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 (NULL == strstr(env_command_line, "console=")) {
  64                 if (0==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
  76         if (NULL != env_command_line) {
  77                 strcat(command_line, env_command_line);
  78         }
  79
  80
  81         printf("Kernel command line: \"%s\"\n", command_line);
  82 }
  83
  84 void *load_zimage(char *image, unsigned long kernel_size,
  85                   unsigned long initrd_addr, unsigned long initrd_size,
  86                   int auto_boot)
  87 {
  88         void *setup_base;
  89         int setup_size;
  90         int bootproto;
  91         int big_image;
  92         void *load_address;
  93
  94         struct setup_header *hdr = (struct setup_header *)(image + SETUP_SECTS_OFF);
  95
  96         setup_base = (void*)DEFAULT_SETUP_BASE; /* base address for real-mode segment */
  97
  98         if (KERNEL_MAGIC != hdr->boot_flag) {
  99                 printf("Error: Invalid Boot Flag (found 0x%04x, expected 0x%04x)\n",
 100                                 hdr->boot_flag, KERNEL_MAGIC);
 101                 return 0;
 102         } else {
 103                 printf("Valid Boot Flag\n");
 104         }
 105
 106         /* determine boot protocol version */
 107         if (KERNEL_V2_MAGIC == hdr->header) {
 108                 printf("Magic signature found\n");
 109
 110                 bootproto = hdr->version;
 111         } else {
 112                 /* Very old kernel */
 113                 printf("Magic signature not found\n");
 114                 bootproto = 0x0100;
 115         }
 116
 117         /* determine size of setup */
 118         if (0 == hdr->setup_sects) {
 119                 printf("Setup Sectors = 0 (defaulting to 4)\n");
 120                 setup_size = 5 * 512;
 121         } else {
 122                 setup_size = (hdr->setup_sects + 1) * 512;
 123         }
 124
 125         printf("Setup Size = 0x%8.8lx\n", (ulong)setup_size);
 126
 127         if (setup_size > SETUP_MAX_SIZE) {
 128                 printf("Error: Setup is too large (%d bytes)\n", setup_size);
 129         }
 130
 131         /* Determine image type */
 132         big_image = (bootproto >= 0x0200) && (hdr->loadflags & BIG_KERNEL_FLAG);
 133
 134         /* Determine load address */
 135         load_address = (void*)(big_image ? BZIMAGE_LOAD_ADDR : ZIMAGE_LOAD_ADDR);
 136
 137         /* load setup */
 138         printf("Moving Real-Mode Code to 0x%8.8lx (%d bytes)\n", (ulong)setup_base, setup_size);
 139         memmove(setup_base, image, setup_size);
 140
 141         printf("Using boot protocol version %x.%02x\n",
 142                (bootproto & 0xff00) >> 8, bootproto & 0xff);
 143
 144         if (bootproto == 0x0100) {
 145
 146                 *(u16*)(setup_base + CMD_LINE_MAGIC_OFF) = COMMAND_LINE_MAGIC;
 147                 *(u16*)(setup_base + CMD_LINE_OFFSET_OFF) = COMMAND_LINE_OFFSET;
 148
 149                 /* A very old kernel MUST have its real-mode code
 150                  * loaded at 0x90000 */
 151
 152                 if ((u32)setup_base != 0x90000) {
 153                         /* Copy the real-mode kernel */
 154                         memmove((void*)0x90000, setup_base, setup_size);
 155                         /* Copy the command line */
 156                         memmove((void*)0x99000, setup_base+COMMAND_LINE_OFFSET,
 157                                COMMAND_LINE_SIZE);
 158
 159                         setup_base = (void*)0x90000;             /* Relocated */
 160                 }
 161
 162                 /* It is recommended to clear memory up to the 32K mark */
 163                 memset((void*)0x90000 + setup_size, 0, SETUP_MAX_SIZE-setup_size);
 164         }
 165
 166         /* We are now setting up the real-mode version of the header */
 167         hdr = (struct setup_header *)(setup_base + SETUP_SECTS_OFF);
 168
 169         if (bootproto >= 0x0200) {
 170                 hdr->type_of_loader = 8;
 171
 172                 if (hdr->setup_sects >= 15)
 173                         printf("Linux kernel version %s\n", (char *)
 174                                         (setup_base + (hdr->kernel_version + 0x200)));
 175                 else
 176                         printf("Setup Sectors < 15 - Cannot print kernel version.\n");
 177
 178                 if (initrd_addr) {
 179                         printf("Initial RAM disk at linear address 0x%08lx, size %ld bytes\n",
 180                                initrd_addr, initrd_size);
 181
 182                         hdr->ramdisk_image = initrd_addr;
 183                         hdr->ramdisk_size = initrd_size;
 184                 }
 185         }
 186
 187         if (bootproto >= 0x0201) {
 188                 hdr->heap_end_ptr = HEAP_END_OFFSET;
 189                 hdr->loadflags |= HEAP_FLAG;
 190         }
 191
 192         if (bootproto >= 0x0202) {
 193                 hdr->cmd_line_ptr = (u32)setup_base + COMMAND_LINE_OFFSET;
 194         } else if (bootproto >= 0x0200) {
 195
 196                 *(u16*)(setup_base + CMD_LINE_MAGIC_OFF) = COMMAND_LINE_MAGIC;
 197                 *(u16*)(setup_base + CMD_LINE_OFFSET_OFF) = COMMAND_LINE_OFFSET;
 198
 199                 hdr->setup_move_size = 0x9100;
 200         }
 201
 202         if (bootproto >= 0x0204)
 203                 kernel_size = hdr->syssize * 16;
 204         else
 205                 kernel_size -= setup_size;
 206
 207
 208         if (big_image) {
 209                 if ((kernel_size) > BZIMAGE_MAX_SIZE) {
 210                         printf("Error: bzImage kernel too big! (size: %ld, max: %d)\n",
 211                                kernel_size, BZIMAGE_MAX_SIZE);
 212                         return 0;
 213                 }
 214
 215         } else if ((kernel_size) > ZIMAGE_MAX_SIZE) {
 216                 printf("Error: zImage kernel too big! (size: %ld, max: %d)\n",
 217                        kernel_size, ZIMAGE_MAX_SIZE);
 218                 return 0;
 219         }
 220
 221         /* build command line at COMMAND_LINE_OFFSET */
 222         build_command_line(setup_base + COMMAND_LINE_OFFSET, auto_boot);
 223
 224         printf("Loading %czImage at address 0x%08x (%ld bytes)\n", big_image ? 'b' : ' ',
 225                (u32)load_address, kernel_size);
 226
 227
 228         memmove(load_address, image + setup_size, kernel_size);
 229
 230         /* ready for booting */
 231         return setup_base;
 232 }
 233
 234 void boot_zimage(void *setup_base)
 235 {
 236         struct pt_regs regs;
 237
 238         memset(&regs, 0, sizeof(struct pt_regs));
 239         regs.xds = (u32)setup_base >> 4;
 240         regs.xes = regs.xds;
 241         regs.xss = regs.xds;
 242         regs.esp = 0x9000;
 243         regs.eflags = 0;
 244         enter_realmode(((u32)setup_base+SETUP_START_OFFSET)>>4, 0, &regs, &regs);
 245 }
 246
 247 int do_zboot (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 248 {
 249         void *base_ptr;
 250         void *bzImage_addr = NULL;
 251         char *s;
 252         ulong bzImage_size = 0;
 253
 254         disable_interrupts();
 255
 256         /* Setup board for maximum PC/AT Compatibility */
 257         setup_pcat_compatibility();
 258
 259         if (argc >= 2)
 260                 /* argv[1] holds the address of the bzImage */
 261                 s = argv[1];
 262         else
 263                 s = getenv("fileaddr");
 264
 265         if (s)
 266                 bzImage_addr = (void *)simple_strtoul(s, NULL, 16);
 267
 268         if (argc >= 3)
 269                 /* argv[2] holds the size of the bzImage */
 270                 bzImage_size = simple_strtoul(argv[2], NULL, 16);
 271
 272         /* Lets look for*/
 273         base_ptr = load_zimage (bzImage_addr, bzImage_size, 0, 0, 0);
 274
 275         if (NULL == base_ptr) {
 276                 printf ("## Kernel loading failed ...\n");
 277         } else {
 278                 printf ("## Transferring control to Linux (at address %08x) ...\n",
 279                         (u32)base_ptr);
 280
 281                 /* we assume that the kernel is in place */
 282                 printf("\nStarting kernel ...\n\n");
 283
 284                 boot_zimage(base_ptr);
 285                 /* does not return */
 286         }
 287
 288         return -1;
 289 }
 290
 291 U_BOOT_CMD(
 292         zboot, 2, 0,    do_zboot,
 293         "Boot bzImage",
 294         ""
 295 );