1 /* 2 * Page table support for the Hexagon architecture 3 * 4 * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved. 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 and 8 * only version 2 as published by the Free Software Foundation. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program; if not, write to the Free Software 17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 18 * 02110-1301, USA. 19 */ 20 21 #ifndef _ASM_PGALLOC_H 22 #define _ASM_PGALLOC_H 23 24 #include <asm/mem-layout.h> 25 #include <asm/atomic.h> 26 27 #define check_pgt_cache() do {} while (0) 28 29 extern unsigned long long kmap_generation; 30 31 /* 32 * Page table creation interface 33 */ 34 static inline pgd_t *pgd_alloc(struct mm_struct *mm) 35 { 36 pgd_t *pgd; 37 38 pgd = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO); 39 40 /* 41 * There may be better ways to do this, but to ensure 42 * that new address spaces always contain the kernel 43 * base mapping, and to ensure that the user area is 44 * initially marked invalid, initialize the new map 45 * map with a copy of the kernel's persistent map. 46 */ 47 48 memcpy(pgd, swapper_pg_dir, PTRS_PER_PGD*sizeof(pgd_t)); 49 mm->context.generation = kmap_generation; 50 51 /* Physical version is what is passed to virtual machine on switch */ 52 mm->context.ptbase = __pa(pgd); 53 54 return pgd; 55 } 56 57 static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd) 58 { 59 free_page((unsigned long) pgd); 60 } 61 62 static inline struct page *pte_alloc_one(struct mm_struct *mm) 63 { 64 struct page *pte; 65 66 pte = alloc_page(GFP_KERNEL | __GFP_ZERO); 67 if (!pte) 68 return NULL; 69 if (!pgtable_page_ctor(pte)) { 70 __free_page(pte); 71 return NULL; 72 } 73 return pte; 74 } 75 76 /* _kernel variant gets to use a different allocator */ 77 static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm) 78 { 79 gfp_t flags = GFP_KERNEL | __GFP_ZERO; 80 return (pte_t *) __get_free_page(flags); 81 } 82 83 static inline void pte_free(struct mm_struct *mm, struct page *pte) 84 { 85 pgtable_page_dtor(pte); 86 __free_page(pte); 87 } 88 89 static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte) 90 { 91 free_page((unsigned long)pte); 92 } 93 94 static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd, 95 pgtable_t pte) 96 { 97 /* 98 * Conveniently, zero in 3 LSB means indirect 4K page table. 99 * Not so convenient when you're trying to vary the page size. 100 */ 101 set_pmd(pmd, __pmd(((unsigned long)page_to_pfn(pte) << PAGE_SHIFT) | 102 HEXAGON_L1_PTE_SIZE)); 103 } 104 105 /* 106 * Other architectures seem to have ways of making all processes 107 * share the same pmd's for their kernel mappings, but the v0.3 108 * Hexagon VM spec has a "monolithic" L1 table for user and kernel 109 * segments. We track "generations" of the kernel map to minimize 110 * overhead, and update the "slave" copies of the kernel mappings 111 * as part of switch_mm. However, we still need to update the 112 * kernel map of the active thread who's calling pmd_populate_kernel... 113 */ 114 static inline void pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd, 115 pte_t *pte) 116 { 117 extern spinlock_t kmap_gen_lock; 118 pmd_t *ppmd; 119 int pmdindex; 120 121 spin_lock(&kmap_gen_lock); 122 kmap_generation++; 123 mm->context.generation = kmap_generation; 124 current->active_mm->context.generation = kmap_generation; 125 spin_unlock(&kmap_gen_lock); 126 127 set_pmd(pmd, __pmd(((unsigned long)__pa(pte)) | HEXAGON_L1_PTE_SIZE)); 128 129 /* 130 * Now the "slave" copy of the current thread. 131 * This is pointer arithmetic, not byte addresses! 132 */ 133 pmdindex = (pgd_t *)pmd - mm->pgd; 134 ppmd = (pmd_t *)current->active_mm->pgd + pmdindex; 135 set_pmd(ppmd, __pmd(((unsigned long)__pa(pte)) | HEXAGON_L1_PTE_SIZE)); 136 if (pmdindex > max_kernel_seg) 137 max_kernel_seg = pmdindex; 138 } 139 140 #define __pte_free_tlb(tlb, pte, addr) \ 141 do { \ 142 pgtable_page_dtor((pte)); \ 143 tlb_remove_page((tlb), (pte)); \ 144 } while (0) 145 146 #endif 147