include/linux/highmem.h

   1 #ifndef _LINUX_HIGHMEM_H
   2 #define _LINUX_HIGHMEM_H
   3
   4 #include <linux/fs.h>
   5 #include <linux/kernel.h>
   6 #include <linux/mm.h>
   7 #include <linux/uaccess.h>
   8
   9 #include <asm/cacheflush.h>
  10
  11 #ifndef ARCH_HAS_FLUSH_ANON_PAGE
  12 static inline void flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned long vmaddr)
  13 {
  14 }
  15 #endif
  16
  17 #ifndef ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE
  18 static inline void flush_kernel_dcache_page(struct page *page)
  19 {
  20 }
  21 static inline void flush_kernel_vmap_range(void *vaddr, int size)
  22 {
  23 }
  24 static inline void invalidate_kernel_vmap_range(void *vaddr, int size)
  25 {
  26 }
  27 #endif
  28
  29 #include <asm/kmap_types.h>
  30
  31 #ifdef CONFIG_DEBUG_HIGHMEM
  32
  33 void debug_kmap_atomic(enum km_type type);
  34
  35 #else
  36
  37 static inline void debug_kmap_atomic(enum km_type type)
  38 {
  39 }
  40
  41 #endif
  42
  43 #ifdef CONFIG_HIGHMEM
  44 #include <asm/highmem.h>
  45
  46 /* declarations for linux/mm/highmem.c */
  47 unsigned int nr_free_highpages(void);
  48 extern unsigned long totalhigh_pages;
  49
  50 void kmap_flush_unused(void);
  51
  52 #else /* CONFIG_HIGHMEM */
  53
  54 static inline unsigned int nr_free_highpages(void) { return 0; }
  55
  56 #define totalhigh_pages 0UL
  57
  58 #ifndef ARCH_HAS_KMAP
  59 static inline void *kmap(struct page *page)
  60 {
  61         might_sleep();
  62         return page_address(page);
  63 }
  64
  65 static inline void kunmap(struct page *page)
  66 {
  67 }
  68
  69 static inline void *kmap_atomic(struct page *page, enum km_type idx)
  70 {
  71         pagefault_disable();
  72         return page_address(page);
  73 }
  74 #define kmap_atomic_prot(page, idx, prot)       kmap_atomic(page, idx)
  75
  76 static inline void kunmap_atomic_notypecheck(void *addr, enum km_type idx)
  77 {
  78         pagefault_enable();
  79 }
  80
  81 #define kmap_atomic_pfn(pfn, idx)       kmap_atomic(pfn_to_page(pfn), (idx))
  82 #define kmap_atomic_to_page(ptr)        virt_to_page(ptr)
  83
  84 #define kmap_flush_unused()     do {} while(0)
  85 #endif
  86
  87 #endif /* CONFIG_HIGHMEM */
  88
  89 /* Prevent people trying to call kunmap_atomic() as if it were kunmap() */
  90 /* kunmap_atomic() should get the return value of kmap_atomic, not the page. */
  91 #define kunmap_atomic(addr, idx) do { \
  92                 BUILD_BUG_ON(__same_type((addr), struct page *)); \
  93                 kunmap_atomic_notypecheck((addr), (idx)); \
  94         } while (0)
  95
  96 /* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */
  97 #ifndef clear_user_highpage
  98 static inline void clear_user_highpage(struct page *page, unsigned long vaddr)
  99 {
 100         void *addr = kmap_atomic(page, KM_USER0);
 101         clear_user_page(addr, vaddr, page);
 102         kunmap_atomic(addr, KM_USER0);
 103 }
 104 #endif
 105
 106 #ifndef __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE
 107 /**
 108  * __alloc_zeroed_user_highpage - Allocate a zeroed HIGHMEM page for a VMA with caller-specified movable GFP flags
 109  * @movableflags: The GFP flags related to the pages future ability to move like __GFP_MOVABLE
 110  * @vma: The VMA the page is to be allocated for
 111  * @vaddr: The virtual address the page will be inserted into
 112  *
 113  * This function will allocate a page for a VMA but the caller is expected
 114  * to specify via movableflags whether the page will be movable in the
 115  * future or not
 116  *
 117  * An architecture may override this function by defining
 118  * __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE and providing their own
 119  * implementation.
 120  */
 121 static inline struct page *
 122 __alloc_zeroed_user_highpage(gfp_t movableflags,
 123                         struct vm_area_struct *vma,
 124                         unsigned long vaddr)
 125 {
 126         struct page *page = alloc_page_vma(GFP_HIGHUSER | movableflags,
 127                         vma, vaddr);
 128
 129         if (page)
 130                 clear_user_highpage(page, vaddr);
 131
 132         return page;
 133 }
 134 #endif
 135
 136 /**
 137  * alloc_zeroed_user_highpage_movable - Allocate a zeroed HIGHMEM page for a VMA that the caller knows can move
 138  * @vma: The VMA the page is to be allocated for
 139  * @vaddr: The virtual address the page will be inserted into
 140  *
 141  * This function will allocate a page for a VMA that the caller knows will
 142  * be able to migrate in the future using move_pages() or reclaimed
 143  */
 144 static inline struct page *
 145 alloc_zeroed_user_highpage_movable(struct vm_area_struct *vma,
 146                                         unsigned long vaddr)
 147 {
 148         return __alloc_zeroed_user_highpage(__GFP_MOVABLE, vma, vaddr);
 149 }
 150
 151 static inline void clear_highpage(struct page *page)
 152 {
 153         void *kaddr = kmap_atomic(page, KM_USER0);
 154         clear_page(kaddr);
 155         kunmap_atomic(kaddr, KM_USER0);
 156 }
 157
 158 static inline void zero_user_segments(struct page *page,
 159         unsigned start1, unsigned end1,
 160         unsigned start2, unsigned end2)
 161 {
 162         void *kaddr = kmap_atomic(page, KM_USER0);
 163
 164         BUG_ON(end1 > PAGE_SIZE || end2 > PAGE_SIZE);
 165
 166         if (end1 > start1)
 167                 memset(kaddr + start1, 0, end1 - start1);
 168
 169         if (end2 > start2)
 170                 memset(kaddr + start2, 0, end2 - start2);
 171
 172         kunmap_atomic(kaddr, KM_USER0);
 173         flush_dcache_page(page);
 174 }
 175
 176 static inline void zero_user_segment(struct page *page,
 177         unsigned start, unsigned end)
 178 {
 179         zero_user_segments(page, start, end, 0, 0);
 180 }
 181
 182 static inline void zero_user(struct page *page,
 183         unsigned start, unsigned size)
 184 {
 185         zero_user_segments(page, start, start + size, 0, 0);
 186 }
 187
 188 static inline void __deprecated memclear_highpage_flush(struct page *page,
 189                         unsigned int offset, unsigned int size)
 190 {
 191         zero_user(page, offset, size);
 192 }
 193
 194 #ifndef __HAVE_ARCH_COPY_USER_HIGHPAGE
 195
 196 static inline void copy_user_highpage(struct page *to, struct page *from,
 197         unsigned long vaddr, struct vm_area_struct *vma)
 198 {
 199         char *vfrom, *vto;
 200
 201         vfrom = kmap_atomic(from, KM_USER0);
 202         vto = kmap_atomic(to, KM_USER1);
 203         copy_user_page(vto, vfrom, vaddr, to);
 204         kunmap_atomic(vfrom, KM_USER0);
 205         kunmap_atomic(vto, KM_USER1);
 206 }
 207
 208 #endif
 209
 210 static inline void copy_highpage(struct page *to, struct page *from)
 211 {
 212         char *vfrom, *vto;
 213
 214         vfrom = kmap_atomic(from, KM_USER0);
 215         vto = kmap_atomic(to, KM_USER1);
 216         copy_page(vto, vfrom);
 217         kunmap_atomic(vfrom, KM_USER0);
 218         kunmap_atomic(vto, KM_USER1);
 219 }
 220
 221 #endif /* _LINUX_HIGHMEM_H */