diff options
Diffstat (limited to 'arch/arm64/include/asm/kernel-pgtable.h')
| -rw-r--r-- | arch/arm64/include/asm/kernel-pgtable.h | 27 |
1 files changed, 6 insertions, 21 deletions
diff --git a/arch/arm64/include/asm/kernel-pgtable.h b/arch/arm64/include/asm/kernel-pgtable.h index 85d26143faa5..83ddb14b95a5 100644 --- a/arch/arm64/include/asm/kernel-pgtable.h +++ b/arch/arm64/include/asm/kernel-pgtable.h @@ -37,27 +37,12 @@ /* - * 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). + * 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. */ - -#ifdef CONFIG_RANDOMIZE_BASE -#define EARLY_KASLR (1) -#else -#define EARLY_KASLR (0) -#endif +#define EXTRA_PAGE __is_defined(CONFIG_RELOCATABLE) #define SPAN_NR_ENTRIES(vstart, vend, shift) \ ((((vend) - 1) >> (shift)) - ((vstart) >> (shift)) + 1) @@ -83,7 +68,7 @@ + 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)) +#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 |