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