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5981690d DW |
1 | /* SPDX-License-Identifier: GPL-2.0 */ |
2 | /* Copyright(c) 2015 Intel Corporation. All rights reserved. */ | |
9476df7d | 3 | #include <linux/radix-tree.h> |
7d3dcf26 | 4 | #include <linux/device.h> |
92281dee | 5 | #include <linux/types.h> |
34c0fd54 | 6 | #include <linux/pfn_t.h> |
92281dee DW |
7 | #include <linux/io.h> |
8 | #include <linux/mm.h> | |
41e94a85 | 9 | #include <linux/memory_hotplug.h> |
5042db43 JG |
10 | #include <linux/swap.h> |
11 | #include <linux/swapops.h> | |
e7638488 | 12 | #include <linux/wait_bit.h> |
92281dee | 13 | |
9476df7d DW |
14 | static DEFINE_MUTEX(pgmap_lock); |
15 | static RADIX_TREE(pgmap_radix, GFP_KERNEL); | |
16 | #define SECTION_MASK ~((1UL << PA_SECTION_SHIFT) - 1) | |
17 | #define SECTION_SIZE (1UL << PA_SECTION_SHIFT) | |
18 | ||
ab1b597e | 19 | static unsigned long order_at(struct resource *res, unsigned long pgoff) |
9476df7d | 20 | { |
ab1b597e DW |
21 | unsigned long phys_pgoff = PHYS_PFN(res->start) + pgoff; |
22 | unsigned long nr_pages, mask; | |
eb7d78c9 | 23 | |
ab1b597e DW |
24 | nr_pages = PHYS_PFN(resource_size(res)); |
25 | if (nr_pages == pgoff) | |
26 | return ULONG_MAX; | |
27 | ||
28 | /* | |
29 | * What is the largest aligned power-of-2 range available from | |
30 | * this resource pgoff to the end of the resource range, | |
31 | * considering the alignment of the current pgoff? | |
32 | */ | |
33 | mask = phys_pgoff | rounddown_pow_of_two(nr_pages - pgoff); | |
34 | if (!mask) | |
35 | return ULONG_MAX; | |
36 | ||
37 | return find_first_bit(&mask, BITS_PER_LONG); | |
38 | } | |
39 | ||
40 | #define foreach_order_pgoff(res, order, pgoff) \ | |
41 | for (pgoff = 0, order = order_at((res), pgoff); order < ULONG_MAX; \ | |
42 | pgoff += 1UL << order, order = order_at((res), pgoff)) | |
43 | ||
5042db43 JG |
44 | #if IS_ENABLED(CONFIG_DEVICE_PRIVATE) |
45 | int device_private_entry_fault(struct vm_area_struct *vma, | |
46 | unsigned long addr, | |
47 | swp_entry_t entry, | |
48 | unsigned int flags, | |
49 | pmd_t *pmdp) | |
50 | { | |
51 | struct page *page = device_private_entry_to_page(entry); | |
52 | ||
53 | /* | |
54 | * The page_fault() callback must migrate page back to system memory | |
55 | * so that CPU can access it. This might fail for various reasons | |
56 | * (device issue, device was unsafely unplugged, ...). When such | |
57 | * error conditions happen, the callback must return VM_FAULT_SIGBUS. | |
58 | * | |
59 | * Note that because memory cgroup charges are accounted to the device | |
60 | * memory, this should never fail because of memory restrictions (but | |
61 | * allocation of regular system page might still fail because we are | |
62 | * out of memory). | |
63 | * | |
64 | * There is a more in-depth description of what that callback can and | |
65 | * cannot do, in include/linux/memremap.h | |
66 | */ | |
67 | return page->pgmap->page_fault(vma, addr, page, flags, pmdp); | |
68 | } | |
69 | EXPORT_SYMBOL(device_private_entry_fault); | |
70 | #endif /* CONFIG_DEVICE_PRIVATE */ | |
71 | ||
77dd66a3 | 72 | static void pgmap_radix_release(struct resource *res, unsigned long end_pgoff) |
ab1b597e DW |
73 | { |
74 | unsigned long pgoff, order; | |
9476df7d DW |
75 | |
76 | mutex_lock(&pgmap_lock); | |
77dd66a3 JS |
77 | foreach_order_pgoff(res, order, pgoff) { |
78 | if (pgoff >= end_pgoff) | |
79 | break; | |
ab1b597e | 80 | radix_tree_delete(&pgmap_radix, PHYS_PFN(res->start) + pgoff); |
77dd66a3 | 81 | } |
9476df7d | 82 | mutex_unlock(&pgmap_lock); |
ab1b597e DW |
83 | |
84 | synchronize_rcu(); | |
9476df7d DW |
85 | } |
86 | ||
e7744aa2 | 87 | static unsigned long pfn_first(struct dev_pagemap *pgmap) |
5c2c2587 | 88 | { |
e7744aa2 LG |
89 | const struct resource *res = &pgmap->res; |
90 | struct vmem_altmap *altmap = &pgmap->altmap; | |
5c2c2587 DW |
91 | unsigned long pfn; |
92 | ||
93 | pfn = res->start >> PAGE_SHIFT; | |
e7744aa2 | 94 | if (pgmap->altmap_valid) |
5c2c2587 DW |
95 | pfn += vmem_altmap_offset(altmap); |
96 | return pfn; | |
97 | } | |
98 | ||
e7744aa2 | 99 | static unsigned long pfn_end(struct dev_pagemap *pgmap) |
5c2c2587 | 100 | { |
e7744aa2 | 101 | const struct resource *res = &pgmap->res; |
5c2c2587 DW |
102 | |
103 | return (res->start + resource_size(res)) >> PAGE_SHIFT; | |
104 | } | |
105 | ||
949b9325 DW |
106 | static unsigned long pfn_next(unsigned long pfn) |
107 | { | |
108 | if (pfn % 1024 == 0) | |
109 | cond_resched(); | |
110 | return pfn + 1; | |
111 | } | |
112 | ||
5c2c2587 | 113 | #define for_each_device_pfn(pfn, map) \ |
949b9325 | 114 | for (pfn = pfn_first(map); pfn < pfn_end(map); pfn = pfn_next(pfn)) |
5c2c2587 | 115 | |
e8d51348 | 116 | static void devm_memremap_pages_release(void *data) |
41e94a85 | 117 | { |
e7744aa2 | 118 | struct dev_pagemap *pgmap = data; |
e8d51348 | 119 | struct device *dev = pgmap->dev; |
e7744aa2 | 120 | struct resource *res = &pgmap->res; |
9476df7d | 121 | resource_size_t align_start, align_size; |
71389703 DW |
122 | unsigned long pfn; |
123 | ||
e7744aa2 | 124 | for_each_device_pfn(pfn, pgmap) |
71389703 | 125 | put_page(pfn_to_page(pfn)); |
9476df7d | 126 | |
5c2c2587 DW |
127 | if (percpu_ref_tryget_live(pgmap->ref)) { |
128 | dev_WARN(dev, "%s: page mapping is still live!\n", __func__); | |
129 | percpu_ref_put(pgmap->ref); | |
130 | } | |
131 | ||
41e94a85 | 132 | /* pages are dead and unused, undo the arch mapping */ |
9476df7d | 133 | align_start = res->start & ~(SECTION_SIZE - 1); |
10a0cd6e JS |
134 | align_size = ALIGN(res->start + resource_size(res), SECTION_SIZE) |
135 | - align_start; | |
b5d24fda | 136 | |
f931ab47 | 137 | mem_hotplug_begin(); |
e7744aa2 LG |
138 | arch_remove_memory(align_start, align_size, pgmap->altmap_valid ? |
139 | &pgmap->altmap : NULL); | |
f931ab47 | 140 | mem_hotplug_done(); |
b5d24fda | 141 | |
9049771f | 142 | untrack_pfn(NULL, PHYS_PFN(align_start), align_size); |
77dd66a3 | 143 | pgmap_radix_release(res, -1); |
e7744aa2 LG |
144 | dev_WARN_ONCE(dev, pgmap->altmap.alloc, |
145 | "%s: failed to free all reserved pages\n", __func__); | |
9476df7d DW |
146 | } |
147 | ||
4b94ffdc DW |
148 | /** |
149 | * devm_memremap_pages - remap and provide memmap backing for the given resource | |
150 | * @dev: hosting device for @res | |
e8d51348 | 151 | * @pgmap: pointer to a struct dev_pgmap |
4b94ffdc | 152 | * |
5c2c2587 | 153 | * Notes: |
e8d51348 CH |
154 | * 1/ At a minimum the res, ref and type members of @pgmap must be initialized |
155 | * by the caller before passing it to this function | |
156 | * | |
157 | * 2/ The altmap field may optionally be initialized, in which case altmap_valid | |
158 | * must be set to true | |
159 | * | |
160 | * 3/ pgmap.ref must be 'live' on entry and 'dead' before devm_memunmap_pages() | |
161 | * time (or devm release event). The expected order of events is that ref has | |
71389703 DW |
162 | * been through percpu_ref_kill() before devm_memremap_pages_release(). The |
163 | * wait for the completion of all references being dropped and | |
164 | * percpu_ref_exit() must occur after devm_memremap_pages_release(). | |
5c2c2587 | 165 | * |
e8d51348 | 166 | * 4/ res is expected to be a host memory range that could feasibly be |
5c2c2587 DW |
167 | * treated as a "System RAM" range, i.e. not a device mmio range, but |
168 | * this is not enforced. | |
4b94ffdc | 169 | */ |
e8d51348 | 170 | void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap) |
41e94a85 | 171 | { |
ab1b597e | 172 | resource_size_t align_start, align_size, align_end; |
e8d51348 CH |
173 | struct vmem_altmap *altmap = pgmap->altmap_valid ? |
174 | &pgmap->altmap : NULL; | |
949b9325 | 175 | struct resource *res = &pgmap->res; |
ab1b597e | 176 | unsigned long pfn, pgoff, order; |
9049771f | 177 | pgprot_t pgprot = PAGE_KERNEL; |
949b9325 | 178 | int error, nid, is_ram; |
5f29a77c DW |
179 | |
180 | align_start = res->start & ~(SECTION_SIZE - 1); | |
181 | align_size = ALIGN(res->start + resource_size(res), SECTION_SIZE) | |
182 | - align_start; | |
d37a14bb LT |
183 | is_ram = region_intersects(align_start, align_size, |
184 | IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE); | |
41e94a85 CH |
185 | |
186 | if (is_ram == REGION_MIXED) { | |
187 | WARN_ONCE(1, "%s attempted on mixed region %pr\n", | |
188 | __func__, res); | |
189 | return ERR_PTR(-ENXIO); | |
190 | } | |
191 | ||
192 | if (is_ram == REGION_INTERSECTS) | |
193 | return __va(res->start); | |
194 | ||
e8d51348 | 195 | if (!pgmap->ref) |
5c2c2587 DW |
196 | return ERR_PTR(-EINVAL); |
197 | ||
4b94ffdc | 198 | pgmap->dev = dev; |
4b94ffdc | 199 | |
9476df7d DW |
200 | mutex_lock(&pgmap_lock); |
201 | error = 0; | |
eb7d78c9 | 202 | align_end = align_start + align_size - 1; |
ab1b597e DW |
203 | |
204 | foreach_order_pgoff(res, order, pgoff) { | |
ab1b597e | 205 | error = __radix_tree_insert(&pgmap_radix, |
e7744aa2 | 206 | PHYS_PFN(res->start) + pgoff, order, pgmap); |
9476df7d DW |
207 | if (error) { |
208 | dev_err(dev, "%s: failed: %d\n", __func__, error); | |
209 | break; | |
210 | } | |
211 | } | |
212 | mutex_unlock(&pgmap_lock); | |
213 | if (error) | |
214 | goto err_radix; | |
215 | ||
41e94a85 CH |
216 | nid = dev_to_node(dev); |
217 | if (nid < 0) | |
7eff93b7 | 218 | nid = numa_mem_id(); |
41e94a85 | 219 | |
9049771f DW |
220 | error = track_pfn_remap(NULL, &pgprot, PHYS_PFN(align_start), 0, |
221 | align_size); | |
222 | if (error) | |
223 | goto err_pfn_remap; | |
224 | ||
f931ab47 | 225 | mem_hotplug_begin(); |
24e6d5a5 | 226 | error = arch_add_memory(nid, align_start, align_size, altmap, false); |
f1dd2cd1 MH |
227 | if (!error) |
228 | move_pfn_range_to_zone(&NODE_DATA(nid)->node_zones[ZONE_DEVICE], | |
229 | align_start >> PAGE_SHIFT, | |
a99583e7 | 230 | align_size >> PAGE_SHIFT, altmap); |
f931ab47 | 231 | mem_hotplug_done(); |
9476df7d DW |
232 | if (error) |
233 | goto err_add_memory; | |
41e94a85 | 234 | |
e7744aa2 | 235 | for_each_device_pfn(pfn, pgmap) { |
5c2c2587 DW |
236 | struct page *page = pfn_to_page(pfn); |
237 | ||
d77a117e DW |
238 | /* |
239 | * ZONE_DEVICE pages union ->lru with a ->pgmap back | |
240 | * pointer. It is a bug if a ZONE_DEVICE page is ever | |
241 | * freed or placed on a driver-private list. Seed the | |
242 | * storage with LIST_POISON* values. | |
243 | */ | |
244 | list_del(&page->lru); | |
5c2c2587 | 245 | page->pgmap = pgmap; |
e8d51348 | 246 | percpu_ref_get(pgmap->ref); |
5c2c2587 | 247 | } |
e8d51348 CH |
248 | |
249 | devm_add_action(dev, devm_memremap_pages_release, pgmap); | |
250 | ||
41e94a85 | 251 | return __va(res->start); |
9476df7d DW |
252 | |
253 | err_add_memory: | |
9049771f DW |
254 | untrack_pfn(NULL, PHYS_PFN(align_start), align_size); |
255 | err_pfn_remap: | |
9476df7d | 256 | err_radix: |
77dd66a3 | 257 | pgmap_radix_release(res, pgoff); |
9476df7d | 258 | return ERR_PTR(error); |
41e94a85 CH |
259 | } |
260 | EXPORT_SYMBOL(devm_memremap_pages); | |
4b94ffdc DW |
261 | |
262 | unsigned long vmem_altmap_offset(struct vmem_altmap *altmap) | |
263 | { | |
264 | /* number of pfns from base where pfn_to_page() is valid */ | |
265 | return altmap->reserve + altmap->free; | |
266 | } | |
267 | ||
268 | void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns) | |
269 | { | |
270 | altmap->alloc -= nr_pfns; | |
271 | } | |
272 | ||
0822acb8 CH |
273 | /** |
274 | * get_dev_pagemap() - take a new live reference on the dev_pagemap for @pfn | |
275 | * @pfn: page frame number to lookup page_map | |
276 | * @pgmap: optional known pgmap that already has a reference | |
277 | * | |
832d7aa0 CH |
278 | * If @pgmap is non-NULL and covers @pfn it will be returned as-is. If @pgmap |
279 | * is non-NULL but does not cover @pfn the reference to it will be released. | |
0822acb8 CH |
280 | */ |
281 | struct dev_pagemap *get_dev_pagemap(unsigned long pfn, | |
282 | struct dev_pagemap *pgmap) | |
283 | { | |
0822acb8 CH |
284 | resource_size_t phys = PFN_PHYS(pfn); |
285 | ||
286 | /* | |
832d7aa0 | 287 | * In the cached case we're already holding a live reference. |
0822acb8 | 288 | */ |
832d7aa0 | 289 | if (pgmap) { |
e7744aa2 | 290 | if (phys >= pgmap->res.start && phys <= pgmap->res.end) |
832d7aa0 CH |
291 | return pgmap; |
292 | put_dev_pagemap(pgmap); | |
0822acb8 CH |
293 | } |
294 | ||
295 | /* fall back to slow path lookup */ | |
296 | rcu_read_lock(); | |
e697c5b9 | 297 | pgmap = radix_tree_lookup(&pgmap_radix, PHYS_PFN(phys)); |
0822acb8 CH |
298 | if (pgmap && !percpu_ref_tryget_live(pgmap->ref)) |
299 | pgmap = NULL; | |
300 | rcu_read_unlock(); | |
301 | ||
302 | return pgmap; | |
303 | } | |
e7638488 | 304 | EXPORT_SYMBOL_GPL(get_dev_pagemap); |
7b2d55d2 | 305 | |
e7638488 DW |
306 | #ifdef CONFIG_DEV_PAGEMAP_OPS |
307 | DEFINE_STATIC_KEY_FALSE(devmap_managed_key); | |
308 | EXPORT_SYMBOL_GPL(devmap_managed_key); | |
309 | static atomic_t devmap_enable; | |
310 | ||
311 | /* | |
312 | * Toggle the static key for ->page_free() callbacks when dev_pagemap | |
313 | * pages go idle. | |
314 | */ | |
315 | void dev_pagemap_get_ops(void) | |
316 | { | |
317 | if (atomic_inc_return(&devmap_enable) == 1) | |
318 | static_branch_enable(&devmap_managed_key); | |
319 | } | |
320 | EXPORT_SYMBOL_GPL(dev_pagemap_get_ops); | |
321 | ||
322 | void dev_pagemap_put_ops(void) | |
323 | { | |
324 | if (atomic_dec_and_test(&devmap_enable)) | |
325 | static_branch_disable(&devmap_managed_key); | |
326 | } | |
327 | EXPORT_SYMBOL_GPL(dev_pagemap_put_ops); | |
328 | ||
329 | void __put_devmap_managed_page(struct page *page) | |
7b2d55d2 JG |
330 | { |
331 | int count = page_ref_dec_return(page); | |
332 | ||
333 | /* | |
334 | * If refcount is 1 then page is freed and refcount is stable as nobody | |
335 | * holds a reference on the page. | |
336 | */ | |
337 | if (count == 1) { | |
338 | /* Clear Active bit in case of parallel mark_page_accessed */ | |
339 | __ClearPageActive(page); | |
340 | __ClearPageWaiters(page); | |
341 | ||
342 | page->mapping = NULL; | |
c733a828 | 343 | mem_cgroup_uncharge(page); |
7b2d55d2 JG |
344 | |
345 | page->pgmap->page_free(page, page->pgmap->data); | |
346 | } else if (!count) | |
347 | __put_page(page); | |
348 | } | |
e7638488 DW |
349 | EXPORT_SYMBOL_GPL(__put_devmap_managed_page); |
350 | #endif /* CONFIG_DEV_PAGEMAP_OPS */ |