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