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 * deal with struct page. That 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 /* 39 * The cast to long below is OK in 32-bit PAE40 regime with long long pte 40 * Despite "wider" pte, the pte table needs to be in non-PAE low memory 41 * as all higher levels can only hold long pointers. 42 * 43 * The cast itself is needed given simplistic definition of set_pmd() 44 */ 45 set_pmd(pmd, __pmd((unsigned long)pte)); 46 } 47 48 static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd, pgtable_t pte) 49 { 50 set_pmd(pmd, __pmd((unsigned long)pte)); 51 } 52 53 static inline int __get_order_pgd(void) 54 { 55 return get_order(PTRS_PER_PGD * sizeof(pgd_t)); 56 } 57 58 static inline pgd_t *pgd_alloc(struct mm_struct *mm) 59 { 60 int num, num2; 61 pgd_t *ret = (pgd_t *) __get_free_pages(GFP_KERNEL, __get_order_pgd()); 62 63 if (ret) { 64 num = USER_PTRS_PER_PGD + USER_KERNEL_GUTTER / PGDIR_SIZE; 65 memzero(ret, num * sizeof(pgd_t)); 66 67 num2 = VMALLOC_SIZE / PGDIR_SIZE; 68 memcpy(ret + num, swapper_pg_dir + num, num2 * sizeof(pgd_t)); 69 70 memzero(ret + num + num2, 71 (PTRS_PER_PGD - num - num2) * sizeof(pgd_t)); 72 73 } 74 return ret; 75 } 76 77 static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd) 78 { 79 free_pages((unsigned long)pgd, __get_order_pgd()); 80 } 81 82 83 /* 84 * With software-only page-tables, addr-split for traversal is tweakable and 85 * that directly governs how big tables would be at each level. 86 * Further, the MMU page size is configurable. 87 * Thus we need to programatically assert the size constraint 88 * All of this is const math, allowing gcc to do constant folding/propagation. 89 */ 90 91 static inline int __get_order_pte(void) 92 { 93 return get_order(PTRS_PER_PTE * sizeof(pte_t)); 94 } 95 96 static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm) 97 { 98 pte_t *pte; 99 100 pte = (pte_t *) __get_free_pages(GFP_KERNEL | __GFP_ZERO, 101 __get_order_pte()); 102 103 return pte; 104 } 105 106 static inline pgtable_t 107 pte_alloc_one(struct mm_struct *mm) 108 { 109 pgtable_t pte_pg; 110 struct page *page; 111 112 pte_pg = (pgtable_t)__get_free_pages(GFP_KERNEL, __get_order_pte()); 113 if (!pte_pg) 114 return 0; 115 memzero((void *)pte_pg, PTRS_PER_PTE * sizeof(pte_t)); 116 page = virt_to_page(pte_pg); 117 if (!pgtable_pte_page_ctor(page)) { 118 __free_page(page); 119 return 0; 120 } 121 122 return pte_pg; 123 } 124 125 static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte) 126 { 127 free_pages((unsigned long)pte, __get_order_pte()); /* takes phy addr */ 128 } 129 130 static inline void pte_free(struct mm_struct *mm, pgtable_t ptep) 131 { 132 pgtable_pte_page_dtor(virt_to_page(ptep)); 133 free_pages((unsigned long)ptep, __get_order_pte()); 134 } 135 136 #define __pte_free_tlb(tlb, pte, addr) pte_free((tlb)->mm, pte) 137 138 #endif /* _ASM_ARC_PGALLOC_H */ 139