88 lines
3.4 KiB
C
88 lines
3.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Kernel page table mapping
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*
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* Copyright (C) 2015 ARM Ltd.
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*/
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#ifndef __ASM_KERNEL_PGTABLE_H
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#define __ASM_KERNEL_PGTABLE_H
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#include <asm/boot.h>
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#include <asm/pgtable-hwdef.h>
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#include <asm/sparsemem.h>
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/*
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* The physical and virtual addresses of the start of the kernel image are
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* equal modulo 2 MiB (per the arm64 booting.txt requirements). Hence we can
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* use section mapping with 4K (section size = 2M) but not with 16K (section
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* size = 32M) or 64K (section size = 512M).
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*/
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#if defined(PMD_SIZE) && PMD_SIZE <= MIN_KIMG_ALIGN
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#define SWAPPER_BLOCK_SHIFT PMD_SHIFT
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#define SWAPPER_SKIP_LEVEL 1
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#else
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#define SWAPPER_BLOCK_SHIFT PAGE_SHIFT
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#define SWAPPER_SKIP_LEVEL 0
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#endif
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#define SWAPPER_BLOCK_SIZE (UL(1) << SWAPPER_BLOCK_SHIFT)
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#define SWAPPER_TABLE_SHIFT (SWAPPER_BLOCK_SHIFT + PAGE_SHIFT - 3)
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#define SWAPPER_PGTABLE_LEVELS (CONFIG_PGTABLE_LEVELS - SWAPPER_SKIP_LEVEL)
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#define INIT_IDMAP_PGTABLE_LEVELS (IDMAP_LEVELS - SWAPPER_SKIP_LEVEL)
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#define IDMAP_VA_BITS 48
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#define IDMAP_LEVELS ARM64_HW_PGTABLE_LEVELS(IDMAP_VA_BITS)
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#define IDMAP_ROOT_LEVEL (4 - IDMAP_LEVELS)
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/*
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* A relocatable kernel may execute from an address that differs from the one at
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* which it was linked. In the worst case, its runtime placement may intersect
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* with two adjacent PGDIR entries, which means that an additional page table
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* may be needed at each subordinate level.
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*/
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#define EXTRA_PAGE __is_defined(CONFIG_RELOCATABLE)
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#define SPAN_NR_ENTRIES(vstart, vend, shift) \
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((((vend) - 1) >> (shift)) - ((vstart) >> (shift)) + 1)
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#define EARLY_ENTRIES(vstart, vend, shift, add) \
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(SPAN_NR_ENTRIES(vstart, vend, shift) + (add))
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#define EARLY_LEVEL(lvl, lvls, vstart, vend, add) \
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(lvls > lvl ? EARLY_ENTRIES(vstart, vend, SWAPPER_BLOCK_SHIFT + lvl * (PAGE_SHIFT - 3), add) : 0)
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#define EARLY_PAGES(lvls, vstart, vend, add) (1 /* PGDIR page */ \
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+ EARLY_LEVEL(3, (lvls), (vstart), (vend), add) /* each entry needs a next level page table */ \
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+ EARLY_LEVEL(2, (lvls), (vstart), (vend), add) /* each entry needs a next level page table */ \
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+ EARLY_LEVEL(1, (lvls), (vstart), (vend), add))/* each entry needs a next level page table */
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#define INIT_DIR_SIZE (PAGE_SIZE * (EARLY_PAGES(SWAPPER_PGTABLE_LEVELS, KIMAGE_VADDR, _end, EXTRA_PAGE) \
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+ EARLY_SEGMENT_EXTRA_PAGES))
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#define INIT_IDMAP_DIR_PAGES (EARLY_PAGES(INIT_IDMAP_PGTABLE_LEVELS, KIMAGE_VADDR, _end, 1))
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#define INIT_IDMAP_DIR_SIZE ((INIT_IDMAP_DIR_PAGES + EARLY_IDMAP_EXTRA_PAGES) * PAGE_SIZE)
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#define INIT_IDMAP_FDT_PAGES (EARLY_PAGES(INIT_IDMAP_PGTABLE_LEVELS, 0UL, UL(MAX_FDT_SIZE), 1) - 1)
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#define INIT_IDMAP_FDT_SIZE ((INIT_IDMAP_FDT_PAGES + EARLY_IDMAP_EXTRA_FDT_PAGES) * PAGE_SIZE)
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/* The number of segments in the kernel image (text, rodata, inittext, initdata, data+bss) */
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#define KERNEL_SEGMENT_COUNT 5
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#if SWAPPER_BLOCK_SIZE > SEGMENT_ALIGN
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#define EARLY_SEGMENT_EXTRA_PAGES (KERNEL_SEGMENT_COUNT + 1)
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/*
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* The initial ID map consists of the kernel image, mapped as two separate
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* segments, and may appear misaligned wrt the swapper block size. This means
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* we need 3 additional pages. The DT could straddle a swapper block boundary,
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* so it may need 2.
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*/
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#define EARLY_IDMAP_EXTRA_PAGES 3
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#define EARLY_IDMAP_EXTRA_FDT_PAGES 2
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#else
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#define EARLY_SEGMENT_EXTRA_PAGES 0
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#define EARLY_IDMAP_EXTRA_PAGES 0
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#define EARLY_IDMAP_EXTRA_FDT_PAGES 0
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#endif
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#endif /* __ASM_KERNEL_PGTABLE_H */
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