On Fri, Nov 23, 2018 at 02:53:21PM +0300, Kirill A. Shutemov wrote:
On Mon, Nov 19, 2018 at 12:23:51PM +0000, gregkh@xxxxxxxxxxxxxxxxxxx wrote:
The patch below does not apply to the 4.18-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
From b413460931ab36e958ee127522653cd16f7a248c Mon Sep 17 00:00:00 2001
From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Date: Fri, 26 Oct 2018 15:28:54 +0300
Subject: [PATCH 1/2] x86/mm: Move LDT remap out of KASLR region on 5-level
paging
commit d52888aa2753e3063a9d3a0c9f72f94aa9809c15 upstream
On 5-level paging the LDT remap area is placed in the middle of the KASLR
randomization region and it can overlap with the direct mapping, the
vmalloc or the vmap area.
The LDT mapping is per mm, so it cannot be moved into the P4D page table
next to the CPU_ENTRY_AREA without complicating PGD table allocation for
5-level paging.
The 4 PGD slot gap just before the direct mapping is reserved for
hypervisors, so it cannot be used.
Move the direct mapping one slot deeper and use the resulting gap for the
LDT remap area. The resulting layout is the same for 4 and 5 level paging.
[ tglx: Massaged changelog ]
Fixes: f55f0501cbf6 ("x86/pti: Put the LDT in its own PGD if PTI is on")
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reviewed-by: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: bp@xxxxxxxxx
Cc: hpa@xxxxxxxxx
Cc: dave.hansen@xxxxxxxxxxxxxxx
Cc: peterz@xxxxxxxxxxxxx
Cc: boris.ostrovsky@xxxxxxxxxx
Cc: jgross@xxxxxxxx
Cc: bhe@xxxxxxxxxx
Cc: willy@xxxxxxxxxxxxx
Cc: linux-mm@xxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx
Link: https://lkml.kernel.org/r/20181026122856.66224-2-kirill.shutemov@xxxxxxxxxxxxxxx
Queued for 4.18, thank you.
--
Thanks,
Sasha
