	char kbuf[4]; /* "on" or "off" plus null. */
	int read_len;

	read_len = count < 3 ? count : 3;
	if (copy_from_user(kbuf, buf, read_len))
		return -EINVAL;

	kbuf[read_len] = '\0';

	if (!strncmp(kbuf, "on", 2))
		start_topology_update();
	else if (!strncmp(kbuf, "off", 3))
		stop_topology_update();
	else
		return -EINVAL;

	return count;
}

static const struct file_operations topology_ops = {
	.read = seq_read,
	.write = topology_write,
	.open = topology_open,
	.release = single_release
};

static int topology_update_init(void)
{
	/* Do not poll for changes if disabled at boot */
	if (topology_updates_enabled)
		start_topology_update();

	if (!proc_create("powerpc/topology_updates", 0644, NULL, &topology_ops))
		return -ENOMEM;

	return 0;
}
device_initcall(topology_update_init);
#endif /* CONFIG_PPC_SPLPAR */