626073132b
The assembly header and initialization code, and the main() routine. main.c also contains some miscellaneous very short routines. Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
161 lines
3.8 KiB
C
161 lines
3.8 KiB
C
/* -*- linux-c -*- ------------------------------------------------------- *
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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* Copyright 2007 rPath, Inc. - All Rights Reserved
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*
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* This file is part of the Linux kernel, and is made available under
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* the terms of the GNU General Public License version 2.
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*
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* ----------------------------------------------------------------------- */
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/*
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* arch/i386/boot/main.c
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*
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* Main module for the real-mode kernel code
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*/
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#include "boot.h"
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struct boot_params boot_params __attribute__((aligned(16)));
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char *HEAP = _end;
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char *heap_end = _end; /* Default end of heap = no heap */
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/*
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* Copy the header into the boot parameter block. Since this
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* screws up the old-style command line protocol, adjust by
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* filling in the new-style command line pointer instead.
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*/
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#define OLD_CL_MAGIC 0xA33F
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#define OLD_CL_ADDRESS 0x20
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static void copy_boot_params(void)
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{
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struct old_cmdline {
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u16 cl_magic;
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u16 cl_offset;
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};
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const struct old_cmdline * const oldcmd =
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(const struct old_cmdline *)OLD_CL_ADDRESS;
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BUILD_BUG_ON(sizeof boot_params != 4096);
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memcpy(&boot_params.hdr, &hdr, sizeof hdr);
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if (!boot_params.hdr.cmd_line_ptr &&
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oldcmd->cl_magic == OLD_CL_MAGIC) {
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/* Old-style command line protocol. */
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u16 cmdline_seg;
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/* Figure out if the command line falls in the region
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of memory that an old kernel would have copied up
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to 0x90000... */
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if (oldcmd->cl_offset < boot_params.hdr.setup_move_size)
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cmdline_seg = ds();
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else
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cmdline_seg = 0x9000;
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boot_params.hdr.cmd_line_ptr =
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(cmdline_seg << 4) + oldcmd->cl_offset;
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}
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}
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/*
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* Set the keyboard repeat rate to maximum. Unclear why this
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* is done here; this might be possible to kill off as stale code.
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*/
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static void keyboard_set_repeat(void)
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{
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u16 ax = 0x0305;
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u16 bx = 0;
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asm volatile("int $0x16"
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: "+a" (ax), "+b" (bx)
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: : "ecx", "edx", "esi", "edi");
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}
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/*
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* Get Intel SpeedStep IST information.
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*/
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static void query_speedstep_ist(void)
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{
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asm("int $0x15"
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: "=a" (boot_params.speedstep_info[0]),
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"=b" (boot_params.speedstep_info[1]),
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"=c" (boot_params.speedstep_info[2]),
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"=d" (boot_params.speedstep_info[3])
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: "a" (0x0000e980), /* IST Support */
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"d" (0x47534943)); /* Request value */
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}
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/*
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* Tell the BIOS what CPU mode we intend to run in.
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*/
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static void set_bios_mode(void)
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{
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#ifdef CONFIG_X86_64
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u32 eax, ebx;
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eax = 0xec00;
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ebx = 2;
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asm volatile("int $0x15"
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: "+a" (eax), "+b" (ebx)
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: : "ecx", "edx", "esi", "edi");
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#endif
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}
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void main(void)
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{
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/* First, copy the boot header into the "zeropage" */
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copy_boot_params();
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/* End of heap check */
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if (boot_params.hdr.loadflags & CAN_USE_HEAP) {
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heap_end = (char *)(boot_params.hdr.heap_end_ptr
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+0x200-STACK_SIZE);
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} else {
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/* Boot protocol 2.00 only, no heap available */
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puts("WARNING: Ancient bootloader, some functionality "
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"may be limited!\n");
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}
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/* Make sure we have all the proper CPU support */
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if (validate_cpu()) {
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puts("Unable to boot - please use a kernel appropriate "
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"for your CPU.\n");
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die();
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}
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/* Tell the BIOS what CPU mode we intend to run in. */
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set_bios_mode();
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/* Detect memory layout */
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detect_memory();
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/* Set keyboard repeat rate (why?) */
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keyboard_set_repeat();
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/* Set the video mode */
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set_video();
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/* Query MCA information */
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query_mca();
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/* Voyager */
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#ifdef CONFIG_X86_VOYAGER
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query_voyager();
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#endif
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/* Query SpeedStep IST information */
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query_speedstep_ist();
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/* Query APM information */
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#if defined(CONFIG_APM) || defined(CONFIG_APM_MODULE)
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query_apm_bios();
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#endif
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/* Query EDD information */
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#if defined(CONFIG_EDD) || defined(CONFIG_EDD_MODULE)
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query_edd();
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#endif
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/* Do the last things and invoke protected mode */
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go_to_protected_mode();
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}
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