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 #ifdef CONFIG_HIGHMEM
  23
  24 #include <asm/highmem.h>
  25
  26 /* declarations for linux/mm/highmem.c */
  27 unsigned int nr_free_highpages(void);
  28 extern unsigned long totalhigh_pages;
  29
  30 void kmap_flush_unused(void);
  31
  32 #else /* CONFIG_HIGHMEM */
  33
  34 static inline unsigned int nr_free_highpages(void) { return 0; }
  35
  36 #define totalhigh_pages 0
  37
  38 #ifndef ARCH_HAS_KMAP
  39 static inline void *kmap(struct page *page)
  40 {
  41         might_sleep();
  42         return page_address(page);
  43 }
  44
  45 #define kunmap(page) do { (void) (page); } while (0)
  46
  47 #include <asm/kmap_types.h>
  48
  49 static inline void *kmap_atomic(struct page *page, enum km_type idx)
  50 {
  51         pagefault_disable();
  52         return page_address(page);
  53 }
  54 #define kmap_atomic_prot(page, idx, prot)       kmap_atomic(page, idx)
  55
  56 #define kunmap_atomic(addr, idx)        do { pagefault_enable(); } while (0)
  57 #define kmap_atomic_pfn(pfn, idx)       kmap_atomic(pfn_to_page(pfn), (idx))
  58 #define kmap_atomic_to_page(ptr)        virt_to_page(ptr)
  59
  60 #define kmap_flush_unused()     do {} while(0)
  61 #endif
  62
  63 #endif /* CONFIG_HIGHMEM */
  64
  65 /* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */
  66 static inline void clear_user_highpage(struct page *page, unsigned long vaddr)
  67 {
  68         void *addr = kmap_atomic(page, KM_USER0);
  69         clear_user_page(addr, vaddr, page);
  70         kunmap_atomic(addr, KM_USER0);
  71         /* Make sure this page is cleared on other CPU's too before using it */
  72         smp_wmb();
  73 }
  74
  75 #ifndef __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE
  76 static inline struct page *
  77 alloc_zeroed_user_highpage(struct vm_area_struct *vma, unsigned long vaddr)
  78 {
  79         struct page *page = alloc_page_vma(GFP_HIGHUSER, vma, vaddr);
  80
  81         if (page)
  82                 clear_user_highpage(page, vaddr);
  83
  84         return page;
  85 }
  86 #endif
  87
  88 static inline void clear_highpage(struct page *page)
  89 {
  90         void *kaddr = kmap_atomic(page, KM_USER0);
  91         clear_page(kaddr);
  92         kunmap_atomic(kaddr, KM_USER0);
  93 }
  94
  95 /*
  96  * Same but also flushes aliased cache contents to RAM.
  97  *
  98  * This must be a macro because KM_USER0 and friends aren't defined if
  99  * !CONFIG_HIGHMEM
 100  */
 101 #define zero_user_page(page, offset, size, km_type)             \
 102         do {                                                    \
 103                 void *kaddr;                                    \
 104                                                                 \
 105                 BUG_ON((offset) + (size) > PAGE_SIZE);          \
 106                                                                 \
 107                 kaddr = kmap_atomic(page, km_type);             \
 108                 memset((char *)kaddr + (offset), 0, (size));    \
 109                 flush_dcache_page(page);                        \
 110                 kunmap_atomic(kaddr, (km_type));                \
 111         } while (0)
 112
 113 static inline void __deprecated memclear_highpage_flush(struct page *page,
 114                         unsigned int offset, unsigned int size)
 115 {
 116         zero_user_page(page, offset, size, KM_USER0);
 117 }
 118
 119 #ifndef __HAVE_ARCH_COPY_USER_HIGHPAGE
 120
 121 static inline void copy_user_highpage(struct page *to, struct page *from,
 122         unsigned long vaddr, struct vm_area_struct *vma)
 123 {
 124         char *vfrom, *vto;
 125
 126         vfrom = kmap_atomic(from, KM_USER0);
 127         vto = kmap_atomic(to, KM_USER1);
 128         copy_user_page(vto, vfrom, vaddr, to);
 129         kunmap_atomic(vfrom, KM_USER0);
 130         kunmap_atomic(vto, KM_USER1);
 131         /* Make sure this page is cleared on other CPU's too before using it */
 132         smp_wmb();
 133 }
 134
 135 #endif
 136
 137 static inline void copy_highpage(struct page *to, struct page *from)
 138 {
 139         char *vfrom, *vto;
 140
 141         vfrom = kmap_atomic(from, KM_USER0);
 142         vto = kmap_atomic(to, KM_USER1);
 143         copy_page(vto, vfrom);
 144         kunmap_atomic(vfrom, KM_USER0);
 145         kunmap_atomic(vto, KM_USER1);
 146 }
 147
 148 #endif /* _LINUX_HIGHMEM_H */