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1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * Kernel page table mapping
4 *
5 * Copyright (C) 2015 ARM Ltd.
6 */
7
8#ifndef __ASM_KERNEL_PGTABLE_H
9#define __ASM_KERNEL_PGTABLE_H
10
11#include <asm/boot.h>
12#include <asm/pgtable-hwdef.h>
13#include <asm/sparsemem.h>
14
15/*
16 * The linear mapping and the start of memory are both 2M aligned (per
17 * the arm64 booting.txt requirements). Hence we can use section mapping
18 * with 4K (section size = 2M) but not with 16K (section size = 32M) or
19 * 64K (section size = 512M).
20 */
21
22/*
23 * The idmap and swapper page tables need some space reserved in the kernel
24 * image. Both require pgd, pud (4 levels only) and pmd tables to (section)
25 * map the kernel. With the 64K page configuration, swapper and idmap need to
26 * map to pte level. The swapper also maps the FDT (see __create_page_tables
27 * for more information). Note that the number of ID map translation levels
28 * could be increased on the fly if system RAM is out of reach for the default
29 * VA range, so pages required to map highest possible PA are reserved in all
30 * cases.
31 */
32#ifdef CONFIG_ARM64_4K_PAGES
33#define SWAPPER_PGTABLE_LEVELS (CONFIG_PGTABLE_LEVELS - 1)
34#else
35#define SWAPPER_PGTABLE_LEVELS (CONFIG_PGTABLE_LEVELS)
36#endif
37
38
39/*
40 * A relocatable kernel may execute from an address that differs from the one at
41 * which it was linked. In the worst case, its runtime placement may intersect
42 * with two adjacent PGDIR entries, which means that an additional page table
43 * may be needed at each subordinate level.
44 */
45#define EXTRA_PAGE __is_defined(CONFIG_RELOCATABLE)
46
47#define SPAN_NR_ENTRIES(vstart, vend, shift) \
48 ((((vend) - 1) >> (shift)) - ((vstart) >> (shift)) + 1)
49
50#define EARLY_ENTRIES(vstart, vend, shift, add) \
51 (SPAN_NR_ENTRIES(vstart, vend, shift) + (add))
52
53#define EARLY_PGDS(vstart, vend, add) (EARLY_ENTRIES(vstart, vend, PGDIR_SHIFT, add))
54
55#if SWAPPER_PGTABLE_LEVELS > 3
56#define EARLY_PUDS(vstart, vend, add) (EARLY_ENTRIES(vstart, vend, PUD_SHIFT, add))
57#else
58#define EARLY_PUDS(vstart, vend, add) (0)
59#endif
60
61#if SWAPPER_PGTABLE_LEVELS > 2
62#define EARLY_PMDS(vstart, vend, add) (EARLY_ENTRIES(vstart, vend, SWAPPER_TABLE_SHIFT, add))
63#else
64#define EARLY_PMDS(vstart, vend, add) (0)
65#endif
66
67#define EARLY_PAGES(vstart, vend, add) ( 1 /* PGDIR page */ \
68 + EARLY_PGDS((vstart), (vend), add) /* each PGDIR needs a next level page table */ \
69 + EARLY_PUDS((vstart), (vend), add) /* each PUD needs a next level page table */ \
70 + EARLY_PMDS((vstart), (vend), add)) /* each PMD needs a next level page table */
71#define INIT_DIR_SIZE (PAGE_SIZE * EARLY_PAGES(KIMAGE_VADDR, _end, EXTRA_PAGE))
72
73/* the initial ID map may need two extra pages if it needs to be extended */
74#if VA_BITS < 48
75#define INIT_IDMAP_DIR_SIZE ((INIT_IDMAP_DIR_PAGES + 2) * PAGE_SIZE)
76#else
77#define INIT_IDMAP_DIR_SIZE (INIT_IDMAP_DIR_PAGES * PAGE_SIZE)
78#endif
79#define INIT_IDMAP_DIR_PAGES EARLY_PAGES(KIMAGE_VADDR, _end + MAX_FDT_SIZE + SWAPPER_BLOCK_SIZE, 1)
80
81/* Initial memory map size */
82#ifdef CONFIG_ARM64_4K_PAGES
83#define SWAPPER_BLOCK_SHIFT PMD_SHIFT
84#define SWAPPER_BLOCK_SIZE PMD_SIZE
85#define SWAPPER_TABLE_SHIFT PUD_SHIFT
86#else
87#define SWAPPER_BLOCK_SHIFT PAGE_SHIFT
88#define SWAPPER_BLOCK_SIZE PAGE_SIZE
89#define SWAPPER_TABLE_SHIFT PMD_SHIFT
90#endif
91
92/*
93 * Initial memory map attributes.
94 */
95#define SWAPPER_PTE_FLAGS (PTE_TYPE_PAGE | PTE_AF | PTE_SHARED | PTE_UXN)
96#define SWAPPER_PMD_FLAGS (PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S | PTE_UXN)
97
98#ifdef CONFIG_ARM64_4K_PAGES
99#define SWAPPER_RW_MMUFLAGS (PMD_ATTRINDX(MT_NORMAL) | SWAPPER_PMD_FLAGS | PTE_WRITE)
100#define SWAPPER_RX_MMUFLAGS (SWAPPER_RW_MMUFLAGS | PMD_SECT_RDONLY)
101#else
102#define SWAPPER_RW_MMUFLAGS (PTE_ATTRINDX(MT_NORMAL) | SWAPPER_PTE_FLAGS | PTE_WRITE)
103#define SWAPPER_RX_MMUFLAGS (SWAPPER_RW_MMUFLAGS | PTE_RDONLY)
104#endif
105
106#endif /* __ASM_KERNEL_PGTABLE_H */