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, 59 insertions, 36 deletions

diff --git a/arch/x86/boot/video-vga.c b/arch/x86/boot/video-vga.c
index 9e0587a37768..8f8d827e254d 100644
--- a/arch/x86/boot/video-vga.c
+++ b/arch/x86/boot/video-vga.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.
@@ -39,30 +40,30 @@ static __videocard video_vga;
 /* Set basic 80x25 mode */
 static u8 vga_set_basic_mode(void)
 {
+        struct biosregs ireg, oreg;
         u16 ax;
         u8 rows;
         u8 mode;
 
+        initregs(&ireg);
+
 #ifdef CONFIG_VIDEO_400_HACK
         if (adapter >= ADAPTER_VGA) {
-                asm volatile(INT10
-                             : : "a" (0x1202), "b" (0x0030)
-                             : "ecx", "edx", "esi", "edi");
+                ireg.ax = 0x1202;
+                ireg.bx = 0x0030;
+                intcall(0x10, &ireg, NULL);
         }
 #endif
 
         ax = 0x0f00;
-        asm volatile(INT10
-                     : "+a" (ax)
-                     : : "ebx", "ecx", "edx", "esi", "edi");
-
-        mode = (u8)ax;
+        intcall(0x10, &ireg, &oreg);
+        mode = oreg.al;
 
         set_fs(0);
         rows = rdfs8(0x484);    /* rows minus one */
 
 #ifndef CONFIG_VIDEO_400_HACK
-        if ((ax == 0x5003 || ax == 0x5007) &&
+        if ((oreg.ax == 0x5003 || oreg.ax == 0x5007) &&
             (rows == 0 || rows == 24))
                 return mode;
 #endif
@@ -71,10 +72,8 @@ static u8 vga_set_basic_mode(void)
                 mode = 3;
 
         /* Set the mode */
-        ax = mode;
-        asm volatile(INT10
-                     : "+a" (ax)
-                     : : "ebx", "ecx", "edx", "esi", "edi");
+        ireg.ax = mode;         /* AH=0: set mode */
+        intcall(0x10, &ireg, NULL);
         do_restore = 1;
         return mode;
 }
@@ -82,43 +81,69 @@ static u8 vga_set_basic_mode(void)
 static void vga_set_8font(void)
 {
         /* Set 8x8 font - 80x43 on EGA, 80x50 on VGA */
+        struct biosregs ireg;
+
+        initregs(&ireg);
 
         /* Set 8x8 font */
-        asm volatile(INT10 : : "a" (0x1112), "b" (0));
+        ireg.ax = 0x1112;
+        /* ireg.bl = 0; */
+        intcall(0x10, &ireg, NULL);
 
         /* Use alternate print screen */
-        asm volatile(INT10 : : "a" (0x1200), "b" (0x20));
+        ireg.ax = 0x1200;
+        ireg.bl = 0x20;
+        intcall(0x10, &ireg, NULL);
 
         /* Turn off cursor emulation */
-        asm volatile(INT10 : : "a" (0x1201), "b" (0x34));
+        ireg.ax = 0x1201;
+        ireg.bl = 0x34;
+        intcall(0x10, &ireg, NULL);
 
         /* Cursor is scan lines 6-7 */
-        asm volatile(INT10 : : "a" (0x0100), "c" (0x0607));
+        ireg.ax = 0x0100;
+        ireg.cx = 0x0607;
+        intcall(0x10, &ireg, NULL);
 }
 
 static void vga_set_14font(void)
 {
         /* Set 9x14 font - 80x28 on VGA */
+        struct biosregs ireg;
+
+        initregs(&ireg);
 
         /* Set 9x14 font */
-        asm volatile(INT10 : : "a" (0x1111), "b" (0));
+        ireg.ax = 0x1111;
+        /* ireg.bl = 0; */
+        intcall(0x10, &ireg, NULL);
 
         /* Turn off cursor emulation */
-        asm volatile(INT10 : : "a" (0x1201), "b" (0x34));
+        ireg.ax = 0x1201;
+        ireg.bl = 0x34;
+        intcall(0x10, &ireg, NULL);
 
         /* Cursor is scan lines 11-12 */
-        asm volatile(INT10 : : "a" (0x0100), "c" (0x0b0c));
+        ireg.ax = 0x0100;
+        ireg.cx = 0x0b0c;
+        intcall(0x10, &ireg, NULL);
 }
 
 static void vga_set_80x43(void)
 {
         /* Set 80x43 mode on VGA (not EGA) */
+        struct biosregs ireg;
+
+        initregs(&ireg);
 
         /* Set 350 scans */
-        asm volatile(INT10 : : "a" (0x1201), "b" (0x30));
+        ireg.ax = 0x1201;
+        ireg.bl = 0x30;
+        intcall(0x10, &ireg, NULL);
 
         /* Reset video mode */
-        asm volatile(INT10 : : "a" (0x0003));
+        ireg.ax = 0x0003;
+        intcall(0x10, &ireg, NULL);
 
         vga_set_8font();
 }
@@ -225,8 +250,6 @@ static int vga_set_mode(struct mode_info *mode)
  */
 static int vga_probe(void)
 {
-        u16 ega_bx;
-
         static const char *card_name[] = {
                 "CGA/MDA/HGC", "EGA", "VGA"
         };
@@ -240,26 +263,26 @@ static int vga_probe(void)
                 sizeof(ega_modes)/sizeof(struct mode_info),
                 sizeof(vga_modes)/sizeof(struct mode_info),
         };
-        u8 vga_flag;
 
-        asm(INT10
-            : "=b" (ega_bx)
-            : "a" (0x1200), "b" (0x10) /* Check EGA/VGA */
-            : "ecx", "edx", "esi", "edi");
+        struct biosregs ireg, oreg;
+
+        initregs(&ireg);
+
+        ireg.ax = 0x1200;
+        ireg.bl = 0x10;         /* Check EGA/VGA */
+        intcall(0x10, &ireg, &oreg);
 
 #ifndef _WAKEUP
-        boot_params.screen_info.orig_video_ega_bx = ega_bx;
+        boot_params.screen_info.orig_video_ega_bx = oreg.bx;
 #endif
 
         /* If we have MDA/CGA/HGC then BL will be unchanged at 0x10 */
-        if ((u8)ega_bx != 0x10) {
+        if (oreg.bl != 0x10) {
                 /* EGA/VGA */
-                asm(INT10
-                    : "=a" (vga_flag)
-                    : "a" (0x1a00)
-                    : "ebx", "ecx", "edx", "esi", "edi");
+                ireg.ax = 0x1a00;
+                intcall(0x10, &ireg, &oreg);
 
-                if (vga_flag == 0x1a) {
+                if (oreg.al == 0x1a) {
                         adapter = ADAPTER_VGA;
 #ifndef _WAKEUP
                         boot_params.screen_info.orig_video_isVGA = 1;