1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_HIGHMEM_H
3 #define _LINUX_HIGHMEM_H
4
5 #include <linux/fs.h>
6 #include <linux/kernel.h>
7 #include <linux/bug.h>
8 #include <linux/mm.h>
9 #include <linux/uaccess.h>
10 #include <linux/hardirq.h>
11
12 #include <asm/cacheflush.h>
13
14 #ifndef ARCH_HAS_FLUSH_ANON_PAGE
flush_anon_page(struct vm_area_struct * vma,struct page * page,unsigned long vmaddr)15 static inline void flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned long vmaddr)
16 {
17 }
18 #endif
19
20 #ifndef ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE
flush_kernel_dcache_page(struct page * page)21 static inline void flush_kernel_dcache_page(struct page *page)
22 {
23 }
flush_kernel_vmap_range(void * vaddr,int size)24 static inline void flush_kernel_vmap_range(void *vaddr, int size)
25 {
26 }
invalidate_kernel_vmap_range(void * vaddr,int size)27 static inline void invalidate_kernel_vmap_range(void *vaddr, int size)
28 {
29 }
30 #endif
31
32 #include <asm/kmap_types.h>
33
34 #ifdef CONFIG_HIGHMEM
35 #include <asm/highmem.h>
36
37 /* declarations for linux/mm/highmem.c */
38 unsigned int nr_free_highpages(void);
39 extern atomic_long_t _totalhigh_pages;
totalhigh_pages(void)40 static inline unsigned long totalhigh_pages(void)
41 {
42 return (unsigned long)atomic_long_read(&_totalhigh_pages);
43 }
44
totalhigh_pages_inc(void)45 static inline void totalhigh_pages_inc(void)
46 {
47 atomic_long_inc(&_totalhigh_pages);
48 }
49
totalhigh_pages_dec(void)50 static inline void totalhigh_pages_dec(void)
51 {
52 atomic_long_dec(&_totalhigh_pages);
53 }
54
totalhigh_pages_add(long count)55 static inline void totalhigh_pages_add(long count)
56 {
57 atomic_long_add(count, &_totalhigh_pages);
58 }
59
totalhigh_pages_set(long val)60 static inline void totalhigh_pages_set(long val)
61 {
62 atomic_long_set(&_totalhigh_pages, val);
63 }
64
65 void kmap_flush_unused(void);
66
67 struct page *kmap_to_page(void *addr);
68
69 #else /* CONFIG_HIGHMEM */
70
nr_free_highpages(void)71 static inline unsigned int nr_free_highpages(void) { return 0; }
72
kmap_to_page(void * addr)73 static inline struct page *kmap_to_page(void *addr)
74 {
75 return virt_to_page(addr);
76 }
77
totalhigh_pages(void)78 static inline unsigned long totalhigh_pages(void) { return 0UL; }
79
80 #ifndef ARCH_HAS_KMAP
kmap(struct page * page)81 static inline void *kmap(struct page *page)
82 {
83 might_sleep();
84 return page_address(page);
85 }
86
kunmap(struct page * page)87 static inline void kunmap(struct page *page)
88 {
89 }
90
kmap_atomic(struct page * page)91 static inline void *kmap_atomic(struct page *page)
92 {
93 preempt_disable();
94 pagefault_disable();
95 return page_address(page);
96 }
97 #define kmap_atomic_prot(page, prot) kmap_atomic(page)
98
__kunmap_atomic(void * addr)99 static inline void __kunmap_atomic(void *addr)
100 {
101 pagefault_enable();
102 preempt_enable();
103 }
104
105 #define kmap_atomic_pfn(pfn) kmap_atomic(pfn_to_page(pfn))
106
107 #define kmap_flush_unused() do {} while(0)
108 #endif
109
110 #endif /* CONFIG_HIGHMEM */
111
112 #if defined(CONFIG_HIGHMEM) || defined(CONFIG_X86_32)
113
114 DECLARE_PER_CPU(int, __kmap_atomic_idx);
115
kmap_atomic_idx_push(void)116 static inline int kmap_atomic_idx_push(void)
117 {
118 int idx = __this_cpu_inc_return(__kmap_atomic_idx) - 1;
119
120 #ifdef CONFIG_DEBUG_HIGHMEM
121 WARN_ON_ONCE(in_irq() && !irqs_disabled());
122 BUG_ON(idx >= KM_TYPE_NR);
123 #endif
124 return idx;
125 }
126
kmap_atomic_idx(void)127 static inline int kmap_atomic_idx(void)
128 {
129 return __this_cpu_read(__kmap_atomic_idx) - 1;
130 }
131
kmap_atomic_idx_pop(void)132 static inline void kmap_atomic_idx_pop(void)
133 {
134 #ifdef CONFIG_DEBUG_HIGHMEM
135 int idx = __this_cpu_dec_return(__kmap_atomic_idx);
136
137 BUG_ON(idx < 0);
138 #else
139 __this_cpu_dec(__kmap_atomic_idx);
140 #endif
141 }
142
143 #endif
144
145 /*
146 * Prevent people trying to call kunmap_atomic() as if it were kunmap()
147 * kunmap_atomic() should get the return value of kmap_atomic, not the page.
148 */
149 #define kunmap_atomic(addr) \
150 do { \
151 BUILD_BUG_ON(__same_type((addr), struct page *)); \
152 __kunmap_atomic(addr); \
153 } while (0)
154
155
156 /* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */
157 #ifndef clear_user_highpage
clear_user_highpage(struct page * page,unsigned long vaddr)158 static inline void clear_user_highpage(struct page *page, unsigned long vaddr)
159 {
160 void *addr = kmap_atomic(page);
161 clear_user_page(addr, vaddr, page);
162 kunmap_atomic(addr);
163 }
164 #endif
165
166 #ifndef __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE
167 /**
168 * __alloc_zeroed_user_highpage - Allocate a zeroed HIGHMEM page for a VMA with caller-specified movable GFP flags
169 * @movableflags: The GFP flags related to the pages future ability to move like __GFP_MOVABLE
170 * @vma: The VMA the page is to be allocated for
171 * @vaddr: The virtual address the page will be inserted into
172 *
173 * This function will allocate a page for a VMA but the caller is expected
174 * to specify via movableflags whether the page will be movable in the
175 * future or not
176 *
177 * An architecture may override this function by defining
178 * __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE and providing their own
179 * implementation.
180 */
181 static inline struct page *
__alloc_zeroed_user_highpage(gfp_t movableflags,struct vm_area_struct * vma,unsigned long vaddr)182 __alloc_zeroed_user_highpage(gfp_t movableflags,
183 struct vm_area_struct *vma,
184 unsigned long vaddr)
185 {
186 struct page *page = alloc_page_vma(GFP_HIGHUSER | movableflags,
187 vma, vaddr);
188
189 if (page)
190 clear_user_highpage(page, vaddr);
191
192 return page;
193 }
194 #endif
195
196 /**
197 * alloc_zeroed_user_highpage_movable - Allocate a zeroed HIGHMEM page for a VMA that the caller knows can move
198 * @vma: The VMA the page is to be allocated for
199 * @vaddr: The virtual address the page will be inserted into
200 *
201 * This function will allocate a page for a VMA that the caller knows will
202 * be able to migrate in the future using move_pages() or reclaimed
203 */
204 static inline struct page *
alloc_zeroed_user_highpage_movable(struct vm_area_struct * vma,unsigned long vaddr)205 alloc_zeroed_user_highpage_movable(struct vm_area_struct *vma,
206 unsigned long vaddr)
207 {
208 #ifndef CONFIG_CMA
209 return __alloc_zeroed_user_highpage(__GFP_MOVABLE, vma, vaddr);
210 #else
211 return __alloc_zeroed_user_highpage(__GFP_MOVABLE|__GFP_CMA, vma,
212 vaddr);
213 #endif
214 }
215
clear_highpage(struct page * page)216 static inline void clear_highpage(struct page *page)
217 {
218 void *kaddr = kmap_atomic(page);
219 clear_page(kaddr);
220 kunmap_atomic(kaddr);
221 }
222
zero_user_segments(struct page * page,unsigned start1,unsigned end1,unsigned start2,unsigned end2)223 static inline void zero_user_segments(struct page *page,
224 unsigned start1, unsigned end1,
225 unsigned start2, unsigned end2)
226 {
227 void *kaddr = kmap_atomic(page);
228
229 BUG_ON(end1 > PAGE_SIZE || end2 > PAGE_SIZE);
230
231 if (end1 > start1)
232 memset(kaddr + start1, 0, end1 - start1);
233
234 if (end2 > start2)
235 memset(kaddr + start2, 0, end2 - start2);
236
237 kunmap_atomic(kaddr);
238 flush_dcache_page(page);
239 }
240
zero_user_segment(struct page * page,unsigned start,unsigned end)241 static inline void zero_user_segment(struct page *page,
242 unsigned start, unsigned end)
243 {
244 zero_user_segments(page, start, end, 0, 0);
245 }
246
zero_user(struct page * page,unsigned start,unsigned size)247 static inline void zero_user(struct page *page,
248 unsigned start, unsigned size)
249 {
250 zero_user_segments(page, start, start + size, 0, 0);
251 }
252
253 #ifndef __HAVE_ARCH_COPY_USER_HIGHPAGE
254
copy_user_highpage(struct page * to,struct page * from,unsigned long vaddr,struct vm_area_struct * vma)255 static inline void copy_user_highpage(struct page *to, struct page *from,
256 unsigned long vaddr, struct vm_area_struct *vma)
257 {
258 char *vfrom, *vto;
259
260 vfrom = kmap_atomic(from);
261 vto = kmap_atomic(to);
262 copy_user_page(vto, vfrom, vaddr, to);
263 kunmap_atomic(vto);
264 kunmap_atomic(vfrom);
265 }
266
267 #endif
268
269 #ifndef __HAVE_ARCH_COPY_HIGHPAGE
270
copy_highpage(struct page * to,struct page * from)271 static inline void copy_highpage(struct page *to, struct page *from)
272 {
273 char *vfrom, *vto;
274
275 vfrom = kmap_atomic(from);
276 vto = kmap_atomic(to);
277 copy_page(vto, vfrom);
278 kunmap_atomic(vto);
279 kunmap_atomic(vfrom);
280 }
281
282 #endif
283
memcpy_from_page(char * to,struct page * page,size_t offset,size_t len)284 static inline void memcpy_from_page(char *to, struct page *page,
285 size_t offset, size_t len)
286 {
287 char *from = kmap_atomic(page);
288
289 memcpy(to, from + offset, len);
290 kunmap_atomic(from);
291 }
292
memcpy_to_page(struct page * page,size_t offset,const char * from,size_t len)293 static inline void memcpy_to_page(struct page *page, size_t offset,
294 const char *from, size_t len)
295 {
296 char *to = kmap_atomic(page);
297
298 memcpy(to + offset, from, len);
299 kunmap_atomic(to);
300 }
301
302 #endif /* _LINUX_HIGHMEM_H */
303