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