[PATCH v2 0/2] Determine kernel text mapping size at runtime for x86_64

From: Baoquan He
Date: Fri Dec 09 2016 - 09:42:11 EST


The current kernel sets KERNEL_IMAGE_SIZE as 1G as long as CONFIG_RANDOMIZE_BASE
is enabled, though people specify "nokaslr" into cmdline to disable kaslr
explicitly. This could be a wrong behaviour. CONFIG_RANDOMIZE_BASE should only
decide if KASLR code need be compiled in. If user specify "nokaslr", kernel should
should behave as no KASLR code compiled in at all.

So in this patchset, made changes to determine the size of kernel text mapping
area at runtime. If "nokaslr" specified, kernel mapping size is 512M though
CONFIG_RANDOMIZE_BASE is enabled.


Baoquan He (2):
x86/64: Make kernel text mapping always take one whole page table in
early boot code
x86/KASLR/64: Determine kernel text mapping size at runtime

arch/x86/boot/compressed/kaslr.c | 20 +++++++++++++++-----
arch/x86/include/asm/kaslr.h | 1 +
arch/x86/include/asm/page_64_types.h | 20 ++++++++++++--------
arch/x86/include/asm/pgtable_64_types.h | 2 +-
arch/x86/kernel/head64.c | 11 ++++++-----
arch/x86/kernel/head_64.S | 16 +++++++++-------
arch/x86/mm/dump_pagetables.c | 3 ++-
arch/x86/mm/init_64.c | 2 +-
arch/x86/mm/physaddr.c | 6 +++---
9 files changed, 50 insertions(+), 31 deletions(-)

--
2.5.5