LXR linux/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 */
  19static 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 */
  31static 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 */
  42static 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_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 */
  59static 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_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_page_ctor().
  80 *
  81 * Return: `struct page` initialized as page table or %NULL on error
  82 */
  83static 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 */
  99static inline void pte_free(struct mm_struct *mm, struct page *pte_page)
 100{
 101        pgtable_page_dtor(pte_page);
 102        __free_page(pte_page);
 103}
 104
 105#else /* CONFIG_MMU */
 106
 107/* This is enough for a nommu architecture */
 108#define check_pgt_cache()          do { } while (0)
 109
 110#endif /* CONFIG_MMU */
 111
 112#endif /* __ASM_GENERIC_PGALLOC_H */
 113