From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Nick Desaulniers <ndesaulniers@google.com>
Date: Wed, 3 Jan 2018 12:39:52 -0800
Subject: [PATCH] x86/process: Define cpu_tss_rw in same section as declaration
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CVE-2017-5754

cpu_tss_rw is declared with DECLARE_PER_CPU_PAGE_ALIGNED
but then defined with DEFINE_PER_CPU_SHARED_ALIGNED
leading to section mismatch warnings.

Use DEFINE_PER_CPU_PAGE_ALIGNED consistently. This is necessary because
it's mapped to the cpu entry area and must be page aligned.

[ tglx: Massaged changelog a bit ]

Fixes: 1a935bc3d4ea ("x86/entry: Move SYSENTER_stack to the beginning of struct tss_struct")
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: thomas.lendacky@amd.com
Cc: Borislav Petkov <bpetkov@suse.de>
Cc: tklauser@distanz.ch
Cc: minipli@googlemail.com
Cc: me@kylehuey.com
Cc: namit@vmware.com
Cc: luto@kernel.org
Cc: jpoimboe@redhat.com
Cc: tj@kernel.org
Cc: cl@linux.com
Cc: bp@suse.de
Cc: thgarnie@google.com
Cc: kirill.shutemov@linux.intel.com
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20180103203954.183360-1-ndesaulniers@google.com

(cherry picked from commit 2fd9c41aea47f4ad071accf94b94f94f2c4d31eb)
Signed-off-by: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
(cherry picked from commit f45e574914ae47825d2eea46abc9d6fbabe55e56)
Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
---
 arch/x86/kernel/process.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 3688a7b9d055..07e6218ad7d9 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -46,7 +46,7 @@
  * section. Since TSS's are completely CPU-local, we want them
  * on exact cacheline boundaries, to eliminate cacheline ping-pong.
  */
-__visible DEFINE_PER_CPU_SHARED_ALIGNED(struct tss_struct, cpu_tss_rw) = {
+__visible DEFINE_PER_CPU_PAGE_ALIGNED(struct tss_struct, cpu_tss_rw) = {
 	.x86_tss = {
 		/*
 		 * .sp0 is only used when entering ring 0 from a lower
-- 
2.14.2

