include/linux/highmem.h

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