asmstub.c

i386的bootloader源码grub

/* asmstub.c - a version of shared_src/asm.S that works under Unix */
/*
 *  GRUB  --  GRand Unified Bootloader
 *  Copyright (C) 1999,2000,2001,2002,2004  Free Software Foundation, Inc.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

/* Try to use glibc's transparant LFS support. */
#define _LARGEFILE_SOURCE	1
/* lseek becomes synonymous with lseek64.  */
#define _FILE_OFFSET_BITS	64

/* Simulator entry point. */
int grub_stage2 (void);

#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <assert.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <time.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <setjmp.h>
#include <sys/time.h>
#include <termios.h>
#include <signal.h>

#ifdef __linux__
# include <sys/ioctl.h>		/* ioctl */
# if !defined(__GLIBC__) || \
	((__GLIBC__ < 2) || ((__GLIBC__ == 2) && (__GLIBC_MINOR__ < 1)))
/* Maybe libc doesn't have large file support.  */
#  include <linux/unistd.h>	/* _llseek */
# endif /* (GLIBC < 2) || ((__GLIBC__ == 2) && (__GLIBC_MINOR < 1)) */
# ifndef BLKFLSBUF
#  define BLKFLSBUF	_IO (0x12,97)	/* flush buffer cache */
# endif /* ! BLKFLSBUF */
#endif /* __linux__ */

/* We want to prevent any circularararity in our stubs, as well as
   libc name clashes. */
#define WITHOUT_LIBC_STUBS 1
#include <shared.h>
#include <device.h>
#include <serial.h>
#include <term.h>

/* Simulated memory sizes. */
#define EXTENDED_MEMSIZE (3 * 1024 * 1024)	/* 3MB */
#define CONVENTIONAL_MEMSIZE (640 * 1024)	/* 640kB */

unsigned long install_partition = 0x20000;
unsigned long boot_drive = 0;
int saved_entryno = 0;
char version_string[] = VERSION;
char config_file[128] = "/boot/grub/menu.lst"; /* FIXME: arbitrary */
unsigned long linux_text_len = 0;
char *linux_data_tmp_addr = 0;
char *linux_data_real_addr = 0;
unsigned short io_map[IO_MAP_SIZE];
struct apm_info apm_bios_info;

/* Emulation requirements. */
char *grub_scratch_mem = 0;

struct geometry *disks = 0;

/* The map between BIOS drives and UNIX device file names.  */
char **device_map = 0;

/* The jump buffer for exiting correctly.  */
static jmp_buf env_for_exit;

/* The current color for console.  */
static int console_current_color = A_NORMAL;

/* The file descriptor for a serial device.  */
static int serial_fd = -1;

/* The file name of a serial device.  */
static char *serial_device = 0;

#ifdef SIMULATE_SLOWNESS_OF_SERIAL
/* The speed of a serial device.  */
static unsigned int serial_speed;
#endif /* SIMULATE_SLOWNESS_OF_SERIAL */

/* The main entry point into this mess. */
int
grub_stage2 (void)
{
  /* These need to be static, because they survive our stack transitions. */
  static int status = 0;
  static char *realstack;
  char *scratch, *simstack;
  int i;

  /* We need a nested function so that we get a clean stack frame,
     regardless of how the code is optimized. */
  static volatile void doit ()
  {
    /* Make sure our stack lives in the simulated memory area. */
    asm volatile ("movl %%esp, %0\n\tmovl %1, %%esp\n"
		  : "=&r" (realstack) : "r" (simstack));

    /* Do a setjmp here for the stop command.  */
    if (! setjmp (env_for_exit))
      {
	/* Actually enter the generic stage2 code.  */
	status = 0;
	init_bios_info ();
      }
    else
      {
	/* If ERRNUM is non-zero, then set STATUS to non-zero.  */
	if (errnum)
	  status = 1;
      }

    /* Replace our stack before we use any local variables. */
    asm volatile ("movl %0, %%esp\n" : : "r" (realstack));
  }

  assert (grub_scratch_mem == 0);
  scratch = malloc (0x100000 + EXTENDED_MEMSIZE + 15);
  assert (scratch);
  grub_scratch_mem = (char *) ((((int) scratch) >> 4) << 4);

  /* FIXME: simulate the memory holes using mprot, if available. */

  assert (disks == 0);
  disks = malloc (NUM_DISKS * sizeof (*disks));
  assert (disks);
  /* Initialize DISKS.  */
  for (i = 0; i < NUM_DISKS; i++)
    disks[i].flags = -1;

  if (! init_device_map (&device_map, device_map_file, floppy_disks))
    return 1;
  
  /* Check some invariants. */
  assert ((SCRATCHSEG << 4) == SCRATCHADDR);
  assert ((BUFFERSEG << 4) == BUFFERADDR);
  assert (BUFFERADDR + BUFFERLEN == SCRATCHADDR);
  assert (FSYS_BUF % 16 == 0);
  assert (FSYS_BUF + FSYS_BUFLEN == BUFFERADDR);

#ifdef HAVE_LIBCURSES
  /* Get into char-at-a-time mode. */
  if (use_curses)
    {
      initscr ();
      cbreak ();
      noecho ();
      nonl ();
      scrollok (stdscr, TRUE);
      keypad (stdscr, TRUE);
      wtimeout (stdscr, 100);
      signal (SIGWINCH, SIG_IGN);
    }
#endif

  /* Make sure that actual writing is done.  */
  sync ();

  /* Set our stack, and go for it. */
  simstack = (char *) PROTSTACKINIT;
  doit ();

  /* I don't know if this is necessary really.  */
  sync ();

#ifdef HAVE_LIBCURSES
  if (use_curses)
    endwin ();
#endif

  /* Close off the file descriptors we used. */
  for (i = 0; i < NUM_DISKS; i ++)
    if (disks[i].flags != -1)
      {
#ifdef __linux__
	/* In Linux, invalidate the buffer cache. In other OSes, reboot
	   is one of the solutions...  */
	ioctl (disks[i].flags, BLKFLSBUF, 0);
#else
# warning "In your operating system, the buffer cache will not be flushed."
#endif
	close (disks[i].flags);
      }

  if (serial_fd >= 0)
    close (serial_fd);
  
  /* Release memory. */
  restore_device_map (device_map);
  device_map = 0;
  free (disks);
  disks = 0;
  free (scratch);
  grub_scratch_mem = 0;

  if (serial_device)
    free (serial_device);
  serial_device = 0;
  
  /* Ahh... at last we're ready to return to caller. */
  return status;
}

/* Assign DRIVE to a device name DEVICE.  */
void
assign_device_name (int drive, const char *device)
{
  /* If DRIVE is already assigned, free it.  */
  if (device_map[drive])
    free (device_map[drive]);

  /* If the old one is already opened, close it.  */
  if (disks[drive].flags != -1)
    {
      close (disks[drive].flags);
      disks[drive].flags = -1;
    }

  /* Assign DRIVE to DEVICE.  */
  if (! device)
    device_map[drive] = 0;
  else
    device_map[drive] = strdup (device);
}

void
stop (void)
{
#ifdef HAVE_LIBCURSES
  if (use_curses)
    endwin ();
#endif

  /* Jump to doit.  */
  longjmp (env_for_exit, 1);
}

void
grub_reboot (void)
{
  stop ();
}

void
grub_halt (int no_apm)
{
  stop ();
}

/* calls for direct boot-loader chaining */
void
chain_stage1 (unsigned long segment, unsigned long offset,
	      unsigned long part_table_addr)
{
  stop ();
}


void
chain_stage2 (unsigned long segment, unsigned long offset, int second_sector)
{
  stop ();
}


/* do some funky stuff, then boot linux */
void
linux_boot (void)
{
  stop ();
}


/* For bzImage kernels. */
void
big_linux_boot (void)
{
  stop ();
}


/* booting a multiboot executable */
void
multi_boot (int start, int mb_info)
{
  stop ();
}

/* sets it to linear or wired A20 operation */
void
gateA20 (int linear)
{
  /* Nothing to do in the simulator. */
}

/* Set up the int15 handler.  */
void
set_int15_handler (void)
{
  /* Nothing to do in the simulator.  */
}

/* Restore the original int15 handler.  */
void
unset_int15_handler (void)
{
  /* Nothing to do in the simulator.  */
}

/* The key map.  */
unsigned short bios_key_map[KEY_MAP_SIZE + 1];
unsigned short ascii_key_map[KEY_MAP_SIZE + 1];

/* Copy MAP to the drive map and set up the int13 handler.  */
void
set_int13_handler (unsigned short *map)
{
  /* Nothing to do in the simulator.  */
}

int
get_code_end (void)
{
  /* Just return a little area for simulation. */
  return BOOTSEC_LOCATION + (60 * 1024);
}


/* memory probe routines */
int
get_memsize (int type)
{
  if (! type)
    return CONVENTIONAL_MEMSIZE >> 10;
  else
    return EXTENDED_MEMSIZE >> 10;
}


/* get_eisamemsize() :  return packed EISA memory map, lower 16 bits is
 *		memory between 1M and 16M in 1K parts, upper 16 bits is
 *		memory above 16M in 64K parts.  If error, return -1.
 */
int
get_eisamemsize (void)
{
  return (EXTENDED_MEMSIZE >> 10);
}


#define MMAR_DESC_TYPE_AVAILABLE 1 /* available to OS */
#define MMAR_DESC_TYPE_RESERVED 2 /* not available */
#define MMAR_DESC_TYPE_ACPI_RECLAIM 3 /* usable by OS after reading ACPI */
#define MMAR_DESC_TYPE_ACPI_NVS 4 /* required to save between NVS sessions */

#define MMAR_DESC_LENGTH	20

/* Fetch the next entry in the memory map and return the continuation
   value.  DESC is a pointer to the descriptor buffer, and CONT is the
   previous continuation value (0 to get the first entry in the
   map).  */
int
get_mmap_entry (struct mmar_desc *desc, int cont)
{
  /* Record the memory map statically.  */
  static struct mmar_desc desc_table[] =
  {
    /* The conventional memory.  */
    {
      MMAR_DESC_LENGTH,
      0,
      CONVENTIONAL_MEMSIZE,
      MMAR_DESC_TYPE_AVAILABLE
    },
    /* BIOS RAM and ROM (such as video memory).  */
    {
      MMAR_DESC_LENGTH,
      CONVENTIONAL_MEMSIZE,
      0x100000 - CONVENTIONAL_MEMSIZE,
      MMAR_DESC_TYPE_RESERVED
    },
    /* The extended memory.  */
    {
      MMAR_DESC_LENGTH,
      0x100000,
      EXTENDED_MEMSIZE,
      MMAR_DESC_TYPE_AVAILABLE
    }
  };
  
  int num = sizeof (desc_table) / sizeof (*desc_table);

  if (cont < 0 || cont >= num)
    {
      /* Should not happen.  */
      desc->desc_len = 0;
    }
  else
    {
      /* Copy the entry.  */
      *desc = desc_table[cont++];

      /* If the next entry exists, return the index.  */
      if (cont < num)
	return cont;
    }
  
  return 0;
}

/* Track the int13 handler.  */
void
track_int13 (int drive)
{
  /* Nothing to do in the simulator.  */
}

/* Get the ROM configuration table.  */
unsigned long
get_rom_config_table (void)
{
  return 0;
}

/* Get APM BIOS information.  */
void
get_apm_info (void)
{
  /* Nothing to do in the simulator.  */
}

/* Get VBE controller information.  */
int
get_vbe_controller_info (struct vbe_controller *controller)
{
  /* Always fails.  */
  return 0;
}

/* Get VBE mode information.  */
int
get_vbe_mode_info (int mode_number, struct vbe_mode *mode)
{
  /* Always fails.  */
  return 0;
}

/* Set VBE mode.  */
int
set_vbe_mode (int mode_number)
{
  /* Always fails.  */
  return 0;
}

/* low-level timing info */
int
getrtsecs (void)
{
  /* FIXME: exact value is not important, so just return time_t for now. */
  return time (0);
}

int
currticks (void)
{
  struct timeval tv;
  long csecs;
  int ticks_per_csec, ticks_per_usec;

  /* Note: 18.2 ticks/sec.  */

  /* Get current time.  */
  gettimeofday (&tv, 0);

  /* Compute centiseconds.  */
  csecs = tv.tv_sec / 10;

  /* Ticks per centisecond.  */
  ticks_per_csec = csecs * 182;

  /* Ticks per microsecond.  */
  ticks_per_usec = (((tv.tv_sec - csecs * 10) * 1000000 + tv.tv_usec)
		    * 182 / 10000000);

  /* Sum them.  */
  return ticks_per_csec + ticks_per_usec;
}

/* displays an ASCII character.  IBM displays will translate some
   characters to special graphical ones */
void
console_putchar (int c)
{
  /* Curses doesn't have VGA fonts.  */
  switch (c)
    {
    case DISP_UL:
      c = ACS_ULCORNER;
      break;
    case DISP_UR:
      c = ACS_URCORNER;
      break;
    case DISP_LL:
      c = ACS_LLCORNER;
      break;
    case DISP_LR:
      c = ACS_LRCORNER;
      break;
    case DISP_HORIZ:
      c = ACS_HLINE;
      break;
    case DISP_VERT:
      c = ACS_VLINE;
      break;
    case DISP_LEFT:
      c = ACS_LARROW;
      break;
    case DISP_RIGHT:
      c = ACS_RARROW;
      break;
    case DISP_UP:
      c = ACS_UARROW;
      break;
    case DISP_DOWN:
      c = ACS_DARROW;
      break;
    default:
      break;
    }

#ifdef HAVE_LIBCURSES
  if (use_curses)
    {
      /* In ncurses, a newline is treated badly, so we emulate it in our
	 own way.  */
      if (c == '\n')
	{
	  int x, y;

	  getyx (stdscr, y, x);
	  if (y + 1 == LINES)
	    scroll (stdscr);
	  else
	    move (y + 1, x);
	}
      else if (isprint (c))
	{
	  int x, y;

	  getyx (stdscr, y, x);
	  if (x + 1 == COLS)
	    {
	      console_putchar ('\r');
	      console_putchar ('\n');
	    }
	  addch (c | console_current_color);
	}
      else
	{
	  addch (c);
	}
      
#ifdef REFRESH_IMMEDIATELY
      refresh ();
#endif
    }
  else
#endif
    {
      /* CR is not used in Unix.  */
      if (c != '\r')
	putchar (c);
    }
}

/* The store for ungetch simulation. This is necessary, because
   ncurses-1.9.9g is still used in the world and its ungetch is
   completely broken.  */
#ifdef HAVE_LIBCURSES
static int save_char = ERR;
#endif

static int
console_translate_key (int c)
{
  switch (c)
    {
    case KEY_LEFT:
      return 2;
    case KEY_RIGHT:
      return 6;
    case KEY_UP:
      return 16;
    case KEY_DOWN:
      return 14;
    case KEY_DC:
      return 4;
    case KEY_BACKSPACE:
      return 8;
    case KEY_HOME:
      return 1;
    case KEY_END:
      return 5;
    case KEY_PPAGE:
      return 7;
    case KEY_NPAGE:
      return 3;
    default:
      break;
    }