name : kernel-pgtable.h /* 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 /* * 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)) /* 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 /* * 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 */