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

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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>
This commit is contained in:
H. Peter Anvin
2009-04-01 18:13:46 -07:00
committed by H. Peter Anvin
parent 7a734e7dd9
commit df7699c564
4 changed files with 95 additions and 86 deletions
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52
arch/x86/boot/tty.c
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@@ -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.
@@ -22,24 +23,23 @@
void __attribute__((section(".inittext"))) putchar(int ch)
{
unsigned char c = ch;
struct biosregs ireg;
if (c == '\n')
if (ch == '\n')
putchar('\r'); /* \n -> \r\n */
/* int $0x10 is known to have bugs involving touching registers
it shouldn't. Be extra conservative... */
asm volatile("pushal; pushw %%ds; int $0x10; popw %%ds; popal"
: : "b" (0x0007), "c" (0x0001), "a" (0x0e00|ch));
initregs(&ireg);
ireg.bx = 0x0007;
ireg.cx = 0x0001;
ireg.ah = 0x0e;
ireg.al = ch;
intcall(0x10, &ireg, NULL);
}
void __attribute__((section(".inittext"))) puts(const char *str)
{
int n = 0;
while (*str) {
while (*str)
putchar(*str++);
n++;
}
}
/*
@@ -49,14 +49,13 @@ void __attribute__((section(".inittext"))) puts(const char *str)
static u8 gettime(void)
{
u16 ax = 0x0200;
u16 cx, dx;
struct biosregs ireg, oreg;
asm volatile("int $0x1a"
: "+a" (ax), "=c" (cx), "=d" (dx)
: : "ebx", "esi", "edi");
initregs(&ireg);
ireg.ah = 0x02;
intcall(0x1a, &ireg, &oreg);
return dx >> 8;
return oreg.dh;
}
/*
@@ -64,19 +63,24 @@ static u8 gettime(void)
*/
int getchar(void)
{
u16 ax = 0;
asm volatile("int $0x16" : "+a" (ax));
struct biosregs ireg, oreg;
return ax & 0xff;
initregs(&ireg);
/* ireg.ah = 0x00; */
intcall(0x16, &ireg, &oreg);
return oreg.al;
}
static int kbd_pending(void)
{
u8 pending;
asm volatile("int $0x16; setnz %0"
: "=qm" (pending)
: "a" (0x0100));
return pending;
struct biosregs ireg, oreg;
initregs(&ireg);
ireg.ah = 0x01;
intcall(0x16, &ireg, &oreg);
return !(oreg.eflags & X86_EFLAGS_ZF);
}
void kbd_flush(void)