convert 'memory' sysdev_class to a regular subsystem
[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         else
301                 mem->state = to_state;
302
303 out:
304         mutex_unlock(&mem->state_mutex);
305         return ret;
306 }
307
308 static ssize_t
309 store_mem_state(struct device *dev,
310                 struct device_attribute *attr, const char *buf, size_t count)
311 {
312         struct memory_block *mem;
313         int ret = -EINVAL;
314
315         mem = container_of(dev, struct memory_block, dev);
316
317         if (!strncmp(buf, "online", min((int)count, 6)))
318                 ret = memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE);
319         else if(!strncmp(buf, "offline", min((int)count, 7)))
320                 ret = memory_block_change_state(mem, MEM_OFFLINE, MEM_ONLINE);
321
322         if (ret)
323                 return ret;
324         return count;
325 }
326
327 /*
328  * phys_device is a bad name for this.  What I really want
329  * is a way to differentiate between memory ranges that
330  * are part of physical devices that constitute
331  * a complete removable unit or fru.
332  * i.e. do these ranges belong to the same physical device,
333  * s.t. if I offline all of these sections I can then
334  * remove the physical device?
335  */
336 static ssize_t show_phys_device(struct device *dev,
337                                 struct device_attribute *attr, char *buf)
338 {
339         struct memory_block *mem =
340                 container_of(dev, struct memory_block, dev);
341         return sprintf(buf, "%d\n", mem->phys_device);
342 }
343
344 static DEVICE_ATTR(phys_index, 0444, show_mem_start_phys_index, NULL);
345 static DEVICE_ATTR(end_phys_index, 0444, show_mem_end_phys_index, NULL);
346 static DEVICE_ATTR(state, 0644, show_mem_state, store_mem_state);
347 static DEVICE_ATTR(phys_device, 0444, show_phys_device, NULL);
348 static DEVICE_ATTR(removable, 0444, show_mem_removable, NULL);
349
350 #define mem_create_simple_file(mem, attr_name)  \
351         device_create_file(&mem->dev, &dev_attr_##attr_name)
352 #define mem_remove_simple_file(mem, attr_name)  \
353         device_remove_file(&mem->dev, &dev_attr_##attr_name)
354
355 /*
356  * Block size attribute stuff
357  */
358 static ssize_t
359 print_block_size(struct device *dev, struct device_attribute *attr,
360                  char *buf)
361 {
362         return sprintf(buf, "%lx\n", get_memory_block_size());
363 }
364
365 static DEVICE_ATTR(block_size_bytes, 0444, print_block_size, NULL);
366
367 static int block_size_init(void)
368 {
369         return device_create_file(memory_subsys.dev_root,
370                                   &dev_attr_block_size_bytes);
371 }
372
373 /*
374  * Some architectures will have custom drivers to do this, and
375  * will not need to do it from userspace.  The fake hot-add code
376  * as well as ppc64 will do all of their discovery in userspace
377  * and will require this interface.
378  */
379 #ifdef CONFIG_ARCH_MEMORY_PROBE
380 static ssize_t
381 memory_probe_store(struct device *dev, struct device_attribute *attr,
382                    const char *buf, size_t count)
383 {
384         u64 phys_addr;
385         int nid;
386         int i, ret;
387         unsigned long pages_per_block = PAGES_PER_SECTION * sections_per_block;
388
389         phys_addr = simple_strtoull(buf, NULL, 0);
390
391         if (phys_addr & ((pages_per_block << PAGE_SHIFT) - 1))
392                 return -EINVAL;
393
394         for (i = 0; i < sections_per_block; i++) {
395                 nid = memory_add_physaddr_to_nid(phys_addr);
396                 ret = add_memory(nid, phys_addr,
397                                  PAGES_PER_SECTION << PAGE_SHIFT);
398                 if (ret)
399                         goto out;
400
401                 phys_addr += MIN_MEMORY_BLOCK_SIZE;
402         }
403
404         ret = count;
405 out:
406         return ret;
407 }
408 static DEVICE_ATTR(probe, S_IWUSR, NULL, memory_probe_store);
409
410 static int memory_probe_init(void)
411 {
412         return device_create_file(memory_subsys.dev_root, &dev_attr_probe);
413 }
414 #else
415 static inline int memory_probe_init(void)
416 {
417         return 0;
418 }
419 #endif
420
421 #ifdef CONFIG_MEMORY_FAILURE
422 /*
423  * Support for offlining pages of memory
424  */
425
426 /* Soft offline a page */
427 static ssize_t
428 store_soft_offline_page(struct device *dev,
429                         struct device_attribute *attr,
430                         const char *buf, size_t count)
431 {
432         int ret;
433         u64 pfn;
434         if (!capable(CAP_SYS_ADMIN))
435                 return -EPERM;
436         if (strict_strtoull(buf, 0, &pfn) < 0)
437                 return -EINVAL;
438         pfn >>= PAGE_SHIFT;
439         if (!pfn_valid(pfn))
440                 return -ENXIO;
441         ret = soft_offline_page(pfn_to_page(pfn), 0);
442         return ret == 0 ? count : ret;
443 }
444
445 /* Forcibly offline a page, including killing processes. */
446 static ssize_t
447 store_hard_offline_page(struct device *dev,
448                         struct device_attribute *attr,
449                         const char *buf, size_t count)
450 {
451         int ret;
452         u64 pfn;
453         if (!capable(CAP_SYS_ADMIN))
454                 return -EPERM;
455         if (strict_strtoull(buf, 0, &pfn) < 0)
456                 return -EINVAL;
457         pfn >>= PAGE_SHIFT;
458         ret = __memory_failure(pfn, 0, 0);
459         return ret ? ret : count;
460 }
461
462 static DEVICE_ATTR(soft_offline_page, 0644, NULL, store_soft_offline_page);
463 static DEVICE_ATTR(hard_offline_page, 0644, NULL, store_hard_offline_page);
464
465 static __init int memory_fail_init(void)
466 {
467         int err;
468
469         err = device_create_file(memory_subsys.dev_root,
470                                 &dev_attr_soft_offline_page);
471         if (!err)
472                 err = device_create_file(memory_subsys.dev_root,
473                                 &dev_attr_hard_offline_page);
474         return err;
475 }
476 #else
477 static inline int memory_fail_init(void)
478 {
479         return 0;
480 }
481 #endif
482
483 /*
484  * Note that phys_device is optional.  It is here to allow for
485  * differentiation between which *physical* devices each
486  * section belongs to...
487  */
488 int __weak arch_get_memory_phys_device(unsigned long start_pfn)
489 {
490         return 0;
491 }
492
493 /*
494  * A reference for the returned object is held and the reference for the
495  * hinted object is released.
496  */
497 struct memory_block *find_memory_block_hinted(struct mem_section *section,
498                                               struct memory_block *hint)
499 {
500         int block_id = base_memory_block_id(__section_nr(section));
501         struct device *hintdev = hint ? &hint->dev : NULL;
502         struct device *dev;
503
504         dev = subsys_find_device_by_id(&memory_subsys, block_id, hintdev);
505         if (hint)
506                 put_device(&hint->dev);
507         if (!dev)
508                 return NULL;
509         return container_of(dev, struct memory_block, dev);
510 }
511
512 /*
513  * For now, we have a linear search to go find the appropriate
514  * memory_block corresponding to a particular phys_index. If
515  * this gets to be a real problem, we can always use a radix
516  * tree or something here.
517  *
518  * This could be made generic for all device subsystems.
519  */
520 struct memory_block *find_memory_block(struct mem_section *section)
521 {
522         return find_memory_block_hinted(section, NULL);
523 }
524
525 static int init_memory_block(struct memory_block **memory,
526                              struct mem_section *section, unsigned long state)
527 {
528         struct memory_block *mem;
529         unsigned long start_pfn;
530         int scn_nr;
531         int ret = 0;
532
533         mem = kzalloc(sizeof(*mem), GFP_KERNEL);
534         if (!mem)
535                 return -ENOMEM;
536
537         scn_nr = __section_nr(section);
538         mem->start_section_nr =
539                         base_memory_block_id(scn_nr) * sections_per_block;
540         mem->end_section_nr = mem->start_section_nr + sections_per_block - 1;
541         mem->state = state;
542         mem->section_count++;
543         mutex_init(&mem->state_mutex);
544         start_pfn = section_nr_to_pfn(mem->start_section_nr);
545         mem->phys_device = arch_get_memory_phys_device(start_pfn);
546
547         ret = register_memory(mem);
548         if (!ret)
549                 ret = mem_create_simple_file(mem, phys_index);
550         if (!ret)
551                 ret = mem_create_simple_file(mem, end_phys_index);
552         if (!ret)
553                 ret = mem_create_simple_file(mem, state);
554         if (!ret)
555                 ret = mem_create_simple_file(mem, phys_device);
556         if (!ret)
557                 ret = mem_create_simple_file(mem, removable);
558
559         *memory = mem;
560         return ret;
561 }
562
563 static int add_memory_section(int nid, struct mem_section *section,
564                         unsigned long state, enum mem_add_context context)
565 {
566         struct memory_block *mem;
567         int ret = 0;
568
569         mutex_lock(&mem_sysfs_mutex);
570
571         mem = find_memory_block(section);
572         if (mem) {
573                 mem->section_count++;
574                 kobject_put(&mem->dev.kobj);
575         } else
576                 ret = init_memory_block(&mem, section, state);
577
578         if (!ret) {
579                 if (context == HOTPLUG &&
580                     mem->section_count == sections_per_block)
581                         ret = register_mem_sect_under_node(mem, nid);
582         }
583
584         mutex_unlock(&mem_sysfs_mutex);
585         return ret;
586 }
587
588 int remove_memory_block(unsigned long node_id, struct mem_section *section,
589                 int phys_device)
590 {
591         struct memory_block *mem;
592
593         mutex_lock(&mem_sysfs_mutex);
594         mem = find_memory_block(section);
595         unregister_mem_sect_under_nodes(mem, __section_nr(section));
596
597         mem->section_count--;
598         if (mem->section_count == 0) {
599                 mem_remove_simple_file(mem, phys_index);
600                 mem_remove_simple_file(mem, end_phys_index);
601                 mem_remove_simple_file(mem, state);
602                 mem_remove_simple_file(mem, phys_device);
603                 mem_remove_simple_file(mem, removable);
604                 unregister_memory(mem);
605                 kfree(mem);
606         } else
607                 kobject_put(&mem->dev.kobj);
608
609         mutex_unlock(&mem_sysfs_mutex);
610         return 0;
611 }
612
613 /*
614  * need an interface for the VM to add new memory regions,
615  * but without onlining it.
616  */
617 int register_new_memory(int nid, struct mem_section *section)
618 {
619         return add_memory_section(nid, section, MEM_OFFLINE, HOTPLUG);
620 }
621
622 int unregister_memory_section(struct mem_section *section)
623 {
624         if (!present_section(section))
625                 return -EINVAL;
626
627         return remove_memory_block(0, section, 0);
628 }
629
630 /*
631  * Initialize the sysfs support for memory devices...
632  */
633 int __init memory_dev_init(void)
634 {
635         unsigned int i;
636         int ret;
637         int err;
638         unsigned long block_sz;
639
640         ret = subsys_system_register(&memory_subsys, NULL);
641         if (ret)
642                 goto out;
643
644         block_sz = get_memory_block_size();
645         sections_per_block = block_sz / MIN_MEMORY_BLOCK_SIZE;
646
647         /*
648          * Create entries for memory sections that were found
649          * during boot and have been initialized
650          */
651         for (i = 0; i < NR_MEM_SECTIONS; i++) {
652                 if (!present_section_nr(i))
653                         continue;
654                 err = add_memory_section(0, __nr_to_section(i), MEM_ONLINE,
655                                          BOOT);
656                 if (!ret)
657                         ret = err;
658         }
659
660         err = memory_probe_init();
661         if (!ret)
662                 ret = err;
663         err = memory_fail_init();
664         if (!ret)
665                 ret = err;
666         err = block_size_init();
667         if (!ret)
668                 ret = err;
669 out:
670         if (ret)
671                 printk(KERN_ERR "%s() failed: %d\n", __func__, ret);
672         return ret;
673 }