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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/*
2 * drivers/base/memory.c - basic Memory class support
3 *
4 * Written by Matt Tolentino <matthew.e.tolentino@intel.com>
5 * Dave Hansen <haveblue@us.ibm.com>
6 *
7 * This file provides the necessary infrastructure to represent
8 * a SPARSEMEM-memory-model system's physical memory in /sysfs.
9 * All arch-independent code that assumes MEMORY_HOTPLUG requires
10 * SPARSEMEM should be contained here, or in mm/memory_hotplug.c.
11 */
12
13#include <linux/sysdev.h>
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/kobject.h>
21#include <linux/memory_hotplug.h>
22#include <linux/mm.h>
23#include <linux/mutex.h>
24#include <linux/stat.h>
25#include <linux/slab.h>
26
27#include <linux/atomic.h>
28#include <asm/uaccess.h>
29
30static DEFINE_MUTEX(mem_sysfs_mutex);
31
32#define MEMORY_CLASS_NAME "memory"
33
34static int sections_per_block;
35
36static inline int base_memory_block_id(int section_nr)
37{
38 return section_nr / sections_per_block;
39}
40
41static struct sysdev_class memory_sysdev_class = {
42 .name = MEMORY_CLASS_NAME,
43};
44
45static const char *memory_uevent_name(struct kset *kset, struct kobject *kobj)
46{
47 return MEMORY_CLASS_NAME;
48}
49
50static int memory_uevent(struct kset *kset, struct kobject *obj,
51 struct kobj_uevent_env *env)
52{
53 int retval = 0;
54
55 return retval;
56}
57
58static const struct kset_uevent_ops memory_uevent_ops = {
59 .name = memory_uevent_name,
60 .uevent = memory_uevent,
61};
62
63static BLOCKING_NOTIFIER_HEAD(memory_chain);
64
65int register_memory_notifier(struct notifier_block *nb)
66{
67 return blocking_notifier_chain_register(&memory_chain, nb);
68}
69EXPORT_SYMBOL(register_memory_notifier);
70
71void unregister_memory_notifier(struct notifier_block *nb)
72{
73 blocking_notifier_chain_unregister(&memory_chain, nb);
74}
75EXPORT_SYMBOL(unregister_memory_notifier);
76
77static ATOMIC_NOTIFIER_HEAD(memory_isolate_chain);
78
79int register_memory_isolate_notifier(struct notifier_block *nb)
80{
81 return atomic_notifier_chain_register(&memory_isolate_chain, nb);
82}
83EXPORT_SYMBOL(register_memory_isolate_notifier);
84
85void unregister_memory_isolate_notifier(struct notifier_block *nb)
86{
87 atomic_notifier_chain_unregister(&memory_isolate_chain, nb);
88}
89EXPORT_SYMBOL(unregister_memory_isolate_notifier);
90
91/*
92 * register_memory - Setup a sysfs device for a memory block
93 */
94static
95int register_memory(struct memory_block *memory)
96{
97 int error;
98
99 memory->sysdev.cls = &memory_sysdev_class;
100 memory->sysdev.id = memory->start_section_nr / sections_per_block;
101
102 error = sysdev_register(&memory->sysdev);
103 return error;
104}
105
106static void
107unregister_memory(struct memory_block *memory)
108{
109 BUG_ON(memory->sysdev.cls != &memory_sysdev_class);
110
111 /* drop the ref. we got in remove_memory_block() */
112 kobject_put(&memory->sysdev.kobj);
113 sysdev_unregister(&memory->sysdev);
114}
115
116unsigned long __weak memory_block_size_bytes(void)
117{
118 return MIN_MEMORY_BLOCK_SIZE;
119}
120
121static unsigned long get_memory_block_size(void)
122{
123 unsigned long block_sz;
124
125 block_sz = memory_block_size_bytes();
126
127 /* Validate blk_sz is a power of 2 and not less than section size */
128 if ((block_sz & (block_sz - 1)) || (block_sz < MIN_MEMORY_BLOCK_SIZE)) {
129 WARN_ON(1);
130 block_sz = MIN_MEMORY_BLOCK_SIZE;
131 }
132
133 return block_sz;
134}
135
136/*
137 * use this as the physical section index that this memsection
138 * uses.
139 */
140
141static ssize_t show_mem_start_phys_index(struct sys_device *dev,
142 struct sysdev_attribute *attr, char *buf)
143{
144 struct memory_block *mem =
145 container_of(dev, struct memory_block, sysdev);
146 unsigned long phys_index;
147
148 phys_index = mem->start_section_nr / sections_per_block;
149 return sprintf(buf, "%08lx\n", phys_index);
150}
151
152static ssize_t show_mem_end_phys_index(struct sys_device *dev,
153 struct sysdev_attribute *attr, char *buf)
154{
155 struct memory_block *mem =
156 container_of(dev, struct memory_block, sysdev);
157 unsigned long phys_index;
158
159 phys_index = mem->end_section_nr / sections_per_block;
160 return sprintf(buf, "%08lx\n", phys_index);
161}
162
163/*
164 * Show whether the section of memory is likely to be hot-removable
165 */
166static ssize_t show_mem_removable(struct sys_device *dev,
167 struct sysdev_attribute *attr, char *buf)
168{
169 unsigned long i, pfn;
170 int ret = 1;
171 struct memory_block *mem =
172 container_of(dev, struct memory_block, sysdev);
173
174 for (i = 0; i < sections_per_block; i++) {
175 pfn = section_nr_to_pfn(mem->start_section_nr + i);
176 ret &= is_mem_section_removable(pfn, PAGES_PER_SECTION);
177 }
178
179 return sprintf(buf, "%d\n", ret);
180}
181
182/*
183 * online, offline, going offline, etc.
184 */
185static ssize_t show_mem_state(struct sys_device *dev,
186 struct sysdev_attribute *attr, char *buf)
187{
188 struct memory_block *mem =
189 container_of(dev, struct memory_block, sysdev);
190 ssize_t len = 0;
191
192 /*
193 * We can probably put these states in a nice little array
194 * so that they're not open-coded
195 */
196 switch (mem->state) {
197 case MEM_ONLINE:
198 len = sprintf(buf, "online\n");
199 break;
200 case MEM_OFFLINE:
201 len = sprintf(buf, "offline\n");
202 break;
203 case MEM_GOING_OFFLINE:
204 len = sprintf(buf, "going-offline\n");
205 break;
206 default:
207 len = sprintf(buf, "ERROR-UNKNOWN-%ld\n",
208 mem->state);
209 WARN_ON(1);
210 break;
211 }
212
213 return len;
214}
215
216int memory_notify(unsigned long val, void *v)
217{
218 return blocking_notifier_call_chain(&memory_chain, val, v);
219}
220
221int memory_isolate_notify(unsigned long val, void *v)
222{
223 return atomic_notifier_call_chain(&memory_isolate_chain, val, v);
224}
225
226/*
227 * MEMORY_HOTPLUG depends on SPARSEMEM in mm/Kconfig, so it is
228 * OK to have direct references to sparsemem variables in here.
229 */
230static int
231memory_block_action(unsigned long phys_index, unsigned long action)
232{
233 int i;
234 unsigned long start_pfn, start_paddr;
235 unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block;
236 struct page *first_page;
237 int ret;
238
239 first_page = pfn_to_page(phys_index << PFN_SECTION_SHIFT);
240
241 /*
242 * The probe routines leave the pages reserved, just
243 * as the bootmem code does. Make sure they're still
244 * that way.
245 */
246 if (action == MEM_ONLINE) {
247 for (i = 0; i < nr_pages; i++) {
248 if (PageReserved(first_page+i))
249 continue;
250
251 printk(KERN_WARNING "section number %ld page number %d "
252 "not reserved, was it already online?\n",
253 phys_index, i);
254 return -EBUSY;
255 }
256 }
257
258 switch (action) {
259 case MEM_ONLINE:
260 start_pfn = page_to_pfn(first_page);
261 ret = online_pages(start_pfn, nr_pages);
262 break;
263 case MEM_OFFLINE:
264 start_paddr = page_to_pfn(first_page) << PAGE_SHIFT;
265 ret = remove_memory(start_paddr,
266 nr_pages << PAGE_SHIFT);
267 break;
268 default:
269 WARN(1, KERN_WARNING "%s(%ld, %ld) unknown action: "
270 "%ld\n", __func__, phys_index, action, action);
271 ret = -EINVAL;
272 }
273
274 return ret;
275}
276
277static int memory_block_change_state(struct memory_block *mem,
278 unsigned long to_state, unsigned long from_state_req)
279{
280 int ret = 0;
281
282 mutex_lock(&mem->state_mutex);
283
284 if (mem->state != from_state_req) {
285 ret = -EINVAL;
286 goto out;
287 }
288
289 if (to_state == MEM_OFFLINE)
290 mem->state = MEM_GOING_OFFLINE;
291
292 ret = memory_block_action(mem->start_section_nr, to_state);
293
294 if (ret)
295 mem->state = from_state_req;
296 else
297 mem->state = to_state;
298
299out:
300 mutex_unlock(&mem->state_mutex);
301 return ret;
302}
303
304static ssize_t
305store_mem_state(struct sys_device *dev,
306 struct sysdev_attribute *attr, const char *buf, size_t count)
307{
308 struct memory_block *mem;
309 int ret = -EINVAL;
310
311 mem = container_of(dev, struct memory_block, sysdev);
312
313 if (!strncmp(buf, "online", min((int)count, 6)))
314 ret = memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE);
315 else if(!strncmp(buf, "offline", min((int)count, 7)))
316 ret = memory_block_change_state(mem, MEM_OFFLINE, MEM_ONLINE);
317
318 if (ret)
319 return ret;
320 return count;
321}
322
323/*
324 * phys_device is a bad name for this. What I really want
325 * is a way to differentiate between memory ranges that
326 * are part of physical devices that constitute
327 * a complete removable unit or fru.
328 * i.e. do these ranges belong to the same physical device,
329 * s.t. if I offline all of these sections I can then
330 * remove the physical device?
331 */
332static ssize_t show_phys_device(struct sys_device *dev,
333 struct sysdev_attribute *attr, char *buf)
334{
335 struct memory_block *mem =
336 container_of(dev, struct memory_block, sysdev);
337 return sprintf(buf, "%d\n", mem->phys_device);
338}
339
340static SYSDEV_ATTR(phys_index, 0444, show_mem_start_phys_index, NULL);
341static SYSDEV_ATTR(end_phys_index, 0444, show_mem_end_phys_index, NULL);
342static SYSDEV_ATTR(state, 0644, show_mem_state, store_mem_state);
343static SYSDEV_ATTR(phys_device, 0444, show_phys_device, NULL);
344static SYSDEV_ATTR(removable, 0444, show_mem_removable, NULL);
345
346#define mem_create_simple_file(mem, attr_name) \
347 sysdev_create_file(&mem->sysdev, &attr_##attr_name)
348#define mem_remove_simple_file(mem, attr_name) \
349 sysdev_remove_file(&mem->sysdev, &attr_##attr_name)
350
351/*
352 * Block size attribute stuff
353 */
354static ssize_t
355print_block_size(struct sysdev_class *class, struct sysdev_class_attribute *attr,
356 char *buf)
357{
358 return sprintf(buf, "%lx\n", get_memory_block_size());
359}
360
361static SYSDEV_CLASS_ATTR(block_size_bytes, 0444, print_block_size, NULL);
362
363static int block_size_init(void)
364{
365 return sysfs_create_file(&memory_sysdev_class.kset.kobj,
366 &attr_block_size_bytes.attr);
367}
368
369/*
370 * Some architectures will have custom drivers to do this, and
371 * will not need to do it from userspace. The fake hot-add code
372 * as well as ppc64 will do all of their discovery in userspace
373 * and will require this interface.
374 */
375#ifdef CONFIG_ARCH_MEMORY_PROBE
376static ssize_t
377memory_probe_store(struct class *class, struct class_attribute *attr,
378 const char *buf, size_t count)
379{
380 u64 phys_addr;
381 int nid;
382 int i, ret;
383
384 phys_addr = simple_strtoull(buf, NULL, 0);
385
386 for (i = 0; i < sections_per_block; i++) {
387 nid = memory_add_physaddr_to_nid(phys_addr);
388 ret = add_memory(nid, phys_addr,
389 PAGES_PER_SECTION << PAGE_SHIFT);
390 if (ret)
391 goto out;
392
393 phys_addr += MIN_MEMORY_BLOCK_SIZE;
394 }
395
396 ret = count;
397out:
398 return ret;
399}
400static CLASS_ATTR(probe, S_IWUSR, NULL, memory_probe_store);
401
402static int memory_probe_init(void)
403{
404 return sysfs_create_file(&memory_sysdev_class.kset.kobj,
405 &class_attr_probe.attr);
406}
407#else
408static inline int memory_probe_init(void)
409{
410 return 0;
411}
412#endif
413
414#ifdef CONFIG_MEMORY_FAILURE
415/*
416 * Support for offlining pages of memory
417 */
418
419/* Soft offline a page */
420static ssize_t
421store_soft_offline_page(struct class *class,
422 struct class_attribute *attr,
423 const char *buf, size_t count)
424{
425 int ret;
426 u64 pfn;
427 if (!capable(CAP_SYS_ADMIN))
428 return -EPERM;
429 if (strict_strtoull(buf, 0, &pfn) < 0)
430 return -EINVAL;
431 pfn >>= PAGE_SHIFT;
432 if (!pfn_valid(pfn))
433 return -ENXIO;
434 ret = soft_offline_page(pfn_to_page(pfn), 0);
435 return ret == 0 ? count : ret;
436}
437
438/* Forcibly offline a page, including killing processes. */
439static ssize_t
440store_hard_offline_page(struct class *class,
441 struct class_attribute *attr,
442 const char *buf, size_t count)
443{
444 int ret;
445 u64 pfn;
446 if (!capable(CAP_SYS_ADMIN))
447 return -EPERM;
448 if (strict_strtoull(buf, 0, &pfn) < 0)
449 return -EINVAL;
450 pfn >>= PAGE_SHIFT;
451 ret = __memory_failure(pfn, 0, 0);
452 return ret ? ret : count;
453}
454
455static CLASS_ATTR(soft_offline_page, 0644, NULL, store_soft_offline_page);
456static CLASS_ATTR(hard_offline_page, 0644, NULL, store_hard_offline_page);
457
458static __init int memory_fail_init(void)
459{
460 int err;
461
462 err = sysfs_create_file(&memory_sysdev_class.kset.kobj,
463 &class_attr_soft_offline_page.attr);
464 if (!err)
465 err = sysfs_create_file(&memory_sysdev_class.kset.kobj,
466 &class_attr_hard_offline_page.attr);
467 return err;
468}
469#else
470static inline int memory_fail_init(void)
471{
472 return 0;
473}
474#endif
475
476/*
477 * Note that phys_device is optional. It is here to allow for
478 * differentiation between which *physical* devices each
479 * section belongs to...
480 */
481int __weak arch_get_memory_phys_device(unsigned long start_pfn)
482{
483 return 0;
484}
485
486struct memory_block *find_memory_block_hinted(struct mem_section *section,
487 struct memory_block *hint)
488{
489 struct kobject *kobj;
490 struct sys_device *sysdev;
491 struct memory_block *mem;
492 char name[sizeof(MEMORY_CLASS_NAME) + 9 + 1];
493 int block_id = base_memory_block_id(__section_nr(section));
494
495 kobj = hint ? &hint->sysdev.kobj : NULL;
496
497 /*
498 * This only works because we know that section == sysdev->id
499 * slightly redundant with sysdev_register()
500 */
501 sprintf(&name[0], "%s%d", MEMORY_CLASS_NAME, block_id);
502
503 kobj = kset_find_obj_hinted(&memory_sysdev_class.kset, name, kobj);
504 if (!kobj)
505 return NULL;
506
507 sysdev = container_of(kobj, struct sys_device, kobj);
508 mem = container_of(sysdev, struct memory_block, sysdev);
509
510 return mem;
511}
512
513/*
514 * For now, we have a linear search to go find the appropriate
515 * memory_block corresponding to a particular phys_index. If
516 * this gets to be a real problem, we can always use a radix
517 * tree or something here.
518 *
519 * This could be made generic for all sysdev classes.
520 */
521struct memory_block *find_memory_block(struct mem_section *section)
522{
523 return find_memory_block_hinted(section, NULL);
524}
525
526static int init_memory_block(struct memory_block **memory,
527 struct mem_section *section, unsigned long state)
528{
529 struct memory_block *mem;
530 unsigned long start_pfn;
531 int scn_nr;
532 int ret = 0;
533
534 mem = kzalloc(sizeof(*mem), GFP_KERNEL);
535 if (!mem)
536 return -ENOMEM;
537
538 scn_nr = __section_nr(section);
539 mem->start_section_nr =
540 base_memory_block_id(scn_nr) * sections_per_block;
541 mem->end_section_nr = mem->start_section_nr + sections_per_block - 1;
542 mem->state = state;
543 mem->section_count++;
544 mutex_init(&mem->state_mutex);
545 start_pfn = section_nr_to_pfn(mem->start_section_nr);
546 mem->phys_device = arch_get_memory_phys_device(start_pfn);
547
548 ret = register_memory(mem);
549 if (!ret)
550 ret = mem_create_simple_file(mem, phys_index);
551 if (!ret)
552 ret = mem_create_simple_file(mem, end_phys_index);
553 if (!ret)
554 ret = mem_create_simple_file(mem, state);
555 if (!ret)
556 ret = mem_create_simple_file(mem, phys_device);
557 if (!ret)
558 ret = mem_create_simple_file(mem, removable);
559
560 *memory = mem;
561 return ret;
562}
563
564static int add_memory_section(int nid, struct mem_section *section,
565 unsigned long state, enum mem_add_context context)
566{
567 struct memory_block *mem;
568 int ret = 0;
569
570 mutex_lock(&mem_sysfs_mutex);
571
572 mem = find_memory_block(section);
573 if (mem) {
574 mem->section_count++;
575 kobject_put(&mem->sysdev.kobj);
576 } else
577 ret = init_memory_block(&mem, section, state);
578
579 if (!ret) {
580 if (context == HOTPLUG &&
581 mem->section_count == sections_per_block)
582 ret = register_mem_sect_under_node(mem, nid);
583 }
584
585 mutex_unlock(&mem_sysfs_mutex);
586 return ret;
587}
588
589int remove_memory_block(unsigned long node_id, struct mem_section *section,
590 int phys_device)
591{
592 struct memory_block *mem;
593
594 mutex_lock(&mem_sysfs_mutex);
595 mem = find_memory_block(section);
596 unregister_mem_sect_under_nodes(mem, __section_nr(section));
597
598 mem->section_count--;
599 if (mem->section_count == 0) {
600 mem_remove_simple_file(mem, phys_index);
601 mem_remove_simple_file(mem, end_phys_index);
602 mem_remove_simple_file(mem, state);
603 mem_remove_simple_file(mem, phys_device);
604 mem_remove_simple_file(mem, removable);
605 unregister_memory(mem);
606 kfree(mem);
607 } else
608 kobject_put(&mem->sysdev.kobj);
609
610 mutex_unlock(&mem_sysfs_mutex);
611 return 0;
612}
613
614/*
615 * need an interface for the VM to add new memory regions,
616 * but without onlining it.
617 */
618int register_new_memory(int nid, struct mem_section *section)
619{
620 return add_memory_section(nid, section, MEM_OFFLINE, HOTPLUG);
621}
622
623int unregister_memory_section(struct mem_section *section)
624{
625 if (!present_section(section))
626 return -EINVAL;
627
628 return remove_memory_block(0, section, 0);
629}
630
631/*
632 * Initialize the sysfs support for memory devices...
633 */
634int __init memory_dev_init(void)
635{
636 unsigned int i;
637 int ret;
638 int err;
639 unsigned long block_sz;
640
641 memory_sysdev_class.kset.uevent_ops = &memory_uevent_ops;
642 ret = sysdev_class_register(&memory_sysdev_class);
643 if (ret)
644 goto out;
645
646 block_sz = get_memory_block_size();
647 sections_per_block = block_sz / MIN_MEMORY_BLOCK_SIZE;
648
649 /*
650 * Create entries for memory sections that were found
651 * during boot and have been initialized
652 */
653 for (i = 0; i < NR_MEM_SECTIONS; i++) {
654 if (!present_section_nr(i))
655 continue;
656 err = add_memory_section(0, __nr_to_section(i), MEM_ONLINE,
657 BOOT);
658 if (!ret)
659 ret = err;
660 }
661
662 err = memory_probe_init();
663 if (!ret)
664 ret = err;
665 err = memory_fail_init();
666 if (!ret)
667 ret = err;
668 err = block_size_init();
669 if (!ret)
670 ret = err;
671out:
672 if (ret)
673 printk(KERN_ERR "%s() failed: %d\n", __func__, ret);
674 return ret;
675}