diff options
| -rw-r--r-- | arch/x86/kernel/head64.c | 3 | ||||
| -rw-r--r-- | arch/x86/kernel/head_64.S | 7 | ||||
| -rw-r--r-- | arch/x86/mm/init_64.c | 27 | ||||
| -rw-r--r-- | include/asm-x86/pgtable_64.h | 1 |
4 files changed, 37 insertions, 1 deletions
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c index 24dbf56..ad24408 100644 --- a/arch/x86/kernel/head64.c +++ b/arch/x86/kernel/head64.c @@ -88,6 +88,9 @@ void __init x86_64_start_kernel(char * real_mode_data) /* Make NULL pointers segfault */ zap_identity_mappings(); + /* Cleanup the over mapped high alias */ + cleanup_highmap(); + for (i = 0; i < IDT_ENTRIES; i++) { #ifdef CONFIG_EARLY_PRINTK set_intr_gate(i, &early_idt_handlers[i]); diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S index 09b38d5..53e5820 100644 --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -107,8 +107,13 @@ startup_64: movq %rdx, 0(%rbx, %rax, 8) ident_complete: - /* Fixup the kernel text+data virtual addresses + /* + * Fixup the kernel text+data virtual addresses. Note that + * we might write invalid pmds, when the kernel is relocated + * cleanup_highmap() fixes this up along with the mappings + * beyond _end. */ + leaq level2_kernel_pgt(%rip), %rdi leaq 4096(%rdi), %r8 /* See if it is a valid page table entry */ diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index a4a9ccc..bb652f5 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) diff --git a/include/asm-x86/pgtable_64.h b/include/asm-x86/pgtable_64.h index bd4740a..7fd5e0e 100644 --- a/include/asm-x86/pgtable_64.h +++ b/include/asm-x86/pgtable_64.h @@ -246,6 +246,7 @@ static inline int pud_large(pud_t pte) #define __swp_entry_to_pte(x) ((pte_t) { .pte = (x).val }) extern int kern_addr_valid(unsigned long addr); +extern void cleanup_highmap(void); #define io_remap_pfn_range(vma, vaddr, pfn, size, prot) \ remap_pfn_range(vma, vaddr, pfn, size, prot) |