include/linux/highmem.h

   1 #ifndef _LINUX_HIGHMEM_H
   2 #define _LINUX_HIGHMEM_H
   3
   4 #include <linux/fs.h>
   5 #include <linux/kernel.h>
   6 #include <linux/mm.h>
   7 #include <linux/uaccess.h>
   8
   9 #include <asm/cacheflush.h>
  10
  11 #ifndef ARCH_HAS_FLUSH_ANON_PAGE
  12 static inline void flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned long vmaddr)
  13 {
  14 }
  15 #endif
  16
  17 #ifndef ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE
  18 static inline void flush_kernel_dcache_page(struct page *page)
  19 {
  20 }
  21 static inline void flush_kernel_vmap_range(void *vaddr, int size)
  22 {
  23 }
  24 static inline void invalidate_kernel_vmap_range(void *vaddr, int size)
  25 {
  26 }
  27 #endif
  28
  29 #include <asm/kmap_types.h>
  30
  31 #ifdef CONFIG_HIGHMEM
  32 #include <asm/highmem.h>
  33
  34 /* declarations for linux/mm/highmem.c */
  35 unsigned int nr_free_highpages(void);
  36 extern unsigned long totalhigh_pages;
  37
  38 void kmap_flush_unused(void);
  39
  40 DECLARE_PER_CPU(int, __kmap_atomic_idx);
  41
  42 static inline int kmap_atomic_idx_push(void)
  43 {
  44         int idx = __get_cpu_var(__kmap_atomic_idx)++;
  45 #ifdef CONFIG_DEBUG_HIGHMEM
  46         WARN_ON_ONCE(in_irq() && !irqs_disabled());
  47         BUG_ON(idx > KM_TYPE_NR);
  48 #endif
  49         return idx;
  50 }
  51
  52 static inline int kmap_atomic_idx_pop(void)
  53 {
  54         int idx = --__get_cpu_var(__kmap_atomic_idx);
  55 #ifdef CONFIG_DEBUG_HIGHMEM
  56         BUG_ON(idx < 0);
  57 #endif
  58         return idx;
  59 }
  60
  61 #else /* CONFIG_HIGHMEM */
  62
  63 static inline unsigned int nr_free_highpages(void) { return 0; }
  64
  65 #define totalhigh_pages 0UL
  66
  67 #ifndef ARCH_HAS_KMAP
  68 static inline void *kmap(struct page *page)
  69 {
  70         might_sleep();
  71         return page_address(page);
  72 }
  73
  74 static inline void kunmap(struct page *page)
  75 {
  76 }
  77
  78 static inline void *__kmap_atomic(struct page *page)
  79 {
  80         pagefault_disable();
  81         return page_address(page);
  82 }
  83 #define kmap_atomic_prot(page, prot)    __kmap_atomic(page)
  84
  85 static inline void __kunmap_atomic(void *addr)
  86 {
  87         pagefault_enable();
  88 }
  89
  90 #define kmap_atomic_pfn(pfn)    kmap_atomic(pfn_to_page(pfn))
  91 #define kmap_atomic_to_page(ptr)        virt_to_page(ptr)
  92
  93 #define kmap_flush_unused()     do {} while(0)
  94 #endif
  95
  96 #endif /* CONFIG_HIGHMEM */
  97
  98 /*
  99  * Make both: kmap_atomic(page, idx) and kmap_atomic(page) work.
 100  */
 101 #define kmap_atomic(page, args...) __kmap_atomic(page)
 102
 103 /*
 104  * Prevent people trying to call kunmap_atomic() as if it were kunmap()
 105  * kunmap_atomic() should get the return value of kmap_atomic, not the page.
 106  */
 107 #define kunmap_atomic(addr, args...)                            \
 108 do {                                                            \
 109         BUILD_BUG_ON(__same_type((addr), struct page *));       \
 110         __kunmap_atomic(addr);                                  \
 111 } while (0)
 112
 113 /* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */
 114 #ifndef clear_user_highpage
 115 static inline void clear_user_highpage(struct page *page, unsigned long vaddr)
 116 {
 117         void *addr = kmap_atomic(page, KM_USER0);
 118         clear_user_page(addr, vaddr, page);
 119         kunmap_atomic(addr, KM_USER0);
 120 }
 121 #endif
 122
 123 #ifndef __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE
 124 /**
 125  * __alloc_zeroed_user_highpage - Allocate a zeroed HIGHMEM page for a VMA with caller-specified movable GFP flags
 126  * @movableflags: The GFP flags related to the pages future ability to move like __GFP_MOVABLE
 127  * @vma: The VMA the page is to be allocated for
 128  * @vaddr: The virtual address the page will be inserted into
 129  *
 130  * This function will allocate a page for a VMA but the caller is expected
 131  * to specify via movableflags whether the page will be movable in the
 132  * future or not
 133  *
 134  * An architecture may override this function by defining
 135  * __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE and providing their own
 136  * implementation.
 137  */
 138 static inline struct page *
 139 __alloc_zeroed_user_highpage(gfp_t movableflags,
 140                         struct vm_area_struct *vma,
 141                         unsigned long vaddr)
 142 {
 143         struct page *page = alloc_page_vma(GFP_HIGHUSER | movableflags,
 144                         vma, vaddr);
 145
 146         if (page)
 147                 clear_user_highpage(page, vaddr);
 148
 149         return page;
 150 }
 151 #endif
 152
 153 /**
 154  * alloc_zeroed_user_highpage_movable - Allocate a zeroed HIGHMEM page for a VMA that the caller knows can move
 155  * @vma: The VMA the page is to be allocated for
 156  * @vaddr: The virtual address the page will be inserted into
 157  *
 158  * This function will allocate a page for a VMA that the caller knows will
 159  * be able to migrate in the future using move_pages() or reclaimed
 160  */
 161 static inline struct page *
 162 alloc_zeroed_user_highpage_movable(struct vm_area_struct *vma,
 163                                         unsigned long vaddr)
 164 {
 165         return __alloc_zeroed_user_highpage(__GFP_MOVABLE, vma, vaddr);
 166 }
 167
 168 static inline void clear_highpage(struct page *page)
 169 {
 170         void *kaddr = kmap_atomic(page, KM_USER0);
 171         clear_page(kaddr);
 172         kunmap_atomic(kaddr, KM_USER0);
 173 }
 174
 175 static inline void zero_user_segments(struct page *page,
 176         unsigned start1, unsigned end1,
 177         unsigned start2, unsigned end2)
 178 {
 179         void *kaddr = kmap_atomic(page, KM_USER0);
 180
 181         BUG_ON(end1 > PAGE_SIZE || end2 > PAGE_SIZE);
 182
 183         if (end1 > start1)
 184                 memset(kaddr + start1, 0, end1 - start1);
 185
 186         if (end2 > start2)
 187                 memset(kaddr + start2, 0, end2 - start2);
 188
 189         kunmap_atomic(kaddr, KM_USER0);
 190         flush_dcache_page(page);
 191 }
 192
 193 static inline void zero_user_segment(struct page *page,
 194         unsigned start, unsigned end)
 195 {
 196         zero_user_segments(page, start, end, 0, 0);
 197 }
 198
 199 static inline void zero_user(struct page *page,
 200         unsigned start, unsigned size)
 201 {
 202         zero_user_segments(page, start, start + size, 0, 0);
 203 }
 204
 205 static inline void __deprecated memclear_highpage_flush(struct page *page,
 206                         unsigned int offset, unsigned int size)
 207 {
 208         zero_user(page, offset, size);
 209 }
 210
 211 #ifndef __HAVE_ARCH_COPY_USER_HIGHPAGE
 212
 213 static inline void copy_user_highpage(struct page *to, struct page *from,
 214         unsigned long vaddr, struct vm_area_struct *vma)
 215 {
 216         char *vfrom, *vto;
 217
 218         vfrom = kmap_atomic(from, KM_USER0);
 219         vto = kmap_atomic(to, KM_USER1);
 220         copy_user_page(vto, vfrom, vaddr, to);
 221         kunmap_atomic(vto, KM_USER1);
 222         kunmap_atomic(vfrom, KM_USER0);
 223 }
 224
 225 #endif
 226
 227 static inline void copy_highpage(struct page *to, struct page *from)
 228 {
 229         char *vfrom, *vto;
 230
 231         vfrom = kmap_atomic(from, KM_USER0);
 232         vto = kmap_atomic(to, KM_USER1);
 233         copy_page(vto, vfrom);
 234         kunmap_atomic(vto, KM_USER1);
 235         kunmap_atomic(vfrom, KM_USER0);
 236 }
 237
 238 #endif /* _LINUX_HIGHMEM_H */