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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
9476df7d DW |
2 | #ifndef _LINUX_MEMREMAP_H_ |
3 | #define _LINUX_MEMREMAP_H_ | |
a4574f63 | 4 | #include <linux/range.h> |
5c2c2587 DW |
5 | #include <linux/ioport.h> |
6 | #include <linux/percpu-refcount.h> | |
9476df7d DW |
7 | |
8 | struct resource; | |
9 | struct device; | |
4b94ffdc DW |
10 | |
11 | /** | |
12 | * struct vmem_altmap - pre-allocated storage for vmemmap_populate | |
13 | * @base_pfn: base of the entire dev_pagemap mapping | |
14 | * @reserve: pages mapped, but reserved for driver use (relative to @base) | |
15 | * @free: free pages set aside in the mapping for memmap storage | |
16 | * @align: pages reserved to meet allocation alignments | |
17 | * @alloc: track pages consumed, private to vmemmap_populate() | |
18 | */ | |
19 | struct vmem_altmap { | |
a08a2ae3 | 20 | unsigned long base_pfn; |
cf387d96 | 21 | const unsigned long end_pfn; |
4b94ffdc DW |
22 | const unsigned long reserve; |
23 | unsigned long free; | |
24 | unsigned long align; | |
25 | unsigned long alloc; | |
26 | }; | |
27 | ||
5042db43 | 28 | /* |
041711ce | 29 | * Specialize ZONE_DEVICE memory into multiple types each has a different |
5042db43 JG |
30 | * usage. |
31 | * | |
5042db43 JG |
32 | * MEMORY_DEVICE_PRIVATE: |
33 | * Device memory that is not directly addressable by the CPU: CPU can neither | |
34 | * read nor write private memory. In this case, we do still have struct pages | |
35 | * backing the device memory. Doing so simplifies the implementation, but it is | |
36 | * important to remember that there are certain points at which the struct page | |
37 | * must be treated as an opaque object, rather than a "normal" struct page. | |
38 | * | |
39 | * A more complete discussion of unaddressable memory may be found in | |
ad56b738 | 40 | * include/linux/hmm.h and Documentation/vm/hmm.rst. |
df6ad698 | 41 | * |
e7638488 DW |
42 | * MEMORY_DEVICE_FS_DAX: |
43 | * Host memory that has similar access semantics as System RAM i.e. DMA | |
44 | * coherent and supports page pinning. In support of coordinating page | |
45 | * pinning vs other operations MEMORY_DEVICE_FS_DAX arranges for a | |
46 | * wakeup event whenever a page is unpinned and becomes idle. This | |
47 | * wakeup is used to coordinate physical address space management (ex: | |
48 | * fs truncate/hole punch) vs pinned pages (ex: device dma). | |
52916982 | 49 | * |
4533d3ae | 50 | * MEMORY_DEVICE_GENERIC: |
3ed2dcdf | 51 | * Host memory that has similar access semantics as System RAM i.e. DMA |
4533d3ae RPM |
52 | * coherent and supports page pinning. This is for example used by DAX devices |
53 | * that expose memory using a character device. | |
3ed2dcdf | 54 | * |
52916982 LG |
55 | * MEMORY_DEVICE_PCI_P2PDMA: |
56 | * Device memory residing in a PCI BAR intended for use with Peer-to-Peer | |
57 | * transactions. | |
5042db43 JG |
58 | */ |
59 | enum memory_type { | |
3ed2dcdf | 60 | /* 0 is reserved to catch uninitialized type fields */ |
e7638488 | 61 | MEMORY_DEVICE_PRIVATE = 1, |
e7638488 | 62 | MEMORY_DEVICE_FS_DAX, |
4533d3ae | 63 | MEMORY_DEVICE_GENERIC, |
52916982 | 64 | MEMORY_DEVICE_PCI_P2PDMA, |
5042db43 JG |
65 | }; |
66 | ||
1e240e8d CH |
67 | struct dev_pagemap_ops { |
68 | /* | |
69 | * Called once the page refcount reaches 1. (ZONE_DEVICE pages never | |
70 | * reach 0 refcount unless there is a refcount bug. This allows the | |
71 | * device driver to implement its own memory management.) | |
72 | */ | |
80a72d0a | 73 | void (*page_free)(struct page *page); |
1e240e8d | 74 | |
897e6365 CH |
75 | /* |
76 | * Used for private (un-addressable) device memory only. Must migrate | |
77 | * the page back to a CPU accessible page. | |
78 | */ | |
79 | vm_fault_t (*migrate_to_ram)(struct vm_fault *vmf); | |
1e240e8d | 80 | }; |
5042db43 | 81 | |
514caf23 CH |
82 | #define PGMAP_ALTMAP_VALID (1 << 0) |
83 | ||
9476df7d DW |
84 | /** |
85 | * struct dev_pagemap - metadata for ZONE_DEVICE mappings | |
4b94ffdc | 86 | * @altmap: pre-allocated/reserved memory for vmemmap allocations |
5c2c2587 | 87 | * @ref: reference count that pins the devm_memremap_pages() mapping |
b80892ca | 88 | * @done: completion for @ref |
5042db43 | 89 | * @type: memory type: see MEMORY_* in memory_hotplug.h |
514caf23 | 90 | * @flags: PGMAP_* flags to specify defailed behavior |
c4386bd8 JM |
91 | * @vmemmap_shift: structural definition of how the vmemmap page metadata |
92 | * is populated, specifically the metadata page order. | |
93 | * A zero value (default) uses base pages as the vmemmap metadata | |
94 | * representation. A bigger value will set up compound struct pages | |
95 | * of the requested order value. | |
1e240e8d | 96 | * @ops: method table |
f894ddd5 CH |
97 | * @owner: an opaque pointer identifying the entity that manages this |
98 | * instance. Used by various helpers to make sure that no | |
99 | * foreign ZONE_DEVICE memory is accessed. | |
b7b3c01b DW |
100 | * @nr_range: number of ranges to be mapped |
101 | * @range: range to be mapped when nr_range == 1 | |
102 | * @ranges: array of ranges to be mapped when nr_range > 1 | |
9476df7d DW |
103 | */ |
104 | struct dev_pagemap { | |
e7744aa2 | 105 | struct vmem_altmap altmap; |
b80892ca | 106 | struct percpu_ref ref; |
24917f6b | 107 | struct completion done; |
5042db43 | 108 | enum memory_type type; |
514caf23 | 109 | unsigned int flags; |
c4386bd8 | 110 | unsigned long vmemmap_shift; |
1e240e8d | 111 | const struct dev_pagemap_ops *ops; |
f894ddd5 | 112 | void *owner; |
b7b3c01b DW |
113 | int nr_range; |
114 | union { | |
115 | struct range range; | |
116 | struct range ranges[0]; | |
117 | }; | |
9476df7d DW |
118 | }; |
119 | ||
514caf23 CH |
120 | static inline struct vmem_altmap *pgmap_altmap(struct dev_pagemap *pgmap) |
121 | { | |
122 | if (pgmap->flags & PGMAP_ALTMAP_VALID) | |
123 | return &pgmap->altmap; | |
124 | return NULL; | |
125 | } | |
126 | ||
c4386bd8 JM |
127 | static inline unsigned long pgmap_vmemmap_nr(struct dev_pagemap *pgmap) |
128 | { | |
129 | return 1 << pgmap->vmemmap_shift; | |
130 | } | |
131 | ||
9476df7d | 132 | #ifdef CONFIG_ZONE_DEVICE |
6869b7b2 CH |
133 | void *memremap_pages(struct dev_pagemap *pgmap, int nid); |
134 | void memunmap_pages(struct dev_pagemap *pgmap); | |
e8d51348 | 135 | void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap); |
2e3f139e | 136 | void devm_memunmap_pages(struct device *dev, struct dev_pagemap *pgmap); |
0822acb8 CH |
137 | struct dev_pagemap *get_dev_pagemap(unsigned long pfn, |
138 | struct dev_pagemap *pgmap); | |
34dc45be | 139 | bool pgmap_pfn_valid(struct dev_pagemap *pgmap, unsigned long pfn); |
7b2d55d2 | 140 | |
8e37d00a CH |
141 | unsigned long vmem_altmap_offset(struct vmem_altmap *altmap); |
142 | void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns); | |
9ffc1d19 | 143 | unsigned long memremap_compat_align(void); |
9476df7d DW |
144 | #else |
145 | static inline void *devm_memremap_pages(struct device *dev, | |
e8d51348 | 146 | struct dev_pagemap *pgmap) |
9476df7d DW |
147 | { |
148 | /* | |
149 | * Fail attempts to call devm_memremap_pages() without | |
150 | * ZONE_DEVICE support enabled, this requires callers to fall | |
151 | * back to plain devm_memremap() based on config | |
152 | */ | |
153 | WARN_ON_ONCE(1); | |
154 | return ERR_PTR(-ENXIO); | |
155 | } | |
156 | ||
2e3f139e DW |
157 | static inline void devm_memunmap_pages(struct device *dev, |
158 | struct dev_pagemap *pgmap) | |
159 | { | |
160 | } | |
161 | ||
0822acb8 CH |
162 | static inline struct dev_pagemap *get_dev_pagemap(unsigned long pfn, |
163 | struct dev_pagemap *pgmap) | |
9476df7d DW |
164 | { |
165 | return NULL; | |
166 | } | |
8e37d00a | 167 | |
34dc45be DW |
168 | static inline bool pgmap_pfn_valid(struct dev_pagemap *pgmap, unsigned long pfn) |
169 | { | |
170 | return false; | |
171 | } | |
172 | ||
8e37d00a CH |
173 | static inline unsigned long vmem_altmap_offset(struct vmem_altmap *altmap) |
174 | { | |
175 | return 0; | |
176 | } | |
177 | ||
178 | static inline void vmem_altmap_free(struct vmem_altmap *altmap, | |
179 | unsigned long nr_pfns) | |
180 | { | |
181 | } | |
9ffc1d19 DW |
182 | |
183 | /* when memremap_pages() is disabled all archs can remap a single page */ | |
184 | static inline unsigned long memremap_compat_align(void) | |
185 | { | |
186 | return PAGE_SIZE; | |
187 | } | |
8e37d00a | 188 | #endif /* CONFIG_ZONE_DEVICE */ |
7b2d55d2 | 189 | |
5c2c2587 DW |
190 | static inline void put_dev_pagemap(struct dev_pagemap *pgmap) |
191 | { | |
192 | if (pgmap) | |
b80892ca | 193 | percpu_ref_put(&pgmap->ref); |
5c2c2587 | 194 | } |
9ffc1d19 | 195 | |
9476df7d | 196 | #endif /* _LINUX_MEMREMAP_H_ */ |