diff options
Diffstat (limited to 'arch/x86/mm/init_64.c')
| -rw-r--r-- | arch/x86/mm/init_64.c | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index a4a9cccdd4f..bb652f5a93f 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -171,6 +171,33 @@ set_pte_phys(unsigned long vaddr, unsigned long phys, pgprot_t prot) __flush_tlb_one(vaddr); } +/* + * The head.S code sets up the kernel high mapping from: + * __START_KERNEL_map to __START_KERNEL_map + KERNEL_TEXT_SIZE + * + * phys_addr holds the negative offset to the kernel, which is added + * to the compile time generated pmds. This results in invalid pmds up + * to the point where we hit the physaddr 0 mapping. + * + * We limit the mappings to the region from _text to _end. _end is + * rounded up to the 2MB boundary. This catches the invalid pmds as + * well, as they are located before _text: + */ +void __init cleanup_highmap(void) +{ + unsigned long vaddr = __START_KERNEL_map; + unsigned long end = round_up((unsigned long)_end, PMD_SIZE) - 1; + pmd_t *pmd = level2_kernel_pgt; + pmd_t *last_pmd = pmd + PTRS_PER_PMD; + + for (; pmd < last_pmd; pmd++, vaddr += PMD_SIZE) { + if (!pmd_present(*pmd)) + continue; + if (vaddr < (unsigned long) _text || vaddr > end) + set_pmd(pmd, __pmd(0)); + } +} + /* NOTE: this is meant to be run only at boot */ void __init __set_fixmap(enum fixed_addresses idx, unsigned long phys, pgprot_t prot) |