arch/x86/include/asm/pgtable-3level.h

   1 #ifndef _ASM_X86_PGTABLE_3LEVEL_H
   2 #define _ASM_X86_PGTABLE_3LEVEL_H
   3
   4 /*
   5  * Intel Physical Address Extension (PAE) Mode - three-level page
   6  * tables on PPro+ CPUs.
   7  *
   8  * Copyright (C) 1999 Ingo Molnar <mingo@redhat.com>
   9  */
  10
  11 #define pte_ERROR(e)                                                    \
  12         printk("%s:%d: bad pte %p(%08lx%08lx).\n",                      \
  13                __FILE__, __LINE__, &(e), (e).pte_high, (e).pte_low)
  14 #define pmd_ERROR(e)                                                    \
  15         printk("%s:%d: bad pmd %p(%016Lx).\n",                          \
  16                __FILE__, __LINE__, &(e), pmd_val(e))
  17 #define pgd_ERROR(e)                                                    \
  18         printk("%s:%d: bad pgd %p(%016Lx).\n",                          \
  19                __FILE__, __LINE__, &(e), pgd_val(e))
  20
  21 static inline int pud_none(pud_t pud)
  22 {
  23         return pud_val(pud) == 0;
  24 }
  25
  26 static inline int pud_bad(pud_t pud)
  27 {
  28         return (pud_val(pud) & ~(PTE_PFN_MASK | _KERNPG_TABLE | _PAGE_USER)) != 0;
  29 }
  30
  31 static inline int pud_present(pud_t pud)
  32 {
  33         return pud_val(pud) & _PAGE_PRESENT;
  34 }
  35
  36 /* Rules for using set_pte: the pte being assigned *must* be
  37  * either not present or in a state where the hardware will
  38  * not attempt to update the pte.  In places where this is
  39  * not possible, use pte_get_and_clear to obtain the old pte
  40  * value and then use set_pte to update it.  -ben
  41  */
  42 static inline void native_set_pte(pte_t *ptep, pte_t pte)
  43 {
  44         ptep->pte_high = pte.pte_high;
  45         smp_wmb();
  46         ptep->pte_low = pte.pte_low;
  47 }
  48
  49 /*
  50  * Since this is only called on user PTEs, and the page fault handler
  51  * must handle the already racy situation of simultaneous page faults,
  52  * we are justified in merely clearing the PTE present bit, followed
  53  * by a set.  The ordering here is important.
  54  */
  55 static inline void native_set_pte_present(struct mm_struct *mm,
  56                                           unsigned long addr,
  57                                           pte_t *ptep, pte_t pte)
  58 {
  59         ptep->pte_low = 0;
  60         smp_wmb();
  61         ptep->pte_high = pte.pte_high;
  62         smp_wmb();
  63         ptep->pte_low = pte.pte_low;
  64 }
  65
  66 static inline void native_set_pte_atomic(pte_t *ptep, pte_t pte)
  67 {
  68         set_64bit((unsigned long long *)(ptep), native_pte_val(pte));
  69 }
  70
  71 static inline void native_set_pmd(pmd_t *pmdp, pmd_t pmd)
  72 {
  73         set_64bit((unsigned long long *)(pmdp), native_pmd_val(pmd));
  74 }
  75
  76 static inline void native_set_pud(pud_t *pudp, pud_t pud)
  77 {
  78         set_64bit((unsigned long long *)(pudp), native_pud_val(pud));
  79 }
  80
  81 /*
  82  * For PTEs and PDEs, we must clear the P-bit first when clearing a page table
  83  * entry, so clear the bottom half first and enforce ordering with a compiler
  84  * barrier.
  85  */
  86 static inline void native_pte_clear(struct mm_struct *mm, unsigned long addr,
  87                                     pte_t *ptep)
  88 {
  89         ptep->pte_low = 0;
  90         smp_wmb();
  91         ptep->pte_high = 0;
  92 }
  93
  94 static inline void native_pmd_clear(pmd_t *pmd)
  95 {
  96         u32 *tmp = (u32 *)pmd;
  97         *tmp = 0;
  98         smp_wmb();
  99         *(tmp + 1) = 0;
 100 }
 101
 102 static inline void pud_clear(pud_t *pudp)
 103 {
 104         unsigned long pgd;
 105
 106         set_pud(pudp, __pud(0));
 107
 108         /*
 109          * According to Intel App note "TLBs, Paging-Structure Caches,
 110          * and Their Invalidation", April 2007, document 317080-001,
 111          * section 8.1: in PAE mode we explicitly have to flush the
 112          * TLB via cr3 if the top-level pgd is changed...
 113          *
 114          * Make sure the pud entry we're updating is within the
 115          * current pgd to avoid unnecessary TLB flushes.
 116          */
 117         pgd = read_cr3();
 118         if (__pa(pudp) >= pgd && __pa(pudp) <
 119             (pgd + sizeof(pgd_t)*PTRS_PER_PGD))
 120                 write_cr3(pgd);
 121 }
 122
 123 #define pud_page(pud) pfn_to_page(pud_val(pud) >> PAGE_SHIFT)
 124
 125 #define pud_page_vaddr(pud) ((unsigned long) __va(pud_val(pud) & PTE_PFN_MASK))
 126
 127
 128 /* Find an entry in the second-level page table.. */
 129 #define pmd_offset(pud, address) ((pmd_t *)pud_page_vaddr(*(pud)) +     \
 130                                   pmd_index(address))
 131
 132 #ifdef CONFIG_SMP
 133 static inline pte_t native_ptep_get_and_clear(pte_t *ptep)
 134 {
 135         pte_t res;
 136
 137         /* xchg acts as a barrier before the setting of the high bits */
 138         res.pte_low = xchg(&ptep->pte_low, 0);
 139         res.pte_high = ptep->pte_high;
 140         ptep->pte_high = 0;
 141
 142         return res;
 143 }
 144 #else
 145 #define native_ptep_get_and_clear(xp) native_local_ptep_get_and_clear(xp)
 146 #endif
 147
 148 #define __HAVE_ARCH_PTE_SAME
 149 static inline int pte_same(pte_t a, pte_t b)
 150 {
 151         return a.pte_low == b.pte_low && a.pte_high == b.pte_high;
 152 }
 153
 154 /*
 155  * Bits 0, 6 and 7 are taken in the low part of the pte,
 156  * put the 32 bits of offset into the high part.
 157  */
 158 #define pte_to_pgoff(pte) ((pte).pte_high)
 159 #define pgoff_to_pte(off)                                               \
 160         ((pte_t) { { .pte_low = _PAGE_FILE, .pte_high = (off) } })
 161 #define PTE_FILE_MAX_BITS       32
 162
 163 /* Encode and de-code a swap entry */
 164 #define MAX_SWAPFILES_CHECK() BUILD_BUG_ON(MAX_SWAPFILES_SHIFT > 5)
 165 #define __swp_type(x)                   (((x).val) & 0x1f)
 166 #define __swp_offset(x)                 ((x).val >> 5)
 167 #define __swp_entry(type, offset)       ((swp_entry_t){(type) | (offset) << 5})
 168 #define __pte_to_swp_entry(pte)         ((swp_entry_t){ (pte).pte_high })
 169 #define __swp_entry_to_pte(x)           ((pte_t){ { .pte_high = (x).val } })
 170
 171 #endif /* _ASM_X86_PGTABLE_3LEVEL_H */