178 lines
4.1 KiB
C
178 lines
4.1 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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* Copyright 2009 Intel Corporation; author H. Peter Anvin
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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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* 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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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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struct biosregs ireg;
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initregs(&ireg);
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ireg.ax = 0x0305;
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intcall(0x16, &ireg, NULL);
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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_ist(void)
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{
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struct biosregs ireg, oreg;
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/* Some older BIOSes apparently crash on this call, so filter
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it from machines too old to have SpeedStep at all. */
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if (cpu.level < 6)
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return;
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initregs(&ireg);
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ireg.ax = 0xe980; /* IST Support */
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ireg.edx = 0x47534943; /* Request value */
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intcall(0x15, &ireg, &oreg);
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boot_params.ist_info.signature = oreg.eax;
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boot_params.ist_info.command = oreg.ebx;
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boot_params.ist_info.event = oreg.ecx;
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boot_params.ist_info.perf_level = oreg.edx;
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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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struct biosregs ireg;
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initregs(&ireg);
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ireg.ax = 0xec00;
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ireg.bx = 2;
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intcall(0x15, &ireg, NULL);
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#endif
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}
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static void init_heap(void)
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{
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char *stack_end;
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if (boot_params.hdr.loadflags & CAN_USE_HEAP) {
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asm("leal %P1(%%esp),%0"
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: "=r" (stack_end) : "i" (-STACK_SIZE));
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heap_end = (char *)
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((size_t)boot_params.hdr.heap_end_ptr + 0x200);
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if (heap_end > stack_end)
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heap_end = stack_end;
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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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}
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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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init_heap();
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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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/* Query MCA information */
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query_mca();
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/* Query Intel SpeedStep (IST) information */
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query_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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/* Set the video mode */
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set_video();
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/* Parse command line for 'quiet' and pass it to decompressor. */
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if (cmdline_find_option_bool("quiet"))
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boot_params.hdr.loadflags |= QUIET_FLAG;
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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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