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TOMOYO Linux Cross Reference
Linux/include/linux/highmem.h

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  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
 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
 21 static inline void flush_kernel_dcache_page(struct page *page)
 22 {
 23 }
 24 static inline void flush_kernel_vmap_range(void *vaddr, int size)
 25 {
 26 }
 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 unsigned long totalhigh_pages;
 40 
 41 void kmap_flush_unused(void);
 42 
 43 struct page *kmap_to_page(void *addr);
 44 
 45 #else /* CONFIG_HIGHMEM */
 46 
 47 static inline unsigned int nr_free_highpages(void) { return 0; }
 48 
 49 static inline struct page *kmap_to_page(void *addr)
 50 {
 51         return virt_to_page(addr);
 52 }
 53 
 54 #define totalhigh_pages 0UL
 55 
 56 #ifndef ARCH_HAS_KMAP
 57 static inline void *kmap(struct page *page)
 58 {
 59         might_sleep();
 60         return page_address(page);
 61 }
 62 
 63 static inline void kunmap(struct page *page)
 64 {
 65 }
 66 
 67 static inline void *kmap_atomic(struct page *page)
 68 {
 69         preempt_disable();
 70         pagefault_disable();
 71         return page_address(page);
 72 }
 73 #define kmap_atomic_prot(page, prot)    kmap_atomic(page)
 74 
 75 static inline void __kunmap_atomic(void *addr)
 76 {
 77         pagefault_enable();
 78         preempt_enable();
 79 }
 80 
 81 #define kmap_atomic_pfn(pfn)    kmap_atomic(pfn_to_page(pfn))
 82 
 83 #define kmap_flush_unused()     do {} while(0)
 84 #endif
 85 
 86 #endif /* CONFIG_HIGHMEM */
 87 
 88 #if defined(CONFIG_HIGHMEM) || defined(CONFIG_X86_32)
 89 
 90 DECLARE_PER_CPU(int, __kmap_atomic_idx);
 91 
 92 static inline int kmap_atomic_idx_push(void)
 93 {
 94         int idx = __this_cpu_inc_return(__kmap_atomic_idx) - 1;
 95 
 96 #ifdef CONFIG_DEBUG_HIGHMEM
 97         WARN_ON_ONCE(in_irq() && !irqs_disabled());
 98         BUG_ON(idx >= KM_TYPE_NR);
 99 #endif
100         return idx;
101 }
102 
103 static inline int kmap_atomic_idx(void)
104 {
105         return __this_cpu_read(__kmap_atomic_idx) - 1;
106 }
107 
108 static inline void kmap_atomic_idx_pop(void)
109 {
110 #ifdef CONFIG_DEBUG_HIGHMEM
111         int idx = __this_cpu_dec_return(__kmap_atomic_idx);
112 
113         BUG_ON(idx < 0);
114 #else
115         __this_cpu_dec(__kmap_atomic_idx);
116 #endif
117 }
118 
119 #endif
120 
121 /*
122  * Prevent people trying to call kunmap_atomic() as if it were kunmap()
123  * kunmap_atomic() should get the return value of kmap_atomic, not the page.
124  */
125 #define kunmap_atomic(addr)                                     \
126 do {                                                            \
127         BUILD_BUG_ON(__same_type((addr), struct page *));       \
128         __kunmap_atomic(addr);                                  \
129 } while (0)
130 
131 
132 /* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */
133 #ifndef clear_user_highpage
134 static inline void clear_user_highpage(struct page *page, unsigned long vaddr)
135 {
136         void *addr = kmap_atomic(page);
137         clear_user_page(addr, vaddr, page);
138         kunmap_atomic(addr);
139 }
140 #endif
141 
142 #ifndef __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE
143 /**
144  * __alloc_zeroed_user_highpage - Allocate a zeroed HIGHMEM page for a VMA with caller-specified movable GFP flags
145  * @movableflags: The GFP flags related to the pages future ability to move like __GFP_MOVABLE
146  * @vma: The VMA the page is to be allocated for
147  * @vaddr: The virtual address the page will be inserted into
148  *
149  * This function will allocate a page for a VMA but the caller is expected
150  * to specify via movableflags whether the page will be movable in the
151  * future or not
152  *
153  * An architecture may override this function by defining
154  * __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE and providing their own
155  * implementation.
156  */
157 static inline struct page *
158 __alloc_zeroed_user_highpage(gfp_t movableflags,
159                         struct vm_area_struct *vma,
160                         unsigned long vaddr)
161 {
162         struct page *page = alloc_page_vma(GFP_HIGHUSER | movableflags,
163                         vma, vaddr);
164 
165         if (page)
166                 clear_user_highpage(page, vaddr);
167 
168         return page;
169 }
170 #endif
171 
172 /**
173  * alloc_zeroed_user_highpage_movable - Allocate a zeroed HIGHMEM page for a VMA that the caller knows can move
174  * @vma: The VMA the page is to be allocated for
175  * @vaddr: The virtual address the page will be inserted into
176  *
177  * This function will allocate a page for a VMA that the caller knows will
178  * be able to migrate in the future using move_pages() or reclaimed
179  */
180 static inline struct page *
181 alloc_zeroed_user_highpage_movable(struct vm_area_struct *vma,
182                                         unsigned long vaddr)
183 {
184         return __alloc_zeroed_user_highpage(__GFP_MOVABLE, vma, vaddr);
185 }
186 
187 static inline void clear_highpage(struct page *page)
188 {
189         void *kaddr = kmap_atomic(page);
190         clear_page(kaddr);
191         kunmap_atomic(kaddr);
192 }
193 
194 static inline void zero_user_segments(struct page *page,
195         unsigned start1, unsigned end1,
196         unsigned start2, unsigned end2)
197 {
198         void *kaddr = kmap_atomic(page);
199 
200         BUG_ON(end1 > PAGE_SIZE || end2 > PAGE_SIZE);
201 
202         if (end1 > start1)
203                 memset(kaddr + start1, 0, end1 - start1);
204 
205         if (end2 > start2)
206                 memset(kaddr + start2, 0, end2 - start2);
207 
208         kunmap_atomic(kaddr);
209         flush_dcache_page(page);
210 }
211 
212 static inline void zero_user_segment(struct page *page,
213         unsigned start, unsigned end)
214 {
215         zero_user_segments(page, start, end, 0, 0);
216 }
217 
218 static inline void zero_user(struct page *page,
219         unsigned start, unsigned size)
220 {
221         zero_user_segments(page, start, start + size, 0, 0);
222 }
223 
224 #ifndef __HAVE_ARCH_COPY_USER_HIGHPAGE
225 
226 static inline void copy_user_highpage(struct page *to, struct page *from,
227         unsigned long vaddr, struct vm_area_struct *vma)
228 {
229         char *vfrom, *vto;
230 
231         vfrom = kmap_atomic(from);
232         vto = kmap_atomic(to);
233         copy_user_page(vto, vfrom, vaddr, to);
234         kunmap_atomic(vto);
235         kunmap_atomic(vfrom);
236 }
237 
238 #endif
239 
240 #ifndef __HAVE_ARCH_COPY_HIGHPAGE
241 
242 static inline void copy_highpage(struct page *to, struct page *from)
243 {
244         char *vfrom, *vto;
245 
246         vfrom = kmap_atomic(from);
247         vto = kmap_atomic(to);
248         copy_page(vto, vfrom);
249         kunmap_atomic(vto);
250         kunmap_atomic(vfrom);
251 }
252 
253 #endif
254 
255 #endif /* _LINUX_HIGHMEM_H */
256 

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