diff options
| author | Kees Cook <keescook@chromium.org> | 2013-10-10 17:18:18 -0700 |
|---|---|---|
| committer | H. Peter Anvin <hpa@linux.intel.com> | 2013-10-13 03:13:13 -0700 |
| commit | 6145cfe394a7f138f6b64491c5663f97dba12450 (patch) | |
| tree | 409c39dce2121c84fd1a96102a16e7d69c20285c /arch/x86/include/asm/page_64_types.h | |
| parent | f32360ef6608434a032dc7ad262d45e9693c27f3 (diff) | |
x86, kaslr: Raise the maximum virtual address to -1 GiB on x86_64
On 64-bit, this raises the maximum location to -1 GiB (from -1.5 GiB),
the upper limit currently, since the kernel fixmap page mappings need
to be moved to use the other 1 GiB (which would be the theoretical
limit when building with -mcmodel=kernel).
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: http://lkml.kernel.org/r/1381450698-28710-7-git-send-email-keescook@chromium.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Diffstat (limited to 'arch/x86/include/asm/page_64_types.h')
| -rw-r--r-- | arch/x86/include/asm/page_64_types.h | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/arch/x86/include/asm/page_64_types.h b/arch/x86/include/asm/page_64_types.h index 43dcd804ebd5..8de6d9cf3b95 100644 --- a/arch/x86/include/asm/page_64_types.h +++ b/arch/x86/include/asm/page_64_types.h @@ -39,9 +39,18 @@ #define __VIRTUAL_MASK_SHIFT 47 /* - * Kernel image size is limited to 512 MB (see level2_kernel_pgt in - * arch/x86/kernel/head_64.S), and it is mapped here: + * Kernel image size is limited to 1GiB due to the fixmap living in the + * next 1GiB (see level2_kernel_pgt in arch/x86/kernel/head_64.S). Use + * 512MiB by default, leaving 1.5GiB for modules once the page tables + * are fully set up. If kernel ASLR is configured, it can extend the + * kernel page table mapping, reducing the size of the modules area. */ -#define KERNEL_IMAGE_SIZE (512 * 1024 * 1024) +#define KERNEL_IMAGE_SIZE_DEFAULT (512 * 1024 * 1024) +#if defined(CONFIG_RANDOMIZE_BASE) && \ + CONFIG_RANDOMIZE_BASE_MAX_OFFSET > KERNEL_IMAGE_SIZE_DEFAULT +#define KERNEL_IMAGE_SIZE CONFIG_RANDOMIZE_BASE_MAX_OFFSET +#else +#define KERNEL_IMAGE_SIZE KERNEL_IMAGE_SIZE_DEFAULT +#endif #endif /* _ASM_X86_PAGE_64_DEFS_H */ |