1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * linux/drivers/firmware/memmap.c |
4 | * Copyright (C) 2008 SUSE LINUX Products GmbH |
5 | * by Bernhard Walle <bernhard.walle@gmx.de> |
6 | */ |
7 | |
8 | #include <linux/string.h> |
9 | #include <linux/firmware-map.h> |
10 | #include <linux/kernel.h> |
11 | #include <linux/module.h> |
12 | #include <linux/types.h> |
13 | #include <linux/memblock.h> |
14 | #include <linux/slab.h> |
15 | #include <linux/mm.h> |
16 | |
17 | /* |
18 | * Data types ------------------------------------------------------------------ |
19 | */ |
20 | |
21 | /* |
22 | * Firmware map entry. Because firmware memory maps are flat and not |
23 | * hierarchical, it's ok to organise them in a linked list. No parent |
24 | * information is necessary as for the resource tree. |
25 | */ |
26 | struct firmware_map_entry { |
27 | /* |
28 | * start and end must be u64 rather than resource_size_t, because e820 |
29 | * resources can lie at addresses above 4G. |
30 | */ |
31 | u64 start; /* start of the memory range */ |
32 | u64 end; /* end of the memory range (incl.) */ |
33 | const char *type; /* type of the memory range */ |
34 | struct list_head list; /* entry for the linked list */ |
35 | struct kobject kobj; /* kobject for each entry */ |
36 | }; |
37 | |
38 | /* |
39 | * Forward declarations -------------------------------------------------------- |
40 | */ |
41 | static ssize_t memmap_attr_show(struct kobject *kobj, |
42 | struct attribute *attr, char *buf); |
43 | static ssize_t start_show(struct firmware_map_entry *entry, char *buf); |
44 | static ssize_t end_show(struct firmware_map_entry *entry, char *buf); |
45 | static ssize_t type_show(struct firmware_map_entry *entry, char *buf); |
46 | |
47 | static struct firmware_map_entry * __meminit |
48 | firmware_map_find_entry(u64 start, u64 end, const char *type); |
49 | |
50 | /* |
51 | * Static data ----------------------------------------------------------------- |
52 | */ |
53 | |
54 | struct memmap_attribute { |
55 | struct attribute attr; |
56 | ssize_t (*show)(struct firmware_map_entry *entry, char *buf); |
57 | }; |
58 | |
59 | static struct memmap_attribute memmap_start_attr = __ATTR_RO(start); |
60 | static struct memmap_attribute memmap_end_attr = __ATTR_RO(end); |
61 | static struct memmap_attribute memmap_type_attr = __ATTR_RO(type); |
62 | |
63 | /* |
64 | * These are default attributes that are added for every memmap entry. |
65 | */ |
66 | static struct attribute *def_attrs[] = { |
67 | &memmap_start_attr.attr, |
68 | &memmap_end_attr.attr, |
69 | &memmap_type_attr.attr, |
70 | NULL |
71 | }; |
72 | ATTRIBUTE_GROUPS(def); |
73 | |
74 | static const struct sysfs_ops memmap_attr_ops = { |
75 | .show = memmap_attr_show, |
76 | }; |
77 | |
78 | /* Firmware memory map entries. */ |
79 | static LIST_HEAD(map_entries); |
80 | static DEFINE_SPINLOCK(map_entries_lock); |
81 | |
82 | /* |
83 | * For memory hotplug, there is no way to free memory map entries allocated |
84 | * by boot mem after the system is up. So when we hot-remove memory whose |
85 | * map entry is allocated by bootmem, we need to remember the storage and |
86 | * reuse it when the memory is hot-added again. |
87 | */ |
88 | static LIST_HEAD(map_entries_bootmem); |
89 | static DEFINE_SPINLOCK(map_entries_bootmem_lock); |
90 | |
91 | |
92 | static inline struct firmware_map_entry * |
93 | to_memmap_entry(struct kobject *kobj) |
94 | { |
95 | return container_of(kobj, struct firmware_map_entry, kobj); |
96 | } |
97 | |
98 | static void __meminit release_firmware_map_entry(struct kobject *kobj) |
99 | { |
100 | struct firmware_map_entry *entry = to_memmap_entry(kobj); |
101 | |
102 | if (PageReserved(virt_to_page(entry))) { |
103 | /* |
104 | * Remember the storage allocated by bootmem, and reuse it when |
105 | * the memory is hot-added again. The entry will be added to |
106 | * map_entries_bootmem here, and deleted from &map_entries in |
107 | * firmware_map_remove_entry(). |
108 | */ |
109 | spin_lock(lock: &map_entries_bootmem_lock); |
110 | list_add(new: &entry->list, head: &map_entries_bootmem); |
111 | spin_unlock(lock: &map_entries_bootmem_lock); |
112 | |
113 | return; |
114 | } |
115 | |
116 | kfree(objp: entry); |
117 | } |
118 | |
119 | static struct kobj_type __refdata memmap_ktype = { |
120 | .release = release_firmware_map_entry, |
121 | .sysfs_ops = &memmap_attr_ops, |
122 | .default_groups = def_groups, |
123 | }; |
124 | |
125 | /* |
126 | * Registration functions ------------------------------------------------------ |
127 | */ |
128 | |
129 | /** |
130 | * firmware_map_add_entry() - Does the real work to add a firmware memmap entry. |
131 | * @start: Start of the memory range. |
132 | * @end: End of the memory range (exclusive). |
133 | * @type: Type of the memory range. |
134 | * @entry: Pre-allocated (either kmalloc() or bootmem allocator), uninitialised |
135 | * entry. |
136 | * |
137 | * Common implementation of firmware_map_add() and firmware_map_add_early() |
138 | * which expects a pre-allocated struct firmware_map_entry. |
139 | * |
140 | * Return: 0 always |
141 | */ |
142 | static int firmware_map_add_entry(u64 start, u64 end, |
143 | const char *type, |
144 | struct firmware_map_entry *entry) |
145 | { |
146 | BUG_ON(start > end); |
147 | |
148 | entry->start = start; |
149 | entry->end = end - 1; |
150 | entry->type = type; |
151 | INIT_LIST_HEAD(list: &entry->list); |
152 | kobject_init(kobj: &entry->kobj, ktype: &memmap_ktype); |
153 | |
154 | spin_lock(lock: &map_entries_lock); |
155 | list_add_tail(new: &entry->list, head: &map_entries); |
156 | spin_unlock(lock: &map_entries_lock); |
157 | |
158 | return 0; |
159 | } |
160 | |
161 | /** |
162 | * firmware_map_remove_entry() - Does the real work to remove a firmware |
163 | * memmap entry. |
164 | * @entry: removed entry. |
165 | * |
166 | * The caller must hold map_entries_lock, and release it properly. |
167 | */ |
168 | static inline void firmware_map_remove_entry(struct firmware_map_entry *entry) |
169 | { |
170 | list_del(entry: &entry->list); |
171 | } |
172 | |
173 | /* |
174 | * Add memmap entry on sysfs |
175 | */ |
176 | static int add_sysfs_fw_map_entry(struct firmware_map_entry *entry) |
177 | { |
178 | static int map_entries_nr; |
179 | static struct kset *mmap_kset; |
180 | |
181 | if (entry->kobj.state_in_sysfs) |
182 | return -EEXIST; |
183 | |
184 | if (!mmap_kset) { |
185 | mmap_kset = kset_create_and_add(name: "memmap" , NULL, parent_kobj: firmware_kobj); |
186 | if (!mmap_kset) |
187 | return -ENOMEM; |
188 | } |
189 | |
190 | entry->kobj.kset = mmap_kset; |
191 | if (kobject_add(kobj: &entry->kobj, NULL, fmt: "%d" , map_entries_nr++)) |
192 | kobject_put(kobj: &entry->kobj); |
193 | |
194 | return 0; |
195 | } |
196 | |
197 | /* |
198 | * Remove memmap entry on sysfs |
199 | */ |
200 | static inline void remove_sysfs_fw_map_entry(struct firmware_map_entry *entry) |
201 | { |
202 | kobject_put(kobj: &entry->kobj); |
203 | } |
204 | |
205 | /** |
206 | * firmware_map_find_entry_in_list() - Search memmap entry in a given list. |
207 | * @start: Start of the memory range. |
208 | * @end: End of the memory range (exclusive). |
209 | * @type: Type of the memory range. |
210 | * @list: In which to find the entry. |
211 | * |
212 | * This function is to find the memmap entey of a given memory range in a |
213 | * given list. The caller must hold map_entries_lock, and must not release |
214 | * the lock until the processing of the returned entry has completed. |
215 | * |
216 | * Return: Pointer to the entry to be found on success, or NULL on failure. |
217 | */ |
218 | static struct firmware_map_entry * __meminit |
219 | firmware_map_find_entry_in_list(u64 start, u64 end, const char *type, |
220 | struct list_head *list) |
221 | { |
222 | struct firmware_map_entry *entry; |
223 | |
224 | list_for_each_entry(entry, list, list) |
225 | if ((entry->start == start) && (entry->end == end) && |
226 | (!strcmp(entry->type, type))) { |
227 | return entry; |
228 | } |
229 | |
230 | return NULL; |
231 | } |
232 | |
233 | /** |
234 | * firmware_map_find_entry() - Search memmap entry in map_entries. |
235 | * @start: Start of the memory range. |
236 | * @end: End of the memory range (exclusive). |
237 | * @type: Type of the memory range. |
238 | * |
239 | * This function is to find the memmap entey of a given memory range. |
240 | * The caller must hold map_entries_lock, and must not release the lock |
241 | * until the processing of the returned entry has completed. |
242 | * |
243 | * Return: Pointer to the entry to be found on success, or NULL on failure. |
244 | */ |
245 | static struct firmware_map_entry * __meminit |
246 | firmware_map_find_entry(u64 start, u64 end, const char *type) |
247 | { |
248 | return firmware_map_find_entry_in_list(start, end, type, list: &map_entries); |
249 | } |
250 | |
251 | /** |
252 | * firmware_map_find_entry_bootmem() - Search memmap entry in map_entries_bootmem. |
253 | * @start: Start of the memory range. |
254 | * @end: End of the memory range (exclusive). |
255 | * @type: Type of the memory range. |
256 | * |
257 | * This function is similar to firmware_map_find_entry except that it find the |
258 | * given entry in map_entries_bootmem. |
259 | * |
260 | * Return: Pointer to the entry to be found on success, or NULL on failure. |
261 | */ |
262 | static struct firmware_map_entry * __meminit |
263 | firmware_map_find_entry_bootmem(u64 start, u64 end, const char *type) |
264 | { |
265 | return firmware_map_find_entry_in_list(start, end, type, |
266 | list: &map_entries_bootmem); |
267 | } |
268 | |
269 | /** |
270 | * firmware_map_add_hotplug() - Adds a firmware mapping entry when we do |
271 | * memory hotplug. |
272 | * @start: Start of the memory range. |
273 | * @end: End of the memory range (exclusive) |
274 | * @type: Type of the memory range. |
275 | * |
276 | * Adds a firmware mapping entry. This function is for memory hotplug, it is |
277 | * similar to function firmware_map_add_early(). The only difference is that |
278 | * it will create the syfs entry dynamically. |
279 | * |
280 | * Return: 0 on success, or -ENOMEM if no memory could be allocated. |
281 | */ |
282 | int __meminit firmware_map_add_hotplug(u64 start, u64 end, const char *type) |
283 | { |
284 | struct firmware_map_entry *entry; |
285 | |
286 | entry = firmware_map_find_entry(start, end: end - 1, type); |
287 | if (entry) |
288 | return 0; |
289 | |
290 | entry = firmware_map_find_entry_bootmem(start, end: end - 1, type); |
291 | if (!entry) { |
292 | entry = kzalloc(size: sizeof(struct firmware_map_entry), GFP_ATOMIC); |
293 | if (!entry) |
294 | return -ENOMEM; |
295 | } else { |
296 | /* Reuse storage allocated by bootmem. */ |
297 | spin_lock(lock: &map_entries_bootmem_lock); |
298 | list_del(entry: &entry->list); |
299 | spin_unlock(lock: &map_entries_bootmem_lock); |
300 | |
301 | memset(entry, 0, sizeof(*entry)); |
302 | } |
303 | |
304 | firmware_map_add_entry(start, end, type, entry); |
305 | /* create the memmap entry */ |
306 | add_sysfs_fw_map_entry(entry); |
307 | |
308 | return 0; |
309 | } |
310 | |
311 | /** |
312 | * firmware_map_add_early() - Adds a firmware mapping entry. |
313 | * @start: Start of the memory range. |
314 | * @end: End of the memory range. |
315 | * @type: Type of the memory range. |
316 | * |
317 | * Adds a firmware mapping entry. This function uses the bootmem allocator |
318 | * for memory allocation. |
319 | * |
320 | * That function must be called before late_initcall. |
321 | * |
322 | * Return: 0 on success, or -ENOMEM if no memory could be allocated. |
323 | */ |
324 | int __init firmware_map_add_early(u64 start, u64 end, const char *type) |
325 | { |
326 | struct firmware_map_entry *entry; |
327 | |
328 | entry = memblock_alloc(size: sizeof(struct firmware_map_entry), |
329 | SMP_CACHE_BYTES); |
330 | if (WARN_ON(!entry)) |
331 | return -ENOMEM; |
332 | |
333 | return firmware_map_add_entry(start, end, type, entry); |
334 | } |
335 | |
336 | /** |
337 | * firmware_map_remove() - remove a firmware mapping entry |
338 | * @start: Start of the memory range. |
339 | * @end: End of the memory range. |
340 | * @type: Type of the memory range. |
341 | * |
342 | * removes a firmware mapping entry. |
343 | * |
344 | * Return: 0 on success, or -EINVAL if no entry. |
345 | */ |
346 | int __meminit firmware_map_remove(u64 start, u64 end, const char *type) |
347 | { |
348 | struct firmware_map_entry *entry; |
349 | |
350 | spin_lock(lock: &map_entries_lock); |
351 | entry = firmware_map_find_entry(start, end: end - 1, type); |
352 | if (!entry) { |
353 | spin_unlock(lock: &map_entries_lock); |
354 | return -EINVAL; |
355 | } |
356 | |
357 | firmware_map_remove_entry(entry); |
358 | spin_unlock(lock: &map_entries_lock); |
359 | |
360 | /* remove the memmap entry */ |
361 | remove_sysfs_fw_map_entry(entry); |
362 | |
363 | return 0; |
364 | } |
365 | |
366 | /* |
367 | * Sysfs functions ------------------------------------------------------------- |
368 | */ |
369 | |
370 | static ssize_t start_show(struct firmware_map_entry *entry, char *buf) |
371 | { |
372 | return snprintf(buf, PAGE_SIZE, fmt: "0x%llx\n" , |
373 | (unsigned long long)entry->start); |
374 | } |
375 | |
376 | static ssize_t end_show(struct firmware_map_entry *entry, char *buf) |
377 | { |
378 | return snprintf(buf, PAGE_SIZE, fmt: "0x%llx\n" , |
379 | (unsigned long long)entry->end); |
380 | } |
381 | |
382 | static ssize_t type_show(struct firmware_map_entry *entry, char *buf) |
383 | { |
384 | return snprintf(buf, PAGE_SIZE, fmt: "%s\n" , entry->type); |
385 | } |
386 | |
387 | static inline struct memmap_attribute *to_memmap_attr(struct attribute *attr) |
388 | { |
389 | return container_of(attr, struct memmap_attribute, attr); |
390 | } |
391 | |
392 | static ssize_t memmap_attr_show(struct kobject *kobj, |
393 | struct attribute *attr, char *buf) |
394 | { |
395 | struct firmware_map_entry *entry = to_memmap_entry(kobj); |
396 | struct memmap_attribute *memmap_attr = to_memmap_attr(attr); |
397 | |
398 | return memmap_attr->show(entry, buf); |
399 | } |
400 | |
401 | /* |
402 | * Initialises stuff and adds the entries in the map_entries list to |
403 | * sysfs. Important is that firmware_map_add() and firmware_map_add_early() |
404 | * must be called before late_initcall. That's just because that function |
405 | * is called as late_initcall() function, which means that if you call |
406 | * firmware_map_add() or firmware_map_add_early() afterwards, the entries |
407 | * are not added to sysfs. |
408 | */ |
409 | static int __init firmware_memmap_init(void) |
410 | { |
411 | struct firmware_map_entry *entry; |
412 | |
413 | list_for_each_entry(entry, &map_entries, list) |
414 | add_sysfs_fw_map_entry(entry); |
415 | |
416 | return 0; |
417 | } |
418 | late_initcall(firmware_memmap_init); |
419 | |
420 | |