1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * pSeries NUMA support
4 *
5 * Copyright (C) 2002 Anton Blanchard <anton@au.ibm.com>, IBM
6 */
7#define pr_fmt(fmt) "numa: " fmt
8
9#include <linux/threads.h>
10#include <linux/memblock.h>
11#include <linux/init.h>
12#include <linux/mm.h>
13#include <linux/mmzone.h>
14#include <linux/export.h>
15#include <linux/nodemask.h>
16#include <linux/cpu.h>
17#include <linux/notifier.h>
18#include <linux/of.h>
19#include <linux/of_address.h>
20#include <linux/pfn.h>
21#include <linux/cpuset.h>
22#include <linux/node.h>
23#include <linux/stop_machine.h>
24#include <linux/proc_fs.h>
25#include <linux/seq_file.h>
26#include <linux/uaccess.h>
27#include <linux/slab.h>
28#include <asm/cputhreads.h>
29#include <asm/sparsemem.h>
30#include <asm/smp.h>
31#include <asm/topology.h>
32#include <asm/firmware.h>
33#include <asm/paca.h>
34#include <asm/hvcall.h>
35#include <asm/setup.h>
36#include <asm/vdso.h>
37#include <asm/vphn.h>
38#include <asm/drmem.h>
39
40static int numa_enabled = 1;
41
42static char *cmdline __initdata;
43
44int numa_cpu_lookup_table[NR_CPUS];
45cpumask_var_t node_to_cpumask_map[MAX_NUMNODES];
46struct pglist_data *node_data[MAX_NUMNODES];
47
48EXPORT_SYMBOL(numa_cpu_lookup_table);
49EXPORT_SYMBOL(node_to_cpumask_map);
50EXPORT_SYMBOL(node_data);
51
52static int primary_domain_index;
53static int n_mem_addr_cells, n_mem_size_cells;
54
55#define FORM0_AFFINITY 0
56#define FORM1_AFFINITY 1
57#define FORM2_AFFINITY 2
58static int affinity_form;
59
60#define MAX_DISTANCE_REF_POINTS 4
61static int distance_ref_points_depth;
62static const __be32 *distance_ref_points;
63static int distance_lookup_table[MAX_NUMNODES][MAX_DISTANCE_REF_POINTS];
64static int numa_distance_table[MAX_NUMNODES][MAX_NUMNODES] = {
65 [0 ... MAX_NUMNODES - 1] = { [0 ... MAX_NUMNODES - 1] = -1 }
66};
67static int numa_id_index_table[MAX_NUMNODES] = { [0 ... MAX_NUMNODES - 1] = NUMA_NO_NODE };
68
69/*
70 * Allocate node_to_cpumask_map based on number of available nodes
71 * Requires node_possible_map to be valid.
72 *
73 * Note: cpumask_of_node() is not valid until after this is done.
74 */
75static void __init setup_node_to_cpumask_map(void)
76{
77 unsigned int node;
78
79 /* setup nr_node_ids if not done yet */
80 if (nr_node_ids == MAX_NUMNODES)
81 setup_nr_node_ids();
82
83 /* allocate the map */
84 for_each_node(node)
85 alloc_bootmem_cpumask_var(mask: &node_to_cpumask_map[node]);
86
87 /* cpumask_of_node() will now work */
88 pr_debug("Node to cpumask map for %u nodes\n", nr_node_ids);
89}
90
91static int __init fake_numa_create_new_node(unsigned long end_pfn,
92 unsigned int *nid)
93{
94 unsigned long long mem;
95 char *p = cmdline;
96 static unsigned int fake_nid;
97 static unsigned long long curr_boundary;
98
99 /*
100 * Modify node id, iff we started creating NUMA nodes
101 * We want to continue from where we left of the last time
102 */
103 if (fake_nid)
104 *nid = fake_nid;
105 /*
106 * In case there are no more arguments to parse, the
107 * node_id should be the same as the last fake node id
108 * (we've handled this above).
109 */
110 if (!p)
111 return 0;
112
113 mem = memparse(ptr: p, retptr: &p);
114 if (!mem)
115 return 0;
116
117 if (mem < curr_boundary)
118 return 0;
119
120 curr_boundary = mem;
121
122 if ((end_pfn << PAGE_SHIFT) > mem) {
123 /*
124 * Skip commas and spaces
125 */
126 while (*p == ',' || *p == ' ' || *p == '\t')
127 p++;
128
129 cmdline = p;
130 fake_nid++;
131 *nid = fake_nid;
132 pr_debug("created new fake_node with id %d\n", fake_nid);
133 return 1;
134 }
135 return 0;
136}
137
138static void __init reset_numa_cpu_lookup_table(void)
139{
140 unsigned int cpu;
141
142 for_each_possible_cpu(cpu)
143 numa_cpu_lookup_table[cpu] = -1;
144}
145
146void map_cpu_to_node(int cpu, int node)
147{
148 update_numa_cpu_lookup_table(cpu, node);
149
150 if (!(cpumask_test_cpu(cpu, cpumask: node_to_cpumask_map[node]))) {
151 pr_debug("adding cpu %d to node %d\n", cpu, node);
152 cpumask_set_cpu(cpu, dstp: node_to_cpumask_map[node]);
153 }
154}
155
156#if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_PPC_SPLPAR)
157void unmap_cpu_from_node(unsigned long cpu)
158{
159 int node = numa_cpu_lookup_table[cpu];
160
161 if (cpumask_test_cpu(cpu, cpumask: node_to_cpumask_map[node])) {
162 cpumask_clear_cpu(cpu, dstp: node_to_cpumask_map[node]);
163 pr_debug("removing cpu %lu from node %d\n", cpu, node);
164 } else {
165 pr_warn("Warning: cpu %lu not found in node %d\n", cpu, node);
166 }
167}
168#endif /* CONFIG_HOTPLUG_CPU || CONFIG_PPC_SPLPAR */
169
170static int __associativity_to_nid(const __be32 *associativity,
171 int max_array_sz)
172{
173 int nid;
174 /*
175 * primary_domain_index is 1 based array index.
176 */
177 int index = primary_domain_index - 1;
178
179 if (!numa_enabled || index >= max_array_sz)
180 return NUMA_NO_NODE;
181
182 nid = of_read_number(cell: &associativity[index], size: 1);
183
184 /* POWER4 LPAR uses 0xffff as invalid node */
185 if (nid == 0xffff || nid >= nr_node_ids)
186 nid = NUMA_NO_NODE;
187 return nid;
188}
189/*
190 * Returns nid in the range [0..nr_node_ids], or -1 if no useful NUMA
191 * info is found.
192 */
193static int associativity_to_nid(const __be32 *associativity)
194{
195 int array_sz = of_read_number(cell: associativity, size: 1);
196
197 /* Skip the first element in the associativity array */
198 return __associativity_to_nid(associativity: (associativity + 1), max_array_sz: array_sz);
199}
200
201static int __cpu_form2_relative_distance(__be32 *cpu1_assoc, __be32 *cpu2_assoc)
202{
203 int dist;
204 int node1, node2;
205
206 node1 = associativity_to_nid(associativity: cpu1_assoc);
207 node2 = associativity_to_nid(associativity: cpu2_assoc);
208
209 dist = numa_distance_table[node1][node2];
210 if (dist <= LOCAL_DISTANCE)
211 return 0;
212 else if (dist <= REMOTE_DISTANCE)
213 return 1;
214 else
215 return 2;
216}
217
218static int __cpu_form1_relative_distance(__be32 *cpu1_assoc, __be32 *cpu2_assoc)
219{
220 int dist = 0;
221
222 int i, index;
223
224 for (i = 0; i < distance_ref_points_depth; i++) {
225 index = be32_to_cpu(distance_ref_points[i]);
226 if (cpu1_assoc[index] == cpu2_assoc[index])
227 break;
228 dist++;
229 }
230
231 return dist;
232}
233
234int cpu_relative_distance(__be32 *cpu1_assoc, __be32 *cpu2_assoc)
235{
236 /* We should not get called with FORM0 */
237 VM_WARN_ON(affinity_form == FORM0_AFFINITY);
238 if (affinity_form == FORM1_AFFINITY)
239 return __cpu_form1_relative_distance(cpu1_assoc, cpu2_assoc);
240 return __cpu_form2_relative_distance(cpu1_assoc, cpu2_assoc);
241}
242
243/* must hold reference to node during call */
244static const __be32 *of_get_associativity(struct device_node *dev)
245{
246 return of_get_property(node: dev, name: "ibm,associativity", NULL);
247}
248
249int __node_distance(int a, int b)
250{
251 int i;
252 int distance = LOCAL_DISTANCE;
253
254 if (affinity_form == FORM2_AFFINITY)
255 return numa_distance_table[a][b];
256 else if (affinity_form == FORM0_AFFINITY)
257 return ((a == b) ? LOCAL_DISTANCE : REMOTE_DISTANCE);
258
259 for (i = 0; i < distance_ref_points_depth; i++) {
260 if (distance_lookup_table[a][i] == distance_lookup_table[b][i])
261 break;
262
263 /* Double the distance for each NUMA level */
264 distance *= 2;
265 }
266
267 return distance;
268}
269EXPORT_SYMBOL(__node_distance);
270
271/* Returns the nid associated with the given device tree node,
272 * or -1 if not found.
273 */
274static int of_node_to_nid_single(struct device_node *device)
275{
276 int nid = NUMA_NO_NODE;
277 const __be32 *tmp;
278
279 tmp = of_get_associativity(dev: device);
280 if (tmp)
281 nid = associativity_to_nid(associativity: tmp);
282 return nid;
283}
284
285/* Walk the device tree upwards, looking for an associativity id */
286int of_node_to_nid(struct device_node *device)
287{
288 int nid = NUMA_NO_NODE;
289
290 of_node_get(node: device);
291 while (device) {
292 nid = of_node_to_nid_single(device);
293 if (nid != -1)
294 break;
295
296 device = of_get_next_parent(node: device);
297 }
298 of_node_put(node: device);
299
300 return nid;
301}
302EXPORT_SYMBOL(of_node_to_nid);
303
304static void __initialize_form1_numa_distance(const __be32 *associativity,
305 int max_array_sz)
306{
307 int i, nid;
308
309 if (affinity_form != FORM1_AFFINITY)
310 return;
311
312 nid = __associativity_to_nid(associativity, max_array_sz);
313 if (nid != NUMA_NO_NODE) {
314 for (i = 0; i < distance_ref_points_depth; i++) {
315 const __be32 *entry;
316 int index = be32_to_cpu(distance_ref_points[i]) - 1;
317
318 /*
319 * broken hierarchy, return with broken distance table
320 */
321 if (WARN(index >= max_array_sz, "Broken ibm,associativity property"))
322 return;
323
324 entry = &associativity[index];
325 distance_lookup_table[nid][i] = of_read_number(cell: entry, size: 1);
326 }
327 }
328}
329
330static void initialize_form1_numa_distance(const __be32 *associativity)
331{
332 int array_sz;
333
334 array_sz = of_read_number(cell: associativity, size: 1);
335 /* Skip the first element in the associativity array */
336 __initialize_form1_numa_distance(associativity: associativity + 1, max_array_sz: array_sz);
337}
338
339/*
340 * Used to update distance information w.r.t newly added node.
341 */
342void update_numa_distance(struct device_node *node)
343{
344 int nid;
345
346 if (affinity_form == FORM0_AFFINITY)
347 return;
348 else if (affinity_form == FORM1_AFFINITY) {
349 const __be32 *associativity;
350
351 associativity = of_get_associativity(dev: node);
352 if (!associativity)
353 return;
354
355 initialize_form1_numa_distance(associativity);
356 return;
357 }
358
359 /* FORM2 affinity */
360 nid = of_node_to_nid_single(device: node);
361 if (nid == NUMA_NO_NODE)
362 return;
363
364 /*
365 * With FORM2 we expect NUMA distance of all possible NUMA
366 * nodes to be provided during boot.
367 */
368 WARN(numa_distance_table[nid][nid] == -1,
369 "NUMA distance details for node %d not provided\n", nid);
370}
371EXPORT_SYMBOL_GPL(update_numa_distance);
372
373/*
374 * ibm,numa-lookup-index-table= {N, domainid1, domainid2, ..... domainidN}
375 * ibm,numa-distance-table = { N, 1, 2, 4, 5, 1, 6, .... N elements}
376 */
377static void __init initialize_form2_numa_distance_lookup_table(void)
378{
379 int i, j;
380 struct device_node *root;
381 const __u8 *form2_distances;
382 const __be32 *numa_lookup_index;
383 int form2_distances_length;
384 int max_numa_index, distance_index;
385
386 if (firmware_has_feature(FW_FEATURE_OPAL))
387 root = of_find_node_by_path(path: "/ibm,opal");
388 else
389 root = of_find_node_by_path(path: "/rtas");
390 if (!root)
391 root = of_find_node_by_path(path: "/");
392
393 numa_lookup_index = of_get_property(node: root, name: "ibm,numa-lookup-index-table", NULL);
394 max_numa_index = of_read_number(cell: &numa_lookup_index[0], size: 1);
395
396 /* first element of the array is the size and is encode-int */
397 form2_distances = of_get_property(node: root, name: "ibm,numa-distance-table", NULL);
398 form2_distances_length = of_read_number(cell: (const __be32 *)&form2_distances[0], size: 1);
399 /* Skip the size which is encoded int */
400 form2_distances += sizeof(__be32);
401
402 pr_debug("form2_distances_len = %d, numa_dist_indexes_len = %d\n",
403 form2_distances_length, max_numa_index);
404
405 for (i = 0; i < max_numa_index; i++)
406 /* +1 skip the max_numa_index in the property */
407 numa_id_index_table[i] = of_read_number(cell: &numa_lookup_index[i + 1], size: 1);
408
409
410 if (form2_distances_length != max_numa_index * max_numa_index) {
411 WARN(1, "Wrong NUMA distance information\n");
412 form2_distances = NULL; // don't use it
413 }
414 distance_index = 0;
415 for (i = 0; i < max_numa_index; i++) {
416 for (j = 0; j < max_numa_index; j++) {
417 int nodeA = numa_id_index_table[i];
418 int nodeB = numa_id_index_table[j];
419 int dist;
420
421 if (form2_distances)
422 dist = form2_distances[distance_index++];
423 else if (nodeA == nodeB)
424 dist = LOCAL_DISTANCE;
425 else
426 dist = REMOTE_DISTANCE;
427 numa_distance_table[nodeA][nodeB] = dist;
428 pr_debug("dist[%d][%d]=%d ", nodeA, nodeB, dist);
429 }
430 }
431
432 of_node_put(node: root);
433}
434
435static int __init find_primary_domain_index(void)
436{
437 int index;
438 struct device_node *root;
439
440 /*
441 * Check for which form of affinity.
442 */
443 if (firmware_has_feature(FW_FEATURE_OPAL)) {
444 affinity_form = FORM1_AFFINITY;
445 } else if (firmware_has_feature(FW_FEATURE_FORM2_AFFINITY)) {
446 pr_debug("Using form 2 affinity\n");
447 affinity_form = FORM2_AFFINITY;
448 } else if (firmware_has_feature(FW_FEATURE_FORM1_AFFINITY)) {
449 pr_debug("Using form 1 affinity\n");
450 affinity_form = FORM1_AFFINITY;
451 } else
452 affinity_form = FORM0_AFFINITY;
453
454 if (firmware_has_feature(FW_FEATURE_OPAL))
455 root = of_find_node_by_path(path: "/ibm,opal");
456 else
457 root = of_find_node_by_path(path: "/rtas");
458 if (!root)
459 root = of_find_node_by_path(path: "/");
460
461 /*
462 * This property is a set of 32-bit integers, each representing
463 * an index into the ibm,associativity nodes.
464 *
465 * With form 0 affinity the first integer is for an SMP configuration
466 * (should be all 0's) and the second is for a normal NUMA
467 * configuration. We have only one level of NUMA.
468 *
469 * With form 1 affinity the first integer is the most significant
470 * NUMA boundary and the following are progressively less significant
471 * boundaries. There can be more than one level of NUMA.
472 */
473 distance_ref_points = of_get_property(node: root,
474 name: "ibm,associativity-reference-points",
475 lenp: &distance_ref_points_depth);
476
477 if (!distance_ref_points) {
478 pr_debug("ibm,associativity-reference-points not found.\n");
479 goto err;
480 }
481
482 distance_ref_points_depth /= sizeof(int);
483 if (affinity_form == FORM0_AFFINITY) {
484 if (distance_ref_points_depth < 2) {
485 pr_warn("short ibm,associativity-reference-points\n");
486 goto err;
487 }
488
489 index = of_read_number(cell: &distance_ref_points[1], size: 1);
490 } else {
491 /*
492 * Both FORM1 and FORM2 affinity find the primary domain details
493 * at the same offset.
494 */
495 index = of_read_number(cell: distance_ref_points, size: 1);
496 }
497 /*
498 * Warn and cap if the hardware supports more than
499 * MAX_DISTANCE_REF_POINTS domains.
500 */
501 if (distance_ref_points_depth > MAX_DISTANCE_REF_POINTS) {
502 pr_warn("distance array capped at %d entries\n",
503 MAX_DISTANCE_REF_POINTS);
504 distance_ref_points_depth = MAX_DISTANCE_REF_POINTS;
505 }
506
507 of_node_put(node: root);
508 return index;
509
510err:
511 of_node_put(node: root);
512 return -1;
513}
514
515static void __init get_n_mem_cells(int *n_addr_cells, int *n_size_cells)
516{
517 struct device_node *memory = NULL;
518
519 memory = of_find_node_by_type(from: memory, type: "memory");
520 if (!memory)
521 panic(fmt: "numa.c: No memory nodes found!");
522
523 *n_addr_cells = of_n_addr_cells(np: memory);
524 *n_size_cells = of_n_size_cells(np: memory);
525 of_node_put(node: memory);
526}
527
528static unsigned long read_n_cells(int n, const __be32 **buf)
529{
530 unsigned long result = 0;
531
532 while (n--) {
533 result = (result << 32) | of_read_number(cell: *buf, size: 1);
534 (*buf)++;
535 }
536 return result;
537}
538
539struct assoc_arrays {
540 u32 n_arrays;
541 u32 array_sz;
542 const __be32 *arrays;
543};
544
545/*
546 * Retrieve and validate the list of associativity arrays for drconf
547 * memory from the ibm,associativity-lookup-arrays property of the
548 * device tree..
549 *
550 * The layout of the ibm,associativity-lookup-arrays property is a number N
551 * indicating the number of associativity arrays, followed by a number M
552 * indicating the size of each associativity array, followed by a list
553 * of N associativity arrays.
554 */
555static int of_get_assoc_arrays(struct assoc_arrays *aa)
556{
557 struct device_node *memory;
558 const __be32 *prop;
559 u32 len;
560
561 memory = of_find_node_by_path(path: "/ibm,dynamic-reconfiguration-memory");
562 if (!memory)
563 return -1;
564
565 prop = of_get_property(node: memory, name: "ibm,associativity-lookup-arrays", lenp: &len);
566 if (!prop || len < 2 * sizeof(unsigned int)) {
567 of_node_put(node: memory);
568 return -1;
569 }
570
571 aa->n_arrays = of_read_number(cell: prop++, size: 1);
572 aa->array_sz = of_read_number(cell: prop++, size: 1);
573
574 of_node_put(node: memory);
575
576 /* Now that we know the number of arrays and size of each array,
577 * revalidate the size of the property read in.
578 */
579 if (len < (aa->n_arrays * aa->array_sz + 2) * sizeof(unsigned int))
580 return -1;
581
582 aa->arrays = prop;
583 return 0;
584}
585
586static int __init get_nid_and_numa_distance(struct drmem_lmb *lmb)
587{
588 struct assoc_arrays aa = { .arrays = NULL };
589 int default_nid = NUMA_NO_NODE;
590 int nid = default_nid;
591 int rc, index;
592
593 if ((primary_domain_index < 0) || !numa_enabled)
594 return default_nid;
595
596 rc = of_get_assoc_arrays(aa: &aa);
597 if (rc)
598 return default_nid;
599
600 if (primary_domain_index <= aa.array_sz &&
601 !(lmb->flags & DRCONF_MEM_AI_INVALID) && lmb->aa_index < aa.n_arrays) {
602 const __be32 *associativity;
603
604 index = lmb->aa_index * aa.array_sz;
605 associativity = &aa.arrays[index];
606 nid = __associativity_to_nid(associativity, max_array_sz: aa.array_sz);
607 if (nid > 0 && affinity_form == FORM1_AFFINITY) {
608 /*
609 * lookup array associativity entries have
610 * no length of the array as the first element.
611 */
612 __initialize_form1_numa_distance(associativity, max_array_sz: aa.array_sz);
613 }
614 }
615 return nid;
616}
617
618/*
619 * This is like of_node_to_nid_single() for memory represented in the
620 * ibm,dynamic-reconfiguration-memory node.
621 */
622int of_drconf_to_nid_single(struct drmem_lmb *lmb)
623{
624 struct assoc_arrays aa = { .arrays = NULL };
625 int default_nid = NUMA_NO_NODE;
626 int nid = default_nid;
627 int rc, index;
628
629 if ((primary_domain_index < 0) || !numa_enabled)
630 return default_nid;
631
632 rc = of_get_assoc_arrays(aa: &aa);
633 if (rc)
634 return default_nid;
635
636 if (primary_domain_index <= aa.array_sz &&
637 !(lmb->flags & DRCONF_MEM_AI_INVALID) && lmb->aa_index < aa.n_arrays) {
638 const __be32 *associativity;
639
640 index = lmb->aa_index * aa.array_sz;
641 associativity = &aa.arrays[index];
642 nid = __associativity_to_nid(associativity, max_array_sz: aa.array_sz);
643 }
644 return nid;
645}
646
647#ifdef CONFIG_PPC_SPLPAR
648
649static int __vphn_get_associativity(long lcpu, __be32 *associativity)
650{
651 long rc, hwid;
652
653 /*
654 * On a shared lpar, device tree will not have node associativity.
655 * At this time lppaca, or its __old_status field may not be
656 * updated. Hence kernel cannot detect if its on a shared lpar. So
657 * request an explicit associativity irrespective of whether the
658 * lpar is shared or dedicated. Use the device tree property as a
659 * fallback. cpu_to_phys_id is only valid between
660 * smp_setup_cpu_maps() and smp_setup_pacas().
661 */
662 if (firmware_has_feature(FW_FEATURE_VPHN)) {
663 if (cpu_to_phys_id)
664 hwid = cpu_to_phys_id[lcpu];
665 else
666 hwid = get_hard_smp_processor_id(lcpu);
667
668 rc = hcall_vphn(hwid, VPHN_FLAG_VCPU, associativity);
669 if (rc == H_SUCCESS)
670 return 0;
671 }
672
673 return -1;
674}
675
676static int vphn_get_nid(long lcpu)
677{
678 __be32 associativity[VPHN_ASSOC_BUFSIZE] = {0};
679
680
681 if (!__vphn_get_associativity(lcpu, associativity))
682 return associativity_to_nid(associativity);
683
684 return NUMA_NO_NODE;
685
686}
687#else
688
689static int __vphn_get_associativity(long lcpu, __be32 *associativity)
690{
691 return -1;
692}
693
694static int vphn_get_nid(long unused)
695{
696 return NUMA_NO_NODE;
697}
698#endif /* CONFIG_PPC_SPLPAR */
699
700/*
701 * Figure out to which domain a cpu belongs and stick it there.
702 * Return the id of the domain used.
703 */
704static int numa_setup_cpu(unsigned long lcpu)
705{
706 struct device_node *cpu;
707 int fcpu = cpu_first_thread_sibling(lcpu);
708 int nid = NUMA_NO_NODE;
709
710 if (!cpu_present(cpu: lcpu)) {
711 set_cpu_numa_node(cpu: lcpu, first_online_node);
712 return first_online_node;
713 }
714
715 /*
716 * If a valid cpu-to-node mapping is already available, use it
717 * directly instead of querying the firmware, since it represents
718 * the most recent mapping notified to us by the platform (eg: VPHN).
719 * Since cpu_to_node binding remains the same for all threads in the
720 * core. If a valid cpu-to-node mapping is already available, for
721 * the first thread in the core, use it.
722 */
723 nid = numa_cpu_lookup_table[fcpu];
724 if (nid >= 0) {
725 map_cpu_to_node(cpu: lcpu, node: nid);
726 return nid;
727 }
728
729 nid = vphn_get_nid(unused: lcpu);
730 if (nid != NUMA_NO_NODE)
731 goto out_present;
732
733 cpu = of_get_cpu_node(cpu: lcpu, NULL);
734
735 if (!cpu) {
736 WARN_ON(1);
737 if (cpu_present(cpu: lcpu))
738 goto out_present;
739 else
740 goto out;
741 }
742
743 nid = of_node_to_nid_single(device: cpu);
744 of_node_put(node: cpu);
745
746out_present:
747 if (nid < 0 || !node_possible(nid))
748 nid = first_online_node;
749
750 /*
751 * Update for the first thread of the core. All threads of a core
752 * have to be part of the same node. This not only avoids querying
753 * for every other thread in the core, but always avoids a case
754 * where virtual node associativity change causes subsequent threads
755 * of a core to be associated with different nid. However if first
756 * thread is already online, expect it to have a valid mapping.
757 */
758 if (fcpu != lcpu) {
759 WARN_ON(cpu_online(fcpu));
760 map_cpu_to_node(cpu: fcpu, node: nid);
761 }
762
763 map_cpu_to_node(cpu: lcpu, node: nid);
764out:
765 return nid;
766}
767
768static void verify_cpu_node_mapping(int cpu, int node)
769{
770 int base, sibling, i;
771
772 /* Verify that all the threads in the core belong to the same node */
773 base = cpu_first_thread_sibling(cpu);
774
775 for (i = 0; i < threads_per_core; i++) {
776 sibling = base + i;
777
778 if (sibling == cpu || cpu_is_offline(sibling))
779 continue;
780
781 if (cpu_to_node(cpu: sibling) != node) {
782 WARN(1, "CPU thread siblings %d and %d don't belong"
783 " to the same node!\n", cpu, sibling);
784 break;
785 }
786 }
787}
788
789/* Must run before sched domains notifier. */
790static int ppc_numa_cpu_prepare(unsigned int cpu)
791{
792 int nid;
793
794 nid = numa_setup_cpu(lcpu: cpu);
795 verify_cpu_node_mapping(cpu, node: nid);
796 return 0;
797}
798
799static int ppc_numa_cpu_dead(unsigned int cpu)
800{
801 return 0;
802}
803
804/*
805 * Check and possibly modify a memory region to enforce the memory limit.
806 *
807 * Returns the size the region should have to enforce the memory limit.
808 * This will either be the original value of size, a truncated value,
809 * or zero. If the returned value of size is 0 the region should be
810 * discarded as it lies wholly above the memory limit.
811 */
812static unsigned long __init numa_enforce_memory_limit(unsigned long start,
813 unsigned long size)
814{
815 /*
816 * We use memblock_end_of_DRAM() in here instead of memory_limit because
817 * we've already adjusted it for the limit and it takes care of
818 * having memory holes below the limit. Also, in the case of
819 * iommu_is_off, memory_limit is not set but is implicitly enforced.
820 */
821
822 if (start + size <= memblock_end_of_DRAM())
823 return size;
824
825 if (start >= memblock_end_of_DRAM())
826 return 0;
827
828 return memblock_end_of_DRAM() - start;
829}
830
831/*
832 * Reads the counter for a given entry in
833 * linux,drconf-usable-memory property
834 */
835static inline int __init read_usm_ranges(const __be32 **usm)
836{
837 /*
838 * For each lmb in ibm,dynamic-memory a corresponding
839 * entry in linux,drconf-usable-memory property contains
840 * a counter followed by that many (base, size) duple.
841 * read the counter from linux,drconf-usable-memory
842 */
843 return read_n_cells(n: n_mem_size_cells, buf: usm);
844}
845
846/*
847 * Extract NUMA information from the ibm,dynamic-reconfiguration-memory
848 * node. This assumes n_mem_{addr,size}_cells have been set.
849 */
850static int __init numa_setup_drmem_lmb(struct drmem_lmb *lmb,
851 const __be32 **usm,
852 void *data)
853{
854 unsigned int ranges, is_kexec_kdump = 0;
855 unsigned long base, size, sz;
856 int nid;
857
858 /*
859 * Skip this block if the reserved bit is set in flags (0x80)
860 * or if the block is not assigned to this partition (0x8)
861 */
862 if ((lmb->flags & DRCONF_MEM_RESERVED)
863 || !(lmb->flags & DRCONF_MEM_ASSIGNED))
864 return 0;
865
866 if (*usm)
867 is_kexec_kdump = 1;
868
869 base = lmb->base_addr;
870 size = drmem_lmb_size();
871 ranges = 1;
872
873 if (is_kexec_kdump) {
874 ranges = read_usm_ranges(usm);
875 if (!ranges) /* there are no (base, size) duple */
876 return 0;
877 }
878
879 do {
880 if (is_kexec_kdump) {
881 base = read_n_cells(n: n_mem_addr_cells, buf: usm);
882 size = read_n_cells(n: n_mem_size_cells, buf: usm);
883 }
884
885 nid = get_nid_and_numa_distance(lmb);
886 fake_numa_create_new_node(end_pfn: ((base + size) >> PAGE_SHIFT),
887 nid: &nid);
888 node_set_online(nid);
889 sz = numa_enforce_memory_limit(start: base, size);
890 if (sz)
891 memblock_set_node(base, size: sz, type: &memblock.memory, nid);
892 } while (--ranges);
893
894 return 0;
895}
896
897static int __init parse_numa_properties(void)
898{
899 struct device_node *memory;
900 int default_nid = 0;
901 unsigned long i;
902 const __be32 *associativity;
903
904 if (numa_enabled == 0) {
905 pr_warn("disabled by user\n");
906 return -1;
907 }
908
909 primary_domain_index = find_primary_domain_index();
910
911 if (primary_domain_index < 0) {
912 /*
913 * if we fail to parse primary_domain_index from device tree
914 * mark the numa disabled, boot with numa disabled.
915 */
916 numa_enabled = false;
917 return primary_domain_index;
918 }
919
920 pr_debug("associativity depth for CPU/Memory: %d\n", primary_domain_index);
921
922 /*
923 * If it is FORM2 initialize the distance table here.
924 */
925 if (affinity_form == FORM2_AFFINITY)
926 initialize_form2_numa_distance_lookup_table();
927
928 /*
929 * Even though we connect cpus to numa domains later in SMP
930 * init, we need to know the node ids now. This is because
931 * each node to be onlined must have NODE_DATA etc backing it.
932 */
933 for_each_present_cpu(i) {
934 __be32 vphn_assoc[VPHN_ASSOC_BUFSIZE];
935 struct device_node *cpu;
936 int nid = NUMA_NO_NODE;
937
938 memset(vphn_assoc, 0, VPHN_ASSOC_BUFSIZE * sizeof(__be32));
939
940 if (__vphn_get_associativity(lcpu: i, associativity: vphn_assoc) == 0) {
941 nid = associativity_to_nid(associativity: vphn_assoc);
942 initialize_form1_numa_distance(associativity: vphn_assoc);
943 } else {
944
945 /*
946 * Don't fall back to default_nid yet -- we will plug
947 * cpus into nodes once the memory scan has discovered
948 * the topology.
949 */
950 cpu = of_get_cpu_node(cpu: i, NULL);
951 BUG_ON(!cpu);
952
953 associativity = of_get_associativity(dev: cpu);
954 if (associativity) {
955 nid = associativity_to_nid(associativity);
956 initialize_form1_numa_distance(associativity);
957 }
958 of_node_put(node: cpu);
959 }
960
961 /* node_set_online() is an UB if 'nid' is negative */
962 if (likely(nid >= 0))
963 node_set_online(nid);
964 }
965
966 get_n_mem_cells(n_addr_cells: &n_mem_addr_cells, n_size_cells: &n_mem_size_cells);
967
968 for_each_node_by_type(memory, "memory") {
969 unsigned long start;
970 unsigned long size;
971 int nid;
972 int ranges;
973 const __be32 *memcell_buf;
974 unsigned int len;
975
976 memcell_buf = of_get_property(node: memory,
977 name: "linux,usable-memory", lenp: &len);
978 if (!memcell_buf || len <= 0)
979 memcell_buf = of_get_property(node: memory, name: "reg", lenp: &len);
980 if (!memcell_buf || len <= 0)
981 continue;
982
983 /* ranges in cell */
984 ranges = (len >> 2) / (n_mem_addr_cells + n_mem_size_cells);
985new_range:
986 /* these are order-sensitive, and modify the buffer pointer */
987 start = read_n_cells(n: n_mem_addr_cells, buf: &memcell_buf);
988 size = read_n_cells(n: n_mem_size_cells, buf: &memcell_buf);
989
990 /*
991 * Assumption: either all memory nodes or none will
992 * have associativity properties. If none, then
993 * everything goes to default_nid.
994 */
995 associativity = of_get_associativity(dev: memory);
996 if (associativity) {
997 nid = associativity_to_nid(associativity);
998 initialize_form1_numa_distance(associativity);
999 } else
1000 nid = default_nid;
1001
1002 fake_numa_create_new_node(end_pfn: ((start + size) >> PAGE_SHIFT), nid: &nid);
1003 node_set_online(nid);
1004
1005 size = numa_enforce_memory_limit(start, size);
1006 if (size)
1007 memblock_set_node(base: start, size, type: &memblock.memory, nid);
1008
1009 if (--ranges)
1010 goto new_range;
1011 }
1012
1013 /*
1014 * Now do the same thing for each MEMBLOCK listed in the
1015 * ibm,dynamic-memory property in the
1016 * ibm,dynamic-reconfiguration-memory node.
1017 */
1018 memory = of_find_node_by_path(path: "/ibm,dynamic-reconfiguration-memory");
1019 if (memory) {
1020 walk_drmem_lmbs(memory, NULL, numa_setup_drmem_lmb);
1021 of_node_put(node: memory);
1022 }
1023
1024 return 0;
1025}
1026
1027static void __init setup_nonnuma(void)
1028{
1029 unsigned long top_of_ram = memblock_end_of_DRAM();
1030 unsigned long total_ram = memblock_phys_mem_size();
1031 unsigned long start_pfn, end_pfn;
1032 unsigned int nid = 0;
1033 int i;
1034
1035 pr_debug("Top of RAM: 0x%lx, Total RAM: 0x%lx\n", top_of_ram, total_ram);
1036 pr_debug("Memory hole size: %ldMB\n", (top_of_ram - total_ram) >> 20);
1037
1038 for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, NULL) {
1039 fake_numa_create_new_node(end_pfn, nid: &nid);
1040 memblock_set_node(PFN_PHYS(start_pfn),
1041 PFN_PHYS(end_pfn - start_pfn),
1042 type: &memblock.memory, nid);
1043 node_set_online(nid);
1044 }
1045}
1046
1047void __init dump_numa_cpu_topology(void)
1048{
1049 unsigned int node;
1050 unsigned int cpu, count;
1051
1052 if (!numa_enabled)
1053 return;
1054
1055 for_each_online_node(node) {
1056 pr_info("Node %d CPUs:", node);
1057
1058 count = 0;
1059 /*
1060 * If we used a CPU iterator here we would miss printing
1061 * the holes in the cpumap.
1062 */
1063 for (cpu = 0; cpu < nr_cpu_ids; cpu++) {
1064 if (cpumask_test_cpu(cpu,
1065 cpumask: node_to_cpumask_map[node])) {
1066 if (count == 0)
1067 pr_cont(" %u", cpu);
1068 ++count;
1069 } else {
1070 if (count > 1)
1071 pr_cont("-%u", cpu - 1);
1072 count = 0;
1073 }
1074 }
1075
1076 if (count > 1)
1077 pr_cont("-%u", nr_cpu_ids - 1);
1078 pr_cont("\n");
1079 }
1080}
1081
1082/* Initialize NODE_DATA for a node on the local memory */
1083static void __init setup_node_data(int nid, u64 start_pfn, u64 end_pfn)
1084{
1085 u64 spanned_pages = end_pfn - start_pfn;
1086 const size_t nd_size = roundup(sizeof(pg_data_t), SMP_CACHE_BYTES);
1087 u64 nd_pa;
1088 void *nd;
1089 int tnid;
1090
1091 nd_pa = memblock_phys_alloc_try_nid(size: nd_size, SMP_CACHE_BYTES, nid);
1092 if (!nd_pa)
1093 panic(fmt: "Cannot allocate %zu bytes for node %d data\n",
1094 nd_size, nid);
1095
1096 nd = __va(nd_pa);
1097
1098 /* report and initialize */
1099 pr_info(" NODE_DATA [mem %#010Lx-%#010Lx]\n",
1100 nd_pa, nd_pa + nd_size - 1);
1101 tnid = early_pfn_to_nid(pfn: nd_pa >> PAGE_SHIFT);
1102 if (tnid != nid)
1103 pr_info(" NODE_DATA(%d) on node %d\n", nid, tnid);
1104
1105 node_data[nid] = nd;
1106 memset(NODE_DATA(nid), 0, sizeof(pg_data_t));
1107 NODE_DATA(nid)->node_id = nid;
1108 NODE_DATA(nid)->node_start_pfn = start_pfn;
1109 NODE_DATA(nid)->node_spanned_pages = spanned_pages;
1110}
1111
1112static void __init find_possible_nodes(void)
1113{
1114 struct device_node *rtas, *root;
1115 const __be32 *domains = NULL;
1116 int prop_length, max_nodes;
1117 u32 i;
1118
1119 if (!numa_enabled)
1120 return;
1121
1122 rtas = of_find_node_by_path(path: "/rtas");
1123 if (!rtas)
1124 return;
1125
1126 /*
1127 * ibm,current-associativity-domains is a fairly recent property. If
1128 * it doesn't exist, then fallback on ibm,max-associativity-domains.
1129 * Current denotes what the platform can support compared to max
1130 * which denotes what the Hypervisor can support.
1131 *
1132 * If the LPAR is migratable, new nodes might be activated after a LPM,
1133 * so we should consider the max number in that case.
1134 */
1135 root = of_find_node_by_path(path: "/");
1136 if (!of_get_property(node: root, name: "ibm,migratable-partition", NULL))
1137 domains = of_get_property(node: rtas,
1138 name: "ibm,current-associativity-domains",
1139 lenp: &prop_length);
1140 of_node_put(node: root);
1141 if (!domains) {
1142 domains = of_get_property(node: rtas, name: "ibm,max-associativity-domains",
1143 lenp: &prop_length);
1144 if (!domains)
1145 goto out;
1146 }
1147
1148 max_nodes = of_read_number(cell: &domains[primary_domain_index], size: 1);
1149 pr_info("Partition configured for %d NUMA nodes.\n", max_nodes);
1150
1151 for (i = 0; i < max_nodes; i++) {
1152 if (!node_possible(i))
1153 node_set(i, node_possible_map);
1154 }
1155
1156 prop_length /= sizeof(int);
1157 if (prop_length > primary_domain_index + 2)
1158 coregroup_enabled = 1;
1159
1160out:
1161 of_node_put(node: rtas);
1162}
1163
1164void __init mem_topology_setup(void)
1165{
1166 int cpu;
1167
1168 max_low_pfn = max_pfn = memblock_end_of_DRAM() >> PAGE_SHIFT;
1169 min_low_pfn = MEMORY_START >> PAGE_SHIFT;
1170
1171 /*
1172 * Linux/mm assumes node 0 to be online at boot. However this is not
1173 * true on PowerPC, where node 0 is similar to any other node, it
1174 * could be cpuless, memoryless node. So force node 0 to be offline
1175 * for now. This will prevent cpuless, memoryless node 0 showing up
1176 * unnecessarily as online. If a node has cpus or memory that need
1177 * to be online, then node will anyway be marked online.
1178 */
1179 node_set_offline(nid: 0);
1180
1181 if (parse_numa_properties())
1182 setup_nonnuma();
1183
1184 /*
1185 * Modify the set of possible NUMA nodes to reflect information
1186 * available about the set of online nodes, and the set of nodes
1187 * that we expect to make use of for this platform's affinity
1188 * calculations.
1189 */
1190 nodes_and(node_possible_map, node_possible_map, node_online_map);
1191
1192 find_possible_nodes();
1193
1194 setup_node_to_cpumask_map();
1195
1196 reset_numa_cpu_lookup_table();
1197
1198 for_each_possible_cpu(cpu) {
1199 /*
1200 * Powerpc with CONFIG_NUMA always used to have a node 0,
1201 * even if it was memoryless or cpuless. For all cpus that
1202 * are possible but not present, cpu_to_node() would point
1203 * to node 0. To remove a cpuless, memoryless dummy node,
1204 * powerpc need to make sure all possible but not present
1205 * cpu_to_node are set to a proper node.
1206 */
1207 numa_setup_cpu(lcpu: cpu);
1208 }
1209}
1210
1211void __init initmem_init(void)
1212{
1213 int nid;
1214
1215 memblock_dump_all();
1216
1217 for_each_online_node(nid) {
1218 unsigned long start_pfn, end_pfn;
1219
1220 get_pfn_range_for_nid(nid, start_pfn: &start_pfn, end_pfn: &end_pfn);
1221 setup_node_data(nid, start_pfn, end_pfn);
1222 }
1223
1224 sparse_init();
1225
1226 /*
1227 * We need the numa_cpu_lookup_table to be accurate for all CPUs,
1228 * even before we online them, so that we can use cpu_to_{node,mem}
1229 * early in boot, cf. smp_prepare_cpus().
1230 * _nocalls() + manual invocation is used because cpuhp is not yet
1231 * initialized for the boot CPU.
1232 */
1233 cpuhp_setup_state_nocalls(state: CPUHP_POWER_NUMA_PREPARE, name: "powerpc/numa:prepare",
1234 startup: ppc_numa_cpu_prepare, teardown: ppc_numa_cpu_dead);
1235}
1236
1237static int __init early_numa(char *p)
1238{
1239 if (!p)
1240 return 0;
1241
1242 if (strstr(p, "off"))
1243 numa_enabled = 0;
1244
1245 p = strstr(p, "fake=");
1246 if (p)
1247 cmdline = p + strlen("fake=");
1248
1249 return 0;
1250}
1251early_param("numa", early_numa);
1252
1253#ifdef CONFIG_MEMORY_HOTPLUG
1254/*
1255 * Find the node associated with a hot added memory section for
1256 * memory represented in the device tree by the property
1257 * ibm,dynamic-reconfiguration-memory/ibm,dynamic-memory.
1258 */
1259static int hot_add_drconf_scn_to_nid(unsigned long scn_addr)
1260{
1261 struct drmem_lmb *lmb;
1262 unsigned long lmb_size;
1263 int nid = NUMA_NO_NODE;
1264
1265 lmb_size = drmem_lmb_size();
1266
1267 for_each_drmem_lmb(lmb) {
1268 /* skip this block if it is reserved or not assigned to
1269 * this partition */
1270 if ((lmb->flags & DRCONF_MEM_RESERVED)
1271 || !(lmb->flags & DRCONF_MEM_ASSIGNED))
1272 continue;
1273
1274 if ((scn_addr < lmb->base_addr)
1275 || (scn_addr >= (lmb->base_addr + lmb_size)))
1276 continue;
1277
1278 nid = of_drconf_to_nid_single(lmb);
1279 break;
1280 }
1281
1282 return nid;
1283}
1284
1285/*
1286 * Find the node associated with a hot added memory section for memory
1287 * represented in the device tree as a node (i.e. memory@XXXX) for
1288 * each memblock.
1289 */
1290static int hot_add_node_scn_to_nid(unsigned long scn_addr)
1291{
1292 struct device_node *memory;
1293 int nid = NUMA_NO_NODE;
1294
1295 for_each_node_by_type(memory, "memory") {
1296 int i = 0;
1297
1298 while (1) {
1299 struct resource res;
1300
1301 if (of_address_to_resource(dev: memory, index: i++, r: &res))
1302 break;
1303
1304 if ((scn_addr < res.start) || (scn_addr > res.end))
1305 continue;
1306
1307 nid = of_node_to_nid_single(device: memory);
1308 break;
1309 }
1310
1311 if (nid >= 0)
1312 break;
1313 }
1314
1315 of_node_put(node: memory);
1316
1317 return nid;
1318}
1319
1320/*
1321 * Find the node associated with a hot added memory section. Section
1322 * corresponds to a SPARSEMEM section, not an MEMBLOCK. It is assumed that
1323 * sections are fully contained within a single MEMBLOCK.
1324 */
1325int hot_add_scn_to_nid(unsigned long scn_addr)
1326{
1327 struct device_node *memory = NULL;
1328 int nid;
1329
1330 if (!numa_enabled)
1331 return first_online_node;
1332
1333 memory = of_find_node_by_path(path: "/ibm,dynamic-reconfiguration-memory");
1334 if (memory) {
1335 nid = hot_add_drconf_scn_to_nid(scn_addr);
1336 of_node_put(node: memory);
1337 } else {
1338 nid = hot_add_node_scn_to_nid(scn_addr);
1339 }
1340
1341 if (nid < 0 || !node_possible(nid))
1342 nid = first_online_node;
1343
1344 return nid;
1345}
1346
1347static u64 hot_add_drconf_memory_max(void)
1348{
1349 struct device_node *memory = NULL;
1350 struct device_node *dn = NULL;
1351 const __be64 *lrdr = NULL;
1352
1353 dn = of_find_node_by_path(path: "/rtas");
1354 if (dn) {
1355 lrdr = of_get_property(node: dn, name: "ibm,lrdr-capacity", NULL);
1356 of_node_put(node: dn);
1357 if (lrdr)
1358 return be64_to_cpup(p: lrdr);
1359 }
1360
1361 memory = of_find_node_by_path(path: "/ibm,dynamic-reconfiguration-memory");
1362 if (memory) {
1363 of_node_put(node: memory);
1364 return drmem_lmb_memory_max();
1365 }
1366 return 0;
1367}
1368
1369/*
1370 * memory_hotplug_max - return max address of memory that may be added
1371 *
1372 * This is currently only used on systems that support drconfig memory
1373 * hotplug.
1374 */
1375u64 memory_hotplug_max(void)
1376{
1377 return max(hot_add_drconf_memory_max(), memblock_end_of_DRAM());
1378}
1379#endif /* CONFIG_MEMORY_HOTPLUG */
1380
1381/* Virtual Processor Home Node (VPHN) support */
1382#ifdef CONFIG_PPC_SPLPAR
1383static int topology_inited;
1384
1385/*
1386 * Retrieve the new associativity information for a virtual processor's
1387 * home node.
1388 */
1389static long vphn_get_associativity(unsigned long cpu,
1390 __be32 *associativity)
1391{
1392 long rc;
1393
1394 rc = hcall_vphn(get_hard_smp_processor_id(cpu),
1395 VPHN_FLAG_VCPU, associativity);
1396
1397 switch (rc) {
1398 case H_SUCCESS:
1399 pr_debug("VPHN hcall succeeded. Reset polling...\n");
1400 goto out;
1401
1402 case H_FUNCTION:
1403 pr_err_ratelimited("VPHN unsupported. Disabling polling...\n");
1404 break;
1405 case H_HARDWARE:
1406 pr_err_ratelimited("hcall_vphn() experienced a hardware fault "
1407 "preventing VPHN. Disabling polling...\n");
1408 break;
1409 case H_PARAMETER:
1410 pr_err_ratelimited("hcall_vphn() was passed an invalid parameter. "
1411 "Disabling polling...\n");
1412 break;
1413 default:
1414 pr_err_ratelimited("hcall_vphn() returned %ld. Disabling polling...\n"
1415 , rc);
1416 break;
1417 }
1418out:
1419 return rc;
1420}
1421
1422void find_and_update_cpu_nid(int cpu)
1423{
1424 __be32 associativity[VPHN_ASSOC_BUFSIZE] = {0};
1425 int new_nid;
1426
1427 /* Use associativity from first thread for all siblings */
1428 if (vphn_get_associativity(cpu, associativity))
1429 return;
1430
1431 /* Do not have previous associativity, so find it now. */
1432 new_nid = associativity_to_nid(associativity);
1433
1434 if (new_nid < 0 || !node_possible(new_nid))
1435 new_nid = first_online_node;
1436 else
1437 // Associate node <-> cpu, so cpu_up() calls
1438 // try_online_node() on the right node.
1439 set_cpu_numa_node(cpu, new_nid);
1440
1441 pr_debug("%s:%d cpu %d nid %d\n", __func__, __LINE__, cpu, new_nid);
1442}
1443
1444int cpu_to_coregroup_id(int cpu)
1445{
1446 __be32 associativity[VPHN_ASSOC_BUFSIZE] = {0};
1447 int index;
1448
1449 if (cpu < 0 || cpu > nr_cpu_ids)
1450 return -1;
1451
1452 if (!coregroup_enabled)
1453 goto out;
1454
1455 if (!firmware_has_feature(FW_FEATURE_VPHN))
1456 goto out;
1457
1458 if (vphn_get_associativity(cpu, associativity))
1459 goto out;
1460
1461 index = of_read_number(associativity, 1);
1462 if (index > primary_domain_index + 1)
1463 return of_read_number(&associativity[index - 1], 1);
1464
1465out:
1466 return cpu_to_core_id(cpu);
1467}
1468
1469static int topology_update_init(void)
1470{
1471 topology_inited = 1;
1472 return 0;
1473}
1474device_initcall(topology_update_init);
1475#endif /* CONFIG_PPC_SPLPAR */
1476

source code of linux/arch/powerpc/mm/numa.c