arch/x86/include/asm/fixmap.h

   1 #ifndef _ASM_X86_FIXMAP_H
   2 #define _ASM_X86_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 extern pte_t *kmap_pte;
  13 extern pgprot_t kmap_prot;
  14 extern pte_t *pkmap_page_table;
  15
  16 void __native_set_fixmap(enum fixed_addresses idx, pte_t pte);
  17 void native_set_fixmap(enum fixed_addresses idx,
  18                        unsigned long phys, pgprot_t flags);
  19
  20 #ifndef CONFIG_PARAVIRT
  21 static inline void __set_fixmap(enum fixed_addresses idx,
  22                                 unsigned long phys, pgprot_t flags)
  23 {
  24         native_set_fixmap(idx, phys, flags);
  25 }
  26 #endif
  27
  28 #define set_fixmap(idx, phys)                           \
  29         __set_fixmap(idx, phys, PAGE_KERNEL)
  30
  31 /*
  32  * Some hardware wants to get fixmapped without caching.
  33  */
  34 #define set_fixmap_nocache(idx, phys)                   \
  35         __set_fixmap(idx, phys, PAGE_KERNEL_NOCACHE)
  36
  37 #define clear_fixmap(idx)                       \
  38         __set_fixmap(idx, 0, __pgprot(0))
  39
  40 #define __fix_to_virt(x)        (FIXADDR_TOP - ((x) << PAGE_SHIFT))
  41 #define __virt_to_fix(x)        ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)
  42
  43 extern void __this_fixmap_does_not_exist(void);
  44
  45 /*
  46  * 'index to address' translation. If anyone tries to use the idx
  47  * directly without translation, we catch the bug with a NULL-deference
  48  * kernel oops. Illegal ranges of incoming indices are caught too.
  49  */
  50 static __always_inline unsigned long fix_to_virt(const unsigned int idx)
  51 {
  52         /*
  53          * this branch gets completely eliminated after inlining,
  54          * except when someone tries to use fixaddr indices in an
  55          * illegal way. (such as mixing up address types or using
  56          * out-of-range indices).
  57          *
  58          * If it doesn't get removed, the linker will complain
  59          * loudly with a reasonably clear error message..
  60          */
  61         if (idx >= __end_of_fixed_addresses)
  62                 __this_fixmap_does_not_exist();
  63
  64         return __fix_to_virt(idx);
  65 }
  66
  67 static inline unsigned long virt_to_fix(const unsigned long vaddr)
  68 {
  69         BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
  70         return __virt_to_fix(vaddr);
  71 }
  72 #endif /* _ASM_X86_FIXMAP_H */