arch/parisc/include/asm/pgalloc.h

   1 #ifndef _ASM_PGALLOC_H
   2 #define _ASM_PGALLOC_H
   3
   4 #include <linux/gfp.h>
   5 #include <linux/mm.h>
   6 #include <linux/threads.h>
   7 #include <asm/processor.h>
   8 #include <asm/fixmap.h>
   9
  10 #include <asm/cache.h>
  11
  12 /* Allocate the top level pgd (page directory)
  13  *
  14  * Here (for 64 bit kernels) we implement a Hybrid L2/L3 scheme: we
  15  * allocate the first pmd adjacent to the pgd.  This means that we can
  16  * subtract a constant offset to get to it.  The pmd and pgd sizes are
  17  * arranged so that a single pmd covers 4GB (giving a full 64-bit
  18  * process access to 8TB) so our lookups are effectively L2 for the
  19  * first 4GB of the kernel (i.e. for all ILP32 processes and all the
  20  * kernel for machines with under 4GB of memory) */
  21 static inline pgd_t *pgd_alloc(struct mm_struct *mm)
  22 {
  23         pgd_t *pgd = (pgd_t *)__get_free_pages(GFP_KERNEL,
  24                                                PGD_ALLOC_ORDER);
  25         pgd_t *actual_pgd = pgd;
  26
  27         if (likely(pgd != NULL)) {
  28                 memset(pgd, 0, PAGE_SIZE<<PGD_ALLOC_ORDER);
  29 #if PT_NLEVELS == 3
  30                 actual_pgd += PTRS_PER_PGD;
  31                 /* Populate first pmd with allocated memory.  We mark it
  32                  * with PxD_FLAG_ATTACHED as a signal to the system that this
  33                  * pmd entry may not be cleared. */
  34                 __pgd_val_set(*actual_pgd, (PxD_FLAG_PRESENT |
  35                                         PxD_FLAG_VALID |
  36                                         PxD_FLAG_ATTACHED)
  37                         + (__u32)(__pa((unsigned long)pgd) >> PxD_VALUE_SHIFT));
  38                 /* The first pmd entry also is marked with _PAGE_GATEWAY as
  39                  * a signal that this pmd may not be freed */
  40                 __pgd_val_set(*pgd, PxD_FLAG_ATTACHED);
  41 #endif
  42         }
  43         return actual_pgd;
  44 }
  45
  46 static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
  47 {
  48 #if PT_NLEVELS == 3
  49         pgd -= PTRS_PER_PGD;
  50 #endif
  51         free_pages((unsigned long)pgd, PGD_ALLOC_ORDER);
  52 }
  53
  54 #if PT_NLEVELS == 3
  55
  56 /* Three Level Page Table Support for pmd's */
  57
  58 static inline void pgd_populate(struct mm_struct *mm, pgd_t *pgd, pmd_t *pmd)
  59 {
  60         __pgd_val_set(*pgd, (PxD_FLAG_PRESENT | PxD_FLAG_VALID) +
  61                         (__u32)(__pa((unsigned long)pmd) >> PxD_VALUE_SHIFT));
  62 }
  63
  64 static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long address)
  65 {
  66         pmd_t *pmd = (pmd_t *)__get_free_pages(GFP_KERNEL|__GFP_REPEAT,
  67                                                PMD_ORDER);
  68         if (pmd)
  69                 memset(pmd, 0, PAGE_SIZE<<PMD_ORDER);
  70         return pmd;
  71 }
  72
  73 static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
  74 {
  75         if(pmd_flag(*pmd) & PxD_FLAG_ATTACHED)
  76                 /*
  77                  * This is the permanent pmd attached to the pgd;
  78                  * cannot free it.
  79                  * Increment the counter to compensate for the decrement
  80                  * done by generic mm code.
  81                  */
  82                 mm_inc_nr_pmds(mm);
  83                 return;
  84         free_pages((unsigned long)pmd, PMD_ORDER);
  85 }
  86
  87 #else
  88
  89 /* Two Level Page Table Support for pmd's */
  90
  91 /*
  92  * allocating and freeing a pmd is trivial: the 1-entry pmd is
  93  * inside the pgd, so has no extra memory associated with it.
  94  */
  95
  96 #define pmd_alloc_one(mm, addr)         ({ BUG(); ((pmd_t *)2); })
  97 #define pmd_free(mm, x)                 do { } while (0)
  98 #define pgd_populate(mm, pmd, pte)      BUG()
  99
 100 #endif
 101
 102 static inline void
 103 pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd, pte_t *pte)
 104 {
 105 #if PT_NLEVELS == 3
 106         /* preserve the gateway marker if this is the beginning of
 107          * the permanent pmd */
 108         if(pmd_flag(*pmd) & PxD_FLAG_ATTACHED)
 109                 __pmd_val_set(*pmd, (PxD_FLAG_PRESENT |
 110                                  PxD_FLAG_VALID |
 111                                  PxD_FLAG_ATTACHED)
 112                         + (__u32)(__pa((unsigned long)pte) >> PxD_VALUE_SHIFT));
 113         else
 114 #endif
 115                 __pmd_val_set(*pmd, (PxD_FLAG_PRESENT | PxD_FLAG_VALID)
 116                         + (__u32)(__pa((unsigned long)pte) >> PxD_VALUE_SHIFT));
 117 }
 118
 119 #define pmd_populate(mm, pmd, pte_page) \
 120         pmd_populate_kernel(mm, pmd, page_address(pte_page))
 121 #define pmd_pgtable(pmd) pmd_page(pmd)
 122
 123 static inline pgtable_t
 124 pte_alloc_one(struct mm_struct *mm, unsigned long address)
 125 {
 126         struct page *page = alloc_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
 127         if (!page)
 128                 return NULL;
 129         if (!pgtable_page_ctor(page)) {
 130                 __free_page(page);
 131                 return NULL;
 132         }
 133         return page;
 134 }
 135
 136 static inline pte_t *
 137 pte_alloc_one_kernel(struct mm_struct *mm, unsigned long addr)
 138 {
 139         pte_t *pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
 140         return pte;
 141 }
 142
 143 static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
 144 {
 145         free_page((unsigned long)pte);
 146 }
 147
 148 static inline void pte_free(struct mm_struct *mm, struct page *pte)
 149 {
 150         pgtable_page_dtor(pte);
 151         pte_free_kernel(mm, page_address(pte));
 152 }
 153
 154 #define check_pgt_cache()       do { } while (0)
 155
 156 #endif