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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
c269cba3
AB
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
182475b7
DW
37static void *try_ram_remap(resource_size_t offset, size_t size)
38{
ac343e88 39 unsigned long pfn = PHYS_PFN(offset);
182475b7
DW
40
41 /* In the simple case just return the existing linear address */
ac343e88 42 if (pfn_valid(pfn) && !PageHighMem(pfn_to_page(pfn)))
182475b7 43 return __va(offset);
c269cba3 44 return NULL; /* fallback to arch_memremap_wb */
182475b7
DW
45}
46
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47/**
48 * memremap() - remap an iomem_resource as cacheable memory
49 * @offset: iomem resource start address
50 * @size: size of remap
c907e0eb 51 * @flags: any of MEMREMAP_WB, MEMREMAP_WT and MEMREMAP_WC
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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
c907e0eb
BS
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.
92281dee 58 *
1c29f25b 59 * MEMREMAP_WB - matches the default mapping for System RAM on
92281dee
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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
1c29f25b 68 * map System RAM with this mapping type will fail.
c907e0eb
BS
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.
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73 */
74void *memremap(resource_size_t offset, size_t size, unsigned long flags)
75{
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76 int is_ram = region_intersects(offset, size,
77 IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE);
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78 void *addr = NULL;
79
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80 if (!flags)
81 return NULL;
82
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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) {
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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
1c29f25b 95 * the requested range is potentially in System RAM.
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96 */
97 if (is_ram == REGION_INTERSECTS)
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98 addr = try_ram_remap(offset, size);
99 if (!addr)
c269cba3 100 addr = arch_memremap_wb(offset, size);
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101 }
102
103 /*
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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
92281dee 106 * address mapping. Enforce that this mapping is not aliasing
1c29f25b 107 * System RAM.
92281dee 108 */
cf61e2a1 109 if (!addr && is_ram == REGION_INTERSECTS && flags != MEMREMAP_WB) {
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110 WARN_ONCE(1, "memremap attempted on ram %pa size: %#lx\n",
111 &offset, (unsigned long) size);
112 return NULL;
113 }
114
cf61e2a1 115 if (!addr && (flags & MEMREMAP_WT))
92281dee 116 addr = ioremap_wt(offset, size);
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BS
117
118 if (!addr && (flags & MEMREMAP_WC))
119 addr = ioremap_wc(offset, size);
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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);
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CH
131
132static void devm_memremap_release(struct device *dev, void *res)
133{
9273a8bb 134 memunmap(*(void **)res);
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CH
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
538ea4aa
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147 ptr = devres_alloc_node(devm_memremap_release, sizeof(*ptr), GFP_KERNEL,
148 dev_to_node(dev));
7d3dcf26 149 if (!ptr)
b36f4761 150 return ERR_PTR(-ENOMEM);
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CH
151
152 addr = memremap(offset, size, flags);
153 if (addr) {
154 *ptr = addr;
155 devres_add(dev, ptr);
93f834df 156 } else {
7d3dcf26 157 devres_free(ptr);
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TK
158 return ERR_PTR(-ENXIO);
159 }
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CH
160
161 return addr;
162}
163EXPORT_SYMBOL(devm_memremap);
164
165void devm_memunmap(struct device *dev, void *addr)
166{
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167 WARN_ON(devres_release(dev, devm_memremap_release,
168 devm_memremap_match, addr));
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CH
169}
170EXPORT_SYMBOL(devm_memunmap);
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171
172#ifdef CONFIG_ZONE_DEVICE
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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
41e94a85
CH
178struct page_map {
179 struct resource res;
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DW
180 struct percpu_ref *ref;
181 struct dev_pagemap pgmap;
4b94ffdc 182 struct vmem_altmap altmap;
41e94a85
CH
183};
184
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185static void pgmap_radix_release(struct resource *res)
186{
eb7d78c9
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187 resource_size_t key, align_start, align_size, align_end;
188
189 align_start = res->start & ~(SECTION_SIZE - 1);
190 align_size = ALIGN(resource_size(res), SECTION_SIZE);
191 align_end = align_start + align_size - 1;
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DW
192
193 mutex_lock(&pgmap_lock);
194 for (key = res->start; key <= res->end; key += SECTION_SIZE)
195 radix_tree_delete(&pgmap_radix, key >> PA_SECTION_SHIFT);
196 mutex_unlock(&pgmap_lock);
197}
198
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199static unsigned long pfn_first(struct page_map *page_map)
200{
201 struct dev_pagemap *pgmap = &page_map->pgmap;
202 const struct resource *res = &page_map->res;
203 struct vmem_altmap *altmap = pgmap->altmap;
204 unsigned long pfn;
205
206 pfn = res->start >> PAGE_SHIFT;
207 if (altmap)
208 pfn += vmem_altmap_offset(altmap);
209 return pfn;
210}
211
212static unsigned long pfn_end(struct page_map *page_map)
213{
214 const struct resource *res = &page_map->res;
215
216 return (res->start + resource_size(res)) >> PAGE_SHIFT;
217}
218
219#define for_each_device_pfn(pfn, map) \
220 for (pfn = pfn_first(map); pfn < pfn_end(map); pfn++)
221
9476df7d 222static void devm_memremap_pages_release(struct device *dev, void *data)
41e94a85 223{
9476df7d
DW
224 struct page_map *page_map = data;
225 struct resource *res = &page_map->res;
226 resource_size_t align_start, align_size;
4b94ffdc 227 struct dev_pagemap *pgmap = &page_map->pgmap;
71389703
DW
228 unsigned long pfn;
229
230 for_each_device_pfn(pfn, page_map)
231 put_page(pfn_to_page(pfn));
9476df7d 232
5c2c2587
DW
233 if (percpu_ref_tryget_live(pgmap->ref)) {
234 dev_WARN(dev, "%s: page mapping is still live!\n", __func__);
235 percpu_ref_put(pgmap->ref);
236 }
237
41e94a85 238 /* pages are dead and unused, undo the arch mapping */
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DW
239 align_start = res->start & ~(SECTION_SIZE - 1);
240 align_size = ALIGN(resource_size(res), SECTION_SIZE);
b5d24fda 241
f931ab47 242 mem_hotplug_begin();
9476df7d 243 arch_remove_memory(align_start, align_size);
f931ab47 244 mem_hotplug_done();
b5d24fda 245
9049771f 246 untrack_pfn(NULL, PHYS_PFN(align_start), align_size);
eb7d78c9 247 pgmap_radix_release(res);
4b94ffdc
DW
248 dev_WARN_ONCE(dev, pgmap->altmap && pgmap->altmap->alloc,
249 "%s: failed to free all reserved pages\n", __func__);
9476df7d
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250}
251
252/* assumes rcu_read_lock() held at entry */
253struct dev_pagemap *find_dev_pagemap(resource_size_t phys)
254{
255 struct page_map *page_map;
256
257 WARN_ON_ONCE(!rcu_read_lock_held());
258
259 page_map = radix_tree_lookup(&pgmap_radix, phys >> PA_SECTION_SHIFT);
260 return page_map ? &page_map->pgmap : NULL;
41e94a85
CH
261}
262
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DW
263/**
264 * devm_memremap_pages - remap and provide memmap backing for the given resource
265 * @dev: hosting device for @res
266 * @res: "host memory" address range
5c2c2587 267 * @ref: a live per-cpu reference count
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268 * @altmap: optional descriptor for allocating the memmap from @res
269 *
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270 * Notes:
271 * 1/ @ref must be 'live' on entry and 'dead' before devm_memunmap_pages() time
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272 * (or devm release event). The expected order of events is that @ref has
273 * been through percpu_ref_kill() before devm_memremap_pages_release(). The
274 * wait for the completion of all references being dropped and
275 * percpu_ref_exit() must occur after devm_memremap_pages_release().
5c2c2587
DW
276 *
277 * 2/ @res is expected to be a host memory range that could feasibly be
278 * treated as a "System RAM" range, i.e. not a device mmio range, but
279 * this is not enforced.
4b94ffdc
DW
280 */
281void *devm_memremap_pages(struct device *dev, struct resource *res,
5c2c2587 282 struct percpu_ref *ref, struct vmem_altmap *altmap)
41e94a85 283{
eb7d78c9 284 resource_size_t key, align_start, align_size, align_end;
9049771f 285 pgprot_t pgprot = PAGE_KERNEL;
4b94ffdc 286 struct dev_pagemap *pgmap;
41e94a85 287 struct page_map *page_map;
5f29a77c 288 int error, nid, is_ram;
5c2c2587 289 unsigned long pfn;
5f29a77c
DW
290
291 align_start = res->start & ~(SECTION_SIZE - 1);
292 align_size = ALIGN(res->start + resource_size(res), SECTION_SIZE)
293 - align_start;
d37a14bb
LT
294 is_ram = region_intersects(align_start, align_size,
295 IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE);
41e94a85
CH
296
297 if (is_ram == REGION_MIXED) {
298 WARN_ONCE(1, "%s attempted on mixed region %pr\n",
299 __func__, res);
300 return ERR_PTR(-ENXIO);
301 }
302
303 if (is_ram == REGION_INTERSECTS)
304 return __va(res->start);
305
5c2c2587
DW
306 if (!ref)
307 return ERR_PTR(-EINVAL);
308
538ea4aa
DW
309 page_map = devres_alloc_node(devm_memremap_pages_release,
310 sizeof(*page_map), GFP_KERNEL, dev_to_node(dev));
41e94a85
CH
311 if (!page_map)
312 return ERR_PTR(-ENOMEM);
4b94ffdc 313 pgmap = &page_map->pgmap;
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CH
314
315 memcpy(&page_map->res, res, sizeof(*res));
316
4b94ffdc
DW
317 pgmap->dev = dev;
318 if (altmap) {
319 memcpy(&page_map->altmap, altmap, sizeof(*altmap));
320 pgmap->altmap = &page_map->altmap;
321 }
5c2c2587 322 pgmap->ref = ref;
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DW
323 pgmap->res = &page_map->res;
324
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325 mutex_lock(&pgmap_lock);
326 error = 0;
eb7d78c9
DW
327 align_end = align_start + align_size - 1;
328 for (key = align_start; key <= align_end; key += SECTION_SIZE) {
9476df7d
DW
329 struct dev_pagemap *dup;
330
331 rcu_read_lock();
332 dup = find_dev_pagemap(key);
333 rcu_read_unlock();
334 if (dup) {
335 dev_err(dev, "%s: %pr collides with mapping for %s\n",
336 __func__, res, dev_name(dup->dev));
337 error = -EBUSY;
338 break;
339 }
340 error = radix_tree_insert(&pgmap_radix, key >> PA_SECTION_SHIFT,
341 page_map);
342 if (error) {
343 dev_err(dev, "%s: failed: %d\n", __func__, error);
344 break;
345 }
346 }
347 mutex_unlock(&pgmap_lock);
348 if (error)
349 goto err_radix;
350
41e94a85
CH
351 nid = dev_to_node(dev);
352 if (nid < 0)
7eff93b7 353 nid = numa_mem_id();
41e94a85 354
9049771f
DW
355 error = track_pfn_remap(NULL, &pgprot, PHYS_PFN(align_start), 0,
356 align_size);
357 if (error)
358 goto err_pfn_remap;
359
f931ab47 360 mem_hotplug_begin();
4fe85d5a 361 error = arch_add_memory(nid, align_start, align_size, true);
f931ab47 362 mem_hotplug_done();
9476df7d
DW
363 if (error)
364 goto err_add_memory;
41e94a85 365
5c2c2587
DW
366 for_each_device_pfn(pfn, page_map) {
367 struct page *page = pfn_to_page(pfn);
368
d77a117e
DW
369 /*
370 * ZONE_DEVICE pages union ->lru with a ->pgmap back
371 * pointer. It is a bug if a ZONE_DEVICE page is ever
372 * freed or placed on a driver-private list. Seed the
373 * storage with LIST_POISON* values.
374 */
375 list_del(&page->lru);
5c2c2587 376 page->pgmap = pgmap;
71389703 377 percpu_ref_get(ref);
5c2c2587 378 }
41e94a85
CH
379 devres_add(dev, page_map);
380 return __va(res->start);
9476df7d
DW
381
382 err_add_memory:
9049771f
DW
383 untrack_pfn(NULL, PHYS_PFN(align_start), align_size);
384 err_pfn_remap:
9476df7d
DW
385 err_radix:
386 pgmap_radix_release(res);
387 devres_free(page_map);
388 return ERR_PTR(error);
41e94a85
CH
389}
390EXPORT_SYMBOL(devm_memremap_pages);
4b94ffdc
DW
391
392unsigned long vmem_altmap_offset(struct vmem_altmap *altmap)
393{
394 /* number of pfns from base where pfn_to_page() is valid */
395 return altmap->reserve + altmap->free;
396}
397
398void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns)
399{
400 altmap->alloc -= nr_pfns;
401}
402
4b94ffdc
DW
403struct vmem_altmap *to_vmem_altmap(unsigned long memmap_start)
404{
405 /*
406 * 'memmap_start' is the virtual address for the first "struct
407 * page" in this range of the vmemmap array. In the case of
07061aab 408 * CONFIG_SPARSEMEM_VMEMMAP a page_to_pfn conversion is simple
4b94ffdc
DW
409 * pointer arithmetic, so we can perform this to_vmem_altmap()
410 * conversion without concern for the initialization state of
411 * the struct page fields.
412 */
413 struct page *page = (struct page *) memmap_start;
414 struct dev_pagemap *pgmap;
415
416 /*
07061aab 417 * Unconditionally retrieve a dev_pagemap associated with the
4b94ffdc
DW
418 * given physical address, this is only for use in the
419 * arch_{add|remove}_memory() for setting up and tearing down
420 * the memmap.
421 */
422 rcu_read_lock();
423 pgmap = find_dev_pagemap(__pfn_to_phys(page_to_pfn(page)));
424 rcu_read_unlock();
425
426 return pgmap ? pgmap->altmap : NULL;
427}
41e94a85 428#endif /* CONFIG_ZONE_DEVICE */