6 #include <linux/threads.h>
7 #include <asm/processor.h>
8 #include <asm/fixmap.h>
10 #include <asm/cache.h>
12 /* Allocate the top level pgd (page directory)
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 LP64
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)
23 pgd_t *pgd = (pgd_t *)__get_free_pages(GFP_KERNEL,
25 pgd_t *actual_pgd = pgd;
27 if (likely(pgd != NULL)) {
28 memset(pgd, 0, PAGE_SIZE<<PGD_ALLOC_ORDER);
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 |
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);
46 static inline void pgd_free(pgd_t *pgd)
51 free_pages((unsigned long)pgd, PGD_ALLOC_ORDER);
56 /* Three Level Page Table Support for pmd's */
58 static inline void pgd_populate(struct mm_struct *mm, pgd_t *pgd, pmd_t *pmd)
60 __pgd_val_set(*pgd, (PxD_FLAG_PRESENT | PxD_FLAG_VALID) +
61 (__u32)(__pa((unsigned long)pmd) >> PxD_VALUE_SHIFT));
64 static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long address)
66 pmd_t *pmd = (pmd_t *)__get_free_pages(GFP_KERNEL|__GFP_REPEAT,
69 memset(pmd, 0, PAGE_SIZE<<PMD_ORDER);
73 static inline void pmd_free(pmd_t *pmd)
76 if(pmd_flag(*pmd) & PxD_FLAG_ATTACHED)
77 /* This is the permanent pmd attached to the pgd;
81 free_pages((unsigned long)pmd, PMD_ORDER);
86 /* Two Level Page Table Support for pmd's */
89 * allocating and freeing a pmd is trivial: the 1-entry pmd is
90 * inside the pgd, so has no extra memory associated with it.
93 #define pmd_alloc_one(mm, addr) ({ BUG(); ((pmd_t *)2); })
94 #define pmd_free(x) do { } while (0)
95 #define pgd_populate(mm, pmd, pte) BUG()
100 pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd, pte_t *pte)
103 /* preserve the gateway marker if this is the beginning of
104 * the permanent pmd */
105 if(pmd_flag(*pmd) & PxD_FLAG_ATTACHED)
106 __pmd_val_set(*pmd, (PxD_FLAG_PRESENT |
109 + (__u32)(__pa((unsigned long)pte) >> PxD_VALUE_SHIFT));
112 __pmd_val_set(*pmd, (PxD_FLAG_PRESENT | PxD_FLAG_VALID)
113 + (__u32)(__pa((unsigned long)pte) >> PxD_VALUE_SHIFT));
116 #define pmd_populate(mm, pmd, pte_page) \
117 pmd_populate_kernel(mm, pmd, page_address(pte_page))
119 static inline struct page *
120 pte_alloc_one(struct mm_struct *mm, unsigned long address)
122 struct page *page = alloc_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
126 static inline pte_t *
127 pte_alloc_one_kernel(struct mm_struct *mm, unsigned long addr)
129 pte_t *pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
133 static inline void pte_free_kernel(pte_t *pte)
135 free_page((unsigned long)pte);
138 #define pte_free(page) pte_free_kernel(page_address(page))
140 #define check_pgt_cache() do { } while (0)