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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
9476df7d DW |
2 | #ifndef _LINUX_MEMREMAP_H_ |
3 | #define _LINUX_MEMREMAP_H_ | |
dc90f084 CH |
4 | |
5 | #include <linux/mm.h> | |
a4574f63 | 6 | #include <linux/range.h> |
5c2c2587 DW |
7 | #include <linux/ioport.h> |
8 | #include <linux/percpu-refcount.h> | |
9476df7d DW |
9 | |
10 | struct resource; | |
11 | struct device; | |
4b94ffdc DW |
12 | |
13 | /** | |
14 | * struct vmem_altmap - pre-allocated storage for vmemmap_populate | |
15 | * @base_pfn: base of the entire dev_pagemap mapping | |
16 | * @reserve: pages mapped, but reserved for driver use (relative to @base) | |
17 | * @free: free pages set aside in the mapping for memmap storage | |
18 | * @align: pages reserved to meet allocation alignments | |
19 | * @alloc: track pages consumed, private to vmemmap_populate() | |
20 | */ | |
21 | struct vmem_altmap { | |
a08a2ae3 | 22 | unsigned long base_pfn; |
cf387d96 | 23 | const unsigned long end_pfn; |
4b94ffdc DW |
24 | const unsigned long reserve; |
25 | unsigned long free; | |
26 | unsigned long align; | |
27 | unsigned long alloc; | |
28 | }; | |
29 | ||
5042db43 | 30 | /* |
041711ce | 31 | * Specialize ZONE_DEVICE memory into multiple types each has a different |
5042db43 JG |
32 | * usage. |
33 | * | |
5042db43 JG |
34 | * MEMORY_DEVICE_PRIVATE: |
35 | * Device memory that is not directly addressable by the CPU: CPU can neither | |
36 | * read nor write private memory. In this case, we do still have struct pages | |
37 | * backing the device memory. Doing so simplifies the implementation, but it is | |
38 | * important to remember that there are certain points at which the struct page | |
39 | * must be treated as an opaque object, rather than a "normal" struct page. | |
40 | * | |
41 | * A more complete discussion of unaddressable memory may be found in | |
ad56b738 | 42 | * include/linux/hmm.h and Documentation/vm/hmm.rst. |
df6ad698 | 43 | * |
e7638488 DW |
44 | * MEMORY_DEVICE_FS_DAX: |
45 | * Host memory that has similar access semantics as System RAM i.e. DMA | |
46 | * coherent and supports page pinning. In support of coordinating page | |
47 | * pinning vs other operations MEMORY_DEVICE_FS_DAX arranges for a | |
48 | * wakeup event whenever a page is unpinned and becomes idle. This | |
49 | * wakeup is used to coordinate physical address space management (ex: | |
50 | * fs truncate/hole punch) vs pinned pages (ex: device dma). | |
52916982 | 51 | * |
4533d3ae | 52 | * MEMORY_DEVICE_GENERIC: |
3ed2dcdf | 53 | * Host memory that has similar access semantics as System RAM i.e. DMA |
4533d3ae RPM |
54 | * coherent and supports page pinning. This is for example used by DAX devices |
55 | * that expose memory using a character device. | |
3ed2dcdf | 56 | * |
52916982 LG |
57 | * MEMORY_DEVICE_PCI_P2PDMA: |
58 | * Device memory residing in a PCI BAR intended for use with Peer-to-Peer | |
59 | * transactions. | |
5042db43 JG |
60 | */ |
61 | enum memory_type { | |
3ed2dcdf | 62 | /* 0 is reserved to catch uninitialized type fields */ |
e7638488 | 63 | MEMORY_DEVICE_PRIVATE = 1, |
e7638488 | 64 | MEMORY_DEVICE_FS_DAX, |
4533d3ae | 65 | MEMORY_DEVICE_GENERIC, |
52916982 | 66 | MEMORY_DEVICE_PCI_P2PDMA, |
5042db43 JG |
67 | }; |
68 | ||
1e240e8d CH |
69 | struct dev_pagemap_ops { |
70 | /* | |
27674ef6 CH |
71 | * Called once the page refcount reaches 0. The reference count will be |
72 | * reset to one by the core code after the method is called to prepare | |
73 | * for handing out the page again. | |
1e240e8d | 74 | */ |
80a72d0a | 75 | void (*page_free)(struct page *page); |
1e240e8d | 76 | |
897e6365 CH |
77 | /* |
78 | * Used for private (un-addressable) device memory only. Must migrate | |
79 | * the page back to a CPU accessible page. | |
80 | */ | |
81 | vm_fault_t (*migrate_to_ram)(struct vm_fault *vmf); | |
1e240e8d | 82 | }; |
5042db43 | 83 | |
514caf23 CH |
84 | #define PGMAP_ALTMAP_VALID (1 << 0) |
85 | ||
9476df7d DW |
86 | /** |
87 | * struct dev_pagemap - metadata for ZONE_DEVICE mappings | |
4b94ffdc | 88 | * @altmap: pre-allocated/reserved memory for vmemmap allocations |
5c2c2587 | 89 | * @ref: reference count that pins the devm_memremap_pages() mapping |
b80892ca | 90 | * @done: completion for @ref |
5042db43 | 91 | * @type: memory type: see MEMORY_* in memory_hotplug.h |
514caf23 | 92 | * @flags: PGMAP_* flags to specify defailed behavior |
c4386bd8 JM |
93 | * @vmemmap_shift: structural definition of how the vmemmap page metadata |
94 | * is populated, specifically the metadata page order. | |
95 | * A zero value (default) uses base pages as the vmemmap metadata | |
96 | * representation. A bigger value will set up compound struct pages | |
97 | * of the requested order value. | |
1e240e8d | 98 | * @ops: method table |
f894ddd5 CH |
99 | * @owner: an opaque pointer identifying the entity that manages this |
100 | * instance. Used by various helpers to make sure that no | |
101 | * foreign ZONE_DEVICE memory is accessed. | |
b7b3c01b DW |
102 | * @nr_range: number of ranges to be mapped |
103 | * @range: range to be mapped when nr_range == 1 | |
104 | * @ranges: array of ranges to be mapped when nr_range > 1 | |
9476df7d DW |
105 | */ |
106 | struct dev_pagemap { | |
e7744aa2 | 107 | struct vmem_altmap altmap; |
b80892ca | 108 | struct percpu_ref ref; |
24917f6b | 109 | struct completion done; |
5042db43 | 110 | enum memory_type type; |
514caf23 | 111 | unsigned int flags; |
c4386bd8 | 112 | unsigned long vmemmap_shift; |
1e240e8d | 113 | const struct dev_pagemap_ops *ops; |
f894ddd5 | 114 | void *owner; |
b7b3c01b DW |
115 | int nr_range; |
116 | union { | |
117 | struct range range; | |
118 | struct range ranges[0]; | |
119 | }; | |
9476df7d DW |
120 | }; |
121 | ||
514caf23 CH |
122 | static inline struct vmem_altmap *pgmap_altmap(struct dev_pagemap *pgmap) |
123 | { | |
124 | if (pgmap->flags & PGMAP_ALTMAP_VALID) | |
125 | return &pgmap->altmap; | |
126 | return NULL; | |
127 | } | |
128 | ||
c4386bd8 JM |
129 | static inline unsigned long pgmap_vmemmap_nr(struct dev_pagemap *pgmap) |
130 | { | |
131 | return 1 << pgmap->vmemmap_shift; | |
132 | } | |
133 | ||
dc90f084 CH |
134 | static inline bool is_device_private_page(const struct page *page) |
135 | { | |
27674ef6 | 136 | return IS_ENABLED(CONFIG_DEVICE_PRIVATE) && |
dc90f084 CH |
137 | is_zone_device_page(page) && |
138 | page->pgmap->type == MEMORY_DEVICE_PRIVATE; | |
139 | } | |
140 | ||
536939ff MWO |
141 | static inline bool folio_is_device_private(const struct folio *folio) |
142 | { | |
143 | return is_device_private_page(&folio->page); | |
144 | } | |
145 | ||
dc90f084 CH |
146 | static inline bool is_pci_p2pdma_page(const struct page *page) |
147 | { | |
27674ef6 | 148 | return IS_ENABLED(CONFIG_PCI_P2PDMA) && |
dc90f084 CH |
149 | is_zone_device_page(page) && |
150 | page->pgmap->type == MEMORY_DEVICE_PCI_P2PDMA; | |
151 | } | |
152 | ||
9476df7d | 153 | #ifdef CONFIG_ZONE_DEVICE |
6869b7b2 CH |
154 | void *memremap_pages(struct dev_pagemap *pgmap, int nid); |
155 | void memunmap_pages(struct dev_pagemap *pgmap); | |
e8d51348 | 156 | void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap); |
2e3f139e | 157 | void devm_memunmap_pages(struct device *dev, struct dev_pagemap *pgmap); |
0822acb8 CH |
158 | struct dev_pagemap *get_dev_pagemap(unsigned long pfn, |
159 | struct dev_pagemap *pgmap); | |
34dc45be | 160 | bool pgmap_pfn_valid(struct dev_pagemap *pgmap, unsigned long pfn); |
7b2d55d2 | 161 | |
8e37d00a CH |
162 | unsigned long vmem_altmap_offset(struct vmem_altmap *altmap); |
163 | void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns); | |
9ffc1d19 | 164 | unsigned long memremap_compat_align(void); |
9476df7d DW |
165 | #else |
166 | static inline void *devm_memremap_pages(struct device *dev, | |
e8d51348 | 167 | struct dev_pagemap *pgmap) |
9476df7d DW |
168 | { |
169 | /* | |
170 | * Fail attempts to call devm_memremap_pages() without | |
171 | * ZONE_DEVICE support enabled, this requires callers to fall | |
172 | * back to plain devm_memremap() based on config | |
173 | */ | |
174 | WARN_ON_ONCE(1); | |
175 | return ERR_PTR(-ENXIO); | |
176 | } | |
177 | ||
2e3f139e DW |
178 | static inline void devm_memunmap_pages(struct device *dev, |
179 | struct dev_pagemap *pgmap) | |
180 | { | |
181 | } | |
182 | ||
0822acb8 CH |
183 | static inline struct dev_pagemap *get_dev_pagemap(unsigned long pfn, |
184 | struct dev_pagemap *pgmap) | |
9476df7d DW |
185 | { |
186 | return NULL; | |
187 | } | |
8e37d00a | 188 | |
34dc45be DW |
189 | static inline bool pgmap_pfn_valid(struct dev_pagemap *pgmap, unsigned long pfn) |
190 | { | |
191 | return false; | |
192 | } | |
193 | ||
8e37d00a CH |
194 | static inline unsigned long vmem_altmap_offset(struct vmem_altmap *altmap) |
195 | { | |
196 | return 0; | |
197 | } | |
198 | ||
199 | static inline void vmem_altmap_free(struct vmem_altmap *altmap, | |
200 | unsigned long nr_pfns) | |
201 | { | |
202 | } | |
9ffc1d19 DW |
203 | |
204 | /* when memremap_pages() is disabled all archs can remap a single page */ | |
205 | static inline unsigned long memremap_compat_align(void) | |
206 | { | |
207 | return PAGE_SIZE; | |
208 | } | |
8e37d00a | 209 | #endif /* CONFIG_ZONE_DEVICE */ |
7b2d55d2 | 210 | |
5c2c2587 DW |
211 | static inline void put_dev_pagemap(struct dev_pagemap *pgmap) |
212 | { | |
213 | if (pgmap) | |
b80892ca | 214 | percpu_ref_put(&pgmap->ref); |
5c2c2587 | 215 | } |
9ffc1d19 | 216 | |
9476df7d | 217 | #endif /* _LINUX_MEMREMAP_H_ */ |