aboutsummaryrefslogtreecommitdiffstats
path: root/common/recipes-kernel/linux/linux-yocto-4.9.21/0041-kaiser-Set-_PAGE_NX-only-if-supported.patch
blob: fefefa119099a8f0e230d0a0f8498b47d3bf570c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
From 1536b0a74f2fb213490c79375ba6accd5b6dc585 Mon Sep 17 00:00:00 2001
From: Lepton Wu <ytht.net@gmail.com>
Date: Fri, 12 Jan 2018 13:42:56 -0800
Subject: [PATCH 041/102] kaiser: Set _PAGE_NX only if supported

This finally resolve crash if loaded under qemu + haxm. Haitao Shan pointed
out that the reason of that crash is that NX bit get set for page tables.
It seems we missed checking if _PAGE_NX is supported in kaiser_add_user_map

Link: https://www.spinics.net/lists/kernel/msg2689835.html

Reviewed-by: Guenter Roeck <groeck@chromium.org>
Signed-off-by: Lepton Wu <ytht.net@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/x86/mm/kaiser.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/mm/kaiser.c b/arch/x86/mm/kaiser.c
index d8376b4..42a5307 100644
--- a/arch/x86/mm/kaiser.c
+++ b/arch/x86/mm/kaiser.c
@@ -184,6 +184,8 @@ static int kaiser_add_user_map(const void *__start_addr, unsigned long size,
 	 * requires that not to be #defined to 0): so mask it off here.
 	 */
 	flags &= ~_PAGE_GLOBAL;
+	if (!(__supported_pte_mask & _PAGE_NX))
+		flags &= ~_PAGE_NX;
 
 	for (; address < end_addr; address += PAGE_SIZE) {
 		target_address = get_pa_from_mapping(address);
-- 
2.7.4