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• boot/main.c (Аудиокод на Си)

/* -*- 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.
*
* ----------------------------------------------------------------------- */

/*
* 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)
{
struct biosregs ireg;
initregs(&ireg);
ireg.ax = 0x0305;
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&#

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