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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
31 static void *arch_memremap_wb(resource_size_t offset, unsigned long size)
32 {
33 return (__force void *)ioremap_cache(offset, size);
34 }
35 #endif
36
37 static 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 */
74 void *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 }
123 EXPORT_SYMBOL(memremap);
124
125 void memunmap(void *addr)
126 {
127 if (is_vmalloc_addr(addr))
128 iounmap((void __iomem *) addr);
129 }
130 EXPORT_SYMBOL(memunmap);
131
132 static void devm_memremap_release(struct device *dev, void *res)
133 {
134 memunmap(*(void **)res);
135 }
136
137 static int devm_memremap_match(struct device *dev, void *res, void *match_data)
138 {
139 return *(void **)res == match_data;
140 }
141
142 void *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 }
163 EXPORT_SYMBOL(devm_memremap);
164
165 void devm_memunmap(struct device *dev, void *addr)
166 {
167 WARN_ON(devres_release(dev, devm_memremap_release,
168 devm_memremap_match, addr));
169 }
170 EXPORT_SYMBOL(devm_memunmap);
171
172 #ifdef CONFIG_ZONE_DEVICE
173 static DEFINE_MUTEX(pgmap_lock);
174 static RADIX_TREE(pgmap_radix, GFP_KERNEL);
175 #define SECTION_MASK ~((1UL << PA_SECTION_SHIFT) - 1)
176 #define SECTION_SIZE (1UL << PA_SECTION_SHIFT)
177
178 struct page_map {
179 struct resource res;
180 struct percpu_ref *ref;
181 struct dev_pagemap pgmap;
182 struct vmem_altmap altmap;
183 };
184
185 static void pgmap_radix_release(struct resource *res)
186 {
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;
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
199 static 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
212 static 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
222 static void devm_memremap_pages_release(struct device *dev, void *data)
223 {
224 struct page_map *page_map = data;
225 struct resource *res = &page_map->res;
226 resource_size_t align_start, align_size;
227 struct dev_pagemap *pgmap = &page_map->pgmap;
228 unsigned long pfn;
229
230 for_each_device_pfn(pfn, page_map)
231 put_page(pfn_to_page(pfn));
232
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
238 /* pages are dead and unused, undo the arch mapping */
239 align_start = res->start & ~(SECTION_SIZE - 1);
240 align_size = ALIGN(resource_size(res), SECTION_SIZE);
241
242 mem_hotplug_begin();
243 arch_remove_memory(align_start, align_size);
244 mem_hotplug_done();
245
246 untrack_pfn(NULL, PHYS_PFN(align_start), align_size);
247 pgmap_radix_release(res);
248 dev_WARN_ONCE(dev, pgmap->altmap && pgmap->altmap->alloc,
249 "%s: failed to free all reserved pages\n", __func__);
250 }
251
252 /* assumes rcu_read_lock() held at entry */
253 struct 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;
261 }
262
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
267 * @ref: a live per-cpu reference count
268 * @altmap: optional descriptor for allocating the memmap from @res
269 *
270 * Notes:
271 * 1/ @ref must be 'live' on entry and 'dead' before devm_memunmap_pages() time
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().
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.
280 */
281 void *devm_memremap_pages(struct device *dev, struct resource *res,
282 struct percpu_ref *ref, struct vmem_altmap *altmap)
283 {
284 resource_size_t key, align_start, align_size, align_end;
285 pgprot_t pgprot = PAGE_KERNEL;
286 struct dev_pagemap *pgmap;
287 struct page_map *page_map;
288 int error, nid, is_ram;
289 unsigned long pfn;
290
291 align_start = res->start & ~(SECTION_SIZE - 1);
292 align_size = ALIGN(res->start + resource_size(res), SECTION_SIZE)
293 - align_start;
294 is_ram = region_intersects(align_start, align_size,
295 IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE);
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
306 if (!ref)
307 return ERR_PTR(-EINVAL);
308
309 page_map = devres_alloc_node(devm_memremap_pages_release,
310 sizeof(*page_map), GFP_KERNEL, dev_to_node(dev));
311 if (!page_map)
312 return ERR_PTR(-ENOMEM);
313 pgmap = &page_map->pgmap;
314
315 memcpy(&page_map->res, res, sizeof(*res));
316
317 pgmap->dev = dev;
318 if (altmap) {
319 memcpy(&page_map->altmap, altmap, sizeof(*altmap));
320 pgmap->altmap = &page_map->altmap;
321 }
322 pgmap->ref = ref;
323 pgmap->res = &page_map->res;
324
325 mutex_lock(&pgmap_lock);
326 error = 0;
327 align_end = align_start + align_size - 1;
328 for (key = align_start; key <= align_end; key += SECTION_SIZE) {
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
351 nid = dev_to_node(dev);
352 if (nid < 0)
353 nid = numa_mem_id();
354
355 error = track_pfn_remap(NULL, &pgprot, PHYS_PFN(align_start), 0,
356 align_size);
357 if (error)
358 goto err_pfn_remap;
359
360 mem_hotplug_begin();
361 error = arch_add_memory(nid, align_start, align_size, true);
362 mem_hotplug_done();
363 if (error)
364 goto err_add_memory;
365
366 for_each_device_pfn(pfn, page_map) {
367 struct page *page = pfn_to_page(pfn);
368
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);
376 page->pgmap = pgmap;
377 percpu_ref_get(ref);
378 }
379 devres_add(dev, page_map);
380 return __va(res->start);
381
382 err_add_memory:
383 untrack_pfn(NULL, PHYS_PFN(align_start), align_size);
384 err_pfn_remap:
385 err_radix:
386 pgmap_radix_release(res);
387 devres_free(page_map);
388 return ERR_PTR(error);
389 }
390 EXPORT_SYMBOL(devm_memremap_pages);
391
392 unsigned 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
398 void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns)
399 {
400 altmap->alloc -= nr_pfns;
401 }
402
403 struct 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
408 * CONFIG_SPARSEMEM_VMEMMAP a page_to_pfn conversion is simple
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 /*
417 * Unconditionally retrieve a dev_pagemap associated with the
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 }
428 #endif /* CONFIG_ZONE_DEVICE */