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_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 */
37static 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
47static inline struct page *
48alloc_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
59static 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 */
69static 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
81static 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
94static 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 */