Loading...
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}
1/*
2 * Memory subsystem support
3 *
4 * Written by Matt Tolentino <matthew.e.tolentino@intel.com>
5 * Dave Hansen <haveblue@us.ibm.com>
6 *
7 * This file provides the necessary infrastructure to represent
8 * a SPARSEMEM-memory-model system's physical memory in /sysfs.
9 * All arch-independent code that assumes MEMORY_HOTPLUG requires
10 * SPARSEMEM should be contained here, or in mm/memory_hotplug.c.
11 */
12
13#include <linux/module.h>
14#include <linux/init.h>
15#include <linux/topology.h>
16#include <linux/capability.h>
17#include <linux/device.h>
18#include <linux/memory.h>
19#include <linux/kobject.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 <asm/uaccess.h>
28
29static DEFINE_MUTEX(mem_sysfs_mutex);
30
31#define MEMORY_CLASS_NAME "memory"
32
33static int sections_per_block;
34
35static inline int base_memory_block_id(int section_nr)
36{
37 return section_nr / sections_per_block;
38}
39
40static struct bus_type memory_subsys = {
41 .name = MEMORY_CLASS_NAME,
42 .dev_name = MEMORY_CLASS_NAME,
43};
44
45static BLOCKING_NOTIFIER_HEAD(memory_chain);
46
47int register_memory_notifier(struct notifier_block *nb)
48{
49 return blocking_notifier_chain_register(&memory_chain, nb);
50}
51EXPORT_SYMBOL(register_memory_notifier);
52
53void unregister_memory_notifier(struct notifier_block *nb)
54{
55 blocking_notifier_chain_unregister(&memory_chain, nb);
56}
57EXPORT_SYMBOL(unregister_memory_notifier);
58
59static ATOMIC_NOTIFIER_HEAD(memory_isolate_chain);
60
61int register_memory_isolate_notifier(struct notifier_block *nb)
62{
63 return atomic_notifier_chain_register(&memory_isolate_chain, nb);
64}
65EXPORT_SYMBOL(register_memory_isolate_notifier);
66
67void unregister_memory_isolate_notifier(struct notifier_block *nb)
68{
69 atomic_notifier_chain_unregister(&memory_isolate_chain, nb);
70}
71EXPORT_SYMBOL(unregister_memory_isolate_notifier);
72
73/*
74 * register_memory - Setup a sysfs device for a memory block
75 */
76static
77int register_memory(struct memory_block *memory)
78{
79 int error;
80
81 memory->dev.bus = &memory_subsys;
82 memory->dev.id = memory->start_section_nr / sections_per_block;
83
84 error = device_register(&memory->dev);
85 return error;
86}
87
88static void
89unregister_memory(struct memory_block *memory)
90{
91 BUG_ON(memory->dev.bus != &memory_subsys);
92
93 /* drop the ref. we got in remove_memory_block() */
94 kobject_put(&memory->dev.kobj);
95 device_unregister(&memory->dev);
96}
97
98unsigned long __weak memory_block_size_bytes(void)
99{
100 return MIN_MEMORY_BLOCK_SIZE;
101}
102
103static unsigned long get_memory_block_size(void)
104{
105 unsigned long block_sz;
106
107 block_sz = memory_block_size_bytes();
108
109 /* Validate blk_sz is a power of 2 and not less than section size */
110 if ((block_sz & (block_sz - 1)) || (block_sz < MIN_MEMORY_BLOCK_SIZE)) {
111 WARN_ON(1);
112 block_sz = MIN_MEMORY_BLOCK_SIZE;
113 }
114
115 return block_sz;
116}
117
118/*
119 * use this as the physical section index that this memsection
120 * uses.
121 */
122
123static ssize_t show_mem_start_phys_index(struct device *dev,
124 struct device_attribute *attr, char *buf)
125{
126 struct memory_block *mem =
127 container_of(dev, struct memory_block, dev);
128 unsigned long phys_index;
129
130 phys_index = mem->start_section_nr / sections_per_block;
131 return sprintf(buf, "%08lx\n", phys_index);
132}
133
134static ssize_t show_mem_end_phys_index(struct device *dev,
135 struct device_attribute *attr, char *buf)
136{
137 struct memory_block *mem =
138 container_of(dev, struct memory_block, dev);
139 unsigned long phys_index;
140
141 phys_index = mem->end_section_nr / sections_per_block;
142 return sprintf(buf, "%08lx\n", phys_index);
143}
144
145/*
146 * Show whether the section of memory is likely to be hot-removable
147 */
148static ssize_t show_mem_removable(struct device *dev,
149 struct device_attribute *attr, char *buf)
150{
151 unsigned long i, pfn;
152 int ret = 1;
153 struct memory_block *mem =
154 container_of(dev, struct memory_block, dev);
155
156 for (i = 0; i < sections_per_block; i++) {
157 pfn = section_nr_to_pfn(mem->start_section_nr + i);
158 ret &= is_mem_section_removable(pfn, PAGES_PER_SECTION);
159 }
160
161 return sprintf(buf, "%d\n", ret);
162}
163
164/*
165 * online, offline, going offline, etc.
166 */
167static ssize_t show_mem_state(struct device *dev,
168 struct device_attribute *attr, char *buf)
169{
170 struct memory_block *mem =
171 container_of(dev, struct memory_block, dev);
172 ssize_t len = 0;
173
174 /*
175 * We can probably put these states in a nice little array
176 * so that they're not open-coded
177 */
178 switch (mem->state) {
179 case MEM_ONLINE:
180 len = sprintf(buf, "online\n");
181 break;
182 case MEM_OFFLINE:
183 len = sprintf(buf, "offline\n");
184 break;
185 case MEM_GOING_OFFLINE:
186 len = sprintf(buf, "going-offline\n");
187 break;
188 default:
189 len = sprintf(buf, "ERROR-UNKNOWN-%ld\n",
190 mem->state);
191 WARN_ON(1);
192 break;
193 }
194
195 return len;
196}
197
198int memory_notify(unsigned long val, void *v)
199{
200 return blocking_notifier_call_chain(&memory_chain, val, v);
201}
202
203int memory_isolate_notify(unsigned long val, void *v)
204{
205 return atomic_notifier_call_chain(&memory_isolate_chain, val, v);
206}
207
208/*
209 * The probe routines leave the pages reserved, just as the bootmem code does.
210 * Make sure they're still that way.
211 */
212static bool pages_correctly_reserved(unsigned long start_pfn,
213 unsigned long nr_pages)
214{
215 int i, j;
216 struct page *page;
217 unsigned long pfn = start_pfn;
218
219 /*
220 * memmap between sections is not contiguous except with
221 * SPARSEMEM_VMEMMAP. We lookup the page once per section
222 * and assume memmap is contiguous within each section
223 */
224 for (i = 0; i < sections_per_block; i++, pfn += PAGES_PER_SECTION) {
225 if (WARN_ON_ONCE(!pfn_valid(pfn)))
226 return false;
227 page = pfn_to_page(pfn);
228
229 for (j = 0; j < PAGES_PER_SECTION; j++) {
230 if (PageReserved(page + j))
231 continue;
232
233 printk(KERN_WARNING "section number %ld page number %d "
234 "not reserved, was it already online?\n",
235 pfn_to_section_nr(pfn), j);
236
237 return false;
238 }
239 }
240
241 return true;
242}
243
244/*
245 * MEMORY_HOTPLUG depends on SPARSEMEM in mm/Kconfig, so it is
246 * OK to have direct references to sparsemem variables in here.
247 */
248static int
249memory_block_action(unsigned long phys_index, unsigned long action)
250{
251 unsigned long start_pfn, start_paddr;
252 unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block;
253 struct page *first_page;
254 int ret;
255
256 first_page = pfn_to_page(phys_index << PFN_SECTION_SHIFT);
257
258 switch (action) {
259 case MEM_ONLINE:
260 start_pfn = page_to_pfn(first_page);
261
262 if (!pages_correctly_reserved(start_pfn, nr_pages))
263 return -EBUSY;
264
265 ret = online_pages(start_pfn, nr_pages);
266 break;
267 case MEM_OFFLINE:
268 start_paddr = page_to_pfn(first_page) << PAGE_SHIFT;
269 ret = remove_memory(start_paddr,
270 nr_pages << PAGE_SHIFT);
271 break;
272 default:
273 WARN(1, KERN_WARNING "%s(%ld, %ld) unknown action: "
274 "%ld\n", __func__, phys_index, action, action);
275 ret = -EINVAL;
276 }
277
278 return ret;
279}
280
281static int memory_block_change_state(struct memory_block *mem,
282 unsigned long to_state, unsigned long from_state_req)
283{
284 int ret = 0;
285
286 mutex_lock(&mem->state_mutex);
287
288 if (mem->state != from_state_req) {
289 ret = -EINVAL;
290 goto out;
291 }
292
293 if (to_state == MEM_OFFLINE)
294 mem->state = MEM_GOING_OFFLINE;
295
296 ret = memory_block_action(mem->start_section_nr, to_state);
297
298 if (ret) {
299 mem->state = from_state_req;
300 goto out;
301 }
302
303 mem->state = to_state;
304 switch (mem->state) {
305 case MEM_OFFLINE:
306 kobject_uevent(&mem->dev.kobj, KOBJ_OFFLINE);
307 break;
308 case MEM_ONLINE:
309 kobject_uevent(&mem->dev.kobj, KOBJ_ONLINE);
310 break;
311 default:
312 break;
313 }
314out:
315 mutex_unlock(&mem->state_mutex);
316 return ret;
317}
318
319static ssize_t
320store_mem_state(struct device *dev,
321 struct device_attribute *attr, const char *buf, size_t count)
322{
323 struct memory_block *mem;
324 int ret = -EINVAL;
325
326 mem = container_of(dev, struct memory_block, dev);
327
328 if (!strncmp(buf, "online", min((int)count, 6)))
329 ret = memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE);
330 else if(!strncmp(buf, "offline", min((int)count, 7)))
331 ret = memory_block_change_state(mem, MEM_OFFLINE, MEM_ONLINE);
332
333 if (ret)
334 return ret;
335 return count;
336}
337
338/*
339 * phys_device is a bad name for this. What I really want
340 * is a way to differentiate between memory ranges that
341 * are part of physical devices that constitute
342 * a complete removable unit or fru.
343 * i.e. do these ranges belong to the same physical device,
344 * s.t. if I offline all of these sections I can then
345 * remove the physical device?
346 */
347static ssize_t show_phys_device(struct device *dev,
348 struct device_attribute *attr, char *buf)
349{
350 struct memory_block *mem =
351 container_of(dev, struct memory_block, dev);
352 return sprintf(buf, "%d\n", mem->phys_device);
353}
354
355static DEVICE_ATTR(phys_index, 0444, show_mem_start_phys_index, NULL);
356static DEVICE_ATTR(end_phys_index, 0444, show_mem_end_phys_index, NULL);
357static DEVICE_ATTR(state, 0644, show_mem_state, store_mem_state);
358static DEVICE_ATTR(phys_device, 0444, show_phys_device, NULL);
359static DEVICE_ATTR(removable, 0444, show_mem_removable, NULL);
360
361#define mem_create_simple_file(mem, attr_name) \
362 device_create_file(&mem->dev, &dev_attr_##attr_name)
363#define mem_remove_simple_file(mem, attr_name) \
364 device_remove_file(&mem->dev, &dev_attr_##attr_name)
365
366/*
367 * Block size attribute stuff
368 */
369static ssize_t
370print_block_size(struct device *dev, struct device_attribute *attr,
371 char *buf)
372{
373 return sprintf(buf, "%lx\n", get_memory_block_size());
374}
375
376static DEVICE_ATTR(block_size_bytes, 0444, print_block_size, NULL);
377
378static int block_size_init(void)
379{
380 return device_create_file(memory_subsys.dev_root,
381 &dev_attr_block_size_bytes);
382}
383
384/*
385 * Some architectures will have custom drivers to do this, and
386 * will not need to do it from userspace. The fake hot-add code
387 * as well as ppc64 will do all of their discovery in userspace
388 * and will require this interface.
389 */
390#ifdef CONFIG_ARCH_MEMORY_PROBE
391static ssize_t
392memory_probe_store(struct device *dev, struct device_attribute *attr,
393 const char *buf, size_t count)
394{
395 u64 phys_addr;
396 int nid;
397 int i, ret;
398 unsigned long pages_per_block = PAGES_PER_SECTION * sections_per_block;
399
400 phys_addr = simple_strtoull(buf, NULL, 0);
401
402 if (phys_addr & ((pages_per_block << PAGE_SHIFT) - 1))
403 return -EINVAL;
404
405 for (i = 0; i < sections_per_block; i++) {
406 nid = memory_add_physaddr_to_nid(phys_addr);
407 ret = add_memory(nid, phys_addr,
408 PAGES_PER_SECTION << PAGE_SHIFT);
409 if (ret)
410 goto out;
411
412 phys_addr += MIN_MEMORY_BLOCK_SIZE;
413 }
414
415 ret = count;
416out:
417 return ret;
418}
419static DEVICE_ATTR(probe, S_IWUSR, NULL, memory_probe_store);
420
421static int memory_probe_init(void)
422{
423 return device_create_file(memory_subsys.dev_root, &dev_attr_probe);
424}
425#else
426static inline int memory_probe_init(void)
427{
428 return 0;
429}
430#endif
431
432#ifdef CONFIG_MEMORY_FAILURE
433/*
434 * Support for offlining pages of memory
435 */
436
437/* Soft offline a page */
438static ssize_t
439store_soft_offline_page(struct device *dev,
440 struct device_attribute *attr,
441 const char *buf, size_t count)
442{
443 int ret;
444 u64 pfn;
445 if (!capable(CAP_SYS_ADMIN))
446 return -EPERM;
447 if (strict_strtoull(buf, 0, &pfn) < 0)
448 return -EINVAL;
449 pfn >>= PAGE_SHIFT;
450 if (!pfn_valid(pfn))
451 return -ENXIO;
452 ret = soft_offline_page(pfn_to_page(pfn), 0);
453 return ret == 0 ? count : ret;
454}
455
456/* Forcibly offline a page, including killing processes. */
457static ssize_t
458store_hard_offline_page(struct device *dev,
459 struct device_attribute *attr,
460 const char *buf, size_t count)
461{
462 int ret;
463 u64 pfn;
464 if (!capable(CAP_SYS_ADMIN))
465 return -EPERM;
466 if (strict_strtoull(buf, 0, &pfn) < 0)
467 return -EINVAL;
468 pfn >>= PAGE_SHIFT;
469 ret = memory_failure(pfn, 0, 0);
470 return ret ? ret : count;
471}
472
473static DEVICE_ATTR(soft_offline_page, 0644, NULL, store_soft_offline_page);
474static DEVICE_ATTR(hard_offline_page, 0644, NULL, store_hard_offline_page);
475
476static __init int memory_fail_init(void)
477{
478 int err;
479
480 err = device_create_file(memory_subsys.dev_root,
481 &dev_attr_soft_offline_page);
482 if (!err)
483 err = device_create_file(memory_subsys.dev_root,
484 &dev_attr_hard_offline_page);
485 return err;
486}
487#else
488static inline int memory_fail_init(void)
489{
490 return 0;
491}
492#endif
493
494/*
495 * Note that phys_device is optional. It is here to allow for
496 * differentiation between which *physical* devices each
497 * section belongs to...
498 */
499int __weak arch_get_memory_phys_device(unsigned long start_pfn)
500{
501 return 0;
502}
503
504/*
505 * A reference for the returned object is held and the reference for the
506 * hinted object is released.
507 */
508struct memory_block *find_memory_block_hinted(struct mem_section *section,
509 struct memory_block *hint)
510{
511 int block_id = base_memory_block_id(__section_nr(section));
512 struct device *hintdev = hint ? &hint->dev : NULL;
513 struct device *dev;
514
515 dev = subsys_find_device_by_id(&memory_subsys, block_id, hintdev);
516 if (hint)
517 put_device(&hint->dev);
518 if (!dev)
519 return NULL;
520 return container_of(dev, struct memory_block, dev);
521}
522
523/*
524 * For now, we have a linear search to go find the appropriate
525 * memory_block corresponding to a particular phys_index. If
526 * this gets to be a real problem, we can always use a radix
527 * tree or something here.
528 *
529 * This could be made generic for all device subsystems.
530 */
531struct memory_block *find_memory_block(struct mem_section *section)
532{
533 return find_memory_block_hinted(section, NULL);
534}
535
536static int init_memory_block(struct memory_block **memory,
537 struct mem_section *section, unsigned long state)
538{
539 struct memory_block *mem;
540 unsigned long start_pfn;
541 int scn_nr;
542 int ret = 0;
543
544 mem = kzalloc(sizeof(*mem), GFP_KERNEL);
545 if (!mem)
546 return -ENOMEM;
547
548 scn_nr = __section_nr(section);
549 mem->start_section_nr =
550 base_memory_block_id(scn_nr) * sections_per_block;
551 mem->end_section_nr = mem->start_section_nr + sections_per_block - 1;
552 mem->state = state;
553 mem->section_count++;
554 mutex_init(&mem->state_mutex);
555 start_pfn = section_nr_to_pfn(mem->start_section_nr);
556 mem->phys_device = arch_get_memory_phys_device(start_pfn);
557
558 ret = register_memory(mem);
559 if (!ret)
560 ret = mem_create_simple_file(mem, phys_index);
561 if (!ret)
562 ret = mem_create_simple_file(mem, end_phys_index);
563 if (!ret)
564 ret = mem_create_simple_file(mem, state);
565 if (!ret)
566 ret = mem_create_simple_file(mem, phys_device);
567 if (!ret)
568 ret = mem_create_simple_file(mem, removable);
569
570 *memory = mem;
571 return ret;
572}
573
574static int add_memory_section(int nid, struct mem_section *section,
575 struct memory_block **mem_p,
576 unsigned long state, enum mem_add_context context)
577{
578 struct memory_block *mem = NULL;
579 int scn_nr = __section_nr(section);
580 int ret = 0;
581
582 mutex_lock(&mem_sysfs_mutex);
583
584 if (context == BOOT) {
585 /* same memory block ? */
586 if (mem_p && *mem_p)
587 if (scn_nr >= (*mem_p)->start_section_nr &&
588 scn_nr <= (*mem_p)->end_section_nr) {
589 mem = *mem_p;
590 kobject_get(&mem->dev.kobj);
591 }
592 } else
593 mem = find_memory_block(section);
594
595 if (mem) {
596 mem->section_count++;
597 kobject_put(&mem->dev.kobj);
598 } else {
599 ret = init_memory_block(&mem, section, state);
600 /* store memory_block pointer for next loop */
601 if (!ret && context == BOOT)
602 if (mem_p)
603 *mem_p = mem;
604 }
605
606 if (!ret) {
607 if (context == HOTPLUG &&
608 mem->section_count == sections_per_block)
609 ret = register_mem_sect_under_node(mem, nid);
610 }
611
612 mutex_unlock(&mem_sysfs_mutex);
613 return ret;
614}
615
616int remove_memory_block(unsigned long node_id, struct mem_section *section,
617 int phys_device)
618{
619 struct memory_block *mem;
620
621 mutex_lock(&mem_sysfs_mutex);
622 mem = find_memory_block(section);
623 unregister_mem_sect_under_nodes(mem, __section_nr(section));
624
625 mem->section_count--;
626 if (mem->section_count == 0) {
627 mem_remove_simple_file(mem, phys_index);
628 mem_remove_simple_file(mem, end_phys_index);
629 mem_remove_simple_file(mem, state);
630 mem_remove_simple_file(mem, phys_device);
631 mem_remove_simple_file(mem, removable);
632 unregister_memory(mem);
633 kfree(mem);
634 } else
635 kobject_put(&mem->dev.kobj);
636
637 mutex_unlock(&mem_sysfs_mutex);
638 return 0;
639}
640
641/*
642 * need an interface for the VM to add new memory regions,
643 * but without onlining it.
644 */
645int register_new_memory(int nid, struct mem_section *section)
646{
647 return add_memory_section(nid, section, NULL, MEM_OFFLINE, HOTPLUG);
648}
649
650int unregister_memory_section(struct mem_section *section)
651{
652 if (!present_section(section))
653 return -EINVAL;
654
655 return remove_memory_block(0, section, 0);
656}
657
658/*
659 * Initialize the sysfs support for memory devices...
660 */
661int __init memory_dev_init(void)
662{
663 unsigned int i;
664 int ret;
665 int err;
666 unsigned long block_sz;
667 struct memory_block *mem = NULL;
668
669 ret = subsys_system_register(&memory_subsys, NULL);
670 if (ret)
671 goto out;
672
673 block_sz = get_memory_block_size();
674 sections_per_block = block_sz / MIN_MEMORY_BLOCK_SIZE;
675
676 /*
677 * Create entries for memory sections that were found
678 * during boot and have been initialized
679 */
680 for (i = 0; i < NR_MEM_SECTIONS; i++) {
681 if (!present_section_nr(i))
682 continue;
683 /* don't need to reuse memory_block if only one per block */
684 err = add_memory_section(0, __nr_to_section(i),
685 (sections_per_block == 1) ? NULL : &mem,
686 MEM_ONLINE,
687 BOOT);
688 if (!ret)
689 ret = err;
690 }
691
692 err = memory_probe_init();
693 if (!ret)
694 ret = err;
695 err = memory_fail_init();
696 if (!ret)
697 ret = err;
698 err = block_size_init();
699 if (!ret)
700 ret = err;
701out:
702 if (ret)
703 printk(KERN_ERR "%s() failed: %d\n", __func__, ret);
704 return ret;
705}