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 <asm/setup.h> 18 #include <asm/page.h> 19 #include <asm/pgtable-hwdef.h> 20 21 #include <linux/compiler.h> 22 23 /* 24 * We can convert va <=> pa page table addresses with simple casts 25 * because we always allocate their pages with alloc_page(), and 26 * alloc_page() always returns identity mapped pages. 27 */ 28 #define pgtable_va(x) ((void *)(unsigned long)(x)) 29 #define pgtable_pa(x) ((unsigned long)(x)) 30 31 #define pgd_none(pgd) (!pgd_val(pgd)) 32 #define pmd_none(pmd) (!pmd_val(pmd)) 33 #define pte_none(pte) (!pte_val(pte)) 34 35 #define pgd_index(addr) \ 36 (((addr) >> PGDIR_SHIFT) & (PTRS_PER_PGD - 1)) 37 #define pgd_offset(pgtable, addr) ((pgtable) + pgd_index(addr)) 38 39 #define pgd_free(pgd) free(pgd) 40 static inline pgd_t *pgd_alloc(void) 41 { 42 pgd_t *pgd = memalign(PAGE_SIZE, PTRS_PER_PGD * sizeof(pgd_t)); 43 memset(pgd, 0, PTRS_PER_PGD * sizeof(pgd_t)); 44 return pgd; 45 } 46 47 #define pmd_offset(pgd, addr) ((pmd_t *)pgd) 48 #define pmd_free(pmd) 49 #define pmd_alloc(pgd, addr) pmd_offset(pgd, addr) 50 51 static inline pte_t *pmd_page_vaddr(pmd_t pmd) 52 { 53 return pgtable_va(pmd_val(pmd) & PHYS_MASK & (s32)PAGE_MASK); 54 } 55 56 #define pte_index(addr) \ 57 (((addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1)) 58 #define pte_offset(pmd, addr) \ 59 (pmd_page_vaddr(*(pmd)) + pte_index(addr)) 60 61 #define pte_free(pte) free_page(pte) 62 static inline pte_t *pte_alloc_one(void) 63 { 64 assert(PTRS_PER_PTE * sizeof(pte_t) == PAGE_SIZE); 65 pte_t *pte = alloc_page(); 66 return pte; 67 } 68 static inline pte_t *pte_alloc(pmd_t *pmd, unsigned long addr) 69 { 70 if (pmd_none(*pmd)) { 71 pmd_t entry; 72 pmd_val(entry) = pgtable_pa(pte_alloc_one()) | PMD_TYPE_TABLE; 73 WRITE_ONCE(*pmd, entry); 74 } 75 return pte_offset(pmd, addr); 76 } 77 78 #endif /* _ASMARM64_PGTABLE_H_ */ 79