On Mon, Dec 18, 2017 at 12:42:17PM +0100, Thomas Gleixner wrote:
> From: Andy Lutomirski <l...@kernel.org>
>
> The kernel is very erratic as to which pagetables have _PAGE_USER set. The
> vsyscall page gets lucky: it seems that all of the relevant pagetables are
> among the apparently arbitrary ones that set _PAGE_USER. Rather than
> relying on chance, just explicitly set _PAGE_USER.
>
> This will let us clean up pagetable setup to stop setting _PAGE_USER. The
> added code can also be reused by pagetable isolation to manage the
> _PAGE_USER bit in the usermode tables.
>
> Signed-off-by: Andy Lutomirski <l...@kernel.org>
> Signed-off-by: Ingo Molnar <mi...@kernel.org>
> Signed-off-by: Thomas Gleixner <t...@linutronix.de>
> Cc: Borislav Petkov <b...@alien8.de>
> Cc: Brian Gerst <brge...@gmail.com>
> Cc: David Laight <david.lai...@aculab.com>
> Cc: Kees Cook <keesc...@chromium.org>
> Cc: Linus Torvalds <torva...@linux-foundation.org>
> Cc: Peter Zijlstra <pet...@infradead.org>
> Cc: Thomas Gleixner <t...@linutronix.de>
> ---
> arch/x86/entry/vsyscall/vsyscall_64.c | 33
> ++++++++++++++++++++++++++++++++-
> 1 file changed, 32 insertions(+), 1 deletion(-)
Nice.
Reviewed-by: Borislav Petkov <b...@suse.de>
--
Regards/Gruss,
Boris.
SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284
(AG Nürnberg)
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