arch/x86/lib/zimage.c

   1 /*
   2  * Copyright (c) 2011 The Chromium OS Authors.
   3  * (C) Copyright 2002
   4  * Daniel Engström, Omicron Ceti AB, <daniel@omicron.se>
   5  *
   6  * See file CREDITS for list of people who contributed to this
   7  * project.
   8  *
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License as
  11  * published by the Free Software Foundation; either version 2 of
  12  * the License, or (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  22  * MA 02111-1307 USA
  23  */
  24
  25 /*
  26  * Linux x86 zImage and bzImage loading
  27  *
  28  * based on the procdure described in
  29  * linux/Documentation/i386/boot.txt
  30  */
  31
  32 #include <common.h>
  33 #include <asm/io.h>
  34 #include <asm/ptrace.h>
  35 #include <asm/zimage.h>
  36 #include <asm/realmode.h>
  37 #include <asm/byteorder.h>
  38 #include <asm/bootparam.h>
  39
  40 /*
  41  * Memory lay-out:
  42  *
  43  * relative to setup_base (which is 0x90000 currently)
  44  *
  45  *      0x0000-0x7FFF   Real mode kernel
  46  *      0x8000-0x8FFF   Stack and heap
  47  *      0x9000-0x90FF   Kernel command line
  48  */
  49 #define DEFAULT_SETUP_BASE      0x90000
  50 #define COMMAND_LINE_OFFSET     0x9000
  51 #define HEAP_END_OFFSET         0x8e00
  52
  53 #define COMMAND_LINE_SIZE       2048
  54
  55 static void build_command_line(char *command_line, int auto_boot)
  56 {
  57         char *env_command_line;
  58
  59         command_line[0] = '\0';
  60
  61         env_command_line =  getenv("bootargs");
  62
  63         /* set console= argument if we use a serial console */
  64         if (!strstr(env_command_line, "console=")) {
  65                 if (!strcmp(getenv("stdout"), "serial")) {
  66
  67                         /* We seem to use serial console */
  68                         sprintf(command_line, "console=ttyS0,%s ",
  69                                 getenv("baudrate"));
  70                 }
  71         }
  72
  73         if (auto_boot)
  74                 strcat(command_line, "auto ");
  75
  76         if (env_command_line)
  77                 strcat(command_line, env_command_line);
  78
  79         printf("Kernel command line: \"%s\"\n", command_line);
  80 }
  81
  82 void *load_zimage(char *image, unsigned long kernel_size,
  83                   unsigned long initrd_addr, unsigned long initrd_size,
  84                   int auto_boot)
  85 {
  86         struct boot_params *setup_base;
  87         int setup_size;
  88         int bootproto;
  89         int big_image;
  90         void *load_address;
  91
  92         struct boot_params *params = (struct boot_params *)image;
  93         struct setup_header *hdr = &params->hdr;
  94
  95         /* base address for real-mode segment */
  96         setup_base = (struct boot_params *)DEFAULT_SETUP_BASE;
  97
  98         if (KERNEL_MAGIC != hdr->boot_flag) {
  99                 printf("Error: Invalid Boot Flag "
 100                         "(found 0x%04x, expected 0x%04x)\n",
 101                         hdr->boot_flag, KERNEL_MAGIC);
 102                 return 0;
 103         } else {
 104                 printf("Valid Boot Flag\n");
 105         }
 106
 107         /* determine boot protocol version */
 108         if (KERNEL_V2_MAGIC == hdr->header) {
 109                 printf("Magic signature found\n");
 110
 111                 bootproto = hdr->version;
 112         } else {
 113                 /* Very old kernel */
 114                 printf("Magic signature not found\n");
 115                 bootproto = 0x0100;
 116         }
 117
 118         /* determine size of setup */
 119         if (0 == hdr->setup_sects) {
 120                 printf("Setup Sectors = 0 (defaulting to 4)\n");
 121                 setup_size = 5 * 512;
 122         } else {
 123                 setup_size = (hdr->setup_sects + 1) * 512;
 124         }
 125
 126         printf("Setup Size = 0x%8.8lx\n", (ulong)setup_size);
 127
 128         if (setup_size > SETUP_MAX_SIZE)
 129                 printf("Error: Setup is too large (%d bytes)\n", setup_size);
 130
 131         /* Determine image type */
 132         big_image = (bootproto >= 0x0200) &&
 133                     (hdr->loadflags & BIG_KERNEL_FLAG);
 134
 135         /* Determine load address */
 136         if (big_image)
 137                 load_address = (void *)BZIMAGE_LOAD_ADDR;
 138         else
 139                 load_address = (void *)ZIMAGE_LOAD_ADDR;
 140
 141         /* load setup */
 142         printf("Moving Real-Mode Code to 0x%8.8lx (%d bytes)\n",
 143                (ulong)setup_base, setup_size);
 144         memmove(setup_base, image, setup_size);
 145
 146         printf("Using boot protocol version %x.%02x\n",
 147                (bootproto & 0xff00) >> 8, bootproto & 0xff);
 148
 149         if (bootproto == 0x0100) {
 150                 setup_base->screen_info.cl_magic = COMMAND_LINE_MAGIC;
 151                 setup_base->screen_info.cl_offset = COMMAND_LINE_OFFSET;
 152
 153                 /*
 154                  * A very old kernel MUST have its real-mode code
 155                  * loaded at 0x90000
 156                  */
 157                 if ((u32)setup_base != 0x90000) {
 158                         /* Copy the real-mode kernel */
 159                         memmove((void *)0x90000, setup_base, setup_size);
 160
 161                         /* Copy the command line */
 162                         memmove((void *)0x99000,
 163                                 (u8 *)setup_base + COMMAND_LINE_OFFSET,
 164                                 COMMAND_LINE_SIZE);
 165
 166                          /* Relocated */
 167                         setup_base = (struct boot_params *)0x90000;
 168                 }
 169
 170                 /* It is recommended to clear memory up to the 32K mark */
 171                 memset((u8 *)0x90000 + setup_size, 0,
 172                        SETUP_MAX_SIZE - setup_size);
 173         }
 174
 175         /* We are now setting up the real-mode version of the header */
 176         hdr = &setup_base->hdr;
 177
 178         if (bootproto >= 0x0200) {
 179                 hdr->type_of_loader = 8;
 180
 181                 if (hdr->setup_sects >= 15) {
 182                         printf("Linux kernel version %s\n",
 183                                (char *)setup_base +
 184                                hdr->kernel_version + 0x200);
 185                 } else {
 186                         printf("Setup Sectors < 15 - "
 187                                "Cannot print kernel version.\n");
 188                 }
 189
 190                 if (initrd_addr) {
 191                         printf("Initial RAM disk at linear address "
 192                                "0x%08lx, size %ld bytes\n",
 193                                initrd_addr, initrd_size);
 194
 195                         hdr->ramdisk_image = initrd_addr;
 196                         hdr->ramdisk_size = initrd_size;
 197                 }
 198         }
 199
 200         if (bootproto >= 0x0201) {
 201                 hdr->heap_end_ptr = HEAP_END_OFFSET;
 202                 hdr->loadflags |= HEAP_FLAG;
 203         }
 204
 205         if (bootproto >= 0x0202) {
 206                 hdr->cmd_line_ptr =
 207                         (uintptr_t)setup_base + COMMAND_LINE_OFFSET;
 208         } else if (bootproto >= 0x0200) {
 209                 setup_base->screen_info.cl_magic = COMMAND_LINE_MAGIC;
 210                 setup_base->screen_info.cl_offset = COMMAND_LINE_OFFSET;
 211
 212                 hdr->setup_move_size = 0x9100;
 213         }
 214
 215         if (bootproto >= 0x0204)
 216                 kernel_size = hdr->syssize * 16;
 217         else
 218                 kernel_size -= setup_size;
 219
 220
 221         if (big_image) {
 222                 if ((kernel_size) > BZIMAGE_MAX_SIZE) {
 223                         printf("Error: bzImage kernel too big! "
 224                                 "(size: %ld, max: %d)\n",
 225                                 kernel_size, BZIMAGE_MAX_SIZE);
 226                         return 0;
 227                 }
 228         } else if ((kernel_size) > ZIMAGE_MAX_SIZE) {
 229                 printf("Error: zImage kernel too big! (size: %ld, max: %d)\n",
 230                        kernel_size, ZIMAGE_MAX_SIZE);
 231                 return 0;
 232         }
 233
 234         /* build command line at COMMAND_LINE_OFFSET */
 235         build_command_line((char *)setup_base + COMMAND_LINE_OFFSET, auto_boot);
 236
 237         printf("Loading %czImage at address 0x%08x (%ld bytes)\n",
 238                big_image ? 'b' : ' ', (u32)load_address, kernel_size);
 239
 240
 241         memmove(load_address, image + setup_size, kernel_size);
 242
 243         /* ready for booting */
 244         return setup_base;
 245 }
 246
 247 void boot_zimage(void *setup_base)
 248 {
 249         struct pt_regs regs;
 250
 251         memset(&regs, 0, sizeof(struct pt_regs));
 252         regs.xds = (u32)setup_base >> 4;
 253         regs.xes = regs.xds;
 254         regs.xss = regs.xds;
 255         regs.esp = 0x9000;
 256         regs.eflags = 0;
 257         enter_realmode(((u32)setup_base + SETUP_START_OFFSET) >> 4, 0,
 258                        &regs, &regs);
 259 }
 260
 261 int do_zboot(cmd_tbl_t *cmdtp, int flag, int argc, char *const argv[])
 262 {
 263         void *base_ptr;
 264         void *bzImage_addr = NULL;
 265         char *s;
 266         ulong bzImage_size = 0;
 267
 268         disable_interrupts();
 269
 270         /* Setup board for maximum PC/AT Compatibility */
 271         setup_pcat_compatibility();
 272
 273         if (argc >= 2) {
 274                 /* argv[1] holds the address of the bzImage */
 275                 s = argv[1];
 276         } else {
 277                 s = getenv("fileaddr");
 278         }
 279
 280         if (s)
 281                 bzImage_addr = (void *)simple_strtoul(s, NULL, 16);
 282
 283         if (argc >= 3)
 284                 /* argv[2] holds the size of the bzImage */
 285                 bzImage_size = simple_strtoul(argv[2], NULL, 16);
 286
 287         /* Lets look for */
 288         base_ptr = load_zimage(bzImage_addr, bzImage_size, 0, 0, 0);
 289
 290         if (!base_ptr) {
 291                 printf("## Kernel loading failed ...\n");
 292         } else {
 293                 printf("## Transferring control to Linux "
 294                        "(at address %08x) ...\n",
 295                        (u32)base_ptr);
 296
 297                 /* we assume that the kernel is in place */
 298                 printf("\nStarting kernel ...\n\n");
 299
 300                 boot_zimage(base_ptr);
 301                 /* does not return */
 302         }
 303
 304         return -1;
 305 }
 306
 307 U_BOOT_CMD(
 308         zboot, 2, 0,    do_zboot,
 309         "Boot bzImage",
 310         ""
 311 );