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/sched.h> /* capable() */ 17 #include <linux/topology.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 <asm/atomic.h> 24 #include <asm/uaccess.h> 25 26 #define MEMORY_CLASS_NAME "memory" 27 28 static struct sysdev_class memory_sysdev_class = { 29 set_kset_name(MEMORY_CLASS_NAME), 30 }; 31 32 static char *memory_hotplug_name(struct kset *kset, struct kobject *kobj) 33 { 34 return MEMORY_CLASS_NAME; 35 } 36 37 static int memory_hotplug(struct kset *kset, struct kobject *kobj, char **envp, 38 int num_envp, char *buffer, int buffer_size) 39 { 40 int retval = 0; 41 42 return retval; 43 } 44 45 static struct kset_hotplug_ops memory_hotplug_ops = { 46 .name = memory_hotplug_name, 47 .hotplug = memory_hotplug, 48 }; 49 50 static struct notifier_block *memory_chain; 51 52 static int register_memory_notifier(struct notifier_block *nb) 53 { 54 return notifier_chain_register(&memory_chain, nb); 55 } 56 57 static void unregister_memory_notifier(struct notifier_block *nb) 58 { 59 notifier_chain_unregister(&memory_chain, nb); 60 } 61 62 /* 63 * register_memory - Setup a sysfs device for a memory block 64 */ 65 static int 66 register_memory(struct memory_block *memory, struct mem_section *section, 67 struct node *root) 68 { 69 int error; 70 71 memory->sysdev.cls = &memory_sysdev_class; 72 memory->sysdev.id = __section_nr(section); 73 74 error = sysdev_register(&memory->sysdev); 75 76 if (root && !error) 77 error = sysfs_create_link(&root->sysdev.kobj, 78 &memory->sysdev.kobj, 79 kobject_name(&memory->sysdev.kobj)); 80 81 return error; 82 } 83 84 static void 85 unregister_memory(struct memory_block *memory, struct mem_section *section, 86 struct node *root) 87 { 88 BUG_ON(memory->sysdev.cls != &memory_sysdev_class); 89 BUG_ON(memory->sysdev.id != __section_nr(section)); 90 91 sysdev_unregister(&memory->sysdev); 92 if (root) 93 sysfs_remove_link(&root->sysdev.kobj, 94 kobject_name(&memory->sysdev.kobj)); 95 } 96 97 /* 98 * use this as the physical section index that this memsection 99 * uses. 100 */ 101 102 static ssize_t show_mem_phys_index(struct sys_device *dev, char *buf) 103 { 104 struct memory_block *mem = 105 container_of(dev, struct memory_block, sysdev); 106 return sprintf(buf, "%08lx\n", mem->phys_index); 107 } 108 109 /* 110 * online, offline, going offline, etc. 111 */ 112 static ssize_t show_mem_state(struct sys_device *dev, char *buf) 113 { 114 struct memory_block *mem = 115 container_of(dev, struct memory_block, sysdev); 116 ssize_t len = 0; 117 118 /* 119 * We can probably put these states in a nice little array 120 * so that they're not open-coded 121 */ 122 switch (mem->state) { 123 case MEM_ONLINE: 124 len = sprintf(buf, "online\n"); 125 break; 126 case MEM_OFFLINE: 127 len = sprintf(buf, "offline\n"); 128 break; 129 case MEM_GOING_OFFLINE: 130 len = sprintf(buf, "going-offline\n"); 131 break; 132 default: 133 len = sprintf(buf, "ERROR-UNKNOWN-%ld\n", 134 mem->state); 135 WARN_ON(1); 136 break; 137 } 138 139 return len; 140 } 141 142 static inline int memory_notify(unsigned long val, void *v) 143 { 144 return notifier_call_chain(&memory_chain, val, v); 145 } 146 147 /* 148 * MEMORY_HOTPLUG depends on SPARSEMEM in mm/Kconfig, so it is 149 * OK to have direct references to sparsemem variables in here. 150 */ 151 static int 152 memory_block_action(struct memory_block *mem, unsigned long action) 153 { 154 int i; 155 unsigned long psection; 156 unsigned long start_pfn, start_paddr; 157 struct page *first_page; 158 int ret; 159 int old_state = mem->state; 160 161 psection = mem->phys_index; 162 first_page = pfn_to_page(psection << PFN_SECTION_SHIFT); 163 164 /* 165 * The probe routines leave the pages reserved, just 166 * as the bootmem code does. Make sure they're still 167 * that way. 168 */ 169 if (action == MEM_ONLINE) { 170 for (i = 0; i < PAGES_PER_SECTION; i++) { 171 if (PageReserved(first_page+i)) 172 continue; 173 174 printk(KERN_WARNING "section number %ld page number %d " 175 "not reserved, was it already online? \n", 176 psection, i); 177 return -EBUSY; 178 } 179 } 180 181 switch (action) { 182 case MEM_ONLINE: 183 start_pfn = page_to_pfn(first_page); 184 ret = online_pages(start_pfn, PAGES_PER_SECTION); 185 break; 186 case MEM_OFFLINE: 187 mem->state = MEM_GOING_OFFLINE; 188 memory_notify(MEM_GOING_OFFLINE, NULL); 189 start_paddr = page_to_pfn(first_page) << PAGE_SHIFT; 190 ret = remove_memory(start_paddr, 191 PAGES_PER_SECTION << PAGE_SHIFT); 192 if (ret) { 193 mem->state = old_state; 194 break; 195 } 196 memory_notify(MEM_MAPPING_INVALID, NULL); 197 break; 198 default: 199 printk(KERN_WARNING "%s(%p, %ld) unknown action: %ld\n", 200 __FUNCTION__, mem, action, action); 201 WARN_ON(1); 202 ret = -EINVAL; 203 } 204 /* 205 * For now, only notify on successful memory operations 206 */ 207 if (!ret) 208 memory_notify(action, NULL); 209 210 return ret; 211 } 212 213 static int memory_block_change_state(struct memory_block *mem, 214 unsigned long to_state, unsigned long from_state_req) 215 { 216 int ret = 0; 217 down(&mem->state_sem); 218 219 if (mem->state != from_state_req) { 220 ret = -EINVAL; 221 goto out; 222 } 223 224 ret = memory_block_action(mem, to_state); 225 if (!ret) 226 mem->state = to_state; 227 228 out: 229 up(&mem->state_sem); 230 return ret; 231 } 232 233 static ssize_t 234 store_mem_state(struct sys_device *dev, const char *buf, size_t count) 235 { 236 struct memory_block *mem; 237 unsigned int phys_section_nr; 238 int ret = -EINVAL; 239 240 mem = container_of(dev, struct memory_block, sysdev); 241 phys_section_nr = mem->phys_index; 242 243 if (!valid_section_nr(phys_section_nr)) 244 goto out; 245 246 if (!strncmp(buf, "online", min((int)count, 6))) 247 ret = memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE); 248 else if(!strncmp(buf, "offline", min((int)count, 7))) 249 ret = memory_block_change_state(mem, MEM_OFFLINE, MEM_ONLINE); 250 out: 251 if (ret) 252 return ret; 253 return count; 254 } 255 256 /* 257 * phys_device is a bad name for this. What I really want 258 * is a way to differentiate between memory ranges that 259 * are part of physical devices that constitute 260 * a complete removable unit or fru. 261 * i.e. do these ranges belong to the same physical device, 262 * s.t. if I offline all of these sections I can then 263 * remove the physical device? 264 */ 265 static ssize_t show_phys_device(struct sys_device *dev, char *buf) 266 { 267 struct memory_block *mem = 268 container_of(dev, struct memory_block, sysdev); 269 return sprintf(buf, "%d\n", mem->phys_device); 270 } 271 272 static SYSDEV_ATTR(phys_index, 0444, show_mem_phys_index, NULL); 273 static SYSDEV_ATTR(state, 0644, show_mem_state, store_mem_state); 274 static SYSDEV_ATTR(phys_device, 0444, show_phys_device, NULL); 275 276 #define mem_create_simple_file(mem, attr_name) \ 277 sysdev_create_file(&mem->sysdev, &attr_##attr_name) 278 #define mem_remove_simple_file(mem, attr_name) \ 279 sysdev_remove_file(&mem->sysdev, &attr_##attr_name) 280 281 /* 282 * Block size attribute stuff 283 */ 284 static ssize_t 285 print_block_size(struct class *class, char *buf) 286 { 287 return sprintf(buf, "%lx\n", (unsigned long)PAGES_PER_SECTION * PAGE_SIZE); 288 } 289 290 static CLASS_ATTR(block_size_bytes, 0444, print_block_size, NULL); 291 292 static int block_size_init(void) 293 { 294 sysfs_create_file(&memory_sysdev_class.kset.kobj, 295 &class_attr_block_size_bytes.attr); 296 return 0; 297 } 298 299 /* 300 * Some architectures will have custom drivers to do this, and 301 * will not need to do it from userspace. The fake hot-add code 302 * as well as ppc64 will do all of their discovery in userspace 303 * and will require this interface. 304 */ 305 #ifdef CONFIG_ARCH_MEMORY_PROBE 306 static ssize_t 307 memory_probe_store(struct class *class, const char __user *buf, size_t count) 308 { 309 u64 phys_addr; 310 int ret; 311 312 phys_addr = simple_strtoull(buf, NULL, 0); 313 314 ret = add_memory(phys_addr, PAGES_PER_SECTION << PAGE_SHIFT); 315 316 if (ret) 317 count = ret; 318 319 return count; 320 } 321 static CLASS_ATTR(probe, 0700, NULL, memory_probe_store); 322 323 static int memory_probe_init(void) 324 { 325 sysfs_create_file(&memory_sysdev_class.kset.kobj, 326 &class_attr_probe.attr); 327 return 0; 328 } 329 #else 330 #define memory_probe_init(...) do {} while (0) 331 #endif 332 333 /* 334 * Note that phys_device is optional. It is here to allow for 335 * differentiation between which *physical* devices each 336 * section belongs to... 337 */ 338 339 static int add_memory_block(unsigned long node_id, struct mem_section *section, 340 unsigned long state, int phys_device) 341 { 342 struct memory_block *mem = kzalloc(sizeof(*mem), GFP_KERNEL); 343 int ret = 0; 344 345 if (!mem) 346 return -ENOMEM; 347 348 mem->phys_index = __section_nr(section); 349 mem->state = state; 350 init_MUTEX(&mem->state_sem); 351 mem->phys_device = phys_device; 352 353 ret = register_memory(mem, section, NULL); 354 if (!ret) 355 ret = mem_create_simple_file(mem, phys_index); 356 if (!ret) 357 ret = mem_create_simple_file(mem, state); 358 if (!ret) 359 ret = mem_create_simple_file(mem, phys_device); 360 361 return ret; 362 } 363 364 /* 365 * For now, we have a linear search to go find the appropriate 366 * memory_block corresponding to a particular phys_index. If 367 * this gets to be a real problem, we can always use a radix 368 * tree or something here. 369 * 370 * This could be made generic for all sysdev classes. 371 */ 372 static struct memory_block *find_memory_block(struct mem_section *section) 373 { 374 struct kobject *kobj; 375 struct sys_device *sysdev; 376 struct memory_block *mem; 377 char name[sizeof(MEMORY_CLASS_NAME) + 9 + 1]; 378 379 /* 380 * This only works because we know that section == sysdev->id 381 * slightly redundant with sysdev_register() 382 */ 383 sprintf(&name[0], "%s%d", MEMORY_CLASS_NAME, __section_nr(section)); 384 385 kobj = kset_find_obj(&memory_sysdev_class.kset, name); 386 if (!kobj) 387 return NULL; 388 389 sysdev = container_of(kobj, struct sys_device, kobj); 390 mem = container_of(sysdev, struct memory_block, sysdev); 391 392 return mem; 393 } 394 395 int remove_memory_block(unsigned long node_id, struct mem_section *section, 396 int phys_device) 397 { 398 struct memory_block *mem; 399 400 mem = find_memory_block(section); 401 mem_remove_simple_file(mem, phys_index); 402 mem_remove_simple_file(mem, state); 403 mem_remove_simple_file(mem, phys_device); 404 unregister_memory(mem, section, NULL); 405 406 return 0; 407 } 408 409 /* 410 * need an interface for the VM to add new memory regions, 411 * but without onlining it. 412 */ 413 int register_new_memory(struct mem_section *section) 414 { 415 return add_memory_block(0, section, MEM_OFFLINE, 0); 416 } 417 418 int unregister_memory_section(struct mem_section *section) 419 { 420 if (!valid_section(section)) 421 return -EINVAL; 422 423 return remove_memory_block(0, section, 0); 424 } 425 426 /* 427 * Initialize the sysfs support for memory devices... 428 */ 429 int __init memory_dev_init(void) 430 { 431 unsigned int i; 432 int ret; 433 434 memory_sysdev_class.kset.hotplug_ops = &memory_hotplug_ops; 435 ret = sysdev_class_register(&memory_sysdev_class); 436 437 /* 438 * Create entries for memory sections that were found 439 * during boot and have been initialized 440 */ 441 for (i = 0; i < NR_MEM_SECTIONS; i++) { 442 if (!valid_section_nr(i)) 443 continue; 444 add_memory_block(0, __nr_to_section(i), MEM_ONLINE, 0); 445 } 446 447 memory_probe_init(); 448 block_size_init(); 449 450 return ret; 451 } 452