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

Impact: BIOS proofing

"Glove box" off BIOS interrupts in the video code.

LKML-Reference: <49DE7F79.4030106@zytor.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Rafael J. Wysocki <rjw@sisk.pl>

1 files changed, 13 insertions, 14 deletions

diff --git a/arch/x86/boot/video-bios.c b/arch/x86/boot/video-bios.c
index 3fa979c9c363..d660be492363 100644
--- a/arch/x86/boot/video-bios.c
+++ b/arch/x86/boot/video-bios.c
@@ -2,6 +2,7 @@
  *
  *   Copyright (C) 1991, 1992 Linus Torvalds
  *   Copyright 2007 rPath, Inc. - All Rights Reserved
+ *   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.
@@ -29,21 +30,21 @@ static int bios_set_mode(struct mode_info *mi)
 
 static int set_bios_mode(u8 mode)
 {
-        u16 ax;
+        struct biosregs ireg, oreg;
         u8 new_mode;
 
-        ax = mode;              /* AH=0x00 Set Video Mode */
-        asm volatile(INT10
-                     : "+a" (ax)
-                     : : "ebx", "ecx", "edx", "esi", "edi");
+        initregs(&ireg);
+        ireg.al = mode;         /* AH=0x00 Set Video Mode */
+        intcall(0x10, &ireg, NULL);
 
-        ax = 0x0f00;            /* Get Current Video Mode */
-        asm volatile(INT10
-                     : "+a" (ax)
-                     : : "ebx", "ecx", "edx", "esi", "edi");
+
+        ireg.ah = 0x0f;         /* Get Current Video Mode */
+        intcall(0x10, &ireg, &oreg);
 
         do_restore = 1;         /* Assume video contents were lost */
-        new_mode = ax & 0x7f;   /* Not all BIOSes are clean with the top bit */
+
+        /* Not all BIOSes are clean with the top bit */
+        new_mode = ireg.al & 0x7f;
 
         if (new_mode == mode)
                 return 0;       /* Mode change OK */
@@ -53,10 +54,8 @@ static int set_bios_mode(u8 mode)
                 /* Mode setting failed, but we didn't end up where we
                    started.  That's bad.  Try to revert to the original
                    video mode. */
-                ax = boot_params.screen_info.orig_video_mode;
-                asm volatile(INT10
-                             : "+a" (ax)
-                             : : "ebx", "ecx", "edx", "esi", "edi");
+                ireg.ax = boot_params.screen_info.orig_video_mode;
+                intcall(0x10, &ireg, NULL);
         }
 #endif
         return -1;