1 /* 2 * Kernel page table mapping 3 * 4 * Copyright (C) 2015 ARM Ltd. 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 as 8 * 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, see <http://www.gnu.org/licenses/>. 17 */ 18 19 #ifndef __ASM_KERNEL_PGTABLE_H 20 #define __ASM_KERNEL_PGTABLE_H 21 22 #include <asm/sparsemem.h> 23 24 /* 25 * The linear mapping and the start of memory are both 2M aligned (per 26 * the arm64 booting.txt requirements). Hence we can use section mapping 27 * with 4K (section size = 2M) but not with 16K (section size = 32M) or 28 * 64K (section size = 512M). 29 */ 30 #ifdef CONFIG_ARM64_4K_PAGES 31 #define ARM64_SWAPPER_USES_SECTION_MAPS 1 32 #else 33 #define ARM64_SWAPPER_USES_SECTION_MAPS 0 34 #endif 35 36 /* 37 * The idmap and swapper page tables need some space reserved in the kernel 38 * image. Both require pgd, pud (4 levels only) and pmd tables to (section) 39 * map the kernel. With the 64K page configuration, swapper and idmap need to 40 * map to pte level. The swapper also maps the FDT (see __create_page_tables 41 * for more information). Note that the number of ID map translation levels 42 * could be increased on the fly if system RAM is out of reach for the default 43 * VA range, so pages required to map highest possible PA are reserved in all 44 * cases. 45 */ 46 #if ARM64_SWAPPER_USES_SECTION_MAPS 47 #define SWAPPER_PGTABLE_LEVELS (CONFIG_PGTABLE_LEVELS - 1) 48 #define IDMAP_PGTABLE_LEVELS (ARM64_HW_PGTABLE_LEVELS(PHYS_MASK_SHIFT) - 1) 49 #else 50 #define SWAPPER_PGTABLE_LEVELS (CONFIG_PGTABLE_LEVELS) 51 #define IDMAP_PGTABLE_LEVELS (ARM64_HW_PGTABLE_LEVELS(PHYS_MASK_SHIFT)) 52 #endif 53 54 #define SWAPPER_DIR_SIZE (SWAPPER_PGTABLE_LEVELS * PAGE_SIZE) 55 #define IDMAP_DIR_SIZE (IDMAP_PGTABLE_LEVELS * PAGE_SIZE) 56 57 /* Initial memory map size */ 58 #if ARM64_SWAPPER_USES_SECTION_MAPS 59 #define SWAPPER_BLOCK_SHIFT SECTION_SHIFT 60 #define SWAPPER_BLOCK_SIZE SECTION_SIZE 61 #define SWAPPER_TABLE_SHIFT PUD_SHIFT 62 #else 63 #define SWAPPER_BLOCK_SHIFT PAGE_SHIFT 64 #define SWAPPER_BLOCK_SIZE PAGE_SIZE 65 #define SWAPPER_TABLE_SHIFT PMD_SHIFT 66 #endif 67 68 /* The size of the initial kernel direct mapping */ 69 #define SWAPPER_INIT_MAP_SIZE (_AC(1, UL) << SWAPPER_TABLE_SHIFT) 70 71 /* 72 * Initial memory map attributes. 73 */ 74 #define SWAPPER_PTE_FLAGS (PTE_TYPE_PAGE | PTE_AF | PTE_SHARED) 75 #define SWAPPER_PMD_FLAGS (PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S) 76 77 #if ARM64_SWAPPER_USES_SECTION_MAPS 78 #define SWAPPER_MM_MMUFLAGS (PMD_ATTRINDX(MT_NORMAL) | SWAPPER_PMD_FLAGS) 79 #else 80 #define SWAPPER_MM_MMUFLAGS (PTE_ATTRINDX(MT_NORMAL) | SWAPPER_PTE_FLAGS) 81 #endif 82 83 /* 84 * To make optimal use of block mappings when laying out the linear 85 * mapping, round down the base of physical memory to a size that can 86 * be mapped efficiently, i.e., either PUD_SIZE (4k granule) or PMD_SIZE 87 * (64k granule), or a multiple that can be mapped using contiguous bits 88 * in the page tables: 32 * PMD_SIZE (16k granule) 89 */ 90 #if defined(CONFIG_ARM64_4K_PAGES) 91 #define ARM64_MEMSTART_SHIFT PUD_SHIFT 92 #elif defined(CONFIG_ARM64_16K_PAGES) 93 #define ARM64_MEMSTART_SHIFT (PMD_SHIFT + 5) 94 #else 95 #define ARM64_MEMSTART_SHIFT PMD_SHIFT 96 #endif 97 98 /* 99 * sparsemem vmemmap imposes an additional requirement on the alignment of 100 * memstart_addr, due to the fact that the base of the vmemmap region 101 * has a direct correspondence, and needs to appear sufficiently aligned 102 * in the virtual address space. 103 */ 104 #if defined(CONFIG_SPARSEMEM_VMEMMAP) && ARM64_MEMSTART_SHIFT < SECTION_SIZE_BITS 105 #define ARM64_MEMSTART_ALIGN (1UL << SECTION_SIZE_BITS) 106 #else 107 #define ARM64_MEMSTART_ALIGN (1UL << ARM64_MEMSTART_SHIFT) 108 #endif 109 110 #endif /* __ASM_KERNEL_PGTABLE_H */ 111