2 * Copyright(c) 2015 Intel Corporation. All rights reserved.
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.
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.
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>
20 #include <linux/memory_hotplug.h>
23 /* temporary while we convert existing ioremap_cache users to memremap */
24 __weak
void __iomem
*ioremap_cache(resource_size_t offset
, unsigned long size
)
26 return ioremap(offset
, size
);
30 #ifndef arch_memremap_wb
31 static void *arch_memremap_wb(resource_size_t offset
, unsigned long size
)
33 return (__force
void *)ioremap_cache(offset
, size
);
37 #ifndef arch_memremap_can_ram_remap
38 static bool arch_memremap_can_ram_remap(resource_size_t offset
, size_t size
,
45 static void *try_ram_remap(resource_size_t offset
, size_t size
,
48 unsigned long pfn
= PHYS_PFN(offset
);
50 /* In the simple case just return the existing linear address */
51 if (pfn_valid(pfn
) && !PageHighMem(pfn_to_page(pfn
)) &&
52 arch_memremap_can_ram_remap(offset
, size
, flags
))
55 return NULL
; /* fallback to arch_memremap_wb */
59 * memremap() - remap an iomem_resource as cacheable memory
60 * @offset: iomem resource start address
61 * @size: size of remap
62 * @flags: any of MEMREMAP_WB, MEMREMAP_WT, MEMREMAP_WC,
63 * MEMREMAP_ENC, MEMREMAP_DEC
65 * memremap() is "ioremap" for cases where it is known that the resource
66 * being mapped does not have i/o side effects and the __iomem
67 * annotation is not applicable. In the case of multiple flags, the different
68 * mapping types will be attempted in the order listed below until one of
71 * MEMREMAP_WB - matches the default mapping for System RAM on
72 * the architecture. This is usually a read-allocate write-back cache.
73 * Morever, if MEMREMAP_WB is specified and the requested remap region is RAM
74 * memremap() will bypass establishing a new mapping and instead return
75 * a pointer into the direct map.
77 * MEMREMAP_WT - establish a mapping whereby writes either bypass the
78 * cache or are written through to memory and never exist in a
79 * cache-dirty state with respect to program visibility. Attempts to
80 * map System RAM with this mapping type will fail.
82 * MEMREMAP_WC - establish a writecombine mapping, whereby writes may
83 * be coalesced together (e.g. in the CPU's write buffers), but is otherwise
84 * uncached. Attempts to map System RAM with this mapping type will fail.
86 void *memremap(resource_size_t offset
, size_t size
, unsigned long flags
)
88 int is_ram
= region_intersects(offset
, size
,
89 IORESOURCE_SYSTEM_RAM
, IORES_DESC_NONE
);
95 if (is_ram
== REGION_MIXED
) {
96 WARN_ONCE(1, "memremap attempted on mixed range %pa size: %#lx\n",
97 &offset
, (unsigned long) size
);
101 /* Try all mapping types requested until one returns non-NULL */
102 if (flags
& MEMREMAP_WB
) {
104 * MEMREMAP_WB is special in that it can be satisifed
105 * from the direct map. Some archs depend on the
106 * capability of memremap() to autodetect cases where
107 * the requested range is potentially in System RAM.
109 if (is_ram
== REGION_INTERSECTS
)
110 addr
= try_ram_remap(offset
, size
, flags
);
112 addr
= arch_memremap_wb(offset
, size
);
116 * If we don't have a mapping yet and other request flags are
117 * present then we will be attempting to establish a new virtual
118 * address mapping. Enforce that this mapping is not aliasing
121 if (!addr
&& is_ram
== REGION_INTERSECTS
&& flags
!= MEMREMAP_WB
) {
122 WARN_ONCE(1, "memremap attempted on ram %pa size: %#lx\n",
123 &offset
, (unsigned long) size
);
127 if (!addr
&& (flags
& MEMREMAP_WT
))
128 addr
= ioremap_wt(offset
, size
);
130 if (!addr
&& (flags
& MEMREMAP_WC
))
131 addr
= ioremap_wc(offset
, size
);
135 EXPORT_SYMBOL(memremap
);
137 void memunmap(void *addr
)
139 if (is_vmalloc_addr(addr
))
140 iounmap((void __iomem
*) addr
);
142 EXPORT_SYMBOL(memunmap
);
144 static void devm_memremap_release(struct device
*dev
, void *res
)
146 memunmap(*(void **)res
);
149 static int devm_memremap_match(struct device
*dev
, void *res
, void *match_data
)
151 return *(void **)res
== match_data
;
154 void *devm_memremap(struct device
*dev
, resource_size_t offset
,
155 size_t size
, unsigned long flags
)
159 ptr
= devres_alloc_node(devm_memremap_release
, sizeof(*ptr
), GFP_KERNEL
,
162 return ERR_PTR(-ENOMEM
);
164 addr
= memremap(offset
, size
, flags
);
167 devres_add(dev
, ptr
);
170 return ERR_PTR(-ENXIO
);
175 EXPORT_SYMBOL(devm_memremap
);
177 void devm_memunmap(struct device
*dev
, void *addr
)
179 WARN_ON(devres_release(dev
, devm_memremap_release
,
180 devm_memremap_match
, addr
));
182 EXPORT_SYMBOL(devm_memunmap
);
184 #ifdef CONFIG_ZONE_DEVICE
185 static DEFINE_MUTEX(pgmap_lock
);
186 static RADIX_TREE(pgmap_radix
, GFP_KERNEL
);
187 #define SECTION_MASK ~((1UL << PA_SECTION_SHIFT) - 1)
188 #define SECTION_SIZE (1UL << PA_SECTION_SHIFT)
192 struct percpu_ref
*ref
;
193 struct dev_pagemap pgmap
;
194 struct vmem_altmap altmap
;
197 static unsigned long order_at(struct resource
*res
, unsigned long pgoff
)
199 unsigned long phys_pgoff
= PHYS_PFN(res
->start
) + pgoff
;
200 unsigned long nr_pages
, mask
;
202 nr_pages
= PHYS_PFN(resource_size(res
));
203 if (nr_pages
== pgoff
)
207 * What is the largest aligned power-of-2 range available from
208 * this resource pgoff to the end of the resource range,
209 * considering the alignment of the current pgoff?
211 mask
= phys_pgoff
| rounddown_pow_of_two(nr_pages
- pgoff
);
215 return find_first_bit(&mask
, BITS_PER_LONG
);
218 #define foreach_order_pgoff(res, order, pgoff) \
219 for (pgoff = 0, order = order_at((res), pgoff); order < ULONG_MAX; \
220 pgoff += 1UL << order, order = order_at((res), pgoff))
222 static void pgmap_radix_release(struct resource
*res
)
224 unsigned long pgoff
, order
;
226 mutex_lock(&pgmap_lock
);
227 foreach_order_pgoff(res
, order
, pgoff
)
228 radix_tree_delete(&pgmap_radix
, PHYS_PFN(res
->start
) + pgoff
);
229 mutex_unlock(&pgmap_lock
);
234 static unsigned long pfn_first(struct page_map
*page_map
)
236 struct dev_pagemap
*pgmap
= &page_map
->pgmap
;
237 const struct resource
*res
= &page_map
->res
;
238 struct vmem_altmap
*altmap
= pgmap
->altmap
;
241 pfn
= res
->start
>> PAGE_SHIFT
;
243 pfn
+= vmem_altmap_offset(altmap
);
247 static unsigned long pfn_end(struct page_map
*page_map
)
249 const struct resource
*res
= &page_map
->res
;
251 return (res
->start
+ resource_size(res
)) >> PAGE_SHIFT
;
254 #define for_each_device_pfn(pfn, map) \
255 for (pfn = pfn_first(map); pfn < pfn_end(map); pfn++)
257 static void devm_memremap_pages_release(struct device
*dev
, void *data
)
259 struct page_map
*page_map
= data
;
260 struct resource
*res
= &page_map
->res
;
261 resource_size_t align_start
, align_size
;
262 struct dev_pagemap
*pgmap
= &page_map
->pgmap
;
265 for_each_device_pfn(pfn
, page_map
)
266 put_page(pfn_to_page(pfn
));
268 if (percpu_ref_tryget_live(pgmap
->ref
)) {
269 dev_WARN(dev
, "%s: page mapping is still live!\n", __func__
);
270 percpu_ref_put(pgmap
->ref
);
273 /* pages are dead and unused, undo the arch mapping */
274 align_start
= res
->start
& ~(SECTION_SIZE
- 1);
275 align_size
= ALIGN(resource_size(res
), SECTION_SIZE
);
278 arch_remove_memory(align_start
, align_size
);
281 untrack_pfn(NULL
, PHYS_PFN(align_start
), align_size
);
282 pgmap_radix_release(res
);
283 dev_WARN_ONCE(dev
, pgmap
->altmap
&& pgmap
->altmap
->alloc
,
284 "%s: failed to free all reserved pages\n", __func__
);
287 /* assumes rcu_read_lock() held at entry */
288 struct dev_pagemap
*find_dev_pagemap(resource_size_t phys
)
290 struct page_map
*page_map
;
292 WARN_ON_ONCE(!rcu_read_lock_held());
294 page_map
= radix_tree_lookup(&pgmap_radix
, PHYS_PFN(phys
));
295 return page_map
? &page_map
->pgmap
: NULL
;
299 * devm_memremap_pages - remap and provide memmap backing for the given resource
300 * @dev: hosting device for @res
301 * @res: "host memory" address range
302 * @ref: a live per-cpu reference count
303 * @altmap: optional descriptor for allocating the memmap from @res
306 * 1/ @ref must be 'live' on entry and 'dead' before devm_memunmap_pages() time
307 * (or devm release event). The expected order of events is that @ref has
308 * been through percpu_ref_kill() before devm_memremap_pages_release(). The
309 * wait for the completion of all references being dropped and
310 * percpu_ref_exit() must occur after devm_memremap_pages_release().
312 * 2/ @res is expected to be a host memory range that could feasibly be
313 * treated as a "System RAM" range, i.e. not a device mmio range, but
314 * this is not enforced.
316 void *devm_memremap_pages(struct device
*dev
, struct resource
*res
,
317 struct percpu_ref
*ref
, struct vmem_altmap
*altmap
)
319 resource_size_t align_start
, align_size
, align_end
;
320 unsigned long pfn
, pgoff
, order
;
321 pgprot_t pgprot
= PAGE_KERNEL
;
322 struct dev_pagemap
*pgmap
;
323 struct page_map
*page_map
;
324 int error
, nid
, is_ram
;
326 align_start
= res
->start
& ~(SECTION_SIZE
- 1);
327 align_size
= ALIGN(res
->start
+ resource_size(res
), SECTION_SIZE
)
329 is_ram
= region_intersects(align_start
, align_size
,
330 IORESOURCE_SYSTEM_RAM
, IORES_DESC_NONE
);
332 if (is_ram
== REGION_MIXED
) {
333 WARN_ONCE(1, "%s attempted on mixed region %pr\n",
335 return ERR_PTR(-ENXIO
);
338 if (is_ram
== REGION_INTERSECTS
)
339 return __va(res
->start
);
342 return ERR_PTR(-EINVAL
);
344 page_map
= devres_alloc_node(devm_memremap_pages_release
,
345 sizeof(*page_map
), GFP_KERNEL
, dev_to_node(dev
));
347 return ERR_PTR(-ENOMEM
);
348 pgmap
= &page_map
->pgmap
;
350 memcpy(&page_map
->res
, res
, sizeof(*res
));
354 memcpy(&page_map
->altmap
, altmap
, sizeof(*altmap
));
355 pgmap
->altmap
= &page_map
->altmap
;
358 pgmap
->res
= &page_map
->res
;
360 mutex_lock(&pgmap_lock
);
362 align_end
= align_start
+ align_size
- 1;
364 foreach_order_pgoff(res
, order
, pgoff
) {
365 struct dev_pagemap
*dup
;
368 dup
= find_dev_pagemap(res
->start
+ PFN_PHYS(pgoff
));
371 dev_err(dev
, "%s: %pr collides with mapping for %s\n",
372 __func__
, res
, dev_name(dup
->dev
));
376 error
= __radix_tree_insert(&pgmap_radix
,
377 PHYS_PFN(res
->start
) + pgoff
, order
, page_map
);
379 dev_err(dev
, "%s: failed: %d\n", __func__
, error
);
383 mutex_unlock(&pgmap_lock
);
387 nid
= dev_to_node(dev
);
391 error
= track_pfn_remap(NULL
, &pgprot
, PHYS_PFN(align_start
), 0,
397 error
= arch_add_memory(nid
, align_start
, align_size
, false);
399 move_pfn_range_to_zone(&NODE_DATA(nid
)->node_zones
[ZONE_DEVICE
],
400 align_start
>> PAGE_SHIFT
,
401 align_size
>> PAGE_SHIFT
);
406 for_each_device_pfn(pfn
, page_map
) {
407 struct page
*page
= pfn_to_page(pfn
);
410 * ZONE_DEVICE pages union ->lru with a ->pgmap back
411 * pointer. It is a bug if a ZONE_DEVICE page is ever
412 * freed or placed on a driver-private list. Seed the
413 * storage with LIST_POISON* values.
415 list_del(&page
->lru
);
419 devres_add(dev
, page_map
);
420 return __va(res
->start
);
423 untrack_pfn(NULL
, PHYS_PFN(align_start
), align_size
);
426 pgmap_radix_release(res
);
427 devres_free(page_map
);
428 return ERR_PTR(error
);
430 EXPORT_SYMBOL(devm_memremap_pages
);
432 unsigned long vmem_altmap_offset(struct vmem_altmap
*altmap
)
434 /* number of pfns from base where pfn_to_page() is valid */
435 return altmap
->reserve
+ altmap
->free
;
438 void vmem_altmap_free(struct vmem_altmap
*altmap
, unsigned long nr_pfns
)
440 altmap
->alloc
-= nr_pfns
;
443 struct vmem_altmap
*to_vmem_altmap(unsigned long memmap_start
)
446 * 'memmap_start' is the virtual address for the first "struct
447 * page" in this range of the vmemmap array. In the case of
448 * CONFIG_SPARSEMEM_VMEMMAP a page_to_pfn conversion is simple
449 * pointer arithmetic, so we can perform this to_vmem_altmap()
450 * conversion without concern for the initialization state of
451 * the struct page fields.
453 struct page
*page
= (struct page
*) memmap_start
;
454 struct dev_pagemap
*pgmap
;
457 * Unconditionally retrieve a dev_pagemap associated with the
458 * given physical address, this is only for use in the
459 * arch_{add|remove}_memory() for setting up and tearing down
463 pgmap
= find_dev_pagemap(__pfn_to_phys(page_to_pfn(page
)));
466 return pgmap
? pgmap
->altmap
: NULL
;
468 #endif /* CONFIG_ZONE_DEVICE */