x86, setup: "glove box" BIOS interrupts in the core boot code
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>
diff --git a/arch/x86/boot/tty.c b/arch/x86/boot/tty.c
index 7e8e8b2..01ec69c 100644
--- a/arch/x86/boot/tty.c
+++ b/arch/x86/boot/tty.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.
@@ -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 @@
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 @@
*/
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)