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