include/asm-x86/fixmap.h

   1 #ifndef _ASM_FIXMAP_H
   2 #define _ASM_FIXMAP_H
   3
   4 #ifdef CONFIG_X86_32
   5 # include "fixmap_32.h"
   6 #else
   7 # include "fixmap_64.h"
   8 #endif
   9
  10 extern int fixmaps_set;
  11
  12 void __native_set_fixmap(enum fixed_addresses idx, pte_t pte);
  13 void native_set_fixmap(enum fixed_addresses idx,
  14                        unsigned long phys, pgprot_t flags);
  15
  16 #ifndef CONFIG_PARAVIRT
  17 static inline void __set_fixmap(enum fixed_addresses idx,
  18                                 unsigned long phys, pgprot_t flags)
  19 {
  20         native_set_fixmap(idx, phys, flags);
  21 }
  22 #endif
  23
  24 #define set_fixmap(idx, phys)                           \
  25         __set_fixmap(idx, phys, PAGE_KERNEL)
  26
  27 /*
  28  * Some hardware wants to get fixmapped without caching.
  29  */
  30 #define set_fixmap_nocache(idx, phys)                   \
  31         __set_fixmap(idx, phys, PAGE_KERNEL_NOCACHE)
  32
  33 #define clear_fixmap(idx)                       \
  34         __set_fixmap(idx, 0, __pgprot(0))
  35
  36 #define __fix_to_virt(x)        (FIXADDR_TOP - ((x) << PAGE_SHIFT))
  37 #define __virt_to_fix(x)        ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)
  38
  39 extern void __this_fixmap_does_not_exist(void);
  40
  41 /*
  42  * 'index to address' translation. If anyone tries to use the idx
  43  * directly without translation, we catch the bug with a NULL-deference
  44  * kernel oops. Illegal ranges of incoming indices are caught too.
  45  */
  46 static __always_inline unsigned long fix_to_virt(const unsigned int idx)
  47 {
  48         /*
  49          * this branch gets completely eliminated after inlining,
  50          * except when someone tries to use fixaddr indices in an
  51          * illegal way. (such as mixing up address types or using
  52          * out-of-range indices).
  53          *
  54          * If it doesn't get removed, the linker will complain
  55          * loudly with a reasonably clear error message..
  56          */
  57         if (idx >= __end_of_fixed_addresses)
  58                 __this_fixmap_does_not_exist();
  59
  60         return __fix_to_virt(idx);
  61 }
  62
  63 static inline unsigned long virt_to_fix(const unsigned long vaddr)
  64 {
  65         BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
  66         return __virt_to_fix(vaddr);
  67 }
  68 #endif