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/kernel/vmlinux.lds.S | |
| 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/kernel/vmlinux.lds.S')
| -rw-r--r-- | arch/arm/kernel/vmlinux.lds.S | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/arch/arm/kernel/vmlinux.lds.S b/arch/arm/kernel/vmlinux.lds.S index 6f57cb94367f..18fd68a295ea 100644 --- a/arch/arm/kernel/vmlinux.lds.S +++ b/arch/arm/kernel/vmlinux.lds.S @@ -8,6 +8,9 @@ #include <asm/thread_info.h> #include <asm/memory.h> #include <asm/page.h> +#ifdef CONFIG_ARM_KERNMEM_PERMS +#include <asm/pgtable.h> +#endif #define PROC_INFO \ . = ALIGN(4); \ @@ -90,6 +93,11 @@ SECTIONS _text = .; HEAD_TEXT } + +#ifdef CONFIG_ARM_KERNMEM_PERMS + . = ALIGN(1<<SECTION_SHIFT); +#endif + .text : { /* Real text segment */ _stext = .; /* Text and read-only data */ __exception_text_start = .; @@ -145,7 +153,11 @@ SECTIONS _etext = .; /* End of text and rodata section */ #ifndef CONFIG_XIP_KERNEL +# ifdef CONFIG_ARM_KERNMEM_PERMS + . = ALIGN(1<<SECTION_SHIFT); +# else . = ALIGN(PAGE_SIZE); +# endif __init_begin = .; #endif /* @@ -220,7 +232,11 @@ SECTIONS . = PAGE_OFFSET + TEXT_OFFSET; #else __init_end = .; +#ifdef CONFIG_ARM_KERNMEM_PERMS + . = ALIGN(1<<SECTION_SHIFT); +#else . = ALIGN(THREAD_SIZE); +#endif __data_loc = .; #endif |