diff options
| author | Kees Cook <keescook@chromium.org> | 2014-04-03 17:28:11 -0700 |
|---|---|---|
| committer | Kees Cook <keescook@chromium.org> | 2014-10-16 14:38:54 -0700 |
| commit | 1e6b48116a95046ec51f3d40f83aff8b006674d7 (patch) | |
| tree | 1c18e08416613ef84513cb2cd52679e7af6d4d7c /arch/arm/mm/mmu.c | |
| parent | 23a4e4050ba9c98ab67db0980a9fb20e5096d9ea (diff) | |
ARM: mm: allow non-text sections to be non-executable
Adds CONFIG_ARM_KERNMEM_PERMS to separate the kernel memory regions
into section-sized areas that can have different permisions. Performs
the NX permission changes during free_initmem, so that init memory can be
reclaimed.
This uses section size instead of PMD size to reduce memory lost to
padding on non-LPAE systems.
Based on work by Brad Spengler, Larry Bassel, and Laura Abbott.
Signed-off-by: Kees Cook <keescook@chromium.org>
Tested-by: Laura Abbott <lauraa@codeaurora.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
Diffstat (limited to 'arch/arm/mm/mmu.c')
| -rw-r--r-- | arch/arm/mm/mmu.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c index bdf5c94f7c36..1c52c8e94372 100644 --- a/arch/arm/mm/mmu.c +++ b/arch/arm/mm/mmu.c @@ -1373,13 +1373,20 @@ static void __init map_lowmem(void) if (start >= end) break; - if (end < kernel_x_start || start >= kernel_x_end) { + if (end < kernel_x_start) { map.pfn = __phys_to_pfn(start); map.virtual = __phys_to_virt(start); map.length = end - start; map.type = MT_MEMORY_RWX; create_mapping(&map); + } else if (start >= kernel_x_end) { + map.pfn = __phys_to_pfn(start); + map.virtual = __phys_to_virt(start); + map.length = end - start; + map.type = MT_MEMORY_RW; + + create_mapping(&map); } else { /* This better cover the entire kernel */ if (start < kernel_x_start) { |