Home | History | Annotate | Download | only in linux 
      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 
     28 #else /* CONFIG_HIGHMEM */
     29 
     30 static inline unsigned int nr_free_highpages(void) { return 0; }
     31 
     32 static inline void *kmap(struct page *page)
     33 {
     34 	might_sleep();
     35 	return page_address(page);
     36 }
     37 
     38 #define kunmap(page) do { (void) (page); } while (0)
     39 
     40 #define kmap_atomic(page, idx)		page_address(page)
     41 #define kunmap_atomic(addr, idx)	do { } while (0)
     42 #define kmap_atomic_pfn(pfn, idx)	page_address(pfn_to_page(pfn))
     43 #define kmap_atomic_to_page(ptr)	virt_to_page(ptr)
     44 
     45 #endif /* CONFIG_HIGHMEM */
     46 
     47 /* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */
     48 static inline void clear_user_highpage(struct page *page, unsigned long vaddr)
     49 {
     50 	void *addr = kmap_atomic(page, KM_USER0);
     51 	clear_user_page(addr, vaddr, page);
     52 	kunmap_atomic(addr, KM_USER0);
     53 	/* Make sure this page is cleared on other CPU's too before using it */
     54 	smp_wmb();
     55 }
     56 
     57 #ifndef __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE
     58 static inline struct page *
     59 alloc_zeroed_user_highpage(struct vm_area_struct *vma, unsigned long vaddr)
     60 {
     61 	struct page *page = alloc_page_vma(GFP_HIGHUSER, vma, vaddr);
     62 
     63 	if (page)
     64 		clear_user_highpage(page, vaddr);
     65 
     66 	return page;
     67 }
     68 #endif
     69 
     70 static inline void clear_highpage(struct page *page)
     71 {
     72 	void *kaddr = kmap_atomic(page, KM_USER0);
     73 	clear_page(kaddr);
     74 	kunmap_atomic(kaddr, KM_USER0);
     75 }
     76 
     77 /*
     78  * Same but also flushes aliased cache contents to RAM.
     79  */
     80 static inline void memclear_highpage_flush(struct page *page, unsigned int offset, unsigned int size)
     81 {
     82 	void *kaddr;
     83 
     84 	BUG_ON(offset + size > PAGE_SIZE);
     85 
     86 	kaddr = kmap_atomic(page, KM_USER0);
     87 	memset((char *)kaddr + offset, 0, size);
     88 	flush_dcache_page(page);
     89 	kunmap_atomic(kaddr, KM_USER0);
     90 }
     91 
     92 static inline void copy_user_highpage(struct page *to, struct page *from, unsigned long vaddr)
     93 {
     94 	char *vfrom, *vto;
     95 
     96 	vfrom = kmap_atomic(from, KM_USER0);
     97 	vto = kmap_atomic(to, KM_USER1);
     98 	copy_user_page(vto, vfrom, vaddr, to);
     99 	kunmap_atomic(vfrom, KM_USER0);
    100 	kunmap_atomic(vto, KM_USER1);
    101 	/* Make sure this page is cleared on other CPU's too before using it */
    102 	smp_wmb();
    103 }
    104 
    105 static inline void copy_highpage(struct page *to, struct page *from)
    106 {
    107 	char *vfrom, *vto;
    108 
    109 	vfrom = kmap_atomic(from, KM_USER0);
    110 	vto = kmap_atomic(to, KM_USER1);
    111 	copy_page(vto, vfrom);
    112 	kunmap_atomic(vfrom, KM_USER0);
    113 	kunmap_atomic(vto, KM_USER1);
    114 }
    115 
    116 #endif /* _LINUX_HIGHMEM_H */
    117