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/pgtable.h> 23 #include <asm/sparsemem.h> 24 25 /* 26 * The linear mapping and the start of memory are both 2M aligned (per 27 * the arm64 booting.txt requirements). Hence we can use section mapping 28 * with 4K (section size = 2M) but not with 16K (section size = 32M) or 29 * 64K (section size = 512M). 30 */ 31 #ifdef CONFIG_ARM64_4K_PAGES 32 #define ARM64_SWAPPER_USES_SECTION_MAPS 1 33 #else 34 #define ARM64_SWAPPER_USES_SECTION_MAPS 0 35 #endif 36 37 /* 38 * The idmap and swapper page tables need some space reserved in the kernel 39 * image. Both require pgd, pud (4 levels only) and pmd tables to (section) 40 * map the kernel. With the 64K page configuration, swapper and idmap need to 41 * map to pte level. The swapper also maps the FDT (see __create_page_tables 42 * for more information). Note that the number of ID map translation levels 43 * could be increased on the fly if system RAM is out of reach for the default 44 * VA range, so pages required to map highest possible PA are reserved in all 45 * cases. 46 */ 47 #if ARM64_SWAPPER_USES_SECTION_MAPS 48 #define SWAPPER_PGTABLE_LEVELS (CONFIG_PGTABLE_LEVELS - 1) 49 #define IDMAP_PGTABLE_LEVELS (ARM64_HW_PGTABLE_LEVELS(PHYS_MASK_SHIFT) - 1) 50 #else 51 #define SWAPPER_PGTABLE_LEVELS (CONFIG_PGTABLE_LEVELS) 52 #define IDMAP_PGTABLE_LEVELS (ARM64_HW_PGTABLE_LEVELS(PHYS_MASK_SHIFT)) 53 #endif 54 55 #define SWAPPER_DIR_SIZE (SWAPPER_PGTABLE_LEVELS * PAGE_SIZE) 56 #define IDMAP_DIR_SIZE (IDMAP_PGTABLE_LEVELS * PAGE_SIZE) 57 58 #ifdef CONFIG_ARM64_SW_TTBR0_PAN 59 #define RESERVED_TTBR0_SIZE (PAGE_SIZE) 60 #else 61 #define RESERVED_TTBR0_SIZE (0) 62 #endif 63 64 /* Initial memory map size */ 65 #if ARM64_SWAPPER_USES_SECTION_MAPS 66 #define SWAPPER_BLOCK_SHIFT SECTION_SHIFT 67 #define SWAPPER_BLOCK_SIZE SECTION_SIZE 68 #define SWAPPER_TABLE_SHIFT PUD_SHIFT 69 #else 70 #define SWAPPER_BLOCK_SHIFT PAGE_SHIFT 71 #define SWAPPER_BLOCK_SIZE PAGE_SIZE 72 #define SWAPPER_TABLE_SHIFT PMD_SHIFT 73 #endif 74 75 /* The size of the initial kernel direct mapping */ 76 #define SWAPPER_INIT_MAP_SIZE (_AC(1, UL) << SWAPPER_TABLE_SHIFT) 77 78 /* 79 * Initial memory map attributes. 80 */ 81 #define SWAPPER_PTE_FLAGS (PTE_TYPE_PAGE | PTE_AF | PTE_SHARED) 82 #define SWAPPER_PMD_FLAGS (PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S) 83 84 #if ARM64_SWAPPER_USES_SECTION_MAPS 85 #define SWAPPER_MM_MMUFLAGS (PMD_ATTRINDX(MT_NORMAL) | SWAPPER_PMD_FLAGS) 86 #else 87 #define SWAPPER_MM_MMUFLAGS (PTE_ATTRINDX(MT_NORMAL) | SWAPPER_PTE_FLAGS) 88 #endif 89 90 /* 91 * To make optimal use of block mappings when laying out the linear 92 * mapping, round down the base of physical memory to a size that can 93 * be mapped efficiently, i.e., either PUD_SIZE (4k granule) or PMD_SIZE 94 * (64k granule), or a multiple that can be mapped using contiguous bits 95 * in the page tables: 32 * PMD_SIZE (16k granule) 96 */ 97 #if defined(CONFIG_ARM64_4K_PAGES) 98 #define ARM64_MEMSTART_SHIFT PUD_SHIFT 99 #elif defined(CONFIG_ARM64_16K_PAGES) 100 #define ARM64_MEMSTART_SHIFT (PMD_SHIFT + 5) 101 #else 102 #define ARM64_MEMSTART_SHIFT PMD_SHIFT 103 #endif 104 105 /* 106 * sparsemem vmemmap imposes an additional requirement on the alignment of 107 * memstart_addr, due to the fact that the base of the vmemmap region 108 * has a direct correspondence, and needs to appear sufficiently aligned 109 * in the virtual address space. 110 */ 111 #if defined(CONFIG_SPARSEMEM_VMEMMAP) && ARM64_MEMSTART_SHIFT < SECTION_SIZE_BITS 112 #define ARM64_MEMSTART_ALIGN (1UL << SECTION_SIZE_BITS) 113 #else 114 #define ARM64_MEMSTART_ALIGN (1UL << ARM64_MEMSTART_SHIFT) 115 #endif 116 117 #endif /* __ASM_KERNEL_PGTABLE_H */ 118