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/* -*- linux-c -*- ------------------------------------------------------- *
*
* Copyright (C) 1991, 1992 Linus Torvalds
* Copyright 2007 rPath, Inc. - All Rights Reserved
*
* This file is part of the Linux kernel, and is made available under
* the terms of the GNU General Public License version 2.
*
* ----------------------------------------------------------------------- */
/*
* Main module for the real-mode kernel code
*/
#include "boot.h"
struct boot_params boot_params __attribute__((aligned(16)));
char *HEAP = _end;
char *heap_end = _end; /* Default end of heap = no heap */
/*
* Copy the header into the boot parameter block. Since this
* screws up the old-style command line protocol, adjust by
* filling in the new-style command line pointer instead.
*/
static void copy_boot_params(void)
{
struct old_cmdline {
u16 cl_magic;
u16 cl_offset;
};
const struct old_cmdline * const oldcmd =
(const struct old_cmdline *)OLD_CL_ADDRESS;
BUILD_BUG_ON(sizeof boot_params != 4096);
memcpy(&boot_params.hdr, &hdr, sizeof hdr);
if (!boot_params.hdr.cmd_line_ptr &&
oldcmd->cl_magic == OLD_CL_MAGIC) {
/* Old-style command line protocol. */
u16 cmdline_seg;
/* Figure out if the command line falls in the region
of memory that an old kernel would have copied up
to 0x90000... */
if (oldcmd->cl_offset < boot_params.hdr.setup_move_size)
cmdline_seg = ds();
else
cmdline_seg = 0x9000;
boot_params.hdr.cmd_line_ptr =
(cmdline_seg << 4) + oldcmd->cl_offset;
}
}
/*
* Set the keyboard repeat rate to maximum. Unclear why this
* is done here; this might be possible to kill off as stale code.
*/
static void keyboard_set_repeat(void)
{
u16 ax = 0x0305;
u16 bx = 0;
asm volatile("int $0x16"
: "+a" (ax), "+b" (bx)
: : "ecx", "edx", "esi", "edi");
}
/*
* Get Intel SpeedStep (IST) information.
*/
static void query_ist(void)
{
/* Some older BIOSes apparently crash on this call, so filter
it from machines too old to have SpeedStep at all. */
if (cpu.level < 6)
return;
asm("int $0x15"
: "=a" (boot_params.ist_info.signature),
"=b" (boot_params.ist_info.command),
"=c" (boot_params.ist_info.event),
"=d" (boot_params.ist_info.perf_level)
: "a" (0x0000e980), /* IST Support */
"d" (0x47534943)); /* Request value */
}
/*
* Tell the BIOS what CPU mode we intend to run in.
*/
static void set_bios_mode(void)
{
#ifdef CONFIG_X86_64
u32 eax, ebx;
eax = 0xec00;
ebx = 2;
asm volatile("int $0x15"
: "+a" (eax), "+b" (ebx)
: : "ecx", "edx", "esi", "edi");
#endif
}
static void init_heap(void)
{
char *stack_end;
if (boot_params.hdr.loadflags & CAN_USE_HEAP) {
asm("leal %P1(%%esp),%0"
: "=r" (stack_end) : "i" (-STACK_SIZE));
heap_end = (char *)
((size_t)boot_params.hdr.heap_end_ptr + 0x200);
if (heap_end > stack_end)
heap_end = stack_end;
} else {
/* Boot protocol 2.00 only, no heap available */
puts("WARNING: Ancient bootloader, some functionality "
"may be limited!\n");
}
}
void main(void)
{
/* First, copy the boot header into the "zeropage" */
copy_boot_params();
/* End of heap check */
init_heap();
/* Make sure we have all the proper CPU support */
if (validate_cpu()) {
puts("Unable to boot - please use a kernel appropriate "
"for your CPU.\n");
die();
}
/* Tell the BIOS what CPU mode we intend to run in. */
set_bios_mode();
/* Detect memory layout */
detect_memory();
/* Set keyboard repeat rate (why?) */
keyboard_set_repeat();
/* Query MCA information */
query_mca();
/* Query Intel SpeedStep (IST) information */
query_ist();
/* Query APM information */
#if defined(CONFIG_APM) || defined(CONFIG_APM_MODULE)
query_apm_bios();
#endif
/* Query EDD information */
#if defined(CONFIG_EDD) || defined(CONFIG_EDD_MODULE)
query_edd();
#endif
/* Set the video mode */
set_video();
/* Parse command line for 'quiet' and pass it to decompressor. */
if (cmdline_find_option_bool("quiet"))
boot_params.hdr.loadflags |= QUIET_FLAG;
/* Do the last things and invoke protected mode */
go_to_protected_mode();
}
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