Re: [GIT PULL] xen: Check NX state before setting up GDT mapping

From: Ingo Molnar
Date: Wed Sep 23 2009 - 08:36:08 EST



* Jeremy Fitzhardinge <jeremy@xxxxxxxx> wrote:

> Hi Ingo,
>
> This is a little followup fix to the previous Xen stack-protector
> patches to deal with the case of a 64-bit processor without NX support
> (either old Intel or disabled in BIOS). Before creating the mapping for
> the GDT we need to make sure that NX is actually supported or the
> processor will fault on us.
>
> This ends up making mm/init.o non-stack-protected. Given that this file
> has some fairly complex functions with local arrays, I've made an
> additional change to move the NX setup into its own file to limit the
> non-stack-protected code. I added it as a later delta so that the pure
> bugfix can be applied to stable, and the cleanup can go on top into
> mainline.
>
> Thanks,
> J
>
> The following changes since commit 79b520e87e1214cfa107bdc8528b5d6c055a8b82:
> Linus Torvalds (1):
> Merge branch 'for-linus' of git://oss.sgi.com/xfs/xfs
>
> are available in the git repository at:
>
> git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen.git bugfix
>
> Jeremy Fitzhardinge (2):
> xen: check EFER for NX before setting up GDT mapping
> x86: split NX setup into separate file to limit unstack-protected code
>
> arch/x86/include/asm/pgtable_types.h | 1 +
> arch/x86/mm/Makefile | 3 +-
> arch/x86/mm/init.c | 63 -------------------------------
> arch/x86/mm/setup_nx.c | 69 ++++++++++++++++++++++++++++++++++
> arch/x86/xen/enlighten.c | 10 ++--
> 5 files changed, 77 insertions(+), 69 deletions(-)
> create mode 100644 arch/x86/mm/setup_nx.c

Pulled, thanks Jeremy!

Ingo
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