include/linux/highmem.h

   1 #ifndef _LINUX_HIGHMEM_H
   2 #define _LINUX_HIGHMEM_H
   3
   4 #include <linux/config.h>
   5 #include <linux/fs.h>
   6 #include <linux/mm.h>
   7
   8 #include <asm/cacheflush.h>
   9
  10 #ifdef CONFIG_HIGHMEM
  11
  12 #include <asm/highmem.h>
  13
  14 /* declarations for linux/mm/highmem.c */
  15 unsigned int nr_free_highpages(void);
  16
  17 #else /* CONFIG_HIGHMEM */
  18
  19 static inline unsigned int nr_free_highpages(void) { return 0; }
  20
  21 static inline void *kmap(struct page *page)
  22 {
  23         might_sleep();
  24         return page_address(page);
  25 }
  26
  27 #define kunmap(page) do { (void) (page); } while (0)
  28
  29 #define kmap_atomic(page, idx)          page_address(page)
  30 #define kunmap_atomic(addr, idx)        do { } while (0)
  31 #define kmap_atomic_pfn(pfn, idx)       page_address(pfn_to_page(pfn))
  32 #define kmap_atomic_to_page(ptr)        virt_to_page(ptr)
  33
  34 #endif /* CONFIG_HIGHMEM */
  35
  36 /* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */
  37 static inline void clear_user_highpage(struct page *page, unsigned long vaddr)
  38 {
  39         void *addr = kmap_atomic(page, KM_USER0);
  40         clear_user_page(addr, vaddr, page);
  41         kunmap_atomic(addr, KM_USER0);
  42         /* Make sure this page is cleared on other CPU's too before using it */
  43         smp_wmb();
  44 }
  45
  46 #ifndef __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE
  47 static inline struct page *
  48 alloc_zeroed_user_highpage(struct vm_area_struct *vma, unsigned long vaddr)
  49 {
  50         struct page *page = alloc_page_vma(GFP_HIGHUSER, vma, vaddr);
  51
  52         if (page)
  53                 clear_user_highpage(page, vaddr);
  54
  55         return page;
  56 }
  57 #endif
  58
  59 static inline void clear_highpage(struct page *page)
  60 {
  61         void *kaddr = kmap_atomic(page, KM_USER0);
  62         clear_page(kaddr);
  63         kunmap_atomic(kaddr, KM_USER0);
  64 }
  65
  66 /*
  67  * Same but also flushes aliased cache contents to RAM.
  68  */
  69 static inline void memclear_highpage_flush(struct page *page, unsigned int offset, unsigned int size)
  70 {
  71         void *kaddr;
  72
  73         BUG_ON(offset + size > PAGE_SIZE);
  74
  75         kaddr = kmap_atomic(page, KM_USER0);
  76         memset((char *)kaddr + offset, 0, size);
  77         flush_dcache_page(page);
  78         kunmap_atomic(kaddr, KM_USER0);
  79 }
  80
  81 static inline void copy_user_highpage(struct page *to, struct page *from, unsigned long vaddr)
  82 {
  83         char *vfrom, *vto;
  84
  85         vfrom = kmap_atomic(from, KM_USER0);
  86         vto = kmap_atomic(to, KM_USER1);
  87         copy_user_page(vto, vfrom, vaddr, to);
  88         kunmap_atomic(vfrom, KM_USER0);
  89         kunmap_atomic(vto, KM_USER1);
  90         /* Make sure this page is cleared on other CPU's too before using it */
  91         smp_wmb();
  92 }
  93
  94 static inline void copy_highpage(struct page *to, struct page *from)
  95 {
  96         char *vfrom, *vto;
  97
  98         vfrom = kmap_atomic(from, KM_USER0);
  99         vto = kmap_atomic(to, KM_USER1);
 100         copy_page(vto, vfrom);
 101         kunmap_atomic(vfrom, KM_USER0);
 102         kunmap_atomic(vto, KM_USER1);
 103 }
 104
 105 #endif /* _LINUX_HIGHMEM_H */