[SRU][Trusty][PATCH 3/7] x86: require x86-64 for automatic NUMA balancing

[Juerg Haefliger]

From: Mel Gorman <mgorman at suse.de>

32-bit support for NUMA is an oddity on its own but with automatic NUMA
balancing on top there is a reasonable risk that the CPUPID information
cannot be stored in the page flags.  This patch removes support for
automatic NUMA support on 32-bit x86.

Signed-off-by: Mel Gorman <mgorman at suse.de>
Cc: David Vrabel <david.vrabel at citrix.com>
Cc: Ingo Molnar <mingo at kernel.org>
Cc: Peter Anvin <hpa at zytor.com>
Cc: Fengguang Wu <fengguang.wu at intel.com>
Cc: Linus Torvalds <torvalds at linux-foundation.org>
Cc: Steven Noonan <steven at uplinklabs.net>
Cc: Rik van Riel <riel at redhat.com>
Cc: Peter Zijlstra <peterz at infradead.org>
Cc: Andrea Arcangeli <aarcange at redhat.com>
Cc: Dave Hansen <dave.hansen at intel.com>
Cc: Srikar Dronamraju <srikar at linux.vnet.ibm.com>
Cc: Cyrill Gorcunov <gorcunov at gmail.com>
Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds at linux-foundation.org>

CVE-2018-3620
CVE-2018-3646

(cherry picked from commit 4468dd76f51f8be75d4f04f1d721e379596e7262)
Signed-off-by: Juerg Haefliger <juergh at canonical.com>
---
 arch/x86/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 15fa347d3ced..5b7ab646d6a6 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -25,7 +25,7 @@ config X86
 	select ARCH_MIGHT_HAVE_PC_PARPORT
 	select HAVE_AOUT if X86_32
 	select HAVE_UNSTABLE_SCHED_CLOCK
-	select ARCH_SUPPORTS_NUMA_BALANCING
+	select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
 	select ARCH_SUPPORTS_INT128 if X86_64
 	select ARCH_WANTS_PROT_NUMA_PROT_NONE
 	select HAVE_IDE
-- 
2.17.1