include/asm-generic/pgalloc.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef __ASM_GENERIC_PGALLOC_H
   3 #define __ASM_GENERIC_PGALLOC_H
   4
   5 #ifdef CONFIG_MMU
   6
   7 #define GFP_PGTABLE_KERNEL      (GFP_KERNEL | __GFP_ZERO)
   8 #define GFP_PGTABLE_USER        (GFP_PGTABLE_KERNEL | __GFP_ACCOUNT)
   9
  10 /**
  11  * __pte_alloc_one_kernel - allocate a page for PTE-level kernel page table
  12  * @mm: the mm_struct of the current context
  13  *
  14  * This function is intended for architectures that need
  15  * anything beyond simple page allocation.
  16  *
  17  * Return: pointer to the allocated memory or %NULL on error
  18  */
  19 static inline pte_t *__pte_alloc_one_kernel(struct mm_struct *mm)
  20 {
  21         return (pte_t *)__get_free_page(GFP_PGTABLE_KERNEL);
  22 }
  23
  24 #ifndef __HAVE_ARCH_PTE_ALLOC_ONE_KERNEL
  25 /**
  26  * pte_alloc_one_kernel - allocate a page for PTE-level kernel page table
  27  * @mm: the mm_struct of the current context
  28  *
  29  * Return: pointer to the allocated memory or %NULL on error
  30  */
  31 static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm)
  32 {
  33         return __pte_alloc_one_kernel(mm);
  34 }
  35 #endif
  36
  37 /**
  38  * pte_free_kernel - free PTE-level kernel page table page
  39  * @mm: the mm_struct of the current context
  40  * @pte: pointer to the memory containing the page table
  41  */
  42 static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
  43 {
  44         free_page((unsigned long)pte);
  45 }
  46
  47 /**
  48  * __pte_alloc_one - allocate a page for PTE-level user page table
  49  * @mm: the mm_struct of the current context
  50  * @gfp: GFP flags to use for the allocation
  51  *
  52  * Allocates a page and runs the pgtable_pte_page_ctor().
  53  *
  54  * This function is intended for architectures that need
  55  * anything beyond simple page allocation or must have custom GFP flags.
  56  *
  57  * Return: `struct page` initialized as page table or %NULL on error
  58  */
  59 static inline pgtable_t __pte_alloc_one(struct mm_struct *mm, gfp_t gfp)
  60 {
  61         struct page *pte;
  62
  63         pte = alloc_page(gfp);
  64         if (!pte)
  65                 return NULL;
  66         if (!pgtable_pte_page_ctor(pte)) {
  67                 __free_page(pte);
  68                 return NULL;
  69         }
  70
  71         return pte;
  72 }
  73
  74 #ifndef __HAVE_ARCH_PTE_ALLOC_ONE
  75 /**
  76  * pte_alloc_one - allocate a page for PTE-level user page table
  77  * @mm: the mm_struct of the current context
  78  *
  79  * Allocates a page and runs the pgtable_pte_page_ctor().
  80  *
  81  * Return: `struct page` initialized as page table or %NULL on error
  82  */
  83 static inline pgtable_t pte_alloc_one(struct mm_struct *mm)
  84 {
  85         return __pte_alloc_one(mm, GFP_PGTABLE_USER);
  86 }
  87 #endif
  88
  89 /*
  90  * Should really implement gc for free page table pages. This could be
  91  * done with a reference count in struct page.
  92  */
  93
  94 /**
  95  * pte_free - free PTE-level user page table page
  96  * @mm: the mm_struct of the current context
  97  * @pte_page: the `struct page` representing the page table
  98  */
  99 static inline void pte_free(struct mm_struct *mm, struct page *pte_page)
 100 {
 101         pgtable_pte_page_dtor(pte_page);
 102         __free_page(pte_page);
 103 }
 104
 105
 106 #if CONFIG_PGTABLE_LEVELS > 2
 107
 108 #ifndef __HAVE_ARCH_PMD_ALLOC_ONE
 109 /**
 110  * pmd_alloc_one - allocate a page for PMD-level page table
 111  * @mm: the mm_struct of the current context
 112  *
 113  * Allocates a page and runs the pgtable_pmd_page_ctor().
 114  * Allocations use %GFP_PGTABLE_USER in user context and
 115  * %GFP_PGTABLE_KERNEL in kernel context.
 116  *
 117  * Return: pointer to the allocated memory or %NULL on error
 118  */
 119 static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long addr)
 120 {
 121         struct page *page;
 122         gfp_t gfp = GFP_PGTABLE_USER;
 123
 124         if (mm == &init_mm)
 125                 gfp = GFP_PGTABLE_KERNEL;
 126         page = alloc_pages(gfp, 0);
 127         if (!page)
 128                 return NULL;
 129         if (!pgtable_pmd_page_ctor(page)) {
 130                 __free_pages(page, 0);
 131                 return NULL;
 132         }
 133         return (pmd_t *)page_address(page);
 134 }
 135 #endif
 136
 137 #ifndef __HAVE_ARCH_PMD_FREE
 138 static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
 139 {
 140         BUG_ON((unsigned long)pmd & (PAGE_SIZE-1));
 141         pgtable_pmd_page_dtor(virt_to_page(pmd));
 142         free_page((unsigned long)pmd);
 143 }
 144 #endif
 145
 146 #endif /* CONFIG_PGTABLE_LEVELS > 2 */
 147
 148 #if CONFIG_PGTABLE_LEVELS > 3
 149
 150 #ifndef __HAVE_ARCH_PUD_ALLOC_ONE
 151 /**
 152  * pud_alloc_one - allocate a page for PUD-level page table
 153  * @mm: the mm_struct of the current context
 154  *
 155  * Allocates a page using %GFP_PGTABLE_USER for user context and
 156  * %GFP_PGTABLE_KERNEL for kernel context.
 157  *
 158  * Return: pointer to the allocated memory or %NULL on error
 159  */
 160 static inline pud_t *pud_alloc_one(struct mm_struct *mm, unsigned long addr)
 161 {
 162         gfp_t gfp = GFP_PGTABLE_USER;
 163
 164         if (mm == &init_mm)
 165                 gfp = GFP_PGTABLE_KERNEL;
 166         return (pud_t *)get_zeroed_page(gfp);
 167 }
 168 #endif
 169
 170 static inline void pud_free(struct mm_struct *mm, pud_t *pud)
 171 {
 172         BUG_ON((unsigned long)pud & (PAGE_SIZE-1));
 173         free_page((unsigned long)pud);
 174 }
 175
 176 #endif /* CONFIG_PGTABLE_LEVELS > 3 */
 177
 178 #ifndef __HAVE_ARCH_PGD_FREE
 179 static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
 180 {
 181         free_page((unsigned long)pgd);
 182 }
 183 #endif
 184
 185 #endif /* CONFIG_MMU */
 186
 187 #endif /* __ASM_GENERIC_PGALLOC_H */