Linux kernel mirror (for testing)
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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 */