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, 60 insertions, 77 deletions

diff --git a/arch/x86/boot/video-vesa.c b/arch/x86/boot/video-vesa.c
index 4a58c8ce3f69..c700147d6ffb 100644
--- a/arch/x86/boot/video-vesa.c
+++ b/arch/x86/boot/video-vesa.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.
@@ -31,7 +32,7 @@ static inline void vesa_store_mode_params_graphics(void) {}
 static int vesa_probe(void)
 {
 #if defined(CONFIG_VIDEO_VESA) || defined(CONFIG_FIRMWARE_EDID)
-        u16 ax, cx, di;
+        struct biosregs ireg, oreg;
         u16 mode;
         addr_t mode_ptr;
         struct mode_info *mi;
@@ -39,13 +40,12 @@ static int vesa_probe(void)
 
         video_vesa.modes = GET_HEAP(struct mode_info, 0);
 
-        ax = 0x4f00;
-        di = (size_t)&vginfo;
-        asm(INT10
-            : "+a" (ax), "+D" (di), "=m" (vginfo)
-            : : "ebx", "ecx", "edx", "esi");
+        initregs(&ireg);
+        ireg.ax = 0x4f00;
+        ireg.di = (size_t)&vginfo;
+        intcall(0x10, &ireg, &oreg);
 
-        if (ax != 0x004f ||
+        if (ireg.ax != 0x004f ||
             vginfo.signature != VESA_MAGIC ||
             vginfo.version < 0x0102)
                 return 0;       /* Not present */
@@ -65,14 +65,12 @@ static int vesa_probe(void)
 
                 memset(&vminfo, 0, sizeof vminfo); /* Just in case... */
 
-                ax = 0x4f01;
-                cx = mode;
-                di = (size_t)&vminfo;
-                asm(INT10
-                    : "+a" (ax), "+c" (cx), "+D" (di), "=m" (vminfo)
-                    : : "ebx", "edx", "esi");
+                ireg.ax = 0x4f01;
+                ireg.cx = mode;
+                ireg.di = (size_t)&vminfo;
+                intcall(0x10, &ireg, &oreg);
 
-                if (ax != 0x004f)
+                if (ireg.ax != 0x004f)
                         continue;
 
                 if ((vminfo.mode_attr & 0x15) == 0x05) {
@@ -111,20 +109,19 @@ static int vesa_probe(void)
 
 static int vesa_set_mode(struct mode_info *mode)
 {
-        u16 ax, bx, cx, di;
+        struct biosregs ireg, oreg;
         int is_graphic;
         u16 vesa_mode = mode->mode - VIDEO_FIRST_VESA;
 
         memset(&vminfo, 0, sizeof vminfo); /* Just in case... */
 
-        ax = 0x4f01;
-        cx = vesa_mode;
-        di = (size_t)&vminfo;
-        asm(INT10
-            : "+a" (ax), "+c" (cx), "+D" (di), "=m" (vminfo)
-            : : "ebx", "edx", "esi");
+        initregs(&ireg);
+        ireg.ax = 0x4f01;
+        ireg.cx = vesa_mode;
+        ireg.di = (size_t)&vminfo;
+        intcall(0x10, &ireg, &oreg);
 
-        if (ax != 0x004f)
+        if (oreg.ax != 0x004f)
                 return -1;
 
         if ((vminfo.mode_attr & 0x15) == 0x05) {
@@ -141,14 +138,12 @@ static int vesa_set_mode(struct mode_info *mode)
         }
 
 
-        ax = 0x4f02;
-        bx = vesa_mode;
-        di = 0;
-        asm volatile(INT10
-                     : "+a" (ax), "+b" (bx), "+D" (di)
-                     : : "ecx", "edx", "esi");
+        initregs(&ireg);
+        ireg.ax = 0x4f02;
+        ireg.bx = vesa_mode;
+        intcall(0x10, &ireg, &oreg);
 
-        if (ax != 0x004f)
+        if (oreg.ax != 0x004f)
                 return -1;
 
         graphic_mode = is_graphic;
@@ -171,50 +166,45 @@ static int vesa_set_mode(struct mode_info *mode)
 /* Switch DAC to 8-bit mode */
 static void vesa_dac_set_8bits(void)
 {
+        struct biosregs ireg, oreg;
         u8 dac_size = 6;
 
         /* If possible, switch the DAC to 8-bit mode */
         if (vginfo.capabilities & 1) {
-                u16 ax, bx;
-
-                ax = 0x4f08;
-                bx = 0x0800;
-                asm volatile(INT10
-                             : "+a" (ax), "+b" (bx)
-                             : : "ecx", "edx", "esi", "edi");
-
-                if (ax == 0x004f)
-                        dac_size = bx >> 8;
+                initregs(&ireg);
+                ireg.ax = 0x4f08;
+                ireg.bh = 0x08;
+                intcall(0x10, &ireg, &oreg);
+                if (oreg.ax == 0x004f)
+                        dac_size = oreg.bh;
         }
 
         /* Set the color sizes to the DAC size, and offsets to 0 */
-        boot_params.screen_info.red_size = dac_size;
+        boot_params.screen_info.red_size   = dac_size;
         boot_params.screen_info.green_size = dac_size;
-        boot_params.screen_info.blue_size = dac_size;
-        boot_params.screen_info.rsvd_size = dac_size;
+        boot_params.screen_info.blue_size  = dac_size;
+        boot_params.screen_info.rsvd_size  = dac_size;
 
-        boot_params.screen_info.red_pos = 0;
-        boot_params.screen_info.green_pos = 0;
-        boot_params.screen_info.blue_pos = 0;
-        boot_params.screen_info.rsvd_pos = 0;
+        boot_params.screen_info.red_pos    = 0;
+        boot_params.screen_info.green_pos  = 0;
+        boot_params.screen_info.blue_pos   = 0;
+        boot_params.screen_info.rsvd_pos   = 0;
 }
 
 /* Save the VESA protected mode info */
 static void vesa_store_pm_info(void)
 {
-        u16 ax, bx, di, es;
+        struct biosregs ireg, oreg;
 
-        ax = 0x4f0a;
-        bx = di = 0;
-        asm("pushw %%es; "INT10"; movw %%es,%0; popw %%es"
-            : "=d" (es), "+a" (ax), "+b" (bx), "+D" (di)
-            : : "ecx", "esi");
+        initregs(&ireg);
+        ireg.ax = 0x4f0a;
+        intcall(0x10, &ireg, &oreg);
 
-        if (ax != 0x004f)
+        if (oreg.ax != 0x004f)
                 return;
 
-        boot_params.screen_info.vesapm_seg = es;
-        boot_params.screen_info.vesapm_off = di;
+        boot_params.screen_info.vesapm_seg = oreg.es;
+        boot_params.screen_info.vesapm_off = oreg.di;
 }
 
 /*
@@ -252,7 +242,7 @@ static void vesa_store_mode_params_graphics(void)
 void vesa_store_edid(void)
 {
 #ifdef CONFIG_FIRMWARE_EDID
-        u16 ax, bx, cx, dx, di;
+        struct biosregs ireg, oreg;
 
         /* Apparently used as a nonsense token... */
         memset(&boot_params.edid_info, 0x13, sizeof boot_params.edid_info);
@@ -260,33 +250,26 @@ void vesa_store_edid(void)
         if (vginfo.version < 0x0200)
                 return;         /* EDID requires VBE 2.0+ */
 
-        ax = 0x4f15;            /* VBE DDC */
-        bx = 0x0000;            /* Report DDC capabilities */
-        cx = 0;                 /* Controller 0 */
-        di = 0;                 /* ES:DI must be 0 by spec */
-
-        /* Note: The VBE DDC spec is different from the main VESA spec;
-           we genuinely have to assume all registers are destroyed here. */
-
-        asm("pushw %%es; movw %2,%%es; "INT10"; popw %%es"
-            : "+a" (ax), "+b" (bx), "+c" (cx), "+D" (di)
-            : : "esi", "edx");
+        initregs(&ireg);
+        ireg.ax = 0x4f15;               /* VBE DDC */
+        /* ireg.bx = 0x0000; */         /* Report DDC capabilities */
+        /* ireg.cx = 0; */              /* Controller 0 */
+        ireg.es = 0;                    /* ES:DI must be 0 by spec */
+        intcall(0x10, &ireg, &oreg);
 
-        if (ax != 0x004f)
+        if (oreg.ax != 0x004f)
                 return;         /* No EDID */
 
         /* BH = time in seconds to transfer EDD information */
         /* BL = DDC level supported */
 
-        ax = 0x4f15;            /* VBE DDC */
-        bx = 0x0001;            /* Read EDID */
-        cx = 0;                 /* Controller 0 */
-        dx = 0;                 /* EDID block number */
-        di =(size_t) &boot_params.edid_info; /* (ES:)Pointer to block */
-        asm(INT10
-            : "+a" (ax), "+b" (bx), "+d" (dx), "=m" (boot_params.edid_info),
-              "+c" (cx), "+D" (di)
-            : : "esi");
+        ireg.ax = 0x4f15;               /* VBE DDC */
+        ireg.bx = 0x0001;               /* Read EDID */
+        /* ireg.cx = 0; */              /* Controller 0 */
+        /* ireg.dx = 0; */              /* EDID block number */
+        ireg.es = ds();
+        ireg.di =(size_t)&boot_params.edid_info; /* (ES:)Pointer to block */
+        intcall(0x10, &ireg, &oreg);
 #endif /* CONFIG_FIRMWARE_EDID */
 }