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/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 */