lib_i386/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 i386 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
  38 /*
  39  * Memory lay-out:
  40  *
  41  * relative to setup_base (which is 0x90000 currently)
  42  *
  43  *      0x0000-0x7FFF   Real mode kernel
  44  *      0x8000-0x8FFF   Stack and heap
  45  *      0x9000-0x90FF   Kernel command line
  46  */
  47 #define DEFAULT_SETUP_BASE  0x90000
  48 #define COMMAND_LINE_OFFSET 0x9000
  49 #define HEAP_END_OFFSET     0x8e00
  50
  51 #define COMMAND_LINE_SIZE   2048
  52
  53 static void build_command_line(char *command_line, int auto_boot)
  54 {
  55         char *env_command_line;
  56
  57         command_line[0] = '\0';
  58
  59         env_command_line =  getenv("bootargs");
  60
  61         /* set console= argument if we use a serial console */
  62         if (NULL == strstr(env_command_line, "console=")) {
  63                 if (0==strcmp(getenv("stdout"), "serial")) {
  64
  65                         /* We seem to use serial console */
  66                         sprintf(command_line, "console=ttyS0,%s ",
  67                                  getenv("baudrate"));
  68                 }
  69         }
  70
  71         if (auto_boot) {
  72                 strcat(command_line, "auto ");
  73         }
  74
  75         if (NULL != env_command_line) {
  76                 strcat(command_line, env_command_line);
  77         }
  78
  79
  80         printf("Kernel command line: \"%s\"\n", command_line);
  81 }
  82
  83 void *load_zimage(char *image, unsigned long kernel_size,
  84                   unsigned long initrd_addr, unsigned long initrd_size,
  85                   int auto_boot)
  86 {
  87         void *setup_base;
  88         int setup_size;
  89         int bootproto;
  90         int big_image;
  91         void *load_address;
  92
  93
  94         setup_base = (void*)DEFAULT_SETUP_BASE; /* base address for real-mode segment */
  95
  96         if (KERNEL_MAGIC != *(u16*)(image + BOOT_FLAG_OFF)) {
  97                 printf("Error: Invalid kernel magic (found 0x%04x, expected 0xaa55)\n",
  98                        *(u16*)(image + BOOT_FLAG_OFF));
  99                 return 0;
 100         }
 101
 102
 103         /* determine boot protocol version */
 104         if (KERNEL_V2_MAGIC == *(u32*)(image+HEADER_OFF)) {
 105                 bootproto = *(u16*)(image+VERSION_OFF);
 106         } else {
 107                 /* Very old kernel */
 108                 bootproto = 0x0100;
 109         }
 110
 111         /* determine size of setup */
 112         if (0 == *(u8*)(image + SETUP_SECTS_OFF)) {
 113                 setup_size = 5 * 512;
 114         } else {
 115                 setup_size = (*(u8*)(image + SETUP_SECTS_OFF) + 1) * 512;
 116         }
 117
 118         if (setup_size > SETUP_MAX_SIZE) {
 119                 printf("Error: Setup is too large (%d bytes)\n", setup_size);
 120         }
 121
 122         /* Determine image type */
 123         big_image = (bootproto >= 0x0200) && (*(u8*)(image + LOADFLAGS_OFF) & BIG_KERNEL_FLAG);
 124
 125         /* Derermine load address */
 126         load_address = (void*)(big_image ? BZIMAGE_LOAD_ADDR:ZIMAGE_LOAD_ADDR);
 127
 128         /* load setup */
 129         memmove(setup_base, image, setup_size);
 130
 131         printf("Using boot protocol version %x.%02x\n",
 132                (bootproto & 0xff00) >> 8, bootproto & 0xff);
 133
 134
 135         if (bootproto == 0x0100) {
 136
 137                 *(u16*)(setup_base + CMD_LINE_MAGIC_OFF) = COMMAND_LINE_MAGIC;
 138                 *(u16*)(setup_base + CMD_LINE_OFFSET_OFF) = COMMAND_LINE_OFFSET;
 139
 140                 /* A very old kernel MUST have its real-mode code
 141                  * loaded at 0x90000 */
 142
 143                 if ((u32)setup_base != 0x90000) {
 144                         /* Copy the real-mode kernel */
 145                         memmove((void*)0x90000, setup_base, setup_size);
 146                         /* Copy the command line */
 147                         memmove((void*)0x99000, setup_base+COMMAND_LINE_OFFSET,
 148                                COMMAND_LINE_SIZE);
 149
 150                         setup_base = (void*)0x90000;             /* Relocated */
 151                 }
 152
 153                 /* It is recommended to clear memory up to the 32K mark */
 154                 memset((void*)0x90000 + setup_size, 0, SETUP_MAX_SIZE-setup_size);
 155         }
 156
 157         if (bootproto >= 0x0200) {
 158                 *(u8*)(setup_base + TYPE_OF_LOADER_OFF) = 0xff;
 159                 printf("Linux kernel version %s\n",
 160                        (char*)(setup_base + SETUP_START_OFFSET +
 161                                *(u16*)(setup_base + START_SYS_OFF + 2)));
 162
 163                 if (initrd_addr) {
 164                         printf("Initial RAM disk at linear address 0x%08lx, size %ld bytes\n",
 165                                initrd_addr, initrd_size);
 166
 167                         *(u32*)(setup_base + RAMDISK_IMAGE_OFF) = initrd_addr;
 168                         *(u32*)(setup_base + RAMDISK_SIZE_OFF)=initrd_size;
 169                 }
 170         }
 171
 172         if (bootproto >= 0x0201) {
 173                 *(u16*)(setup_base + HEAP_END_PTR_OFF) = HEAP_END_OFFSET;
 174
 175                 /* CAN_USE_HEAP */
 176                 *(u8*)(setup_base + LOADFLAGS_OFF) =
 177                         *(u8*)(setup_base + LOADFLAGS_OFF) | HEAP_FLAG;
 178         }
 179
 180         if (bootproto >= 0x0202) {
 181                 *(u32*)(setup_base + CMD_LINE_PTR_OFF) = (u32)setup_base + COMMAND_LINE_OFFSET;
 182         } else if (bootproto >= 0x0200) {
 183                 *(u16*)(setup_base + CMD_LINE_MAGIC_OFF) = COMMAND_LINE_MAGIC;
 184                 *(u16*)(setup_base + CMD_LINE_OFFSET_OFF) = COMMAND_LINE_OFFSET;
 185                 *(u16*)(setup_base + SETUP_MOVE_SIZE_OFF) = 0x9100;
 186         }
 187
 188
 189         if (big_image) {
 190                 if ((kernel_size - setup_size) > BZIMAGE_MAX_SIZE) {
 191                         printf("Error: bzImage kernel too big! (size: %ld, max: %d)\n",
 192                                kernel_size - setup_size, BZIMAGE_MAX_SIZE);
 193                         return 0;
 194                 }
 195
 196         } else if ((kernel_size - setup_size) > ZIMAGE_MAX_SIZE) {
 197                 printf("Error: zImage kernel too big! (size: %ld, max: %d)\n",
 198                        kernel_size - setup_size, ZIMAGE_MAX_SIZE);
 199                 return 0;
 200         }
 201
 202         /* build command line at COMMAND_LINE_OFFSET */
 203         build_command_line(setup_base + COMMAND_LINE_OFFSET, auto_boot);
 204
 205         printf("Loading %czImage at address 0x%08x (%ld bytes)\n", big_image ? 'b' : ' ',
 206                (u32)load_address, kernel_size - setup_size);
 207
 208
 209         memmove(load_address, image + setup_size, kernel_size - setup_size);
 210
 211         /* ready for booting */
 212         return setup_base;
 213 }
 214
 215 void boot_zimage(void *setup_base)
 216 {
 217         struct pt_regs regs;
 218
 219         memset(&regs, 0, sizeof(struct pt_regs));
 220         regs.xds = (u32)setup_base >> 4;
 221         regs.xss = 0x9000;
 222         regs.esp = 0x9000;
 223         regs.eflags = 0;
 224         enter_realmode(((u32)setup_base+SETUP_START_OFFSET)>>4, 0, &regs, &regs);
 225 }