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) */ 21static 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#ifdef CONFIG_64BIT 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 46static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd) 47{ 48#ifdef CONFIG_64BIT 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 58static 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 64static 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 73static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd) 74{ 75#ifdef CONFIG_64BIT 76 if(pmd_flag(*pmd) & PxD_FLAG_ATTACHED) 77 /* This is the permanent pmd attached to the pgd; 78 * cannot free it */ 79 return; 80#endif 81 free_pages((unsigned long)pmd, PMD_ORDER); 82} 83 84#else 85 86/* Two Level Page Table Support for pmd's */ 87 88/* 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. 91 */ 92 93#define pmd_alloc_one(mm, addr) ({ BUG(); ((pmd_t *)2); }) 94#define pmd_free(mm, x) do { } while (0) 95#define pgd_populate(mm, pmd, pte) BUG() 96 97#endif 98 99static inline void 100pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd, pte_t *pte) 101{ 102#ifdef CONFIG_64BIT 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 | 107 PxD_FLAG_VALID | 108 PxD_FLAG_ATTACHED) 109 + (__u32)(__pa((unsigned long)pte) >> PxD_VALUE_SHIFT)); 110 else 111#endif 112 __pmd_val_set(*pmd, (PxD_FLAG_PRESENT | PxD_FLAG_VALID) 113 + (__u32)(__pa((unsigned long)pte) >> PxD_VALUE_SHIFT)); 114} 115 116#define pmd_populate(mm, pmd, pte_page) \ 117 pmd_populate_kernel(mm, pmd, page_address(pte_page)) 118#define pmd_pgtable(pmd) pmd_page(pmd) 119 120static inline pgtable_t 121pte_alloc_one(struct mm_struct *mm, unsigned long address) 122{ 123 struct page *page = alloc_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO); 124 if (page) 125 pgtable_page_ctor(page); 126 return page; 127} 128 129static inline pte_t * 130pte_alloc_one_kernel(struct mm_struct *mm, unsigned long addr) 131{ 132 pte_t *pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO); 133 return pte; 134} 135 136static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte) 137{ 138 free_page((unsigned long)pte); 139} 140 141static inline void pte_free(struct mm_struct *mm, struct page *pte) 142{ 143 pgtable_page_dtor(pte); 144 pte_free_kernel(mm, page_address(pte)); 145} 146 147#define check_pgt_cache() do { } while (0) 148 149#endif 150