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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Memory subsystem support
4 *
5 * Written by Matt Tolentino <matthew.e.tolentino@intel.com>
6 * Dave Hansen <haveblue@us.ibm.com>
7 *
8 * This file provides the necessary infrastructure to represent
9 * a SPARSEMEM-memory-model system's physical memory in /sysfs.
10 * All arch-independent code that assumes MEMORY_HOTPLUG requires
11 * SPARSEMEM should be contained here, or in mm/memory_hotplug.c.
12 */
13
14#include <linux/module.h>
15#include <linux/init.h>
16#include <linux/topology.h>
17#include <linux/capability.h>
18#include <linux/device.h>
19#include <linux/memory.h>
20#include <linux/memory_hotplug.h>
21#include <linux/mm.h>
22#include <linux/stat.h>
23#include <linux/slab.h>
24#include <linux/xarray.h>
25
26#include <linux/atomic.h>
27#include <linux/uaccess.h>
28
29#define MEMORY_CLASS_NAME "memory"
30
31static const char *const online_type_to_str[] = {
32 [MMOP_OFFLINE] = "offline",
33 [MMOP_ONLINE] = "online",
34 [MMOP_ONLINE_KERNEL] = "online_kernel",
35 [MMOP_ONLINE_MOVABLE] = "online_movable",
36};
37
38int mhp_online_type_from_str(const char *str)
39{
40 int i;
41
42 for (i = 0; i < ARRAY_SIZE(online_type_to_str); i++) {
43 if (sysfs_streq(str, online_type_to_str[i]))
44 return i;
45 }
46 return -EINVAL;
47}
48
49#define to_memory_block(dev) container_of(dev, struct memory_block, dev)
50
51static int sections_per_block;
52
53static inline unsigned long memory_block_id(unsigned long section_nr)
54{
55 return section_nr / sections_per_block;
56}
57
58static inline unsigned long pfn_to_block_id(unsigned long pfn)
59{
60 return memory_block_id(pfn_to_section_nr(pfn));
61}
62
63static inline unsigned long phys_to_block_id(unsigned long phys)
64{
65 return pfn_to_block_id(PFN_DOWN(phys));
66}
67
68static int memory_subsys_online(struct device *dev);
69static int memory_subsys_offline(struct device *dev);
70
71static struct bus_type memory_subsys = {
72 .name = MEMORY_CLASS_NAME,
73 .dev_name = MEMORY_CLASS_NAME,
74 .online = memory_subsys_online,
75 .offline = memory_subsys_offline,
76};
77
78/*
79 * Memory blocks are cached in a local radix tree to avoid
80 * a costly linear search for the corresponding device on
81 * the subsystem bus.
82 */
83static DEFINE_XARRAY(memory_blocks);
84
85/*
86 * Memory groups, indexed by memory group id (mgid).
87 */
88static DEFINE_XARRAY_FLAGS(memory_groups, XA_FLAGS_ALLOC);
89#define MEMORY_GROUP_MARK_DYNAMIC XA_MARK_1
90
91static BLOCKING_NOTIFIER_HEAD(memory_chain);
92
93int register_memory_notifier(struct notifier_block *nb)
94{
95 return blocking_notifier_chain_register(&memory_chain, nb);
96}
97EXPORT_SYMBOL(register_memory_notifier);
98
99void unregister_memory_notifier(struct notifier_block *nb)
100{
101 blocking_notifier_chain_unregister(&memory_chain, nb);
102}
103EXPORT_SYMBOL(unregister_memory_notifier);
104
105static void memory_block_release(struct device *dev)
106{
107 struct memory_block *mem = to_memory_block(dev);
108
109 kfree(mem);
110}
111
112unsigned long __weak memory_block_size_bytes(void)
113{
114 return MIN_MEMORY_BLOCK_SIZE;
115}
116EXPORT_SYMBOL_GPL(memory_block_size_bytes);
117
118/*
119 * Show the first physical section index (number) of this memory block.
120 */
121static ssize_t phys_index_show(struct device *dev,
122 struct device_attribute *attr, char *buf)
123{
124 struct memory_block *mem = to_memory_block(dev);
125 unsigned long phys_index;
126
127 phys_index = mem->start_section_nr / sections_per_block;
128
129 return sysfs_emit(buf, "%08lx\n", phys_index);
130}
131
132/*
133 * Legacy interface that we cannot remove. Always indicate "removable"
134 * with CONFIG_MEMORY_HOTREMOVE - bad heuristic.
135 */
136static ssize_t removable_show(struct device *dev, struct device_attribute *attr,
137 char *buf)
138{
139 return sysfs_emit(buf, "%d\n", (int)IS_ENABLED(CONFIG_MEMORY_HOTREMOVE));
140}
141
142/*
143 * online, offline, going offline, etc.
144 */
145static ssize_t state_show(struct device *dev, struct device_attribute *attr,
146 char *buf)
147{
148 struct memory_block *mem = to_memory_block(dev);
149 const char *output;
150
151 /*
152 * We can probably put these states in a nice little array
153 * so that they're not open-coded
154 */
155 switch (mem->state) {
156 case MEM_ONLINE:
157 output = "online";
158 break;
159 case MEM_OFFLINE:
160 output = "offline";
161 break;
162 case MEM_GOING_OFFLINE:
163 output = "going-offline";
164 break;
165 default:
166 WARN_ON(1);
167 return sysfs_emit(buf, "ERROR-UNKNOWN-%ld\n", mem->state);
168 }
169
170 return sysfs_emit(buf, "%s\n", output);
171}
172
173int memory_notify(unsigned long val, void *v)
174{
175 return blocking_notifier_call_chain(&memory_chain, val, v);
176}
177
178#if defined(CONFIG_MEMORY_FAILURE) && defined(CONFIG_MEMORY_HOTPLUG)
179static unsigned long memblk_nr_poison(struct memory_block *mem);
180#else
181static inline unsigned long memblk_nr_poison(struct memory_block *mem)
182{
183 return 0;
184}
185#endif
186
187static int memory_block_online(struct memory_block *mem)
188{
189 unsigned long start_pfn = section_nr_to_pfn(mem->start_section_nr);
190 unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block;
191 unsigned long nr_vmemmap_pages = mem->nr_vmemmap_pages;
192 struct zone *zone;
193 int ret;
194
195 if (memblk_nr_poison(mem))
196 return -EHWPOISON;
197
198 zone = zone_for_pfn_range(mem->online_type, mem->nid, mem->group,
199 start_pfn, nr_pages);
200
201 /*
202 * Although vmemmap pages have a different lifecycle than the pages
203 * they describe (they remain until the memory is unplugged), doing
204 * their initialization and accounting at memory onlining/offlining
205 * stage helps to keep accounting easier to follow - e.g vmemmaps
206 * belong to the same zone as the memory they backed.
207 */
208 if (nr_vmemmap_pages) {
209 ret = mhp_init_memmap_on_memory(start_pfn, nr_vmemmap_pages, zone);
210 if (ret)
211 return ret;
212 }
213
214 ret = online_pages(start_pfn + nr_vmemmap_pages,
215 nr_pages - nr_vmemmap_pages, zone, mem->group);
216 if (ret) {
217 if (nr_vmemmap_pages)
218 mhp_deinit_memmap_on_memory(start_pfn, nr_vmemmap_pages);
219 return ret;
220 }
221
222 /*
223 * Account once onlining succeeded. If the zone was unpopulated, it is
224 * now already properly populated.
225 */
226 if (nr_vmemmap_pages)
227 adjust_present_page_count(pfn_to_page(start_pfn), mem->group,
228 nr_vmemmap_pages);
229
230 mem->zone = zone;
231 return ret;
232}
233
234static int memory_block_offline(struct memory_block *mem)
235{
236 unsigned long start_pfn = section_nr_to_pfn(mem->start_section_nr);
237 unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block;
238 unsigned long nr_vmemmap_pages = mem->nr_vmemmap_pages;
239 int ret;
240
241 if (!mem->zone)
242 return -EINVAL;
243
244 /*
245 * Unaccount before offlining, such that unpopulated zone and kthreads
246 * can properly be torn down in offline_pages().
247 */
248 if (nr_vmemmap_pages)
249 adjust_present_page_count(pfn_to_page(start_pfn), mem->group,
250 -nr_vmemmap_pages);
251
252 ret = offline_pages(start_pfn + nr_vmemmap_pages,
253 nr_pages - nr_vmemmap_pages, mem->zone, mem->group);
254 if (ret) {
255 /* offline_pages() failed. Account back. */
256 if (nr_vmemmap_pages)
257 adjust_present_page_count(pfn_to_page(start_pfn),
258 mem->group, nr_vmemmap_pages);
259 return ret;
260 }
261
262 if (nr_vmemmap_pages)
263 mhp_deinit_memmap_on_memory(start_pfn, nr_vmemmap_pages);
264
265 mem->zone = NULL;
266 return ret;
267}
268
269/*
270 * MEMORY_HOTPLUG depends on SPARSEMEM in mm/Kconfig, so it is
271 * OK to have direct references to sparsemem variables in here.
272 */
273static int
274memory_block_action(struct memory_block *mem, unsigned long action)
275{
276 int ret;
277
278 switch (action) {
279 case MEM_ONLINE:
280 ret = memory_block_online(mem);
281 break;
282 case MEM_OFFLINE:
283 ret = memory_block_offline(mem);
284 break;
285 default:
286 WARN(1, KERN_WARNING "%s(%ld, %ld) unknown action: "
287 "%ld\n", __func__, mem->start_section_nr, action, action);
288 ret = -EINVAL;
289 }
290
291 return ret;
292}
293
294static int memory_block_change_state(struct memory_block *mem,
295 unsigned long to_state, unsigned long from_state_req)
296{
297 int ret = 0;
298
299 if (mem->state != from_state_req)
300 return -EINVAL;
301
302 if (to_state == MEM_OFFLINE)
303 mem->state = MEM_GOING_OFFLINE;
304
305 ret = memory_block_action(mem, to_state);
306 mem->state = ret ? from_state_req : to_state;
307
308 return ret;
309}
310
311/* The device lock serializes operations on memory_subsys_[online|offline] */
312static int memory_subsys_online(struct device *dev)
313{
314 struct memory_block *mem = to_memory_block(dev);
315 int ret;
316
317 if (mem->state == MEM_ONLINE)
318 return 0;
319
320 /*
321 * When called via device_online() without configuring the online_type,
322 * we want to default to MMOP_ONLINE.
323 */
324 if (mem->online_type == MMOP_OFFLINE)
325 mem->online_type = MMOP_ONLINE;
326
327 ret = memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE);
328 mem->online_type = MMOP_OFFLINE;
329
330 return ret;
331}
332
333static int memory_subsys_offline(struct device *dev)
334{
335 struct memory_block *mem = to_memory_block(dev);
336
337 if (mem->state == MEM_OFFLINE)
338 return 0;
339
340 return memory_block_change_state(mem, MEM_OFFLINE, MEM_ONLINE);
341}
342
343static ssize_t state_store(struct device *dev, struct device_attribute *attr,
344 const char *buf, size_t count)
345{
346 const int online_type = mhp_online_type_from_str(buf);
347 struct memory_block *mem = to_memory_block(dev);
348 int ret;
349
350 if (online_type < 0)
351 return -EINVAL;
352
353 ret = lock_device_hotplug_sysfs();
354 if (ret)
355 return ret;
356
357 switch (online_type) {
358 case MMOP_ONLINE_KERNEL:
359 case MMOP_ONLINE_MOVABLE:
360 case MMOP_ONLINE:
361 /* mem->online_type is protected by device_hotplug_lock */
362 mem->online_type = online_type;
363 ret = device_online(&mem->dev);
364 break;
365 case MMOP_OFFLINE:
366 ret = device_offline(&mem->dev);
367 break;
368 default:
369 ret = -EINVAL; /* should never happen */
370 }
371
372 unlock_device_hotplug();
373
374 if (ret < 0)
375 return ret;
376 if (ret)
377 return -EINVAL;
378
379 return count;
380}
381
382/*
383 * Legacy interface that we cannot remove: s390x exposes the storage increment
384 * covered by a memory block, allowing for identifying which memory blocks
385 * comprise a storage increment. Since a memory block spans complete
386 * storage increments nowadays, this interface is basically unused. Other
387 * archs never exposed != 0.
388 */
389static ssize_t phys_device_show(struct device *dev,
390 struct device_attribute *attr, char *buf)
391{
392 struct memory_block *mem = to_memory_block(dev);
393 unsigned long start_pfn = section_nr_to_pfn(mem->start_section_nr);
394
395 return sysfs_emit(buf, "%d\n",
396 arch_get_memory_phys_device(start_pfn));
397}
398
399#ifdef CONFIG_MEMORY_HOTREMOVE
400static int print_allowed_zone(char *buf, int len, int nid,
401 struct memory_group *group,
402 unsigned long start_pfn, unsigned long nr_pages,
403 int online_type, struct zone *default_zone)
404{
405 struct zone *zone;
406
407 zone = zone_for_pfn_range(online_type, nid, group, start_pfn, nr_pages);
408 if (zone == default_zone)
409 return 0;
410
411 return sysfs_emit_at(buf, len, " %s", zone->name);
412}
413
414static ssize_t valid_zones_show(struct device *dev,
415 struct device_attribute *attr, char *buf)
416{
417 struct memory_block *mem = to_memory_block(dev);
418 unsigned long start_pfn = section_nr_to_pfn(mem->start_section_nr);
419 unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block;
420 struct memory_group *group = mem->group;
421 struct zone *default_zone;
422 int nid = mem->nid;
423 int len = 0;
424
425 /*
426 * Check the existing zone. Make sure that we do that only on the
427 * online nodes otherwise the page_zone is not reliable
428 */
429 if (mem->state == MEM_ONLINE) {
430 /*
431 * If !mem->zone, the memory block spans multiple zones and
432 * cannot get offlined.
433 */
434 default_zone = mem->zone;
435 if (!default_zone)
436 return sysfs_emit(buf, "%s\n", "none");
437 len += sysfs_emit_at(buf, len, "%s", default_zone->name);
438 goto out;
439 }
440
441 default_zone = zone_for_pfn_range(MMOP_ONLINE, nid, group,
442 start_pfn, nr_pages);
443
444 len += sysfs_emit_at(buf, len, "%s", default_zone->name);
445 len += print_allowed_zone(buf, len, nid, group, start_pfn, nr_pages,
446 MMOP_ONLINE_KERNEL, default_zone);
447 len += print_allowed_zone(buf, len, nid, group, start_pfn, nr_pages,
448 MMOP_ONLINE_MOVABLE, default_zone);
449out:
450 len += sysfs_emit_at(buf, len, "\n");
451 return len;
452}
453static DEVICE_ATTR_RO(valid_zones);
454#endif
455
456static DEVICE_ATTR_RO(phys_index);
457static DEVICE_ATTR_RW(state);
458static DEVICE_ATTR_RO(phys_device);
459static DEVICE_ATTR_RO(removable);
460
461/*
462 * Show the memory block size (shared by all memory blocks).
463 */
464static ssize_t block_size_bytes_show(struct device *dev,
465 struct device_attribute *attr, char *buf)
466{
467 return sysfs_emit(buf, "%lx\n", memory_block_size_bytes());
468}
469
470static DEVICE_ATTR_RO(block_size_bytes);
471
472/*
473 * Memory auto online policy.
474 */
475
476static ssize_t auto_online_blocks_show(struct device *dev,
477 struct device_attribute *attr, char *buf)
478{
479 return sysfs_emit(buf, "%s\n",
480 online_type_to_str[mhp_default_online_type]);
481}
482
483static ssize_t auto_online_blocks_store(struct device *dev,
484 struct device_attribute *attr,
485 const char *buf, size_t count)
486{
487 const int online_type = mhp_online_type_from_str(buf);
488
489 if (online_type < 0)
490 return -EINVAL;
491
492 mhp_default_online_type = online_type;
493 return count;
494}
495
496static DEVICE_ATTR_RW(auto_online_blocks);
497
498/*
499 * Some architectures will have custom drivers to do this, and
500 * will not need to do it from userspace. The fake hot-add code
501 * as well as ppc64 will do all of their discovery in userspace
502 * and will require this interface.
503 */
504#ifdef CONFIG_ARCH_MEMORY_PROBE
505static ssize_t probe_store(struct device *dev, struct device_attribute *attr,
506 const char *buf, size_t count)
507{
508 u64 phys_addr;
509 int nid, ret;
510 unsigned long pages_per_block = PAGES_PER_SECTION * sections_per_block;
511
512 ret = kstrtoull(buf, 0, &phys_addr);
513 if (ret)
514 return ret;
515
516 if (phys_addr & ((pages_per_block << PAGE_SHIFT) - 1))
517 return -EINVAL;
518
519 ret = lock_device_hotplug_sysfs();
520 if (ret)
521 return ret;
522
523 nid = memory_add_physaddr_to_nid(phys_addr);
524 ret = __add_memory(nid, phys_addr,
525 MIN_MEMORY_BLOCK_SIZE * sections_per_block,
526 MHP_NONE);
527
528 if (ret)
529 goto out;
530
531 ret = count;
532out:
533 unlock_device_hotplug();
534 return ret;
535}
536
537static DEVICE_ATTR_WO(probe);
538#endif
539
540#ifdef CONFIG_MEMORY_FAILURE
541/*
542 * Support for offlining pages of memory
543 */
544
545/* Soft offline a page */
546static ssize_t soft_offline_page_store(struct device *dev,
547 struct device_attribute *attr,
548 const char *buf, size_t count)
549{
550 int ret;
551 u64 pfn;
552 if (!capable(CAP_SYS_ADMIN))
553 return -EPERM;
554 if (kstrtoull(buf, 0, &pfn) < 0)
555 return -EINVAL;
556 pfn >>= PAGE_SHIFT;
557 ret = soft_offline_page(pfn, 0);
558 return ret == 0 ? count : ret;
559}
560
561/* Forcibly offline a page, including killing processes. */
562static ssize_t hard_offline_page_store(struct device *dev,
563 struct device_attribute *attr,
564 const char *buf, size_t count)
565{
566 int ret;
567 u64 pfn;
568 if (!capable(CAP_SYS_ADMIN))
569 return -EPERM;
570 if (kstrtoull(buf, 0, &pfn) < 0)
571 return -EINVAL;
572 pfn >>= PAGE_SHIFT;
573 ret = memory_failure(pfn, MF_SW_SIMULATED);
574 if (ret == -EOPNOTSUPP)
575 ret = 0;
576 return ret ? ret : count;
577}
578
579static DEVICE_ATTR_WO(soft_offline_page);
580static DEVICE_ATTR_WO(hard_offline_page);
581#endif
582
583/* See phys_device_show(). */
584int __weak arch_get_memory_phys_device(unsigned long start_pfn)
585{
586 return 0;
587}
588
589/*
590 * A reference for the returned memory block device is acquired.
591 *
592 * Called under device_hotplug_lock.
593 */
594static struct memory_block *find_memory_block_by_id(unsigned long block_id)
595{
596 struct memory_block *mem;
597
598 mem = xa_load(&memory_blocks, block_id);
599 if (mem)
600 get_device(&mem->dev);
601 return mem;
602}
603
604/*
605 * Called under device_hotplug_lock.
606 */
607struct memory_block *find_memory_block(unsigned long section_nr)
608{
609 unsigned long block_id = memory_block_id(section_nr);
610
611 return find_memory_block_by_id(block_id);
612}
613
614static struct attribute *memory_memblk_attrs[] = {
615 &dev_attr_phys_index.attr,
616 &dev_attr_state.attr,
617 &dev_attr_phys_device.attr,
618 &dev_attr_removable.attr,
619#ifdef CONFIG_MEMORY_HOTREMOVE
620 &dev_attr_valid_zones.attr,
621#endif
622 NULL
623};
624
625static const struct attribute_group memory_memblk_attr_group = {
626 .attrs = memory_memblk_attrs,
627};
628
629static const struct attribute_group *memory_memblk_attr_groups[] = {
630 &memory_memblk_attr_group,
631 NULL,
632};
633
634static int __add_memory_block(struct memory_block *memory)
635{
636 int ret;
637
638 memory->dev.bus = &memory_subsys;
639 memory->dev.id = memory->start_section_nr / sections_per_block;
640 memory->dev.release = memory_block_release;
641 memory->dev.groups = memory_memblk_attr_groups;
642 memory->dev.offline = memory->state == MEM_OFFLINE;
643
644 ret = device_register(&memory->dev);
645 if (ret) {
646 put_device(&memory->dev);
647 return ret;
648 }
649 ret = xa_err(xa_store(&memory_blocks, memory->dev.id, memory,
650 GFP_KERNEL));
651 if (ret)
652 device_unregister(&memory->dev);
653
654 return ret;
655}
656
657static struct zone *early_node_zone_for_memory_block(struct memory_block *mem,
658 int nid)
659{
660 const unsigned long start_pfn = section_nr_to_pfn(mem->start_section_nr);
661 const unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block;
662 struct zone *zone, *matching_zone = NULL;
663 pg_data_t *pgdat = NODE_DATA(nid);
664 int i;
665
666 /*
667 * This logic only works for early memory, when the applicable zones
668 * already span the memory block. We don't expect overlapping zones on
669 * a single node for early memory. So if we're told that some PFNs
670 * of a node fall into this memory block, we can assume that all node
671 * zones that intersect with the memory block are actually applicable.
672 * No need to look at the memmap.
673 */
674 for (i = 0; i < MAX_NR_ZONES; i++) {
675 zone = pgdat->node_zones + i;
676 if (!populated_zone(zone))
677 continue;
678 if (!zone_intersects(zone, start_pfn, nr_pages))
679 continue;
680 if (!matching_zone) {
681 matching_zone = zone;
682 continue;
683 }
684 /* Spans multiple zones ... */
685 matching_zone = NULL;
686 break;
687 }
688 return matching_zone;
689}
690
691#ifdef CONFIG_NUMA
692/**
693 * memory_block_add_nid() - Indicate that system RAM falling into this memory
694 * block device (partially) belongs to the given node.
695 * @mem: The memory block device.
696 * @nid: The node id.
697 * @context: The memory initialization context.
698 *
699 * Indicate that system RAM falling into this memory block (partially) belongs
700 * to the given node. If the context indicates ("early") that we are adding the
701 * node during node device subsystem initialization, this will also properly
702 * set/adjust mem->zone based on the zone ranges of the given node.
703 */
704void memory_block_add_nid(struct memory_block *mem, int nid,
705 enum meminit_context context)
706{
707 if (context == MEMINIT_EARLY && mem->nid != nid) {
708 /*
709 * For early memory we have to determine the zone when setting
710 * the node id and handle multiple nodes spanning a single
711 * memory block by indicate via zone == NULL that we're not
712 * dealing with a single zone. So if we're setting the node id
713 * the first time, determine if there is a single zone. If we're
714 * setting the node id a second time to a different node,
715 * invalidate the single detected zone.
716 */
717 if (mem->nid == NUMA_NO_NODE)
718 mem->zone = early_node_zone_for_memory_block(mem, nid);
719 else
720 mem->zone = NULL;
721 }
722
723 /*
724 * If this memory block spans multiple nodes, we only indicate
725 * the last processed node. If we span multiple nodes (not applicable
726 * to hotplugged memory), zone == NULL will prohibit memory offlining
727 * and consequently unplug.
728 */
729 mem->nid = nid;
730}
731#endif
732
733static int add_memory_block(unsigned long block_id, unsigned long state,
734 unsigned long nr_vmemmap_pages,
735 struct memory_group *group)
736{
737 struct memory_block *mem;
738 int ret = 0;
739
740 mem = find_memory_block_by_id(block_id);
741 if (mem) {
742 put_device(&mem->dev);
743 return -EEXIST;
744 }
745 mem = kzalloc(sizeof(*mem), GFP_KERNEL);
746 if (!mem)
747 return -ENOMEM;
748
749 mem->start_section_nr = block_id * sections_per_block;
750 mem->state = state;
751 mem->nid = NUMA_NO_NODE;
752 mem->nr_vmemmap_pages = nr_vmemmap_pages;
753 INIT_LIST_HEAD(&mem->group_next);
754
755#ifndef CONFIG_NUMA
756 if (state == MEM_ONLINE)
757 /*
758 * MEM_ONLINE at this point implies early memory. With NUMA,
759 * we'll determine the zone when setting the node id via
760 * memory_block_add_nid(). Memory hotplug updated the zone
761 * manually when memory onlining/offlining succeeds.
762 */
763 mem->zone = early_node_zone_for_memory_block(mem, NUMA_NO_NODE);
764#endif /* CONFIG_NUMA */
765
766 ret = __add_memory_block(mem);
767 if (ret)
768 return ret;
769
770 if (group) {
771 mem->group = group;
772 list_add(&mem->group_next, &group->memory_blocks);
773 }
774
775 return 0;
776}
777
778static int __init add_boot_memory_block(unsigned long base_section_nr)
779{
780 int section_count = 0;
781 unsigned long nr;
782
783 for (nr = base_section_nr; nr < base_section_nr + sections_per_block;
784 nr++)
785 if (present_section_nr(nr))
786 section_count++;
787
788 if (section_count == 0)
789 return 0;
790 return add_memory_block(memory_block_id(base_section_nr),
791 MEM_ONLINE, 0, NULL);
792}
793
794static int add_hotplug_memory_block(unsigned long block_id,
795 unsigned long nr_vmemmap_pages,
796 struct memory_group *group)
797{
798 return add_memory_block(block_id, MEM_OFFLINE, nr_vmemmap_pages, group);
799}
800
801static void remove_memory_block(struct memory_block *memory)
802{
803 if (WARN_ON_ONCE(memory->dev.bus != &memory_subsys))
804 return;
805
806 WARN_ON(xa_erase(&memory_blocks, memory->dev.id) == NULL);
807
808 if (memory->group) {
809 list_del(&memory->group_next);
810 memory->group = NULL;
811 }
812
813 /* drop the ref. we got via find_memory_block() */
814 put_device(&memory->dev);
815 device_unregister(&memory->dev);
816}
817
818/*
819 * Create memory block devices for the given memory area. Start and size
820 * have to be aligned to memory block granularity. Memory block devices
821 * will be initialized as offline.
822 *
823 * Called under device_hotplug_lock.
824 */
825int create_memory_block_devices(unsigned long start, unsigned long size,
826 unsigned long vmemmap_pages,
827 struct memory_group *group)
828{
829 const unsigned long start_block_id = pfn_to_block_id(PFN_DOWN(start));
830 unsigned long end_block_id = pfn_to_block_id(PFN_DOWN(start + size));
831 struct memory_block *mem;
832 unsigned long block_id;
833 int ret = 0;
834
835 if (WARN_ON_ONCE(!IS_ALIGNED(start, memory_block_size_bytes()) ||
836 !IS_ALIGNED(size, memory_block_size_bytes())))
837 return -EINVAL;
838
839 for (block_id = start_block_id; block_id != end_block_id; block_id++) {
840 ret = add_hotplug_memory_block(block_id, vmemmap_pages, group);
841 if (ret)
842 break;
843 }
844 if (ret) {
845 end_block_id = block_id;
846 for (block_id = start_block_id; block_id != end_block_id;
847 block_id++) {
848 mem = find_memory_block_by_id(block_id);
849 if (WARN_ON_ONCE(!mem))
850 continue;
851 remove_memory_block(mem);
852 }
853 }
854 return ret;
855}
856
857/*
858 * Remove memory block devices for the given memory area. Start and size
859 * have to be aligned to memory block granularity. Memory block devices
860 * have to be offline.
861 *
862 * Called under device_hotplug_lock.
863 */
864void remove_memory_block_devices(unsigned long start, unsigned long size)
865{
866 const unsigned long start_block_id = pfn_to_block_id(PFN_DOWN(start));
867 const unsigned long end_block_id = pfn_to_block_id(PFN_DOWN(start + size));
868 struct memory_block *mem;
869 unsigned long block_id;
870
871 if (WARN_ON_ONCE(!IS_ALIGNED(start, memory_block_size_bytes()) ||
872 !IS_ALIGNED(size, memory_block_size_bytes())))
873 return;
874
875 for (block_id = start_block_id; block_id != end_block_id; block_id++) {
876 mem = find_memory_block_by_id(block_id);
877 if (WARN_ON_ONCE(!mem))
878 continue;
879 num_poisoned_pages_sub(-1UL, memblk_nr_poison(mem));
880 unregister_memory_block_under_nodes(mem);
881 remove_memory_block(mem);
882 }
883}
884
885static struct attribute *memory_root_attrs[] = {
886#ifdef CONFIG_ARCH_MEMORY_PROBE
887 &dev_attr_probe.attr,
888#endif
889
890#ifdef CONFIG_MEMORY_FAILURE
891 &dev_attr_soft_offline_page.attr,
892 &dev_attr_hard_offline_page.attr,
893#endif
894
895 &dev_attr_block_size_bytes.attr,
896 &dev_attr_auto_online_blocks.attr,
897 NULL
898};
899
900static const struct attribute_group memory_root_attr_group = {
901 .attrs = memory_root_attrs,
902};
903
904static const struct attribute_group *memory_root_attr_groups[] = {
905 &memory_root_attr_group,
906 NULL,
907};
908
909/*
910 * Initialize the sysfs support for memory devices. At the time this function
911 * is called, we cannot have concurrent creation/deletion of memory block
912 * devices, the device_hotplug_lock is not needed.
913 */
914void __init memory_dev_init(void)
915{
916 int ret;
917 unsigned long block_sz, nr;
918
919 /* Validate the configured memory block size */
920 block_sz = memory_block_size_bytes();
921 if (!is_power_of_2(block_sz) || block_sz < MIN_MEMORY_BLOCK_SIZE)
922 panic("Memory block size not suitable: 0x%lx\n", block_sz);
923 sections_per_block = block_sz / MIN_MEMORY_BLOCK_SIZE;
924
925 ret = subsys_system_register(&memory_subsys, memory_root_attr_groups);
926 if (ret)
927 panic("%s() failed to register subsystem: %d\n", __func__, ret);
928
929 /*
930 * Create entries for memory sections that were found
931 * during boot and have been initialized
932 */
933 for (nr = 0; nr <= __highest_present_section_nr;
934 nr += sections_per_block) {
935 ret = add_boot_memory_block(nr);
936 if (ret)
937 panic("%s() failed to add memory block: %d\n", __func__,
938 ret);
939 }
940}
941
942/**
943 * walk_memory_blocks - walk through all present memory blocks overlapped
944 * by the range [start, start + size)
945 *
946 * @start: start address of the memory range
947 * @size: size of the memory range
948 * @arg: argument passed to func
949 * @func: callback for each memory section walked
950 *
951 * This function walks through all present memory blocks overlapped by the
952 * range [start, start + size), calling func on each memory block.
953 *
954 * In case func() returns an error, walking is aborted and the error is
955 * returned.
956 *
957 * Called under device_hotplug_lock.
958 */
959int walk_memory_blocks(unsigned long start, unsigned long size,
960 void *arg, walk_memory_blocks_func_t func)
961{
962 const unsigned long start_block_id = phys_to_block_id(start);
963 const unsigned long end_block_id = phys_to_block_id(start + size - 1);
964 struct memory_block *mem;
965 unsigned long block_id;
966 int ret = 0;
967
968 if (!size)
969 return 0;
970
971 for (block_id = start_block_id; block_id <= end_block_id; block_id++) {
972 mem = find_memory_block_by_id(block_id);
973 if (!mem)
974 continue;
975
976 ret = func(mem, arg);
977 put_device(&mem->dev);
978 if (ret)
979 break;
980 }
981 return ret;
982}
983
984struct for_each_memory_block_cb_data {
985 walk_memory_blocks_func_t func;
986 void *arg;
987};
988
989static int for_each_memory_block_cb(struct device *dev, void *data)
990{
991 struct memory_block *mem = to_memory_block(dev);
992 struct for_each_memory_block_cb_data *cb_data = data;
993
994 return cb_data->func(mem, cb_data->arg);
995}
996
997/**
998 * for_each_memory_block - walk through all present memory blocks
999 *
1000 * @arg: argument passed to func
1001 * @func: callback for each memory block walked
1002 *
1003 * This function walks through all present memory blocks, calling func on
1004 * each memory block.
1005 *
1006 * In case func() returns an error, walking is aborted and the error is
1007 * returned.
1008 */
1009int for_each_memory_block(void *arg, walk_memory_blocks_func_t func)
1010{
1011 struct for_each_memory_block_cb_data cb_data = {
1012 .func = func,
1013 .arg = arg,
1014 };
1015
1016 return bus_for_each_dev(&memory_subsys, NULL, &cb_data,
1017 for_each_memory_block_cb);
1018}
1019
1020/*
1021 * This is an internal helper to unify allocation and initialization of
1022 * memory groups. Note that the passed memory group will be copied to a
1023 * dynamically allocated memory group. After this call, the passed
1024 * memory group should no longer be used.
1025 */
1026static int memory_group_register(struct memory_group group)
1027{
1028 struct memory_group *new_group;
1029 uint32_t mgid;
1030 int ret;
1031
1032 if (!node_possible(group.nid))
1033 return -EINVAL;
1034
1035 new_group = kzalloc(sizeof(group), GFP_KERNEL);
1036 if (!new_group)
1037 return -ENOMEM;
1038 *new_group = group;
1039 INIT_LIST_HEAD(&new_group->memory_blocks);
1040
1041 ret = xa_alloc(&memory_groups, &mgid, new_group, xa_limit_31b,
1042 GFP_KERNEL);
1043 if (ret) {
1044 kfree(new_group);
1045 return ret;
1046 } else if (group.is_dynamic) {
1047 xa_set_mark(&memory_groups, mgid, MEMORY_GROUP_MARK_DYNAMIC);
1048 }
1049 return mgid;
1050}
1051
1052/**
1053 * memory_group_register_static() - Register a static memory group.
1054 * @nid: The node id.
1055 * @max_pages: The maximum number of pages we'll have in this static memory
1056 * group.
1057 *
1058 * Register a new static memory group and return the memory group id.
1059 * All memory in the group belongs to a single unit, such as a DIMM. All
1060 * memory belonging to a static memory group is added in one go to be removed
1061 * in one go -- it's static.
1062 *
1063 * Returns an error if out of memory, if the node id is invalid, if no new
1064 * memory groups can be registered, or if max_pages is invalid (0). Otherwise,
1065 * returns the new memory group id.
1066 */
1067int memory_group_register_static(int nid, unsigned long max_pages)
1068{
1069 struct memory_group group = {
1070 .nid = nid,
1071 .s = {
1072 .max_pages = max_pages,
1073 },
1074 };
1075
1076 if (!max_pages)
1077 return -EINVAL;
1078 return memory_group_register(group);
1079}
1080EXPORT_SYMBOL_GPL(memory_group_register_static);
1081
1082/**
1083 * memory_group_register_dynamic() - Register a dynamic memory group.
1084 * @nid: The node id.
1085 * @unit_pages: Unit in pages in which is memory added/removed in this dynamic
1086 * memory group.
1087 *
1088 * Register a new dynamic memory group and return the memory group id.
1089 * Memory within a dynamic memory group is added/removed dynamically
1090 * in unit_pages.
1091 *
1092 * Returns an error if out of memory, if the node id is invalid, if no new
1093 * memory groups can be registered, or if unit_pages is invalid (0, not a
1094 * power of two, smaller than a single memory block). Otherwise, returns the
1095 * new memory group id.
1096 */
1097int memory_group_register_dynamic(int nid, unsigned long unit_pages)
1098{
1099 struct memory_group group = {
1100 .nid = nid,
1101 .is_dynamic = true,
1102 .d = {
1103 .unit_pages = unit_pages,
1104 },
1105 };
1106
1107 if (!unit_pages || !is_power_of_2(unit_pages) ||
1108 unit_pages < PHYS_PFN(memory_block_size_bytes()))
1109 return -EINVAL;
1110 return memory_group_register(group);
1111}
1112EXPORT_SYMBOL_GPL(memory_group_register_dynamic);
1113
1114/**
1115 * memory_group_unregister() - Unregister a memory group.
1116 * @mgid: the memory group id
1117 *
1118 * Unregister a memory group. If any memory block still belongs to this
1119 * memory group, unregistering will fail.
1120 *
1121 * Returns -EINVAL if the memory group id is invalid, returns -EBUSY if some
1122 * memory blocks still belong to this memory group and returns 0 if
1123 * unregistering succeeded.
1124 */
1125int memory_group_unregister(int mgid)
1126{
1127 struct memory_group *group;
1128
1129 if (mgid < 0)
1130 return -EINVAL;
1131
1132 group = xa_load(&memory_groups, mgid);
1133 if (!group)
1134 return -EINVAL;
1135 if (!list_empty(&group->memory_blocks))
1136 return -EBUSY;
1137 xa_erase(&memory_groups, mgid);
1138 kfree(group);
1139 return 0;
1140}
1141EXPORT_SYMBOL_GPL(memory_group_unregister);
1142
1143/*
1144 * This is an internal helper only to be used in core memory hotplug code to
1145 * lookup a memory group. We don't care about locking, as we don't expect a
1146 * memory group to get unregistered while adding memory to it -- because
1147 * the group and the memory is managed by the same driver.
1148 */
1149struct memory_group *memory_group_find_by_id(int mgid)
1150{
1151 return xa_load(&memory_groups, mgid);
1152}
1153
1154/*
1155 * This is an internal helper only to be used in core memory hotplug code to
1156 * walk all dynamic memory groups excluding a given memory group, either
1157 * belonging to a specific node, or belonging to any node.
1158 */
1159int walk_dynamic_memory_groups(int nid, walk_memory_groups_func_t func,
1160 struct memory_group *excluded, void *arg)
1161{
1162 struct memory_group *group;
1163 unsigned long index;
1164 int ret = 0;
1165
1166 xa_for_each_marked(&memory_groups, index, group,
1167 MEMORY_GROUP_MARK_DYNAMIC) {
1168 if (group == excluded)
1169 continue;
1170#ifdef CONFIG_NUMA
1171 if (nid != NUMA_NO_NODE && group->nid != nid)
1172 continue;
1173#endif /* CONFIG_NUMA */
1174 ret = func(group, arg);
1175 if (ret)
1176 break;
1177 }
1178 return ret;
1179}
1180
1181#if defined(CONFIG_MEMORY_FAILURE) && defined(CONFIG_MEMORY_HOTPLUG)
1182void memblk_nr_poison_inc(unsigned long pfn)
1183{
1184 const unsigned long block_id = pfn_to_block_id(pfn);
1185 struct memory_block *mem = find_memory_block_by_id(block_id);
1186
1187 if (mem)
1188 atomic_long_inc(&mem->nr_hwpoison);
1189}
1190
1191void memblk_nr_poison_sub(unsigned long pfn, long i)
1192{
1193 const unsigned long block_id = pfn_to_block_id(pfn);
1194 struct memory_block *mem = find_memory_block_by_id(block_id);
1195
1196 if (mem)
1197 atomic_long_sub(i, &mem->nr_hwpoison);
1198}
1199
1200static unsigned long memblk_nr_poison(struct memory_block *mem)
1201{
1202 return atomic_long_read(&mem->nr_hwpoison);
1203}
1204#endif
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Memory subsystem support
4 *
5 * Written by Matt Tolentino <matthew.e.tolentino@intel.com>
6 * Dave Hansen <haveblue@us.ibm.com>
7 *
8 * This file provides the necessary infrastructure to represent
9 * a SPARSEMEM-memory-model system's physical memory in /sysfs.
10 * All arch-independent code that assumes MEMORY_HOTPLUG requires
11 * SPARSEMEM should be contained here, or in mm/memory_hotplug.c.
12 */
13
14#include <linux/module.h>
15#include <linux/init.h>
16#include <linux/topology.h>
17#include <linux/capability.h>
18#include <linux/device.h>
19#include <linux/memory.h>
20#include <linux/memory_hotplug.h>
21#include <linux/mm.h>
22#include <linux/mutex.h>
23#include <linux/stat.h>
24#include <linux/slab.h>
25
26#include <linux/atomic.h>
27#include <linux/uaccess.h>
28
29static DEFINE_MUTEX(mem_sysfs_mutex);
30
31#define MEMORY_CLASS_NAME "memory"
32
33#define to_memory_block(dev) container_of(dev, struct memory_block, dev)
34
35static int sections_per_block;
36
37static inline int base_memory_block_id(int section_nr)
38{
39 return section_nr / sections_per_block;
40}
41
42static int memory_subsys_online(struct device *dev);
43static int memory_subsys_offline(struct device *dev);
44
45static struct bus_type memory_subsys = {
46 .name = MEMORY_CLASS_NAME,
47 .dev_name = MEMORY_CLASS_NAME,
48 .online = memory_subsys_online,
49 .offline = memory_subsys_offline,
50};
51
52static BLOCKING_NOTIFIER_HEAD(memory_chain);
53
54int register_memory_notifier(struct notifier_block *nb)
55{
56 return blocking_notifier_chain_register(&memory_chain, nb);
57}
58EXPORT_SYMBOL(register_memory_notifier);
59
60void unregister_memory_notifier(struct notifier_block *nb)
61{
62 blocking_notifier_chain_unregister(&memory_chain, nb);
63}
64EXPORT_SYMBOL(unregister_memory_notifier);
65
66static ATOMIC_NOTIFIER_HEAD(memory_isolate_chain);
67
68int register_memory_isolate_notifier(struct notifier_block *nb)
69{
70 return atomic_notifier_chain_register(&memory_isolate_chain, nb);
71}
72EXPORT_SYMBOL(register_memory_isolate_notifier);
73
74void unregister_memory_isolate_notifier(struct notifier_block *nb)
75{
76 atomic_notifier_chain_unregister(&memory_isolate_chain, nb);
77}
78EXPORT_SYMBOL(unregister_memory_isolate_notifier);
79
80static void memory_block_release(struct device *dev)
81{
82 struct memory_block *mem = to_memory_block(dev);
83
84 kfree(mem);
85}
86
87unsigned long __weak memory_block_size_bytes(void)
88{
89 return MIN_MEMORY_BLOCK_SIZE;
90}
91
92static unsigned long get_memory_block_size(void)
93{
94 unsigned long block_sz;
95
96 block_sz = memory_block_size_bytes();
97
98 /* Validate blk_sz is a power of 2 and not less than section size */
99 if ((block_sz & (block_sz - 1)) || (block_sz < MIN_MEMORY_BLOCK_SIZE)) {
100 WARN_ON(1);
101 block_sz = MIN_MEMORY_BLOCK_SIZE;
102 }
103
104 return block_sz;
105}
106
107/*
108 * use this as the physical section index that this memsection
109 * uses.
110 */
111
112static ssize_t show_mem_start_phys_index(struct device *dev,
113 struct device_attribute *attr, char *buf)
114{
115 struct memory_block *mem = to_memory_block(dev);
116 unsigned long phys_index;
117
118 phys_index = mem->start_section_nr / sections_per_block;
119 return sprintf(buf, "%08lx\n", phys_index);
120}
121
122/*
123 * Show whether the section of memory is likely to be hot-removable
124 */
125static ssize_t show_mem_removable(struct device *dev,
126 struct device_attribute *attr, char *buf)
127{
128 unsigned long i, pfn;
129 int ret = 1;
130 struct memory_block *mem = to_memory_block(dev);
131
132 if (mem->state != MEM_ONLINE)
133 goto out;
134
135 for (i = 0; i < sections_per_block; i++) {
136 if (!present_section_nr(mem->start_section_nr + i))
137 continue;
138 pfn = section_nr_to_pfn(mem->start_section_nr + i);
139 ret &= is_mem_section_removable(pfn, PAGES_PER_SECTION);
140 }
141
142out:
143 return sprintf(buf, "%d\n", ret);
144}
145
146/*
147 * online, offline, going offline, etc.
148 */
149static ssize_t show_mem_state(struct device *dev,
150 struct device_attribute *attr, char *buf)
151{
152 struct memory_block *mem = to_memory_block(dev);
153 ssize_t len = 0;
154
155 /*
156 * We can probably put these states in a nice little array
157 * so that they're not open-coded
158 */
159 switch (mem->state) {
160 case MEM_ONLINE:
161 len = sprintf(buf, "online\n");
162 break;
163 case MEM_OFFLINE:
164 len = sprintf(buf, "offline\n");
165 break;
166 case MEM_GOING_OFFLINE:
167 len = sprintf(buf, "going-offline\n");
168 break;
169 default:
170 len = sprintf(buf, "ERROR-UNKNOWN-%ld\n",
171 mem->state);
172 WARN_ON(1);
173 break;
174 }
175
176 return len;
177}
178
179int memory_notify(unsigned long val, void *v)
180{
181 return blocking_notifier_call_chain(&memory_chain, val, v);
182}
183
184int memory_isolate_notify(unsigned long val, void *v)
185{
186 return atomic_notifier_call_chain(&memory_isolate_chain, val, v);
187}
188
189/*
190 * The probe routines leave the pages uninitialized, just as the bootmem code
191 * does. Make sure we do not access them, but instead use only information from
192 * within sections.
193 */
194static bool pages_correctly_probed(unsigned long start_pfn)
195{
196 unsigned long section_nr = pfn_to_section_nr(start_pfn);
197 unsigned long section_nr_end = section_nr + sections_per_block;
198 unsigned long pfn = start_pfn;
199
200 /*
201 * memmap between sections is not contiguous except with
202 * SPARSEMEM_VMEMMAP. We lookup the page once per section
203 * and assume memmap is contiguous within each section
204 */
205 for (; section_nr < section_nr_end; section_nr++) {
206 if (WARN_ON_ONCE(!pfn_valid(pfn)))
207 return false;
208
209 if (!present_section_nr(section_nr)) {
210 pr_warn("section %ld pfn[%lx, %lx) not present",
211 section_nr, pfn, pfn + PAGES_PER_SECTION);
212 return false;
213 } else if (!valid_section_nr(section_nr)) {
214 pr_warn("section %ld pfn[%lx, %lx) no valid memmap",
215 section_nr, pfn, pfn + PAGES_PER_SECTION);
216 return false;
217 } else if (online_section_nr(section_nr)) {
218 pr_warn("section %ld pfn[%lx, %lx) is already online",
219 section_nr, pfn, pfn + PAGES_PER_SECTION);
220 return false;
221 }
222 pfn += PAGES_PER_SECTION;
223 }
224
225 return true;
226}
227
228/*
229 * MEMORY_HOTPLUG depends on SPARSEMEM in mm/Kconfig, so it is
230 * OK to have direct references to sparsemem variables in here.
231 * Must already be protected by mem_hotplug_begin().
232 */
233static int
234memory_block_action(unsigned long phys_index, unsigned long action, int online_type)
235{
236 unsigned long start_pfn;
237 unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block;
238 int ret;
239
240 start_pfn = section_nr_to_pfn(phys_index);
241
242 switch (action) {
243 case MEM_ONLINE:
244 if (!pages_correctly_probed(start_pfn))
245 return -EBUSY;
246
247 ret = online_pages(start_pfn, nr_pages, online_type);
248 break;
249 case MEM_OFFLINE:
250 ret = offline_pages(start_pfn, nr_pages);
251 break;
252 default:
253 WARN(1, KERN_WARNING "%s(%ld, %ld) unknown action: "
254 "%ld\n", __func__, phys_index, action, action);
255 ret = -EINVAL;
256 }
257
258 return ret;
259}
260
261static int memory_block_change_state(struct memory_block *mem,
262 unsigned long to_state, unsigned long from_state_req)
263{
264 int ret = 0;
265
266 if (mem->state != from_state_req)
267 return -EINVAL;
268
269 if (to_state == MEM_OFFLINE)
270 mem->state = MEM_GOING_OFFLINE;
271
272 ret = memory_block_action(mem->start_section_nr, to_state,
273 mem->online_type);
274
275 mem->state = ret ? from_state_req : to_state;
276
277 return ret;
278}
279
280/* The device lock serializes operations on memory_subsys_[online|offline] */
281static int memory_subsys_online(struct device *dev)
282{
283 struct memory_block *mem = to_memory_block(dev);
284 int ret;
285
286 if (mem->state == MEM_ONLINE)
287 return 0;
288
289 /*
290 * If we are called from store_mem_state(), online_type will be
291 * set >= 0 Otherwise we were called from the device online
292 * attribute and need to set the online_type.
293 */
294 if (mem->online_type < 0)
295 mem->online_type = MMOP_ONLINE_KEEP;
296
297 /* Already under protection of mem_hotplug_begin() */
298 ret = memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE);
299
300 /* clear online_type */
301 mem->online_type = -1;
302
303 return ret;
304}
305
306static int memory_subsys_offline(struct device *dev)
307{
308 struct memory_block *mem = to_memory_block(dev);
309
310 if (mem->state == MEM_OFFLINE)
311 return 0;
312
313 /* Can't offline block with non-present sections */
314 if (mem->section_count != sections_per_block)
315 return -EINVAL;
316
317 return memory_block_change_state(mem, MEM_OFFLINE, MEM_ONLINE);
318}
319
320static ssize_t
321store_mem_state(struct device *dev,
322 struct device_attribute *attr, const char *buf, size_t count)
323{
324 struct memory_block *mem = to_memory_block(dev);
325 int ret, online_type;
326
327 ret = lock_device_hotplug_sysfs();
328 if (ret)
329 return ret;
330
331 if (sysfs_streq(buf, "online_kernel"))
332 online_type = MMOP_ONLINE_KERNEL;
333 else if (sysfs_streq(buf, "online_movable"))
334 online_type = MMOP_ONLINE_MOVABLE;
335 else if (sysfs_streq(buf, "online"))
336 online_type = MMOP_ONLINE_KEEP;
337 else if (sysfs_streq(buf, "offline"))
338 online_type = MMOP_OFFLINE;
339 else {
340 ret = -EINVAL;
341 goto err;
342 }
343
344 /*
345 * Memory hotplug needs to hold mem_hotplug_begin() for probe to find
346 * the correct memory block to online before doing device_online(dev),
347 * which will take dev->mutex. Take the lock early to prevent an
348 * inversion, memory_subsys_online() callbacks will be implemented by
349 * assuming it's already protected.
350 */
351 mem_hotplug_begin();
352
353 switch (online_type) {
354 case MMOP_ONLINE_KERNEL:
355 case MMOP_ONLINE_MOVABLE:
356 case MMOP_ONLINE_KEEP:
357 mem->online_type = online_type;
358 ret = device_online(&mem->dev);
359 break;
360 case MMOP_OFFLINE:
361 ret = device_offline(&mem->dev);
362 break;
363 default:
364 ret = -EINVAL; /* should never happen */
365 }
366
367 mem_hotplug_done();
368err:
369 unlock_device_hotplug();
370
371 if (ret < 0)
372 return ret;
373 if (ret)
374 return -EINVAL;
375
376 return count;
377}
378
379/*
380 * phys_device is a bad name for this. What I really want
381 * is a way to differentiate between memory ranges that
382 * are part of physical devices that constitute
383 * a complete removable unit or fru.
384 * i.e. do these ranges belong to the same physical device,
385 * s.t. if I offline all of these sections I can then
386 * remove the physical device?
387 */
388static ssize_t show_phys_device(struct device *dev,
389 struct device_attribute *attr, char *buf)
390{
391 struct memory_block *mem = to_memory_block(dev);
392 return sprintf(buf, "%d\n", mem->phys_device);
393}
394
395#ifdef CONFIG_MEMORY_HOTREMOVE
396static void print_allowed_zone(char *buf, int nid, unsigned long start_pfn,
397 unsigned long nr_pages, int online_type,
398 struct zone *default_zone)
399{
400 struct zone *zone;
401
402 zone = zone_for_pfn_range(online_type, nid, start_pfn, nr_pages);
403 if (zone != default_zone) {
404 strcat(buf, " ");
405 strcat(buf, zone->name);
406 }
407}
408
409static ssize_t show_valid_zones(struct device *dev,
410 struct device_attribute *attr, char *buf)
411{
412 struct memory_block *mem = to_memory_block(dev);
413 unsigned long start_pfn = section_nr_to_pfn(mem->start_section_nr);
414 unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block;
415 unsigned long valid_start_pfn, valid_end_pfn;
416 struct zone *default_zone;
417 int nid;
418
419 /*
420 * The block contains more than one zone can not be offlined.
421 * This can happen e.g. for ZONE_DMA and ZONE_DMA32
422 */
423 if (!test_pages_in_a_zone(start_pfn, start_pfn + nr_pages, &valid_start_pfn, &valid_end_pfn))
424 return sprintf(buf, "none\n");
425
426 start_pfn = valid_start_pfn;
427 nr_pages = valid_end_pfn - start_pfn;
428
429 /*
430 * Check the existing zone. Make sure that we do that only on the
431 * online nodes otherwise the page_zone is not reliable
432 */
433 if (mem->state == MEM_ONLINE) {
434 strcat(buf, page_zone(pfn_to_page(start_pfn))->name);
435 goto out;
436 }
437
438 nid = pfn_to_nid(start_pfn);
439 default_zone = zone_for_pfn_range(MMOP_ONLINE_KEEP, nid, start_pfn, nr_pages);
440 strcat(buf, default_zone->name);
441
442 print_allowed_zone(buf, nid, start_pfn, nr_pages, MMOP_ONLINE_KERNEL,
443 default_zone);
444 print_allowed_zone(buf, nid, start_pfn, nr_pages, MMOP_ONLINE_MOVABLE,
445 default_zone);
446out:
447 strcat(buf, "\n");
448
449 return strlen(buf);
450}
451static DEVICE_ATTR(valid_zones, 0444, show_valid_zones, NULL);
452#endif
453
454static DEVICE_ATTR(phys_index, 0444, show_mem_start_phys_index, NULL);
455static DEVICE_ATTR(state, 0644, show_mem_state, store_mem_state);
456static DEVICE_ATTR(phys_device, 0444, show_phys_device, NULL);
457static DEVICE_ATTR(removable, 0444, show_mem_removable, NULL);
458
459/*
460 * Block size attribute stuff
461 */
462static ssize_t
463print_block_size(struct device *dev, struct device_attribute *attr,
464 char *buf)
465{
466 return sprintf(buf, "%lx\n", get_memory_block_size());
467}
468
469static DEVICE_ATTR(block_size_bytes, 0444, print_block_size, NULL);
470
471/*
472 * Memory auto online policy.
473 */
474
475static ssize_t
476show_auto_online_blocks(struct device *dev, struct device_attribute *attr,
477 char *buf)
478{
479 if (memhp_auto_online)
480 return sprintf(buf, "online\n");
481 else
482 return sprintf(buf, "offline\n");
483}
484
485static ssize_t
486store_auto_online_blocks(struct device *dev, struct device_attribute *attr,
487 const char *buf, size_t count)
488{
489 if (sysfs_streq(buf, "online"))
490 memhp_auto_online = true;
491 else if (sysfs_streq(buf, "offline"))
492 memhp_auto_online = false;
493 else
494 return -EINVAL;
495
496 return count;
497}
498
499static DEVICE_ATTR(auto_online_blocks, 0644, show_auto_online_blocks,
500 store_auto_online_blocks);
501
502/*
503 * Some architectures will have custom drivers to do this, and
504 * will not need to do it from userspace. The fake hot-add code
505 * as well as ppc64 will do all of their discovery in userspace
506 * and will require this interface.
507 */
508#ifdef CONFIG_ARCH_MEMORY_PROBE
509static ssize_t
510memory_probe_store(struct device *dev, struct device_attribute *attr,
511 const char *buf, size_t count)
512{
513 u64 phys_addr;
514 int nid, ret;
515 unsigned long pages_per_block = PAGES_PER_SECTION * sections_per_block;
516
517 ret = kstrtoull(buf, 0, &phys_addr);
518 if (ret)
519 return ret;
520
521 if (phys_addr & ((pages_per_block << PAGE_SHIFT) - 1))
522 return -EINVAL;
523
524 nid = memory_add_physaddr_to_nid(phys_addr);
525 ret = add_memory(nid, phys_addr,
526 MIN_MEMORY_BLOCK_SIZE * sections_per_block);
527
528 if (ret)
529 goto out;
530
531 ret = count;
532out:
533 return ret;
534}
535
536static DEVICE_ATTR(probe, S_IWUSR, NULL, memory_probe_store);
537#endif
538
539#ifdef CONFIG_MEMORY_FAILURE
540/*
541 * Support for offlining pages of memory
542 */
543
544/* Soft offline a page */
545static ssize_t
546store_soft_offline_page(struct device *dev,
547 struct device_attribute *attr,
548 const char *buf, size_t count)
549{
550 int ret;
551 u64 pfn;
552 if (!capable(CAP_SYS_ADMIN))
553 return -EPERM;
554 if (kstrtoull(buf, 0, &pfn) < 0)
555 return -EINVAL;
556 pfn >>= PAGE_SHIFT;
557 if (!pfn_valid(pfn))
558 return -ENXIO;
559 ret = soft_offline_page(pfn_to_page(pfn), 0);
560 return ret == 0 ? count : ret;
561}
562
563/* Forcibly offline a page, including killing processes. */
564static ssize_t
565store_hard_offline_page(struct device *dev,
566 struct device_attribute *attr,
567 const char *buf, size_t count)
568{
569 int ret;
570 u64 pfn;
571 if (!capable(CAP_SYS_ADMIN))
572 return -EPERM;
573 if (kstrtoull(buf, 0, &pfn) < 0)
574 return -EINVAL;
575 pfn >>= PAGE_SHIFT;
576 ret = memory_failure(pfn, 0);
577 return ret ? ret : count;
578}
579
580static DEVICE_ATTR(soft_offline_page, S_IWUSR, NULL, store_soft_offline_page);
581static DEVICE_ATTR(hard_offline_page, S_IWUSR, NULL, store_hard_offline_page);
582#endif
583
584/*
585 * Note that phys_device is optional. It is here to allow for
586 * differentiation between which *physical* devices each
587 * section belongs to...
588 */
589int __weak arch_get_memory_phys_device(unsigned long start_pfn)
590{
591 return 0;
592}
593
594/*
595 * A reference for the returned object is held and the reference for the
596 * hinted object is released.
597 */
598struct memory_block *find_memory_block_hinted(struct mem_section *section,
599 struct memory_block *hint)
600{
601 int block_id = base_memory_block_id(__section_nr(section));
602 struct device *hintdev = hint ? &hint->dev : NULL;
603 struct device *dev;
604
605 dev = subsys_find_device_by_id(&memory_subsys, block_id, hintdev);
606 if (hint)
607 put_device(&hint->dev);
608 if (!dev)
609 return NULL;
610 return to_memory_block(dev);
611}
612
613/*
614 * For now, we have a linear search to go find the appropriate
615 * memory_block corresponding to a particular phys_index. If
616 * this gets to be a real problem, we can always use a radix
617 * tree or something here.
618 *
619 * This could be made generic for all device subsystems.
620 */
621struct memory_block *find_memory_block(struct mem_section *section)
622{
623 return find_memory_block_hinted(section, NULL);
624}
625
626static struct attribute *memory_memblk_attrs[] = {
627 &dev_attr_phys_index.attr,
628 &dev_attr_state.attr,
629 &dev_attr_phys_device.attr,
630 &dev_attr_removable.attr,
631#ifdef CONFIG_MEMORY_HOTREMOVE
632 &dev_attr_valid_zones.attr,
633#endif
634 NULL
635};
636
637static struct attribute_group memory_memblk_attr_group = {
638 .attrs = memory_memblk_attrs,
639};
640
641static const struct attribute_group *memory_memblk_attr_groups[] = {
642 &memory_memblk_attr_group,
643 NULL,
644};
645
646/*
647 * register_memory - Setup a sysfs device for a memory block
648 */
649static
650int register_memory(struct memory_block *memory)
651{
652 memory->dev.bus = &memory_subsys;
653 memory->dev.id = memory->start_section_nr / sections_per_block;
654 memory->dev.release = memory_block_release;
655 memory->dev.groups = memory_memblk_attr_groups;
656 memory->dev.offline = memory->state == MEM_OFFLINE;
657
658 return device_register(&memory->dev);
659}
660
661static int init_memory_block(struct memory_block **memory,
662 struct mem_section *section, unsigned long state)
663{
664 struct memory_block *mem;
665 unsigned long start_pfn;
666 int scn_nr;
667 int ret = 0;
668
669 mem = kzalloc(sizeof(*mem), GFP_KERNEL);
670 if (!mem)
671 return -ENOMEM;
672
673 scn_nr = __section_nr(section);
674 mem->start_section_nr =
675 base_memory_block_id(scn_nr) * sections_per_block;
676 mem->end_section_nr = mem->start_section_nr + sections_per_block - 1;
677 mem->state = state;
678 start_pfn = section_nr_to_pfn(mem->start_section_nr);
679 mem->phys_device = arch_get_memory_phys_device(start_pfn);
680
681 ret = register_memory(mem);
682
683 *memory = mem;
684 return ret;
685}
686
687static int add_memory_block(int base_section_nr)
688{
689 struct memory_block *mem;
690 int i, ret, section_count = 0, section_nr;
691
692 for (i = base_section_nr;
693 (i < base_section_nr + sections_per_block) && i < NR_MEM_SECTIONS;
694 i++) {
695 if (!present_section_nr(i))
696 continue;
697 if (section_count == 0)
698 section_nr = i;
699 section_count++;
700 }
701
702 if (section_count == 0)
703 return 0;
704 ret = init_memory_block(&mem, __nr_to_section(section_nr), MEM_ONLINE);
705 if (ret)
706 return ret;
707 mem->section_count = section_count;
708 return 0;
709}
710
711/*
712 * need an interface for the VM to add new memory regions,
713 * but without onlining it.
714 */
715int hotplug_memory_register(int nid, struct mem_section *section)
716{
717 int ret = 0;
718 struct memory_block *mem;
719
720 mutex_lock(&mem_sysfs_mutex);
721
722 mem = find_memory_block(section);
723 if (mem) {
724 mem->section_count++;
725 put_device(&mem->dev);
726 } else {
727 ret = init_memory_block(&mem, section, MEM_OFFLINE);
728 if (ret)
729 goto out;
730 mem->section_count++;
731 }
732
733 if (mem->section_count == sections_per_block)
734 ret = register_mem_sect_under_node(mem, nid, false);
735out:
736 mutex_unlock(&mem_sysfs_mutex);
737 return ret;
738}
739
740#ifdef CONFIG_MEMORY_HOTREMOVE
741static void
742unregister_memory(struct memory_block *memory)
743{
744 BUG_ON(memory->dev.bus != &memory_subsys);
745
746 /* drop the ref. we got in remove_memory_block() */
747 put_device(&memory->dev);
748 device_unregister(&memory->dev);
749}
750
751static int remove_memory_section(unsigned long node_id,
752 struct mem_section *section, int phys_device)
753{
754 struct memory_block *mem;
755
756 mutex_lock(&mem_sysfs_mutex);
757
758 /*
759 * Some users of the memory hotplug do not want/need memblock to
760 * track all sections. Skip over those.
761 */
762 mem = find_memory_block(section);
763 if (!mem)
764 goto out_unlock;
765
766 unregister_mem_sect_under_nodes(mem, __section_nr(section));
767
768 mem->section_count--;
769 if (mem->section_count == 0)
770 unregister_memory(mem);
771 else
772 put_device(&mem->dev);
773
774out_unlock:
775 mutex_unlock(&mem_sysfs_mutex);
776 return 0;
777}
778
779int unregister_memory_section(struct mem_section *section)
780{
781 if (!present_section(section))
782 return -EINVAL;
783
784 return remove_memory_section(0, section, 0);
785}
786#endif /* CONFIG_MEMORY_HOTREMOVE */
787
788/* return true if the memory block is offlined, otherwise, return false */
789bool is_memblock_offlined(struct memory_block *mem)
790{
791 return mem->state == MEM_OFFLINE;
792}
793
794static struct attribute *memory_root_attrs[] = {
795#ifdef CONFIG_ARCH_MEMORY_PROBE
796 &dev_attr_probe.attr,
797#endif
798
799#ifdef CONFIG_MEMORY_FAILURE
800 &dev_attr_soft_offline_page.attr,
801 &dev_attr_hard_offline_page.attr,
802#endif
803
804 &dev_attr_block_size_bytes.attr,
805 &dev_attr_auto_online_blocks.attr,
806 NULL
807};
808
809static struct attribute_group memory_root_attr_group = {
810 .attrs = memory_root_attrs,
811};
812
813static const struct attribute_group *memory_root_attr_groups[] = {
814 &memory_root_attr_group,
815 NULL,
816};
817
818/*
819 * Initialize the sysfs support for memory devices...
820 */
821int __init memory_dev_init(void)
822{
823 unsigned int i;
824 int ret;
825 int err;
826 unsigned long block_sz;
827
828 ret = subsys_system_register(&memory_subsys, memory_root_attr_groups);
829 if (ret)
830 goto out;
831
832 block_sz = get_memory_block_size();
833 sections_per_block = block_sz / MIN_MEMORY_BLOCK_SIZE;
834
835 /*
836 * Create entries for memory sections that were found
837 * during boot and have been initialized
838 */
839 mutex_lock(&mem_sysfs_mutex);
840 for (i = 0; i <= __highest_present_section_nr;
841 i += sections_per_block) {
842 err = add_memory_block(i);
843 if (!ret)
844 ret = err;
845 }
846 mutex_unlock(&mem_sysfs_mutex);
847
848out:
849 if (ret)
850 printk(KERN_ERR "%s() failed: %d\n", __func__, ret);
851 return ret;
852}