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 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 #else /* CONFIG_HIGHMEM */
  31
  32 static inline unsigned int nr_free_highpages(void) { return 0; }
  33
  34 #define totalhigh_pages 0
  35
  36 #ifndef ARCH_HAS_KMAP
  37 static inline void *kmap(struct page *page)
  38 {
  39         might_sleep();
  40         return page_address(page);
  41 }
  42
  43 #define kunmap(page) do { (void) (page); } while (0)
  44
  45 #define kmap_atomic(page, idx) \
  46         ({ pagefault_disable(); page_address(page); })
  47 #define kunmap_atomic(addr, idx)        do { pagefault_enable(); } while (0)
  48 #define kmap_atomic_pfn(pfn, idx)       kmap_atomic(pfn_to_page(pfn), (idx))
  49 #define kmap_atomic_to_page(ptr)        virt_to_page(ptr)
  50 #endif
  51
  52 #endif /* CONFIG_HIGHMEM */
  53
  54 /* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */
  55 static inline void clear_user_highpage(struct page *page, unsigned long vaddr)
  56 {
  57         void *addr = kmap_atomic(page, KM_USER0);
  58         clear_user_page(addr, vaddr, page);
  59         kunmap_atomic(addr, KM_USER0);
  60         /* Make sure this page is cleared on other CPU's too before using it */
  61         smp_wmb();
  62 }
  63
  64 #ifndef __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE
  65 static inline struct page *
  66 alloc_zeroed_user_highpage(struct vm_area_struct *vma, unsigned long vaddr)
  67 {
  68         struct page *page = alloc_page_vma(GFP_HIGHUSER, vma, vaddr);
  69
  70         if (page)
  71                 clear_user_highpage(page, vaddr);
  72
  73         return page;
  74 }
  75 #endif
  76
  77 static inline void clear_highpage(struct page *page)
  78 {
  79         void *kaddr = kmap_atomic(page, KM_USER0);
  80         clear_page(kaddr);
  81         kunmap_atomic(kaddr, KM_USER0);
  82 }
  83
  84 /*
  85  * Same but also flushes aliased cache contents to RAM.
  86  */
  87 static inline void memclear_highpage_flush(struct page *page, unsigned int offset, unsigned int size)
  88 {
  89         void *kaddr;
  90
  91         BUG_ON(offset + size > PAGE_SIZE);
  92
  93         kaddr = kmap_atomic(page, KM_USER0);
  94         memset((char *)kaddr + offset, 0, size);
  95         flush_dcache_page(page);
  96         kunmap_atomic(kaddr, KM_USER0);
  97 }
  98
  99 #ifndef __HAVE_ARCH_COPY_USER_HIGHPAGE
 100
 101 static inline void copy_user_highpage(struct page *to, struct page *from, unsigned long vaddr)
 102 {
 103         char *vfrom, *vto;
 104
 105         vfrom = kmap_atomic(from, KM_USER0);
 106         vto = kmap_atomic(to, KM_USER1);
 107         copy_user_page(vto, vfrom, vaddr, to);
 108         kunmap_atomic(vfrom, KM_USER0);
 109         kunmap_atomic(vto, KM_USER1);
 110         /* Make sure this page is cleared on other CPU's too before using it */
 111         smp_wmb();
 112 }
 113
 114 #endif
 115
 116 static inline void copy_highpage(struct page *to, struct page *from)
 117 {
 118         char *vfrom, *vto;
 119
 120         vfrom = kmap_atomic(from, KM_USER0);
 121         vto = kmap_atomic(to, KM_USER1);
 122         copy_page(vto, vfrom);
 123         kunmap_atomic(vfrom, KM_USER0);
 124         kunmap_atomic(vto, KM_USER1);
 125 }
 126
 127 #endif /* _LINUX_HIGHMEM_H */