1 /* SPDX-License-Identifier: GPL-2.0-only */
3 * Kernel page table mapping
5 * Copyright (C) 2015 ARM Ltd.
8 #ifndef __ASM_KERNEL_PGTABLE_H
9 #define __ASM_KERNEL_PGTABLE_H
12 #include <asm/pgtable-hwdef.h>
13 #include <asm/sparsemem.h>
16 * The linear mapping and the start of memory are both 2M aligned (per
17 * the arm64 booting.txt requirements). Hence we can use section mapping
18 * with 4K (section size = 2M) but not with 16K (section size = 32M) or
19 * 64K (section size = 512M).
23 * The idmap and swapper page tables need some space reserved in the kernel
24 * image. Both require pgd, pud (4 levels only) and pmd tables to (section)
25 * map the kernel. With the 64K page configuration, swapper and idmap need to
26 * map to pte level. The swapper also maps the FDT (see __create_page_tables
27 * for more information). Note that the number of ID map translation levels
28 * could be increased on the fly if system RAM is out of reach for the default
29 * VA range, so pages required to map highest possible PA are reserved in all
32 #ifdef CONFIG_ARM64_4K_PAGES
33 #define SWAPPER_PGTABLE_LEVELS (CONFIG_PGTABLE_LEVELS - 1)
35 #define SWAPPER_PGTABLE_LEVELS (CONFIG_PGTABLE_LEVELS)
40 * If KASLR is enabled, then an offset K is added to the kernel address
41 * space. The bottom 21 bits of this offset are zero to guarantee 2MB
42 * alignment for PA and VA.
44 * For each pagetable level of the swapper, we know that the shift will
45 * be larger than 21 (for the 4KB granule case we use section maps thus
46 * the smallest shift is actually 30) thus there is the possibility that
47 * KASLR can increase the number of pagetable entries by 1, so we make
48 * room for this extra entry.
50 * Note KASLR cannot increase the number of required entries for a level
51 * by more than one because it increments both the virtual start and end
52 * addresses equally (the extra entry comes from the case where the end
53 * address is just pushed over a boundary and the start address isn't).
56 #ifdef CONFIG_RANDOMIZE_BASE
57 #define EARLY_KASLR (1)
59 #define EARLY_KASLR (0)
62 #define SPAN_NR_ENTRIES(vstart, vend, shift) \
63 ((((vend) - 1) >> (shift)) - ((vstart) >> (shift)) + 1)
65 #define EARLY_ENTRIES(vstart, vend, shift, add) \
66 (SPAN_NR_ENTRIES(vstart, vend, shift) + (add))
68 #define EARLY_PGDS(vstart, vend, add) (EARLY_ENTRIES(vstart, vend, PGDIR_SHIFT, add))
70 #if SWAPPER_PGTABLE_LEVELS > 3
71 #define EARLY_PUDS(vstart, vend, add) (EARLY_ENTRIES(vstart, vend, PUD_SHIFT, add))
73 #define EARLY_PUDS(vstart, vend, add) (0)
76 #if SWAPPER_PGTABLE_LEVELS > 2
77 #define EARLY_PMDS(vstart, vend, add) (EARLY_ENTRIES(vstart, vend, SWAPPER_TABLE_SHIFT, add))
79 #define EARLY_PMDS(vstart, vend, add) (0)
82 #define EARLY_PAGES(vstart, vend, add) ( 1 /* PGDIR page */ \
83 + EARLY_PGDS((vstart), (vend), add) /* each PGDIR needs a next level page table */ \
84 + EARLY_PUDS((vstart), (vend), add) /* each PUD needs a next level page table */ \
85 + EARLY_PMDS((vstart), (vend), add)) /* each PMD needs a next level page table */
86 #define INIT_DIR_SIZE (PAGE_SIZE * EARLY_PAGES(KIMAGE_VADDR, _end, EARLY_KASLR))
88 /* the initial ID map may need two extra pages if it needs to be extended */
90 #define INIT_IDMAP_DIR_SIZE ((INIT_IDMAP_DIR_PAGES + 2) * PAGE_SIZE)
92 #define INIT_IDMAP_DIR_SIZE (INIT_IDMAP_DIR_PAGES * PAGE_SIZE)
94 #define INIT_IDMAP_DIR_PAGES EARLY_PAGES(KIMAGE_VADDR, _end + MAX_FDT_SIZE + SWAPPER_BLOCK_SIZE, 1)
96 /* Initial memory map size */
97 #ifdef CONFIG_ARM64_4K_PAGES
98 #define SWAPPER_BLOCK_SHIFT PMD_SHIFT
99 #define SWAPPER_BLOCK_SIZE PMD_SIZE
100 #define SWAPPER_TABLE_SHIFT PUD_SHIFT
102 #define SWAPPER_BLOCK_SHIFT PAGE_SHIFT
103 #define SWAPPER_BLOCK_SIZE PAGE_SIZE
104 #define SWAPPER_TABLE_SHIFT PMD_SHIFT
108 * Initial memory map attributes.
110 #define SWAPPER_PTE_FLAGS (PTE_TYPE_PAGE | PTE_AF | PTE_SHARED | PTE_UXN)
111 #define SWAPPER_PMD_FLAGS (PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S | PTE_UXN)
113 #ifdef CONFIG_ARM64_4K_PAGES
114 #define SWAPPER_RW_MMUFLAGS (PMD_ATTRINDX(MT_NORMAL) | SWAPPER_PMD_FLAGS | PTE_WRITE)
115 #define SWAPPER_RX_MMUFLAGS (SWAPPER_RW_MMUFLAGS | PMD_SECT_RDONLY)
117 #define SWAPPER_RW_MMUFLAGS (PTE_ATTRINDX(MT_NORMAL) | SWAPPER_PTE_FLAGS | PTE_WRITE)
118 #define SWAPPER_RX_MMUFLAGS (SWAPPER_RW_MMUFLAGS | PTE_RDONLY)
121 #endif /* __ASM_KERNEL_PGTABLE_H */