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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/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}
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 unsigned long base_memory_block_id(unsigned long section_nr)
38{
39 return section_nr / sections_per_block;
40}
41
42static inline unsigned long pfn_to_block_id(unsigned long pfn)
43{
44 return base_memory_block_id(pfn_to_section_nr(pfn));
45}
46
47static inline unsigned long phys_to_block_id(unsigned long phys)
48{
49 return pfn_to_block_id(PFN_DOWN(phys));
50}
51
52static int memory_subsys_online(struct device *dev);
53static int memory_subsys_offline(struct device *dev);
54
55static struct bus_type memory_subsys = {
56 .name = MEMORY_CLASS_NAME,
57 .dev_name = MEMORY_CLASS_NAME,
58 .online = memory_subsys_online,
59 .offline = memory_subsys_offline,
60};
61
62static BLOCKING_NOTIFIER_HEAD(memory_chain);
63
64int register_memory_notifier(struct notifier_block *nb)
65{
66 return blocking_notifier_chain_register(&memory_chain, nb);
67}
68EXPORT_SYMBOL(register_memory_notifier);
69
70void unregister_memory_notifier(struct notifier_block *nb)
71{
72 blocking_notifier_chain_unregister(&memory_chain, nb);
73}
74EXPORT_SYMBOL(unregister_memory_notifier);
75
76static ATOMIC_NOTIFIER_HEAD(memory_isolate_chain);
77
78int register_memory_isolate_notifier(struct notifier_block *nb)
79{
80 return atomic_notifier_chain_register(&memory_isolate_chain, nb);
81}
82EXPORT_SYMBOL(register_memory_isolate_notifier);
83
84void unregister_memory_isolate_notifier(struct notifier_block *nb)
85{
86 atomic_notifier_chain_unregister(&memory_isolate_chain, nb);
87}
88EXPORT_SYMBOL(unregister_memory_isolate_notifier);
89
90static void memory_block_release(struct device *dev)
91{
92 struct memory_block *mem = to_memory_block(dev);
93
94 kfree(mem);
95}
96
97unsigned long __weak memory_block_size_bytes(void)
98{
99 return MIN_MEMORY_BLOCK_SIZE;
100}
101EXPORT_SYMBOL_GPL(memory_block_size_bytes);
102
103/*
104 * Show the first physical section index (number) of this memory block.
105 */
106static ssize_t phys_index_show(struct device *dev,
107 struct device_attribute *attr, char *buf)
108{
109 struct memory_block *mem = to_memory_block(dev);
110 unsigned long phys_index;
111
112 phys_index = mem->start_section_nr / sections_per_block;
113 return sprintf(buf, "%08lx\n", phys_index);
114}
115
116/*
117 * Show whether the memory block is likely to be offlineable (or is already
118 * offline). Once offline, the memory block could be removed. The return
119 * value does, however, not indicate that there is a way to remove the
120 * memory block.
121 */
122static ssize_t removable_show(struct device *dev, struct device_attribute *attr,
123 char *buf)
124{
125 struct memory_block *mem = to_memory_block(dev);
126 unsigned long pfn;
127 int ret = 1, i;
128
129 if (mem->state != MEM_ONLINE)
130 goto out;
131
132 for (i = 0; i < sections_per_block; i++) {
133 if (!present_section_nr(mem->start_section_nr + i))
134 continue;
135 pfn = section_nr_to_pfn(mem->start_section_nr + i);
136 ret &= is_mem_section_removable(pfn, PAGES_PER_SECTION);
137 }
138
139out:
140 return sprintf(buf, "%d\n", ret);
141}
142
143/*
144 * online, offline, going offline, etc.
145 */
146static ssize_t state_show(struct device *dev, struct device_attribute *attr,
147 char *buf)
148{
149 struct memory_block *mem = to_memory_block(dev);
150 ssize_t len = 0;
151
152 /*
153 * We can probably put these states in a nice little array
154 * so that they're not open-coded
155 */
156 switch (mem->state) {
157 case MEM_ONLINE:
158 len = sprintf(buf, "online\n");
159 break;
160 case MEM_OFFLINE:
161 len = sprintf(buf, "offline\n");
162 break;
163 case MEM_GOING_OFFLINE:
164 len = sprintf(buf, "going-offline\n");
165 break;
166 default:
167 len = sprintf(buf, "ERROR-UNKNOWN-%ld\n",
168 mem->state);
169 WARN_ON(1);
170 break;
171 }
172
173 return len;
174}
175
176int memory_notify(unsigned long val, void *v)
177{
178 return blocking_notifier_call_chain(&memory_chain, val, v);
179}
180
181int memory_isolate_notify(unsigned long val, void *v)
182{
183 return atomic_notifier_call_chain(&memory_isolate_chain, val, v);
184}
185
186/*
187 * The probe routines leave the pages uninitialized, just as the bootmem code
188 * does. Make sure we do not access them, but instead use only information from
189 * within sections.
190 */
191static bool pages_correctly_probed(unsigned long start_pfn)
192{
193 unsigned long section_nr = pfn_to_section_nr(start_pfn);
194 unsigned long section_nr_end = section_nr + sections_per_block;
195 unsigned long pfn = start_pfn;
196
197 /*
198 * memmap between sections is not contiguous except with
199 * SPARSEMEM_VMEMMAP. We lookup the page once per section
200 * and assume memmap is contiguous within each section
201 */
202 for (; section_nr < section_nr_end; section_nr++) {
203 if (WARN_ON_ONCE(!pfn_valid(pfn)))
204 return false;
205
206 if (!present_section_nr(section_nr)) {
207 pr_warn("section %ld pfn[%lx, %lx) not present\n",
208 section_nr, pfn, pfn + PAGES_PER_SECTION);
209 return false;
210 } else if (!valid_section_nr(section_nr)) {
211 pr_warn("section %ld pfn[%lx, %lx) no valid memmap\n",
212 section_nr, pfn, pfn + PAGES_PER_SECTION);
213 return false;
214 } else if (online_section_nr(section_nr)) {
215 pr_warn("section %ld pfn[%lx, %lx) is already online\n",
216 section_nr, pfn, pfn + PAGES_PER_SECTION);
217 return false;
218 }
219 pfn += PAGES_PER_SECTION;
220 }
221
222 return true;
223}
224
225/*
226 * MEMORY_HOTPLUG depends on SPARSEMEM in mm/Kconfig, so it is
227 * OK to have direct references to sparsemem variables in here.
228 */
229static int
230memory_block_action(unsigned long start_section_nr, unsigned long action,
231 int online_type)
232{
233 unsigned long start_pfn;
234 unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block;
235 int ret;
236
237 start_pfn = section_nr_to_pfn(start_section_nr);
238
239 switch (action) {
240 case MEM_ONLINE:
241 if (!pages_correctly_probed(start_pfn))
242 return -EBUSY;
243
244 ret = online_pages(start_pfn, nr_pages, online_type);
245 break;
246 case MEM_OFFLINE:
247 ret = offline_pages(start_pfn, nr_pages);
248 break;
249 default:
250 WARN(1, KERN_WARNING "%s(%ld, %ld) unknown action: "
251 "%ld\n", __func__, start_section_nr, action, action);
252 ret = -EINVAL;
253 }
254
255 return ret;
256}
257
258static int memory_block_change_state(struct memory_block *mem,
259 unsigned long to_state, unsigned long from_state_req)
260{
261 int ret = 0;
262
263 if (mem->state != from_state_req)
264 return -EINVAL;
265
266 if (to_state == MEM_OFFLINE)
267 mem->state = MEM_GOING_OFFLINE;
268
269 ret = memory_block_action(mem->start_section_nr, to_state,
270 mem->online_type);
271
272 mem->state = ret ? from_state_req : to_state;
273
274 return ret;
275}
276
277/* The device lock serializes operations on memory_subsys_[online|offline] */
278static int memory_subsys_online(struct device *dev)
279{
280 struct memory_block *mem = to_memory_block(dev);
281 int ret;
282
283 if (mem->state == MEM_ONLINE)
284 return 0;
285
286 /*
287 * If we are called from state_store(), online_type will be
288 * set >= 0 Otherwise we were called from the device online
289 * attribute and need to set the online_type.
290 */
291 if (mem->online_type < 0)
292 mem->online_type = MMOP_ONLINE_KEEP;
293
294 ret = memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE);
295
296 /* clear online_type */
297 mem->online_type = -1;
298
299 return ret;
300}
301
302static int memory_subsys_offline(struct device *dev)
303{
304 struct memory_block *mem = to_memory_block(dev);
305
306 if (mem->state == MEM_OFFLINE)
307 return 0;
308
309 /* Can't offline block with non-present sections */
310 if (mem->section_count != sections_per_block)
311 return -EINVAL;
312
313 return memory_block_change_state(mem, MEM_OFFLINE, MEM_ONLINE);
314}
315
316static ssize_t state_store(struct device *dev, struct device_attribute *attr,
317 const char *buf, size_t count)
318{
319 struct memory_block *mem = to_memory_block(dev);
320 int ret, online_type;
321
322 ret = lock_device_hotplug_sysfs();
323 if (ret)
324 return ret;
325
326 if (sysfs_streq(buf, "online_kernel"))
327 online_type = MMOP_ONLINE_KERNEL;
328 else if (sysfs_streq(buf, "online_movable"))
329 online_type = MMOP_ONLINE_MOVABLE;
330 else if (sysfs_streq(buf, "online"))
331 online_type = MMOP_ONLINE_KEEP;
332 else if (sysfs_streq(buf, "offline"))
333 online_type = MMOP_OFFLINE;
334 else {
335 ret = -EINVAL;
336 goto err;
337 }
338
339 switch (online_type) {
340 case MMOP_ONLINE_KERNEL:
341 case MMOP_ONLINE_MOVABLE:
342 case MMOP_ONLINE_KEEP:
343 /* mem->online_type is protected by device_hotplug_lock */
344 mem->online_type = online_type;
345 ret = device_online(&mem->dev);
346 break;
347 case MMOP_OFFLINE:
348 ret = device_offline(&mem->dev);
349 break;
350 default:
351 ret = -EINVAL; /* should never happen */
352 }
353
354err:
355 unlock_device_hotplug();
356
357 if (ret < 0)
358 return ret;
359 if (ret)
360 return -EINVAL;
361
362 return count;
363}
364
365/*
366 * phys_device is a bad name for this. What I really want
367 * is a way to differentiate between memory ranges that
368 * are part of physical devices that constitute
369 * a complete removable unit or fru.
370 * i.e. do these ranges belong to the same physical device,
371 * s.t. if I offline all of these sections I can then
372 * remove the physical device?
373 */
374static ssize_t phys_device_show(struct device *dev,
375 struct device_attribute *attr, char *buf)
376{
377 struct memory_block *mem = to_memory_block(dev);
378 return sprintf(buf, "%d\n", mem->phys_device);
379}
380
381#ifdef CONFIG_MEMORY_HOTREMOVE
382static void print_allowed_zone(char *buf, int nid, unsigned long start_pfn,
383 unsigned long nr_pages, int online_type,
384 struct zone *default_zone)
385{
386 struct zone *zone;
387
388 zone = zone_for_pfn_range(online_type, nid, start_pfn, nr_pages);
389 if (zone != default_zone) {
390 strcat(buf, " ");
391 strcat(buf, zone->name);
392 }
393}
394
395static ssize_t valid_zones_show(struct device *dev,
396 struct device_attribute *attr, char *buf)
397{
398 struct memory_block *mem = to_memory_block(dev);
399 unsigned long start_pfn = section_nr_to_pfn(mem->start_section_nr);
400 unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block;
401 unsigned long valid_start_pfn, valid_end_pfn;
402 struct zone *default_zone;
403 int nid;
404
405 /*
406 * Check the existing zone. Make sure that we do that only on the
407 * online nodes otherwise the page_zone is not reliable
408 */
409 if (mem->state == MEM_ONLINE) {
410 /*
411 * The block contains more than one zone can not be offlined.
412 * This can happen e.g. for ZONE_DMA and ZONE_DMA32
413 */
414 if (!test_pages_in_a_zone(start_pfn, start_pfn + nr_pages,
415 &valid_start_pfn, &valid_end_pfn))
416 return sprintf(buf, "none\n");
417 start_pfn = valid_start_pfn;
418 strcat(buf, page_zone(pfn_to_page(start_pfn))->name);
419 goto out;
420 }
421
422 nid = mem->nid;
423 default_zone = zone_for_pfn_range(MMOP_ONLINE_KEEP, nid, start_pfn, nr_pages);
424 strcat(buf, default_zone->name);
425
426 print_allowed_zone(buf, nid, start_pfn, nr_pages, MMOP_ONLINE_KERNEL,
427 default_zone);
428 print_allowed_zone(buf, nid, start_pfn, nr_pages, MMOP_ONLINE_MOVABLE,
429 default_zone);
430out:
431 strcat(buf, "\n");
432
433 return strlen(buf);
434}
435static DEVICE_ATTR_RO(valid_zones);
436#endif
437
438static DEVICE_ATTR_RO(phys_index);
439static DEVICE_ATTR_RW(state);
440static DEVICE_ATTR_RO(phys_device);
441static DEVICE_ATTR_RO(removable);
442
443/*
444 * Show the memory block size (shared by all memory blocks).
445 */
446static ssize_t block_size_bytes_show(struct device *dev,
447 struct device_attribute *attr, char *buf)
448{
449 return sprintf(buf, "%lx\n", memory_block_size_bytes());
450}
451
452static DEVICE_ATTR_RO(block_size_bytes);
453
454/*
455 * Memory auto online policy.
456 */
457
458static ssize_t auto_online_blocks_show(struct device *dev,
459 struct device_attribute *attr, char *buf)
460{
461 if (memhp_auto_online)
462 return sprintf(buf, "online\n");
463 else
464 return sprintf(buf, "offline\n");
465}
466
467static ssize_t auto_online_blocks_store(struct device *dev,
468 struct device_attribute *attr,
469 const char *buf, size_t count)
470{
471 if (sysfs_streq(buf, "online"))
472 memhp_auto_online = true;
473 else if (sysfs_streq(buf, "offline"))
474 memhp_auto_online = false;
475 else
476 return -EINVAL;
477
478 return count;
479}
480
481static DEVICE_ATTR_RW(auto_online_blocks);
482
483/*
484 * Some architectures will have custom drivers to do this, and
485 * will not need to do it from userspace. The fake hot-add code
486 * as well as ppc64 will do all of their discovery in userspace
487 * and will require this interface.
488 */
489#ifdef CONFIG_ARCH_MEMORY_PROBE
490static ssize_t probe_store(struct device *dev, struct device_attribute *attr,
491 const char *buf, size_t count)
492{
493 u64 phys_addr;
494 int nid, ret;
495 unsigned long pages_per_block = PAGES_PER_SECTION * sections_per_block;
496
497 ret = kstrtoull(buf, 0, &phys_addr);
498 if (ret)
499 return ret;
500
501 if (phys_addr & ((pages_per_block << PAGE_SHIFT) - 1))
502 return -EINVAL;
503
504 ret = lock_device_hotplug_sysfs();
505 if (ret)
506 return ret;
507
508 nid = memory_add_physaddr_to_nid(phys_addr);
509 ret = __add_memory(nid, phys_addr,
510 MIN_MEMORY_BLOCK_SIZE * sections_per_block);
511
512 if (ret)
513 goto out;
514
515 ret = count;
516out:
517 unlock_device_hotplug();
518 return ret;
519}
520
521static DEVICE_ATTR_WO(probe);
522#endif
523
524#ifdef CONFIG_MEMORY_FAILURE
525/*
526 * Support for offlining pages of memory
527 */
528
529/* Soft offline a page */
530static ssize_t soft_offline_page_store(struct device *dev,
531 struct device_attribute *attr,
532 const char *buf, size_t count)
533{
534 int ret;
535 u64 pfn;
536 if (!capable(CAP_SYS_ADMIN))
537 return -EPERM;
538 if (kstrtoull(buf, 0, &pfn) < 0)
539 return -EINVAL;
540 pfn >>= PAGE_SHIFT;
541 if (!pfn_valid(pfn))
542 return -ENXIO;
543 /* Only online pages can be soft-offlined (esp., not ZONE_DEVICE). */
544 if (!pfn_to_online_page(pfn))
545 return -EIO;
546 ret = soft_offline_page(pfn_to_page(pfn), 0);
547 return ret == 0 ? count : ret;
548}
549
550/* Forcibly offline a page, including killing processes. */
551static ssize_t hard_offline_page_store(struct device *dev,
552 struct device_attribute *attr,
553 const char *buf, size_t count)
554{
555 int ret;
556 u64 pfn;
557 if (!capable(CAP_SYS_ADMIN))
558 return -EPERM;
559 if (kstrtoull(buf, 0, &pfn) < 0)
560 return -EINVAL;
561 pfn >>= PAGE_SHIFT;
562 ret = memory_failure(pfn, 0);
563 return ret ? ret : count;
564}
565
566static DEVICE_ATTR_WO(soft_offline_page);
567static DEVICE_ATTR_WO(hard_offline_page);
568#endif
569
570/*
571 * Note that phys_device is optional. It is here to allow for
572 * differentiation between which *physical* devices each
573 * section belongs to...
574 */
575int __weak arch_get_memory_phys_device(unsigned long start_pfn)
576{
577 return 0;
578}
579
580/* A reference for the returned memory block device is acquired. */
581static struct memory_block *find_memory_block_by_id(unsigned long block_id)
582{
583 struct device *dev;
584
585 dev = subsys_find_device_by_id(&memory_subsys, block_id, NULL);
586 return dev ? to_memory_block(dev) : NULL;
587}
588
589/*
590 * For now, we have a linear search to go find the appropriate
591 * memory_block corresponding to a particular phys_index. If
592 * this gets to be a real problem, we can always use a radix
593 * tree or something here.
594 *
595 * This could be made generic for all device subsystems.
596 */
597struct memory_block *find_memory_block(struct mem_section *section)
598{
599 unsigned long block_id = base_memory_block_id(__section_nr(section));
600
601 return find_memory_block_by_id(block_id);
602}
603
604static struct attribute *memory_memblk_attrs[] = {
605 &dev_attr_phys_index.attr,
606 &dev_attr_state.attr,
607 &dev_attr_phys_device.attr,
608 &dev_attr_removable.attr,
609#ifdef CONFIG_MEMORY_HOTREMOVE
610 &dev_attr_valid_zones.attr,
611#endif
612 NULL
613};
614
615static struct attribute_group memory_memblk_attr_group = {
616 .attrs = memory_memblk_attrs,
617};
618
619static const struct attribute_group *memory_memblk_attr_groups[] = {
620 &memory_memblk_attr_group,
621 NULL,
622};
623
624/*
625 * register_memory - Setup a sysfs device for a memory block
626 */
627static
628int register_memory(struct memory_block *memory)
629{
630 int ret;
631
632 memory->dev.bus = &memory_subsys;
633 memory->dev.id = memory->start_section_nr / sections_per_block;
634 memory->dev.release = memory_block_release;
635 memory->dev.groups = memory_memblk_attr_groups;
636 memory->dev.offline = memory->state == MEM_OFFLINE;
637
638 ret = device_register(&memory->dev);
639 if (ret)
640 put_device(&memory->dev);
641
642 return ret;
643}
644
645static int init_memory_block(struct memory_block **memory,
646 unsigned long block_id, unsigned long state)
647{
648 struct memory_block *mem;
649 unsigned long start_pfn;
650 int ret = 0;
651
652 mem = find_memory_block_by_id(block_id);
653 if (mem) {
654 put_device(&mem->dev);
655 return -EEXIST;
656 }
657 mem = kzalloc(sizeof(*mem), GFP_KERNEL);
658 if (!mem)
659 return -ENOMEM;
660
661 mem->start_section_nr = block_id * sections_per_block;
662 mem->state = state;
663 start_pfn = section_nr_to_pfn(mem->start_section_nr);
664 mem->phys_device = arch_get_memory_phys_device(start_pfn);
665 mem->nid = NUMA_NO_NODE;
666
667 ret = register_memory(mem);
668
669 *memory = mem;
670 return ret;
671}
672
673static int add_memory_block(unsigned long base_section_nr)
674{
675 int ret, section_count = 0;
676 struct memory_block *mem;
677 unsigned long nr;
678
679 for (nr = base_section_nr; nr < base_section_nr + sections_per_block;
680 nr++)
681 if (present_section_nr(nr))
682 section_count++;
683
684 if (section_count == 0)
685 return 0;
686 ret = init_memory_block(&mem, base_memory_block_id(base_section_nr),
687 MEM_ONLINE);
688 if (ret)
689 return ret;
690 mem->section_count = section_count;
691 return 0;
692}
693
694static void unregister_memory(struct memory_block *memory)
695{
696 if (WARN_ON_ONCE(memory->dev.bus != &memory_subsys))
697 return;
698
699 /* drop the ref. we got via find_memory_block() */
700 put_device(&memory->dev);
701 device_unregister(&memory->dev);
702}
703
704/*
705 * Create memory block devices for the given memory area. Start and size
706 * have to be aligned to memory block granularity. Memory block devices
707 * will be initialized as offline.
708 */
709int create_memory_block_devices(unsigned long start, unsigned long size)
710{
711 const unsigned long start_block_id = pfn_to_block_id(PFN_DOWN(start));
712 unsigned long end_block_id = pfn_to_block_id(PFN_DOWN(start + size));
713 struct memory_block *mem;
714 unsigned long block_id;
715 int ret = 0;
716
717 if (WARN_ON_ONCE(!IS_ALIGNED(start, memory_block_size_bytes()) ||
718 !IS_ALIGNED(size, memory_block_size_bytes())))
719 return -EINVAL;
720
721 mutex_lock(&mem_sysfs_mutex);
722 for (block_id = start_block_id; block_id != end_block_id; block_id++) {
723 ret = init_memory_block(&mem, block_id, MEM_OFFLINE);
724 if (ret)
725 break;
726 mem->section_count = sections_per_block;
727 }
728 if (ret) {
729 end_block_id = block_id;
730 for (block_id = start_block_id; block_id != end_block_id;
731 block_id++) {
732 mem = find_memory_block_by_id(block_id);
733 mem->section_count = 0;
734 unregister_memory(mem);
735 }
736 }
737 mutex_unlock(&mem_sysfs_mutex);
738 return ret;
739}
740
741/*
742 * Remove memory block devices for the given memory area. Start and size
743 * have to be aligned to memory block granularity. Memory block devices
744 * have to be offline.
745 */
746void remove_memory_block_devices(unsigned long start, unsigned long size)
747{
748 const unsigned long start_block_id = pfn_to_block_id(PFN_DOWN(start));
749 const unsigned long end_block_id = pfn_to_block_id(PFN_DOWN(start + size));
750 struct memory_block *mem;
751 unsigned long block_id;
752
753 if (WARN_ON_ONCE(!IS_ALIGNED(start, memory_block_size_bytes()) ||
754 !IS_ALIGNED(size, memory_block_size_bytes())))
755 return;
756
757 mutex_lock(&mem_sysfs_mutex);
758 for (block_id = start_block_id; block_id != end_block_id; block_id++) {
759 mem = find_memory_block_by_id(block_id);
760 if (WARN_ON_ONCE(!mem))
761 continue;
762 mem->section_count = 0;
763 unregister_memory_block_under_nodes(mem);
764 unregister_memory(mem);
765 }
766 mutex_unlock(&mem_sysfs_mutex);
767}
768
769/* return true if the memory block is offlined, otherwise, return false */
770bool is_memblock_offlined(struct memory_block *mem)
771{
772 return mem->state == MEM_OFFLINE;
773}
774
775static struct attribute *memory_root_attrs[] = {
776#ifdef CONFIG_ARCH_MEMORY_PROBE
777 &dev_attr_probe.attr,
778#endif
779
780#ifdef CONFIG_MEMORY_FAILURE
781 &dev_attr_soft_offline_page.attr,
782 &dev_attr_hard_offline_page.attr,
783#endif
784
785 &dev_attr_block_size_bytes.attr,
786 &dev_attr_auto_online_blocks.attr,
787 NULL
788};
789
790static struct attribute_group memory_root_attr_group = {
791 .attrs = memory_root_attrs,
792};
793
794static const struct attribute_group *memory_root_attr_groups[] = {
795 &memory_root_attr_group,
796 NULL,
797};
798
799/*
800 * Initialize the sysfs support for memory devices...
801 */
802void __init memory_dev_init(void)
803{
804 int ret;
805 int err;
806 unsigned long block_sz, nr;
807
808 /* Validate the configured memory block size */
809 block_sz = memory_block_size_bytes();
810 if (!is_power_of_2(block_sz) || block_sz < MIN_MEMORY_BLOCK_SIZE)
811 panic("Memory block size not suitable: 0x%lx\n", block_sz);
812 sections_per_block = block_sz / MIN_MEMORY_BLOCK_SIZE;
813
814 ret = subsys_system_register(&memory_subsys, memory_root_attr_groups);
815 if (ret)
816 goto out;
817
818 /*
819 * Create entries for memory sections that were found
820 * during boot and have been initialized
821 */
822 mutex_lock(&mem_sysfs_mutex);
823 for (nr = 0; nr <= __highest_present_section_nr;
824 nr += sections_per_block) {
825 err = add_memory_block(nr);
826 if (!ret)
827 ret = err;
828 }
829 mutex_unlock(&mem_sysfs_mutex);
830
831out:
832 if (ret)
833 panic("%s() failed: %d\n", __func__, ret);
834}
835
836/**
837 * walk_memory_blocks - walk through all present memory blocks overlapped
838 * by the range [start, start + size)
839 *
840 * @start: start address of the memory range
841 * @size: size of the memory range
842 * @arg: argument passed to func
843 * @func: callback for each memory section walked
844 *
845 * This function walks through all present memory blocks overlapped by the
846 * range [start, start + size), calling func on each memory block.
847 *
848 * In case func() returns an error, walking is aborted and the error is
849 * returned.
850 */
851int walk_memory_blocks(unsigned long start, unsigned long size,
852 void *arg, walk_memory_blocks_func_t func)
853{
854 const unsigned long start_block_id = phys_to_block_id(start);
855 const unsigned long end_block_id = phys_to_block_id(start + size - 1);
856 struct memory_block *mem;
857 unsigned long block_id;
858 int ret = 0;
859
860 if (!size)
861 return 0;
862
863 for (block_id = start_block_id; block_id <= end_block_id; block_id++) {
864 mem = find_memory_block_by_id(block_id);
865 if (!mem)
866 continue;
867
868 ret = func(mem, arg);
869 put_device(&mem->dev);
870 if (ret)
871 break;
872 }
873 return ret;
874}
875
876struct for_each_memory_block_cb_data {
877 walk_memory_blocks_func_t func;
878 void *arg;
879};
880
881static int for_each_memory_block_cb(struct device *dev, void *data)
882{
883 struct memory_block *mem = to_memory_block(dev);
884 struct for_each_memory_block_cb_data *cb_data = data;
885
886 return cb_data->func(mem, cb_data->arg);
887}
888
889/**
890 * for_each_memory_block - walk through all present memory blocks
891 *
892 * @arg: argument passed to func
893 * @func: callback for each memory block walked
894 *
895 * This function walks through all present memory blocks, calling func on
896 * each memory block.
897 *
898 * In case func() returns an error, walking is aborted and the error is
899 * returned.
900 */
901int for_each_memory_block(void *arg, walk_memory_blocks_func_t func)
902{
903 struct for_each_memory_block_cb_data cb_data = {
904 .func = func,
905 .arg = arg,
906 };
907
908 return bus_for_each_dev(&memory_subsys, NULL, &cb_data,
909 for_each_memory_block_cb);
910}