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                 spin_lock(&map_entries_bootmem_lock);
 118                 list_add(&entry->list, &map_entries_bootmem);
 119                 spin_unlock(&map_entries_bootmem_lock);
 120
 121                 return;
 122         }
 123
 124         kfree(entry);
 125 }
 126
 127 static struct kobj_type __refdata memmap_ktype = {
 128         .release        = release_firmware_map_entry,
 129         .sysfs_ops      = &memmap_attr_ops,
 130         .default_attrs  = def_attrs,
 131 };
 132
 133 /*
 134  * Registration functions ------------------------------------------------------
 135  */
 136
 137 /**
 138  * firmware_map_add_entry() - Does the real work to add a firmware memmap entry.
 139  * @start: Start of the memory range.
 140  * @end:   End of the memory range (exclusive).
 141  * @type:  Type of the memory range.
 142  * @entry: Pre-allocated (either kmalloc() or bootmem allocator), uninitialised
 143  *         entry.
 144  *
 145  * Common implementation of firmware_map_add() and firmware_map_add_early()
 146  * which expects a pre-allocated struct firmware_map_entry.
 147  **/
 148 static int firmware_map_add_entry(u64 start, u64 end,
 149                                   const char *type,
 150                                   struct firmware_map_entry *entry)
 151 {
 152         BUG_ON(start > end);
 153
 154         entry->start = start;
 155         entry->end = end - 1;
 156         entry->type = type;
 157         INIT_LIST_HEAD(&entry->list);
 158         kobject_init(&entry->kobj, &memmap_ktype);
 159
 160         spin_lock(&map_entries_lock);
 161         list_add_tail(&entry->list, &map_entries);
 162         spin_unlock(&map_entries_lock);
 163
 164         return 0;
 165 }
 166
 167 /**
 168  * firmware_map_remove_entry() - Does the real work to remove a firmware
 169  * memmap entry.
 170  * @entry: removed entry.
 171  *
 172  * The caller must hold map_entries_lock, and release it properly.
 173  **/
 174 static inline void firmware_map_remove_entry(struct firmware_map_entry *entry)
 175 {
 176         list_del(&entry->list);
 177 }
 178
 179 /*
 180  * Add memmap entry on sysfs
 181  */
 182 static int add_sysfs_fw_map_entry(struct firmware_map_entry *entry)
 183 {
 184         static int map_entries_nr;
 185         static struct kset *mmap_kset;
 186
 187         if (entry->kobj.state_in_sysfs)
 188                 return -EEXIST;
 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(start, end - 1, type);
 293         if (entry)
 294                 return 0;
 295
 296         entry = firmware_map_find_entry_bootmem(start, end - 1, type);
 297         if (!entry) {
 298                 entry = kzalloc(sizeof(struct firmware_map_entry), GFP_ATOMIC);
 299                 if (!entry)
 300                         return -ENOMEM;
 301         } else {
 302                 /* Reuse storage allocated by bootmem. */
 303                 spin_lock(&map_entries_bootmem_lock);
 304                 list_del(&entry->list);
 305                 spin_unlock(&map_entries_bootmem_lock);
 306
 307                 memset(entry, 0, sizeof(*entry));
 308         }
 309
 310         firmware_map_add_entry(start, end, type, entry);
 311         /* create the memmap entry */
 312         add_sysfs_fw_map_entry(entry);
 313
 314         return 0;
 315 }
 316
 317 /**
 318  * firmware_map_add_early() - Adds a firmware mapping entry.
 319  * @start: Start of the memory range.
 320  * @end:   End of the memory range.
 321  * @type:  Type of the memory range.
 322  *
 323  * Adds a firmware mapping entry. This function uses the bootmem allocator
 324  * for memory allocation.
 325  *
 326  * That function must be called before late_initcall.
 327  *
 328  * Returns 0 on success, or -ENOMEM if no memory could be allocated.
 329  **/
 330 int __init firmware_map_add_early(u64 start, u64 end, const char *type)
 331 {
 332         struct firmware_map_entry *entry;
 333
 334         entry = memblock_virt_alloc(sizeof(struct firmware_map_entry), 0);
 335         if (WARN_ON(!entry))
 336                 return -ENOMEM;
 337
 338         return firmware_map_add_entry(start, end, type, entry);
 339 }
 340
 341 /**
 342  * firmware_map_remove() - remove a firmware mapping entry
 343  * @start: Start of the memory range.
 344  * @end:   End of the memory range.
 345  * @type:  Type of the memory range.
 346  *
 347  * removes a firmware mapping entry.
 348  *
 349  * Returns 0 on success, or -EINVAL if no entry.
 350  **/
 351 int __meminit firmware_map_remove(u64 start, u64 end, const char *type)
 352 {
 353         struct firmware_map_entry *entry;
 354
 355         spin_lock(&map_entries_lock);
 356         entry = firmware_map_find_entry(start, end - 1, type);
 357         if (!entry) {
 358                 spin_unlock(&map_entries_lock);
 359                 return -EINVAL;
 360         }
 361
 362         firmware_map_remove_entry(entry);
 363         spin_unlock(&map_entries_lock);
 364
 365         /* remove the memmap entry */
 366         remove_sysfs_fw_map_entry(entry);
 367
 368         return 0;
 369 }
 370
 371 /*
 372  * Sysfs functions -------------------------------------------------------------
 373  */
 374
 375 static ssize_t start_show(struct firmware_map_entry *entry, char *buf)
 376 {
 377         return snprintf(buf, PAGE_SIZE, "0x%llx\n",
 378                 (unsigned long long)entry->start);
 379 }
 380
 381 static ssize_t end_show(struct firmware_map_entry *entry, char *buf)
 382 {
 383         return snprintf(buf, PAGE_SIZE, "0x%llx\n",
 384                 (unsigned long long)entry->end);
 385 }
 386
 387 static ssize_t type_show(struct firmware_map_entry *entry, char *buf)
 388 {
 389         return snprintf(buf, PAGE_SIZE, "%s\n", entry->type);
 390 }
 391
 392 static inline struct memmap_attribute *to_memmap_attr(struct attribute *attr)
 393 {
 394         return container_of(attr, struct memmap_attribute, attr);
 395 }
 396
 397 static ssize_t memmap_attr_show(struct kobject *kobj,
 398                                 struct attribute *attr, char *buf)
 399 {
 400         struct firmware_map_entry *entry = to_memmap_entry(kobj);
 401         struct memmap_attribute *memmap_attr = to_memmap_attr(attr);
 402
 403         return memmap_attr->show(entry, buf);
 404 }
 405
 406 /*
 407  * Initialises stuff and adds the entries in the map_entries list to
 408  * sysfs. Important is that firmware_map_add() and firmware_map_add_early()
 409  * must be called before late_initcall. That's just because that function
 410  * is called as late_initcall() function, which means that if you call
 411  * firmware_map_add() or firmware_map_add_early() afterwards, the entries
 412  * are not added to sysfs.
 413  */
 414 static int __init firmware_memmap_init(void)
 415 {
 416         struct firmware_map_entry *entry;
 417
 418         list_for_each_entry(entry, &map_entries, list)
 419                 add_sysfs_fw_map_entry(entry);
 420
 421         return 0;
 422 }
 423 late_initcall(firmware_memmap_init);
 424