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, 19 insertions, 23 deletions

diff --git a/arch/x86/boot/video.c b/arch/x86/boot/video.c
index 3bef2c1febe9..bad728b76fc2 100644
--- a/arch/x86/boot/video.c
+++ b/arch/x86/boot/video.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.
@@ -18,33 +19,29 @@
 
 static void store_cursor_position(void)
 {
-        u16 curpos;
-        u16 ax, bx;
+        struct biosregs ireg, oreg;
 
-        ax = 0x0300;
-        bx = 0;
-        asm(INT10
-            : "=d" (curpos), "+a" (ax), "+b" (bx)
-            : : "ecx", "esi", "edi");
+        initregs(&ireg);
+        ireg.ah = 0x03;
+        intcall(0x10, &ireg, &oreg);
 
-        boot_params.screen_info.orig_x = curpos;
-        boot_params.screen_info.orig_y = curpos >> 8;
+        boot_params.screen_info.orig_x = oreg.dl;
+        boot_params.screen_info.orig_y = oreg.dh;
 }
 
 static void store_video_mode(void)
 {
-        u16 ax, page;
+        struct biosregs ireg, oreg;
 
         /* N.B.: the saving of the video page here is a bit silly,
            since we pretty much assume page 0 everywhere. */
-        ax = 0x0f00;
-        asm(INT10
-            : "+a" (ax), "=b" (page)
-            : : "ecx", "edx", "esi", "edi");
+        initregs(&ireg);
+        ireg.ah = 0x0f;
+        intcall(0x10, &ireg, &oreg);
 
         /* Not all BIOSes are clean with respect to the top bit */
-        boot_params.screen_info.orig_video_mode = ax & 0x7f;
-        boot_params.screen_info.orig_video_page = page >> 8;
+        boot_params.screen_info.orig_video_mode = oreg.al & 0x7f;
+        boot_params.screen_info.orig_video_page = oreg.bh;
 }
 
 /*
@@ -257,7 +254,7 @@ static void restore_screen(void)
         int y;
         addr_t dst = 0;
         u16 *src = saved.data;
-        u16 ax, bx, dx;
+        struct biosregs ireg;
 
         if (graphic_mode)
                 return;         /* Can't restore onto a graphic mode */
@@ -296,12 +293,11 @@ static void restore_screen(void)
         }
 
         /* Restore cursor position */
-        ax = 0x0200;            /* Set cursor position */
-        bx = 0;                 /* Page number (<< 8) */
-        dx = (saved.cury << 8)+saved.curx;
-        asm volatile(INT10
-                     : "+a" (ax), "+b" (bx), "+d" (dx)
-                     : : "ecx", "esi", "edi");
+        initregs(&ireg);
+        ireg.ah = 0x02;         /* Set cursor position */
+        ireg.dh = saved.cury;
+        ireg.dl = saved.curx;
+        intcall(0x10, &ireg, NULL);
 }
 #else
 #define save_screen()           ((void)0)