1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Basic Node interface support
4 */
5
6#include <linux/module.h>
7#include <linux/init.h>
8#include <linux/mm.h>
9#include <linux/memory.h>
10#include <linux/vmstat.h>
11#include <linux/notifier.h>
12#include <linux/node.h>
13#include <linux/hugetlb.h>
14#include <linux/compaction.h>
15#include <linux/cpumask.h>
16#include <linux/topology.h>
17#include <linux/nodemask.h>
18#include <linux/cpu.h>
19#include <linux/device.h>
20#include <linux/pm_runtime.h>
21#include <linux/swap.h>
22#include <linux/slab.h>
23
24static const struct bus_type node_subsys = {
25	.name = "node",
26	.dev_name = "node",
27};
28
29static inline ssize_t cpumap_read(struct file *file, struct kobject *kobj,
30				  struct bin_attribute *attr, char *buf,
31				  loff_t off, size_t count)
32{
33	struct device *dev = kobj_to_dev(kobj);
34	struct node *node_dev = to_node(dev);
35	cpumask_var_t mask;
36	ssize_t n;
37
38	if (!alloc_cpumask_var(&mask, GFP_KERNEL))
39		return 0;
40
41	cpumask_and(mask, cpumask_of_node(node_dev->dev.id), cpu_online_mask);
42	n = cpumap_print_bitmask_to_buf(buf, mask, off, count);
43	free_cpumask_var(mask);
44
45	return n;
46}
47
48static BIN_ATTR_RO(cpumap, CPUMAP_FILE_MAX_BYTES);
49
50static inline ssize_t cpulist_read(struct file *file, struct kobject *kobj,
51				   struct bin_attribute *attr, char *buf,
52				   loff_t off, size_t count)
53{
54	struct device *dev = kobj_to_dev(kobj);
55	struct node *node_dev = to_node(dev);
56	cpumask_var_t mask;
57	ssize_t n;
58
59	if (!alloc_cpumask_var(&mask, GFP_KERNEL))
60		return 0;
61
62	cpumask_and(mask, cpumask_of_node(node_dev->dev.id), cpu_online_mask);
63	n = cpumap_print_list_to_buf(buf, mask, off, count);
64	free_cpumask_var(mask);
65
66	return n;
67}
68
69static BIN_ATTR_RO(cpulist, CPULIST_FILE_MAX_BYTES);
70
71/**
72 * struct node_access_nodes - Access class device to hold user visible
73 * 			      relationships to other nodes.
74 * @dev:	Device for this memory access class
75 * @list_node:	List element in the node's access list
76 * @access:	The access class rank
77 * @coord:	Heterogeneous memory performance coordinates
78 */
79struct node_access_nodes {
80	struct device		dev;
81	struct list_head	list_node;
82	unsigned int		access;
83#ifdef CONFIG_HMEM_REPORTING
84	struct access_coordinate	coord;
85#endif
86};
87#define to_access_nodes(dev) container_of(dev, struct node_access_nodes, dev)
88
89static struct attribute *node_init_access_node_attrs[] = {
90	NULL,
91};
92
93static struct attribute *node_targ_access_node_attrs[] = {
94	NULL,
95};
96
97static const struct attribute_group initiators = {
98	.name	= "initiators",
99	.attrs	= node_init_access_node_attrs,
100};
101
102static const struct attribute_group targets = {
103	.name	= "targets",
104	.attrs	= node_targ_access_node_attrs,
105};
106
107static const struct attribute_group *node_access_node_groups[] = {
108	&initiators,
109	&targets,
110	NULL,
111};
112
113static void node_remove_accesses(struct node *node)
114{
115	struct node_access_nodes *c, *cnext;
116
117	list_for_each_entry_safe(c, cnext, &node->access_list, list_node) {
118		list_del(&c->list_node);
119		device_unregister(&c->dev);
120	}
121}
122
123static void node_access_release(struct device *dev)
124{
125	kfree(to_access_nodes(dev));
126}
127
128static struct node_access_nodes *node_init_node_access(struct node *node,
129						       enum access_coordinate_class access)
130{
131	struct node_access_nodes *access_node;
132	struct device *dev;
133
134	list_for_each_entry(access_node, &node->access_list, list_node)
135		if (access_node->access == access)
136			return access_node;
137
138	access_node = kzalloc(sizeof(*access_node), GFP_KERNEL);
139	if (!access_node)
140		return NULL;
141
142	access_node->access = access;
143	dev = &access_node->dev;
144	dev->parent = &node->dev;
145	dev->release = node_access_release;
146	dev->groups = node_access_node_groups;
147	if (dev_set_name(dev, "access%u", access))
148		goto free;
149
150	if (device_register(dev))
151		goto free_name;
152
153	pm_runtime_no_callbacks(dev);
154	list_add_tail(&access_node->list_node, &node->access_list);
155	return access_node;
156free_name:
157	kfree_const(dev->kobj.name);
158free:
159	kfree(access_node);
160	return NULL;
161}
162
163#ifdef CONFIG_HMEM_REPORTING
164#define ACCESS_ATTR(property)						\
165static ssize_t property##_show(struct device *dev,			\
166			   struct device_attribute *attr,		\
167			   char *buf)					\
168{									\
169	return sysfs_emit(buf, "%u\n",					\
170			  to_access_nodes(dev)->coord.property);	\
171}									\
172static DEVICE_ATTR_RO(property)
173
174ACCESS_ATTR(read_bandwidth);
175ACCESS_ATTR(read_latency);
176ACCESS_ATTR(write_bandwidth);
177ACCESS_ATTR(write_latency);
178
179static struct attribute *access_attrs[] = {
180	&dev_attr_read_bandwidth.attr,
181	&dev_attr_read_latency.attr,
182	&dev_attr_write_bandwidth.attr,
183	&dev_attr_write_latency.attr,
184	NULL,
185};
186
187/**
188 * node_set_perf_attrs - Set the performance values for given access class
189 * @nid: Node identifier to be set
190 * @coord: Heterogeneous memory performance coordinates
191 * @access: The access class the for the given attributes
192 */
193void node_set_perf_attrs(unsigned int nid, struct access_coordinate *coord,
194			 enum access_coordinate_class access)
195{
196	struct node_access_nodes *c;
197	struct node *node;
198	int i;
199
200	if (WARN_ON_ONCE(!node_online(nid)))
201		return;
202
203	node = node_devices[nid];
204	c = node_init_node_access(node, access);
205	if (!c)
206		return;
207
208	c->coord = *coord;
209	for (i = 0; access_attrs[i] != NULL; i++) {
210		if (sysfs_add_file_to_group(&c->dev.kobj, access_attrs[i],
211					    "initiators")) {
212			pr_info("failed to add performance attribute to node %d\n",
213				nid);
214			break;
215		}
216	}
217}
218EXPORT_SYMBOL_GPL(node_set_perf_attrs);
219
220/**
221 * struct node_cache_info - Internal tracking for memory node caches
222 * @dev:	Device represeting the cache level
223 * @node:	List element for tracking in the node
224 * @cache_attrs:Attributes for this cache level
225 */
226struct node_cache_info {
227	struct device dev;
228	struct list_head node;
229	struct node_cache_attrs cache_attrs;
230};
231#define to_cache_info(device) container_of(device, struct node_cache_info, dev)
232
233#define CACHE_ATTR(name, fmt) 						\
234static ssize_t name##_show(struct device *dev,				\
235			   struct device_attribute *attr,		\
236			   char *buf)					\
237{									\
238	return sysfs_emit(buf, fmt "\n",				\
239			  to_cache_info(dev)->cache_attrs.name);	\
240}									\
241static DEVICE_ATTR_RO(name);
242
243CACHE_ATTR(size, "%llu")
244CACHE_ATTR(line_size, "%u")
245CACHE_ATTR(indexing, "%u")
246CACHE_ATTR(write_policy, "%u")
247
248static struct attribute *cache_attrs[] = {
249	&dev_attr_indexing.attr,
250	&dev_attr_size.attr,
251	&dev_attr_line_size.attr,
252	&dev_attr_write_policy.attr,
253	NULL,
254};
255ATTRIBUTE_GROUPS(cache);
256
257static void node_cache_release(struct device *dev)
258{
259	kfree(dev);
260}
261
262static void node_cacheinfo_release(struct device *dev)
263{
264	struct node_cache_info *info = to_cache_info(dev);
265	kfree(info);
266}
267
268static void node_init_cache_dev(struct node *node)
269{
270	struct device *dev;
271
272	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
273	if (!dev)
274		return;
275
276	device_initialize(dev);
277	dev->parent = &node->dev;
278	dev->release = node_cache_release;
279	if (dev_set_name(dev, "memory_side_cache"))
280		goto put_device;
281
282	if (device_add(dev))
283		goto put_device;
284
285	pm_runtime_no_callbacks(dev);
286	node->cache_dev = dev;
287	return;
288put_device:
289	put_device(dev);
290}
291
292/**
293 * node_add_cache() - add cache attribute to a memory node
294 * @nid: Node identifier that has new cache attributes
295 * @cache_attrs: Attributes for the cache being added
296 */
297void node_add_cache(unsigned int nid, struct node_cache_attrs *cache_attrs)
298{
299	struct node_cache_info *info;
300	struct device *dev;
301	struct node *node;
302
303	if (!node_online(nid) || !node_devices[nid])
304		return;
305
306	node = node_devices[nid];
307	list_for_each_entry(info, &node->cache_attrs, node) {
308		if (info->cache_attrs.level == cache_attrs->level) {
309			dev_warn(&node->dev,
310				"attempt to add duplicate cache level:%d\n",
311				cache_attrs->level);
312			return;
313		}
314	}
315
316	if (!node->cache_dev)
317		node_init_cache_dev(node);
318	if (!node->cache_dev)
319		return;
320
321	info = kzalloc(sizeof(*info), GFP_KERNEL);
322	if (!info)
323		return;
324
325	dev = &info->dev;
326	device_initialize(dev);
327	dev->parent = node->cache_dev;
328	dev->release = node_cacheinfo_release;
329	dev->groups = cache_groups;
330	if (dev_set_name(dev, "index%d", cache_attrs->level))
331		goto put_device;
332
333	info->cache_attrs = *cache_attrs;
334	if (device_add(dev)) {
335		dev_warn(&node->dev, "failed to add cache level:%d\n",
336			 cache_attrs->level);
337		goto put_device;
338	}
339	pm_runtime_no_callbacks(dev);
340	list_add_tail(&info->node, &node->cache_attrs);
341	return;
342put_device:
343	put_device(dev);
344}
345
346static void node_remove_caches(struct node *node)
347{
348	struct node_cache_info *info, *next;
349
350	if (!node->cache_dev)
351		return;
352
353	list_for_each_entry_safe(info, next, &node->cache_attrs, node) {
354		list_del(&info->node);
355		device_unregister(&info->dev);
356	}
357	device_unregister(node->cache_dev);
358}
359
360static void node_init_caches(unsigned int nid)
361{
362	INIT_LIST_HEAD(&node_devices[nid]->cache_attrs);
363}
364#else
365static void node_init_caches(unsigned int nid) { }
366static void node_remove_caches(struct node *node) { }
367#endif
368
369#define K(x) ((x) << (PAGE_SHIFT - 10))
370static ssize_t node_read_meminfo(struct device *dev,
371			struct device_attribute *attr, char *buf)
372{
373	int len = 0;
374	int nid = dev->id;
375	struct pglist_data *pgdat = NODE_DATA(nid);
376	struct sysinfo i;
377	unsigned long sreclaimable, sunreclaimable;
378	unsigned long swapcached = 0;
379
380	si_meminfo_node(&i, nid);
381	sreclaimable = node_page_state_pages(pgdat, NR_SLAB_RECLAIMABLE_B);
382	sunreclaimable = node_page_state_pages(pgdat, NR_SLAB_UNRECLAIMABLE_B);
383#ifdef CONFIG_SWAP
384	swapcached = node_page_state_pages(pgdat, NR_SWAPCACHE);
385#endif
386	len = sysfs_emit_at(buf, len,
387			    "Node %d MemTotal:       %8lu kB\n"
388			    "Node %d MemFree:        %8lu kB\n"
389			    "Node %d MemUsed:        %8lu kB\n"
390			    "Node %d SwapCached:     %8lu kB\n"
391			    "Node %d Active:         %8lu kB\n"
392			    "Node %d Inactive:       %8lu kB\n"
393			    "Node %d Active(anon):   %8lu kB\n"
394			    "Node %d Inactive(anon): %8lu kB\n"
395			    "Node %d Active(file):   %8lu kB\n"
396			    "Node %d Inactive(file): %8lu kB\n"
397			    "Node %d Unevictable:    %8lu kB\n"
398			    "Node %d Mlocked:        %8lu kB\n",
399			    nid, K(i.totalram),
400			    nid, K(i.freeram),
401			    nid, K(i.totalram - i.freeram),
402			    nid, K(swapcached),
403			    nid, K(node_page_state(pgdat, NR_ACTIVE_ANON) +
404				   node_page_state(pgdat, NR_ACTIVE_FILE)),
405			    nid, K(node_page_state(pgdat, NR_INACTIVE_ANON) +
406				   node_page_state(pgdat, NR_INACTIVE_FILE)),
407			    nid, K(node_page_state(pgdat, NR_ACTIVE_ANON)),
408			    nid, K(node_page_state(pgdat, NR_INACTIVE_ANON)),
409			    nid, K(node_page_state(pgdat, NR_ACTIVE_FILE)),
410			    nid, K(node_page_state(pgdat, NR_INACTIVE_FILE)),
411			    nid, K(node_page_state(pgdat, NR_UNEVICTABLE)),
412			    nid, K(sum_zone_node_page_state(nid, NR_MLOCK)));
413
414#ifdef CONFIG_HIGHMEM
415	len += sysfs_emit_at(buf, len,
416			     "Node %d HighTotal:      %8lu kB\n"
417			     "Node %d HighFree:       %8lu kB\n"
418			     "Node %d LowTotal:       %8lu kB\n"
419			     "Node %d LowFree:        %8lu kB\n",
420			     nid, K(i.totalhigh),
421			     nid, K(i.freehigh),
422			     nid, K(i.totalram - i.totalhigh),
423			     nid, K(i.freeram - i.freehigh));
424#endif
425	len += sysfs_emit_at(buf, len,
426			     "Node %d Dirty:          %8lu kB\n"
427			     "Node %d Writeback:      %8lu kB\n"
428			     "Node %d FilePages:      %8lu kB\n"
429			     "Node %d Mapped:         %8lu kB\n"
430			     "Node %d AnonPages:      %8lu kB\n"
431			     "Node %d Shmem:          %8lu kB\n"
432			     "Node %d KernelStack:    %8lu kB\n"
433#ifdef CONFIG_SHADOW_CALL_STACK
434			     "Node %d ShadowCallStack:%8lu kB\n"
435#endif
436			     "Node %d PageTables:     %8lu kB\n"
437			     "Node %d SecPageTables:  %8lu kB\n"
438			     "Node %d NFS_Unstable:   %8lu kB\n"
439			     "Node %d Bounce:         %8lu kB\n"
440			     "Node %d WritebackTmp:   %8lu kB\n"
441			     "Node %d KReclaimable:   %8lu kB\n"
442			     "Node %d Slab:           %8lu kB\n"
443			     "Node %d SReclaimable:   %8lu kB\n"
444			     "Node %d SUnreclaim:     %8lu kB\n"
445#ifdef CONFIG_TRANSPARENT_HUGEPAGE
446			     "Node %d AnonHugePages:  %8lu kB\n"
447			     "Node %d ShmemHugePages: %8lu kB\n"
448			     "Node %d ShmemPmdMapped: %8lu kB\n"
449			     "Node %d FileHugePages:  %8lu kB\n"
450			     "Node %d FilePmdMapped:  %8lu kB\n"
451#endif
452#ifdef CONFIG_UNACCEPTED_MEMORY
453			     "Node %d Unaccepted:     %8lu kB\n"
454#endif
455			     ,
456			     nid, K(node_page_state(pgdat, NR_FILE_DIRTY)),
457			     nid, K(node_page_state(pgdat, NR_WRITEBACK)),
458			     nid, K(node_page_state(pgdat, NR_FILE_PAGES)),
459			     nid, K(node_page_state(pgdat, NR_FILE_MAPPED)),
460			     nid, K(node_page_state(pgdat, NR_ANON_MAPPED)),
461			     nid, K(i.sharedram),
462			     nid, node_page_state(pgdat, NR_KERNEL_STACK_KB),
463#ifdef CONFIG_SHADOW_CALL_STACK
464			     nid, node_page_state(pgdat, NR_KERNEL_SCS_KB),
465#endif
466			     nid, K(node_page_state(pgdat, NR_PAGETABLE)),
467			     nid, K(node_page_state(pgdat, NR_SECONDARY_PAGETABLE)),
468			     nid, 0UL,
469			     nid, K(sum_zone_node_page_state(nid, NR_BOUNCE)),
470			     nid, K(node_page_state(pgdat, NR_WRITEBACK_TEMP)),
471			     nid, K(sreclaimable +
472				    node_page_state(pgdat, NR_KERNEL_MISC_RECLAIMABLE)),
473			     nid, K(sreclaimable + sunreclaimable),
474			     nid, K(sreclaimable),
475			     nid, K(sunreclaimable)
476#ifdef CONFIG_TRANSPARENT_HUGEPAGE
477			     ,
478			     nid, K(node_page_state(pgdat, NR_ANON_THPS)),
479			     nid, K(node_page_state(pgdat, NR_SHMEM_THPS)),
480			     nid, K(node_page_state(pgdat, NR_SHMEM_PMDMAPPED)),
481			     nid, K(node_page_state(pgdat, NR_FILE_THPS)),
482			     nid, K(node_page_state(pgdat, NR_FILE_PMDMAPPED))
483#endif
484#ifdef CONFIG_UNACCEPTED_MEMORY
485			     ,
486			     nid, K(sum_zone_node_page_state(nid, NR_UNACCEPTED))
487#endif
488			    );
489	len += hugetlb_report_node_meminfo(buf, len, nid);
490	return len;
491}
492
493#undef K
494static DEVICE_ATTR(meminfo, 0444, node_read_meminfo, NULL);
495
496static ssize_t node_read_numastat(struct device *dev,
497				  struct device_attribute *attr, char *buf)
498{
499	fold_vm_numa_events();
500	return sysfs_emit(buf,
501			  "numa_hit %lu\n"
502			  "numa_miss %lu\n"
503			  "numa_foreign %lu\n"
504			  "interleave_hit %lu\n"
505			  "local_node %lu\n"
506			  "other_node %lu\n",
507			  sum_zone_numa_event_state(dev->id, NUMA_HIT),
508			  sum_zone_numa_event_state(dev->id, NUMA_MISS),
509			  sum_zone_numa_event_state(dev->id, NUMA_FOREIGN),
510			  sum_zone_numa_event_state(dev->id, NUMA_INTERLEAVE_HIT),
511			  sum_zone_numa_event_state(dev->id, NUMA_LOCAL),
512			  sum_zone_numa_event_state(dev->id, NUMA_OTHER));
513}
514static DEVICE_ATTR(numastat, 0444, node_read_numastat, NULL);
515
516static ssize_t node_read_vmstat(struct device *dev,
517				struct device_attribute *attr, char *buf)
518{
519	int nid = dev->id;
520	struct pglist_data *pgdat = NODE_DATA(nid);
521	int i;
522	int len = 0;
523
524	for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
525		len += sysfs_emit_at(buf, len, "%s %lu\n",
526				     zone_stat_name(i),
527				     sum_zone_node_page_state(nid, i));
528
529#ifdef CONFIG_NUMA
530	fold_vm_numa_events();
531	for (i = 0; i < NR_VM_NUMA_EVENT_ITEMS; i++)
532		len += sysfs_emit_at(buf, len, "%s %lu\n",
533				     numa_stat_name(i),
534				     sum_zone_numa_event_state(nid, i));
535
536#endif
537	for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
538		unsigned long pages = node_page_state_pages(pgdat, i);
539
540		if (vmstat_item_print_in_thp(i))
541			pages /= HPAGE_PMD_NR;
542		len += sysfs_emit_at(buf, len, "%s %lu\n", node_stat_name(i),
543				     pages);
544	}
545
546	return len;
547}
548static DEVICE_ATTR(vmstat, 0444, node_read_vmstat, NULL);
549
550static ssize_t node_read_distance(struct device *dev,
551				  struct device_attribute *attr, char *buf)
552{
553	int nid = dev->id;
554	int len = 0;
555	int i;
556
557	/*
558	 * buf is currently PAGE_SIZE in length and each node needs 4 chars
559	 * at the most (distance + space or newline).
560	 */
561	BUILD_BUG_ON(MAX_NUMNODES * 4 > PAGE_SIZE);
562
563	for_each_online_node(i) {
564		len += sysfs_emit_at(buf, len, "%s%d",
565				     i ? " " : "", node_distance(nid, i));
566	}
567
568	len += sysfs_emit_at(buf, len, "\n");
569	return len;
570}
571static DEVICE_ATTR(distance, 0444, node_read_distance, NULL);
572
573static struct attribute *node_dev_attrs[] = {
574	&dev_attr_meminfo.attr,
575	&dev_attr_numastat.attr,
576	&dev_attr_distance.attr,
577	&dev_attr_vmstat.attr,
578	NULL
579};
580
581static struct bin_attribute *node_dev_bin_attrs[] = {
582	&bin_attr_cpumap,
583	&bin_attr_cpulist,
584	NULL
585};
586
587static const struct attribute_group node_dev_group = {
588	.attrs = node_dev_attrs,
589	.bin_attrs = node_dev_bin_attrs
590};
591
592static const struct attribute_group *node_dev_groups[] = {
593	&node_dev_group,
594#ifdef CONFIG_HAVE_ARCH_NODE_DEV_GROUP
595	&arch_node_dev_group,
596#endif
597#ifdef CONFIG_MEMORY_FAILURE
598	&memory_failure_attr_group,
599#endif
600	NULL
601};
602
603static void node_device_release(struct device *dev)
604{
605	kfree(to_node(dev));
606}
607
608/*
609 * register_node - Setup a sysfs device for a node.
610 * @num - Node number to use when creating the device.
611 *
612 * Initialize and register the node device.
613 */
614static int register_node(struct node *node, int num)
615{
616	int error;
617
618	node->dev.id = num;
619	node->dev.bus = &node_subsys;
620	node->dev.release = node_device_release;
621	node->dev.groups = node_dev_groups;
622	error = device_register(&node->dev);
623
624	if (error) {
625		put_device(&node->dev);
626	} else {
627		hugetlb_register_node(node);
628		compaction_register_node(node);
629	}
630
631	return error;
632}
633
634/**
635 * unregister_node - unregister a node device
636 * @node: node going away
637 *
638 * Unregisters a node device @node.  All the devices on the node must be
639 * unregistered before calling this function.
640 */
641void unregister_node(struct node *node)
642{
643	hugetlb_unregister_node(node);
644	compaction_unregister_node(node);
645	node_remove_accesses(node);
646	node_remove_caches(node);
647	device_unregister(&node->dev);
648}
649
650struct node *node_devices[MAX_NUMNODES];
651
652/*
653 * register cpu under node
654 */
655int register_cpu_under_node(unsigned int cpu, unsigned int nid)
656{
657	int ret;
658	struct device *obj;
659
660	if (!node_online(nid))
661		return 0;
662
663	obj = get_cpu_device(cpu);
664	if (!obj)
665		return 0;
666
667	ret = sysfs_create_link(&node_devices[nid]->dev.kobj,
668				&obj->kobj,
669				kobject_name(&obj->kobj));
670	if (ret)
671		return ret;
672
673	return sysfs_create_link(&obj->kobj,
674				 &node_devices[nid]->dev.kobj,
675				 kobject_name(&node_devices[nid]->dev.kobj));
676}
677
678/**
679 * register_memory_node_under_compute_node - link memory node to its compute
680 *					     node for a given access class.
681 * @mem_nid:	Memory node number
682 * @cpu_nid:	Cpu  node number
683 * @access:	Access class to register
684 *
685 * Description:
686 * 	For use with platforms that may have separate memory and compute nodes.
687 * 	This function will export node relationships linking which memory
688 * 	initiator nodes can access memory targets at a given ranked access
689 * 	class.
690 */
691int register_memory_node_under_compute_node(unsigned int mem_nid,
692					    unsigned int cpu_nid,
693					    enum access_coordinate_class access)
694{
695	struct node *init_node, *targ_node;
696	struct node_access_nodes *initiator, *target;
697	int ret;
698
699	if (!node_online(cpu_nid) || !node_online(mem_nid))
700		return -ENODEV;
701
702	init_node = node_devices[cpu_nid];
703	targ_node = node_devices[mem_nid];
704	initiator = node_init_node_access(init_node, access);
705	target = node_init_node_access(targ_node, access);
706	if (!initiator || !target)
707		return -ENOMEM;
708
709	ret = sysfs_add_link_to_group(&initiator->dev.kobj, "targets",
710				      &targ_node->dev.kobj,
711				      dev_name(&targ_node->dev));
712	if (ret)
713		return ret;
714
715	ret = sysfs_add_link_to_group(&target->dev.kobj, "initiators",
716				      &init_node->dev.kobj,
717				      dev_name(&init_node->dev));
718	if (ret)
719		goto err;
720
721	return 0;
722 err:
723	sysfs_remove_link_from_group(&initiator->dev.kobj, "targets",
724				     dev_name(&targ_node->dev));
725	return ret;
726}
727
728int unregister_cpu_under_node(unsigned int cpu, unsigned int nid)
729{
730	struct device *obj;
731
732	if (!node_online(nid))
733		return 0;
734
735	obj = get_cpu_device(cpu);
736	if (!obj)
737		return 0;
738
739	sysfs_remove_link(&node_devices[nid]->dev.kobj,
740			  kobject_name(&obj->kobj));
741	sysfs_remove_link(&obj->kobj,
742			  kobject_name(&node_devices[nid]->dev.kobj));
743
744	return 0;
745}
746
747#ifdef CONFIG_MEMORY_HOTPLUG
748static int __ref get_nid_for_pfn(unsigned long pfn)
749{
750#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
751	if (system_state < SYSTEM_RUNNING)
752		return early_pfn_to_nid(pfn);
753#endif
754	return pfn_to_nid(pfn);
755}
756
757static void do_register_memory_block_under_node(int nid,
758						struct memory_block *mem_blk,
759						enum meminit_context context)
760{
761	int ret;
762
763	memory_block_add_nid(mem_blk, nid, context);
764
765	ret = sysfs_create_link_nowarn(&node_devices[nid]->dev.kobj,
766				       &mem_blk->dev.kobj,
767				       kobject_name(&mem_blk->dev.kobj));
768	if (ret && ret != -EEXIST)
769		dev_err_ratelimited(&node_devices[nid]->dev,
770				    "can't create link to %s in sysfs (%d)\n",
771				    kobject_name(&mem_blk->dev.kobj), ret);
772
773	ret = sysfs_create_link_nowarn(&mem_blk->dev.kobj,
774				&node_devices[nid]->dev.kobj,
775				kobject_name(&node_devices[nid]->dev.kobj));
776	if (ret && ret != -EEXIST)
777		dev_err_ratelimited(&mem_blk->dev,
778				    "can't create link to %s in sysfs (%d)\n",
779				    kobject_name(&node_devices[nid]->dev.kobj),
780				    ret);
781}
782
783/* register memory section under specified node if it spans that node */
784static int register_mem_block_under_node_early(struct memory_block *mem_blk,
785					       void *arg)
786{
787	unsigned long memory_block_pfns = memory_block_size_bytes() / PAGE_SIZE;
788	unsigned long start_pfn = section_nr_to_pfn(mem_blk->start_section_nr);
789	unsigned long end_pfn = start_pfn + memory_block_pfns - 1;
790	int nid = *(int *)arg;
791	unsigned long pfn;
792
793	for (pfn = start_pfn; pfn <= end_pfn; pfn++) {
794		int page_nid;
795
796		/*
797		 * memory block could have several absent sections from start.
798		 * skip pfn range from absent section
799		 */
800		if (!pfn_in_present_section(pfn)) {
801			pfn = round_down(pfn + PAGES_PER_SECTION,
802					 PAGES_PER_SECTION) - 1;
803			continue;
804		}
805
806		/*
807		 * We need to check if page belongs to nid only at the boot
808		 * case because node's ranges can be interleaved.
809		 */
810		page_nid = get_nid_for_pfn(pfn);
811		if (page_nid < 0)
812			continue;
813		if (page_nid != nid)
814			continue;
815
816		do_register_memory_block_under_node(nid, mem_blk, MEMINIT_EARLY);
817		return 0;
818	}
819	/* mem section does not span the specified node */
820	return 0;
821}
822
823/*
824 * During hotplug we know that all pages in the memory block belong to the same
825 * node.
826 */
827static int register_mem_block_under_node_hotplug(struct memory_block *mem_blk,
828						 void *arg)
829{
830	int nid = *(int *)arg;
831
832	do_register_memory_block_under_node(nid, mem_blk, MEMINIT_HOTPLUG);
833	return 0;
834}
835
836/*
837 * Unregister a memory block device under the node it spans. Memory blocks
838 * with multiple nodes cannot be offlined and therefore also never be removed.
839 */
840void unregister_memory_block_under_nodes(struct memory_block *mem_blk)
841{
842	if (mem_blk->nid == NUMA_NO_NODE)
843		return;
844
845	sysfs_remove_link(&node_devices[mem_blk->nid]->dev.kobj,
846			  kobject_name(&mem_blk->dev.kobj));
847	sysfs_remove_link(&mem_blk->dev.kobj,
848			  kobject_name(&node_devices[mem_blk->nid]->dev.kobj));
849}
850
851void register_memory_blocks_under_node(int nid, unsigned long start_pfn,
852				       unsigned long end_pfn,
853				       enum meminit_context context)
854{
855	walk_memory_blocks_func_t func;
856
857	if (context == MEMINIT_HOTPLUG)
858		func = register_mem_block_under_node_hotplug;
859	else
860		func = register_mem_block_under_node_early;
861
862	walk_memory_blocks(PFN_PHYS(start_pfn), PFN_PHYS(end_pfn - start_pfn),
863			   (void *)&nid, func);
864	return;
865}
866#endif /* CONFIG_MEMORY_HOTPLUG */
867
868int __register_one_node(int nid)
869{
870	int error;
871	int cpu;
872	struct node *node;
873
874	node = kzalloc(sizeof(struct node), GFP_KERNEL);
875	if (!node)
876		return -ENOMEM;
877
878	INIT_LIST_HEAD(&node->access_list);
879	node_devices[nid] = node;
880
881	error = register_node(node_devices[nid], nid);
882
883	/* link cpu under this node */
884	for_each_present_cpu(cpu) {
885		if (cpu_to_node(cpu) == nid)
886			register_cpu_under_node(cpu, nid);
887	}
888
889	node_init_caches(nid);
890
891	return error;
892}
893
894void unregister_one_node(int nid)
895{
896	if (!node_devices[nid])
897		return;
898
899	unregister_node(node_devices[nid]);
900	node_devices[nid] = NULL;
901}
902
903/*
904 * node states attributes
905 */
906
907struct node_attr {
908	struct device_attribute attr;
909	enum node_states state;
910};
911
912static ssize_t show_node_state(struct device *dev,
913			       struct device_attribute *attr, char *buf)
914{
915	struct node_attr *na = container_of(attr, struct node_attr, attr);
916
917	return sysfs_emit(buf, "%*pbl\n",
918			  nodemask_pr_args(&node_states[na->state]));
919}
920
921#define _NODE_ATTR(name, state) \
922	{ __ATTR(name, 0444, show_node_state, NULL), state }
923
924static struct node_attr node_state_attr[] = {
925	[N_POSSIBLE] = _NODE_ATTR(possible, N_POSSIBLE),
926	[N_ONLINE] = _NODE_ATTR(online, N_ONLINE),
927	[N_NORMAL_MEMORY] = _NODE_ATTR(has_normal_memory, N_NORMAL_MEMORY),
928#ifdef CONFIG_HIGHMEM
929	[N_HIGH_MEMORY] = _NODE_ATTR(has_high_memory, N_HIGH_MEMORY),
930#endif
931	[N_MEMORY] = _NODE_ATTR(has_memory, N_MEMORY),
932	[N_CPU] = _NODE_ATTR(has_cpu, N_CPU),
933	[N_GENERIC_INITIATOR] = _NODE_ATTR(has_generic_initiator,
934					   N_GENERIC_INITIATOR),
935};
936
937static struct attribute *node_state_attrs[] = {
938	&node_state_attr[N_POSSIBLE].attr.attr,
939	&node_state_attr[N_ONLINE].attr.attr,
940	&node_state_attr[N_NORMAL_MEMORY].attr.attr,
941#ifdef CONFIG_HIGHMEM
942	&node_state_attr[N_HIGH_MEMORY].attr.attr,
943#endif
944	&node_state_attr[N_MEMORY].attr.attr,
945	&node_state_attr[N_CPU].attr.attr,
946	&node_state_attr[N_GENERIC_INITIATOR].attr.attr,
947	NULL
948};
949
950static const struct attribute_group memory_root_attr_group = {
951	.attrs = node_state_attrs,
952};
953
954static const struct attribute_group *cpu_root_attr_groups[] = {
955	&memory_root_attr_group,
956	NULL,
957};
958
959void __init node_dev_init(void)
960{
961	int ret, i;
962
963 	BUILD_BUG_ON(ARRAY_SIZE(node_state_attr) != NR_NODE_STATES);
964 	BUILD_BUG_ON(ARRAY_SIZE(node_state_attrs)-1 != NR_NODE_STATES);
965
966	ret = subsys_system_register(&node_subsys, cpu_root_attr_groups);
967	if (ret)
968		panic("%s() failed to register subsystem: %d\n", __func__, ret);
969
970	/*
971	 * Create all node devices, which will properly link the node
972	 * to applicable memory block devices and already created cpu devices.
973	 */
974	for_each_online_node(i) {
975		ret = register_one_node(i);
976		if (ret)
977			panic("%s() failed to add node: %d\n", __func__, ret);
978	}
979}
980