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 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 class *class, char *buf) 313 { 314 return sprintf(buf, "%#lx\n", (unsigned long)PAGES_PER_SECTION * PAGE_SIZE); 315 } 316 317 static CLASS_ATTR(block_size_bytes, 0444, print_block_size, NULL); 318 319 static int block_size_init(void) 320 { 321 return sysfs_create_file(&memory_sysdev_class.kset.kobj, 322 &class_attr_block_size_bytes.attr); 323 } 324 325 /* 326 * Some architectures will have custom drivers to do this, and 327 * will not need to do it from userspace. The fake hot-add code 328 * as well as ppc64 will do all of their discovery in userspace 329 * and will require this interface. 330 */ 331 #ifdef CONFIG_ARCH_MEMORY_PROBE 332 static ssize_t 333 memory_probe_store(struct class *class, const char *buf, size_t count) 334 { 335 u64 phys_addr; 336 int nid; 337 int ret; 338 339 phys_addr = simple_strtoull(buf, NULL, 0); 340 341 nid = memory_add_physaddr_to_nid(phys_addr); 342 ret = add_memory(nid, phys_addr, PAGES_PER_SECTION << PAGE_SHIFT); 343 344 if (ret) 345 count = ret; 346 347 return count; 348 } 349 static CLASS_ATTR(probe, S_IWUSR, NULL, memory_probe_store); 350 351 static int memory_probe_init(void) 352 { 353 return sysfs_create_file(&memory_sysdev_class.kset.kobj, 354 &class_attr_probe.attr); 355 } 356 #else 357 static inline int memory_probe_init(void) 358 { 359 return 0; 360 } 361 #endif 362 363 #ifdef CONFIG_MEMORY_FAILURE 364 /* 365 * Support for offlining pages of memory 366 */ 367 368 /* Soft offline a page */ 369 static ssize_t 370 store_soft_offline_page(struct class *class, const char *buf, size_t count) 371 { 372 int ret; 373 u64 pfn; 374 if (!capable(CAP_SYS_ADMIN)) 375 return -EPERM; 376 if (strict_strtoull(buf, 0, &pfn) < 0) 377 return -EINVAL; 378 pfn >>= PAGE_SHIFT; 379 if (!pfn_valid(pfn)) 380 return -ENXIO; 381 ret = soft_offline_page(pfn_to_page(pfn), 0); 382 return ret == 0 ? count : ret; 383 } 384 385 /* Forcibly offline a page, including killing processes. */ 386 static ssize_t 387 store_hard_offline_page(struct class *class, const char *buf, size_t count) 388 { 389 int ret; 390 u64 pfn; 391 if (!capable(CAP_SYS_ADMIN)) 392 return -EPERM; 393 if (strict_strtoull(buf, 0, &pfn) < 0) 394 return -EINVAL; 395 pfn >>= PAGE_SHIFT; 396 ret = __memory_failure(pfn, 0, 0); 397 return ret ? ret : count; 398 } 399 400 static CLASS_ATTR(soft_offline_page, 0644, NULL, store_soft_offline_page); 401 static CLASS_ATTR(hard_offline_page, 0644, NULL, store_hard_offline_page); 402 403 static __init int memory_fail_init(void) 404 { 405 int err; 406 407 err = sysfs_create_file(&memory_sysdev_class.kset.kobj, 408 &class_attr_soft_offline_page.attr); 409 if (!err) 410 err = sysfs_create_file(&memory_sysdev_class.kset.kobj, 411 &class_attr_hard_offline_page.attr); 412 return err; 413 } 414 #else 415 static inline int memory_fail_init(void) 416 { 417 return 0; 418 } 419 #endif 420 421 /* 422 * Note that phys_device is optional. It is here to allow for 423 * differentiation between which *physical* devices each 424 * section belongs to... 425 */ 426 427 static int add_memory_block(int nid, struct mem_section *section, 428 unsigned long state, int phys_device, 429 enum mem_add_context context) 430 { 431 struct memory_block *mem = kzalloc(sizeof(*mem), GFP_KERNEL); 432 int ret = 0; 433 434 if (!mem) 435 return -ENOMEM; 436 437 mem->phys_index = __section_nr(section); 438 mem->state = state; 439 mutex_init(&mem->state_mutex); 440 mem->phys_device = phys_device; 441 442 ret = register_memory(mem, section); 443 if (!ret) 444 ret = mem_create_simple_file(mem, phys_index); 445 if (!ret) 446 ret = mem_create_simple_file(mem, state); 447 if (!ret) 448 ret = mem_create_simple_file(mem, phys_device); 449 if (!ret) 450 ret = mem_create_simple_file(mem, removable); 451 if (!ret) { 452 if (context == HOTPLUG) 453 ret = register_mem_sect_under_node(mem, nid); 454 } 455 456 return ret; 457 } 458 459 /* 460 * For now, we have a linear search to go find the appropriate 461 * memory_block corresponding to a particular phys_index. If 462 * this gets to be a real problem, we can always use a radix 463 * tree or something here. 464 * 465 * This could be made generic for all sysdev classes. 466 */ 467 struct memory_block *find_memory_block(struct mem_section *section) 468 { 469 struct kobject *kobj; 470 struct sys_device *sysdev; 471 struct memory_block *mem; 472 char name[sizeof(MEMORY_CLASS_NAME) + 9 + 1]; 473 474 /* 475 * This only works because we know that section == sysdev->id 476 * slightly redundant with sysdev_register() 477 */ 478 sprintf(&name[0], "%s%d", MEMORY_CLASS_NAME, __section_nr(section)); 479 480 kobj = kset_find_obj(&memory_sysdev_class.kset, name); 481 if (!kobj) 482 return NULL; 483 484 sysdev = container_of(kobj, struct sys_device, kobj); 485 mem = container_of(sysdev, struct memory_block, sysdev); 486 487 return mem; 488 } 489 490 int remove_memory_block(unsigned long node_id, struct mem_section *section, 491 int phys_device) 492 { 493 struct memory_block *mem; 494 495 mem = find_memory_block(section); 496 unregister_mem_sect_under_nodes(mem); 497 mem_remove_simple_file(mem, phys_index); 498 mem_remove_simple_file(mem, state); 499 mem_remove_simple_file(mem, phys_device); 500 mem_remove_simple_file(mem, removable); 501 unregister_memory(mem, section); 502 503 return 0; 504 } 505 506 /* 507 * need an interface for the VM to add new memory regions, 508 * but without onlining it. 509 */ 510 int register_new_memory(int nid, struct mem_section *section) 511 { 512 return add_memory_block(nid, section, MEM_OFFLINE, 0, HOTPLUG); 513 } 514 515 int unregister_memory_section(struct mem_section *section) 516 { 517 if (!present_section(section)) 518 return -EINVAL; 519 520 return remove_memory_block(0, section, 0); 521 } 522 523 /* 524 * Initialize the sysfs support for memory devices... 525 */ 526 int __init memory_dev_init(void) 527 { 528 unsigned int i; 529 int ret; 530 int err; 531 532 memory_sysdev_class.kset.uevent_ops = &memory_uevent_ops; 533 ret = sysdev_class_register(&memory_sysdev_class); 534 if (ret) 535 goto out; 536 537 /* 538 * Create entries for memory sections that were found 539 * during boot and have been initialized 540 */ 541 for (i = 0; i < NR_MEM_SECTIONS; i++) { 542 if (!present_section_nr(i)) 543 continue; 544 err = add_memory_block(0, __nr_to_section(i), MEM_ONLINE, 545 0, BOOT); 546 if (!ret) 547 ret = err; 548 } 549 550 err = memory_probe_init(); 551 if (!ret) 552 ret = err; 553 err = memory_fail_init(); 554 if (!ret) 555 ret = err; 556 err = block_size_init(); 557 if (!ret) 558 ret = err; 559 out: 560 if (ret) 561 printk(KERN_ERR "%s() failed: %d\n", __func__, ret); 562 return ret; 563 } 564