include/asm-parisc/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/pgtable.h>
  11 #include <asm/cache.h>
  12
  13 /* Allocate the top level pgd (page directory)
  14  *
  15  * Here (for 64 bit kernels) we implement a Hybrid L2/L3 scheme: we
  16  * allocate the first pmd adjacent to the pgd.  This means that we can
  17  * subtract a constant offset to get to it.  The pmd and pgd sizes are
  18  * arranged so that a single pmd covers 4GB (giving a full LP64
  19  * process access to 8TB) so our lookups are effectively L2 for the
  20  * first 4GB of the kernel (i.e. for all ILP32 processes and all the
  21  * kernel for machines with under 4GB of memory) */
  22 static inline pgd_t *pgd_alloc(struct mm_struct *mm)
  23 {
  24         pgd_t *pgd = (pgd_t *)__get_free_pages(GFP_KERNEL,
  25                                                PGD_ALLOC_ORDER);
  26         pgd_t *actual_pgd = pgd;
  27
  28         if (likely(pgd != NULL)) {
  29                 memset(pgd, 0, PAGE_SIZE<<PGD_ALLOC_ORDER);
  30 #ifdef __LP64__
  31                 actual_pgd += PTRS_PER_PGD;
  32                 /* Populate first pmd with allocated memory.  We mark it
  33                  * with PxD_FLAG_ATTACHED as a signal to the system that this
  34                  * pmd entry may not be cleared. */
  35                 __pgd_val_set(*actual_pgd, (PxD_FLAG_PRESENT |
  36                                         PxD_FLAG_VALID |
  37                                         PxD_FLAG_ATTACHED)
  38                         + (__u32)(__pa((unsigned long)pgd) >> PxD_VALUE_SHIFT));
  39                 /* The first pmd entry also is marked with _PAGE_GATEWAY as
  40                  * a signal that this pmd may not be freed */
  41                 __pgd_val_set(*pgd, PxD_FLAG_ATTACHED);
  42 #endif
  43         }
  44         return actual_pgd;
  45 }
  46
  47 static inline void pgd_free(pgd_t *pgd)
  48 {
  49 #ifdef __LP64__
  50         pgd -= PTRS_PER_PGD;
  51 #endif
  52         free_pages((unsigned long)pgd, PGD_ALLOC_ORDER);
  53 }
  54
  55 #if PT_NLEVELS == 3
  56
  57 /* Three Level Page Table Support for pmd's */
  58
  59 static inline void pgd_populate(struct mm_struct *mm, pgd_t *pgd, pmd_t *pmd)
  60 {
  61         __pgd_val_set(*pgd, (PxD_FLAG_PRESENT | PxD_FLAG_VALID) +
  62                         (__u32)(__pa((unsigned long)pmd) >> PxD_VALUE_SHIFT));
  63 }
  64
  65 static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long address)
  66 {
  67         pmd_t *pmd = (pmd_t *)__get_free_pages(GFP_KERNEL|__GFP_REPEAT,
  68                                                PMD_ORDER);
  69         if (pmd)
  70                 memset(pmd, 0, PAGE_SIZE<<PMD_ORDER);
  71         return pmd;
  72 }
  73
  74 static inline void pmd_free(pmd_t *pmd)
  75 {
  76 #ifdef __LP64__
  77         if(pmd_flag(*pmd) & PxD_FLAG_ATTACHED)
  78                 /* This is the permanent pmd attached to the pgd;
  79                  * cannot free it */
  80                 return;
  81 #endif
  82         free_pages((unsigned long)pmd, PMD_ORDER);
  83 }
  84
  85 #else
  86
  87 /* Two Level Page Table Support for pmd's */
  88
  89 /*
  90  * allocating and freeing a pmd is trivial: the 1-entry pmd is
  91  * inside the pgd, so has no extra memory associated with it.
  92  */
  93
  94 #define pmd_alloc_one(mm, addr)         ({ BUG(); ((pmd_t *)2); })
  95 #define pmd_free(x)                     do { } while (0)
  96 #define pgd_populate(mm, pmd, pte)      BUG()
  97
  98 #endif
  99
 100 static inline void
 101 pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd, pte_t *pte)
 102 {
 103 #ifdef __LP64__
 104         /* preserve the gateway marker if this is the beginning of
 105          * the permanent pmd */
 106         if(pmd_flag(*pmd) & PxD_FLAG_ATTACHED)
 107                 __pmd_val_set(*pmd, (PxD_FLAG_PRESENT |
 108                                  PxD_FLAG_VALID |
 109                                  PxD_FLAG_ATTACHED)
 110                         + (__u32)(__pa((unsigned long)pte) >> PxD_VALUE_SHIFT));
 111         else
 112 #endif
 113                 __pmd_val_set(*pmd, (PxD_FLAG_PRESENT | PxD_FLAG_VALID)
 114                         + (__u32)(__pa((unsigned long)pte) >> PxD_VALUE_SHIFT));
 115 }
 116
 117 #define pmd_populate(mm, pmd, pte_page) \
 118         pmd_populate_kernel(mm, pmd, page_address(pte_page))
 119
 120 static inline struct page *
 121 pte_alloc_one(struct mm_struct *mm, unsigned long address)
 122 {
 123         struct page *page = alloc_page(GFP_KERNEL|__GFP_REPEAT);
 124         if (likely(page != NULL))
 125                 clear_page(page_address(page));
 126         return page;
 127 }
 128
 129 static inline pte_t *
 130 pte_alloc_one_kernel(struct mm_struct *mm, unsigned long addr)
 131 {
 132         pte_t *pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT);
 133         if (likely(pte != NULL))
 134                 clear_page(pte);
 135         return pte;
 136 }
 137
 138 static inline void pte_free_kernel(pte_t *pte)
 139 {
 140         free_page((unsigned long)pte);
 141 }
 142
 143 #define pte_free(page)  pte_free_kernel(page_address(page))
 144
 145 extern int do_check_pgt_cache(int, int);
 146 #define check_pgt_cache()       do { } while (0)
 147
 148 #endif