182 lines
4.2 KiB
C
182 lines
4.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/* -*- linux-c -*- ------------------------------------------------------- *
|
|
*
|
|
* Copyright (C) 1991, 1992 Linus Torvalds
|
|
* Copyright 2007 rPath, Inc. - All Rights Reserved
|
|
* Copyright 2009 Intel Corporation; author H. Peter Anvin
|
|
*
|
|
* ----------------------------------------------------------------------- */
|
|
|
|
/*
|
|
* Main module for the real-mode kernel code
|
|
*/
|
|
#include <linux/build_bug.h>
|
|
|
|
#include "boot.h"
|
|
#include "string.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 =
|
|
absolute_pointer(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;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Query the keyboard lock status as given by the BIOS, and
|
|
* set the keyboard repeat rate to maximum. Unclear why the latter
|
|
* is done here; this might be possible to kill off as stale code.
|
|
*/
|
|
static void keyboard_init(void)
|
|
{
|
|
struct biosregs ireg, oreg;
|
|
initregs(&ireg);
|
|
|
|
ireg.ah = 0x02; /* Get keyboard status */
|
|
intcall(0x16, &ireg, &oreg);
|
|
boot_params.kbd_status = oreg.al;
|
|
|
|
ireg.ax = 0x0305; /* Set keyboard repeat rate */
|
|
intcall(0x16, &ireg, NULL);
|
|
}
|
|
|
|
/*
|
|
* Get Intel SpeedStep (IST) information.
|
|
*/
|
|
static void query_ist(void)
|
|
{
|
|
struct biosregs ireg, oreg;
|
|
|
|
/* 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;
|
|
|
|
initregs(&ireg);
|
|
ireg.ax = 0xe980; /* IST Support */
|
|
ireg.edx = 0x47534943; /* Request value */
|
|
intcall(0x15, &ireg, &oreg);
|
|
|
|
boot_params.ist_info.signature = oreg.eax;
|
|
boot_params.ist_info.command = oreg.ebx;
|
|
boot_params.ist_info.event = oreg.ecx;
|
|
boot_params.ist_info.perf_level = oreg.edx;
|
|
}
|
|
|
|
/*
|
|
* Tell the BIOS what CPU mode we intend to run in.
|
|
*/
|
|
static void set_bios_mode(void)
|
|
{
|
|
#ifdef CONFIG_X86_64
|
|
struct biosregs ireg;
|
|
|
|
initregs(&ireg);
|
|
ireg.ax = 0xec00;
|
|
ireg.bx = 2;
|
|
intcall(0x15, &ireg, NULL);
|
|
#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();
|
|
|
|
/* Initialize the early-boot console */
|
|
console_init();
|
|
if (cmdline_find_option_bool("debug"))
|
|
puts("early console in setup code\n");
|
|
|
|
/* 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?) and query the lock flags */
|
|
keyboard_init();
|
|
|
|
/* 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();
|
|
|
|
/* Do the last things and invoke protected mode */
|
|
go_to_protected_mode();
|
|
}
|