Linux kernel & device driver programming

Cross-Referenced Linux and Device Driver Code

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Version: [ 2.6.11.8 ] [ 2.6.25 ] [ 2.6.25.8 ] [ 2.6.31.13 ] Architecture: [ i386 ]
  1 #ifndef _ASM_X86_PGTABLE_2LEVEL_H
  2 #define _ASM_X86_PGTABLE_2LEVEL_H
  3 
  4 #define pte_ERROR(e) \
  5         printk("%s:%d: bad pte %08lx.\n", __FILE__, __LINE__, (e).pte_low)
  6 #define pgd_ERROR(e) \
  7         printk("%s:%d: bad pgd %08lx.\n", __FILE__, __LINE__, pgd_val(e))
  8 
  9 /*
 10  * Certain architectures need to do special things when PTEs
 11  * within a page table are directly modified.  Thus, the following
 12  * hook is made available.
 13  */
 14 static inline void native_set_pte(pte_t *ptep , pte_t pte)
 15 {
 16         *ptep = pte;
 17 }
 18 
 19 static inline void native_set_pmd(pmd_t *pmdp, pmd_t pmd)
 20 {
 21         *pmdp = pmd;
 22 }
 23 
 24 static inline void native_set_pte_atomic(pte_t *ptep, pte_t pte)
 25 {
 26         native_set_pte(ptep, pte);
 27 }
 28 
 29 static inline void native_pmd_clear(pmd_t *pmdp)
 30 {
 31         native_set_pmd(pmdp, __pmd(0));
 32 }
 33 
 34 static inline void native_pte_clear(struct mm_struct *mm,
 35                                     unsigned long addr, pte_t *xp)
 36 {
 37         *xp = native_make_pte(0);
 38 }
 39 
 40 #ifdef CONFIG_SMP
 41 static inline pte_t native_ptep_get_and_clear(pte_t *xp)
 42 {
 43         return __pte(xchg(&xp->pte_low, 0));
 44 }
 45 #else
 46 #define native_ptep_get_and_clear(xp) native_local_ptep_get_and_clear(xp)
 47 #endif
 48 
 49 /*
 50  * Bits _PAGE_BIT_PRESENT, _PAGE_BIT_FILE and _PAGE_BIT_PROTNONE are taken,
 51  * split up the 29 bits of offset into this range:
 52  */
 53 #define PTE_FILE_MAX_BITS       29
 54 #define PTE_FILE_SHIFT1         (_PAGE_BIT_PRESENT + 1)
 55 #if _PAGE_BIT_FILE < _PAGE_BIT_PROTNONE
 56 #define PTE_FILE_SHIFT2         (_PAGE_BIT_FILE + 1)
 57 #define PTE_FILE_SHIFT3         (_PAGE_BIT_PROTNONE + 1)
 58 #else
 59 #define PTE_FILE_SHIFT2         (_PAGE_BIT_PROTNONE + 1)
 60 #define PTE_FILE_SHIFT3         (_PAGE_BIT_FILE + 1)
 61 #endif
 62 #define PTE_FILE_BITS1          (PTE_FILE_SHIFT2 - PTE_FILE_SHIFT1 - 1)
 63 #define PTE_FILE_BITS2          (PTE_FILE_SHIFT3 - PTE_FILE_SHIFT2 - 1)
 64 
 65 #define pte_to_pgoff(pte)                                               \
 66         ((((pte).pte_low >> PTE_FILE_SHIFT1)                            \
 67           & ((1U << PTE_FILE_BITS1) - 1))                               \
 68          + ((((pte).pte_low >> PTE_FILE_SHIFT2)                         \
 69              & ((1U << PTE_FILE_BITS2) - 1)) << PTE_FILE_BITS1)         \
 70          + (((pte).pte_low >> PTE_FILE_SHIFT3)                          \
 71             << (PTE_FILE_BITS1 + PTE_FILE_BITS2)))
 72 
 73 #define pgoff_to_pte(off)                                               \
 74         ((pte_t) { .pte_low =                                           \
 75          (((off) & ((1U << PTE_FILE_BITS1) - 1)) << PTE_FILE_SHIFT1)    \
 76          + ((((off) >> PTE_FILE_BITS1) & ((1U << PTE_FILE_BITS2) - 1))  \
 77             << PTE_FILE_SHIFT2)                                         \
 78          + (((off) >> (PTE_FILE_BITS1 + PTE_FILE_BITS2))                \
 79             << PTE_FILE_SHIFT3)                                         \
 80          + _PAGE_FILE })
 81 
 82 /* Encode and de-code a swap entry */
 83 #if _PAGE_BIT_FILE < _PAGE_BIT_PROTNONE
 84 #define SWP_TYPE_BITS (_PAGE_BIT_FILE - _PAGE_BIT_PRESENT - 1)
 85 #define SWP_OFFSET_SHIFT (_PAGE_BIT_PROTNONE + 1)
 86 #else
 87 #define SWP_TYPE_BITS (_PAGE_BIT_PROTNONE - _PAGE_BIT_PRESENT - 1)
 88 #define SWP_OFFSET_SHIFT (_PAGE_BIT_FILE + 1)
 89 #endif
 90 
 91 #define MAX_SWAPFILES_CHECK() BUILD_BUG_ON(MAX_SWAPFILES_SHIFT > SWP_TYPE_BITS)
 92 
 93 #define __swp_type(x)                   (((x).val >> (_PAGE_BIT_PRESENT + 1)) \
 94                                          & ((1U << SWP_TYPE_BITS) - 1))
 95 #define __swp_offset(x)                 ((x).val >> SWP_OFFSET_SHIFT)
 96 #define __swp_entry(type, offset)       ((swp_entry_t) { \
 97                                          ((type) << (_PAGE_BIT_PRESENT + 1)) \
 98                                          | ((offset) << SWP_OFFSET_SHIFT) })
 99 #define __pte_to_swp_entry(pte)         ((swp_entry_t) { (pte).pte_low })
100 #define __swp_entry_to_pte(x)           ((pte_t) { .pte = (x).val })
101 
102 #endif /* _ASM_X86_PGTABLE_2LEVEL_H */
103 
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