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
   7 #include <asm/cacheflush.h>
   8
   9 #ifndef ARCH_HAS_FLUSH_ANON_PAGE
  10 static inline void flush_anon_page(struct page *page, unsigned long vmaddr)
  11 {
  12 }
  13 #endif
  14
  15 #ifndef ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE
  16 static inline void flush_kernel_dcache_page(struct page *page)
  17 {
  18 }
  19 #endif
  20
  21 #ifdef CONFIG_HIGHMEM
  22
  23 #include <asm/highmem.h>
  24
  25 /* declarations for linux/mm/highmem.c */
  26 unsigned int nr_free_highpages(void);
  27 extern unsigned long totalhigh_pages;
  28
  29 #else /* CONFIG_HIGHMEM */
  30
  31 static inline unsigned int nr_free_highpages(void) { return 0; }
  32
  33 #define totalhigh_pages 0
  34
  35 #ifndef ARCH_HAS_KMAP
  36 static inline void *kmap(struct page *page)
  37 {
  38         might_sleep();
  39         return page_address(page);
  40 }
  41
  42 #define kunmap(page) do { (void) (page); } while (0)
  43
  44 #define kmap_atomic(page, idx)          page_address(page)
  45 #define kunmap_atomic(addr, idx)        do { } while (0)
  46 #define kmap_atomic_pfn(pfn, idx)       page_address(pfn_to_page(pfn))
  47 #define kmap_atomic_to_page(ptr)        virt_to_page(ptr)
  48 #endif
  49
  50 #endif /* CONFIG_HIGHMEM */
  51
  52 /* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */
  53 static inline void clear_user_highpage(struct page *page, unsigned long vaddr)
  54 {
  55         void *addr = kmap_atomic(page, KM_USER0);
  56         clear_user_page(addr, vaddr, page);
  57         kunmap_atomic(addr, KM_USER0);
  58         /* Make sure this page is cleared on other CPU's too before using it */
  59         smp_wmb();
  60 }
  61
  62 #ifndef __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE
  63 static inline struct page *
  64 alloc_zeroed_user_highpage(struct vm_area_struct *vma, unsigned long vaddr)
  65 {
  66         struct page *page = alloc_page_vma(GFP_HIGHUSER, vma, vaddr);
  67
  68         if (page)
  69                 clear_user_highpage(page, vaddr);
  70
  71         return page;
  72 }
  73 #endif
  74
  75 static inline void clear_highpage(struct page *page)
  76 {
  77         void *kaddr = kmap_atomic(page, KM_USER0);
  78         clear_page(kaddr);
  79         kunmap_atomic(kaddr, KM_USER0);
  80 }
  81
  82 /*
  83  * Same but also flushes aliased cache contents to RAM.
  84  */
  85 static inline void memclear_highpage_flush(struct page *page, unsigned int offset, unsigned int size)
  86 {
  87         void *kaddr;
  88
  89         BUG_ON(offset + size > PAGE_SIZE);
  90
  91         kaddr = kmap_atomic(page, KM_USER0);
  92         memset((char *)kaddr + offset, 0, size);
  93         flush_dcache_page(page);
  94         kunmap_atomic(kaddr, KM_USER0);
  95 }
  96
  97 static inline void copy_user_highpage(struct page *to, struct page *from, unsigned long vaddr)
  98 {
  99         char *vfrom, *vto;
 100
 101         vfrom = kmap_atomic(from, KM_USER0);
 102         vto = kmap_atomic(to, KM_USER1);
 103         copy_user_page(vto, vfrom, vaddr, to);
 104         kunmap_atomic(vfrom, KM_USER0);
 105         kunmap_atomic(vto, KM_USER1);
 106         /* Make sure this page is cleared on other CPU's too before using it */
 107         smp_wmb();
 108 }
 109
 110 static inline void copy_highpage(struct page *to, struct page *from)
 111 {
 112         char *vfrom, *vto;
 113
 114         vfrom = kmap_atomic(from, KM_USER0);
 115         vto = kmap_atomic(to, KM_USER1);
 116         copy_page(vto, vfrom);
 117         kunmap_atomic(vfrom, KM_USER0);
 118         kunmap_atomic(vto, KM_USER1);
 119 }
 120
 121 #endif /* _LINUX_HIGHMEM_H */