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 unsigned generic_install_e820_map(unsigned max_entries,
  56                                   struct e820entry *entries)
  57 {
  58         return 0;
  59 }
  60
  61 unsigned install_e820_map(unsigned max_entries,
  62                           struct e820entry *entries)
  63         __attribute__((weak, alias("generic_install_e820_map")));
  64
  65 static void build_command_line(char *command_line, int auto_boot)
  66 {
  67         char *env_command_line;
  68
  69         command_line[0] = '\0';
  70
  71         env_command_line =  getenv("bootargs");
  72
  73         /* set console= argument if we use a serial console */
  74         if (!strstr(env_command_line, "console=")) {
  75                 if (!strcmp(getenv("stdout"), "serial")) {
  76
  77                         /* We seem to use serial console */
  78                         sprintf(command_line, "console=ttyS0,%s ",
  79                                 getenv("baudrate"));
  80                 }
  81         }
  82
  83         if (auto_boot)
  84                 strcat(command_line, "auto ");
  85
  86         if (env_command_line)
  87                 strcat(command_line, env_command_line);
  88
  89         printf("Kernel command line: \"%s\"\n", command_line);
  90 }
  91
  92 static int kernel_magic_ok(struct setup_header *hdr)
  93 {
  94         if (KERNEL_MAGIC != hdr->boot_flag) {
  95                 printf("Error: Invalid Boot Flag "
  96                         "(found 0x%04x, expected 0x%04x)\n",
  97                         hdr->boot_flag, KERNEL_MAGIC);
  98                 return 0;
  99         } else {
 100                 printf("Valid Boot Flag\n");
 101                 return 1;
 102         }
 103 }
 104
 105 static int get_boot_protocol(struct setup_header *hdr)
 106 {
 107         if (hdr->header == KERNEL_V2_MAGIC) {
 108                 printf("Magic signature found\n");
 109                 return hdr->version;
 110         } else {
 111                 /* Very old kernel */
 112                 printf("Magic signature not found\n");
 113                 return 0x0100;
 114         }
 115 }
 116
 117 struct boot_params *load_zimage(char *image, unsigned long kernel_size,
 118                                 void **load_address)
 119 {
 120         struct boot_params *setup_base;
 121         int setup_size;
 122         int bootproto;
 123         int big_image;
 124
 125         struct boot_params *params = (struct boot_params *)image;
 126         struct setup_header *hdr = &params->hdr;
 127
 128         /* base address for real-mode segment */
 129         setup_base = (struct boot_params *)DEFAULT_SETUP_BASE;
 130
 131         if (!kernel_magic_ok(hdr))
 132                 return 0;
 133
 134         /* determine size of setup */
 135         if (0 == hdr->setup_sects) {
 136                 printf("Setup Sectors = 0 (defaulting to 4)\n");
 137                 setup_size = 5 * 512;
 138         } else {
 139                 setup_size = (hdr->setup_sects + 1) * 512;
 140         }
 141
 142         printf("Setup Size = 0x%8.8lx\n", (ulong)setup_size);
 143
 144         if (setup_size > SETUP_MAX_SIZE)
 145                 printf("Error: Setup is too large (%d bytes)\n", setup_size);
 146
 147         /* determine boot protocol version */
 148         bootproto = get_boot_protocol(hdr);
 149
 150         printf("Using boot protocol version %x.%02x\n",
 151                (bootproto & 0xff00) >> 8, bootproto & 0xff);
 152
 153         if (bootproto >= 0x0200) {
 154                 if (hdr->setup_sects >= 15) {
 155                         printf("Linux kernel version %s\n",
 156                                 (char *)params +
 157                                 hdr->kernel_version + 0x200);
 158                 } else {
 159                         printf("Setup Sectors < 15 - "
 160                                 "Cannot print kernel version.\n");
 161                 }
 162         }
 163
 164         /* Determine image type */
 165         big_image = (bootproto >= 0x0200) &&
 166                     (hdr->loadflags & BIG_KERNEL_FLAG);
 167
 168         /* Determine load address */
 169         if (big_image)
 170                 *load_address = (void *)BZIMAGE_LOAD_ADDR;
 171         else
 172                 *load_address = (void *)ZIMAGE_LOAD_ADDR;
 173
 174 #if defined CONFIG_ZBOOT_32
 175         printf("Building boot_params at 0x%8.8lx\n", (ulong)setup_base);
 176         memset(setup_base, 0, sizeof(*setup_base));
 177         setup_base->hdr = params->hdr;
 178 #else
 179         /* load setup */
 180         printf("Moving Real-Mode Code to 0x%8.8lx (%d bytes)\n",
 181                (ulong)setup_base, setup_size);
 182         memmove(setup_base, image, setup_size);
 183 #endif
 184
 185         if (bootproto >= 0x0204)
 186                 kernel_size = hdr->syssize * 16;
 187         else
 188                 kernel_size -= setup_size;
 189
 190         if (bootproto == 0x0100) {
 191                 /*
 192                  * A very old kernel MUST have its real-mode code
 193                  * loaded at 0x90000
 194                  */
 195                 if ((u32)setup_base != 0x90000) {
 196                         /* Copy the real-mode kernel */
 197                         memmove((void *)0x90000, setup_base, setup_size);
 198
 199                         /* Copy the command line */
 200                         memmove((void *)0x99000,
 201                                 (u8 *)setup_base + COMMAND_LINE_OFFSET,
 202                                 COMMAND_LINE_SIZE);
 203
 204                          /* Relocated */
 205                         setup_base = (struct boot_params *)0x90000;
 206                 }
 207
 208                 /* It is recommended to clear memory up to the 32K mark */
 209                 memset((u8 *)0x90000 + setup_size, 0,
 210                        SETUP_MAX_SIZE - setup_size);
 211         }
 212
 213         if (big_image) {
 214                 if (kernel_size > BZIMAGE_MAX_SIZE) {
 215                         printf("Error: bzImage kernel too big! "
 216                                 "(size: %ld, max: %d)\n",
 217                                 kernel_size, BZIMAGE_MAX_SIZE);
 218                         return 0;
 219                 }
 220         } else if ((kernel_size) > ZIMAGE_MAX_SIZE) {
 221                 printf("Error: zImage kernel too big! (size: %ld, max: %d)\n",
 222                        kernel_size, ZIMAGE_MAX_SIZE);
 223                 return 0;
 224         }
 225
 226         printf("Loading %s at address %p (%ld bytes)\n",
 227                 big_image ? "bzImage" : "zImage", *load_address, kernel_size);
 228
 229         memmove(*load_address, image + setup_size, kernel_size);
 230
 231         return setup_base;
 232 }
 233
 234 int setup_zimage(struct boot_params *setup_base, char *cmd_line, int auto_boot,
 235                  unsigned long initrd_addr, unsigned long initrd_size)
 236 {
 237         struct setup_header *hdr = &setup_base->hdr;
 238         int bootproto = get_boot_protocol(hdr);
 239
 240 #if defined CONFIG_ZBOOT_32
 241         setup_base->e820_entries = install_e820_map(
 242                 ARRAY_SIZE(setup_base->e820_map), setup_base->e820_map);
 243 #endif
 244
 245         if (bootproto == 0x0100) {
 246                 setup_base->screen_info.cl_magic = COMMAND_LINE_MAGIC;
 247                 setup_base->screen_info.cl_offset = COMMAND_LINE_OFFSET;
 248         }
 249         if (bootproto >= 0x0200) {
 250                 hdr->type_of_loader = 8;
 251
 252                 if (initrd_addr) {
 253                         printf("Initial RAM disk at linear address "
 254                                "0x%08lx, size %ld bytes\n",
 255                                initrd_addr, initrd_size);
 256
 257                         hdr->ramdisk_image = initrd_addr;
 258                         hdr->ramdisk_size = initrd_size;
 259                 }
 260         }
 261
 262         if (bootproto >= 0x0201) {
 263                 hdr->heap_end_ptr = HEAP_END_OFFSET;
 264                 hdr->loadflags |= HEAP_FLAG;
 265         }
 266
 267         if (bootproto >= 0x0202) {
 268                 hdr->cmd_line_ptr = (uintptr_t)cmd_line;
 269         } else if (bootproto >= 0x0200) {
 270                 setup_base->screen_info.cl_magic = COMMAND_LINE_MAGIC;
 271                 setup_base->screen_info.cl_offset =
 272                         (uintptr_t)cmd_line - (uintptr_t)setup_base;
 273
 274                 hdr->setup_move_size = 0x9100;
 275         }
 276
 277         /* build command line at COMMAND_LINE_OFFSET */
 278         build_command_line(cmd_line, auto_boot);
 279         return 0;
 280 }
 281
 282 void boot_zimage(void *setup_base, void *load_address)
 283 {
 284         printf("\nStarting kernel ...\n\n");
 285
 286 #if defined CONFIG_ZBOOT_32
 287         /*
 288          * Set %ebx, %ebp, and %edi to 0, %esi to point to the boot_params
 289          * structure, and then jump to the kernel. We assume that %cs is
 290          * 0x10, 4GB flat, and read/execute, and the data segments are 0x18,
 291          * 4GB flat, and read/write. U-boot is setting them up that way for
 292          * itself in arch/i386/cpu/cpu.c.
 293          */
 294         __asm__ __volatile__ (
 295         "movl $0, %%ebp         \n"
 296         "cli                    \n"
 297         "jmp %[kernel_entry]    \n"
 298         :: [kernel_entry]"a"(load_address),
 299            [boot_params] "S"(setup_base),
 300            "b"(0), "D"(0)
 301         :  "%ebp"
 302         );
 303 #else
 304         struct pt_regs regs;
 305
 306         memset(&regs, 0, sizeof(struct pt_regs));
 307         regs.xds = (u32)setup_base >> 4;
 308         regs.xes = regs.xds;
 309         regs.xss = regs.xds;
 310         regs.esp = 0x9000;
 311         regs.eflags = 0;
 312         enter_realmode(((u32)setup_base + SETUP_START_OFFSET) >> 4, 0,
 313                        &regs, &regs);
 314 #endif
 315 }
 316
 317 void setup_pcat_compatibility(void)
 318         __attribute__((weak, alias("__setup_pcat_compatibility")));
 319
 320 void __setup_pcat_compatibility(void)
 321 {
 322 }
 323
 324 int do_zboot(cmd_tbl_t *cmdtp, int flag, int argc, char *const argv[])
 325 {
 326         struct boot_params *base_ptr;
 327         void *bzImage_addr = NULL;
 328         void *load_address;
 329         char *s;
 330         ulong bzImage_size = 0;
 331         ulong initrd_addr = 0;
 332         ulong initrd_size = 0;
 333
 334         disable_interrupts();
 335
 336         /* Setup board for maximum PC/AT Compatibility */
 337         setup_pcat_compatibility();
 338
 339         if (argc >= 2) {
 340                 /* argv[1] holds the address of the bzImage */
 341                 s = argv[1];
 342         } else {
 343                 s = getenv("fileaddr");
 344         }
 345
 346         if (s)
 347                 bzImage_addr = (void *)simple_strtoul(s, NULL, 16);
 348
 349         if (argc >= 3) {
 350                 /* argv[2] holds the size of the bzImage */
 351                 bzImage_size = simple_strtoul(argv[2], NULL, 16);
 352         }
 353
 354         if (argc >= 4)
 355                 initrd_addr = simple_strtoul(argv[3], NULL, 16);
 356         if (argc >= 5)
 357                 initrd_size = simple_strtoul(argv[4], NULL, 16);
 358
 359         /* Lets look for */
 360         base_ptr = load_zimage(bzImage_addr, bzImage_size, &load_address);
 361
 362         if (!base_ptr) {
 363                 printf("## Kernel loading failed ...\n");
 364                 return -1;
 365         }
 366         if (setup_zimage(base_ptr, (char *)base_ptr + COMMAND_LINE_OFFSET,
 367                         0, initrd_addr, initrd_size)) {
 368                 printf("Setting up boot parameters failed ...\n");
 369                 return -1;
 370         }
 371
 372         printf("## Transferring control to Linux "
 373                "(at address %08x) ...\n",
 374                (u32)base_ptr);
 375
 376         /* we assume that the kernel is in place */
 377         boot_zimage(base_ptr, load_address);
 378         /* does not return */
 379
 380         return -1;
 381 }
 382
 383 U_BOOT_CMD(
 384         zboot, 5, 0,    do_zboot,
 385         "Boot bzImage",
 386         "[addr] [size] [initrd addr] [initrd size]\n"
 387         "      addr -        The optional starting address of the bzimage.\n"
 388         "                    If not set it defaults to the environment\n"
 389         "                    variable \"fileaddr\".\n"
 390         "      size -        The optional size of the bzimage. Defaults to\n"
 391         "                    zero.\n"
 392         "      initrd addr - The address of the initrd image to use, if any.\n"
 393         "      initrd size - The size of the initrd image to use, if any.\n"
 394 );