memory.c 16.7 KB
Newer Older
1
/*
2
 * Memory subsystem support
3 4 5 6 7 8 9 10 11 12 13 14 15
 *
 * Written by Matt Tolentino <matthew.e.tolentino@intel.com>
 *            Dave Hansen <haveblue@us.ibm.com>
 *
 * This file provides the necessary infrastructure to represent
 * a SPARSEMEM-memory-model system's physical memory in /sysfs.
 * All arch-independent code that assumes MEMORY_HOTPLUG requires
 * SPARSEMEM should be contained here, or in mm/memory_hotplug.c.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/topology.h>
16
#include <linux/capability.h>
17 18 19 20 21
#include <linux/device.h>
#include <linux/memory.h>
#include <linux/kobject.h>
#include <linux/memory_hotplug.h>
#include <linux/mm.h>
22
#include <linux/mutex.h>
23
#include <linux/stat.h>
24
#include <linux/slab.h>
25

Arun Sharma's avatar
Arun Sharma committed
26
#include <linux/atomic.h>
27 28
#include <asm/uaccess.h>

29 30
static DEFINE_MUTEX(mem_sysfs_mutex);

31
#define MEMORY_CLASS_NAME	"memory"
32 33 34 35 36 37 38

static int sections_per_block;

static inline int base_memory_block_id(int section_nr)
{
	return section_nr / sections_per_block;
}
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 60 61 62 63 64 65 66 67 68 69 70 71 72
static ATOMIC_NOTIFIER_HEAD(memory_isolate_chain);

int register_memory_isolate_notifier(struct notifier_block *nb)
{
	return atomic_notifier_chain_register(&memory_isolate_chain, nb);
}
EXPORT_SYMBOL(register_memory_isolate_notifier);

void unregister_memory_isolate_notifier(struct notifier_block *nb)
{
	atomic_notifier_chain_unregister(&memory_isolate_chain, nb);
}
EXPORT_SYMBOL(unregister_memory_isolate_notifier);

73 74 75
/*
 * register_memory - Setup a sysfs device for a memory block
 */
76
static
77
int register_memory(struct memory_block *memory)
78 79 80
{
	int error;

81 82
	memory->dev.bus = &memory_subsys;
	memory->dev.id = memory->start_section_nr / sections_per_block;
83

84
	error = device_register(&memory->dev);
85 86 87 88
	return error;
}

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 95
	kobject_put(&memory->dev.kobj);
	device_unregister(&memory->dev);
96 97
}

98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117
unsigned long __weak memory_block_size_bytes(void)
{
	return MIN_MEMORY_BLOCK_SIZE;
}

static unsigned long get_memory_block_size(void)
{
	unsigned long block_sz;

	block_sz = memory_block_size_bytes();

	/* Validate blk_sz is a power of 2 and not less than section size */
	if ((block_sz & (block_sz - 1)) || (block_sz < MIN_MEMORY_BLOCK_SIZE)) {
		WARN_ON(1);
		block_sz = MIN_MEMORY_BLOCK_SIZE;
	}

	return block_sz;
}

118 119 120 121 122
/*
 * use this as the physical section index that this memsection
 * uses.
 */

123 124
static ssize_t show_mem_start_phys_index(struct device *dev,
			struct device_attribute *attr, char *buf)
125 126
{
	struct memory_block *mem =
127
		container_of(dev, struct memory_block, dev);
128 129 130 131 132 133
	unsigned long phys_index;

	phys_index = mem->start_section_nr / sections_per_block;
	return sprintf(buf, "%08lx\n", phys_index);
}

134 135
static ssize_t show_mem_end_phys_index(struct device *dev,
			struct device_attribute *attr, char *buf)
136 137
{
	struct memory_block *mem =
138
		container_of(dev, struct memory_block, dev);
139 140 141 142
	unsigned long phys_index;

	phys_index = mem->end_section_nr / sections_per_block;
	return sprintf(buf, "%08lx\n", phys_index);
143 144
}

145 146 147
/*
 * Show whether the section of memory is likely to be hot-removable
 */
148 149
static ssize_t show_mem_removable(struct device *dev,
			struct device_attribute *attr, char *buf)
150
{
151 152
	unsigned long i, pfn;
	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);
158 159 160
		ret &= is_mem_section_removable(pfn, PAGES_PER_SECTION);
	}

161 162 163
	return sprintf(buf, "%d\n", ret);
}

164 165 166
/*
 * online, offline, going offline, etc.
 */
167 168
static ssize_t show_mem_state(struct device *dev,
			struct device_attribute *attr, char *buf)
169 170
{
	struct memory_block *mem =
171
		container_of(dev, struct memory_block, dev);
172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197
	ssize_t len = 0;

	/*
	 * We can probably put these states in a nice little array
	 * so that they're not open-coded
	 */
	switch (mem->state) {
		case MEM_ONLINE:
			len = sprintf(buf, "online\n");
			break;
		case MEM_OFFLINE:
			len = sprintf(buf, "offline\n");
			break;
		case MEM_GOING_OFFLINE:
			len = sprintf(buf, "going-offline\n");
			break;
		default:
			len = sprintf(buf, "ERROR-UNKNOWN-%ld\n",
					mem->state);
			WARN_ON(1);
			break;
	}

	return len;
}

198
int memory_notify(unsigned long val, void *v)
199
{
200
	return blocking_notifier_call_chain(&memory_chain, val, v);
201 202
}

203 204 205 206 207
int memory_isolate_notify(unsigned long val, void *v)
{
	return atomic_notifier_call_chain(&memory_isolate_chain, val, v);
}

208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243
/*
 * The probe routines leave the pages reserved, just as the bootmem code does.
 * Make sure they're still that way.
 */
static bool pages_correctly_reserved(unsigned long start_pfn,
					unsigned long nr_pages)
{
	int i, j;
	struct page *page;
	unsigned long pfn = start_pfn;

	/*
	 * memmap between sections is not contiguous except with
	 * SPARSEMEM_VMEMMAP. We lookup the page once per section
	 * and assume memmap is contiguous within each section
	 */
	for (i = 0; i < sections_per_block; i++, pfn += PAGES_PER_SECTION) {
		if (WARN_ON_ONCE(!pfn_valid(pfn)))
			return false;
		page = pfn_to_page(pfn);

		for (j = 0; j < PAGES_PER_SECTION; j++) {
			if (PageReserved(page + j))
				continue;

			printk(KERN_WARNING "section number %ld page number %d "
				"not reserved, was it already online?\n",
				pfn_to_section_nr(pfn), j);

			return false;
		}
	}

	return true;
}

244 245 246 247 248
/*
 * MEMORY_HOTPLUG depends on SPARSEMEM in mm/Kconfig, so it is
 * OK to have direct references to sparsemem variables in here.
 */
static int
249
memory_block_action(unsigned long phys_index, unsigned long action)
250
{
251
	unsigned long start_pfn;
252
	unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block;
253
	struct page *first_page;
254 255
	int ret;

256
	first_page = pfn_to_page(phys_index << PFN_SECTION_SHIFT);
257
	start_pfn = page_to_pfn(first_page);
258

259 260
	switch (action) {
		case MEM_ONLINE:
261 262 263
			if (!pages_correctly_reserved(start_pfn, nr_pages))
				return -EBUSY;

264
			ret = online_pages(start_pfn, nr_pages);
265 266
			break;
		case MEM_OFFLINE:
267
			ret = offline_pages(start_pfn, nr_pages);
268 269
			break;
		default:
270 271
			WARN(1, KERN_WARNING "%s(%ld, %ld) unknown action: "
			     "%ld\n", __func__, phys_index, action, action);
272 273 274 275 276 277 278 279 280
			ret = -EINVAL;
	}

	return ret;
}

static int memory_block_change_state(struct memory_block *mem,
		unsigned long to_state, unsigned long from_state_req)
{
281
	int ret = 0;
282

283
	mutex_lock(&mem->state_mutex);
284 285 286 287 288 289

	if (mem->state != from_state_req) {
		ret = -EINVAL;
		goto out;
	}

290 291 292
	if (to_state == MEM_OFFLINE)
		mem->state = MEM_GOING_OFFLINE;

293
	ret = memory_block_action(mem->start_section_nr, to_state);
294

295
	if (ret) {
296
		mem->state = from_state_req;
297 298
		goto out;
	}
299

300 301 302 303 304 305 306 307 308 309 310
	mem->state = to_state;
	switch (mem->state) {
	case MEM_OFFLINE:
		kobject_uevent(&mem->dev.kobj, KOBJ_OFFLINE);
		break;
	case MEM_ONLINE:
		kobject_uevent(&mem->dev.kobj, KOBJ_ONLINE);
		break;
	default:
		break;
	}
311
out:
312
	mutex_unlock(&mem->state_mutex);
313 314 315 316
	return ret;
}

static ssize_t
317 318
store_mem_state(struct device *dev,
		struct device_attribute *attr, const char *buf, size_t count)
319 320 321 322
{
	struct memory_block *mem;
	int ret = -EINVAL;

323
	mem = container_of(dev, struct memory_block, dev);
324 325 326 327 328

	if (!strncmp(buf, "online", min((int)count, 6)))
		ret = memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE);
	else if(!strncmp(buf, "offline", min((int)count, 7)))
		ret = memory_block_change_state(mem, MEM_OFFLINE, MEM_ONLINE);
329

330 331 332 333 334 335 336 337 338 339 340 341 342 343
	if (ret)
		return ret;
	return count;
}

/*
 * phys_device is a bad name for this.  What I really want
 * is a way to differentiate between memory ranges that
 * are part of physical devices that constitute
 * a complete removable unit or fru.
 * i.e. do these ranges belong to the same physical device,
 * s.t. if I offline all of these sections I can then
 * remove the physical device?
 */
344 345
static ssize_t show_phys_device(struct device *dev,
				struct device_attribute *attr, char *buf)
346 347
{
	struct memory_block *mem =
348
		container_of(dev, struct memory_block, dev);
349 350 351
	return sprintf(buf, "%d\n", mem->phys_device);
}

352 353 354 355 356
static DEVICE_ATTR(phys_index, 0444, show_mem_start_phys_index, NULL);
static DEVICE_ATTR(end_phys_index, 0444, show_mem_end_phys_index, NULL);
static DEVICE_ATTR(state, 0644, show_mem_state, store_mem_state);
static DEVICE_ATTR(phys_device, 0444, show_phys_device, NULL);
static DEVICE_ATTR(removable, 0444, show_mem_removable, NULL);
357 358

#define mem_create_simple_file(mem, attr_name)	\
359
	device_create_file(&mem->dev, &dev_attr_##attr_name)
360
#define mem_remove_simple_file(mem, attr_name)	\
361
	device_remove_file(&mem->dev, &dev_attr_##attr_name)
362 363 364 365 366

/*
 * Block size attribute stuff
 */
static ssize_t
367
print_block_size(struct device *dev, struct device_attribute *attr,
368
		 char *buf)
369
{
370
	return sprintf(buf, "%lx\n", get_memory_block_size());
371 372
}

373
static DEVICE_ATTR(block_size_bytes, 0444, print_block_size, NULL);
374 375 376

static int block_size_init(void)
{
377 378
	return device_create_file(memory_subsys.dev_root,
				  &dev_attr_block_size_bytes);
379 380 381 382 383 384 385 386 387 388
}

/*
 * Some architectures will have custom drivers to do this, and
 * will not need to do it from userspace.  The fake hot-add code
 * as well as ppc64 will do all of their discovery in userspace
 * and will require this interface.
 */
#ifdef CONFIG_ARCH_MEMORY_PROBE
static ssize_t
389
memory_probe_store(struct device *dev, struct device_attribute *attr,
390
		   const char *buf, size_t count)
391 392
{
	u64 phys_addr;
393
	int nid;
394
	int i, ret;
395
	unsigned long pages_per_block = PAGES_PER_SECTION * sections_per_block;
396 397 398

	phys_addr = simple_strtoull(buf, NULL, 0);

399 400 401
	if (phys_addr & ((pages_per_block << PAGE_SHIFT) - 1))
		return -EINVAL;

402 403 404 405 406
	for (i = 0; i < sections_per_block; i++) {
		nid = memory_add_physaddr_to_nid(phys_addr);
		ret = add_memory(nid, phys_addr,
				 PAGES_PER_SECTION << PAGE_SHIFT);
		if (ret)
407
			goto out;
408 409 410

		phys_addr += MIN_MEMORY_BLOCK_SIZE;
	}
411

412 413 414
	ret = count;
out:
	return ret;
415
}
416
static DEVICE_ATTR(probe, S_IWUSR, NULL, memory_probe_store);
417 418 419

static int memory_probe_init(void)
{
420
	return device_create_file(memory_subsys.dev_root, &dev_attr_probe);
421 422
}
#else
423 424 425 426
static inline int memory_probe_init(void)
{
	return 0;
}
427 428
#endif

429 430 431 432 433 434 435
#ifdef CONFIG_MEMORY_FAILURE
/*
 * Support for offlining pages of memory
 */

/* Soft offline a page */
static ssize_t
436 437
store_soft_offline_page(struct device *dev,
			struct device_attribute *attr,
438
			const char *buf, size_t count)
439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454
{
	int ret;
	u64 pfn;
	if (!capable(CAP_SYS_ADMIN))
		return -EPERM;
	if (strict_strtoull(buf, 0, &pfn) < 0)
		return -EINVAL;
	pfn >>= PAGE_SHIFT;
	if (!pfn_valid(pfn))
		return -ENXIO;
	ret = soft_offline_page(pfn_to_page(pfn), 0);
	return ret == 0 ? count : ret;
}

/* Forcibly offline a page, including killing processes. */
static ssize_t
455 456
store_hard_offline_page(struct device *dev,
			struct device_attribute *attr,
457
			const char *buf, size_t count)
458 459 460 461 462 463 464 465
{
	int ret;
	u64 pfn;
	if (!capable(CAP_SYS_ADMIN))
		return -EPERM;
	if (strict_strtoull(buf, 0, &pfn) < 0)
		return -EINVAL;
	pfn >>= PAGE_SHIFT;
466
	ret = memory_failure(pfn, 0, 0);
467 468 469
	return ret ? ret : count;
}

470 471
static DEVICE_ATTR(soft_offline_page, 0644, NULL, store_soft_offline_page);
static DEVICE_ATTR(hard_offline_page, 0644, NULL, store_hard_offline_page);
472 473 474 475 476

static __init int memory_fail_init(void)
{
	int err;

477 478
	err = device_create_file(memory_subsys.dev_root,
				&dev_attr_soft_offline_page);
479
	if (!err)
480 481
		err = device_create_file(memory_subsys.dev_root,
				&dev_attr_hard_offline_page);
482 483 484 485 486 487 488 489 490
	return err;
}
#else
static inline int memory_fail_init(void)
{
	return 0;
}
#endif

491 492 493 494 495
/*
 * Note that phys_device is optional.  It is here to allow for
 * differentiation between which *physical* devices each
 * section belongs to...
 */
496 497 498 499
int __weak arch_get_memory_phys_device(unsigned long start_pfn)
{
	return 0;
}
500

501 502 503 504
/*
 * A reference for the returned object is held and the reference for the
 * hinted object is released.
 */
505 506
struct memory_block *find_memory_block_hinted(struct mem_section *section,
					      struct memory_block *hint)
507
{
508
	int block_id = base_memory_block_id(__section_nr(section));
509 510
	struct device *hintdev = hint ? &hint->dev : NULL;
	struct device *dev;
511

512 513 514 515
	dev = subsys_find_device_by_id(&memory_subsys, block_id, hintdev);
	if (hint)
		put_device(&hint->dev);
	if (!dev)
516
		return NULL;
517
	return container_of(dev, struct memory_block, dev);
518 519
}

520 521 522 523 524 525
/*
 * For now, we have a linear search to go find the appropriate
 * memory_block corresponding to a particular phys_index. If
 * this gets to be a real problem, we can always use a radix
 * tree or something here.
 *
526
 * This could be made generic for all device subsystems.
527 528 529 530 531 532
 */
struct memory_block *find_memory_block(struct mem_section *section)
{
	return find_memory_block_hinted(section, NULL);
}

533 534
static int init_memory_block(struct memory_block **memory,
			     struct mem_section *section, unsigned long state)
535
{
536
	struct memory_block *mem;
537
	unsigned long start_pfn;
538
	int scn_nr;
539 540
	int ret = 0;

541
	mem = kzalloc(sizeof(*mem), GFP_KERNEL);
542 543 544
	if (!mem)
		return -ENOMEM;

545
	scn_nr = __section_nr(section);
546 547 548
	mem->start_section_nr =
			base_memory_block_id(scn_nr) * sections_per_block;
	mem->end_section_nr = mem->start_section_nr + sections_per_block - 1;
549
	mem->state = state;
550
	mem->section_count++;
551
	mutex_init(&mem->state_mutex);
552
	start_pfn = section_nr_to_pfn(mem->start_section_nr);
553 554
	mem->phys_device = arch_get_memory_phys_device(start_pfn);

555
	ret = register_memory(mem);
556 557
	if (!ret)
		ret = mem_create_simple_file(mem, phys_index);
558 559
	if (!ret)
		ret = mem_create_simple_file(mem, end_phys_index);
560 561 562 563 564 565
	if (!ret)
		ret = mem_create_simple_file(mem, state);
	if (!ret)
		ret = mem_create_simple_file(mem, phys_device);
	if (!ret)
		ret = mem_create_simple_file(mem, removable);
566 567 568 569 570 571

	*memory = mem;
	return ret;
}

static int add_memory_section(int nid, struct mem_section *section,
572
			struct memory_block **mem_p,
573 574
			unsigned long state, enum mem_add_context context)
{
575 576
	struct memory_block *mem = NULL;
	int scn_nr = __section_nr(section);
577 578 579 580
	int ret = 0;

	mutex_lock(&mem_sysfs_mutex);

581 582 583 584 585 586 587 588 589 590 591
	if (context == BOOT) {
		/* same memory block ? */
		if (mem_p && *mem_p)
			if (scn_nr >= (*mem_p)->start_section_nr &&
			    scn_nr <= (*mem_p)->end_section_nr) {
				mem = *mem_p;
				kobject_get(&mem->dev.kobj);
			}
	} else
		mem = find_memory_block(section);

592 593
	if (mem) {
		mem->section_count++;
594
		kobject_put(&mem->dev.kobj);
595
	} else {
596
		ret = init_memory_block(&mem, section, state);
597 598 599 600 601
		/* store memory_block pointer for next loop */
		if (!ret && context == BOOT)
			if (mem_p)
				*mem_p = mem;
	}
602

603
	if (!ret) {
604 605
		if (context == HOTPLUG &&
		    mem->section_count == sections_per_block)
606 607 608
			ret = register_mem_sect_under_node(mem, nid);
	}

609
	mutex_unlock(&mem_sysfs_mutex);
610 611 612
	return ret;
}

613 614 615 616 617
int remove_memory_block(unsigned long node_id, struct mem_section *section,
		int phys_device)
{
	struct memory_block *mem;

618
	mutex_lock(&mem_sysfs_mutex);
619
	mem = find_memory_block(section);
620
	unregister_mem_sect_under_nodes(mem, __section_nr(section));
621 622 623 624

	mem->section_count--;
	if (mem->section_count == 0) {
		mem_remove_simple_file(mem, phys_index);
625
		mem_remove_simple_file(mem, end_phys_index);
626 627 628
		mem_remove_simple_file(mem, state);
		mem_remove_simple_file(mem, phys_device);
		mem_remove_simple_file(mem, removable);
629 630 631
		unregister_memory(mem);
		kfree(mem);
	} else
632
		kobject_put(&mem->dev.kobj);
633

634
	mutex_unlock(&mem_sysfs_mutex);
635 636 637 638 639 640 641
	return 0;
}

/*
 * need an interface for the VM to add new memory regions,
 * but without onlining it.
 */
642
int register_new_memory(int nid, struct mem_section *section)
643
{
644
	return add_memory_section(nid, section, NULL, MEM_OFFLINE, HOTPLUG);
645 646 647 648
}

int unregister_memory_section(struct mem_section *section)
{
649
	if (!present_section(section))
650 651 652 653 654 655 656 657 658 659 660 661
		return -EINVAL;

	return remove_memory_block(0, section, 0);
}

/*
 * Initialize the sysfs support for memory devices...
 */
int __init memory_dev_init(void)
{
	unsigned int i;
	int ret;
662
	int err;
663
	unsigned long block_sz;
664
	struct memory_block *mem = NULL;
665

666
	ret = subsys_system_register(&memory_subsys, NULL);
667 668
	if (ret)
		goto out;
669

670 671 672
	block_sz = get_memory_block_size();
	sections_per_block = block_sz / MIN_MEMORY_BLOCK_SIZE;

673 674 675 676 677
	/*
	 * Create entries for memory sections that were found
	 * during boot and have been initialized
	 */
	for (i = 0; i < NR_MEM_SECTIONS; i++) {
678
		if (!present_section_nr(i))
679
			continue;
680 681 682 683
		/* don't need to reuse memory_block if only one per block */
		err = add_memory_section(0, __nr_to_section(i),
				 (sections_per_block == 1) ? NULL : &mem,
					 MEM_ONLINE,
684
					 BOOT);
685 686
		if (!ret)
			ret = err;
687 688
	}

689
	err = memory_probe_init();
690 691 692
	if (!ret)
		ret = err;
	err = memory_fail_init();
693 694 695 696 697 698 699
	if (!ret)
		ret = err;
	err = block_size_init();
	if (!ret)
		ret = err;
out:
	if (ret)
700
		printk(KERN_ERR "%s() failed: %d\n", __func__, ret);
701 702
	return ret;
}