1 /* SPDX-License-Identifier: GPL-2.0-only */ 2 /* 3 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) 4 * 5 * vineetg: June 2011 6 * -"/proc/meminfo | grep PageTables" kept on increasing 7 * Recently added pgtable dtor was not getting called. 8 * 9 * vineetg: May 2011 10 * -Variable pg-sz means that Page Tables could be variable sized themselves 11 * So calculate it based on addr traversal split [pgd-bits:pte-bits:xxx] 12 * -Page Table size capped to max 1 to save memory - hence verified. 13 * -Since these deal with constants, gcc compile-time optimizes them. 14 * 15 * vineetg: Nov 2010 16 * -Added pgtable ctor/dtor used for pgtable mem accounting 17 * 18 * vineetg: April 2010 19 * -Switched pgtable_t from being struct page * to unsigned long 20 * =Needed so that Page Table allocator (pte_alloc_one) is not forced to 21 * to deal with struct page. Thay way in future we can make it allocate 22 * multiple PG Tbls in one Page Frame 23 * =sweet side effect is avoiding calls to ugly page_address( ) from the 24 * pg-tlb allocator sub-sys (pte_alloc_one, ptr_free, pmd_populate 25 * 26 * Amit Bhor, Sameer Dhavale: Codito Technologies 2004 27 */ 28 29 #ifndef _ASM_ARC_PGALLOC_H 30 #define _ASM_ARC_PGALLOC_H 31 32 #include <linux/mm.h> 33 #include <linux/log2.h> 34 35 static inline void 36 pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd, pte_t *pte) 37 { 38 pmd_set(pmd, pte); 39 } 40 41 static inline void 42 pmd_populate(struct mm_struct *mm, pmd_t *pmd, pgtable_t ptep) 43 { 44 pmd_set(pmd, (pte_t *) ptep); 45 } 46 47 static inline int __get_order_pgd(void) 48 { 49 return get_order(PTRS_PER_PGD * sizeof(pgd_t)); 50 } 51 52 static inline pgd_t *pgd_alloc(struct mm_struct *mm) 53 { 54 int num, num2; 55 pgd_t *ret = (pgd_t *) __get_free_pages(GFP_KERNEL, __get_order_pgd()); 56 57 if (ret) { 58 num = USER_PTRS_PER_PGD + USER_KERNEL_GUTTER / PGDIR_SIZE; 59 memzero(ret, num * sizeof(pgd_t)); 60 61 num2 = VMALLOC_SIZE / PGDIR_SIZE; 62 memcpy(ret + num, swapper_pg_dir + num, num2 * sizeof(pgd_t)); 63 64 memzero(ret + num + num2, 65 (PTRS_PER_PGD - num - num2) * sizeof(pgd_t)); 66 67 } 68 return ret; 69 } 70 71 static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd) 72 { 73 free_pages((unsigned long)pgd, __get_order_pgd()); 74 } 75 76 77 /* 78 * With software-only page-tables, addr-split for traversal is tweakable and 79 * that directly governs how big tables would be at each level. 80 * Further, the MMU page size is configurable. 81 * Thus we need to programatically assert the size constraint 82 * All of this is const math, allowing gcc to do constant folding/propagation. 83 */ 84 85 static inline int __get_order_pte(void) 86 { 87 return get_order(PTRS_PER_PTE * sizeof(pte_t)); 88 } 89 90 static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm) 91 { 92 pte_t *pte; 93 94 pte = (pte_t *) __get_free_pages(GFP_KERNEL | __GFP_ZERO, 95 __get_order_pte()); 96 97 return pte; 98 } 99 100 static inline pgtable_t 101 pte_alloc_one(struct mm_struct *mm) 102 { 103 pgtable_t pte_pg; 104 struct page *page; 105 106 pte_pg = (pgtable_t)__get_free_pages(GFP_KERNEL, __get_order_pte()); 107 if (!pte_pg) 108 return 0; 109 memzero((void *)pte_pg, PTRS_PER_PTE * sizeof(pte_t)); 110 page = virt_to_page(pte_pg); 111 if (!pgtable_page_ctor(page)) { 112 __free_page(page); 113 return 0; 114 } 115 116 return pte_pg; 117 } 118 119 static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte) 120 { 121 free_pages((unsigned long)pte, __get_order_pte()); /* takes phy addr */ 122 } 123 124 static inline void pte_free(struct mm_struct *mm, pgtable_t ptep) 125 { 126 pgtable_page_dtor(virt_to_page(ptep)); 127 free_pages((unsigned long)ptep, __get_order_pte()); 128 } 129 130 #define __pte_free_tlb(tlb, pte, addr) pte_free((tlb)->mm, pte) 131 132 #define check_pgt_cache() do { } while (0) 133 #define pmd_pgtable(pmd) ((pgtable_t) pmd_page_vaddr(pmd)) 134 135 #endif /* _ASM_ARC_PGALLOC_H */ 136