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path: root/kernel/memremap.c (plain)
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1/*
2 * Copyright(c) 2015 Intel Corporation. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of version 2 of the GNU General Public License as
6 * published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful, but
9 * WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 */
13#include <linux/radix-tree.h>
14#include <linux/memremap.h>
15#include <linux/device.h>
16#include <linux/types.h>
17#include <linux/pfn_t.h>
18#include <linux/io.h>
19#include <linux/mm.h>
20#include <linux/memory_hotplug.h>
21
22#ifndef ioremap_cache
23/* temporary while we convert existing ioremap_cache users to memremap */
24__weak void __iomem *ioremap_cache(resource_size_t offset, unsigned long size)
25{
26 return ioremap(offset, size);
27}
28#endif
29
30#ifndef arch_memremap_wb
31static void *arch_memremap_wb(resource_size_t offset, unsigned long size)
32{
33 return (__force void *)ioremap_cache(offset, size);
34}
35#endif
36
37static void *try_ram_remap(resource_size_t offset, size_t size)
38{
39 unsigned long pfn = PHYS_PFN(offset);
40
41 /* In the simple case just return the existing linear address */
42 if (pfn_valid(pfn) && !PageHighMem(pfn_to_page(pfn)))
43 return __va(offset);
44 return NULL; /* fallback to arch_memremap_wb */
45}
46
47/**
48 * memremap() - remap an iomem_resource as cacheable memory
49 * @offset: iomem resource start address
50 * @size: size of remap
51 * @flags: any of MEMREMAP_WB, MEMREMAP_WT and MEMREMAP_WC
52 *
53 * memremap() is "ioremap" for cases where it is known that the resource
54 * being mapped does not have i/o side effects and the __iomem
55 * annotation is not applicable. In the case of multiple flags, the different
56 * mapping types will be attempted in the order listed below until one of
57 * them succeeds.
58 *
59 * MEMREMAP_WB - matches the default mapping for System RAM on
60 * the architecture. This is usually a read-allocate write-back cache.
61 * Morever, if MEMREMAP_WB is specified and the requested remap region is RAM
62 * memremap() will bypass establishing a new mapping and instead return
63 * a pointer into the direct map.
64 *
65 * MEMREMAP_WT - establish a mapping whereby writes either bypass the
66 * cache or are written through to memory and never exist in a
67 * cache-dirty state with respect to program visibility. Attempts to
68 * map System RAM with this mapping type will fail.
69 *
70 * MEMREMAP_WC - establish a writecombine mapping, whereby writes may
71 * be coalesced together (e.g. in the CPU's write buffers), but is otherwise
72 * uncached. Attempts to map System RAM with this mapping type will fail.
73 */
74void *memremap(resource_size_t offset, size_t size, unsigned long flags)
75{
76 int is_ram = region_intersects(offset, size,
77 IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE);
78 void *addr = NULL;
79
80 if (!flags)
81 return NULL;
82
83 if (is_ram == REGION_MIXED) {
84 WARN_ONCE(1, "memremap attempted on mixed range %pa size: %#lx\n",
85 &offset, (unsigned long) size);
86 return NULL;
87 }
88
89 /* Try all mapping types requested until one returns non-NULL */
90 if (flags & MEMREMAP_WB) {
91 /*
92 * MEMREMAP_WB is special in that it can be satisifed
93 * from the direct map. Some archs depend on the
94 * capability of memremap() to autodetect cases where
95 * the requested range is potentially in System RAM.
96 */
97 if (is_ram == REGION_INTERSECTS)
98 addr = try_ram_remap(offset, size);
99 if (!addr)
100 addr = arch_memremap_wb(offset, size);
101 }
102
103 /*
104 * If we don't have a mapping yet and other request flags are
105 * present then we will be attempting to establish a new virtual
106 * address mapping. Enforce that this mapping is not aliasing
107 * System RAM.
108 */
109 if (!addr && is_ram == REGION_INTERSECTS && flags != MEMREMAP_WB) {
110 WARN_ONCE(1, "memremap attempted on ram %pa size: %#lx\n",
111 &offset, (unsigned long) size);
112 return NULL;
113 }
114
115 if (!addr && (flags & MEMREMAP_WT))
116 addr = ioremap_wt(offset, size);
117
118 if (!addr && (flags & MEMREMAP_WC))
119 addr = ioremap_wc(offset, size);
120
121 return addr;
122}
123EXPORT_SYMBOL(memremap);
124
125void memunmap(void *addr)
126{
127 if (is_vmalloc_addr(addr))
128 iounmap((void __iomem *) addr);
129}
130EXPORT_SYMBOL(memunmap);
131
132static void devm_memremap_release(struct device *dev, void *res)
133{
134 memunmap(*(void **)res);
135}
136
137static int devm_memremap_match(struct device *dev, void *res, void *match_data)
138{
139 return *(void **)res == match_data;
140}
141
142void *devm_memremap(struct device *dev, resource_size_t offset,
143 size_t size, unsigned long flags)
144{
145 void **ptr, *addr;
146
147 ptr = devres_alloc_node(devm_memremap_release, sizeof(*ptr), GFP_KERNEL,
148 dev_to_node(dev));
149 if (!ptr)
150 return ERR_PTR(-ENOMEM);
151
152 addr = memremap(offset, size, flags);
153 if (addr) {
154 *ptr = addr;
155 devres_add(dev, ptr);
156 } else {
157 devres_free(ptr);
158 return ERR_PTR(-ENXIO);
159 }
160
161 return addr;
162}
163EXPORT_SYMBOL(devm_memremap);
164
165void devm_memunmap(struct device *dev, void *addr)
166{
167 WARN_ON(devres_release(dev, devm_memremap_release,
168 devm_memremap_match, addr));
169}
170EXPORT_SYMBOL(devm_memunmap);
171
172#ifdef CONFIG_ZONE_DEVICE
173static DEFINE_MUTEX(pgmap_lock);
174static RADIX_TREE(pgmap_radix, GFP_KERNEL);
175#define SECTION_MASK ~((1UL << PA_SECTION_SHIFT) - 1)
176#define SECTION_SIZE (1UL << PA_SECTION_SHIFT)
177
178struct page_map {
179 struct resource res;
180 struct percpu_ref *ref;
181 struct dev_pagemap pgmap;
182 struct vmem_altmap altmap;
183};
184
185void get_zone_device_page(struct page *page)
186{
187 percpu_ref_get(page->pgmap->ref);
188}
189EXPORT_SYMBOL(get_zone_device_page);
190
191void put_zone_device_page(struct page *page)
192{
193 put_dev_pagemap(page->pgmap);
194}
195EXPORT_SYMBOL(put_zone_device_page);
196
197static void pgmap_radix_release(struct resource *res, resource_size_t end_key)
198{
199 resource_size_t key, align_start, align_size, align_end;
200
201 align_start = res->start & ~(SECTION_SIZE - 1);
202 align_size = ALIGN(resource_size(res), SECTION_SIZE);
203 align_end = align_start + align_size - 1;
204
205 mutex_lock(&pgmap_lock);
206 for (key = res->start; key <= res->end; key += SECTION_SIZE) {
207 if (key >= end_key)
208 break;
209 radix_tree_delete(&pgmap_radix, key >> PA_SECTION_SHIFT);
210 }
211 mutex_unlock(&pgmap_lock);
212}
213
214static unsigned long pfn_first(struct page_map *page_map)
215{
216 struct dev_pagemap *pgmap = &page_map->pgmap;
217 const struct resource *res = &page_map->res;
218 struct vmem_altmap *altmap = pgmap->altmap;
219 unsigned long pfn;
220
221 pfn = res->start >> PAGE_SHIFT;
222 if (altmap)
223 pfn += vmem_altmap_offset(altmap);
224 return pfn;
225}
226
227static unsigned long pfn_end(struct page_map *page_map)
228{
229 const struct resource *res = &page_map->res;
230
231 return (res->start + resource_size(res)) >> PAGE_SHIFT;
232}
233
234#define for_each_device_pfn(pfn, map) \
235 for (pfn = pfn_first(map); pfn < pfn_end(map); pfn++)
236
237static void devm_memremap_pages_release(struct device *dev, void *data)
238{
239 struct page_map *page_map = data;
240 struct resource *res = &page_map->res;
241 resource_size_t align_start, align_size;
242 struct dev_pagemap *pgmap = &page_map->pgmap;
243
244 if (percpu_ref_tryget_live(pgmap->ref)) {
245 dev_WARN(dev, "%s: page mapping is still live!\n", __func__);
246 percpu_ref_put(pgmap->ref);
247 }
248
249 /* pages are dead and unused, undo the arch mapping */
250 align_start = res->start & ~(SECTION_SIZE - 1);
251 align_size = ALIGN(res->start + resource_size(res), SECTION_SIZE)
252 - align_start;
253
254 lock_device_hotplug();
255 mem_hotplug_begin();
256 arch_remove_memory(align_start, align_size);
257 mem_hotplug_done();
258 unlock_device_hotplug();
259
260 untrack_pfn(NULL, PHYS_PFN(align_start), align_size);
261 pgmap_radix_release(res, -1);
262 dev_WARN_ONCE(dev, pgmap->altmap && pgmap->altmap->alloc,
263 "%s: failed to free all reserved pages\n", __func__);
264}
265
266/* assumes rcu_read_lock() held at entry */
267struct dev_pagemap *find_dev_pagemap(resource_size_t phys)
268{
269 struct page_map *page_map;
270
271 WARN_ON_ONCE(!rcu_read_lock_held());
272
273 page_map = radix_tree_lookup(&pgmap_radix, phys >> PA_SECTION_SHIFT);
274 return page_map ? &page_map->pgmap : NULL;
275}
276
277/**
278 * devm_memremap_pages - remap and provide memmap backing for the given resource
279 * @dev: hosting device for @res
280 * @res: "host memory" address range
281 * @ref: a live per-cpu reference count
282 * @altmap: optional descriptor for allocating the memmap from @res
283 *
284 * Notes:
285 * 1/ @ref must be 'live' on entry and 'dead' before devm_memunmap_pages() time
286 * (or devm release event).
287 *
288 * 2/ @res is expected to be a host memory range that could feasibly be
289 * treated as a "System RAM" range, i.e. not a device mmio range, but
290 * this is not enforced.
291 */
292void *devm_memremap_pages(struct device *dev, struct resource *res,
293 struct percpu_ref *ref, struct vmem_altmap *altmap)
294{
295 resource_size_t key = 0, align_start, align_size, align_end;
296 pgprot_t pgprot = PAGE_KERNEL;
297 struct dev_pagemap *pgmap;
298 struct page_map *page_map;
299 int error, nid, is_ram;
300 unsigned long pfn;
301
302 align_start = res->start & ~(SECTION_SIZE - 1);
303 align_size = ALIGN(res->start + resource_size(res), SECTION_SIZE)
304 - align_start;
305 is_ram = region_intersects(align_start, align_size,
306 IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE);
307
308 if (is_ram != REGION_DISJOINT) {
309 WARN_ONCE(1, "%s attempted on %s region %pr\n", __func__,
310 is_ram == REGION_MIXED ? "mixed" : "ram", res);
311 return ERR_PTR(-ENXIO);
312 }
313
314 if (!ref)
315 return ERR_PTR(-EINVAL);
316
317 page_map = devres_alloc_node(devm_memremap_pages_release,
318 sizeof(*page_map), GFP_KERNEL, dev_to_node(dev));
319 if (!page_map)
320 return ERR_PTR(-ENOMEM);
321 pgmap = &page_map->pgmap;
322
323 memcpy(&page_map->res, res, sizeof(*res));
324
325 pgmap->dev = dev;
326 if (altmap) {
327 memcpy(&page_map->altmap, altmap, sizeof(*altmap));
328 pgmap->altmap = &page_map->altmap;
329 }
330 pgmap->ref = ref;
331 pgmap->res = &page_map->res;
332
333 mutex_lock(&pgmap_lock);
334 error = 0;
335 align_end = align_start + align_size - 1;
336 for (key = align_start; key <= align_end; key += SECTION_SIZE) {
337 struct dev_pagemap *dup;
338
339 rcu_read_lock();
340 dup = find_dev_pagemap(key);
341 rcu_read_unlock();
342 if (dup) {
343 dev_err(dev, "%s: %pr collides with mapping for %s\n",
344 __func__, res, dev_name(dup->dev));
345 error = -EBUSY;
346 break;
347 }
348 error = radix_tree_insert(&pgmap_radix, key >> PA_SECTION_SHIFT,
349 page_map);
350 if (error) {
351 dev_err(dev, "%s: failed: %d\n", __func__, error);
352 break;
353 }
354 }
355 mutex_unlock(&pgmap_lock);
356 if (error)
357 goto err_radix;
358
359 nid = dev_to_node(dev);
360 if (nid < 0)
361 nid = numa_mem_id();
362
363 error = track_pfn_remap(NULL, &pgprot, PHYS_PFN(align_start), 0,
364 align_size);
365 if (error)
366 goto err_pfn_remap;
367
368 lock_device_hotplug();
369 mem_hotplug_begin();
370 error = arch_add_memory(nid, align_start, align_size, true);
371 mem_hotplug_done();
372 unlock_device_hotplug();
373 if (error)
374 goto err_add_memory;
375
376 for_each_device_pfn(pfn, page_map) {
377 struct page *page = pfn_to_page(pfn);
378
379 /*
380 * ZONE_DEVICE pages union ->lru with a ->pgmap back
381 * pointer. It is a bug if a ZONE_DEVICE page is ever
382 * freed or placed on a driver-private list. Seed the
383 * storage with LIST_POISON* values.
384 */
385 list_del(&page->lru);
386 page->pgmap = pgmap;
387 }
388 devres_add(dev, page_map);
389 return __va(res->start);
390
391 err_add_memory:
392 untrack_pfn(NULL, PHYS_PFN(align_start), align_size);
393 err_pfn_remap:
394 err_radix:
395 pgmap_radix_release(res, key);
396 devres_free(page_map);
397 return ERR_PTR(error);
398}
399EXPORT_SYMBOL_GPL(devm_memremap_pages);
400
401unsigned long vmem_altmap_offset(struct vmem_altmap *altmap)
402{
403 /* number of pfns from base where pfn_to_page() is valid */
404 return altmap->reserve + altmap->free;
405}
406
407void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns)
408{
409 altmap->alloc -= nr_pfns;
410}
411
412struct vmem_altmap *to_vmem_altmap(unsigned long memmap_start)
413{
414 /*
415 * 'memmap_start' is the virtual address for the first "struct
416 * page" in this range of the vmemmap array. In the case of
417 * CONFIG_SPARSEMEM_VMEMMAP a page_to_pfn conversion is simple
418 * pointer arithmetic, so we can perform this to_vmem_altmap()
419 * conversion without concern for the initialization state of
420 * the struct page fields.
421 */
422 struct page *page = (struct page *) memmap_start;
423 struct dev_pagemap *pgmap;
424
425 /*
426 * Unconditionally retrieve a dev_pagemap associated with the
427 * given physical address, this is only for use in the
428 * arch_{add|remove}_memory() for setting up and tearing down
429 * the memmap.
430 */
431 rcu_read_lock();
432 pgmap = find_dev_pagemap(__pfn_to_phys(page_to_pfn(page)));
433 rcu_read_unlock();
434
435 return pgmap ? pgmap->altmap : NULL;
436}
437#endif /* CONFIG_ZONE_DEVICE */
438
generated by cgit at 2024-05-18 14:50:57 (GMT)