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Diffstat (limited to 'arch/arm64/include/asm/kernel-pgtable.h')
| -rw-r--r-- | arch/arm64/include/asm/kernel-pgtable.h | 162 |
1 files changed, 162 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/kernel-pgtable.h b/arch/arm64/include/asm/kernel-pgtable.h new file mode 100644 index 000000000..74ab40b76 --- /dev/null +++ b/arch/arm64/include/asm/kernel-pgtable.h @@ -0,0 +1,162 @@ +/* + * Kernel page table mapping + * + * Copyright (C) 2015 ARM Ltd. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#ifndef __ASM_KERNEL_PGTABLE_H +#define __ASM_KERNEL_PGTABLE_H + +#include <asm/pgtable.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). + */ +#ifdef CONFIG_ARM64_4K_PAGES +#define ARM64_SWAPPER_USES_SECTION_MAPS 1 +#else +#define ARM64_SWAPPER_USES_SECTION_MAPS 0 +#endif + +/* + * 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. + */ +#if ARM64_SWAPPER_USES_SECTION_MAPS +#define SWAPPER_PGTABLE_LEVELS (CONFIG_PGTABLE_LEVELS - 1) +#define IDMAP_PGTABLE_LEVELS (ARM64_HW_PGTABLE_LEVELS(PHYS_MASK_SHIFT) - 1) +#else +#define SWAPPER_PGTABLE_LEVELS (CONFIG_PGTABLE_LEVELS) +#define IDMAP_PGTABLE_LEVELS (ARM64_HW_PGTABLE_LEVELS(PHYS_MASK_SHIFT)) +#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) \ + ((((vend) - 1) >> (shift)) - ((vstart) >> (shift)) + 1 + EARLY_KASLR) + +#define EARLY_PGDS(vstart, vend) (EARLY_ENTRIES(vstart, vend, PGDIR_SHIFT)) + +#if SWAPPER_PGTABLE_LEVELS > 3 +#define EARLY_PUDS(vstart, vend) (EARLY_ENTRIES(vstart, vend, PUD_SHIFT)) +#else +#define EARLY_PUDS(vstart, vend) (0) +#endif + +#if SWAPPER_PGTABLE_LEVELS > 2 +#define EARLY_PMDS(vstart, vend) (EARLY_ENTRIES(vstart, vend, SWAPPER_TABLE_SHIFT)) +#else +#define EARLY_PMDS(vstart, vend) (0) +#endif + +#define EARLY_PAGES(vstart, vend) ( 1 /* PGDIR page */ \ + + EARLY_PGDS((vstart), (vend)) /* each PGDIR needs a next level page table */ \ + + EARLY_PUDS((vstart), (vend)) /* each PUD needs a next level page table */ \ + + EARLY_PMDS((vstart), (vend))) /* each PMD needs a next level page table */ +#define SWAPPER_DIR_SIZE (PAGE_SIZE * EARLY_PAGES(KIMAGE_VADDR + TEXT_OFFSET, _end)) +#define IDMAP_DIR_SIZE (IDMAP_PGTABLE_LEVELS * PAGE_SIZE) + +#ifdef CONFIG_ARM64_SW_TTBR0_PAN +#define RESERVED_TTBR0_SIZE (PAGE_SIZE) +#else +#define RESERVED_TTBR0_SIZE (0) +#endif + +/* Initial memory map size */ +#if ARM64_SWAPPER_USES_SECTION_MAPS +#define SWAPPER_BLOCK_SHIFT SECTION_SHIFT +#define SWAPPER_BLOCK_SIZE SECTION_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 size of the initial kernel direct mapping */ +#define SWAPPER_INIT_MAP_SIZE (_AC(1, UL) << SWAPPER_TABLE_SHIFT) + +/* + * 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) + +#if ARM64_SWAPPER_USES_SECTION_MAPS +#define SWAPPER_MM_MMUFLAGS (PMD_ATTRINDX(MT_NORMAL) | SWAPPER_PMD_FLAGS) +#else +#define SWAPPER_MM_MMUFLAGS (PTE_ATTRINDX(MT_NORMAL) | SWAPPER_PTE_FLAGS) +#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 (PMD_SHIFT + 5) +#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 defined(CONFIG_SPARSEMEM_VMEMMAP) && 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 */ |