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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 const 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 /* Verify that the altmap is freed */
109 WARN_ON(mem->altmap);
110 kfree(mem);
111}
112
113unsigned long __weak memory_block_size_bytes(void)
114{
115 return MIN_MEMORY_BLOCK_SIZE;
116}
117EXPORT_SYMBOL_GPL(memory_block_size_bytes);
118
119/* Show the memory block ID, relative to the memory block size */
120static ssize_t phys_index_show(struct device *dev,
121 struct device_attribute *attr, char *buf)
122{
123 struct memory_block *mem = to_memory_block(dev);
124
125 return sysfs_emit(buf, "%08lx\n", memory_block_id(mem->start_section_nr));
126}
127
128/*
129 * Legacy interface that we cannot remove. Always indicate "removable"
130 * with CONFIG_MEMORY_HOTREMOVE - bad heuristic.
131 */
132static ssize_t removable_show(struct device *dev, struct device_attribute *attr,
133 char *buf)
134{
135 return sysfs_emit(buf, "%d\n", (int)IS_ENABLED(CONFIG_MEMORY_HOTREMOVE));
136}
137
138/*
139 * online, offline, going offline, etc.
140 */
141static ssize_t state_show(struct device *dev, struct device_attribute *attr,
142 char *buf)
143{
144 struct memory_block *mem = to_memory_block(dev);
145 const char *output;
146
147 /*
148 * We can probably put these states in a nice little array
149 * so that they're not open-coded
150 */
151 switch (mem->state) {
152 case MEM_ONLINE:
153 output = "online";
154 break;
155 case MEM_OFFLINE:
156 output = "offline";
157 break;
158 case MEM_GOING_OFFLINE:
159 output = "going-offline";
160 break;
161 default:
162 WARN_ON(1);
163 return sysfs_emit(buf, "ERROR-UNKNOWN-%ld\n", mem->state);
164 }
165
166 return sysfs_emit(buf, "%s\n", output);
167}
168
169int memory_notify(unsigned long val, void *v)
170{
171 return blocking_notifier_call_chain(&memory_chain, val, v);
172}
173
174#if defined(CONFIG_MEMORY_FAILURE) && defined(CONFIG_MEMORY_HOTPLUG)
175static unsigned long memblk_nr_poison(struct memory_block *mem);
176#else
177static inline unsigned long memblk_nr_poison(struct memory_block *mem)
178{
179 return 0;
180}
181#endif
182
183/*
184 * Must acquire mem_hotplug_lock in write mode.
185 */
186static int memory_block_online(struct memory_block *mem)
187{
188 unsigned long start_pfn = section_nr_to_pfn(mem->start_section_nr);
189 unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block;
190 unsigned long nr_vmemmap_pages = 0;
191 struct zone *zone;
192 int ret;
193
194 if (memblk_nr_poison(mem))
195 return -EHWPOISON;
196
197 zone = zone_for_pfn_range(mem->online_type, mem->nid, mem->group,
198 start_pfn, nr_pages);
199
200 /*
201 * Although vmemmap pages have a different lifecycle than the pages
202 * they describe (they remain until the memory is unplugged), doing
203 * their initialization and accounting at memory onlining/offlining
204 * stage helps to keep accounting easier to follow - e.g vmemmaps
205 * belong to the same zone as the memory they backed.
206 */
207 if (mem->altmap)
208 nr_vmemmap_pages = mem->altmap->free;
209
210 mem_hotplug_begin();
211 if (nr_vmemmap_pages) {
212 ret = mhp_init_memmap_on_memory(start_pfn, nr_vmemmap_pages, zone);
213 if (ret)
214 goto out;
215 }
216
217 ret = online_pages(start_pfn + nr_vmemmap_pages,
218 nr_pages - nr_vmemmap_pages, zone, mem->group);
219 if (ret) {
220 if (nr_vmemmap_pages)
221 mhp_deinit_memmap_on_memory(start_pfn, nr_vmemmap_pages);
222 goto out;
223 }
224
225 /*
226 * Account once onlining succeeded. If the zone was unpopulated, it is
227 * now already properly populated.
228 */
229 if (nr_vmemmap_pages)
230 adjust_present_page_count(pfn_to_page(start_pfn), mem->group,
231 nr_vmemmap_pages);
232
233 mem->zone = zone;
234out:
235 mem_hotplug_done();
236 return ret;
237}
238
239/*
240 * Must acquire mem_hotplug_lock in write mode.
241 */
242static int memory_block_offline(struct memory_block *mem)
243{
244 unsigned long start_pfn = section_nr_to_pfn(mem->start_section_nr);
245 unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block;
246 unsigned long nr_vmemmap_pages = 0;
247 int ret;
248
249 if (!mem->zone)
250 return -EINVAL;
251
252 /*
253 * Unaccount before offlining, such that unpopulated zone and kthreads
254 * can properly be torn down in offline_pages().
255 */
256 if (mem->altmap)
257 nr_vmemmap_pages = mem->altmap->free;
258
259 mem_hotplug_begin();
260 if (nr_vmemmap_pages)
261 adjust_present_page_count(pfn_to_page(start_pfn), mem->group,
262 -nr_vmemmap_pages);
263
264 ret = offline_pages(start_pfn + nr_vmemmap_pages,
265 nr_pages - nr_vmemmap_pages, mem->zone, mem->group);
266 if (ret) {
267 /* offline_pages() failed. Account back. */
268 if (nr_vmemmap_pages)
269 adjust_present_page_count(pfn_to_page(start_pfn),
270 mem->group, nr_vmemmap_pages);
271 goto out;
272 }
273
274 if (nr_vmemmap_pages)
275 mhp_deinit_memmap_on_memory(start_pfn, nr_vmemmap_pages);
276
277 mem->zone = NULL;
278out:
279 mem_hotplug_done();
280 return ret;
281}
282
283/*
284 * MEMORY_HOTPLUG depends on SPARSEMEM in mm/Kconfig, so it is
285 * OK to have direct references to sparsemem variables in here.
286 */
287static int
288memory_block_action(struct memory_block *mem, unsigned long action)
289{
290 int ret;
291
292 switch (action) {
293 case MEM_ONLINE:
294 ret = memory_block_online(mem);
295 break;
296 case MEM_OFFLINE:
297 ret = memory_block_offline(mem);
298 break;
299 default:
300 WARN(1, KERN_WARNING "%s(%ld, %ld) unknown action: "
301 "%ld\n", __func__, mem->start_section_nr, action, action);
302 ret = -EINVAL;
303 }
304
305 return ret;
306}
307
308static int memory_block_change_state(struct memory_block *mem,
309 unsigned long to_state, unsigned long from_state_req)
310{
311 int ret = 0;
312
313 if (mem->state != from_state_req)
314 return -EINVAL;
315
316 if (to_state == MEM_OFFLINE)
317 mem->state = MEM_GOING_OFFLINE;
318
319 ret = memory_block_action(mem, to_state);
320 mem->state = ret ? from_state_req : to_state;
321
322 return ret;
323}
324
325/* The device lock serializes operations on memory_subsys_[online|offline] */
326static int memory_subsys_online(struct device *dev)
327{
328 struct memory_block *mem = to_memory_block(dev);
329 int ret;
330
331 if (mem->state == MEM_ONLINE)
332 return 0;
333
334 /*
335 * When called via device_online() without configuring the online_type,
336 * we want to default to MMOP_ONLINE.
337 */
338 if (mem->online_type == MMOP_OFFLINE)
339 mem->online_type = MMOP_ONLINE;
340
341 ret = memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE);
342 mem->online_type = MMOP_OFFLINE;
343
344 return ret;
345}
346
347static int memory_subsys_offline(struct device *dev)
348{
349 struct memory_block *mem = to_memory_block(dev);
350
351 if (mem->state == MEM_OFFLINE)
352 return 0;
353
354 return memory_block_change_state(mem, MEM_OFFLINE, MEM_ONLINE);
355}
356
357static ssize_t state_store(struct device *dev, struct device_attribute *attr,
358 const char *buf, size_t count)
359{
360 const int online_type = mhp_online_type_from_str(buf);
361 struct memory_block *mem = to_memory_block(dev);
362 int ret;
363
364 if (online_type < 0)
365 return -EINVAL;
366
367 ret = lock_device_hotplug_sysfs();
368 if (ret)
369 return ret;
370
371 switch (online_type) {
372 case MMOP_ONLINE_KERNEL:
373 case MMOP_ONLINE_MOVABLE:
374 case MMOP_ONLINE:
375 /* mem->online_type is protected by device_hotplug_lock */
376 mem->online_type = online_type;
377 ret = device_online(&mem->dev);
378 break;
379 case MMOP_OFFLINE:
380 ret = device_offline(&mem->dev);
381 break;
382 default:
383 ret = -EINVAL; /* should never happen */
384 }
385
386 unlock_device_hotplug();
387
388 if (ret < 0)
389 return ret;
390 if (ret)
391 return -EINVAL;
392
393 return count;
394}
395
396/*
397 * Legacy interface that we cannot remove: s390x exposes the storage increment
398 * covered by a memory block, allowing for identifying which memory blocks
399 * comprise a storage increment. Since a memory block spans complete
400 * storage increments nowadays, this interface is basically unused. Other
401 * archs never exposed != 0.
402 */
403static ssize_t phys_device_show(struct device *dev,
404 struct device_attribute *attr, char *buf)
405{
406 struct memory_block *mem = to_memory_block(dev);
407 unsigned long start_pfn = section_nr_to_pfn(mem->start_section_nr);
408
409 return sysfs_emit(buf, "%d\n",
410 arch_get_memory_phys_device(start_pfn));
411}
412
413#ifdef CONFIG_MEMORY_HOTREMOVE
414static int print_allowed_zone(char *buf, int len, int nid,
415 struct memory_group *group,
416 unsigned long start_pfn, unsigned long nr_pages,
417 int online_type, struct zone *default_zone)
418{
419 struct zone *zone;
420
421 zone = zone_for_pfn_range(online_type, nid, group, start_pfn, nr_pages);
422 if (zone == default_zone)
423 return 0;
424
425 return sysfs_emit_at(buf, len, " %s", zone->name);
426}
427
428static ssize_t valid_zones_show(struct device *dev,
429 struct device_attribute *attr, char *buf)
430{
431 struct memory_block *mem = to_memory_block(dev);
432 unsigned long start_pfn = section_nr_to_pfn(mem->start_section_nr);
433 unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block;
434 struct memory_group *group = mem->group;
435 struct zone *default_zone;
436 int nid = mem->nid;
437 int len = 0;
438
439 /*
440 * Check the existing zone. Make sure that we do that only on the
441 * online nodes otherwise the page_zone is not reliable
442 */
443 if (mem->state == MEM_ONLINE) {
444 /*
445 * If !mem->zone, the memory block spans multiple zones and
446 * cannot get offlined.
447 */
448 default_zone = mem->zone;
449 if (!default_zone)
450 return sysfs_emit(buf, "%s\n", "none");
451 len += sysfs_emit_at(buf, len, "%s", default_zone->name);
452 goto out;
453 }
454
455 default_zone = zone_for_pfn_range(MMOP_ONLINE, nid, group,
456 start_pfn, nr_pages);
457
458 len += sysfs_emit_at(buf, len, "%s", default_zone->name);
459 len += print_allowed_zone(buf, len, nid, group, start_pfn, nr_pages,
460 MMOP_ONLINE_KERNEL, default_zone);
461 len += print_allowed_zone(buf, len, nid, group, start_pfn, nr_pages,
462 MMOP_ONLINE_MOVABLE, default_zone);
463out:
464 len += sysfs_emit_at(buf, len, "\n");
465 return len;
466}
467static DEVICE_ATTR_RO(valid_zones);
468#endif
469
470static DEVICE_ATTR_RO(phys_index);
471static DEVICE_ATTR_RW(state);
472static DEVICE_ATTR_RO(phys_device);
473static DEVICE_ATTR_RO(removable);
474
475/*
476 * Show the memory block size (shared by all memory blocks).
477 */
478static ssize_t block_size_bytes_show(struct device *dev,
479 struct device_attribute *attr, char *buf)
480{
481 return sysfs_emit(buf, "%lx\n", memory_block_size_bytes());
482}
483
484static DEVICE_ATTR_RO(block_size_bytes);
485
486/*
487 * Memory auto online policy.
488 */
489
490static ssize_t auto_online_blocks_show(struct device *dev,
491 struct device_attribute *attr, char *buf)
492{
493 return sysfs_emit(buf, "%s\n",
494 online_type_to_str[mhp_default_online_type]);
495}
496
497static ssize_t auto_online_blocks_store(struct device *dev,
498 struct device_attribute *attr,
499 const char *buf, size_t count)
500{
501 const int online_type = mhp_online_type_from_str(buf);
502
503 if (online_type < 0)
504 return -EINVAL;
505
506 mhp_default_online_type = online_type;
507 return count;
508}
509
510static DEVICE_ATTR_RW(auto_online_blocks);
511
512#ifdef CONFIG_CRASH_HOTPLUG
513#include <linux/kexec.h>
514static ssize_t crash_hotplug_show(struct device *dev,
515 struct device_attribute *attr, char *buf)
516{
517 return sysfs_emit(buf, "%d\n", crash_hotplug_memory_support());
518}
519static DEVICE_ATTR_RO(crash_hotplug);
520#endif
521
522/*
523 * Some architectures will have custom drivers to do this, and
524 * will not need to do it from userspace. The fake hot-add code
525 * as well as ppc64 will do all of their discovery in userspace
526 * and will require this interface.
527 */
528#ifdef CONFIG_ARCH_MEMORY_PROBE
529static ssize_t probe_store(struct device *dev, struct device_attribute *attr,
530 const char *buf, size_t count)
531{
532 u64 phys_addr;
533 int nid, ret;
534 unsigned long pages_per_block = PAGES_PER_SECTION * sections_per_block;
535
536 ret = kstrtoull(buf, 0, &phys_addr);
537 if (ret)
538 return ret;
539
540 if (phys_addr & ((pages_per_block << PAGE_SHIFT) - 1))
541 return -EINVAL;
542
543 ret = lock_device_hotplug_sysfs();
544 if (ret)
545 return ret;
546
547 nid = memory_add_physaddr_to_nid(phys_addr);
548 ret = __add_memory(nid, phys_addr,
549 MIN_MEMORY_BLOCK_SIZE * sections_per_block,
550 MHP_NONE);
551
552 if (ret)
553 goto out;
554
555 ret = count;
556out:
557 unlock_device_hotplug();
558 return ret;
559}
560
561static DEVICE_ATTR_WO(probe);
562#endif
563
564#ifdef CONFIG_MEMORY_FAILURE
565/*
566 * Support for offlining pages of memory
567 */
568
569/* Soft offline a page */
570static ssize_t soft_offline_page_store(struct device *dev,
571 struct device_attribute *attr,
572 const char *buf, size_t count)
573{
574 int ret;
575 u64 pfn;
576 if (!capable(CAP_SYS_ADMIN))
577 return -EPERM;
578 if (kstrtoull(buf, 0, &pfn) < 0)
579 return -EINVAL;
580 pfn >>= PAGE_SHIFT;
581 ret = soft_offline_page(pfn, 0);
582 return ret == 0 ? count : ret;
583}
584
585/* Forcibly offline a page, including killing processes. */
586static ssize_t hard_offline_page_store(struct device *dev,
587 struct device_attribute *attr,
588 const char *buf, size_t count)
589{
590 int ret;
591 u64 pfn;
592 if (!capable(CAP_SYS_ADMIN))
593 return -EPERM;
594 if (kstrtoull(buf, 0, &pfn) < 0)
595 return -EINVAL;
596 pfn >>= PAGE_SHIFT;
597 ret = memory_failure(pfn, MF_SW_SIMULATED);
598 if (ret == -EOPNOTSUPP)
599 ret = 0;
600 return ret ? ret : count;
601}
602
603static DEVICE_ATTR_WO(soft_offline_page);
604static DEVICE_ATTR_WO(hard_offline_page);
605#endif
606
607/* See phys_device_show(). */
608int __weak arch_get_memory_phys_device(unsigned long start_pfn)
609{
610 return 0;
611}
612
613/*
614 * A reference for the returned memory block device is acquired.
615 *
616 * Called under device_hotplug_lock.
617 */
618static struct memory_block *find_memory_block_by_id(unsigned long block_id)
619{
620 struct memory_block *mem;
621
622 mem = xa_load(&memory_blocks, block_id);
623 if (mem)
624 get_device(&mem->dev);
625 return mem;
626}
627
628/*
629 * Called under device_hotplug_lock.
630 */
631struct memory_block *find_memory_block(unsigned long section_nr)
632{
633 unsigned long block_id = memory_block_id(section_nr);
634
635 return find_memory_block_by_id(block_id);
636}
637
638static struct attribute *memory_memblk_attrs[] = {
639 &dev_attr_phys_index.attr,
640 &dev_attr_state.attr,
641 &dev_attr_phys_device.attr,
642 &dev_attr_removable.attr,
643#ifdef CONFIG_MEMORY_HOTREMOVE
644 &dev_attr_valid_zones.attr,
645#endif
646 NULL
647};
648
649static const struct attribute_group memory_memblk_attr_group = {
650 .attrs = memory_memblk_attrs,
651};
652
653static const struct attribute_group *memory_memblk_attr_groups[] = {
654 &memory_memblk_attr_group,
655 NULL,
656};
657
658static int __add_memory_block(struct memory_block *memory)
659{
660 int ret;
661
662 memory->dev.bus = &memory_subsys;
663 memory->dev.id = memory->start_section_nr / sections_per_block;
664 memory->dev.release = memory_block_release;
665 memory->dev.groups = memory_memblk_attr_groups;
666 memory->dev.offline = memory->state == MEM_OFFLINE;
667
668 ret = device_register(&memory->dev);
669 if (ret) {
670 put_device(&memory->dev);
671 return ret;
672 }
673 ret = xa_err(xa_store(&memory_blocks, memory->dev.id, memory,
674 GFP_KERNEL));
675 if (ret)
676 device_unregister(&memory->dev);
677
678 return ret;
679}
680
681static struct zone *early_node_zone_for_memory_block(struct memory_block *mem,
682 int nid)
683{
684 const unsigned long start_pfn = section_nr_to_pfn(mem->start_section_nr);
685 const unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block;
686 struct zone *zone, *matching_zone = NULL;
687 pg_data_t *pgdat = NODE_DATA(nid);
688 int i;
689
690 /*
691 * This logic only works for early memory, when the applicable zones
692 * already span the memory block. We don't expect overlapping zones on
693 * a single node for early memory. So if we're told that some PFNs
694 * of a node fall into this memory block, we can assume that all node
695 * zones that intersect with the memory block are actually applicable.
696 * No need to look at the memmap.
697 */
698 for (i = 0; i < MAX_NR_ZONES; i++) {
699 zone = pgdat->node_zones + i;
700 if (!populated_zone(zone))
701 continue;
702 if (!zone_intersects(zone, start_pfn, nr_pages))
703 continue;
704 if (!matching_zone) {
705 matching_zone = zone;
706 continue;
707 }
708 /* Spans multiple zones ... */
709 matching_zone = NULL;
710 break;
711 }
712 return matching_zone;
713}
714
715#ifdef CONFIG_NUMA
716/**
717 * memory_block_add_nid() - Indicate that system RAM falling into this memory
718 * block device (partially) belongs to the given node.
719 * @mem: The memory block device.
720 * @nid: The node id.
721 * @context: The memory initialization context.
722 *
723 * Indicate that system RAM falling into this memory block (partially) belongs
724 * to the given node. If the context indicates ("early") that we are adding the
725 * node during node device subsystem initialization, this will also properly
726 * set/adjust mem->zone based on the zone ranges of the given node.
727 */
728void memory_block_add_nid(struct memory_block *mem, int nid,
729 enum meminit_context context)
730{
731 if (context == MEMINIT_EARLY && mem->nid != nid) {
732 /*
733 * For early memory we have to determine the zone when setting
734 * the node id and handle multiple nodes spanning a single
735 * memory block by indicate via zone == NULL that we're not
736 * dealing with a single zone. So if we're setting the node id
737 * the first time, determine if there is a single zone. If we're
738 * setting the node id a second time to a different node,
739 * invalidate the single detected zone.
740 */
741 if (mem->nid == NUMA_NO_NODE)
742 mem->zone = early_node_zone_for_memory_block(mem, nid);
743 else
744 mem->zone = NULL;
745 }
746
747 /*
748 * If this memory block spans multiple nodes, we only indicate
749 * the last processed node. If we span multiple nodes (not applicable
750 * to hotplugged memory), zone == NULL will prohibit memory offlining
751 * and consequently unplug.
752 */
753 mem->nid = nid;
754}
755#endif
756
757static int add_memory_block(unsigned long block_id, unsigned long state,
758 struct vmem_altmap *altmap,
759 struct memory_group *group)
760{
761 struct memory_block *mem;
762 int ret = 0;
763
764 mem = find_memory_block_by_id(block_id);
765 if (mem) {
766 put_device(&mem->dev);
767 return -EEXIST;
768 }
769 mem = kzalloc(sizeof(*mem), GFP_KERNEL);
770 if (!mem)
771 return -ENOMEM;
772
773 mem->start_section_nr = block_id * sections_per_block;
774 mem->state = state;
775 mem->nid = NUMA_NO_NODE;
776 mem->altmap = altmap;
777 INIT_LIST_HEAD(&mem->group_next);
778
779#ifndef CONFIG_NUMA
780 if (state == MEM_ONLINE)
781 /*
782 * MEM_ONLINE at this point implies early memory. With NUMA,
783 * we'll determine the zone when setting the node id via
784 * memory_block_add_nid(). Memory hotplug updated the zone
785 * manually when memory onlining/offlining succeeds.
786 */
787 mem->zone = early_node_zone_for_memory_block(mem, NUMA_NO_NODE);
788#endif /* CONFIG_NUMA */
789
790 ret = __add_memory_block(mem);
791 if (ret)
792 return ret;
793
794 if (group) {
795 mem->group = group;
796 list_add(&mem->group_next, &group->memory_blocks);
797 }
798
799 return 0;
800}
801
802static int __init add_boot_memory_block(unsigned long base_section_nr)
803{
804 int section_count = 0;
805 unsigned long nr;
806
807 for (nr = base_section_nr; nr < base_section_nr + sections_per_block;
808 nr++)
809 if (present_section_nr(nr))
810 section_count++;
811
812 if (section_count == 0)
813 return 0;
814 return add_memory_block(memory_block_id(base_section_nr),
815 MEM_ONLINE, NULL, NULL);
816}
817
818static int add_hotplug_memory_block(unsigned long block_id,
819 struct vmem_altmap *altmap,
820 struct memory_group *group)
821{
822 return add_memory_block(block_id, MEM_OFFLINE, altmap, group);
823}
824
825static void remove_memory_block(struct memory_block *memory)
826{
827 if (WARN_ON_ONCE(memory->dev.bus != &memory_subsys))
828 return;
829
830 WARN_ON(xa_erase(&memory_blocks, memory->dev.id) == NULL);
831
832 if (memory->group) {
833 list_del(&memory->group_next);
834 memory->group = NULL;
835 }
836
837 /* drop the ref. we got via find_memory_block() */
838 put_device(&memory->dev);
839 device_unregister(&memory->dev);
840}
841
842/*
843 * Create memory block devices for the given memory area. Start and size
844 * have to be aligned to memory block granularity. Memory block devices
845 * will be initialized as offline.
846 *
847 * Called under device_hotplug_lock.
848 */
849int create_memory_block_devices(unsigned long start, unsigned long size,
850 struct vmem_altmap *altmap,
851 struct memory_group *group)
852{
853 const unsigned long start_block_id = pfn_to_block_id(PFN_DOWN(start));
854 unsigned long end_block_id = pfn_to_block_id(PFN_DOWN(start + size));
855 struct memory_block *mem;
856 unsigned long block_id;
857 int ret = 0;
858
859 if (WARN_ON_ONCE(!IS_ALIGNED(start, memory_block_size_bytes()) ||
860 !IS_ALIGNED(size, memory_block_size_bytes())))
861 return -EINVAL;
862
863 for (block_id = start_block_id; block_id != end_block_id; block_id++) {
864 ret = add_hotplug_memory_block(block_id, altmap, group);
865 if (ret)
866 break;
867 }
868 if (ret) {
869 end_block_id = block_id;
870 for (block_id = start_block_id; block_id != end_block_id;
871 block_id++) {
872 mem = find_memory_block_by_id(block_id);
873 if (WARN_ON_ONCE(!mem))
874 continue;
875 remove_memory_block(mem);
876 }
877 }
878 return ret;
879}
880
881/*
882 * Remove memory block devices for the given memory area. Start and size
883 * have to be aligned to memory block granularity. Memory block devices
884 * have to be offline.
885 *
886 * Called under device_hotplug_lock.
887 */
888void remove_memory_block_devices(unsigned long start, unsigned long size)
889{
890 const unsigned long start_block_id = pfn_to_block_id(PFN_DOWN(start));
891 const unsigned long end_block_id = pfn_to_block_id(PFN_DOWN(start + size));
892 struct memory_block *mem;
893 unsigned long block_id;
894
895 if (WARN_ON_ONCE(!IS_ALIGNED(start, memory_block_size_bytes()) ||
896 !IS_ALIGNED(size, memory_block_size_bytes())))
897 return;
898
899 for (block_id = start_block_id; block_id != end_block_id; block_id++) {
900 mem = find_memory_block_by_id(block_id);
901 if (WARN_ON_ONCE(!mem))
902 continue;
903 num_poisoned_pages_sub(-1UL, memblk_nr_poison(mem));
904 unregister_memory_block_under_nodes(mem);
905 remove_memory_block(mem);
906 }
907}
908
909static struct attribute *memory_root_attrs[] = {
910#ifdef CONFIG_ARCH_MEMORY_PROBE
911 &dev_attr_probe.attr,
912#endif
913
914#ifdef CONFIG_MEMORY_FAILURE
915 &dev_attr_soft_offline_page.attr,
916 &dev_attr_hard_offline_page.attr,
917#endif
918
919 &dev_attr_block_size_bytes.attr,
920 &dev_attr_auto_online_blocks.attr,
921#ifdef CONFIG_CRASH_HOTPLUG
922 &dev_attr_crash_hotplug.attr,
923#endif
924 NULL
925};
926
927static const struct attribute_group memory_root_attr_group = {
928 .attrs = memory_root_attrs,
929};
930
931static const struct attribute_group *memory_root_attr_groups[] = {
932 &memory_root_attr_group,
933 NULL,
934};
935
936/*
937 * Initialize the sysfs support for memory devices. At the time this function
938 * is called, we cannot have concurrent creation/deletion of memory block
939 * devices, the device_hotplug_lock is not needed.
940 */
941void __init memory_dev_init(void)
942{
943 int ret;
944 unsigned long block_sz, nr;
945
946 /* Validate the configured memory block size */
947 block_sz = memory_block_size_bytes();
948 if (!is_power_of_2(block_sz) || block_sz < MIN_MEMORY_BLOCK_SIZE)
949 panic("Memory block size not suitable: 0x%lx\n", block_sz);
950 sections_per_block = block_sz / MIN_MEMORY_BLOCK_SIZE;
951
952 ret = subsys_system_register(&memory_subsys, memory_root_attr_groups);
953 if (ret)
954 panic("%s() failed to register subsystem: %d\n", __func__, ret);
955
956 /*
957 * Create entries for memory sections that were found
958 * during boot and have been initialized
959 */
960 for (nr = 0; nr <= __highest_present_section_nr;
961 nr += sections_per_block) {
962 ret = add_boot_memory_block(nr);
963 if (ret)
964 panic("%s() failed to add memory block: %d\n", __func__,
965 ret);
966 }
967}
968
969/**
970 * walk_memory_blocks - walk through all present memory blocks overlapped
971 * by the range [start, start + size)
972 *
973 * @start: start address of the memory range
974 * @size: size of the memory range
975 * @arg: argument passed to func
976 * @func: callback for each memory section walked
977 *
978 * This function walks through all present memory blocks overlapped by the
979 * range [start, start + size), calling func on each memory block.
980 *
981 * In case func() returns an error, walking is aborted and the error is
982 * returned.
983 *
984 * Called under device_hotplug_lock.
985 */
986int walk_memory_blocks(unsigned long start, unsigned long size,
987 void *arg, walk_memory_blocks_func_t func)
988{
989 const unsigned long start_block_id = phys_to_block_id(start);
990 const unsigned long end_block_id = phys_to_block_id(start + size - 1);
991 struct memory_block *mem;
992 unsigned long block_id;
993 int ret = 0;
994
995 if (!size)
996 return 0;
997
998 for (block_id = start_block_id; block_id <= end_block_id; block_id++) {
999 mem = find_memory_block_by_id(block_id);
1000 if (!mem)
1001 continue;
1002
1003 ret = func(mem, arg);
1004 put_device(&mem->dev);
1005 if (ret)
1006 break;
1007 }
1008 return ret;
1009}
1010
1011struct for_each_memory_block_cb_data {
1012 walk_memory_blocks_func_t func;
1013 void *arg;
1014};
1015
1016static int for_each_memory_block_cb(struct device *dev, void *data)
1017{
1018 struct memory_block *mem = to_memory_block(dev);
1019 struct for_each_memory_block_cb_data *cb_data = data;
1020
1021 return cb_data->func(mem, cb_data->arg);
1022}
1023
1024/**
1025 * for_each_memory_block - walk through all present memory blocks
1026 *
1027 * @arg: argument passed to func
1028 * @func: callback for each memory block walked
1029 *
1030 * This function walks through all present memory blocks, calling func on
1031 * each memory block.
1032 *
1033 * In case func() returns an error, walking is aborted and the error is
1034 * returned.
1035 */
1036int for_each_memory_block(void *arg, walk_memory_blocks_func_t func)
1037{
1038 struct for_each_memory_block_cb_data cb_data = {
1039 .func = func,
1040 .arg = arg,
1041 };
1042
1043 return bus_for_each_dev(&memory_subsys, NULL, &cb_data,
1044 for_each_memory_block_cb);
1045}
1046
1047/*
1048 * This is an internal helper to unify allocation and initialization of
1049 * memory groups. Note that the passed memory group will be copied to a
1050 * dynamically allocated memory group. After this call, the passed
1051 * memory group should no longer be used.
1052 */
1053static int memory_group_register(struct memory_group group)
1054{
1055 struct memory_group *new_group;
1056 uint32_t mgid;
1057 int ret;
1058
1059 if (!node_possible(group.nid))
1060 return -EINVAL;
1061
1062 new_group = kzalloc(sizeof(group), GFP_KERNEL);
1063 if (!new_group)
1064 return -ENOMEM;
1065 *new_group = group;
1066 INIT_LIST_HEAD(&new_group->memory_blocks);
1067
1068 ret = xa_alloc(&memory_groups, &mgid, new_group, xa_limit_31b,
1069 GFP_KERNEL);
1070 if (ret) {
1071 kfree(new_group);
1072 return ret;
1073 } else if (group.is_dynamic) {
1074 xa_set_mark(&memory_groups, mgid, MEMORY_GROUP_MARK_DYNAMIC);
1075 }
1076 return mgid;
1077}
1078
1079/**
1080 * memory_group_register_static() - Register a static memory group.
1081 * @nid: The node id.
1082 * @max_pages: The maximum number of pages we'll have in this static memory
1083 * group.
1084 *
1085 * Register a new static memory group and return the memory group id.
1086 * All memory in the group belongs to a single unit, such as a DIMM. All
1087 * memory belonging to a static memory group is added in one go to be removed
1088 * in one go -- it's static.
1089 *
1090 * Returns an error if out of memory, if the node id is invalid, if no new
1091 * memory groups can be registered, or if max_pages is invalid (0). Otherwise,
1092 * returns the new memory group id.
1093 */
1094int memory_group_register_static(int nid, unsigned long max_pages)
1095{
1096 struct memory_group group = {
1097 .nid = nid,
1098 .s = {
1099 .max_pages = max_pages,
1100 },
1101 };
1102
1103 if (!max_pages)
1104 return -EINVAL;
1105 return memory_group_register(group);
1106}
1107EXPORT_SYMBOL_GPL(memory_group_register_static);
1108
1109/**
1110 * memory_group_register_dynamic() - Register a dynamic memory group.
1111 * @nid: The node id.
1112 * @unit_pages: Unit in pages in which is memory added/removed in this dynamic
1113 * memory group.
1114 *
1115 * Register a new dynamic memory group and return the memory group id.
1116 * Memory within a dynamic memory group is added/removed dynamically
1117 * in unit_pages.
1118 *
1119 * Returns an error if out of memory, if the node id is invalid, if no new
1120 * memory groups can be registered, or if unit_pages is invalid (0, not a
1121 * power of two, smaller than a single memory block). Otherwise, returns the
1122 * new memory group id.
1123 */
1124int memory_group_register_dynamic(int nid, unsigned long unit_pages)
1125{
1126 struct memory_group group = {
1127 .nid = nid,
1128 .is_dynamic = true,
1129 .d = {
1130 .unit_pages = unit_pages,
1131 },
1132 };
1133
1134 if (!unit_pages || !is_power_of_2(unit_pages) ||
1135 unit_pages < PHYS_PFN(memory_block_size_bytes()))
1136 return -EINVAL;
1137 return memory_group_register(group);
1138}
1139EXPORT_SYMBOL_GPL(memory_group_register_dynamic);
1140
1141/**
1142 * memory_group_unregister() - Unregister a memory group.
1143 * @mgid: the memory group id
1144 *
1145 * Unregister a memory group. If any memory block still belongs to this
1146 * memory group, unregistering will fail.
1147 *
1148 * Returns -EINVAL if the memory group id is invalid, returns -EBUSY if some
1149 * memory blocks still belong to this memory group and returns 0 if
1150 * unregistering succeeded.
1151 */
1152int memory_group_unregister(int mgid)
1153{
1154 struct memory_group *group;
1155
1156 if (mgid < 0)
1157 return -EINVAL;
1158
1159 group = xa_load(&memory_groups, mgid);
1160 if (!group)
1161 return -EINVAL;
1162 if (!list_empty(&group->memory_blocks))
1163 return -EBUSY;
1164 xa_erase(&memory_groups, mgid);
1165 kfree(group);
1166 return 0;
1167}
1168EXPORT_SYMBOL_GPL(memory_group_unregister);
1169
1170/*
1171 * This is an internal helper only to be used in core memory hotplug code to
1172 * lookup a memory group. We don't care about locking, as we don't expect a
1173 * memory group to get unregistered while adding memory to it -- because
1174 * the group and the memory is managed by the same driver.
1175 */
1176struct memory_group *memory_group_find_by_id(int mgid)
1177{
1178 return xa_load(&memory_groups, mgid);
1179}
1180
1181/*
1182 * This is an internal helper only to be used in core memory hotplug code to
1183 * walk all dynamic memory groups excluding a given memory group, either
1184 * belonging to a specific node, or belonging to any node.
1185 */
1186int walk_dynamic_memory_groups(int nid, walk_memory_groups_func_t func,
1187 struct memory_group *excluded, void *arg)
1188{
1189 struct memory_group *group;
1190 unsigned long index;
1191 int ret = 0;
1192
1193 xa_for_each_marked(&memory_groups, index, group,
1194 MEMORY_GROUP_MARK_DYNAMIC) {
1195 if (group == excluded)
1196 continue;
1197#ifdef CONFIG_NUMA
1198 if (nid != NUMA_NO_NODE && group->nid != nid)
1199 continue;
1200#endif /* CONFIG_NUMA */
1201 ret = func(group, arg);
1202 if (ret)
1203 break;
1204 }
1205 return ret;
1206}
1207
1208#if defined(CONFIG_MEMORY_FAILURE) && defined(CONFIG_MEMORY_HOTPLUG)
1209void memblk_nr_poison_inc(unsigned long pfn)
1210{
1211 const unsigned long block_id = pfn_to_block_id(pfn);
1212 struct memory_block *mem = find_memory_block_by_id(block_id);
1213
1214 if (mem)
1215 atomic_long_inc(&mem->nr_hwpoison);
1216}
1217
1218void memblk_nr_poison_sub(unsigned long pfn, long i)
1219{
1220 const unsigned long block_id = pfn_to_block_id(pfn);
1221 struct memory_block *mem = find_memory_block_by_id(block_id);
1222
1223 if (mem)
1224 atomic_long_sub(i, &mem->nr_hwpoison);
1225}
1226
1227static unsigned long memblk_nr_poison(struct memory_block *mem)
1228{
1229 return atomic_long_read(&mem->nr_hwpoison);
1230}
1231#endif
1/*
2 * Memory subsystem support
3 *
4 * Written by Matt Tolentino <matthew.e.tolentino@intel.com>
5 * Dave Hansen <haveblue@us.ibm.com>
6 *
7 * This file provides the necessary infrastructure to represent
8 * a SPARSEMEM-memory-model system's physical memory in /sysfs.
9 * All arch-independent code that assumes MEMORY_HOTPLUG requires
10 * SPARSEMEM should be contained here, or in mm/memory_hotplug.c.
11 */
12
13#include <linux/module.h>
14#include <linux/init.h>
15#include <linux/topology.h>
16#include <linux/capability.h>
17#include <linux/device.h>
18#include <linux/memory.h>
19#include <linux/memory_hotplug.h>
20#include <linux/mm.h>
21#include <linux/mutex.h>
22#include <linux/stat.h>
23#include <linux/slab.h>
24
25#include <linux/atomic.h>
26#include <asm/uaccess.h>
27
28static DEFINE_MUTEX(mem_sysfs_mutex);
29
30#define MEMORY_CLASS_NAME "memory"
31
32#define to_memory_block(dev) container_of(dev, struct memory_block, dev)
33
34static int sections_per_block;
35
36static inline int base_memory_block_id(int section_nr)
37{
38 return section_nr / sections_per_block;
39}
40
41static int memory_subsys_online(struct device *dev);
42static int memory_subsys_offline(struct device *dev);
43
44static struct bus_type memory_subsys = {
45 .name = MEMORY_CLASS_NAME,
46 .dev_name = MEMORY_CLASS_NAME,
47 .online = memory_subsys_online,
48 .offline = memory_subsys_offline,
49};
50
51static BLOCKING_NOTIFIER_HEAD(memory_chain);
52
53int register_memory_notifier(struct notifier_block *nb)
54{
55 return blocking_notifier_chain_register(&memory_chain, nb);
56}
57EXPORT_SYMBOL(register_memory_notifier);
58
59void unregister_memory_notifier(struct notifier_block *nb)
60{
61 blocking_notifier_chain_unregister(&memory_chain, nb);
62}
63EXPORT_SYMBOL(unregister_memory_notifier);
64
65static ATOMIC_NOTIFIER_HEAD(memory_isolate_chain);
66
67int register_memory_isolate_notifier(struct notifier_block *nb)
68{
69 return atomic_notifier_chain_register(&memory_isolate_chain, nb);
70}
71EXPORT_SYMBOL(register_memory_isolate_notifier);
72
73void unregister_memory_isolate_notifier(struct notifier_block *nb)
74{
75 atomic_notifier_chain_unregister(&memory_isolate_chain, nb);
76}
77EXPORT_SYMBOL(unregister_memory_isolate_notifier);
78
79static void memory_block_release(struct device *dev)
80{
81 struct memory_block *mem = to_memory_block(dev);
82
83 kfree(mem);
84}
85
86unsigned long __weak memory_block_size_bytes(void)
87{
88 return MIN_MEMORY_BLOCK_SIZE;
89}
90
91static unsigned long get_memory_block_size(void)
92{
93 unsigned long block_sz;
94
95 block_sz = memory_block_size_bytes();
96
97 /* Validate blk_sz is a power of 2 and not less than section size */
98 if ((block_sz & (block_sz - 1)) || (block_sz < MIN_MEMORY_BLOCK_SIZE)) {
99 WARN_ON(1);
100 block_sz = MIN_MEMORY_BLOCK_SIZE;
101 }
102
103 return block_sz;
104}
105
106/*
107 * use this as the physical section index that this memsection
108 * uses.
109 */
110
111static ssize_t show_mem_start_phys_index(struct device *dev,
112 struct device_attribute *attr, char *buf)
113{
114 struct memory_block *mem = to_memory_block(dev);
115 unsigned long phys_index;
116
117 phys_index = mem->start_section_nr / sections_per_block;
118 return sprintf(buf, "%08lx\n", phys_index);
119}
120
121/*
122 * Show whether the section of memory is likely to be hot-removable
123 */
124static ssize_t show_mem_removable(struct device *dev,
125 struct device_attribute *attr, char *buf)
126{
127 unsigned long i, pfn;
128 int ret = 1;
129 struct memory_block *mem = to_memory_block(dev);
130
131 for (i = 0; i < sections_per_block; i++) {
132 if (!present_section_nr(mem->start_section_nr + i))
133 continue;
134 pfn = section_nr_to_pfn(mem->start_section_nr + i);
135 ret &= is_mem_section_removable(pfn, PAGES_PER_SECTION);
136 }
137
138 return sprintf(buf, "%d\n", ret);
139}
140
141/*
142 * online, offline, going offline, etc.
143 */
144static ssize_t show_mem_state(struct device *dev,
145 struct device_attribute *attr, char *buf)
146{
147 struct memory_block *mem = to_memory_block(dev);
148 ssize_t len = 0;
149
150 /*
151 * We can probably put these states in a nice little array
152 * so that they're not open-coded
153 */
154 switch (mem->state) {
155 case MEM_ONLINE:
156 len = sprintf(buf, "online\n");
157 break;
158 case MEM_OFFLINE:
159 len = sprintf(buf, "offline\n");
160 break;
161 case MEM_GOING_OFFLINE:
162 len = sprintf(buf, "going-offline\n");
163 break;
164 default:
165 len = sprintf(buf, "ERROR-UNKNOWN-%ld\n",
166 mem->state);
167 WARN_ON(1);
168 break;
169 }
170
171 return len;
172}
173
174int memory_notify(unsigned long val, void *v)
175{
176 return blocking_notifier_call_chain(&memory_chain, val, v);
177}
178
179int memory_isolate_notify(unsigned long val, void *v)
180{
181 return atomic_notifier_call_chain(&memory_isolate_chain, val, v);
182}
183
184/*
185 * The probe routines leave the pages reserved, just as the bootmem code does.
186 * Make sure they're still that way.
187 */
188static bool pages_correctly_reserved(unsigned long start_pfn)
189{
190 int i, j;
191 struct page *page;
192 unsigned long pfn = start_pfn;
193
194 /*
195 * memmap between sections is not contiguous except with
196 * SPARSEMEM_VMEMMAP. We lookup the page once per section
197 * and assume memmap is contiguous within each section
198 */
199 for (i = 0; i < sections_per_block; i++, pfn += PAGES_PER_SECTION) {
200 if (WARN_ON_ONCE(!pfn_valid(pfn)))
201 return false;
202 page = pfn_to_page(pfn);
203
204 for (j = 0; j < PAGES_PER_SECTION; j++) {
205 if (PageReserved(page + j))
206 continue;
207
208 printk(KERN_WARNING "section number %ld page number %d "
209 "not reserved, was it already online?\n",
210 pfn_to_section_nr(pfn), j);
211
212 return false;
213 }
214 }
215
216 return true;
217}
218
219/*
220 * MEMORY_HOTPLUG depends on SPARSEMEM in mm/Kconfig, so it is
221 * OK to have direct references to sparsemem variables in here.
222 * Must already be protected by mem_hotplug_begin().
223 */
224static int
225memory_block_action(unsigned long phys_index, unsigned long action, int online_type)
226{
227 unsigned long start_pfn;
228 unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block;
229 struct page *first_page;
230 int ret;
231
232 start_pfn = section_nr_to_pfn(phys_index);
233 first_page = pfn_to_page(start_pfn);
234
235 switch (action) {
236 case MEM_ONLINE:
237 if (!pages_correctly_reserved(start_pfn))
238 return -EBUSY;
239
240 ret = online_pages(start_pfn, nr_pages, online_type);
241 break;
242 case MEM_OFFLINE:
243 ret = offline_pages(start_pfn, nr_pages);
244 break;
245 default:
246 WARN(1, KERN_WARNING "%s(%ld, %ld) unknown action: "
247 "%ld\n", __func__, phys_index, action, action);
248 ret = -EINVAL;
249 }
250
251 return ret;
252}
253
254int memory_block_change_state(struct memory_block *mem,
255 unsigned long to_state, unsigned long from_state_req)
256{
257 int ret = 0;
258
259 if (mem->state != from_state_req)
260 return -EINVAL;
261
262 if (to_state == MEM_OFFLINE)
263 mem->state = MEM_GOING_OFFLINE;
264
265 ret = memory_block_action(mem->start_section_nr, to_state,
266 mem->online_type);
267
268 mem->state = ret ? from_state_req : to_state;
269
270 return ret;
271}
272
273/* The device lock serializes operations on memory_subsys_[online|offline] */
274static int memory_subsys_online(struct device *dev)
275{
276 struct memory_block *mem = to_memory_block(dev);
277 int ret;
278
279 if (mem->state == MEM_ONLINE)
280 return 0;
281
282 /*
283 * If we are called from store_mem_state(), online_type will be
284 * set >= 0 Otherwise we were called from the device online
285 * attribute and need to set the online_type.
286 */
287 if (mem->online_type < 0)
288 mem->online_type = MMOP_ONLINE_KEEP;
289
290 /* Already under protection of mem_hotplug_begin() */
291 ret = memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE);
292
293 /* clear online_type */
294 mem->online_type = -1;
295
296 return ret;
297}
298
299static int memory_subsys_offline(struct device *dev)
300{
301 struct memory_block *mem = to_memory_block(dev);
302
303 if (mem->state == MEM_OFFLINE)
304 return 0;
305
306 /* Can't offline block with non-present sections */
307 if (mem->section_count != sections_per_block)
308 return -EINVAL;
309
310 return memory_block_change_state(mem, MEM_OFFLINE, MEM_ONLINE);
311}
312
313static ssize_t
314store_mem_state(struct device *dev,
315 struct device_attribute *attr, const char *buf, size_t count)
316{
317 struct memory_block *mem = to_memory_block(dev);
318 int ret, online_type;
319
320 ret = lock_device_hotplug_sysfs();
321 if (ret)
322 return ret;
323
324 if (sysfs_streq(buf, "online_kernel"))
325 online_type = MMOP_ONLINE_KERNEL;
326 else if (sysfs_streq(buf, "online_movable"))
327 online_type = MMOP_ONLINE_MOVABLE;
328 else if (sysfs_streq(buf, "online"))
329 online_type = MMOP_ONLINE_KEEP;
330 else if (sysfs_streq(buf, "offline"))
331 online_type = MMOP_OFFLINE;
332 else {
333 ret = -EINVAL;
334 goto err;
335 }
336
337 /*
338 * Memory hotplug needs to hold mem_hotplug_begin() for probe to find
339 * the correct memory block to online before doing device_online(dev),
340 * which will take dev->mutex. Take the lock early to prevent an
341 * inversion, memory_subsys_online() callbacks will be implemented by
342 * assuming it's already protected.
343 */
344 mem_hotplug_begin();
345
346 switch (online_type) {
347 case MMOP_ONLINE_KERNEL:
348 case MMOP_ONLINE_MOVABLE:
349 case MMOP_ONLINE_KEEP:
350 mem->online_type = online_type;
351 ret = device_online(&mem->dev);
352 break;
353 case MMOP_OFFLINE:
354 ret = device_offline(&mem->dev);
355 break;
356 default:
357 ret = -EINVAL; /* should never happen */
358 }
359
360 mem_hotplug_done();
361err:
362 unlock_device_hotplug();
363
364 if (ret)
365 return ret;
366 return count;
367}
368
369/*
370 * phys_device is a bad name for this. What I really want
371 * is a way to differentiate between memory ranges that
372 * are part of physical devices that constitute
373 * a complete removable unit or fru.
374 * i.e. do these ranges belong to the same physical device,
375 * s.t. if I offline all of these sections I can then
376 * remove the physical device?
377 */
378static ssize_t show_phys_device(struct device *dev,
379 struct device_attribute *attr, char *buf)
380{
381 struct memory_block *mem = to_memory_block(dev);
382 return sprintf(buf, "%d\n", mem->phys_device);
383}
384
385#ifdef CONFIG_MEMORY_HOTREMOVE
386static ssize_t show_valid_zones(struct device *dev,
387 struct device_attribute *attr, char *buf)
388{
389 struct memory_block *mem = to_memory_block(dev);
390 unsigned long start_pfn, end_pfn;
391 unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block;
392 struct page *first_page;
393 struct zone *zone;
394
395 start_pfn = section_nr_to_pfn(mem->start_section_nr);
396 end_pfn = start_pfn + nr_pages;
397 first_page = pfn_to_page(start_pfn);
398
399 /* The block contains more than one zone can not be offlined. */
400 if (!test_pages_in_a_zone(start_pfn, end_pfn))
401 return sprintf(buf, "none\n");
402
403 zone = page_zone(first_page);
404
405 if (zone_idx(zone) == ZONE_MOVABLE - 1) {
406 /*The mem block is the last memoryblock of this zone.*/
407 if (end_pfn == zone_end_pfn(zone))
408 return sprintf(buf, "%s %s\n",
409 zone->name, (zone + 1)->name);
410 }
411
412 if (zone_idx(zone) == ZONE_MOVABLE) {
413 /*The mem block is the first memoryblock of ZONE_MOVABLE.*/
414 if (start_pfn == zone->zone_start_pfn)
415 return sprintf(buf, "%s %s\n",
416 zone->name, (zone - 1)->name);
417 }
418
419 return sprintf(buf, "%s\n", zone->name);
420}
421static DEVICE_ATTR(valid_zones, 0444, show_valid_zones, NULL);
422#endif
423
424static DEVICE_ATTR(phys_index, 0444, show_mem_start_phys_index, NULL);
425static DEVICE_ATTR(state, 0644, show_mem_state, store_mem_state);
426static DEVICE_ATTR(phys_device, 0444, show_phys_device, NULL);
427static DEVICE_ATTR(removable, 0444, show_mem_removable, NULL);
428
429/*
430 * Block size attribute stuff
431 */
432static ssize_t
433print_block_size(struct device *dev, struct device_attribute *attr,
434 char *buf)
435{
436 return sprintf(buf, "%lx\n", get_memory_block_size());
437}
438
439static DEVICE_ATTR(block_size_bytes, 0444, print_block_size, NULL);
440
441/*
442 * Memory auto online policy.
443 */
444
445static ssize_t
446show_auto_online_blocks(struct device *dev, struct device_attribute *attr,
447 char *buf)
448{
449 if (memhp_auto_online)
450 return sprintf(buf, "online\n");
451 else
452 return sprintf(buf, "offline\n");
453}
454
455static ssize_t
456store_auto_online_blocks(struct device *dev, struct device_attribute *attr,
457 const char *buf, size_t count)
458{
459 if (sysfs_streq(buf, "online"))
460 memhp_auto_online = true;
461 else if (sysfs_streq(buf, "offline"))
462 memhp_auto_online = false;
463 else
464 return -EINVAL;
465
466 return count;
467}
468
469static DEVICE_ATTR(auto_online_blocks, 0644, show_auto_online_blocks,
470 store_auto_online_blocks);
471
472/*
473 * Some architectures will have custom drivers to do this, and
474 * will not need to do it from userspace. The fake hot-add code
475 * as well as ppc64 will do all of their discovery in userspace
476 * and will require this interface.
477 */
478#ifdef CONFIG_ARCH_MEMORY_PROBE
479static ssize_t
480memory_probe_store(struct device *dev, struct device_attribute *attr,
481 const char *buf, size_t count)
482{
483 u64 phys_addr;
484 int nid, ret;
485 unsigned long pages_per_block = PAGES_PER_SECTION * sections_per_block;
486
487 ret = kstrtoull(buf, 0, &phys_addr);
488 if (ret)
489 return ret;
490
491 if (phys_addr & ((pages_per_block << PAGE_SHIFT) - 1))
492 return -EINVAL;
493
494 nid = memory_add_physaddr_to_nid(phys_addr);
495 ret = add_memory(nid, phys_addr,
496 MIN_MEMORY_BLOCK_SIZE * sections_per_block);
497
498 if (ret)
499 goto out;
500
501 ret = count;
502out:
503 return ret;
504}
505
506static DEVICE_ATTR(probe, S_IWUSR, NULL, memory_probe_store);
507#endif
508
509#ifdef CONFIG_MEMORY_FAILURE
510/*
511 * Support for offlining pages of memory
512 */
513
514/* Soft offline a page */
515static ssize_t
516store_soft_offline_page(struct device *dev,
517 struct device_attribute *attr,
518 const char *buf, size_t count)
519{
520 int ret;
521 u64 pfn;
522 if (!capable(CAP_SYS_ADMIN))
523 return -EPERM;
524 if (kstrtoull(buf, 0, &pfn) < 0)
525 return -EINVAL;
526 pfn >>= PAGE_SHIFT;
527 if (!pfn_valid(pfn))
528 return -ENXIO;
529 ret = soft_offline_page(pfn_to_page(pfn), 0);
530 return ret == 0 ? count : ret;
531}
532
533/* Forcibly offline a page, including killing processes. */
534static ssize_t
535store_hard_offline_page(struct device *dev,
536 struct device_attribute *attr,
537 const char *buf, size_t count)
538{
539 int ret;
540 u64 pfn;
541 if (!capable(CAP_SYS_ADMIN))
542 return -EPERM;
543 if (kstrtoull(buf, 0, &pfn) < 0)
544 return -EINVAL;
545 pfn >>= PAGE_SHIFT;
546 ret = memory_failure(pfn, 0, 0);
547 return ret ? ret : count;
548}
549
550static DEVICE_ATTR(soft_offline_page, S_IWUSR, NULL, store_soft_offline_page);
551static DEVICE_ATTR(hard_offline_page, S_IWUSR, NULL, store_hard_offline_page);
552#endif
553
554/*
555 * Note that phys_device is optional. It is here to allow for
556 * differentiation between which *physical* devices each
557 * section belongs to...
558 */
559int __weak arch_get_memory_phys_device(unsigned long start_pfn)
560{
561 return 0;
562}
563
564/*
565 * A reference for the returned object is held and the reference for the
566 * hinted object is released.
567 */
568struct memory_block *find_memory_block_hinted(struct mem_section *section,
569 struct memory_block *hint)
570{
571 int block_id = base_memory_block_id(__section_nr(section));
572 struct device *hintdev = hint ? &hint->dev : NULL;
573 struct device *dev;
574
575 dev = subsys_find_device_by_id(&memory_subsys, block_id, hintdev);
576 if (hint)
577 put_device(&hint->dev);
578 if (!dev)
579 return NULL;
580 return to_memory_block(dev);
581}
582
583/*
584 * For now, we have a linear search to go find the appropriate
585 * memory_block corresponding to a particular phys_index. If
586 * this gets to be a real problem, we can always use a radix
587 * tree or something here.
588 *
589 * This could be made generic for all device subsystems.
590 */
591struct memory_block *find_memory_block(struct mem_section *section)
592{
593 return find_memory_block_hinted(section, NULL);
594}
595
596static struct attribute *memory_memblk_attrs[] = {
597 &dev_attr_phys_index.attr,
598 &dev_attr_state.attr,
599 &dev_attr_phys_device.attr,
600 &dev_attr_removable.attr,
601#ifdef CONFIG_MEMORY_HOTREMOVE
602 &dev_attr_valid_zones.attr,
603#endif
604 NULL
605};
606
607static struct attribute_group memory_memblk_attr_group = {
608 .attrs = memory_memblk_attrs,
609};
610
611static const struct attribute_group *memory_memblk_attr_groups[] = {
612 &memory_memblk_attr_group,
613 NULL,
614};
615
616/*
617 * register_memory - Setup a sysfs device for a memory block
618 */
619static
620int register_memory(struct memory_block *memory)
621{
622 memory->dev.bus = &memory_subsys;
623 memory->dev.id = memory->start_section_nr / sections_per_block;
624 memory->dev.release = memory_block_release;
625 memory->dev.groups = memory_memblk_attr_groups;
626 memory->dev.offline = memory->state == MEM_OFFLINE;
627
628 return device_register(&memory->dev);
629}
630
631static int init_memory_block(struct memory_block **memory,
632 struct mem_section *section, unsigned long state)
633{
634 struct memory_block *mem;
635 unsigned long start_pfn;
636 int scn_nr;
637 int ret = 0;
638
639 mem = kzalloc(sizeof(*mem), GFP_KERNEL);
640 if (!mem)
641 return -ENOMEM;
642
643 scn_nr = __section_nr(section);
644 mem->start_section_nr =
645 base_memory_block_id(scn_nr) * sections_per_block;
646 mem->end_section_nr = mem->start_section_nr + sections_per_block - 1;
647 mem->state = state;
648 start_pfn = section_nr_to_pfn(mem->start_section_nr);
649 mem->phys_device = arch_get_memory_phys_device(start_pfn);
650
651 ret = register_memory(mem);
652
653 *memory = mem;
654 return ret;
655}
656
657static int add_memory_block(int base_section_nr)
658{
659 struct memory_block *mem;
660 int i, ret, section_count = 0, section_nr;
661
662 for (i = base_section_nr;
663 (i < base_section_nr + sections_per_block) && i < NR_MEM_SECTIONS;
664 i++) {
665 if (!present_section_nr(i))
666 continue;
667 if (section_count == 0)
668 section_nr = i;
669 section_count++;
670 }
671
672 if (section_count == 0)
673 return 0;
674 ret = init_memory_block(&mem, __nr_to_section(section_nr), MEM_ONLINE);
675 if (ret)
676 return ret;
677 mem->section_count = section_count;
678 return 0;
679}
680
681static bool is_zone_device_section(struct mem_section *ms)
682{
683 struct page *page;
684
685 page = sparse_decode_mem_map(ms->section_mem_map, __section_nr(ms));
686 return is_zone_device_page(page);
687}
688
689/*
690 * need an interface for the VM to add new memory regions,
691 * but without onlining it.
692 */
693int register_new_memory(int nid, struct mem_section *section)
694{
695 int ret = 0;
696 struct memory_block *mem;
697
698 if (is_zone_device_section(section))
699 return 0;
700
701 mutex_lock(&mem_sysfs_mutex);
702
703 mem = find_memory_block(section);
704 if (mem) {
705 mem->section_count++;
706 put_device(&mem->dev);
707 } else {
708 ret = init_memory_block(&mem, section, MEM_OFFLINE);
709 if (ret)
710 goto out;
711 mem->section_count++;
712 }
713
714 if (mem->section_count == sections_per_block)
715 ret = register_mem_sect_under_node(mem, nid);
716out:
717 mutex_unlock(&mem_sysfs_mutex);
718 return ret;
719}
720
721#ifdef CONFIG_MEMORY_HOTREMOVE
722static void
723unregister_memory(struct memory_block *memory)
724{
725 BUG_ON(memory->dev.bus != &memory_subsys);
726
727 /* drop the ref. we got in remove_memory_block() */
728 put_device(&memory->dev);
729 device_unregister(&memory->dev);
730}
731
732static int remove_memory_section(unsigned long node_id,
733 struct mem_section *section, int phys_device)
734{
735 struct memory_block *mem;
736
737 if (is_zone_device_section(section))
738 return 0;
739
740 mutex_lock(&mem_sysfs_mutex);
741 mem = find_memory_block(section);
742 unregister_mem_sect_under_nodes(mem, __section_nr(section));
743
744 mem->section_count--;
745 if (mem->section_count == 0)
746 unregister_memory(mem);
747 else
748 put_device(&mem->dev);
749
750 mutex_unlock(&mem_sysfs_mutex);
751 return 0;
752}
753
754int unregister_memory_section(struct mem_section *section)
755{
756 if (!present_section(section))
757 return -EINVAL;
758
759 return remove_memory_section(0, section, 0);
760}
761#endif /* CONFIG_MEMORY_HOTREMOVE */
762
763/* return true if the memory block is offlined, otherwise, return false */
764bool is_memblock_offlined(struct memory_block *mem)
765{
766 return mem->state == MEM_OFFLINE;
767}
768
769static struct attribute *memory_root_attrs[] = {
770#ifdef CONFIG_ARCH_MEMORY_PROBE
771 &dev_attr_probe.attr,
772#endif
773
774#ifdef CONFIG_MEMORY_FAILURE
775 &dev_attr_soft_offline_page.attr,
776 &dev_attr_hard_offline_page.attr,
777#endif
778
779 &dev_attr_block_size_bytes.attr,
780 &dev_attr_auto_online_blocks.attr,
781 NULL
782};
783
784static struct attribute_group memory_root_attr_group = {
785 .attrs = memory_root_attrs,
786};
787
788static const struct attribute_group *memory_root_attr_groups[] = {
789 &memory_root_attr_group,
790 NULL,
791};
792
793/*
794 * Initialize the sysfs support for memory devices...
795 */
796int __init memory_dev_init(void)
797{
798 unsigned int i;
799 int ret;
800 int err;
801 unsigned long block_sz;
802
803 ret = subsys_system_register(&memory_subsys, memory_root_attr_groups);
804 if (ret)
805 goto out;
806
807 block_sz = get_memory_block_size();
808 sections_per_block = block_sz / MIN_MEMORY_BLOCK_SIZE;
809
810 /*
811 * Create entries for memory sections that were found
812 * during boot and have been initialized
813 */
814 mutex_lock(&mem_sysfs_mutex);
815 for (i = 0; i < NR_MEM_SECTIONS; i += sections_per_block) {
816 err = add_memory_block(i);
817 if (!ret)
818 ret = err;
819 }
820 mutex_unlock(&mem_sysfs_mutex);
821
822out:
823 if (ret)
824 printk(KERN_ERR "%s() failed: %d\n", __func__, ret);
825 return ret;
826}