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 <asm/atomic.h> 25 #include <asm/uaccess.h> 26 27 #define MEMORY_CLASS_NAME "memory" 28 29 static struct sysdev_class memory_sysdev_class = { 30 .name = MEMORY_CLASS_NAME, 31 }; 32 33 static const char *memory_uevent_name(struct kset *kset, struct kobject *kobj) 34 { 35 return MEMORY_CLASS_NAME; 36 } 37 38 static int memory_uevent(struct kset *kset, struct kobject *obj, struct kobj_uevent_env *env) 39 { 40 int retval = 0; 41 42 return retval; 43 } 44 45 static struct kset_uevent_ops memory_uevent_ops = { 46 .name = memory_uevent_name, 47 .uevent = memory_uevent, 48 }; 49 50 static BLOCKING_NOTIFIER_HEAD(memory_chain); 51 52 int register_memory_notifier(struct notifier_block *nb) 53 { 54 return blocking_notifier_chain_register(&memory_chain, nb); 55 } 56 EXPORT_SYMBOL(register_memory_notifier); 57 58 void unregister_memory_notifier(struct notifier_block *nb) 59 { 60 blocking_notifier_chain_unregister(&memory_chain, nb); 61 } 62 EXPORT_SYMBOL(unregister_memory_notifier); 63 64 /* 65 * register_memory - Setup a sysfs device for a memory block 66 */ 67 static 68 int register_memory(struct memory_block *memory, struct mem_section *section) 69 { 70 int error; 71 72 memory->sysdev.cls = &memory_sysdev_class; 73 memory->sysdev.id = __section_nr(section); 74 75 error = sysdev_register(&memory->sysdev); 76 return error; 77 } 78 79 static void 80 unregister_memory(struct memory_block *memory, struct mem_section *section) 81 { 82 BUG_ON(memory->sysdev.cls != &memory_sysdev_class); 83 BUG_ON(memory->sysdev.id != __section_nr(section)); 84 85 /* drop the ref. we got in remove_memory_block() */ 86 kobject_put(&memory->sysdev.kobj); 87 sysdev_unregister(&memory->sysdev); 88 } 89 90 /* 91 * use this as the physical section index that this memsection 92 * uses. 93 */ 94 95 static ssize_t show_mem_phys_index(struct sys_device *dev, 96 struct sysdev_attribute *attr, char *buf) 97 { 98 struct memory_block *mem = 99 container_of(dev, struct memory_block, sysdev); 100 return sprintf(buf, "%08lx\n", mem->phys_index); 101 } 102 103 /* 104 * Show whether the section of memory is likely to be hot-removable 105 */ 106 static ssize_t show_mem_removable(struct sys_device *dev, 107 struct sysdev_attribute *attr, char *buf) 108 { 109 unsigned long start_pfn; 110 int ret; 111 struct memory_block *mem = 112 container_of(dev, struct memory_block, sysdev); 113 114 start_pfn = section_nr_to_pfn(mem->phys_index); 115 ret = is_mem_section_removable(start_pfn, PAGES_PER_SECTION); 116 return sprintf(buf, "%d\n", ret); 117 } 118 119 /* 120 * online, offline, going offline, etc. 121 */ 122 static ssize_t show_mem_state(struct sys_device *dev, 123 struct sysdev_attribute *attr, char *buf) 124 { 125 struct memory_block *mem = 126 container_of(dev, struct memory_block, sysdev); 127 ssize_t len = 0; 128 129 /* 130 * We can probably put these states in a nice little array 131 * so that they're not open-coded 132 */ 133 switch (mem->state) { 134 case MEM_ONLINE: 135 len = sprintf(buf, "online\n"); 136 break; 137 case MEM_OFFLINE: 138 len = sprintf(buf, "offline\n"); 139 break; 140 case MEM_GOING_OFFLINE: 141 len = sprintf(buf, "going-offline\n"); 142 break; 143 default: 144 len = sprintf(buf, "ERROR-UNKNOWN-%ld\n", 145 mem->state); 146 WARN_ON(1); 147 break; 148 } 149 150 return len; 151 } 152 153 int memory_notify(unsigned long val, void *v) 154 { 155 return blocking_notifier_call_chain(&memory_chain, val, v); 156 } 157 158 /* 159 * MEMORY_HOTPLUG depends on SPARSEMEM in mm/Kconfig, so it is 160 * OK to have direct references to sparsemem variables in here. 161 */ 162 static int 163 memory_block_action(struct memory_block *mem, unsigned long action) 164 { 165 int i; 166 unsigned long psection; 167 unsigned long start_pfn, start_paddr; 168 struct page *first_page; 169 int ret; 170 int old_state = mem->state; 171 172 psection = mem->phys_index; 173 first_page = pfn_to_page(psection << PFN_SECTION_SHIFT); 174 175 /* 176 * The probe routines leave the pages reserved, just 177 * as the bootmem code does. Make sure they're still 178 * that way. 179 */ 180 if (action == MEM_ONLINE) { 181 for (i = 0; i < PAGES_PER_SECTION; i++) { 182 if (PageReserved(first_page+i)) 183 continue; 184 185 printk(KERN_WARNING "section number %ld page number %d " 186 "not reserved, was it already online? \n", 187 psection, i); 188 return -EBUSY; 189 } 190 } 191 192 switch (action) { 193 case MEM_ONLINE: 194 start_pfn = page_to_pfn(first_page); 195 ret = online_pages(start_pfn, PAGES_PER_SECTION); 196 break; 197 case MEM_OFFLINE: 198 mem->state = MEM_GOING_OFFLINE; 199 start_paddr = page_to_pfn(first_page) << PAGE_SHIFT; 200 ret = remove_memory(start_paddr, 201 PAGES_PER_SECTION << PAGE_SHIFT); 202 if (ret) { 203 mem->state = old_state; 204 break; 205 } 206 break; 207 default: 208 WARN(1, KERN_WARNING "%s(%p, %ld) unknown action: %ld\n", 209 __func__, mem, action, action); 210 ret = -EINVAL; 211 } 212 213 return ret; 214 } 215 216 static int memory_block_change_state(struct memory_block *mem, 217 unsigned long to_state, unsigned long from_state_req) 218 { 219 int ret = 0; 220 mutex_lock(&mem->state_mutex); 221 222 if (mem->state != from_state_req) { 223 ret = -EINVAL; 224 goto out; 225 } 226 227 ret = memory_block_action(mem, to_state); 228 if (!ret) 229 mem->state = to_state; 230 231 out: 232 mutex_unlock(&mem->state_mutex); 233 return ret; 234 } 235 236 static ssize_t 237 store_mem_state(struct sys_device *dev, 238 struct sysdev_attribute *attr, const char *buf, size_t count) 239 { 240 struct memory_block *mem; 241 unsigned int phys_section_nr; 242 int ret = -EINVAL; 243 244 mem = container_of(dev, struct memory_block, sysdev); 245 phys_section_nr = mem->phys_index; 246 247 if (!present_section_nr(phys_section_nr)) 248 goto out; 249 250 if (!strncmp(buf, "online", min((int)count, 6))) 251 ret = memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE); 252 else if(!strncmp(buf, "offline", min((int)count, 7))) 253 ret = memory_block_change_state(mem, MEM_OFFLINE, MEM_ONLINE); 254 out: 255 if (ret) 256 return ret; 257 return count; 258 } 259 260 /* 261 * phys_device is a bad name for this. What I really want 262 * is a way to differentiate between memory ranges that 263 * are part of physical devices that constitute 264 * a complete removable unit or fru. 265 * i.e. do these ranges belong to the same physical device, 266 * s.t. if I offline all of these sections I can then 267 * remove the physical device? 268 */ 269 static ssize_t show_phys_device(struct sys_device *dev, 270 struct sysdev_attribute *attr, char *buf) 271 { 272 struct memory_block *mem = 273 container_of(dev, struct memory_block, sysdev); 274 return sprintf(buf, "%d\n", mem->phys_device); 275 } 276 277 static SYSDEV_ATTR(phys_index, 0444, show_mem_phys_index, NULL); 278 static SYSDEV_ATTR(state, 0644, show_mem_state, store_mem_state); 279 static SYSDEV_ATTR(phys_device, 0444, show_phys_device, NULL); 280 static SYSDEV_ATTR(removable, 0444, show_mem_removable, NULL); 281 282 #define mem_create_simple_file(mem, attr_name) \ 283 sysdev_create_file(&mem->sysdev, &attr_##attr_name) 284 #define mem_remove_simple_file(mem, attr_name) \ 285 sysdev_remove_file(&mem->sysdev, &attr_##attr_name) 286 287 /* 288 * Block size attribute stuff 289 */ 290 static ssize_t 291 print_block_size(struct class *class, char *buf) 292 { 293 return sprintf(buf, "%lx\n", (unsigned long)PAGES_PER_SECTION * PAGE_SIZE); 294 } 295 296 static CLASS_ATTR(block_size_bytes, 0444, print_block_size, NULL); 297 298 static int block_size_init(void) 299 { 300 return sysfs_create_file(&memory_sysdev_class.kset.kobj, 301 &class_attr_block_size_bytes.attr); 302 } 303 304 /* 305 * Some architectures will have custom drivers to do this, and 306 * will not need to do it from userspace. The fake hot-add code 307 * as well as ppc64 will do all of their discovery in userspace 308 * and will require this interface. 309 */ 310 #ifdef CONFIG_ARCH_MEMORY_PROBE 311 static ssize_t 312 memory_probe_store(struct class *class, const char *buf, size_t count) 313 { 314 u64 phys_addr; 315 int nid; 316 int ret; 317 318 phys_addr = simple_strtoull(buf, NULL, 0); 319 320 nid = memory_add_physaddr_to_nid(phys_addr); 321 ret = add_memory(nid, phys_addr, PAGES_PER_SECTION << PAGE_SHIFT); 322 323 if (ret) 324 count = ret; 325 326 return count; 327 } 328 static CLASS_ATTR(probe, 0700, NULL, memory_probe_store); 329 330 static int memory_probe_init(void) 331 { 332 return sysfs_create_file(&memory_sysdev_class.kset.kobj, 333 &class_attr_probe.attr); 334 } 335 #else 336 static inline int memory_probe_init(void) 337 { 338 return 0; 339 } 340 #endif 341 342 /* 343 * Note that phys_device is optional. It is here to allow for 344 * differentiation between which *physical* devices each 345 * section belongs to... 346 */ 347 348 static int add_memory_block(unsigned long node_id, struct mem_section *section, 349 unsigned long state, int phys_device) 350 { 351 struct memory_block *mem = kzalloc(sizeof(*mem), GFP_KERNEL); 352 int ret = 0; 353 354 if (!mem) 355 return -ENOMEM; 356 357 mem->phys_index = __section_nr(section); 358 mem->state = state; 359 mutex_init(&mem->state_mutex); 360 mem->phys_device = phys_device; 361 362 ret = register_memory(mem, section); 363 if (!ret) 364 ret = mem_create_simple_file(mem, phys_index); 365 if (!ret) 366 ret = mem_create_simple_file(mem, state); 367 if (!ret) 368 ret = mem_create_simple_file(mem, phys_device); 369 if (!ret) 370 ret = mem_create_simple_file(mem, removable); 371 372 return ret; 373 } 374 375 /* 376 * For now, we have a linear search to go find the appropriate 377 * memory_block corresponding to a particular phys_index. If 378 * this gets to be a real problem, we can always use a radix 379 * tree or something here. 380 * 381 * This could be made generic for all sysdev classes. 382 */ 383 static struct memory_block *find_memory_block(struct mem_section *section) 384 { 385 struct kobject *kobj; 386 struct sys_device *sysdev; 387 struct memory_block *mem; 388 char name[sizeof(MEMORY_CLASS_NAME) + 9 + 1]; 389 390 /* 391 * This only works because we know that section == sysdev->id 392 * slightly redundant with sysdev_register() 393 */ 394 sprintf(&name[0], "%s%d", MEMORY_CLASS_NAME, __section_nr(section)); 395 396 kobj = kset_find_obj(&memory_sysdev_class.kset, name); 397 if (!kobj) 398 return NULL; 399 400 sysdev = container_of(kobj, struct sys_device, kobj); 401 mem = container_of(sysdev, struct memory_block, sysdev); 402 403 return mem; 404 } 405 406 int remove_memory_block(unsigned long node_id, struct mem_section *section, 407 int phys_device) 408 { 409 struct memory_block *mem; 410 411 mem = find_memory_block(section); 412 mem_remove_simple_file(mem, phys_index); 413 mem_remove_simple_file(mem, state); 414 mem_remove_simple_file(mem, phys_device); 415 mem_remove_simple_file(mem, removable); 416 unregister_memory(mem, section); 417 418 return 0; 419 } 420 421 /* 422 * need an interface for the VM to add new memory regions, 423 * but without onlining it. 424 */ 425 int register_new_memory(struct mem_section *section) 426 { 427 return add_memory_block(0, section, MEM_OFFLINE, 0); 428 } 429 430 int unregister_memory_section(struct mem_section *section) 431 { 432 if (!present_section(section)) 433 return -EINVAL; 434 435 return remove_memory_block(0, section, 0); 436 } 437 438 /* 439 * Initialize the sysfs support for memory devices... 440 */ 441 int __init memory_dev_init(void) 442 { 443 unsigned int i; 444 int ret; 445 int err; 446 447 memory_sysdev_class.kset.uevent_ops = &memory_uevent_ops; 448 ret = sysdev_class_register(&memory_sysdev_class); 449 if (ret) 450 goto out; 451 452 /* 453 * Create entries for memory sections that were found 454 * during boot and have been initialized 455 */ 456 for (i = 0; i < NR_MEM_SECTIONS; i++) { 457 if (!present_section_nr(i)) 458 continue; 459 err = add_memory_block(0, __nr_to_section(i), MEM_ONLINE, 0); 460 if (!ret) 461 ret = err; 462 } 463 464 err = memory_probe_init(); 465 if (!ret) 466 ret = err; 467 err = block_size_init(); 468 if (!ret) 469 ret = err; 470 out: 471 if (ret) 472 printk(KERN_ERR "%s() failed: %d\n", __func__, ret); 473 return ret; 474 } 475