mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-11-26 20:20:53 +07:00
df7699c564
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>
115 lines
1.9 KiB
C
115 lines
1.9 KiB
C
/* -*- linux-c -*- ------------------------------------------------------- *
|
|
*
|
|
* 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.
|
|
*
|
|
* ----------------------------------------------------------------------- */
|
|
|
|
/*
|
|
* Very simple screen I/O
|
|
* XXX: Probably should add very simple serial I/O?
|
|
*/
|
|
|
|
#include "boot.h"
|
|
|
|
/*
|
|
* These functions are in .inittext so they can be used to signal
|
|
* error during initialization.
|
|
*/
|
|
|
|
void __attribute__((section(".inittext"))) putchar(int ch)
|
|
{
|
|
struct biosregs ireg;
|
|
|
|
if (ch == '\n')
|
|
putchar('\r'); /* \n -> \r\n */
|
|
|
|
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)
|
|
{
|
|
while (*str)
|
|
putchar(*str++);
|
|
}
|
|
|
|
/*
|
|
* Read the CMOS clock through the BIOS, and return the
|
|
* seconds in BCD.
|
|
*/
|
|
|
|
static u8 gettime(void)
|
|
{
|
|
struct biosregs ireg, oreg;
|
|
|
|
initregs(&ireg);
|
|
ireg.ah = 0x02;
|
|
intcall(0x1a, &ireg, &oreg);
|
|
|
|
return oreg.dh;
|
|
}
|
|
|
|
/*
|
|
* Read from the keyboard
|
|
*/
|
|
int getchar(void)
|
|
{
|
|
struct biosregs ireg, oreg;
|
|
|
|
initregs(&ireg);
|
|
/* ireg.ah = 0x00; */
|
|
intcall(0x16, &ireg, &oreg);
|
|
|
|
return oreg.al;
|
|
}
|
|
|
|
static int kbd_pending(void)
|
|
{
|
|
struct biosregs ireg, oreg;
|
|
|
|
initregs(&ireg);
|
|
ireg.ah = 0x01;
|
|
intcall(0x16, &ireg, &oreg);
|
|
|
|
return !(oreg.eflags & X86_EFLAGS_ZF);
|
|
}
|
|
|
|
void kbd_flush(void)
|
|
{
|
|
for (;;) {
|
|
if (!kbd_pending())
|
|
break;
|
|
getchar();
|
|
}
|
|
}
|
|
|
|
int getchar_timeout(void)
|
|
{
|
|
int cnt = 30;
|
|
int t0, t1;
|
|
|
|
t0 = gettime();
|
|
|
|
while (cnt) {
|
|
if (kbd_pending())
|
|
return getchar();
|
|
|
|
t1 = gettime();
|
|
if (t0 != t1) {
|
|
cnt--;
|
|
t0 = t1;
|
|
}
|
|
}
|
|
|
|
return 0; /* Timeout! */
|
|
}
|