1 /* SPDX-License-Identifier: GPL-2.0-only */
3 * Kernel page table mapping
5 * Copyright (C) 2015 ARM Ltd.
8 #ifndef __ASM_KERNEL_PGTABLE_H
9 #define __ASM_KERNEL_PGTABLE_H
12 #include <asm/pgtable-hwdef.h>
13 #include <asm/sparsemem.h>
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).
21 #if defined(PMD_SIZE) && PMD_SIZE <= MIN_KIMG_ALIGN
22 #define SWAPPER_BLOCK_SHIFT PMD_SHIFT
23 #define SWAPPER_SKIP_LEVEL 1
25 #define SWAPPER_BLOCK_SHIFT PAGE_SHIFT
26 #define SWAPPER_SKIP_LEVEL 0
28 #define SWAPPER_BLOCK_SIZE (UL(1) << SWAPPER_BLOCK_SHIFT)
29 #define SWAPPER_TABLE_SHIFT (SWAPPER_BLOCK_SHIFT + PAGE_SHIFT - 3)
31 #define SWAPPER_PGTABLE_LEVELS (CONFIG_PGTABLE_LEVELS - SWAPPER_SKIP_LEVEL)
32 #define INIT_IDMAP_PGTABLE_LEVELS (IDMAP_LEVELS - SWAPPER_SKIP_LEVEL)
34 #define IDMAP_VA_BITS 48
35 #define IDMAP_LEVELS ARM64_HW_PGTABLE_LEVELS(IDMAP_VA_BITS)
36 #define IDMAP_ROOT_LEVEL (4 - IDMAP_LEVELS)
39 * A relocatable kernel may execute from an address that differs from the one at
40 * which it was linked. In the worst case, its runtime placement may intersect
41 * with two adjacent PGDIR entries, which means that an additional page table
42 * may be needed at each subordinate level.
44 #define EXTRA_PAGE __is_defined(CONFIG_RELOCATABLE)
46 #define SPAN_NR_ENTRIES(vstart, vend, shift) \
47 ((((vend) - 1) >> (shift)) - ((vstart) >> (shift)) + 1)
49 #define EARLY_ENTRIES(vstart, vend, shift, add) \
50 (SPAN_NR_ENTRIES(vstart, vend, shift) + (add))
52 #define EARLY_LEVEL(lvl, lvls, vstart, vend, add) \
53 (lvls > lvl ? EARLY_ENTRIES(vstart, vend, SWAPPER_BLOCK_SHIFT + lvl * (PAGE_SHIFT - 3), add) : 0)
55 #define EARLY_PAGES(lvls, vstart, vend, add) (1 /* PGDIR page */ \
56 + EARLY_LEVEL(3, (lvls), (vstart), (vend), add) /* each entry needs a next level page table */ \
57 + EARLY_LEVEL(2, (lvls), (vstart), (vend), add) /* each entry needs a next level page table */ \
58 + EARLY_LEVEL(1, (lvls), (vstart), (vend), add))/* each entry needs a next level page table */
59 #define INIT_DIR_SIZE (PAGE_SIZE * (EARLY_PAGES(SWAPPER_PGTABLE_LEVELS, KIMAGE_VADDR, _end, EXTRA_PAGE) \
60 + EARLY_SEGMENT_EXTRA_PAGES))
62 #define INIT_IDMAP_DIR_PAGES (EARLY_PAGES(INIT_IDMAP_PGTABLE_LEVELS, KIMAGE_VADDR, _end, 1))
63 #define INIT_IDMAP_DIR_SIZE ((INIT_IDMAP_DIR_PAGES + EARLY_IDMAP_EXTRA_PAGES) * PAGE_SIZE)
65 #define INIT_IDMAP_FDT_PAGES (EARLY_PAGES(INIT_IDMAP_PGTABLE_LEVELS, 0UL, UL(MAX_FDT_SIZE), 1) - 1)
66 #define INIT_IDMAP_FDT_SIZE ((INIT_IDMAP_FDT_PAGES + EARLY_IDMAP_EXTRA_FDT_PAGES) * PAGE_SIZE)
68 /* The number of segments in the kernel image (text, rodata, inittext, initdata, data+bss) */
69 #define KERNEL_SEGMENT_COUNT 5
71 #if SWAPPER_BLOCK_SIZE > SEGMENT_ALIGN
72 #define EARLY_SEGMENT_EXTRA_PAGES (KERNEL_SEGMENT_COUNT + 1)
74 * The initial ID map consists of the kernel image, mapped as two separate
75 * segments, and may appear misaligned wrt the swapper block size. This means
76 * we need 3 additional pages. The DT could straddle a swapper block boundary,
79 #define EARLY_IDMAP_EXTRA_PAGES 3
80 #define EARLY_IDMAP_EXTRA_FDT_PAGES 2
82 #define EARLY_SEGMENT_EXTRA_PAGES 0
83 #define EARLY_IDMAP_EXTRA_PAGES 0
84 #define EARLY_IDMAP_EXTRA_FDT_PAGES 0
87 #endif /* __ASM_KERNEL_PGTABLE_H */