1 #ifndef _ASMARM64_PGTABLE_H_ 2 #define _ASMARM64_PGTABLE_H_ 3 /* 4 * Adapted from arch/arm64/include/asm/pgtable.h 5 * include/asm-generic/pgtable-nopmd.h 6 * include/linux/mm.h 7 * 8 * Note: some Linux function APIs have been modified. Nothing crazy, 9 * but if a function took, for example, an mm_struct, then 10 * that was either removed or replaced. 11 * 12 * Copyright (C) 2017, Red Hat Inc, Andrew Jones <drjones@redhat.com> 13 * 14 * This work is licensed under the terms of the GNU GPL, version 2. 15 */ 16 #include <alloc.h> 17 #include <alloc_page.h> 18 #include <asm/setup.h> 19 #include <asm/page.h> 20 #include <asm/pgtable-hwdef.h> 21 22 #include <linux/compiler.h> 23 24 /* 25 * We can convert va <=> pa page table addresses with simple casts 26 * because we always allocate their pages with alloc_page(), and 27 * alloc_page() always returns identity mapped pages. 28 */ 29 #define pgtable_va(x) ((void *)(unsigned long)(x)) 30 #define pgtable_pa(x) ((unsigned long)(x)) 31 32 #define pgd_none(pgd) (!pgd_val(pgd)) 33 #define pmd_none(pmd) (!pmd_val(pmd)) 34 #define pte_none(pte) (!pte_val(pte)) 35 36 #define pgd_index(addr) \ 37 (((addr) >> PGDIR_SHIFT) & (PTRS_PER_PGD - 1)) 38 #define pgd_offset(pgtable, addr) ((pgtable) + pgd_index(addr)) 39 40 #define pgd_free(pgd) free(pgd) 41 static inline pgd_t *pgd_alloc(void) 42 { 43 pgd_t *pgd = memalign(PAGE_SIZE, PTRS_PER_PGD * sizeof(pgd_t)); 44 memset(pgd, 0, PTRS_PER_PGD * sizeof(pgd_t)); 45 return pgd; 46 } 47 48 #define pmd_offset(pgd, addr) ((pmd_t *)pgd) 49 #define pmd_free(pmd) 50 #define pmd_alloc(pgd, addr) pmd_offset(pgd, addr) 51 52 static inline pte_t *pmd_page_vaddr(pmd_t pmd) 53 { 54 return pgtable_va(pmd_val(pmd) & PHYS_MASK & (s32)PAGE_MASK); 55 } 56 57 #define pte_index(addr) \ 58 (((addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1)) 59 #define pte_offset(pmd, addr) \ 60 (pmd_page_vaddr(*(pmd)) + pte_index(addr)) 61 62 #define pte_free(pte) free_page(pte) 63 static inline pte_t *pte_alloc_one(void) 64 { 65 assert(PTRS_PER_PTE * sizeof(pte_t) == PAGE_SIZE); 66 pte_t *pte = alloc_page(); 67 return pte; 68 } 69 static inline pte_t *pte_alloc(pmd_t *pmd, unsigned long addr) 70 { 71 if (pmd_none(*pmd)) { 72 pmd_t entry; 73 pmd_val(entry) = pgtable_pa(pte_alloc_one()) | PMD_TYPE_TABLE; 74 WRITE_ONCE(*pmd, entry); 75 } 76 return pte_offset(pmd, addr); 77 } 78 79 #endif /* _ASMARM64_PGTABLE_H_ */ 80