arch/arm/include/asm/pgalloc.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  *  arch/arm/include/asm/pgalloc.h
   4  *
   5  *  Copyright (C) 2000-2001 Russell King
   6  */
   7 #ifndef _ASMARM_PGALLOC_H
   8 #define _ASMARM_PGALLOC_H
   9
  10 #include <linux/pagemap.h>
  11
  12 #include <asm/domain.h>
  13 #include <asm/pgtable-hwdef.h>
  14 #include <asm/processor.h>
  15 #include <asm/cacheflush.h>
  16 #include <asm/tlbflush.h>
  17
  18 #ifdef CONFIG_MMU
  19
  20 #define _PAGE_USER_TABLE        (PMD_TYPE_TABLE | PMD_BIT4 | PMD_DOMAIN(DOMAIN_USER))
  21 #define _PAGE_KERNEL_TABLE      (PMD_TYPE_TABLE | PMD_BIT4 | PMD_DOMAIN(DOMAIN_KERNEL))
  22
  23 #ifdef CONFIG_ARM_LPAE
  24
  25 static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long addr)
  26 {
  27         return (pmd_t *)get_zeroed_page(GFP_KERNEL);
  28 }
  29
  30 static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
  31 {
  32         BUG_ON((unsigned long)pmd & (PAGE_SIZE-1));
  33         free_page((unsigned long)pmd);
  34 }
  35
  36 static inline void pud_populate(struct mm_struct *mm, pud_t *pud, pmd_t *pmd)
  37 {
  38         set_pud(pud, __pud(__pa(pmd) | PMD_TYPE_TABLE));
  39 }
  40
  41 #else   /* !CONFIG_ARM_LPAE */
  42
  43 /*
  44  * Since we have only two-level page tables, these are trivial
  45  */
  46 #define pmd_alloc_one(mm,addr)          ({ BUG(); ((pmd_t *)2); })
  47 #define pmd_free(mm, pmd)               do { } while (0)
  48 #define pud_populate(mm,pmd,pte)        BUG()
  49
  50 #endif  /* CONFIG_ARM_LPAE */
  51
  52 extern pgd_t *pgd_alloc(struct mm_struct *mm);
  53 extern void pgd_free(struct mm_struct *mm, pgd_t *pgd);
  54
  55 static inline void clean_pte_table(pte_t *pte)
  56 {
  57         clean_dcache_area(pte + PTE_HWTABLE_PTRS, PTE_HWTABLE_SIZE);
  58 }
  59
  60 /*
  61  * Allocate one PTE table.
  62  *
  63  * This actually allocates two hardware PTE tables, but we wrap this up
  64  * into one table thus:
  65  *
  66  *  +------------+
  67  *  | Linux pt 0 |
  68  *  +------------+
  69  *  | Linux pt 1 |
  70  *  +------------+
  71  *  |  h/w pt 0  |
  72  *  +------------+
  73  *  |  h/w pt 1  |
  74  *  +------------+
  75  */
  76
  77 #define __HAVE_ARCH_PTE_ALLOC_ONE_KERNEL
  78 #define __HAVE_ARCH_PTE_ALLOC_ONE
  79 #include <asm-generic/pgalloc.h>
  80
  81 static inline pte_t *
  82 pte_alloc_one_kernel(struct mm_struct *mm)
  83 {
  84         pte_t *pte = __pte_alloc_one_kernel(mm);
  85
  86         if (pte)
  87                 clean_pte_table(pte);
  88
  89         return pte;
  90 }
  91
  92 #ifdef CONFIG_HIGHPTE
  93 #define PGTABLE_HIGHMEM __GFP_HIGHMEM
  94 #else
  95 #define PGTABLE_HIGHMEM 0
  96 #endif
  97
  98 static inline pgtable_t
  99 pte_alloc_one(struct mm_struct *mm)
 100 {
 101         struct page *pte;
 102
 103         pte = __pte_alloc_one(mm, GFP_PGTABLE_USER | PGTABLE_HIGHMEM);
 104         if (!pte)
 105                 return NULL;
 106         if (!PageHighMem(pte))
 107                 clean_pte_table(page_address(pte));
 108         return pte;
 109 }
 110
 111 static inline void __pmd_populate(pmd_t *pmdp, phys_addr_t pte,
 112                                   pmdval_t prot)
 113 {
 114         pmdval_t pmdval = (pte + PTE_HWTABLE_OFF) | prot;
 115         pmdp[0] = __pmd(pmdval);
 116 #ifndef CONFIG_ARM_LPAE
 117         pmdp[1] = __pmd(pmdval + 256 * sizeof(pte_t));
 118 #endif
 119         flush_pmd_entry(pmdp);
 120 }
 121
 122 /*
 123  * Populate the pmdp entry with a pointer to the pte.  This pmd is part
 124  * of the mm address space.
 125  *
 126  * Ensure that we always set both PMD entries.
 127  */
 128 static inline void
 129 pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmdp, pte_t *ptep)
 130 {
 131         /*
 132          * The pmd must be loaded with the physical address of the PTE table
 133          */
 134         __pmd_populate(pmdp, __pa(ptep), _PAGE_KERNEL_TABLE);
 135 }
 136
 137 static inline void
 138 pmd_populate(struct mm_struct *mm, pmd_t *pmdp, pgtable_t ptep)
 139 {
 140         extern pmdval_t user_pmd_table;
 141         pmdval_t prot;
 142
 143         if (__LINUX_ARM_ARCH__ >= 6 && !IS_ENABLED(CONFIG_ARM_LPAE))
 144                 prot = user_pmd_table;
 145         else
 146                 prot = _PAGE_USER_TABLE;
 147
 148         __pmd_populate(pmdp, page_to_phys(ptep), prot);
 149 }
 150 #define pmd_pgtable(pmd) pmd_page(pmd)
 151
 152 #endif /* CONFIG_MMU */
 153
 154 #endif