diff options
| author | Will Deacon <will.deacon@arm.com> | 2017-07-24 11:46:09 +0100 |
|---|---|---|
| committer | Will Deacon <will.deacon@arm.com> | 2017-07-28 10:32:14 +0100 |
| commit | 92bbd16e500c85bc210ba48caecbfbdb721bb5b4 (patch) | |
| tree | 0acd7880c40cc9ff9aa25cfab242d9ba528db6cd /arch/arm64/mm | |
| parent | a3287c41ff405025bc57b165a0f6cd698bbbc1be (diff) | |
arm64: mmu: Place guard page after mapping of kernel image
The vast majority of virtual allocations in the vmalloc region are followed
by a guard page, which can help to avoid overruning on vma into another,
which may map a read-sensitive device.
This patch adds a guard page to the end of the kernel image mapping (i.e.
following the data/bss segments).
Cc: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'arch/arm64/mm')
| -rw-r--r-- | arch/arm64/mm/mmu.c | 18 |
1 files changed, 11 insertions, 7 deletions
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 23c2d89a362e..f1eb15e0e864 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -496,7 +496,7 @@ void mark_rodata_ro(void) static void __init map_kernel_segment(pgd_t *pgd, void *va_start, void *va_end, pgprot_t prot, struct vm_struct *vma, - int flags) + int flags, unsigned long vm_flags) { phys_addr_t pa_start = __pa_symbol(va_start); unsigned long size = va_end - va_start; @@ -507,10 +507,13 @@ static void __init map_kernel_segment(pgd_t *pgd, void *va_start, void *va_end, __create_pgd_mapping(pgd, pa_start, (unsigned long)va_start, size, prot, early_pgtable_alloc, flags); + if (!(vm_flags & VM_NO_GUARD)) + size += PAGE_SIZE; + vma->addr = va_start; vma->phys_addr = pa_start; vma->size = size; - vma->flags = VM_MAP; + vma->flags = VM_MAP | vm_flags; vma->caller = __builtin_return_address(0); vm_area_add_early(vma); @@ -541,14 +544,15 @@ static void __init map_kernel(pgd_t *pgd) * Only rodata will be remapped with different permissions later on, * all other segments are allowed to use contiguous mappings. */ - map_kernel_segment(pgd, _text, _etext, text_prot, &vmlinux_text, 0); + map_kernel_segment(pgd, _text, _etext, text_prot, &vmlinux_text, 0, + VM_NO_GUARD); map_kernel_segment(pgd, __start_rodata, __inittext_begin, PAGE_KERNEL, - &vmlinux_rodata, NO_CONT_MAPPINGS); + &vmlinux_rodata, NO_CONT_MAPPINGS, VM_NO_GUARD); map_kernel_segment(pgd, __inittext_begin, __inittext_end, text_prot, - &vmlinux_inittext, 0); + &vmlinux_inittext, 0, VM_NO_GUARD); map_kernel_segment(pgd, __initdata_begin, __initdata_end, PAGE_KERNEL, - &vmlinux_initdata, 0); - map_kernel_segment(pgd, _data, _end, PAGE_KERNEL, &vmlinux_data, 0); + &vmlinux_initdata, 0, VM_NO_GUARD); + map_kernel_segment(pgd, _data, _end, PAGE_KERNEL, &vmlinux_data, 0, 0); if (!pgd_val(*pgd_offset_raw(pgd, FIXADDR_START))) { /* |