loader/i386/pc/linux.c

   1 /* linux.c - boot Linux zImage or bzImage */
   2 /*
   3  *  GRUB  --  GRand Unified Bootloader
   4  *  Copyright (C) 1999,2000,2001,2002,2003,2004,2005,2007,2008  Free Software Foundation, Inc.
   5  *
   6  *  GRUB is free software: you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation, either version 3 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  GRUB is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <grub/loader.h>
  21 #include <grub/machine/loader.h>
  22 #include <grub/file.h>
  23 #include <grub/err.h>
  24 #include <grub/device.h>
  25 #include <grub/disk.h>
  26 #include <grub/misc.h>
  27 #include <grub/types.h>
  28 #include <grub/machine/init.h>
  29 #include <grub/machine/memory.h>
  30 #include <grub/dl.h>
  31 #include <grub/cpu/linux.h>
  32 #include <grub/command.h>
  33
  34 #define GRUB_LINUX_CL_OFFSET            0x9000
  35 #define GRUB_LINUX_CL_END_OFFSET        0x90FF
  36
  37 static grub_dl_t my_mod;
  38
  39 static grub_size_t linux_mem_size;
  40 static int loaded;
  41
  42 static grub_err_t
  43 grub_linux_unload (void)
  44 {
  45   grub_dl_unref (my_mod);
  46   loaded = 0;
  47   return GRUB_ERR_NONE;
  48 }
  49
  50 static grub_err_t
  51 grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),
  52                 int argc, char *argv[])
  53 {
  54   grub_file_t file = 0;
  55   struct linux_kernel_header lh;
  56   grub_uint8_t setup_sects;
  57   grub_size_t real_size, prot_size;
  58   grub_ssize_t len;
  59   int i;
  60   char *dest;
  61
  62   grub_dl_ref (my_mod);
  63
  64   if (argc == 0)
  65     {
  66       grub_error (GRUB_ERR_BAD_ARGUMENT, "no kernel specified");
  67       goto fail;
  68     }
  69
  70   file = grub_file_open (argv[0]);
  71   if (! file)
  72     goto fail;
  73
  74   if ((grub_size_t) grub_file_size (file) > grub_os_area_size)
  75     {
  76       grub_error (GRUB_ERR_OUT_OF_RANGE, "too big kernel (0x%x > 0x%x)",
  77                   (grub_size_t) grub_file_size (file),
  78                   grub_os_area_size);
  79       goto fail;
  80     }
  81
  82   if (grub_file_read (file, (char *) &lh, sizeof (lh)) != sizeof (lh))
  83     {
  84       grub_error (GRUB_ERR_READ_ERROR, "cannot read the linux header");
  85       goto fail;
  86     }
  87
  88   if (lh.boot_flag != grub_cpu_to_le16 (0xaa55))
  89     {
  90       grub_error (GRUB_ERR_BAD_OS, "invalid magic number");
  91       goto fail;
  92     }
  93
  94   if (lh.setup_sects > GRUB_LINUX_MAX_SETUP_SECTS)
  95     {
  96       grub_error (GRUB_ERR_BAD_OS, "too many setup sectors");
  97       goto fail;
  98     }
  99
 100   grub_linux_is_bzimage = 0;
 101   setup_sects = lh.setup_sects;
 102   linux_mem_size = 0;
 103
 104   if (lh.header == grub_cpu_to_le32 (GRUB_LINUX_MAGIC_SIGNATURE)
 105       && grub_le_to_cpu16 (lh.version) >= 0x0200)
 106     {
 107       grub_linux_is_bzimage = (lh.loadflags & GRUB_LINUX_FLAG_BIG_KERNEL);
 108       lh.type_of_loader = GRUB_LINUX_BOOT_LOADER_TYPE;
 109
 110       /* Put the real mode part at as a high location as possible.  */
 111       grub_linux_real_addr
 112         = (char *) UINT_TO_PTR (grub_mmap_get_lower ()
 113                                 - GRUB_LINUX_SETUP_MOVE_SIZE);
 114       /* But it must not exceed the traditional area.  */
 115       if (grub_linux_real_addr > (char *) GRUB_LINUX_OLD_REAL_MODE_ADDR)
 116         grub_linux_real_addr = (char *) GRUB_LINUX_OLD_REAL_MODE_ADDR;
 117
 118       if (grub_le_to_cpu16 (lh.version) >= 0x0201)
 119         {
 120           lh.heap_end_ptr = grub_cpu_to_le16 (GRUB_LINUX_HEAP_END_OFFSET);
 121           lh.loadflags |= GRUB_LINUX_FLAG_CAN_USE_HEAP;
 122         }
 123
 124       if (grub_le_to_cpu16 (lh.version) >= 0x0202)
 125         lh.cmd_line_ptr = grub_linux_real_addr + GRUB_LINUX_CL_OFFSET;
 126       else
 127         {
 128           lh.cl_magic = grub_cpu_to_le16 (GRUB_LINUX_CL_MAGIC);
 129           lh.cl_offset = grub_cpu_to_le16 (GRUB_LINUX_CL_OFFSET);
 130           lh.setup_move_size = grub_cpu_to_le16 (GRUB_LINUX_SETUP_MOVE_SIZE);
 131         }
 132     }
 133   else
 134     {
 135       /* Your kernel is quite old...  */
 136       lh.cl_magic = grub_cpu_to_le16 (GRUB_LINUX_CL_MAGIC);
 137       lh.cl_offset = grub_cpu_to_le16 (GRUB_LINUX_CL_OFFSET);
 138
 139       setup_sects = GRUB_LINUX_DEFAULT_SETUP_SECTS;
 140
 141       grub_linux_real_addr = (char *) GRUB_LINUX_OLD_REAL_MODE_ADDR;
 142     }
 143
 144   /* If SETUP_SECTS is not set, set it to the default (4).  */
 145   if (! setup_sects)
 146     setup_sects = GRUB_LINUX_DEFAULT_SETUP_SECTS;
 147
 148   real_size = setup_sects << GRUB_DISK_SECTOR_BITS;
 149   prot_size = grub_file_size (file) - real_size - GRUB_DISK_SECTOR_SIZE;
 150
 151   grub_linux_tmp_addr = (char *) GRUB_LINUX_BZIMAGE_ADDR + prot_size;
 152
 153   if (! grub_linux_is_bzimage
 154       && ((char *) GRUB_LINUX_ZIMAGE_ADDR + prot_size > grub_linux_real_addr))
 155     {
 156       grub_error (GRUB_ERR_BAD_OS, "too big zImage (0x%x > 0x%x), use bzImage instead",
 157                   (char *) GRUB_LINUX_ZIMAGE_ADDR + prot_size,
 158                   (grub_size_t) grub_linux_real_addr);
 159       goto fail;
 160     }
 161
 162   if (grub_linux_real_addr + GRUB_LINUX_SETUP_MOVE_SIZE
 163       > (char *) UINT_TO_PTR (grub_mmap_get_lower ()))
 164     {
 165       grub_error (GRUB_ERR_OUT_OF_RANGE,
 166                  "too small lower memory (0x%x > 0x%x)",
 167                   grub_linux_real_addr + GRUB_LINUX_SETUP_MOVE_SIZE,
 168                   (int) grub_mmap_get_lower ());
 169       goto fail;
 170     }
 171
 172   grub_printf ("   [Linux-%s, setup=0x%x, size=0x%x]\n",
 173                grub_linux_is_bzimage ? "bzImage" : "zImage", real_size, prot_size);
 174
 175   for (i = 1; i < argc; i++)
 176     if (grub_memcmp (argv[i], "vga=", 4) == 0)
 177       {
 178         /* Video mode selection support.  */
 179         grub_uint16_t vid_mode;
 180         char *val = argv[i] + 4;
 181
 182         if (grub_strcmp (val, "normal") == 0)
 183           vid_mode = GRUB_LINUX_VID_MODE_NORMAL;
 184         else if (grub_strcmp (val, "ext") == 0)
 185           vid_mode = GRUB_LINUX_VID_MODE_EXTENDED;
 186         else if (grub_strcmp (val, "ask") == 0)
 187           vid_mode = GRUB_LINUX_VID_MODE_ASK;
 188         else
 189           vid_mode = (grub_uint16_t) grub_strtoul (val, 0, 0);
 190
 191         if (grub_errno)
 192           goto fail;
 193
 194         lh.vid_mode = grub_cpu_to_le16 (vid_mode);
 195       }
 196     else if (grub_memcmp (argv[i], "mem=", 4) == 0)
 197       {
 198         char *val = argv[i] + 4;
 199
 200         linux_mem_size = grub_strtoul (val, &val, 0);
 201
 202         if (grub_errno)
 203           {
 204             grub_errno = GRUB_ERR_NONE;
 205             linux_mem_size = 0;
 206           }
 207         else
 208           {
 209             int shift = 0;
 210
 211             switch (grub_tolower (val[0]))
 212               {
 213               case 'g':
 214                 shift += 10;
 215               case 'm':
 216                 shift += 10;
 217               case 'k':
 218                 shift += 10;
 219               default:
 220                 break;
 221               }
 222
 223             /* Check an overflow.  */
 224             if (linux_mem_size > (~0UL >> shift))
 225               linux_mem_size = 0;
 226             else
 227               linux_mem_size <<= shift;
 228           }
 229       }
 230
 231   /* Put the real mode code at the temporary address.  */
 232   grub_memmove (grub_linux_tmp_addr, &lh, sizeof (lh));
 233
 234   len = real_size + GRUB_DISK_SECTOR_SIZE - sizeof (lh);
 235   if (grub_file_read (file, grub_linux_tmp_addr + sizeof (lh), len) != len)
 236     {
 237       grub_error (GRUB_ERR_FILE_READ_ERROR, "Couldn't read file");
 238       goto fail;
 239     }
 240
 241   if (lh.header != grub_cpu_to_le32 (GRUB_LINUX_MAGIC_SIGNATURE)
 242       || grub_le_to_cpu16 (lh.version) < 0x0200)
 243     /* Clear the heap space.  */
 244     grub_memset (grub_linux_tmp_addr
 245                  + ((setup_sects + 1) << GRUB_DISK_SECTOR_BITS),
 246                  0,
 247                  ((GRUB_LINUX_MAX_SETUP_SECTS - setup_sects - 1)
 248                   << GRUB_DISK_SECTOR_BITS));
 249
 250   /* Specify the boot file.  */
 251   dest = grub_stpcpy (grub_linux_tmp_addr + GRUB_LINUX_CL_OFFSET,
 252                       "BOOT_IMAGE=");
 253   dest = grub_stpcpy (dest, argv[0]);
 254
 255   /* Copy kernel parameters.  */
 256   for (i = 1;
 257        i < argc
 258          && dest + grub_strlen (argv[i]) + 1 < (grub_linux_tmp_addr
 259                                                 + GRUB_LINUX_CL_END_OFFSET);
 260        i++)
 261     {
 262       *dest++ = ' ';
 263       dest = grub_stpcpy (dest, argv[i]);
 264     }
 265
 266   len = prot_size;
 267   if (grub_file_read (file, (char *) GRUB_LINUX_BZIMAGE_ADDR, len) != len)
 268     grub_error (GRUB_ERR_FILE_READ_ERROR, "Couldn't read file");
 269
 270   if (grub_errno == GRUB_ERR_NONE)
 271     {
 272       grub_linux_prot_size = prot_size;
 273       grub_loader_set (grub_linux16_boot, grub_linux_unload, 1);
 274       loaded = 1;
 275     }
 276
 277  fail:
 278
 279   if (file)
 280     grub_file_close (file);
 281
 282   if (grub_errno != GRUB_ERR_NONE)
 283     {
 284       grub_dl_unref (my_mod);
 285       loaded = 0;
 286     }
 287
 288   return grub_errno;
 289 }
 290
 291 static grub_err_t
 292 grub_cmd_initrd (grub_command_t cmd __attribute__ ((unused)),
 293                  int argc, char *argv[])
 294 {
 295   grub_file_t file = 0;
 296   grub_ssize_t size;
 297   grub_addr_t addr_max, addr_min, addr;
 298   struct linux_kernel_header *lh;
 299
 300   if (argc == 0)
 301     {
 302       grub_error (GRUB_ERR_BAD_ARGUMENT, "No module specified");
 303       goto fail;
 304     }
 305
 306   if (!loaded)
 307     {
 308       grub_error (GRUB_ERR_BAD_ARGUMENT, "You need to load the kernel first.");
 309       goto fail;
 310     }
 311
 312   lh = (struct linux_kernel_header *) grub_linux_tmp_addr;
 313
 314   if (!(lh->header == grub_cpu_to_le32 (GRUB_LINUX_MAGIC_SIGNATURE)
 315         && grub_le_to_cpu16 (lh->version) >= 0x0200))
 316     {
 317       grub_error (GRUB_ERR_BAD_OS, "The kernel is too old for initrd.");
 318       goto fail;
 319     }
 320
 321   /* Get the highest address available for the initrd.  */
 322   if (grub_le_to_cpu16 (lh->version) >= 0x0203)
 323     {
 324       addr_max = grub_cpu_to_le32 (lh->initrd_addr_max);
 325
 326       /* XXX in reality, Linux specifies a bogus value, so
 327          it is necessary to make sure that ADDR_MAX does not exceed
 328          0x3fffffff.  */
 329       if (addr_max > GRUB_LINUX_INITRD_MAX_ADDRESS)
 330         addr_max = GRUB_LINUX_INITRD_MAX_ADDRESS;
 331     }
 332   else
 333     addr_max = GRUB_LINUX_INITRD_MAX_ADDRESS;
 334
 335   if (linux_mem_size != 0 && linux_mem_size < addr_max)
 336     addr_max = linux_mem_size;
 337
 338   /* Linux 2.3.xx has a bug in the memory range check, so avoid
 339      the last page.
 340      Linux 2.2.xx has a bug in the memory range check, which is
 341      worse than that of Linux 2.3.xx, so avoid the last 64kb.  */
 342   addr_max -= 0x10000;
 343
 344   if (addr_max > grub_os_area_addr + grub_os_area_size)
 345     addr_max = grub_os_area_addr + grub_os_area_size;
 346
 347   addr_min = (grub_addr_t) grub_linux_tmp_addr + GRUB_LINUX_CL_END_OFFSET;
 348
 349   file = grub_file_open (argv[0]);
 350   if (!file)
 351     goto fail;
 352
 353   size = grub_file_size (file);
 354
 355   /* Put the initrd as high as possible, 4KiB aligned.  */
 356   addr = (addr_max - size) & ~0xFFF;
 357
 358   if (addr < addr_min)
 359     {
 360       grub_error (GRUB_ERR_OUT_OF_RANGE, "The initrd is too big");
 361       goto fail;
 362     }
 363
 364   if (grub_file_read (file, (void *)addr, size) != size)
 365     {
 366       grub_error (GRUB_ERR_FILE_READ_ERROR, "Couldn't read file");
 367       goto fail;
 368     }
 369
 370   lh->ramdisk_image = addr;
 371   lh->ramdisk_size = size;
 372
 373  fail:
 374   if (file)
 375     grub_file_close (file);
 376
 377   return grub_errno;
 378 }
 379
 380 static grub_command_t cmd_linux, cmd_initrd;
 381
 382 GRUB_MOD_INIT(linux16)
 383 {
 384   cmd_linux =
 385     grub_register_command ("linux16", grub_cmd_linux,
 386                            0, "load linux");
 387   cmd_initrd =
 388     grub_register_command ("initrd16", grub_cmd_initrd,
 389                            0, "load initrd");
 390   my_mod = mod;
 391 }
 392
 393 GRUB_MOD_FINI(linux16)
 394 {
 395   grub_unregister_command (cmd_linux);
 396   grub_unregister_command (cmd_initrd);
 397 }