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 #include <linux/hardirq.h>
   9
  10 #include <asm/cacheflush.h>
  11
  12 #ifndef ARCH_HAS_FLUSH_ANON_PAGE
  13 static inline void flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned long vmaddr)
  14 {
  15 }
  16 #endif
  17
  18 #ifndef ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE
  19 static inline void flush_kernel_dcache_page(struct page *page)
  20 {
  21 }
  22 static inline void flush_kernel_vmap_range(void *vaddr, int size)
  23 {
  24 }
  25 static inline void invalidate_kernel_vmap_range(void *vaddr, int size)
  26 {
  27 }
  28 #endif
  29
  30 #include <asm/kmap_types.h>
  31
  32 #ifdef CONFIG_HIGHMEM
  33 #include <asm/highmem.h>
  34
  35 /* declarations for linux/mm/highmem.c */
  36 unsigned int nr_free_highpages(void);
  37 extern unsigned long totalhigh_pages;
  38
  39 void kmap_flush_unused(void);
  40
  41 #else /* CONFIG_HIGHMEM */
  42
  43 static inline unsigned int nr_free_highpages(void) { return 0; }
  44
  45 #define totalhigh_pages 0UL
  46
  47 #ifndef ARCH_HAS_KMAP
  48 static inline void *kmap(struct page *page)
  49 {
  50         might_sleep();
  51         return page_address(page);
  52 }
  53
  54 static inline void kunmap(struct page *page)
  55 {
  56 }
  57
  58 static inline void *__kmap_atomic(struct page *page)
  59 {
  60         pagefault_disable();
  61         return page_address(page);
  62 }
  63 #define kmap_atomic_prot(page, prot)    __kmap_atomic(page)
  64
  65 static inline void __kunmap_atomic(void *addr)
  66 {
  67         pagefault_enable();
  68 }
  69
  70 #define kmap_atomic_pfn(pfn)    kmap_atomic(pfn_to_page(pfn))
  71 #define kmap_atomic_to_page(ptr)        virt_to_page(ptr)
  72
  73 #define kmap_flush_unused()     do {} while(0)
  74 #endif
  75
  76 #endif /* CONFIG_HIGHMEM */
  77
  78 #if defined(CONFIG_HIGHMEM) || defined(CONFIG_X86_32)
  79
  80 DECLARE_PER_CPU(int, __kmap_atomic_idx);
  81
  82 static inline int kmap_atomic_idx_push(void)
  83 {
  84         int idx = __this_cpu_inc_return(__kmap_atomic_idx) - 1;
  85
  86 #ifdef CONFIG_DEBUG_HIGHMEM
  87         WARN_ON_ONCE(in_irq() && !irqs_disabled());
  88         BUG_ON(idx > KM_TYPE_NR);
  89 #endif
  90         return idx;
  91 }
  92
  93 static inline int kmap_atomic_idx(void)
  94 {
  95         return __this_cpu_read(__kmap_atomic_idx) - 1;
  96 }
  97
  98 static inline void kmap_atomic_idx_pop(void)
  99 {
 100 #ifdef CONFIG_DEBUG_HIGHMEM
 101         int idx = __this_cpu_dec_return(__kmap_atomic_idx);
 102
 103         BUG_ON(idx < 0);
 104 #else
 105         __this_cpu_dec(__kmap_atomic_idx);
 106 #endif
 107 }
 108
 109 #endif
 110
 111 /*
 112  * NOTE:
 113  * kmap_atomic() and kunmap_atomic() with two arguments are deprecated.
 114  * We only keep them for backward compatibility, any usage of them
 115  * are now warned.
 116  */
 117
 118 #define PASTE(a, b) a ## b
 119 #define PASTE2(a, b) PASTE(a, b)
 120
 121 #define NARG_(_2, _1, n, ...) n
 122 #define NARG(...) NARG_(__VA_ARGS__, 2, 1, :)
 123
 124 static inline void *kmap_atomic(struct page *page)
 125 {
 126         return __kmap_atomic(page);
 127 }
 128
 129 static inline void __deprecated *kmap_atomic_deprecated(struct page *page,
 130                                                         enum km_type km)
 131 {
 132         return __kmap_atomic(page);
 133 }
 134
 135 #define kmap_atomic1(...) kmap_atomic(__VA_ARGS__)
 136 #define kmap_atomic2(...) kmap_atomic_deprecated(__VA_ARGS__)
 137 #define kmap_atomic(...) PASTE2(kmap_atomic, NARG(__VA_ARGS__)(__VA_ARGS__))
 138
 139 static inline void __deprecated __kunmap_atomic_deprecated(void *addr,
 140                                                         enum km_type km)
 141 {
 142         __kunmap_atomic(addr);
 143 }
 144
 145 /*
 146  * Prevent people trying to call kunmap_atomic() as if it were kunmap()
 147  * kunmap_atomic() should get the return value of kmap_atomic, not the page.
 148  */
 149 #define kunmap_atomic_deprecated(addr, km)                      \
 150 do {                                                            \
 151         BUILD_BUG_ON(__same_type((addr), struct page *));       \
 152         __kunmap_atomic_deprecated(addr, km);                   \
 153 } while (0)
 154
 155 #define kunmap_atomic_withcheck(addr)                           \
 156 do {                                                            \
 157         BUILD_BUG_ON(__same_type((addr), struct page *));       \
 158         __kunmap_atomic(addr);                                  \
 159 } while (0)
 160
 161 #define kunmap_atomic1(...) kunmap_atomic_withcheck(__VA_ARGS__)
 162 #define kunmap_atomic2(...) kunmap_atomic_deprecated(__VA_ARGS__)
 163 #define kunmap_atomic(...) PASTE2(kunmap_atomic, NARG(__VA_ARGS__)(__VA_ARGS__))
 164 /**** End of C pre-processor tricks for deprecated macros ****/
 165
 166 /* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */
 167 #ifndef clear_user_highpage
 168 static inline void clear_user_highpage(struct page *page, unsigned long vaddr)
 169 {
 170         void *addr = kmap_atomic(page);
 171         clear_user_page(addr, vaddr, page);
 172         kunmap_atomic(addr);
 173 }
 174 #endif
 175
 176 #ifndef __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE
 177 /**
 178  * __alloc_zeroed_user_highpage - Allocate a zeroed HIGHMEM page for a VMA with caller-specified movable GFP flags
 179  * @movableflags: The GFP flags related to the pages future ability to move like __GFP_MOVABLE
 180  * @vma: The VMA the page is to be allocated for
 181  * @vaddr: The virtual address the page will be inserted into
 182  *
 183  * This function will allocate a page for a VMA but the caller is expected
 184  * to specify via movableflags whether the page will be movable in the
 185  * future or not
 186  *
 187  * An architecture may override this function by defining
 188  * __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE and providing their own
 189  * implementation.
 190  */
 191 static inline struct page *
 192 __alloc_zeroed_user_highpage(gfp_t movableflags,
 193                         struct vm_area_struct *vma,
 194                         unsigned long vaddr)
 195 {
 196         struct page *page = alloc_page_vma(GFP_HIGHUSER | movableflags,
 197                         vma, vaddr);
 198
 199         if (page)
 200                 clear_user_highpage(page, vaddr);
 201
 202         return page;
 203 }
 204 #endif
 205
 206 /**
 207  * alloc_zeroed_user_highpage_movable - Allocate a zeroed HIGHMEM page for a VMA that the caller knows can move
 208  * @vma: The VMA the page is to be allocated for
 209  * @vaddr: The virtual address the page will be inserted into
 210  *
 211  * This function will allocate a page for a VMA that the caller knows will
 212  * be able to migrate in the future using move_pages() or reclaimed
 213  */
 214 static inline struct page *
 215 alloc_zeroed_user_highpage_movable(struct vm_area_struct *vma,
 216                                         unsigned long vaddr)
 217 {
 218         return __alloc_zeroed_user_highpage(__GFP_MOVABLE, vma, vaddr);
 219 }
 220
 221 static inline void clear_highpage(struct page *page)
 222 {
 223         void *kaddr = kmap_atomic(page);
 224         clear_page(kaddr);
 225         kunmap_atomic(kaddr);
 226 }
 227
 228 static inline void zero_user_segments(struct page *page,
 229         unsigned start1, unsigned end1,
 230         unsigned start2, unsigned end2)
 231 {
 232         void *kaddr = kmap_atomic(page);
 233
 234         BUG_ON(end1 > PAGE_SIZE || end2 > PAGE_SIZE);
 235
 236         if (end1 > start1)
 237                 memset(kaddr + start1, 0, end1 - start1);
 238
 239         if (end2 > start2)
 240                 memset(kaddr + start2, 0, end2 - start2);
 241
 242         kunmap_atomic(kaddr);
 243         flush_dcache_page(page);
 244 }
 245
 246 static inline void zero_user_segment(struct page *page,
 247         unsigned start, unsigned end)
 248 {
 249         zero_user_segments(page, start, end, 0, 0);
 250 }
 251
 252 static inline void zero_user(struct page *page,
 253         unsigned start, unsigned size)
 254 {
 255         zero_user_segments(page, start, start + size, 0, 0);
 256 }
 257
 258 static inline void __deprecated memclear_highpage_flush(struct page *page,
 259                         unsigned int offset, unsigned int size)
 260 {
 261         zero_user(page, offset, size);
 262 }
 263
 264 #ifndef __HAVE_ARCH_COPY_USER_HIGHPAGE
 265
 266 static inline void copy_user_highpage(struct page *to, struct page *from,
 267         unsigned long vaddr, struct vm_area_struct *vma)
 268 {
 269         char *vfrom, *vto;
 270
 271         vfrom = kmap_atomic(from);
 272         vto = kmap_atomic(to);
 273         copy_user_page(vto, vfrom, vaddr, to);
 274         kunmap_atomic(vto);
 275         kunmap_atomic(vfrom);
 276 }
 277
 278 #endif
 279
 280 static inline void copy_highpage(struct page *to, struct page *from)
 281 {
 282         char *vfrom, *vto;
 283
 284         vfrom = kmap_atomic(from);
 285         vto = kmap_atomic(to);
 286         copy_page(vto, vfrom);
 287         kunmap_atomic(vto);
 288         kunmap_atomic(vfrom);
 289 }
 290
 291 #endif /* _LINUX_HIGHMEM_H */