7dda4f790f00d58145cc3b58ce4607c42ea829b1
[linux-2.6.git] / drivers / base / memory.c
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
29 static DEFINE_MUTEX(mem_sysfs_mutex);
30
31 #define MEMORY_CLASS_NAME       "memory"
32
33 static int sections_per_block;
34
35 static inline int base_memory_block_id(int section_nr)
36 {
37         return section_nr / sections_per_block;
38 }
39
40 static struct bus_type memory_subsys = {
41         .name = MEMORY_CLASS_NAME,
42         .dev_name = MEMORY_CLASS_NAME,
43 };
44
45 static BLOCKING_NOTIFIER_HEAD(memory_chain);
46
47 int register_memory_notifier(struct notifier_block *nb)
48 {
49         return blocking_notifier_chain_register(&memory_chain, nb);
50 }
51 EXPORT_SYMBOL(register_memory_notifier);
52
53 void unregister_memory_notifier(struct notifier_block *nb)
54 {
55         blocking_notifier_chain_unregister(&memory_chain, nb);
56 }
57 EXPORT_SYMBOL(unregister_memory_notifier);
58
59 static ATOMIC_NOTIFIER_HEAD(memory_isolate_chain);
60
61 int register_memory_isolate_notifier(struct notifier_block *nb)
62 {
63         return atomic_notifier_chain_register(&memory_isolate_chain, nb);
64 }
65 EXPORT_SYMBOL(register_memory_isolate_notifier);
66
67 void unregister_memory_isolate_notifier(struct notifier_block *nb)
68 {
69         atomic_notifier_chain_unregister(&memory_isolate_chain, nb);
70 }
71 EXPORT_SYMBOL(unregister_memory_isolate_notifier);
72
73 /*
74  * register_memory - Setup a sysfs device for a memory block
75  */
76 static
77 int 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
88 static void
89 unregister_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
98 unsigned long __weak memory_block_size_bytes(void)
99 {
100         return MIN_MEMORY_BLOCK_SIZE;
101 }
102
103 static 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
123 static 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
134 static 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  */
148 static 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  */
167 static 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
198 int memory_notify(unsigned long val, void *v)
199 {
200         return blocking_notifier_call_chain(&memory_chain, val, v);
201 }
202
203 int 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  */
212 static 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  */
248 static int
249 memory_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
281 static 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         }
314 out:
315         mutex_unlock(&mem->state_mutex);
316         return ret;
317 }
318
319 static ssize_t
320 store_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  */
347 static 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
355 static DEVICE_ATTR(phys_index, 0444, show_mem_start_phys_index, NULL);
356 static DEVICE_ATTR(end_phys_index, 0444, show_mem_end_phys_index, NULL);
357 static DEVICE_ATTR(state, 0644, show_mem_state, store_mem_state);
358 static DEVICE_ATTR(phys_device, 0444, show_phys_device, NULL);
359 static 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  */
369 static ssize_t
370 print_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
376 static DEVICE_ATTR(block_size_bytes, 0444, print_block_size, NULL);
377
378 static 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
391 static ssize_t
392 memory_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;
416 out:
417         return ret;
418 }
419 static DEVICE_ATTR(probe, S_IWUSR, NULL, memory_probe_store);
420
421 static int memory_probe_init(void)
422 {
423         return device_create_file(memory_subsys.dev_root, &dev_attr_probe);
424 }
425 #else
426 static 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 */
438 static ssize_t
439 store_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. */
457 static ssize_t
458 store_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
473 static DEVICE_ATTR(soft_offline_page, 0644, NULL, store_soft_offline_page);
474 static DEVICE_ATTR(hard_offline_page, 0644, NULL, store_hard_offline_page);
475
476 static __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
488 static 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  */
499 int __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  */
508 struct 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  */
531 struct memory_block *find_memory_block(struct mem_section *section)
532 {
533         return find_memory_block_hinted(section, NULL);
534 }
535
536 static 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
574 static 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
616 int 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  */
645 int register_new_memory(int nid, struct mem_section *section)
646 {
647         return add_memory_section(nid, section, NULL, MEM_OFFLINE, HOTPLUG);
648 }
649
650 int 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  */
661 int __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;
701 out:
702         if (ret)
703                 printk(KERN_ERR "%s() failed: %d\n", __func__, ret);
704         return ret;
705 }