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