arch/x86/lib/zimage.c

   1 /*
   2  * (C) Copyright 2002
   3  * Daniel Engström, Omicron Ceti AB, <daniel@omicron.se>
   4  *
   5  * See file CREDITS for list of people who contributed to this
   6  * project.
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License as
  10  * published by the Free Software Foundation; either version 2 of
  11  * the License, or (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  21  * MA 02111-1307 USA
  22  */
  23
  24 /*
  25  * Linux x86 zImage and bzImage loading
  26  *
  27  * based on the procdure described in
  28  * linux/Documentation/i386/boot.txt
  29  */
  30
  31 #include <common.h>
  32 #include <asm/io.h>
  33 #include <asm/ptrace.h>
  34 #include <asm/zimage.h>
  35 #include <asm/realmode.h>
  36 #include <asm/byteorder.h>
  37 #include <asm/bootparam.h>
  38
  39 /*
  40  * Memory lay-out:
  41  *
  42  * relative to setup_base (which is 0x90000 currently)
  43  *
  44  *      0x0000-0x7FFF   Real mode kernel
  45  *      0x8000-0x8FFF   Stack and heap
  46  *      0x9000-0x90FF   Kernel command line
  47  */
  48 #define DEFAULT_SETUP_BASE      0x90000
  49 #define COMMAND_LINE_OFFSET     0x9000
  50 #define HEAP_END_OFFSET         0x8e00
  51
  52 #define COMMAND_LINE_SIZE       2048
  53
  54 static void build_command_line(char *command_line, int auto_boot)
  55 {
  56         char *env_command_line;
  57
  58         command_line[0] = '\0';
  59
  60         env_command_line =  getenv("bootargs");
  61
  62         /* set console= argument if we use a serial console */
  63         if (!strstr(env_command_line, "console=")) {
  64                 if (!strcmp(getenv("stdout"), "serial")) {
  65
  66                         /* We seem to use serial console */
  67                         sprintf(command_line, "console=ttyS0,%s ",
  68                                 getenv("baudrate"));
  69                 }
  70         }
  71
  72         if (auto_boot)
  73                 strcat(command_line, "auto ");
  74
  75         if (env_command_line)
  76                 strcat(command_line, env_command_line);
  77
  78         printf("Kernel command line: \"%s\"\n", command_line);
  79 }
  80
  81 void *load_zimage(char *image, unsigned long kernel_size,
  82                   unsigned long initrd_addr, unsigned long initrd_size,
  83                   int auto_boot)
  84 {
  85         void *setup_base;
  86         int setup_size;
  87         int bootproto;
  88         int big_image;
  89         void *load_address;
  90         struct setup_header *hdr;
  91
  92         hdr = (struct setup_header *)(image + SETUP_SECTS_OFF);
  93
  94         /* base address for real-mode segment */
  95         setup_base = (void *)DEFAULT_SETUP_BASE;
  96
  97         if (KERNEL_MAGIC != hdr->boot_flag) {
  98                 printf("Error: Invalid Boot Flag (found 0x%04x, expected 0x%04x)\n",
  99                        hdr->boot_flag, KERNEL_MAGIC);
 100                 return 0;
 101         } else {
 102                 printf("Valid Boot Flag\n");
 103         }
 104
 105         /* determine boot protocol version */
 106         if (KERNEL_V2_MAGIC == hdr->header) {
 107                 printf("Magic signature found\n");
 108
 109                 bootproto = hdr->version;
 110         } else {
 111                 /* Very old kernel */
 112                 printf("Magic signature not found\n");
 113                 bootproto = 0x0100;
 114         }
 115
 116         /* determine size of setup */
 117         if (0 == hdr->setup_sects) {
 118                 printf("Setup Sectors = 0 (defaulting to 4)\n");
 119                 setup_size = 5 * 512;
 120         } else {
 121                 setup_size = (hdr->setup_sects + 1) * 512;
 122         }
 123
 124         printf("Setup Size = 0x%8.8lx\n", (ulong)setup_size);
 125
 126         if (setup_size > SETUP_MAX_SIZE)
 127                 printf("Error: Setup is too large (%d bytes)\n", setup_size);
 128
 129         /* Determine image type */
 130         big_image = (bootproto >= 0x0200) &&
 131                     (hdr->loadflags & BIG_KERNEL_FLAG);
 132
 133         /* Determine load address */
 134         load_address = (void *)(big_image ?
 135                                 BZIMAGE_LOAD_ADDR :
 136                                 ZIMAGE_LOAD_ADDR);
 137
 138         /* load setup */
 139         printf("Moving Real-Mode Code to 0x%8.8lx (%d bytes)\n",
 140                (ulong)setup_base, setup_size);
 141         memmove(setup_base, image, setup_size);
 142
 143         printf("Using boot protocol version %x.%02x\n",
 144                (bootproto & 0xff00) >> 8, bootproto & 0xff);
 145
 146         if (bootproto == 0x0100) {
 147                 *(u16 *)(setup_base + CMD_LINE_MAGIC_OFF) = COMMAND_LINE_MAGIC;
 148                 *(u16 *)(setup_base + CMD_LINE_OFFSET_OFF) = COMMAND_LINE_OFFSET;
 149
 150                 /*
 151                  * A very old kernel MUST have its real-mode code
 152                  * loaded at 0x90000
 153                  */
 154                 if ((u32)setup_base != 0x90000) {
 155                         /* Copy the real-mode kernel */
 156                         memmove((void *)0x90000, setup_base, setup_size);
 157
 158                         /* Copy the command line */
 159                         memmove((void *)0x99000,
 160                                 setup_base + COMMAND_LINE_OFFSET,
 161                                 COMMAND_LINE_SIZE);
 162
 163                          /* Relocated */
 164                         setup_base = (void *)0x90000;
 165                 }
 166
 167                 /* It is recommended to clear memory up to the 32K mark */
 168                 memset((void *)0x90000 + setup_size, 0,
 169                        SETUP_MAX_SIZE-setup_size);
 170         }
 171
 172         /* We are now setting up the real-mode version of the header */
 173         hdr = (struct setup_header *)(setup_base + SETUP_SECTS_OFF);
 174
 175         if (bootproto >= 0x0200) {
 176                 hdr->type_of_loader = 8;
 177
 178                 if (hdr->setup_sects >= 15)
 179                         printf("Linux kernel version %s\n",
 180                                (char *)(setup_base +
 181                                         (hdr->kernel_version + 0x200)));
 182                 else
 183                         printf("Setup Sectors < 15 - Cannot print kernel version.\n");
 184
 185                 if (initrd_addr) {
 186                         printf("Initial RAM disk at linear address 0x%08lx, size %ld bytes\n",
 187                                initrd_addr, initrd_size);
 188
 189                         hdr->ramdisk_image = initrd_addr;
 190                         hdr->ramdisk_size = initrd_size;
 191                 }
 192         }
 193
 194         if (bootproto >= 0x0201) {
 195                 hdr->heap_end_ptr = HEAP_END_OFFSET;
 196                 hdr->loadflags |= HEAP_FLAG;
 197         }
 198
 199         if (bootproto >= 0x0202) {
 200                 hdr->cmd_line_ptr = (u32)setup_base + COMMAND_LINE_OFFSET;
 201         } else if (bootproto >= 0x0200) {
 202
 203                 *(u16 *)(setup_base + CMD_LINE_MAGIC_OFF) = COMMAND_LINE_MAGIC;
 204                 *(u16 *)(setup_base + CMD_LINE_OFFSET_OFF) = COMMAND_LINE_OFFSET;
 205
 206                 hdr->setup_move_size = 0x9100;
 207         }
 208
 209         if (bootproto >= 0x0204)
 210                 kernel_size = hdr->syssize * 16;
 211         else
 212                 kernel_size -= setup_size;
 213
 214
 215         if (big_image) {
 216                 if ((kernel_size) > BZIMAGE_MAX_SIZE) {
 217                         printf("Error: bzImage kernel too big! (size: %ld, max: %d)\n",
 218                                kernel_size, BZIMAGE_MAX_SIZE);
 219                         return 0;
 220                 }
 221
 222         } else if ((kernel_size) > ZIMAGE_MAX_SIZE) {
 223                 printf("Error: zImage kernel too big! (size: %ld, max: %d)\n",
 224                        kernel_size, ZIMAGE_MAX_SIZE);
 225                 return 0;
 226         }
 227
 228         /* build command line at COMMAND_LINE_OFFSET */
 229         build_command_line(setup_base + COMMAND_LINE_OFFSET, auto_boot);
 230
 231         printf("Loading %czImage at address 0x%08x (%ld bytes)\n",
 232                big_image ? 'b' : ' ', (u32)load_address, kernel_size);
 233
 234
 235         memmove(load_address, image + setup_size, kernel_size);
 236
 237         /* ready for booting */
 238         return setup_base;
 239 }
 240
 241 void boot_zimage(void *setup_base)
 242 {
 243         struct pt_regs regs;
 244
 245         memset(&regs, 0, sizeof(struct pt_regs));
 246         regs.xds = (u32)setup_base >> 4;
 247         regs.xes = regs.xds;
 248         regs.xss = regs.xds;
 249         regs.esp = 0x9000;
 250         regs.eflags = 0;
 251         enter_realmode(((u32)setup_base+SETUP_START_OFFSET)>>4, 0, &regs,
 252                        &regs);
 253 }
 254
 255 int do_zboot(cmd_tbl_t *cmdtp, int flag, int argc, char *const argv[])
 256 {
 257         void *base_ptr;
 258         void *bzImage_addr = NULL;
 259         char *s;
 260         ulong bzImage_size = 0;
 261
 262         disable_interrupts();
 263
 264         /* Setup board for maximum PC/AT Compatibility */
 265         setup_pcat_compatibility();
 266
 267         if (argc >= 2)
 268                 /* argv[1] holds the address of the bzImage */
 269                 s = argv[1];
 270         else
 271                 s = getenv("fileaddr");
 272
 273         if (s)
 274                 bzImage_addr = (void *)simple_strtoul(s, NULL, 16);
 275
 276         if (argc >= 3)
 277                 /* argv[2] holds the size of the bzImage */
 278                 bzImage_size = simple_strtoul(argv[2], NULL, 16);
 279
 280         /* Lets look for*/
 281         base_ptr = load_zimage(bzImage_addr, bzImage_size, 0, 0, 0);
 282
 283         if (!base_ptr) {
 284                 printf("## Kernel loading failed ...\n");
 285         } else {
 286                 printf("## Transferring control to Linux (at address %08x) ...\n",
 287                         (u32)base_ptr);
 288
 289                 /* we assume that the kernel is in place */
 290                 printf("\nStarting kernel ...\n\n");
 291
 292                 boot_zimage(base_ptr);
 293                 /* does not return */
 294         }
 295
 296         return -1;
 297 }
 298
 299 U_BOOT_CMD(
 300         zboot, 2, 0,    do_zboot,
 301         "Boot bzImage",
 302         ""
 303 );