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 (!mmap_kset) {
 188                 mmap_kset = kset_create_and_add("memmap", NULL, firmware_kobj);
 189                 if (!mmap_kset)
 190                         return -ENOMEM;
 191         }
 192
 193         entry->kobj.kset = mmap_kset;
 194         if (kobject_add(&entry->kobj, NULL, "%d", map_entries_nr++))
 195                 kobject_put(&entry->kobj);
 196
 197         return 0;
 198 }
 199
 200 /*
 201  * Remove memmap entry on sysfs
 202  */
 203 static inline void remove_sysfs_fw_map_entry(struct firmware_map_entry *entry)
 204 {
 205         kobject_put(&entry->kobj);
 206 }
 207
 208 /*
 209  * firmware_map_find_entry_in_list() - Search memmap entry in a given list.
 210  * @start: Start of the memory range.
 211  * @end:   End of the memory range (exclusive).
 212  * @type:  Type of the memory range.
 213  * @list:  In which to find the entry.
 214  *
 215  * This function is to find the memmap entey of a given memory range in a
 216  * given list. The caller must hold map_entries_lock, and must not release
 217  * the lock until the processing of the returned entry has completed.
 218  *
 219  * Return: Pointer to the entry to be found on success, or NULL on failure.
 220  */
 221 static struct firmware_map_entry * __meminit
 222 firmware_map_find_entry_in_list(u64 start, u64 end, const char *type,
 223                                 struct list_head *list)
 224 {
 225         struct firmware_map_entry *entry;
 226
 227         list_for_each_entry(entry, list, list)
 228                 if ((entry->start == start) && (entry->end == end) &&
 229                     (!strcmp(entry->type, type))) {
 230                         return entry;
 231                 }
 232
 233         return NULL;
 234 }
 235
 236 /*
 237  * firmware_map_find_entry() - Search memmap entry in map_entries.
 238  * @start: Start of the memory range.
 239  * @end:   End of the memory range (exclusive).
 240  * @type:  Type of the memory range.
 241  *
 242  * This function is to find the memmap entey of a given memory range.
 243  * The caller must hold map_entries_lock, and must not release the lock
 244  * until the processing of the returned entry has completed.
 245  *
 246  * Return: Pointer to the entry to be found on success, or NULL on failure.
 247  */
 248 static struct firmware_map_entry * __meminit
 249 firmware_map_find_entry(u64 start, u64 end, const char *type)
 250 {
 251         return firmware_map_find_entry_in_list(start, end, type, &map_entries);
 252 }
 253
 254 /*
 255  * firmware_map_find_entry_bootmem() - Search memmap entry in map_entries_bootmem.
 256  * @start: Start of the memory range.
 257  * @end:   End of the memory range (exclusive).
 258  * @type:  Type of the memory range.
 259  *
 260  * This function is similar to firmware_map_find_entry except that it find the
 261  * given entry in map_entries_bootmem.
 262  *
 263  * Return: Pointer to the entry to be found on success, or NULL on failure.
 264  */
 265 static struct firmware_map_entry * __meminit
 266 firmware_map_find_entry_bootmem(u64 start, u64 end, const char *type)
 267 {
 268         return firmware_map_find_entry_in_list(start, end, type,
 269                                                &map_entries_bootmem);
 270 }
 271
 272 /**
 273  * firmware_map_add_hotplug() - Adds a firmware mapping entry when we do
 274  * memory hotplug.
 275  * @start: Start of the memory range.
 276  * @end:   End of the memory range (exclusive)
 277  * @type:  Type of the memory range.
 278  *
 279  * Adds a firmware mapping entry. This function is for memory hotplug, it is
 280  * similar to function firmware_map_add_early(). The only difference is that
 281  * it will create the syfs entry dynamically.
 282  *
 283  * Returns 0 on success, or -ENOMEM if no memory could be allocated.
 284  **/
 285 int __meminit firmware_map_add_hotplug(u64 start, u64 end, const char *type)
 286 {
 287         struct firmware_map_entry *entry;
 288
 289         entry = firmware_map_find_entry_bootmem(start, end, type);
 290         if (!entry) {
 291                 entry = kzalloc(sizeof(struct firmware_map_entry), GFP_ATOMIC);
 292                 if (!entry)
 293                         return -ENOMEM;
 294         } else {
 295                 /* Reuse storage allocated by bootmem. */
 296                 spin_lock(&map_entries_bootmem_lock);
 297                 list_del(&entry->list);
 298                 spin_unlock(&map_entries_bootmem_lock);
 299
 300                 memset(entry, 0, sizeof(*entry));
 301         }
 302
 303         firmware_map_add_entry(start, end, type, entry);
 304         /* create the memmap entry */
 305         add_sysfs_fw_map_entry(entry);
 306
 307         return 0;
 308 }
 309
 310 /**
 311  * firmware_map_add_early() - Adds a firmware mapping entry.
 312  * @start: Start of the memory range.
 313  * @end:   End of the memory range.
 314  * @type:  Type of the memory range.
 315  *
 316  * Adds a firmware mapping entry. This function uses the bootmem allocator
 317  * for memory allocation.
 318  *
 319  * That function must be called before late_initcall.
 320  *
 321  * Returns 0 on success, or -ENOMEM if no memory could be allocated.
 322  **/
 323 int __init firmware_map_add_early(u64 start, u64 end, const char *type)
 324 {
 325         struct firmware_map_entry *entry;
 326
 327         entry = alloc_bootmem(sizeof(struct firmware_map_entry));
 328         if (WARN_ON(!entry))
 329                 return -ENOMEM;
 330
 331         return firmware_map_add_entry(start, end, type, entry);
 332 }
 333
 334 /**
 335  * firmware_map_remove() - remove a firmware mapping entry
 336  * @start: Start of the memory range.
 337  * @end:   End of the memory range.
 338  * @type:  Type of the memory range.
 339  *
 340  * removes a firmware mapping entry.
 341  *
 342  * Returns 0 on success, or -EINVAL if no entry.
 343  **/
 344 int __meminit firmware_map_remove(u64 start, u64 end, const char *type)
 345 {
 346         struct firmware_map_entry *entry;
 347
 348         spin_lock(&map_entries_lock);
 349         entry = firmware_map_find_entry(start, end - 1, type);
 350         if (!entry) {
 351                 spin_unlock(&map_entries_lock);
 352                 return -EINVAL;
 353         }
 354
 355         firmware_map_remove_entry(entry);
 356         spin_unlock(&map_entries_lock);
 357
 358         /* remove the memmap entry */
 359         remove_sysfs_fw_map_entry(entry);
 360
 361         return 0;
 362 }
 363
 364 /*
 365  * Sysfs functions -------------------------------------------------------------
 366  */
 367
 368 static ssize_t start_show(struct firmware_map_entry *entry, char *buf)
 369 {
 370         return snprintf(buf, PAGE_SIZE, "0x%llx\n",
 371                 (unsigned long long)entry->start);
 372 }
 373
 374 static ssize_t end_show(struct firmware_map_entry *entry, char *buf)
 375 {
 376         return snprintf(buf, PAGE_SIZE, "0x%llx\n",
 377                 (unsigned long long)entry->end);
 378 }
 379
 380 static ssize_t type_show(struct firmware_map_entry *entry, char *buf)
 381 {
 382         return snprintf(buf, PAGE_SIZE, "%s\n", entry->type);
 383 }
 384
 385 static inline struct memmap_attribute *to_memmap_attr(struct attribute *attr)
 386 {
 387         return container_of(attr, struct memmap_attribute, attr);
 388 }
 389
 390 static ssize_t memmap_attr_show(struct kobject *kobj,
 391                                 struct attribute *attr, char *buf)
 392 {
 393         struct firmware_map_entry *entry = to_memmap_entry(kobj);
 394         struct memmap_attribute *memmap_attr = to_memmap_attr(attr);
 395
 396         return memmap_attr->show(entry, buf);
 397 }
 398
 399 /*
 400  * Initialises stuff and adds the entries in the map_entries list to
 401  * sysfs. Important is that firmware_map_add() and firmware_map_add_early()
 402  * must be called before late_initcall. That's just because that function
 403  * is called as late_initcall() function, which means that if you call
 404  * firmware_map_add() or firmware_map_add_early() afterwards, the entries
 405  * are not added to sysfs.
 406  */
 407 static int __init firmware_memmap_init(void)
 408 {
 409         struct firmware_map_entry *entry;
 410
 411         list_for_each_entry(entry, &map_entries, list)
 412                 add_sysfs_fw_map_entry(entry);
 413
 414         return 0;
 415 }
 416 late_initcall(firmware_memmap_init);
 417