Linux kernel mirror (for testing)
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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 physical and virtual addresses of the start of the kernel image are
17 * equal modulo 2 MiB (per the arm64 booting.txt requirements). Hence we can
18 * use section mapping with 4K (section size = 2M) but not with 16K (section
19 * size = 32M) or 64K (section size = 512M).
20 */
21#if defined(PMD_SIZE) && PMD_SIZE <= MIN_KIMG_ALIGN
22#define SWAPPER_BLOCK_SHIFT PMD_SHIFT
23#define SWAPPER_SKIP_LEVEL 1
24#else
25#define SWAPPER_BLOCK_SHIFT PAGE_SHIFT
26#define SWAPPER_SKIP_LEVEL 0
27#endif
28#define SWAPPER_BLOCK_SIZE (UL(1) << SWAPPER_BLOCK_SHIFT)
29
30#define SWAPPER_PGTABLE_LEVELS (CONFIG_PGTABLE_LEVELS - SWAPPER_SKIP_LEVEL)
31#define INIT_IDMAP_PGTABLE_LEVELS (IDMAP_LEVELS - SWAPPER_SKIP_LEVEL)
32
33#define IDMAP_VA_BITS 48
34#define IDMAP_LEVELS ARM64_HW_PGTABLE_LEVELS(IDMAP_VA_BITS)
35#define IDMAP_ROOT_LEVEL (4 - IDMAP_LEVELS)
36
37/*
38 * A relocatable kernel may execute from an address that differs from the one at
39 * which it was linked. In the worst case, its runtime placement may intersect
40 * with two adjacent PGDIR entries, which means that an additional page table
41 * may be needed at each subordinate level.
42 */
43#define EXTRA_PAGE __is_defined(CONFIG_RELOCATABLE)
44
45#define SPAN_NR_ENTRIES(vstart, vend, shift) \
46 ((((vend) - 1) >> (shift)) - ((vstart) >> (shift)) + 1)
47
48#define EARLY_ENTRIES(lvl, vstart, vend) \
49 SPAN_NR_ENTRIES(vstart, vend, SWAPPER_BLOCK_SHIFT + lvl * PTDESC_TABLE_SHIFT)
50
51#define EARLY_LEVEL(lvl, lvls, vstart, vend, add) \
52 ((lvls) > (lvl) ? EARLY_ENTRIES(lvl, vstart, vend) + (add) : 0)
53
54#define EARLY_PAGES(lvls, vstart, vend, add) (1 /* PGDIR page */ \
55 + EARLY_LEVEL(3, (lvls), (vstart), (vend), add) /* each entry needs a next level page table */ \
56 + EARLY_LEVEL(2, (lvls), (vstart), (vend), add) /* each entry needs a next level page table */ \
57 + EARLY_LEVEL(1, (lvls), (vstart), (vend), add))/* each entry needs a next level page table */
58#define INIT_DIR_SIZE (PAGE_SIZE * (EARLY_PAGES(SWAPPER_PGTABLE_LEVELS, KIMAGE_VADDR, _end, EXTRA_PAGE) \
59 + EARLY_SEGMENT_EXTRA_PAGES))
60
61#define INIT_IDMAP_DIR_PAGES (EARLY_PAGES(INIT_IDMAP_PGTABLE_LEVELS, KIMAGE_VADDR, kimage_limit, 1))
62#define INIT_IDMAP_DIR_SIZE ((INIT_IDMAP_DIR_PAGES + EARLY_IDMAP_EXTRA_PAGES) * PAGE_SIZE)
63
64#define INIT_IDMAP_FDT_PAGES (EARLY_PAGES(INIT_IDMAP_PGTABLE_LEVELS, 0UL, UL(MAX_FDT_SIZE), 1) - 1)
65#define INIT_IDMAP_FDT_SIZE ((INIT_IDMAP_FDT_PAGES + EARLY_IDMAP_EXTRA_FDT_PAGES) * PAGE_SIZE)
66
67/* The number of segments in the kernel image (text, rodata, inittext, initdata, data+bss) */
68#define KERNEL_SEGMENT_COUNT 5
69
70#if SWAPPER_BLOCK_SIZE > SEGMENT_ALIGN
71#define EARLY_SEGMENT_EXTRA_PAGES (KERNEL_SEGMENT_COUNT + 1)
72/*
73 * The initial ID map consists of the kernel image, mapped as two separate
74 * segments, and may appear misaligned wrt the swapper block size. This means
75 * we need 3 additional pages. The DT could straddle a swapper block boundary,
76 * so it may need 2.
77 */
78#define EARLY_IDMAP_EXTRA_PAGES 3
79#define EARLY_IDMAP_EXTRA_FDT_PAGES 2
80#else
81#define EARLY_SEGMENT_EXTRA_PAGES 0
82#define EARLY_IDMAP_EXTRA_PAGES 0
83#define EARLY_IDMAP_EXTRA_FDT_PAGES 0
84#endif
85
86#endif /* __ASM_KERNEL_PGTABLE_H */