From ec61bafb2abd42a148d41143570732052a577fc0 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] 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 8f8e5e03d083..a8ade08a9bf5 100644
--- a/arch/x86/mm/kaiser.c
+++ b/arch/x86/mm/kaiser.c
@@ -197,6 +197,8 @@ 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);