mirror of
https://github.com/brain-hackers/u-boot-brain
synced 2024-08-19 00:18:51 +09:00
![Wolfgang Denk](/assets/img/avatar_default.png)
The hush shell dynamically allocates (and re-allocates) memory for the argument strings in the "char *argv[]" argument vector passed to commands. Any code that modifies these pointers will cause serious corruption of the malloc data structures and crash U-Boot, so make sure the compiler can check that no such modifications are being done by changing the code into "char * const argv[]". This modification is the result of debugging a strange crash caused after adding a new command, which used the following argument processing code which has been working perfectly fine in all Unix systems since version 6 - but not so in U-Boot: int main (int argc, char **argv) { while (--argc > 0 && **++argv == '-') { /* ====> */ while (*++*argv) { switch (**argv) { case 'd': debug++; break; ... default: usage (); } } } ... } The line marked "====>" will corrupt the malloc data structures and usually cause U-Boot to crash when the next command gets executed by the shell. With the modification, the compiler will prevent this with an error: increment of read-only location '*argv' N.B.: The code above can be trivially rewritten like this: while (--argc > 0 && **++argv == '-') { char *arg = *argv; while (*++arg) { switch (*arg) { ... Signed-off-by: Wolfgang Denk <wd@denx.de> Acked-by: Mike Frysinger <vapier@gentoo.org>
289 lines
7.3 KiB
C
289 lines
7.3 KiB
C
/*
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* (C) Copyright 2002
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* Daniel Engström, Omicron Ceti AB, daniel@omicron.se
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*
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* See file CREDITS for list of people who contributed to this
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* project.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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* MA 02111-1307 USA
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*/
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/*
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* Linux i386 zImage and bzImage loading
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*
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* based on the procdure described in
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* linux/Documentation/i386/boot.txt
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*/
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#include <common.h>
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#include <asm/io.h>
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#include <asm/ptrace.h>
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#include <asm/zimage.h>
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#include <asm/realmode.h>
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#include <asm/byteorder.h>
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#include <asm/bootparam.h>
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#include <asm/ic/sc520.h>
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/*
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* Memory lay-out:
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*
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* relative to setup_base (which is 0x90000 currently)
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*
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* 0x0000-0x7FFF Real mode kernel
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* 0x8000-0x8FFF Stack and heap
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* 0x9000-0x90FF Kernel command line
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*/
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#define DEFAULT_SETUP_BASE 0x90000
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#define COMMAND_LINE_OFFSET 0x9000
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#define HEAP_END_OFFSET 0x8e00
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#define COMMAND_LINE_SIZE 2048
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static void build_command_line(char *command_line, int auto_boot)
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{
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char *env_command_line;
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command_line[0] = '\0';
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env_command_line = getenv("bootargs");
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/* set console= argument if we use a serial console */
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if (NULL == strstr(env_command_line, "console=")) {
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if (0==strcmp(getenv("stdout"), "serial")) {
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/* We seem to use serial console */
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sprintf(command_line, "console=ttyS0,%s ",
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getenv("baudrate"));
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}
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}
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if (auto_boot) {
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strcat(command_line, "auto ");
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}
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if (NULL != env_command_line) {
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strcat(command_line, env_command_line);
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}
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printf("Kernel command line: \"%s\"\n", command_line);
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}
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void *load_zimage(char *image, unsigned long kernel_size,
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unsigned long initrd_addr, unsigned long initrd_size,
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int auto_boot)
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{
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void *setup_base;
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int setup_size;
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int bootproto;
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int big_image;
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void *load_address;
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struct setup_header *hdr = (struct setup_header *)(image + SETUP_SECTS_OFF);
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setup_base = (void*)DEFAULT_SETUP_BASE; /* base address for real-mode segment */
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if (KERNEL_MAGIC != hdr->boot_flag) {
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printf("Error: Invalid Boot Flag (found 0x%04x, expected 0x%04x)\n",
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hdr->boot_flag, KERNEL_MAGIC);
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return 0;
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} else {
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printf("Valid Boot Flag\n");
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}
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/* determine boot protocol version */
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if (KERNEL_V2_MAGIC == hdr->header) {
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printf("Magic signature found\n");
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bootproto = hdr->version;
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} else {
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/* Very old kernel */
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printf("Magic signature not found\n");
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bootproto = 0x0100;
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}
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/* determine size of setup */
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if (0 == hdr->setup_sects) {
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printf("Setup Sectors = 0 (defaulting to 4)\n");
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setup_size = 5 * 512;
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} else {
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setup_size = (hdr->setup_sects + 1) * 512;
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}
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printf("Setup Size = 0x%8.8lx\n", (ulong)setup_size);
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if (setup_size > SETUP_MAX_SIZE) {
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printf("Error: Setup is too large (%d bytes)\n", setup_size);
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}
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/* Determine image type */
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big_image = (bootproto >= 0x0200) && (hdr->loadflags & BIG_KERNEL_FLAG);
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/* Determine load address */
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load_address = (void*)(big_image ? BZIMAGE_LOAD_ADDR : ZIMAGE_LOAD_ADDR);
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/* load setup */
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printf("Moving Real-Mode Code to 0x%8.8lx (%d bytes)\n", (ulong)setup_base, setup_size);
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memmove(setup_base, image, setup_size);
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printf("Using boot protocol version %x.%02x\n",
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(bootproto & 0xff00) >> 8, bootproto & 0xff);
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if (bootproto == 0x0100) {
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*(u16*)(setup_base + CMD_LINE_MAGIC_OFF) = COMMAND_LINE_MAGIC;
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*(u16*)(setup_base + CMD_LINE_OFFSET_OFF) = COMMAND_LINE_OFFSET;
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/* A very old kernel MUST have its real-mode code
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* loaded at 0x90000 */
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if ((u32)setup_base != 0x90000) {
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/* Copy the real-mode kernel */
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memmove((void*)0x90000, setup_base, setup_size);
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/* Copy the command line */
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memmove((void*)0x99000, setup_base+COMMAND_LINE_OFFSET,
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COMMAND_LINE_SIZE);
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setup_base = (void*)0x90000; /* Relocated */
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}
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/* It is recommended to clear memory up to the 32K mark */
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memset((void*)0x90000 + setup_size, 0, SETUP_MAX_SIZE-setup_size);
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}
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/* We are now setting up the real-mode version of the header */
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hdr = (struct setup_header *)(setup_base + SETUP_SECTS_OFF);
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if (bootproto >= 0x0200) {
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hdr->type_of_loader = 8;
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if (hdr->setup_sects >= 15)
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printf("Linux kernel version %s\n", (char *)
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(setup_base + (hdr->kernel_version + 0x200)));
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else
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printf("Setup Sectors < 15 - Cannot print kernel version.\n");
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if (initrd_addr) {
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printf("Initial RAM disk at linear address 0x%08lx, size %ld bytes\n",
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initrd_addr, initrd_size);
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hdr->ramdisk_image = initrd_addr;
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hdr->ramdisk_size = initrd_size;
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}
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}
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if (bootproto >= 0x0201) {
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hdr->heap_end_ptr = HEAP_END_OFFSET;
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hdr->loadflags |= HEAP_FLAG;
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}
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if (bootproto >= 0x0202) {
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hdr->cmd_line_ptr = (u32)setup_base + COMMAND_LINE_OFFSET;
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} else if (bootproto >= 0x0200) {
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*(u16*)(setup_base + CMD_LINE_MAGIC_OFF) = COMMAND_LINE_MAGIC;
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*(u16*)(setup_base + CMD_LINE_OFFSET_OFF) = COMMAND_LINE_OFFSET;
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hdr->setup_move_size = 0x9100;
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}
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if (bootproto >= 0x0204)
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kernel_size = hdr->syssize * 16;
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else
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kernel_size -= setup_size;
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if (big_image) {
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if ((kernel_size) > BZIMAGE_MAX_SIZE) {
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printf("Error: bzImage kernel too big! (size: %ld, max: %d)\n",
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kernel_size, BZIMAGE_MAX_SIZE);
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return 0;
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}
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} else if ((kernel_size) > ZIMAGE_MAX_SIZE) {
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printf("Error: zImage kernel too big! (size: %ld, max: %d)\n",
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kernel_size, ZIMAGE_MAX_SIZE);
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return 0;
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}
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/* build command line at COMMAND_LINE_OFFSET */
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build_command_line(setup_base + COMMAND_LINE_OFFSET, auto_boot);
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printf("Loading %czImage at address 0x%08x (%ld bytes)\n", big_image ? 'b' : ' ',
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(u32)load_address, kernel_size);
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memmove(load_address, image + setup_size, kernel_size);
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/* ready for booting */
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return setup_base;
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}
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void boot_zimage(void *setup_base)
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{
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struct pt_regs regs;
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memset(®s, 0, sizeof(struct pt_regs));
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regs.xds = (u32)setup_base >> 4;
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regs.xes = regs.xds;
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regs.xss = regs.xds;
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regs.esp = 0x9000;
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regs.eflags = 0;
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enter_realmode(((u32)setup_base+SETUP_START_OFFSET)>>4, 0, ®s, ®s);
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}
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int do_zboot (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
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{
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void *base_ptr;
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void *bzImage_addr;
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ulong bzImage_size = 0;
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disable_interrupts();
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/* Setup board for maximum PC/AT Compatibility */
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setup_pcat_compatibility();
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/* argv[1] holds the address of the bzImage */
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bzImage_addr = (void *)simple_strtoul(argv[1], NULL, 16);
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if (argc == 3)
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bzImage_size = simple_strtoul(argv[2], NULL, 16);
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/* Lets look for*/
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base_ptr = load_zimage (bzImage_addr, bzImage_size, 0, 0, 0);
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if (NULL == base_ptr) {
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printf ("## Kernel loading failed ...\n");
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} else {
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printf ("## Transferring control to Linux (at address %08x) ...\n",
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(u32)base_ptr);
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/* we assume that the kernel is in place */
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printf("\nStarting kernel ...\n\n");
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boot_zimage(base_ptr);
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/* does not return */
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}
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return -1;
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}
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U_BOOT_CMD(
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zboot, 3, 0, do_zboot,
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"Boot bzImage",
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""
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);
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