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
flush_anon_page(struct vm_area_struct * vma,struct page * page,unsigned long vmaddr)14 static 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
flush_kernel_dcache_page(struct page * page)20 static inline void flush_kernel_dcache_page(struct page *page)
21 {
22 }
flush_kernel_vmap_range(void * vaddr,int size)23 static inline void flush_kernel_vmap_range(void *vaddr, int size)
24 {
25 }
invalidate_kernel_vmap_range(void * vaddr,int size)26 static 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 */
37 unsigned int nr_free_highpages(void);
38 extern unsigned long totalhigh_pages;
39
40 void kmap_flush_unused(void);
41
42 struct page *kmap_to_page(void *addr);
43
44 #else /* CONFIG_HIGHMEM */
45
nr_free_highpages(void)46 static inline unsigned int nr_free_highpages(void) { return 0; }
47
kmap_to_page(void * addr)48 static 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
kmap(struct page * page)56 static inline void *kmap(struct page *page)
57 {
58 might_sleep();
59 return page_address(page);
60 }
61
kunmap(struct page * page)62 static inline void kunmap(struct page *page)
63 {
64 }
65
kmap_atomic(struct page * page)66 static 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
__kunmap_atomic(void * addr)74 static 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
89 DECLARE_PER_CPU(int, __kmap_atomic_idx);
90
kmap_atomic_idx_push(void)91 static 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
kmap_atomic_idx(void)102 static inline int kmap_atomic_idx(void)
103 {
104 return __this_cpu_read(__kmap_atomic_idx) - 1;
105 }
106
kmap_atomic_idx_pop(void)107 static 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) \
125 do { \
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
clear_user_highpage(struct page * page,unsigned long vaddr)133 static 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 */
156 static inline struct page *
__alloc_zeroed_user_highpage(gfp_t movableflags,struct vm_area_struct * vma,unsigned long vaddr)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 */
179 static inline struct page *
alloc_zeroed_user_highpage_movable(struct vm_area_struct * vma,unsigned long vaddr)180 alloc_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
clear_highpage(struct page * page)186 static inline void clear_highpage(struct page *page)
187 {
188 void *kaddr = kmap_atomic(page);
189 clear_page(kaddr);
190 kunmap_atomic(kaddr);
191 }
192
zero_user_segments(struct page * page,unsigned start1,unsigned end1,unsigned start2,unsigned end2)193 static 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
zero_user_segment(struct page * page,unsigned start,unsigned end)211 static 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
zero_user(struct page * page,unsigned start,unsigned size)217 static 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
copy_user_highpage(struct page * to,struct page * from,unsigned long vaddr,struct vm_area_struct * vma)225 static 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
copy_highpage(struct page * to,struct page * from)239 static 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 */
251