mirror of
git://git.yoctoproject.org/linux-yocto.git
synced 2025-07-19 12:19:01 +02:00
e6128a8e52
Even though we support loading kernels anywhere in 48-bit addressable physical memory, we create the ID maps based on the number of levels that we happened to configure for the kernel VA and user VA spaces. The reason for this is that the PGD/PUD/PMD based classification of translation levels, along with the associated folding when the number of levels is less than 5, does not permit creating a page table hierarchy of a set number of levels. This means that, for instance, on 39-bit VA kernels we need to configure an additional level above PGD level on the fly, and 36-bit VA kernels still only support 47-bit virtual addressing with this trick applied. Now that we have a separate helper to populate page table hierarchies that does not define the levels in terms of PUDS/PMDS/etc at all, let's reuse it to create the permanent ID map with a fixed VA size of 48 bits. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Link: https://lore.kernel.org/r/20240214122845.2033971-64-ardb+git@google.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
119 lines
4.2 KiB
C
119 lines
4.2 KiB
C
/* 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 linear mapping and the start of memory are both 2M aligned (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).
|
|
*/
|
|
|
|
/*
|
|
* The idmap and swapper page tables need some space reserved in the kernel
|
|
* image. Both require pgd, pud (4 levels only) and pmd tables to (section)
|
|
* map the kernel. With the 64K page configuration, swapper and idmap need to
|
|
* map to pte level. The swapper also maps the FDT (see __create_page_tables
|
|
* for more information). Note that the number of ID map translation levels
|
|
* could be increased on the fly if system RAM is out of reach for the default
|
|
* VA range, so pages required to map highest possible PA are reserved in all
|
|
* cases.
|
|
*/
|
|
#ifdef CONFIG_ARM64_4K_PAGES
|
|
#define SWAPPER_PGTABLE_LEVELS (CONFIG_PGTABLE_LEVELS - 1)
|
|
#else
|
|
#define SWAPPER_PGTABLE_LEVELS (CONFIG_PGTABLE_LEVELS)
|
|
#endif
|
|
|
|
#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_PGDS(vstart, vend, add) (EARLY_ENTRIES(vstart, vend, PGDIR_SHIFT, add))
|
|
|
|
#if SWAPPER_PGTABLE_LEVELS > 3
|
|
#define EARLY_PUDS(vstart, vend, add) (EARLY_ENTRIES(vstart, vend, PUD_SHIFT, add))
|
|
#else
|
|
#define EARLY_PUDS(vstart, vend, add) (0)
|
|
#endif
|
|
|
|
#if SWAPPER_PGTABLE_LEVELS > 2
|
|
#define EARLY_PMDS(vstart, vend, add) (EARLY_ENTRIES(vstart, vend, SWAPPER_TABLE_SHIFT, add))
|
|
#else
|
|
#define EARLY_PMDS(vstart, vend, add) (0)
|
|
#endif
|
|
|
|
#define EARLY_PAGES(vstart, vend, add) ( 1 /* PGDIR page */ \
|
|
+ EARLY_PGDS((vstart), (vend), add) /* each PGDIR needs a next level page table */ \
|
|
+ EARLY_PUDS((vstart), (vend), add) /* each PUD needs a next level page table */ \
|
|
+ EARLY_PMDS((vstart), (vend), add)) /* each PMD needs a next level page table */
|
|
#define INIT_DIR_SIZE (PAGE_SIZE * (EARLY_PAGES(KIMAGE_VADDR, _end, EXTRA_PAGE) + EARLY_SEGMENT_EXTRA_PAGES))
|
|
|
|
/* the initial ID map may need two extra pages if it needs to be extended */
|
|
#if VA_BITS < 48
|
|
#define INIT_IDMAP_DIR_SIZE ((INIT_IDMAP_DIR_PAGES + 2) * PAGE_SIZE)
|
|
#else
|
|
#define INIT_IDMAP_DIR_SIZE (INIT_IDMAP_DIR_PAGES * PAGE_SIZE)
|
|
#endif
|
|
#define INIT_IDMAP_DIR_PAGES EARLY_PAGES(KIMAGE_VADDR, _end + MAX_FDT_SIZE + SWAPPER_BLOCK_SIZE, 1)
|
|
|
|
/* Initial memory map size */
|
|
#ifdef CONFIG_ARM64_4K_PAGES
|
|
#define SWAPPER_BLOCK_SHIFT PMD_SHIFT
|
|
#define SWAPPER_BLOCK_SIZE PMD_SIZE
|
|
#define SWAPPER_TABLE_SHIFT PUD_SHIFT
|
|
#else
|
|
#define SWAPPER_BLOCK_SHIFT PAGE_SHIFT
|
|
#define SWAPPER_BLOCK_SIZE PAGE_SIZE
|
|
#define SWAPPER_TABLE_SHIFT PMD_SHIFT
|
|
#endif
|
|
|
|
/* 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)
|
|
#else
|
|
#define EARLY_SEGMENT_EXTRA_PAGES 0
|
|
#endif
|
|
|
|
/*
|
|
* Initial memory map attributes.
|
|
*/
|
|
#define SWAPPER_PTE_FLAGS (PTE_TYPE_PAGE | PTE_AF | PTE_SHARED | PTE_UXN)
|
|
#define SWAPPER_PMD_FLAGS (PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S | PTE_UXN)
|
|
|
|
#ifdef CONFIG_ARM64_4K_PAGES
|
|
#define SWAPPER_RW_MMUFLAGS (PMD_ATTRINDX(MT_NORMAL) | SWAPPER_PMD_FLAGS | PTE_WRITE)
|
|
#define SWAPPER_RX_MMUFLAGS (SWAPPER_RW_MMUFLAGS | PMD_SECT_RDONLY)
|
|
#else
|
|
#define SWAPPER_RW_MMUFLAGS (PTE_ATTRINDX(MT_NORMAL) | SWAPPER_PTE_FLAGS | PTE_WRITE)
|
|
#define SWAPPER_RX_MMUFLAGS (SWAPPER_RW_MMUFLAGS | PTE_RDONLY)
|
|
#endif
|
|
|
|
#endif /* __ASM_KERNEL_PGTABLE_H */
|