drivers/firmware/memmap.c

   1 /*
   2  * linux/drivers/firmware/memmap.c
   3  *  Copyright (C) 2008 SUSE LINUX Products GmbH
   4  *  by Bernhard Walle <bernhard.walle@gmx.de>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License v2.0 as published by
   8  * the Free Software Foundation
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  */
  16
  17 #include <linux/string.h>
  18 #include <linux/firmware-map.h>
  19 #include <linux/kernel.h>
  20 #include <linux/module.h>
  21 #include <linux/types.h>
  22 #include <linux/bootmem.h>
  23 #include <linux/slab.h>
  24 #include <linux/mm.h>
  25
  26 /*
  27  * Data types ------------------------------------------------------------------
  28  */
  29
  30 /*
  31  * Firmware map entry. Because firmware memory maps are flat and not
  32  * hierarchical, it's ok to organise them in a linked list. No parent
  33  * information is necessary as for the resource tree.
  34  */
  35 struct firmware_map_entry {
  36         /*
  37          * start and end must be u64 rather than resource_size_t, because e820
  38          * resources can lie at addresses above 4G.
  39          */
  40         u64                     start;  /* start of the memory range */
  41         u64                     end;    /* end of the memory range (incl.) */
  42         const char              *type;  /* type of the memory range */
  43         struct list_head        list;   /* entry for the linked list */
  44         struct kobject          kobj;   /* kobject for each entry */
  45 };
  46
  47 /*
  48  * Forward declarations --------------------------------------------------------
  49  */
  50 static ssize_t memmap_attr_show(struct kobject *kobj,
  51                                 struct attribute *attr, char *buf);
  52 static ssize_t start_show(struct firmware_map_entry *entry, char *buf);
  53 static ssize_t end_show(struct firmware_map_entry *entry, char *buf);
  54 static ssize_t type_show(struct firmware_map_entry *entry, char *buf);
  55
  56 static struct firmware_map_entry * __meminit
  57 firmware_map_find_entry(u64 start, u64 end, const char *type);
  58
  59 /*
  60  * Static data -----------------------------------------------------------------
  61  */
  62
  63 struct memmap_attribute {
  64         struct attribute attr;
  65         ssize_t (*show)(struct firmware_map_entry *entry, char *buf);
  66 };
  67
  68 static struct memmap_attribute memmap_start_attr = __ATTR_RO(start);
  69 static struct memmap_attribute memmap_end_attr   = __ATTR_RO(end);
  70 static struct memmap_attribute memmap_type_attr  = __ATTR_RO(type);
  71
  72 /*
  73  * These are default attributes that are added for every memmap entry.
  74  */
  75 static struct attribute *def_attrs[] = {
  76         &memmap_start_attr.attr,
  77         &memmap_end_attr.attr,
  78         &memmap_type_attr.attr,
  79         NULL
  80 };
  81
  82 static const struct sysfs_ops memmap_attr_ops = {
  83         .show = memmap_attr_show,
  84 };
  85
  86 /* Firmware memory map entries. */
  87 static LIST_HEAD(map_entries);
  88 static DEFINE_SPINLOCK(map_entries_lock);
  89
  90 /*
  91  * For memory hotplug, there is no way to free memory map entries allocated
  92  * by boot mem after the system is up. So when we hot-remove memory whose
  93  * map entry is allocated by bootmem, we need to remember the storage and
  94  * reuse it when the memory is hot-added again.
  95  */
  96 static LIST_HEAD(map_entries_bootmem);
  97 static DEFINE_SPINLOCK(map_entries_bootmem_lock);
  98
  99
 100 static inline struct firmware_map_entry *
 101 to_memmap_entry(struct kobject *kobj)
 102 {
 103         return container_of(kobj, struct firmware_map_entry, kobj);
 104 }
 105
 106 static void __meminit release_firmware_map_entry(struct kobject *kobj)
 107 {
 108         struct firmware_map_entry *entry = to_memmap_entry(kobj);
 109
 110         if (PageReserved(virt_to_page(entry))) {
 111                 /*
 112                  * Remember the storage allocated by bootmem, and reuse it when
 113                  * the memory is hot-added again. The entry will be added to
 114                  * map_entries_bootmem here, and deleted from &map_entries in
 115                  * firmware_map_remove_entry().
 116                  */
 117                 if (firmware_map_find_entry(entry->start, entry->end,
 118                     entry->type)) {
 119                         spin_lock(&map_entries_bootmem_lock);
 120                         list_add(&entry->list, &map_entries_bootmem);
 121                         spin_unlock(&map_entries_bootmem_lock);
 122                 }
 123
 124                 return;
 125         }
 126
 127         kfree(entry);
 128 }
 129
 130 static struct kobj_type __refdata memmap_ktype = {
 131         .release        = release_firmware_map_entry,
 132         .sysfs_ops      = &memmap_attr_ops,
 133         .default_attrs  = def_attrs,
 134 };
 135
 136 /*
 137  * Registration functions ------------------------------------------------------
 138  */
 139
 140 /**
 141  * firmware_map_add_entry() - Does the real work to add a firmware memmap entry.
 142  * @start: Start of the memory range.
 143  * @end:   End of the memory range (exclusive).
 144  * @type:  Type of the memory range.
 145  * @entry: Pre-allocated (either kmalloc() or bootmem allocator), uninitialised
 146  *         entry.
 147  *
 148  * Common implementation of firmware_map_add() and firmware_map_add_early()
 149  * which expects a pre-allocated struct firmware_map_entry.
 150  **/
 151 static int firmware_map_add_entry(u64 start, u64 end,
 152                                   const char *type,
 153                                   struct firmware_map_entry *entry)
 154 {
 155         BUG_ON(start > end);
 156
 157         entry->start = start;
 158         entry->end = end - 1;
 159         entry->type = type;
 160         INIT_LIST_HEAD(&entry->list);
 161         kobject_init(&entry->kobj, &memmap_ktype);
 162
 163         spin_lock(&map_entries_lock);
 164         list_add_tail(&entry->list, &map_entries);
 165         spin_unlock(&map_entries_lock);
 166
 167         return 0;
 168 }
 169
 170 /**
 171  * firmware_map_remove_entry() - Does the real work to remove a firmware
 172  * memmap entry.
 173  * @entry: removed entry.
 174  *
 175  * The caller must hold map_entries_lock, and release it properly.
 176  **/
 177 static inline void firmware_map_remove_entry(struct firmware_map_entry *entry)
 178 {
 179         list_del(&entry->list);
 180 }
 181
 182 /*
 183  * Add memmap entry on sysfs
 184  */
 185 static int add_sysfs_fw_map_entry(struct firmware_map_entry *entry)
 186 {
 187         static int map_entries_nr;
 188         static struct kset *mmap_kset;
 189
 190         if (!mmap_kset) {
 191                 mmap_kset = kset_create_and_add("memmap", NULL, firmware_kobj);
 192                 if (!mmap_kset)
 193                         return -ENOMEM;
 194         }
 195
 196         entry->kobj.kset = mmap_kset;
 197         if (kobject_add(&entry->kobj, NULL, "%d", map_entries_nr++))
 198                 kobject_put(&entry->kobj);
 199
 200         return 0;
 201 }
 202
 203 /*
 204  * Remove memmap entry on sysfs
 205  */
 206 static inline void remove_sysfs_fw_map_entry(struct firmware_map_entry *entry)
 207 {
 208         kobject_put(&entry->kobj);
 209 }
 210
 211 /*
 212  * firmware_map_find_entry_in_list() - Search memmap entry in a given list.
 213  * @start: Start of the memory range.
 214  * @end:   End of the memory range (exclusive).
 215  * @type:  Type of the memory range.
 216  * @list:  In which to find the entry.
 217  *
 218  * This function is to find the memmap entey of a given memory range in a
 219  * given list. The caller must hold map_entries_lock, and must not release
 220  * the lock until the processing of the returned entry has completed.
 221  *
 222  * Return: Pointer to the entry to be found on success, or NULL on failure.
 223  */
 224 static struct firmware_map_entry * __meminit
 225 firmware_map_find_entry_in_list(u64 start, u64 end, const char *type,
 226                                 struct list_head *list)
 227 {
 228         struct firmware_map_entry *entry;
 229
 230         list_for_each_entry(entry, list, list)
 231                 if ((entry->start == start) && (entry->end == end) &&
 232                     (!strcmp(entry->type, type))) {
 233                         return entry;
 234                 }
 235
 236         return NULL;
 237 }
 238
 239 /*
 240  * firmware_map_find_entry() - Search memmap entry in map_entries.
 241  * @start: Start of the memory range.
 242  * @end:   End of the memory range (exclusive).
 243  * @type:  Type of the memory range.
 244  *
 245  * This function is to find the memmap entey of a given memory range.
 246  * The caller must hold map_entries_lock, and must not release the lock
 247  * until the processing of the returned entry has completed.
 248  *
 249  * Return: Pointer to the entry to be found on success, or NULL on failure.
 250  */
 251 static struct firmware_map_entry * __meminit
 252 firmware_map_find_entry(u64 start, u64 end, const char *type)
 253 {
 254         return firmware_map_find_entry_in_list(start, end, type, &map_entries);
 255 }
 256
 257 /*
 258  * firmware_map_find_entry_bootmem() - Search memmap entry in map_entries_bootmem.
 259  * @start: Start of the memory range.
 260  * @end:   End of the memory range (exclusive).
 261  * @type:  Type of the memory range.
 262  *
 263  * This function is similar to firmware_map_find_entry except that it find the
 264  * given entry in map_entries_bootmem.
 265  *
 266  * Return: Pointer to the entry to be found on success, or NULL on failure.
 267  */
 268 static struct firmware_map_entry * __meminit
 269 firmware_map_find_entry_bootmem(u64 start, u64 end, const char *type)
 270 {
 271         return firmware_map_find_entry_in_list(start, end, type,
 272                                                &map_entries_bootmem);
 273 }
 274
 275 /**
 276  * firmware_map_add_hotplug() - Adds a firmware mapping entry when we do
 277  * memory hotplug.
 278  * @start: Start of the memory range.
 279  * @end:   End of the memory range (exclusive)
 280  * @type:  Type of the memory range.
 281  *
 282  * Adds a firmware mapping entry. This function is for memory hotplug, it is
 283  * similar to function firmware_map_add_early(). The only difference is that
 284  * it will create the syfs entry dynamically.
 285  *
 286  * Returns 0 on success, or -ENOMEM if no memory could be allocated.
 287  **/
 288 int __meminit firmware_map_add_hotplug(u64 start, u64 end, const char *type)
 289 {
 290         struct firmware_map_entry *entry;
 291
 292         entry = firmware_map_find_entry_bootmem(start, end, type);
 293         if (!entry) {
 294                 entry = kzalloc(sizeof(struct firmware_map_entry), GFP_ATOMIC);
 295                 if (!entry)
 296                         return -ENOMEM;
 297         } else {
 298                 /* Reuse storage allocated by bootmem. */
 299                 spin_lock(&map_entries_bootmem_lock);
 300                 list_del(&entry->list);
 301                 spin_unlock(&map_entries_bootmem_lock);
 302
 303                 memset(entry, 0, sizeof(*entry));
 304         }
 305
 306         firmware_map_add_entry(start, end, type, entry);
 307         /* create the memmap entry */
 308         add_sysfs_fw_map_entry(entry);
 309
 310         return 0;
 311 }
 312
 313 /**
 314  * firmware_map_add_early() - Adds a firmware mapping entry.
 315  * @start: Start of the memory range.
 316  * @end:   End of the memory range.
 317  * @type:  Type of the memory range.
 318  *
 319  * Adds a firmware mapping entry. This function uses the bootmem allocator
 320  * for memory allocation.
 321  *
 322  * That function must be called before late_initcall.
 323  *
 324  * Returns 0 on success, or -ENOMEM if no memory could be allocated.
 325  **/
 326 int __init firmware_map_add_early(u64 start, u64 end, const char *type)
 327 {
 328         struct firmware_map_entry *entry;
 329
 330         entry = alloc_bootmem(sizeof(struct firmware_map_entry));
 331         if (WARN_ON(!entry))
 332                 return -ENOMEM;
 333
 334         return firmware_map_add_entry(start, end, type, entry);
 335 }
 336
 337 /**
 338  * firmware_map_remove() - remove a firmware mapping entry
 339  * @start: Start of the memory range.
 340  * @end:   End of the memory range.
 341  * @type:  Type of the memory range.
 342  *
 343  * removes a firmware mapping entry.
 344  *
 345  * Returns 0 on success, or -EINVAL if no entry.
 346  **/
 347 int __meminit firmware_map_remove(u64 start, u64 end, const char *type)
 348 {
 349         struct firmware_map_entry *entry;
 350
 351         spin_lock(&map_entries_lock);
 352         entry = firmware_map_find_entry(start, end - 1, type);
 353         if (!entry) {
 354                 spin_unlock(&map_entries_lock);
 355                 return -EINVAL;
 356         }
 357
 358         firmware_map_remove_entry(entry);
 359         spin_unlock(&map_entries_lock);
 360
 361         /* remove the memmap entry */
 362         remove_sysfs_fw_map_entry(entry);
 363
 364         return 0;
 365 }
 366
 367 /*
 368  * Sysfs functions -------------------------------------------------------------
 369  */
 370
 371 static ssize_t start_show(struct firmware_map_entry *entry, char *buf)
 372 {
 373         return snprintf(buf, PAGE_SIZE, "0x%llx\n",
 374                 (unsigned long long)entry->start);
 375 }
 376
 377 static ssize_t end_show(struct firmware_map_entry *entry, char *buf)
 378 {
 379         return snprintf(buf, PAGE_SIZE, "0x%llx\n",
 380                 (unsigned long long)entry->end);
 381 }
 382
 383 static ssize_t type_show(struct firmware_map_entry *entry, char *buf)
 384 {
 385         return snprintf(buf, PAGE_SIZE, "%s\n", entry->type);
 386 }
 387
 388 static inline struct memmap_attribute *to_memmap_attr(struct attribute *attr)
 389 {
 390         return container_of(attr, struct memmap_attribute, attr);
 391 }
 392
 393 static ssize_t memmap_attr_show(struct kobject *kobj,
 394                                 struct attribute *attr, char *buf)
 395 {
 396         struct firmware_map_entry *entry = to_memmap_entry(kobj);
 397         struct memmap_attribute *memmap_attr = to_memmap_attr(attr);
 398
 399         return memmap_attr->show(entry, buf);
 400 }
 401
 402 /*
 403  * Initialises stuff and adds the entries in the map_entries list to
 404  * sysfs. Important is that firmware_map_add() and firmware_map_add_early()
 405  * must be called before late_initcall. That's just because that function
 406  * is called as late_initcall() function, which means that if you call
 407  * firmware_map_add() or firmware_map_add_early() afterwards, the entries
 408  * are not added to sysfs.
 409  */
 410 static int __init firmware_memmap_init(void)
 411 {
 412         struct firmware_map_entry *entry;
 413
 414         list_for_each_entry(entry, &map_entries, list)
 415                 add_sysfs_fw_map_entry(entry);
 416
 417         return 0;
 418 }
 419 late_initcall(firmware_memmap_init);
 420