loader/i386/pc/linux.c

   1 /* linux.c - boot Linux zImage or bzImage */
   2 /*
   3  *  GRUB  --  GRand Unified Bootloader
   4  *  Copyright (C) 1999,2000,2001,2002,2003,2004,2005,2007,2008,2009,2010  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 #include <grub/i18n.h>
  34 #include <grub/mm.h>
  35 #include <grub/video.h>
  36
  37 #define GRUB_LINUX_CL_OFFSET            0x9000
  38 #define GRUB_LINUX_CL_END_OFFSET        0x90FF
  39
  40 static grub_dl_t my_mod;
  41
  42 static grub_size_t linux_mem_size;
  43 static int loaded;
  44
  45 static grub_err_t
  46 grub_linux_unload (void)
  47 {
  48   grub_dl_unref (my_mod);
  49   loaded = 0;
  50   return GRUB_ERR_NONE;
  51 }
  52
  53 static grub_err_t
  54 grub_linux16_boot (void)
  55 {
  56   grub_video_set_mode ("text", 0, 0);
  57   grub_linux16_real_boot ();
  58
  59   /* Not reached.  */
  60   return GRUB_ERR_NONE;
  61 }
  62
  63 static grub_err_t
  64 grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),
  65                 int argc, char *argv[])
  66 {
  67   grub_file_t file = 0;
  68   struct linux_kernel_header lh;
  69   grub_uint8_t setup_sects;
  70   grub_size_t real_size, prot_size;
  71   grub_ssize_t len;
  72   int i;
  73   char *dest;
  74
  75   grub_dl_ref (my_mod);
  76
  77   if (argc == 0)
  78     {
  79       grub_error (GRUB_ERR_BAD_ARGUMENT, "no kernel specified");
  80       goto fail;
  81     }
  82
  83   file = grub_file_open (argv[0]);
  84   if (! file)
  85     goto fail;
  86
  87   if ((grub_size_t) grub_file_size (file) > grub_os_area_size)
  88     {
  89       grub_error (GRUB_ERR_OUT_OF_RANGE, "too big kernel (0x%x > 0x%x)",
  90                   (grub_size_t) grub_file_size (file),
  91                   grub_os_area_size);
  92       goto fail;
  93     }
  94
  95   if (grub_file_read (file, &lh, sizeof (lh)) != sizeof (lh))
  96     {
  97       grub_error (GRUB_ERR_READ_ERROR, "cannot read the Linux header");
  98       goto fail;
  99     }
 100
 101   if (lh.boot_flag != grub_cpu_to_le16 (0xaa55))
 102     {
 103       grub_error (GRUB_ERR_BAD_OS, "invalid magic number");
 104       goto fail;
 105     }
 106
 107   if (lh.setup_sects > GRUB_LINUX_MAX_SETUP_SECTS)
 108     {
 109       grub_error (GRUB_ERR_BAD_OS, "too many setup sectors");
 110       goto fail;
 111     }
 112
 113   grub_linux_is_bzimage = 0;
 114   setup_sects = lh.setup_sects;
 115   linux_mem_size = 0;
 116
 117   if (lh.header == grub_cpu_to_le32 (GRUB_LINUX_MAGIC_SIGNATURE)
 118       && grub_le_to_cpu16 (lh.version) >= 0x0200)
 119     {
 120       grub_linux_is_bzimage = (lh.loadflags & GRUB_LINUX_FLAG_BIG_KERNEL);
 121       lh.type_of_loader = GRUB_LINUX_BOOT_LOADER_TYPE;
 122
 123       /* Put the real mode part at as a high location as possible.  */
 124       grub_linux_real_addr
 125         = (char *) UINT_TO_PTR (grub_mmap_get_lower ()
 126                                 - GRUB_LINUX_SETUP_MOVE_SIZE);
 127       /* But it must not exceed the traditional area.  */
 128       if (grub_linux_real_addr > (char *) GRUB_LINUX_OLD_REAL_MODE_ADDR)
 129         grub_linux_real_addr = (char *) GRUB_LINUX_OLD_REAL_MODE_ADDR;
 130
 131       if (grub_le_to_cpu16 (lh.version) >= 0x0201)
 132         {
 133           lh.heap_end_ptr = grub_cpu_to_le16 (GRUB_LINUX_HEAP_END_OFFSET);
 134           lh.loadflags |= GRUB_LINUX_FLAG_CAN_USE_HEAP;
 135         }
 136
 137       if (grub_le_to_cpu16 (lh.version) >= 0x0202)
 138         lh.cmd_line_ptr = grub_linux_real_addr + GRUB_LINUX_CL_OFFSET;
 139       else
 140         {
 141           lh.cl_magic = grub_cpu_to_le16 (GRUB_LINUX_CL_MAGIC);
 142           lh.cl_offset = grub_cpu_to_le16 (GRUB_LINUX_CL_OFFSET);
 143           lh.setup_move_size = grub_cpu_to_le16 (GRUB_LINUX_SETUP_MOVE_SIZE);
 144         }
 145     }
 146   else
 147     {
 148       /* Your kernel is quite old...  */
 149       lh.cl_magic = grub_cpu_to_le16 (GRUB_LINUX_CL_MAGIC);
 150       lh.cl_offset = grub_cpu_to_le16 (GRUB_LINUX_CL_OFFSET);
 151
 152       setup_sects = GRUB_LINUX_DEFAULT_SETUP_SECTS;
 153
 154       grub_linux_real_addr = (char *) GRUB_LINUX_OLD_REAL_MODE_ADDR;
 155     }
 156
 157   /* If SETUP_SECTS is not set, set it to the default (4).  */
 158   if (! setup_sects)
 159     setup_sects = GRUB_LINUX_DEFAULT_SETUP_SECTS;
 160
 161   real_size = setup_sects << GRUB_DISK_SECTOR_BITS;
 162   prot_size = grub_file_size (file) - real_size - GRUB_DISK_SECTOR_SIZE;
 163
 164   grub_linux_tmp_addr = (char *) GRUB_LINUX_BZIMAGE_ADDR + prot_size;
 165
 166   if (! grub_linux_is_bzimage
 167       && ((char *) GRUB_LINUX_ZIMAGE_ADDR + prot_size > grub_linux_real_addr))
 168     {
 169       grub_error (GRUB_ERR_BAD_OS, "too big zImage (0x%x > 0x%x), use bzImage instead",
 170                   (char *) GRUB_LINUX_ZIMAGE_ADDR + prot_size,
 171                   (grub_size_t) grub_linux_real_addr);
 172       goto fail;
 173     }
 174
 175   if (grub_linux_real_addr + GRUB_LINUX_SETUP_MOVE_SIZE
 176       > (char *) UINT_TO_PTR (grub_mmap_get_lower ()))
 177     {
 178       grub_error (GRUB_ERR_OUT_OF_RANGE,
 179                  "too small lower memory (0x%x > 0x%x)",
 180                   grub_linux_real_addr + GRUB_LINUX_SETUP_MOVE_SIZE,
 181                   (int) grub_mmap_get_lower ());
 182       goto fail;
 183     }
 184
 185   grub_printf ("   [Linux-%s, setup=0x%x, size=0x%x]\n",
 186                grub_linux_is_bzimage ? "bzImage" : "zImage", real_size, prot_size);
 187
 188   for (i = 1; i < argc; i++)
 189     if (grub_memcmp (argv[i], "vga=", 4) == 0)
 190       {
 191         /* Video mode selection support.  */
 192         grub_uint16_t vid_mode;
 193         char *val = argv[i] + 4;
 194
 195         if (grub_strcmp (val, "normal") == 0)
 196           vid_mode = GRUB_LINUX_VID_MODE_NORMAL;
 197         else if (grub_strcmp (val, "ext") == 0)
 198           vid_mode = GRUB_LINUX_VID_MODE_EXTENDED;
 199         else if (grub_strcmp (val, "ask") == 0)
 200           vid_mode = GRUB_LINUX_VID_MODE_ASK;
 201         else
 202           vid_mode = (grub_uint16_t) grub_strtoul (val, 0, 0);
 203
 204         if (grub_errno)
 205           goto fail;
 206
 207         lh.vid_mode = grub_cpu_to_le16 (vid_mode);
 208       }
 209     else if (grub_memcmp (argv[i], "mem=", 4) == 0)
 210       {
 211         char *val = argv[i] + 4;
 212
 213         linux_mem_size = grub_strtoul (val, &val, 0);
 214
 215         if (grub_errno)
 216           {
 217             grub_errno = GRUB_ERR_NONE;
 218             linux_mem_size = 0;
 219           }
 220         else
 221           {
 222             int shift = 0;
 223
 224             switch (grub_tolower (val[0]))
 225               {
 226               case 'g':
 227                 shift += 10;
 228               case 'm':
 229                 shift += 10;
 230               case 'k':
 231                 shift += 10;
 232               default:
 233                 break;
 234               }
 235
 236             /* Check an overflow.  */
 237             if (linux_mem_size > (~0UL >> shift))
 238               linux_mem_size = 0;
 239             else
 240               linux_mem_size <<= shift;
 241           }
 242       }
 243
 244   /* Put the real mode code at the temporary address.  */
 245   grub_memmove (grub_linux_tmp_addr, &lh, sizeof (lh));
 246
 247   len = real_size + GRUB_DISK_SECTOR_SIZE - sizeof (lh);
 248   if (grub_file_read (file, grub_linux_tmp_addr + sizeof (lh), len) != len)
 249     {
 250       grub_error (GRUB_ERR_FILE_READ_ERROR, "couldn't read file");
 251       goto fail;
 252     }
 253
 254   if (lh.header != grub_cpu_to_le32 (GRUB_LINUX_MAGIC_SIGNATURE)
 255       || grub_le_to_cpu16 (lh.version) < 0x0200)
 256     /* Clear the heap space.  */
 257     grub_memset (grub_linux_tmp_addr
 258                  + ((setup_sects + 1) << GRUB_DISK_SECTOR_BITS),
 259                  0,
 260                  ((GRUB_LINUX_MAX_SETUP_SECTS - setup_sects - 1)
 261                   << GRUB_DISK_SECTOR_BITS));
 262
 263   /* Specify the boot file.  */
 264   dest = grub_stpcpy (grub_linux_tmp_addr + GRUB_LINUX_CL_OFFSET,
 265                       "BOOT_IMAGE=");
 266   dest = grub_stpcpy (dest, argv[0]);
 267
 268   /* Copy kernel parameters.  */
 269   for (i = 1;
 270        i < argc
 271          && dest + grub_strlen (argv[i]) + 1 < (grub_linux_tmp_addr
 272                                                 + GRUB_LINUX_CL_END_OFFSET);
 273        i++)
 274     {
 275       *dest++ = ' ';
 276       dest = grub_stpcpy (dest, argv[i]);
 277     }
 278
 279   len = prot_size;
 280   if (grub_file_read (file, (void *) GRUB_LINUX_BZIMAGE_ADDR, len) != len)
 281     grub_error (GRUB_ERR_FILE_READ_ERROR, "couldn't read file");
 282
 283   if (grub_errno == GRUB_ERR_NONE)
 284     {
 285       grub_linux_prot_size = prot_size;
 286       grub_loader_set (grub_linux16_boot, grub_linux_unload, 1);
 287       loaded = 1;
 288     }
 289
 290  fail:
 291
 292   if (file)
 293     grub_file_close (file);
 294
 295   if (grub_errno != GRUB_ERR_NONE)
 296     {
 297       grub_dl_unref (my_mod);
 298       loaded = 0;
 299     }
 300
 301   return grub_errno;
 302 }
 303
 304 static grub_err_t
 305 grub_cmd_initrd (grub_command_t cmd __attribute__ ((unused)),
 306                  int argc, char *argv[])
 307 {
 308   grub_file_t file = 0;
 309   grub_ssize_t size;
 310   grub_addr_t addr_max, addr_min, addr;
 311   struct linux_kernel_header *lh;
 312
 313   if (argc == 0)
 314     {
 315       grub_error (GRUB_ERR_BAD_ARGUMENT, "no module specified");
 316       goto fail;
 317     }
 318
 319   if (!loaded)
 320     {
 321       grub_error (GRUB_ERR_BAD_ARGUMENT, "you need to load the kernel first");
 322       goto fail;
 323     }
 324
 325   lh = (struct linux_kernel_header *) grub_linux_tmp_addr;
 326
 327   if (!(lh->header == grub_cpu_to_le32 (GRUB_LINUX_MAGIC_SIGNATURE)
 328         && grub_le_to_cpu16 (lh->version) >= 0x0200))
 329     {
 330       grub_error (GRUB_ERR_BAD_OS, "the kernel is too old for initrd");
 331       goto fail;
 332     }
 333
 334   /* Get the highest address available for the initrd.  */
 335   if (grub_le_to_cpu16 (lh->version) >= 0x0203)
 336     {
 337       addr_max = grub_cpu_to_le32 (lh->initrd_addr_max);
 338
 339       /* XXX in reality, Linux specifies a bogus value, so
 340          it is necessary to make sure that ADDR_MAX does not exceed
 341          0x3fffffff.  */
 342       if (addr_max > GRUB_LINUX_INITRD_MAX_ADDRESS)
 343         addr_max = GRUB_LINUX_INITRD_MAX_ADDRESS;
 344     }
 345   else
 346     addr_max = GRUB_LINUX_INITRD_MAX_ADDRESS;
 347
 348   if (linux_mem_size != 0 && linux_mem_size < addr_max)
 349     addr_max = linux_mem_size;
 350
 351   /* Linux 2.3.xx has a bug in the memory range check, so avoid
 352      the last page.
 353      Linux 2.2.xx has a bug in the memory range check, which is
 354      worse than that of Linux 2.3.xx, so avoid the last 64kb.  */
 355   addr_max -= 0x10000;
 356
 357   if (addr_max > grub_os_area_addr + grub_os_area_size)
 358     addr_max = grub_os_area_addr + grub_os_area_size;
 359
 360   addr_min = (grub_addr_t) grub_linux_tmp_addr + GRUB_LINUX_CL_END_OFFSET;
 361
 362   file = grub_file_open (argv[0]);
 363   if (!file)
 364     goto fail;
 365
 366   size = grub_file_size (file);
 367
 368   /* Put the initrd as high as possible, 4KiB aligned.  */
 369   addr = (addr_max - size) & ~0xFFF;
 370
 371   if (addr < addr_min)
 372     {
 373       grub_error (GRUB_ERR_OUT_OF_RANGE, "the initrd is too big");
 374       goto fail;
 375     }
 376
 377   if (grub_file_read (file, (void *) addr, size) != size)
 378     {
 379       grub_error (GRUB_ERR_FILE_READ_ERROR, "couldn't read file");
 380       goto fail;
 381     }
 382
 383   lh->ramdisk_image = addr;
 384   lh->ramdisk_size = size;
 385
 386  fail:
 387   if (file)
 388     grub_file_close (file);
 389
 390   return grub_errno;
 391 }
 392
 393 static grub_command_t cmd_linux, cmd_initrd;
 394
 395 GRUB_MOD_INIT(linux16)
 396 {
 397   cmd_linux =
 398     grub_register_command ("linux16", grub_cmd_linux,
 399                            0, N_("Load Linux."));
 400   cmd_initrd =
 401     grub_register_command ("initrd16", grub_cmd_initrd,
 402                            0, N_("Load initrd."));
 403   my_mod = mod;
 404 }
 405
 406 GRUB_MOD_FINI(linux16)
 407 {
 408   grub_unregister_command (cmd_linux);
 409   grub_unregister_command (cmd_initrd);
 410 }