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92281dee
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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 */
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13#include <linux/radix-tree.h>
14#include <linux/memremap.h>
7d3dcf26 15#include <linux/device.h>
92281dee 16#include <linux/types.h>
34c0fd54 17#include <linux/pfn_t.h>
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18#include <linux/io.h>
19#include <linux/mm.h>
41e94a85 20#include <linux/memory_hotplug.h>
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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
182475b7
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30static void *try_ram_remap(resource_size_t offset, size_t size)
31{
32 struct page *page = pfn_to_page(offset >> PAGE_SHIFT);
33
34 /* In the simple case just return the existing linear address */
35 if (!PageHighMem(page))
36 return __va(offset);
37 return NULL; /* fallback to ioremap_cache */
38}
39
92281dee
DW
40/**
41 * memremap() - remap an iomem_resource as cacheable memory
42 * @offset: iomem resource start address
43 * @size: size of remap
44 * @flags: either MEMREMAP_WB or MEMREMAP_WT
45 *
46 * memremap() is "ioremap" for cases where it is known that the resource
47 * being mapped does not have i/o side effects and the __iomem
48 * annotation is not applicable.
49 *
50 * MEMREMAP_WB - matches the default mapping for "System RAM" on
51 * the architecture. This is usually a read-allocate write-back cache.
52 * Morever, if MEMREMAP_WB is specified and the requested remap region is RAM
53 * memremap() will bypass establishing a new mapping and instead return
54 * a pointer into the direct map.
55 *
56 * MEMREMAP_WT - establish a mapping whereby writes either bypass the
57 * cache or are written through to memory and never exist in a
58 * cache-dirty state with respect to program visibility. Attempts to
59 * map "System RAM" with this mapping type will fail.
60 */
61void *memremap(resource_size_t offset, size_t size, unsigned long flags)
62{
63 int is_ram = region_intersects(offset, size, "System RAM");
64 void *addr = NULL;
65
66 if (is_ram == REGION_MIXED) {
67 WARN_ONCE(1, "memremap attempted on mixed range %pa size: %#lx\n",
68 &offset, (unsigned long) size);
69 return NULL;
70 }
71
72 /* Try all mapping types requested until one returns non-NULL */
73 if (flags & MEMREMAP_WB) {
74 flags &= ~MEMREMAP_WB;
75 /*
76 * MEMREMAP_WB is special in that it can be satisifed
77 * from the direct map. Some archs depend on the
78 * capability of memremap() to autodetect cases where
79 * the requested range is potentially in "System RAM"
80 */
81 if (is_ram == REGION_INTERSECTS)
182475b7
DW
82 addr = try_ram_remap(offset, size);
83 if (!addr)
92281dee
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84 addr = ioremap_cache(offset, size);
85 }
86
87 /*
88 * If we don't have a mapping yet and more request flags are
89 * pending then we will be attempting to establish a new virtual
90 * address mapping. Enforce that this mapping is not aliasing
91 * "System RAM"
92 */
93 if (!addr && is_ram == REGION_INTERSECTS && flags) {
94 WARN_ONCE(1, "memremap attempted on ram %pa size: %#lx\n",
95 &offset, (unsigned long) size);
96 return NULL;
97 }
98
99 if (!addr && (flags & MEMREMAP_WT)) {
100 flags &= ~MEMREMAP_WT;
101 addr = ioremap_wt(offset, size);
102 }
103
104 return addr;
105}
106EXPORT_SYMBOL(memremap);
107
108void memunmap(void *addr)
109{
110 if (is_vmalloc_addr(addr))
111 iounmap((void __iomem *) addr);
112}
113EXPORT_SYMBOL(memunmap);
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114
115static void devm_memremap_release(struct device *dev, void *res)
116{
9273a8bb 117 memunmap(*(void **)res);
7d3dcf26
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118}
119
120static int devm_memremap_match(struct device *dev, void *res, void *match_data)
121{
122 return *(void **)res == match_data;
123}
124
125void *devm_memremap(struct device *dev, resource_size_t offset,
126 size_t size, unsigned long flags)
127{
128 void **ptr, *addr;
129
538ea4aa
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130 ptr = devres_alloc_node(devm_memremap_release, sizeof(*ptr), GFP_KERNEL,
131 dev_to_node(dev));
7d3dcf26 132 if (!ptr)
b36f4761 133 return ERR_PTR(-ENOMEM);
7d3dcf26
CH
134
135 addr = memremap(offset, size, flags);
136 if (addr) {
137 *ptr = addr;
138 devres_add(dev, ptr);
93f834df 139 } else {
7d3dcf26 140 devres_free(ptr);
93f834df
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141 return ERR_PTR(-ENXIO);
142 }
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143
144 return addr;
145}
146EXPORT_SYMBOL(devm_memremap);
147
148void devm_memunmap(struct device *dev, void *addr)
149{
d741314f
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150 WARN_ON(devres_release(dev, devm_memremap_release,
151 devm_memremap_match, addr));
7d3dcf26
CH
152}
153EXPORT_SYMBOL(devm_memunmap);
41e94a85 154
db78c222 155pfn_t phys_to_pfn_t(phys_addr_t addr, u64 flags)
34c0fd54
DW
156{
157 return __pfn_to_pfn_t(addr >> PAGE_SHIFT, flags);
158}
159EXPORT_SYMBOL(phys_to_pfn_t);
160
41e94a85 161#ifdef CONFIG_ZONE_DEVICE
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162static DEFINE_MUTEX(pgmap_lock);
163static RADIX_TREE(pgmap_radix, GFP_KERNEL);
164#define SECTION_MASK ~((1UL << PA_SECTION_SHIFT) - 1)
165#define SECTION_SIZE (1UL << PA_SECTION_SHIFT)
166
41e94a85
CH
167struct page_map {
168 struct resource res;
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169 struct percpu_ref *ref;
170 struct dev_pagemap pgmap;
4b94ffdc 171 struct vmem_altmap altmap;
41e94a85
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172};
173
3565fce3
DW
174void get_zone_device_page(struct page *page)
175{
176 percpu_ref_get(page->pgmap->ref);
177}
178EXPORT_SYMBOL(get_zone_device_page);
179
180void put_zone_device_page(struct page *page)
181{
182 put_dev_pagemap(page->pgmap);
183}
184EXPORT_SYMBOL(put_zone_device_page);
185
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186static void pgmap_radix_release(struct resource *res)
187{
eb7d78c9
DW
188 resource_size_t key, align_start, align_size, align_end;
189
190 align_start = res->start & ~(SECTION_SIZE - 1);
191 align_size = ALIGN(resource_size(res), SECTION_SIZE);
192 align_end = align_start + align_size - 1;
9476df7d
DW
193
194 mutex_lock(&pgmap_lock);
195 for (key = res->start; key <= res->end; key += SECTION_SIZE)
196 radix_tree_delete(&pgmap_radix, key >> PA_SECTION_SHIFT);
197 mutex_unlock(&pgmap_lock);
198}
199
5c2c2587
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200static unsigned long pfn_first(struct page_map *page_map)
201{
202 struct dev_pagemap *pgmap = &page_map->pgmap;
203 const struct resource *res = &page_map->res;
204 struct vmem_altmap *altmap = pgmap->altmap;
205 unsigned long pfn;
206
207 pfn = res->start >> PAGE_SHIFT;
208 if (altmap)
209 pfn += vmem_altmap_offset(altmap);
210 return pfn;
211}
212
213static unsigned long pfn_end(struct page_map *page_map)
214{
215 const struct resource *res = &page_map->res;
216
217 return (res->start + resource_size(res)) >> PAGE_SHIFT;
218}
219
220#define for_each_device_pfn(pfn, map) \
221 for (pfn = pfn_first(map); pfn < pfn_end(map); pfn++)
222
9476df7d 223static void devm_memremap_pages_release(struct device *dev, void *data)
41e94a85 224{
9476df7d
DW
225 struct page_map *page_map = data;
226 struct resource *res = &page_map->res;
227 resource_size_t align_start, align_size;
4b94ffdc 228 struct dev_pagemap *pgmap = &page_map->pgmap;
9476df7d 229
5c2c2587
DW
230 if (percpu_ref_tryget_live(pgmap->ref)) {
231 dev_WARN(dev, "%s: page mapping is still live!\n", __func__);
232 percpu_ref_put(pgmap->ref);
233 }
234
41e94a85 235 /* pages are dead and unused, undo the arch mapping */
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236 align_start = res->start & ~(SECTION_SIZE - 1);
237 align_size = ALIGN(resource_size(res), SECTION_SIZE);
238 arch_remove_memory(align_start, align_size);
eb7d78c9 239 pgmap_radix_release(res);
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240 dev_WARN_ONCE(dev, pgmap->altmap && pgmap->altmap->alloc,
241 "%s: failed to free all reserved pages\n", __func__);
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242}
243
244/* assumes rcu_read_lock() held at entry */
245struct dev_pagemap *find_dev_pagemap(resource_size_t phys)
246{
247 struct page_map *page_map;
248
249 WARN_ON_ONCE(!rcu_read_lock_held());
250
251 page_map = radix_tree_lookup(&pgmap_radix, phys >> PA_SECTION_SHIFT);
252 return page_map ? &page_map->pgmap : NULL;
41e94a85
CH
253}
254
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255/**
256 * devm_memremap_pages - remap and provide memmap backing for the given resource
257 * @dev: hosting device for @res
258 * @res: "host memory" address range
5c2c2587 259 * @ref: a live per-cpu reference count
4b94ffdc
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260 * @altmap: optional descriptor for allocating the memmap from @res
261 *
5c2c2587
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262 * Notes:
263 * 1/ @ref must be 'live' on entry and 'dead' before devm_memunmap_pages() time
264 * (or devm release event).
265 *
266 * 2/ @res is expected to be a host memory range that could feasibly be
267 * treated as a "System RAM" range, i.e. not a device mmio range, but
268 * this is not enforced.
4b94ffdc
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269 */
270void *devm_memremap_pages(struct device *dev, struct resource *res,
5c2c2587 271 struct percpu_ref *ref, struct vmem_altmap *altmap)
41e94a85
CH
272{
273 int is_ram = region_intersects(res->start, resource_size(res),
274 "System RAM");
eb7d78c9 275 resource_size_t key, align_start, align_size, align_end;
4b94ffdc 276 struct dev_pagemap *pgmap;
41e94a85 277 struct page_map *page_map;
5c2c2587 278 unsigned long pfn;
41e94a85
CH
279 int error, nid;
280
281 if (is_ram == REGION_MIXED) {
282 WARN_ONCE(1, "%s attempted on mixed region %pr\n",
283 __func__, res);
284 return ERR_PTR(-ENXIO);
285 }
286
287 if (is_ram == REGION_INTERSECTS)
288 return __va(res->start);
289
4b94ffdc
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290 if (altmap && !IS_ENABLED(CONFIG_SPARSEMEM_VMEMMAP)) {
291 dev_err(dev, "%s: altmap requires CONFIG_SPARSEMEM_VMEMMAP=y\n",
292 __func__);
293 return ERR_PTR(-ENXIO);
294 }
295
5c2c2587
DW
296 if (!ref)
297 return ERR_PTR(-EINVAL);
298
538ea4aa
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299 page_map = devres_alloc_node(devm_memremap_pages_release,
300 sizeof(*page_map), GFP_KERNEL, dev_to_node(dev));
41e94a85
CH
301 if (!page_map)
302 return ERR_PTR(-ENOMEM);
4b94ffdc 303 pgmap = &page_map->pgmap;
41e94a85
CH
304
305 memcpy(&page_map->res, res, sizeof(*res));
306
4b94ffdc
DW
307 pgmap->dev = dev;
308 if (altmap) {
309 memcpy(&page_map->altmap, altmap, sizeof(*altmap));
310 pgmap->altmap = &page_map->altmap;
311 }
5c2c2587 312 pgmap->ref = ref;
4b94ffdc
DW
313 pgmap->res = &page_map->res;
314
9476df7d
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315 mutex_lock(&pgmap_lock);
316 error = 0;
eb7d78c9
DW
317 align_start = res->start & ~(SECTION_SIZE - 1);
318 align_size = ALIGN(resource_size(res), SECTION_SIZE);
319 align_end = align_start + align_size - 1;
320 for (key = align_start; key <= align_end; key += SECTION_SIZE) {
9476df7d
DW
321 struct dev_pagemap *dup;
322
323 rcu_read_lock();
324 dup = find_dev_pagemap(key);
325 rcu_read_unlock();
326 if (dup) {
327 dev_err(dev, "%s: %pr collides with mapping for %s\n",
328 __func__, res, dev_name(dup->dev));
329 error = -EBUSY;
330 break;
331 }
332 error = radix_tree_insert(&pgmap_radix, key >> PA_SECTION_SHIFT,
333 page_map);
334 if (error) {
335 dev_err(dev, "%s: failed: %d\n", __func__, error);
336 break;
337 }
338 }
339 mutex_unlock(&pgmap_lock);
340 if (error)
341 goto err_radix;
342
41e94a85
CH
343 nid = dev_to_node(dev);
344 if (nid < 0)
7eff93b7 345 nid = numa_mem_id();
41e94a85 346
9476df7d
DW
347 error = arch_add_memory(nid, align_start, align_size, true);
348 if (error)
349 goto err_add_memory;
41e94a85 350
5c2c2587
DW
351 for_each_device_pfn(pfn, page_map) {
352 struct page *page = pfn_to_page(pfn);
353
354 /* ZONE_DEVICE pages must never appear on a slab lru */
355 list_force_poison(&page->lru);
356 page->pgmap = pgmap;
357 }
41e94a85
CH
358 devres_add(dev, page_map);
359 return __va(res->start);
9476df7d
DW
360
361 err_add_memory:
362 err_radix:
363 pgmap_radix_release(res);
364 devres_free(page_map);
365 return ERR_PTR(error);
41e94a85
CH
366}
367EXPORT_SYMBOL(devm_memremap_pages);
4b94ffdc
DW
368
369unsigned long vmem_altmap_offset(struct vmem_altmap *altmap)
370{
371 /* number of pfns from base where pfn_to_page() is valid */
372 return altmap->reserve + altmap->free;
373}
374
375void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns)
376{
377 altmap->alloc -= nr_pfns;
378}
379
380#ifdef CONFIG_SPARSEMEM_VMEMMAP
381struct vmem_altmap *to_vmem_altmap(unsigned long memmap_start)
382{
383 /*
384 * 'memmap_start' is the virtual address for the first "struct
385 * page" in this range of the vmemmap array. In the case of
386 * CONFIG_SPARSE_VMEMMAP a page_to_pfn conversion is simple
387 * pointer arithmetic, so we can perform this to_vmem_altmap()
388 * conversion without concern for the initialization state of
389 * the struct page fields.
390 */
391 struct page *page = (struct page *) memmap_start;
392 struct dev_pagemap *pgmap;
393
394 /*
395 * Uncoditionally retrieve a dev_pagemap associated with the
396 * given physical address, this is only for use in the
397 * arch_{add|remove}_memory() for setting up and tearing down
398 * the memmap.
399 */
400 rcu_read_lock();
401 pgmap = find_dev_pagemap(__pfn_to_phys(page_to_pfn(page)));
402 rcu_read_unlock();
403
404 return pgmap ? pgmap->altmap : NULL;
405}
406#endif /* CONFIG_SPARSEMEM_VMEMMAP */
41e94a85 407#endif /* CONFIG_ZONE_DEVICE */