/* 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  /* * If KASLR is enabled, then an offset K is added to the kernel address * space. The bottom 21 bits of this offset are zero to guarantee 2MB * alignment for PA and VA. * * For each pagetable level of the swapper, we know that the shift will * be larger than 21 (for the 4KB granule case we use section maps thus * the smallest shift is actually 30) thus there is the possibility that * KASLR can increase the number of pagetable entries by 1, so we make * room for this extra entry. * * Note KASLR cannot increase the number of required entries for a level * by more than one because it increments both the virtual start and end * addresses equally (the extra entry comes from the case where the end * address is just pushed over a boundary and the start address isn't). */ #ifdef CONFIG_RANDOMIZE_BASE#define EARLY_KASLR	(1)#else#define EARLY_KASLR	(0)#endif #define EARLY_ENTRIES(vstart, vend, shift, add) \	((((vend) - 1) >> (shift)) - ((vstart) >> (shift)) + 1 + 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, EARLY_KASLR)) /* 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)#define SWAPPER_PMD_FLAGS	(PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S) #ifdef CONFIG_ARM64_4K_PAGES#define SWAPPER_RW_MMUFLAGS	(PMD_ATTRINDX(MT_NORMAL) | SWAPPER_PMD_FLAGS)#define SWAPPER_RX_MMUFLAGS	(SWAPPER_RW_MMUFLAGS | PMD_SECT_RDONLY)#else#define SWAPPER_RW_MMUFLAGS	(PTE_ATTRINDX(MT_NORMAL) | SWAPPER_PTE_FLAGS)#define SWAPPER_RX_MMUFLAGS	(SWAPPER_RW_MMUFLAGS | PTE_RDONLY)#endif /* * To make optimal use of block mappings when laying out the linear * mapping, round down the base of physical memory to a size that can * be mapped efficiently, i.e., either PUD_SIZE (4k granule) or PMD_SIZE * (64k granule), or a multiple that can be mapped using contiguous bits * in the page tables: 32 * PMD_SIZE (16k granule) */#if defined(CONFIG_ARM64_4K_PAGES)#define ARM64_MEMSTART_SHIFT		PUD_SHIFT#elif defined(CONFIG_ARM64_16K_PAGES)#define ARM64_MEMSTART_SHIFT		CONT_PMD_SHIFT#else#define ARM64_MEMSTART_SHIFT		PMD_SHIFT#endif /* * sparsemem vmemmap imposes an additional requirement on the alignment of * memstart_addr, due to the fact that the base of the vmemmap region * has a direct correspondence, and needs to appear sufficiently aligned * in the virtual address space. */#if ARM64_MEMSTART_SHIFT < SECTION_SIZE_BITS#define ARM64_MEMSTART_ALIGN	(1UL << SECTION_SIZE_BITS)#else#define ARM64_MEMSTART_ALIGN	(1UL << ARM64_MEMSTART_SHIFT)#endif #endif	/* __ASM_KERNEL_PGTABLE_H */