Linux kernel mirror (for testing)
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1#ifndef _LINUX_HIGHMEM_H
2#define _LINUX_HIGHMEM_H
3
4#include <linux/fs.h>
5#include <linux/kernel.h>
6#include <linux/bug.h>
7#include <linux/mm.h>
8#include <linux/uaccess.h>
9#include <linux/hardirq.h>
10
11#include <asm/cacheflush.h>
12
13#ifndef ARCH_HAS_FLUSH_ANON_PAGE
14static inline void flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned long vmaddr)
15{
16}
17#endif
18
19#ifndef ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE
20static inline void flush_kernel_dcache_page(struct page *page)
21{
22}
23static inline void flush_kernel_vmap_range(void *vaddr, int size)
24{
25}
26static inline void invalidate_kernel_vmap_range(void *vaddr, int size)
27{
28}
29#endif
30
31#include <asm/kmap_types.h>
32
33#ifdef CONFIG_HIGHMEM
34#include <asm/highmem.h>
35
36/* declarations for linux/mm/highmem.c */
37unsigned int nr_free_highpages(void);
38extern unsigned long totalhigh_pages;
39
40void kmap_flush_unused(void);
41
42struct page *kmap_to_page(void *addr);
43
44#else /* CONFIG_HIGHMEM */
45
46static inline unsigned int nr_free_highpages(void) { return 0; }
47
48static inline struct page *kmap_to_page(void *addr)
49{
50 return virt_to_page(addr);
51}
52
53#define totalhigh_pages 0UL
54
55#ifndef ARCH_HAS_KMAP
56static inline void *kmap(struct page *page)
57{
58 might_sleep();
59 return page_address(page);
60}
61
62static inline void kunmap(struct page *page)
63{
64}
65
66static inline void *kmap_atomic(struct page *page)
67{
68 preempt_disable();
69 pagefault_disable();
70 return page_address(page);
71}
72#define kmap_atomic_prot(page, prot) kmap_atomic(page)
73
74static inline void __kunmap_atomic(void *addr)
75{
76 pagefault_enable();
77 preempt_enable();
78}
79
80#define kmap_atomic_pfn(pfn) kmap_atomic(pfn_to_page(pfn))
81
82#define kmap_flush_unused() do {} while(0)
83#endif
84
85#endif /* CONFIG_HIGHMEM */
86
87#if defined(CONFIG_HIGHMEM) || defined(CONFIG_X86_32)
88
89DECLARE_PER_CPU(int, __kmap_atomic_idx);
90
91static inline int kmap_atomic_idx_push(void)
92{
93 int idx = __this_cpu_inc_return(__kmap_atomic_idx) - 1;
94
95#ifdef CONFIG_DEBUG_HIGHMEM
96 WARN_ON_ONCE(in_irq() && !irqs_disabled());
97 BUG_ON(idx >= KM_TYPE_NR);
98#endif
99 return idx;
100}
101
102static inline int kmap_atomic_idx(void)
103{
104 return __this_cpu_read(__kmap_atomic_idx) - 1;
105}
106
107static inline void kmap_atomic_idx_pop(void)
108{
109#ifdef CONFIG_DEBUG_HIGHMEM
110 int idx = __this_cpu_dec_return(__kmap_atomic_idx);
111
112 BUG_ON(idx < 0);
113#else
114 __this_cpu_dec(__kmap_atomic_idx);
115#endif
116}
117
118#endif
119
120/*
121 * Prevent people trying to call kunmap_atomic() as if it were kunmap()
122 * kunmap_atomic() should get the return value of kmap_atomic, not the page.
123 */
124#define kunmap_atomic(addr) \
125do { \
126 BUILD_BUG_ON(__same_type((addr), struct page *)); \
127 __kunmap_atomic(addr); \
128} while (0)
129
130
131/* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */
132#ifndef clear_user_highpage
133static inline void clear_user_highpage(struct page *page, unsigned long vaddr)
134{
135 void *addr = kmap_atomic(page);
136 clear_user_page(addr, vaddr, page);
137 kunmap_atomic(addr);
138}
139#endif
140
141#ifndef __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE
142/**
143 * __alloc_zeroed_user_highpage - Allocate a zeroed HIGHMEM page for a VMA with caller-specified movable GFP flags
144 * @movableflags: The GFP flags related to the pages future ability to move like __GFP_MOVABLE
145 * @vma: The VMA the page is to be allocated for
146 * @vaddr: The virtual address the page will be inserted into
147 *
148 * This function will allocate a page for a VMA but the caller is expected
149 * to specify via movableflags whether the page will be movable in the
150 * future or not
151 *
152 * An architecture may override this function by defining
153 * __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE and providing their own
154 * implementation.
155 */
156static inline struct page *
157__alloc_zeroed_user_highpage(gfp_t movableflags,
158 struct vm_area_struct *vma,
159 unsigned long vaddr)
160{
161 struct page *page = alloc_page_vma(GFP_HIGHUSER | movableflags,
162 vma, vaddr);
163
164 if (page)
165 clear_user_highpage(page, vaddr);
166
167 return page;
168}
169#endif
170
171/**
172 * alloc_zeroed_user_highpage_movable - Allocate a zeroed HIGHMEM page for a VMA that the caller knows can move
173 * @vma: The VMA the page is to be allocated for
174 * @vaddr: The virtual address the page will be inserted into
175 *
176 * This function will allocate a page for a VMA that the caller knows will
177 * be able to migrate in the future using move_pages() or reclaimed
178 */
179static inline struct page *
180alloc_zeroed_user_highpage_movable(struct vm_area_struct *vma,
181 unsigned long vaddr)
182{
183 return __alloc_zeroed_user_highpage(__GFP_MOVABLE, vma, vaddr);
184}
185
186static inline void clear_highpage(struct page *page)
187{
188 void *kaddr = kmap_atomic(page);
189 clear_page(kaddr);
190 kunmap_atomic(kaddr);
191}
192
193static inline void zero_user_segments(struct page *page,
194 unsigned start1, unsigned end1,
195 unsigned start2, unsigned end2)
196{
197 void *kaddr = kmap_atomic(page);
198
199 BUG_ON(end1 > PAGE_SIZE || end2 > PAGE_SIZE);
200
201 if (end1 > start1)
202 memset(kaddr + start1, 0, end1 - start1);
203
204 if (end2 > start2)
205 memset(kaddr + start2, 0, end2 - start2);
206
207 kunmap_atomic(kaddr);
208 flush_dcache_page(page);
209}
210
211static inline void zero_user_segment(struct page *page,
212 unsigned start, unsigned end)
213{
214 zero_user_segments(page, start, end, 0, 0);
215}
216
217static inline void zero_user(struct page *page,
218 unsigned start, unsigned size)
219{
220 zero_user_segments(page, start, start + size, 0, 0);
221}
222
223#ifndef __HAVE_ARCH_COPY_USER_HIGHPAGE
224
225static inline void copy_user_highpage(struct page *to, struct page *from,
226 unsigned long vaddr, struct vm_area_struct *vma)
227{
228 char *vfrom, *vto;
229
230 vfrom = kmap_atomic(from);
231 vto = kmap_atomic(to);
232 copy_user_page(vto, vfrom, vaddr, to);
233 kunmap_atomic(vto);
234 kunmap_atomic(vfrom);
235}
236
237#endif
238
239static inline void copy_highpage(struct page *to, struct page *from)
240{
241 char *vfrom, *vto;
242
243 vfrom = kmap_atomic(from);
244 vto = kmap_atomic(to);
245 copy_page(vto, vfrom);
246 kunmap_atomic(vto);
247 kunmap_atomic(vfrom);
248}
249
250#endif /* _LINUX_HIGHMEM_H */