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authorWill Deacon <will.deacon@arm.com>2017-07-24 11:46:09 +0100
committerWill Deacon <will.deacon@arm.com>2017-07-28 10:32:14 +0100
commit92bbd16e500c85bc210ba48caecbfbdb721bb5b4 (patch)
tree0acd7880c40cc9ff9aa25cfab242d9ba528db6cd /arch/arm64/mm
parentdrivers/perf: arm_pmu: Request PMU SPIs with IRQF_PER_CPU (diff)
downloadlinux-dev-92bbd16e500c85bc210ba48caecbfbdb721bb5b4.tar.xz
linux-dev-92bbd16e500c85bc210ba48caecbfbdb721bb5b4.zip
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.c18
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))) {
/*