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