diff options
Diffstat (limited to 'arch/arm64/include/asm/kernel-pgtable.h')
| -rw-r--r-- | arch/arm64/include/asm/kernel-pgtable.h | 47 |
1 files changed, 46 insertions, 1 deletions
diff --git a/arch/arm64/include/asm/kernel-pgtable.h b/arch/arm64/include/asm/kernel-pgtable.h index 7803343e5881..a780f6714b44 100644 --- a/arch/arm64/include/asm/kernel-pgtable.h +++ b/arch/arm64/include/asm/kernel-pgtable.h @@ -52,7 +52,52 @@ #define IDMAP_PGTABLE_LEVELS (ARM64_HW_PGTABLE_LEVELS(PHYS_MASK_SHIFT)) #endif -#define SWAPPER_DIR_SIZE (SWAPPER_PGTABLE_LEVELS * PAGE_SIZE) + +/* + * 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) >> (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 |