x86, setup: "glove box" BIOS interrupts in the core boot code

Impact: BIOS proofing

"Glove box" off BIOS interrupts in the core boot code.

LKML-Reference: <49DE7F79.4030106@zytor.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

1 files changed, 6 insertions, 3 deletions

diff --git a/arch/x86/boot/a20.c b/arch/x86/boot/a20.c
index 7c19ce8c244..64a31a6d751 100644
--- a/arch/x86/boot/a20.c
+++ b/arch/x86/boot/a20.c
@@ -2,7 +2,7 @@
  *
  *   Copyright (C) 1991, 1992 Linus Torvalds
  *   Copyright 2007-2008 rPath, Inc. - All Rights Reserved
- *   Copyright 2009 Intel Corporation
+ *   Copyright 2009 Intel Corporation; author H. Peter Anvin
  *
  *   This file is part of the Linux kernel, and is made available under
  *   the terms of the GNU General Public License version 2.
@@ -90,8 +90,11 @@ static int a20_test_long(void)
 
 static void enable_a20_bios(void)
 {
-        asm volatile("pushfl; int $0x15; popfl"
-                     : : "a" ((u16)0x2401));
+        struct biosregs ireg;
+
+        initregs(&ireg);
+        ireg.ax = 0x2401;
+        intcall(0x15, &ireg, NULL);
 }
 
 static void enable_a20_kbc(void)