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 */
26struct 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 */
41static ssize_t memmap_attr_show(struct kobject *kobj,
42 struct attribute *attr, char *buf);
43static ssize_t start_show(struct firmware_map_entry *entry, char *buf);
44static ssize_t end_show(struct firmware_map_entry *entry, char *buf);
45static ssize_t type_show(struct firmware_map_entry *entry, char *buf);
46
47static struct firmware_map_entry * __meminit
48firmware_map_find_entry(u64 start, u64 end, const char *type);
49
50/*
51 * Static data -----------------------------------------------------------------
52 */
53
54struct memmap_attribute {
55 struct attribute attr;
56 ssize_t (*show)(struct firmware_map_entry *entry, char *buf);
57};
58
59static struct memmap_attribute memmap_start_attr = __ATTR_RO(start);
60static struct memmap_attribute memmap_end_attr = __ATTR_RO(end);
61static struct memmap_attribute memmap_type_attr = __ATTR_RO(type);
62
63/*
64 * These are default attributes that are added for every memmap entry.
65 */
66static struct attribute *def_attrs[] = {
67 &memmap_start_attr.attr,
68 &memmap_end_attr.attr,
69 &memmap_type_attr.attr,
70 NULL
71};
72ATTRIBUTE_GROUPS(def);
73
74static const struct sysfs_ops memmap_attr_ops = {
75 .show = memmap_attr_show,
76};
77
78/* Firmware memory map entries. */
79static LIST_HEAD(map_entries);
80static 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 */
88static LIST_HEAD(map_entries_bootmem);
89static DEFINE_SPINLOCK(map_entries_bootmem_lock);
90
91
92static inline struct firmware_map_entry *
93to_memmap_entry(struct kobject *kobj)
94{
95 return container_of(kobj, struct firmware_map_entry, kobj);
96}
97
98static 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
119static const struct kobj_type 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 */
142static 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 */
168static 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 */
176static 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 */
200static 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 */
218static struct firmware_map_entry * __meminit
219firmware_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 */
245static struct firmware_map_entry * __meminit
246firmware_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 */
262static struct firmware_map_entry * __meminit
263firmware_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 */
282int __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(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(s: entry, c: 0, n: 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 */
324int __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 */
346int __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
370static 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
376static 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
382static 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
387static inline struct memmap_attribute *to_memmap_attr(struct attribute *attr)
388{
389 return container_of(attr, struct memmap_attribute, attr);
390}
391
392static 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 */
409static 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}
418late_initcall(firmware_memmap_init);
419
420