linux/include/linux/highmem.h
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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        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
 222static inline void __deprecated memclear_highpage_flush(struct page *page,
 223                        unsigned int offset, unsigned int size)
 224{
 225        zero_user(page, offset, size);
 226}
 227
 228#ifndef __HAVE_ARCH_COPY_USER_HIGHPAGE
 229
 230static inline void copy_user_highpage(struct page *to, struct page *from,
 231        unsigned long vaddr, struct vm_area_struct *vma)
 232{
 233        char *vfrom, *vto;
 234
 235        vfrom = kmap_atomic(from);
 236        vto = kmap_atomic(to);
 237        copy_user_page(vto, vfrom, vaddr, to);
 238        kunmap_atomic(vto);
 239        kunmap_atomic(vfrom);
 240}
 241
 242#endif
 243
 244static inline void copy_highpage(struct page *to, struct page *from)
 245{
 246        char *vfrom, *vto;
 247
 248        vfrom = kmap_atomic(from);
 249        vto = kmap_atomic(to);
 250        copy_page(vto, vfrom);
 251        kunmap_atomic(vto);
 252        kunmap_atomic(vfrom);
 253}
 254
 255#endif /* _LINUX_HIGHMEM_H */
 256
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