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	pagefault_disable();
69	return page_address(page);
70}
71#define kmap_atomic_prot(page, prot)	kmap_atomic(page)
72
73static inline void __kunmap_atomic(void *addr)
74{
75	pagefault_enable();
76}
77
78#define kmap_atomic_pfn(pfn)	kmap_atomic(pfn_to_page(pfn))
79#define kmap_atomic_to_page(ptr)	virt_to_page(ptr)
80
81#define kmap_flush_unused()	do {} while(0)
82#endif
83
84#endif /* CONFIG_HIGHMEM */
85
86#if defined(CONFIG_HIGHMEM) || defined(CONFIG_X86_32)
87
88DECLARE_PER_CPU(int, __kmap_atomic_idx);
89
90static inline int kmap_atomic_idx_push(void)
91{
92	int idx = __this_cpu_inc_return(__kmap_atomic_idx) - 1;
93
94#ifdef CONFIG_DEBUG_HIGHMEM
95	WARN_ON_ONCE(in_irq() && !irqs_disabled());
96	BUG_ON(idx >= KM_TYPE_NR);
97#endif
98	return idx;
99}
100
101static inline int kmap_atomic_idx(void)
102{
103	return __this_cpu_read(__kmap_atomic_idx) - 1;
104}
105
106static inline void kmap_atomic_idx_pop(void)
107{
108#ifdef CONFIG_DEBUG_HIGHMEM
109	int idx = __this_cpu_dec_return(__kmap_atomic_idx);
110
111	BUG_ON(idx < 0);
112#else
113	__this_cpu_dec(__kmap_atomic_idx);
114#endif
115}
116
117#endif
118
119/*
120 * Prevent people trying to call kunmap_atomic() as if it were kunmap()
121 * kunmap_atomic() should get the return value of kmap_atomic, not the page.
122 */
123#define kunmap_atomic(addr)                                     \
124do {                                                            \
125	BUILD_BUG_ON(__same_type((addr), struct page *));       \
126	__kunmap_atomic(addr);                                  \
127} while (0)
128
129
130/* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */
131#ifndef clear_user_highpage
132static inline void clear_user_highpage(struct page *page, unsigned long vaddr)
133{
134	void *addr = kmap_atomic(page);
135	clear_user_page(addr, vaddr, page);
136	kunmap_atomic(addr);
137}
138#endif
139
140#ifndef __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE
141/**
142 * __alloc_zeroed_user_highpage - Allocate a zeroed HIGHMEM page for a VMA with caller-specified movable GFP flags
143 * @movableflags: The GFP flags related to the pages future ability to move like __GFP_MOVABLE
144 * @vma: The VMA the page is to be allocated for
145 * @vaddr: The virtual address the page will be inserted into
146 *
147 * This function will allocate a page for a VMA but the caller is expected
148 * to specify via movableflags whether the page will be movable in the
149 * future or not
150 *
151 * An architecture may override this function by defining
152 * __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE and providing their own
153 * implementation.
154 */
155static inline struct page *
156__alloc_zeroed_user_highpage(gfp_t movableflags,
157			struct vm_area_struct *vma,
158			unsigned long vaddr)
159{
160	struct page *page = alloc_page_vma(GFP_HIGHUSER | movableflags,
161			vma, vaddr);
162
163	if (page)
164		clear_user_highpage(page, vaddr);
165
166	return page;
167}
168#endif
169
170/**
171 * alloc_zeroed_user_highpage_movable - Allocate a zeroed HIGHMEM page for a VMA that the caller knows can move
172 * @vma: The VMA the page is to be allocated for
173 * @vaddr: The virtual address the page will be inserted into
174 *
175 * This function will allocate a page for a VMA that the caller knows will
176 * be able to migrate in the future using move_pages() or reclaimed
177 */
178static inline struct page *
179alloc_zeroed_user_highpage_movable(struct vm_area_struct *vma,
180					unsigned long vaddr)
181{
182	return __alloc_zeroed_user_highpage(__GFP_MOVABLE, vma, vaddr);
183}
184
185static inline void clear_highpage(struct page *page)
186{
187	void *kaddr = kmap_atomic(page);
188	clear_page(kaddr);
189	kunmap_atomic(kaddr);
190}
191
192static inline void zero_user_segments(struct page *page,
193	unsigned start1, unsigned end1,
194	unsigned start2, unsigned end2)
195{
196	void *kaddr = kmap_atomic(page);
197
198	BUG_ON(end1 > PAGE_SIZE || end2 > PAGE_SIZE);
199
200	if (end1 > start1)
201		memset(kaddr + start1, 0, end1 - start1);
202
203	if (end2 > start2)
204		memset(kaddr + start2, 0, end2 - start2);
205
206	kunmap_atomic(kaddr);
207	flush_dcache_page(page);
208}
209
210static inline void zero_user_segment(struct page *page,
211	unsigned start, unsigned end)
212{
213	zero_user_segments(page, start, end, 0, 0);
214}
215
216static inline void zero_user(struct page *page,
217	unsigned start, unsigned size)
218{
219	zero_user_segments(page, start, start + size, 0, 0);
220}
221
222#ifndef __HAVE_ARCH_COPY_USER_HIGHPAGE
223
224static inline void copy_user_highpage(struct page *to, struct page *from,
225	unsigned long vaddr, struct vm_area_struct *vma)
226{
227	char *vfrom, *vto;
228
229	vfrom = kmap_atomic(from);
230	vto = kmap_atomic(to);
231	copy_user_page(vto, vfrom, vaddr, to);
232	kunmap_atomic(vto);
233	kunmap_atomic(vfrom);
234}
235
236#endif
237
238static inline void copy_highpage(struct page *to, struct page *from)
239{
240	char *vfrom, *vto;
241
242	vfrom = kmap_atomic(from);
243	vto = kmap_atomic(to);
244	copy_page(vto, vfrom);
245	kunmap_atomic(vto);
246	kunmap_atomic(vfrom);
247}
248
249#endif /* _LINUX_HIGHMEM_H */
250