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5981690d DW |
1 | /* SPDX-License-Identifier: GPL-2.0 */ |
2 | /* Copyright(c) 2015 Intel Corporation. All rights reserved. */ | |
7d3dcf26 | 3 | #include <linux/device.h> |
92281dee | 4 | #include <linux/io.h> |
0207df4f | 5 | #include <linux/kasan.h> |
41e94a85 | 6 | #include <linux/memory_hotplug.h> |
bcfa4b72 MW |
7 | #include <linux/mm.h> |
8 | #include <linux/pfn_t.h> | |
5042db43 JG |
9 | #include <linux/swap.h> |
10 | #include <linux/swapops.h> | |
bcfa4b72 | 11 | #include <linux/types.h> |
e7638488 | 12 | #include <linux/wait_bit.h> |
bcfa4b72 | 13 | #include <linux/xarray.h> |
92281dee | 14 | |
bcfa4b72 | 15 | static DEFINE_XARRAY(pgmap_array); |
9476df7d DW |
16 | #define SECTION_MASK ~((1UL << PA_SECTION_SHIFT) - 1) |
17 | #define SECTION_SIZE (1UL << PA_SECTION_SHIFT) | |
18 | ||
5042db43 | 19 | #if IS_ENABLED(CONFIG_DEVICE_PRIVATE) |
2b740303 | 20 | vm_fault_t device_private_entry_fault(struct vm_area_struct *vma, |
5042db43 JG |
21 | unsigned long addr, |
22 | swp_entry_t entry, | |
23 | unsigned int flags, | |
24 | pmd_t *pmdp) | |
25 | { | |
26 | struct page *page = device_private_entry_to_page(entry); | |
27 | ||
28 | /* | |
29 | * The page_fault() callback must migrate page back to system memory | |
30 | * so that CPU can access it. This might fail for various reasons | |
31 | * (device issue, device was unsafely unplugged, ...). When such | |
32 | * error conditions happen, the callback must return VM_FAULT_SIGBUS. | |
33 | * | |
34 | * Note that because memory cgroup charges are accounted to the device | |
35 | * memory, this should never fail because of memory restrictions (but | |
36 | * allocation of regular system page might still fail because we are | |
37 | * out of memory). | |
38 | * | |
39 | * There is a more in-depth description of what that callback can and | |
40 | * cannot do, in include/linux/memremap.h | |
41 | */ | |
42 | return page->pgmap->page_fault(vma, addr, page, flags, pmdp); | |
43 | } | |
44 | EXPORT_SYMBOL(device_private_entry_fault); | |
45 | #endif /* CONFIG_DEVICE_PRIVATE */ | |
46 | ||
bcfa4b72 | 47 | static void pgmap_array_delete(struct resource *res) |
ab1b597e | 48 | { |
bcfa4b72 MW |
49 | xa_store_range(&pgmap_array, PHYS_PFN(res->start), PHYS_PFN(res->end), |
50 | NULL, GFP_KERNEL); | |
ab1b597e | 51 | synchronize_rcu(); |
9476df7d DW |
52 | } |
53 | ||
e7744aa2 | 54 | static unsigned long pfn_first(struct dev_pagemap *pgmap) |
5c2c2587 | 55 | { |
e7744aa2 LG |
56 | const struct resource *res = &pgmap->res; |
57 | struct vmem_altmap *altmap = &pgmap->altmap; | |
5c2c2587 DW |
58 | unsigned long pfn; |
59 | ||
60 | pfn = res->start >> PAGE_SHIFT; | |
e7744aa2 | 61 | if (pgmap->altmap_valid) |
5c2c2587 DW |
62 | pfn += vmem_altmap_offset(altmap); |
63 | return pfn; | |
64 | } | |
65 | ||
e7744aa2 | 66 | static unsigned long pfn_end(struct dev_pagemap *pgmap) |
5c2c2587 | 67 | { |
e7744aa2 | 68 | const struct resource *res = &pgmap->res; |
5c2c2587 DW |
69 | |
70 | return (res->start + resource_size(res)) >> PAGE_SHIFT; | |
71 | } | |
72 | ||
949b9325 DW |
73 | static unsigned long pfn_next(unsigned long pfn) |
74 | { | |
75 | if (pfn % 1024 == 0) | |
76 | cond_resched(); | |
77 | return pfn + 1; | |
78 | } | |
79 | ||
5c2c2587 | 80 | #define for_each_device_pfn(pfn, map) \ |
949b9325 | 81 | for (pfn = pfn_first(map); pfn < pfn_end(map); pfn = pfn_next(pfn)) |
5c2c2587 | 82 | |
e8d51348 | 83 | static void devm_memremap_pages_release(void *data) |
41e94a85 | 84 | { |
e7744aa2 | 85 | struct dev_pagemap *pgmap = data; |
e8d51348 | 86 | struct device *dev = pgmap->dev; |
e7744aa2 | 87 | struct resource *res = &pgmap->res; |
9476df7d | 88 | resource_size_t align_start, align_size; |
71389703 DW |
89 | unsigned long pfn; |
90 | ||
e7744aa2 | 91 | for_each_device_pfn(pfn, pgmap) |
71389703 | 92 | put_page(pfn_to_page(pfn)); |
9476df7d | 93 | |
5c2c2587 DW |
94 | if (percpu_ref_tryget_live(pgmap->ref)) { |
95 | dev_WARN(dev, "%s: page mapping is still live!\n", __func__); | |
96 | percpu_ref_put(pgmap->ref); | |
97 | } | |
98 | ||
41e94a85 | 99 | /* pages are dead and unused, undo the arch mapping */ |
9476df7d | 100 | align_start = res->start & ~(SECTION_SIZE - 1); |
10a0cd6e JS |
101 | align_size = ALIGN(res->start + resource_size(res), SECTION_SIZE) |
102 | - align_start; | |
b5d24fda | 103 | |
f931ab47 | 104 | mem_hotplug_begin(); |
e7744aa2 LG |
105 | arch_remove_memory(align_start, align_size, pgmap->altmap_valid ? |
106 | &pgmap->altmap : NULL); | |
0207df4f | 107 | kasan_remove_zero_shadow(__va(align_start), align_size); |
f931ab47 | 108 | mem_hotplug_done(); |
b5d24fda | 109 | |
9049771f | 110 | untrack_pfn(NULL, PHYS_PFN(align_start), align_size); |
bcfa4b72 | 111 | pgmap_array_delete(res); |
e7744aa2 LG |
112 | dev_WARN_ONCE(dev, pgmap->altmap.alloc, |
113 | "%s: failed to free all reserved pages\n", __func__); | |
9476df7d DW |
114 | } |
115 | ||
4b94ffdc DW |
116 | /** |
117 | * devm_memremap_pages - remap and provide memmap backing for the given resource | |
118 | * @dev: hosting device for @res | |
e8d51348 | 119 | * @pgmap: pointer to a struct dev_pgmap |
4b94ffdc | 120 | * |
5c2c2587 | 121 | * Notes: |
e8d51348 CH |
122 | * 1/ At a minimum the res, ref and type members of @pgmap must be initialized |
123 | * by the caller before passing it to this function | |
124 | * | |
125 | * 2/ The altmap field may optionally be initialized, in which case altmap_valid | |
126 | * must be set to true | |
127 | * | |
128 | * 3/ pgmap.ref must be 'live' on entry and 'dead' before devm_memunmap_pages() | |
129 | * time (or devm release event). The expected order of events is that ref has | |
71389703 DW |
130 | * been through percpu_ref_kill() before devm_memremap_pages_release(). The |
131 | * wait for the completion of all references being dropped and | |
132 | * percpu_ref_exit() must occur after devm_memremap_pages_release(). | |
5c2c2587 | 133 | * |
e8d51348 | 134 | * 4/ res is expected to be a host memory range that could feasibly be |
5c2c2587 DW |
135 | * treated as a "System RAM" range, i.e. not a device mmio range, but |
136 | * this is not enforced. | |
4b94ffdc | 137 | */ |
e8d51348 | 138 | void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap) |
41e94a85 | 139 | { |
ab1b597e | 140 | resource_size_t align_start, align_size, align_end; |
e8d51348 CH |
141 | struct vmem_altmap *altmap = pgmap->altmap_valid ? |
142 | &pgmap->altmap : NULL; | |
949b9325 | 143 | struct resource *res = &pgmap->res; |
966cf44f | 144 | struct dev_pagemap *conflict_pgmap; |
9049771f | 145 | pgprot_t pgprot = PAGE_KERNEL; |
949b9325 | 146 | int error, nid, is_ram; |
5f29a77c DW |
147 | |
148 | align_start = res->start & ~(SECTION_SIZE - 1); | |
149 | align_size = ALIGN(res->start + resource_size(res), SECTION_SIZE) | |
150 | - align_start; | |
15d36fec DJ |
151 | align_end = align_start + align_size - 1; |
152 | ||
153 | conflict_pgmap = get_dev_pagemap(PHYS_PFN(align_start), NULL); | |
154 | if (conflict_pgmap) { | |
155 | dev_WARN(dev, "Conflicting mapping in same section\n"); | |
156 | put_dev_pagemap(conflict_pgmap); | |
157 | return ERR_PTR(-ENOMEM); | |
158 | } | |
159 | ||
160 | conflict_pgmap = get_dev_pagemap(PHYS_PFN(align_end), NULL); | |
161 | if (conflict_pgmap) { | |
162 | dev_WARN(dev, "Conflicting mapping in same section\n"); | |
163 | put_dev_pagemap(conflict_pgmap); | |
164 | return ERR_PTR(-ENOMEM); | |
165 | } | |
166 | ||
d37a14bb LT |
167 | is_ram = region_intersects(align_start, align_size, |
168 | IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE); | |
41e94a85 CH |
169 | |
170 | if (is_ram == REGION_MIXED) { | |
171 | WARN_ONCE(1, "%s attempted on mixed region %pr\n", | |
172 | __func__, res); | |
173 | return ERR_PTR(-ENXIO); | |
174 | } | |
175 | ||
176 | if (is_ram == REGION_INTERSECTS) | |
177 | return __va(res->start); | |
178 | ||
e8d51348 | 179 | if (!pgmap->ref) |
5c2c2587 DW |
180 | return ERR_PTR(-EINVAL); |
181 | ||
4b94ffdc | 182 | pgmap->dev = dev; |
4b94ffdc | 183 | |
bcfa4b72 MW |
184 | error = xa_err(xa_store_range(&pgmap_array, PHYS_PFN(res->start), |
185 | PHYS_PFN(res->end), pgmap, GFP_KERNEL)); | |
9476df7d | 186 | if (error) |
bcfa4b72 | 187 | goto err_array; |
9476df7d | 188 | |
41e94a85 CH |
189 | nid = dev_to_node(dev); |
190 | if (nid < 0) | |
7eff93b7 | 191 | nid = numa_mem_id(); |
41e94a85 | 192 | |
9049771f DW |
193 | error = track_pfn_remap(NULL, &pgprot, PHYS_PFN(align_start), 0, |
194 | align_size); | |
195 | if (error) | |
196 | goto err_pfn_remap; | |
197 | ||
f931ab47 | 198 | mem_hotplug_begin(); |
0207df4f AR |
199 | error = kasan_add_zero_shadow(__va(align_start), align_size); |
200 | if (error) { | |
201 | mem_hotplug_done(); | |
202 | goto err_kasan; | |
203 | } | |
204 | ||
24e6d5a5 | 205 | error = arch_add_memory(nid, align_start, align_size, altmap, false); |
f1dd2cd1 MH |
206 | if (!error) |
207 | move_pfn_range_to_zone(&NODE_DATA(nid)->node_zones[ZONE_DEVICE], | |
208 | align_start >> PAGE_SHIFT, | |
a99583e7 | 209 | align_size >> PAGE_SHIFT, altmap); |
f931ab47 | 210 | mem_hotplug_done(); |
9476df7d DW |
211 | if (error) |
212 | goto err_add_memory; | |
41e94a85 | 213 | |
966cf44f AD |
214 | /* |
215 | * Initialization of the pages has been deferred until now in order | |
216 | * to allow us to do the work while not holding the hotplug lock. | |
217 | */ | |
218 | memmap_init_zone_device(&NODE_DATA(nid)->node_zones[ZONE_DEVICE], | |
219 | align_start >> PAGE_SHIFT, | |
220 | align_size >> PAGE_SHIFT, pgmap); | |
221 | percpu_ref_get_many(pgmap->ref, pfn_end(pgmap) - pfn_first(pgmap)); | |
e8d51348 CH |
222 | |
223 | devm_add_action(dev, devm_memremap_pages_release, pgmap); | |
224 | ||
41e94a85 | 225 | return __va(res->start); |
9476df7d DW |
226 | |
227 | err_add_memory: | |
0207df4f AR |
228 | kasan_remove_zero_shadow(__va(align_start), align_size); |
229 | err_kasan: | |
9049771f DW |
230 | untrack_pfn(NULL, PHYS_PFN(align_start), align_size); |
231 | err_pfn_remap: | |
bcfa4b72 MW |
232 | pgmap_array_delete(res); |
233 | err_array: | |
9476df7d | 234 | return ERR_PTR(error); |
41e94a85 CH |
235 | } |
236 | EXPORT_SYMBOL(devm_memremap_pages); | |
4b94ffdc DW |
237 | |
238 | unsigned long vmem_altmap_offset(struct vmem_altmap *altmap) | |
239 | { | |
240 | /* number of pfns from base where pfn_to_page() is valid */ | |
241 | return altmap->reserve + altmap->free; | |
242 | } | |
243 | ||
244 | void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns) | |
245 | { | |
246 | altmap->alloc -= nr_pfns; | |
247 | } | |
248 | ||
0822acb8 CH |
249 | /** |
250 | * get_dev_pagemap() - take a new live reference on the dev_pagemap for @pfn | |
251 | * @pfn: page frame number to lookup page_map | |
252 | * @pgmap: optional known pgmap that already has a reference | |
253 | * | |
832d7aa0 CH |
254 | * If @pgmap is non-NULL and covers @pfn it will be returned as-is. If @pgmap |
255 | * is non-NULL but does not cover @pfn the reference to it will be released. | |
0822acb8 CH |
256 | */ |
257 | struct dev_pagemap *get_dev_pagemap(unsigned long pfn, | |
258 | struct dev_pagemap *pgmap) | |
259 | { | |
0822acb8 CH |
260 | resource_size_t phys = PFN_PHYS(pfn); |
261 | ||
262 | /* | |
832d7aa0 | 263 | * In the cached case we're already holding a live reference. |
0822acb8 | 264 | */ |
832d7aa0 | 265 | if (pgmap) { |
e7744aa2 | 266 | if (phys >= pgmap->res.start && phys <= pgmap->res.end) |
832d7aa0 CH |
267 | return pgmap; |
268 | put_dev_pagemap(pgmap); | |
0822acb8 CH |
269 | } |
270 | ||
271 | /* fall back to slow path lookup */ | |
272 | rcu_read_lock(); | |
bcfa4b72 | 273 | pgmap = xa_load(&pgmap_array, PHYS_PFN(phys)); |
0822acb8 CH |
274 | if (pgmap && !percpu_ref_tryget_live(pgmap->ref)) |
275 | pgmap = NULL; | |
276 | rcu_read_unlock(); | |
277 | ||
278 | return pgmap; | |
279 | } | |
e7638488 | 280 | EXPORT_SYMBOL_GPL(get_dev_pagemap); |
7b2d55d2 | 281 | |
e7638488 DW |
282 | #ifdef CONFIG_DEV_PAGEMAP_OPS |
283 | DEFINE_STATIC_KEY_FALSE(devmap_managed_key); | |
31c5bda3 | 284 | EXPORT_SYMBOL(devmap_managed_key); |
e7638488 DW |
285 | static atomic_t devmap_enable; |
286 | ||
287 | /* | |
288 | * Toggle the static key for ->page_free() callbacks when dev_pagemap | |
289 | * pages go idle. | |
290 | */ | |
291 | void dev_pagemap_get_ops(void) | |
292 | { | |
293 | if (atomic_inc_return(&devmap_enable) == 1) | |
294 | static_branch_enable(&devmap_managed_key); | |
295 | } | |
296 | EXPORT_SYMBOL_GPL(dev_pagemap_get_ops); | |
297 | ||
298 | void dev_pagemap_put_ops(void) | |
299 | { | |
300 | if (atomic_dec_and_test(&devmap_enable)) | |
301 | static_branch_disable(&devmap_managed_key); | |
302 | } | |
303 | EXPORT_SYMBOL_GPL(dev_pagemap_put_ops); | |
304 | ||
305 | void __put_devmap_managed_page(struct page *page) | |
7b2d55d2 JG |
306 | { |
307 | int count = page_ref_dec_return(page); | |
308 | ||
309 | /* | |
310 | * If refcount is 1 then page is freed and refcount is stable as nobody | |
311 | * holds a reference on the page. | |
312 | */ | |
313 | if (count == 1) { | |
314 | /* Clear Active bit in case of parallel mark_page_accessed */ | |
315 | __ClearPageActive(page); | |
316 | __ClearPageWaiters(page); | |
317 | ||
c733a828 | 318 | mem_cgroup_uncharge(page); |
7b2d55d2 JG |
319 | |
320 | page->pgmap->page_free(page, page->pgmap->data); | |
321 | } else if (!count) | |
322 | __put_page(page); | |
323 | } | |
31c5bda3 | 324 | EXPORT_SYMBOL(__put_devmap_managed_page); |
e7638488 | 325 | #endif /* CONFIG_DEV_PAGEMAP_OPS */ |