Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
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 */
15unsigned int nr_free_highpages(void);
16
17#else /* CONFIG_HIGHMEM */
18
19static inline unsigned int nr_free_highpages(void) { return 0; }
20
21static 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_to_page(ptr) virt_to_page(ptr)
32
33#endif /* CONFIG_HIGHMEM */
34
35/* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */
36static inline void clear_user_highpage(struct page *page, unsigned long vaddr)
37{
38 void *addr = kmap_atomic(page, KM_USER0);
39 clear_user_page(addr, vaddr, page);
40 kunmap_atomic(addr, KM_USER0);
41 /* Make sure this page is cleared on other CPU's too before using it */
42 smp_wmb();
43}
44
45#ifndef __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE
46static inline struct page *
47alloc_zeroed_user_highpage(struct vm_area_struct *vma, unsigned long vaddr)
48{
49 struct page *page = alloc_page_vma(GFP_HIGHUSER, vma, vaddr);
50
51 if (page)
52 clear_user_highpage(page, vaddr);
53
54 return page;
55}
56#endif
57
58static inline void clear_highpage(struct page *page)
59{
60 void *kaddr = kmap_atomic(page, KM_USER0);
61 clear_page(kaddr);
62 kunmap_atomic(kaddr, KM_USER0);
63}
64
65/*
66 * Same but also flushes aliased cache contents to RAM.
67 */
68static inline void memclear_highpage_flush(struct page *page, unsigned int offset, unsigned int size)
69{
70 void *kaddr;
71
72 BUG_ON(offset + size > PAGE_SIZE);
73
74 kaddr = kmap_atomic(page, KM_USER0);
75 memset((char *)kaddr + offset, 0, size);
76 flush_dcache_page(page);
77 kunmap_atomic(kaddr, KM_USER0);
78}
79
80static inline void copy_user_highpage(struct page *to, struct page *from, unsigned long vaddr)
81{
82 char *vfrom, *vto;
83
84 vfrom = kmap_atomic(from, KM_USER0);
85 vto = kmap_atomic(to, KM_USER1);
86 copy_user_page(vto, vfrom, vaddr, to);
87 kunmap_atomic(vfrom, KM_USER0);
88 kunmap_atomic(vto, KM_USER1);
89 /* Make sure this page is cleared on other CPU's too before using it */
90 smp_wmb();
91}
92
93static inline void copy_highpage(struct page *to, struct page *from)
94{
95 char *vfrom, *vto;
96
97 vfrom = kmap_atomic(from, KM_USER0);
98 vto = kmap_atomic(to, KM_USER1);
99 copy_page(vto, vfrom);
100 kunmap_atomic(vfrom, KM_USER0);
101 kunmap_atomic(vto, KM_USER1);
102}
103
104#endif /* _LINUX_HIGHMEM_H */