arch/x86/lib/zimage.c - github/trini/u-boot - Gitiles

 /*
  * Copyright (c) 2011 The Chromium OS Authors.
  * (C) Copyright 2002
  * Daniel Engström, Omicron Ceti AB, <daniel@omicron.se>
  *
  * See file CREDITS for list of people who contributed to this
  * project.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License as
  * published by the Free Software Foundation; either version 2 of
  * the License, or (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  * MA 02111-1307 USA
  */

 /*
  * Linux x86 zImage and bzImage loading
  *
  * based on the procdure described in
  * linux/Documentation/i386/boot.txt
  */

 #include <common.h>
 #include <asm/io.h>
 #include <asm/ptrace.h>
 #include <asm/zimage.h>
 #include <asm/realmode.h>
 #include <asm/byteorder.h>
 #include <asm/bootparam.h>

 /*
  * Memory lay-out:
  *
  * relative to setup_base (which is 0x90000 currently)
  *
  *	0x0000-0x7FFF	Real mode kernel
  *	0x8000-0x8FFF	Stack and heap
  *	0x9000-0x90FF	Kernel command line
  */
 #define DEFAULT_SETUP_BASE	0x90000
 #define COMMAND_LINE_OFFSET	0x9000
 #define HEAP_END_OFFSET		0x8e00

 #define COMMAND_LINE_SIZE	2048

 unsigned generic_install_e820_map(unsigned max_entries,
 				  struct e820entry *entries)
 {
 	return 0;
 }

 unsigned install_e820_map(unsigned max_entries,
 			  struct e820entry *entries)
 	__attribute__((weak, alias("generic_install_e820_map")));

 static void build_command_line(char *command_line, int auto_boot)
 {
 	char *env_command_line;

 	command_line[0] = '\0';

 	env_command_line =  getenv("bootargs");

 	/* set console= argument if we use a serial console */
 	if (!strstr(env_command_line, "console=")) {
 		if (!strcmp(getenv("stdout"), "serial")) {

 			/* We seem to use serial console */
 			sprintf(command_line, "console=ttyS0,%s ",
 				getenv("baudrate"));
 		}
 	}

 	if (auto_boot)
 		strcat(command_line, "auto ");

 	if (env_command_line)
 		strcat(command_line, env_command_line);

 	printf("Kernel command line: \"%s\"\n", command_line);
 }

 static int kernel_magic_ok(struct setup_header *hdr)
 {
 	if (KERNEL_MAGIC != hdr->boot_flag) {
 		printf("Error: Invalid Boot Flag "
 			"(found 0x%04x, expected 0x%04x)\n",
 			hdr->boot_flag, KERNEL_MAGIC);
 		return 0;
 	} else {
 		printf("Valid Boot Flag\n");
 		return 1;
 	}
 }

 static int get_boot_protocol(struct setup_header *hdr)
 {
 	if (hdr->header == KERNEL_V2_MAGIC) {
 		printf("Magic signature found\n");
 		return hdr->version;
 	} else {
 		/* Very old kernel */
 		printf("Magic signature not found\n");
 		return 0x0100;
 	}
 }

 struct boot_params *load_zimage(char *image, unsigned long kernel_size,
 				void **load_address)
 {
 	struct boot_params *setup_base;
 	int setup_size;
 	int bootproto;
 	int big_image;

 	struct boot_params *params = (struct boot_params *)image;
 	struct setup_header *hdr = &params->hdr;

 	/* base address for real-mode segment */
 	setup_base = (struct boot_params *)DEFAULT_SETUP_BASE;

 	if (!kernel_magic_ok(hdr))
 		return 0;

 	/* determine size of setup */
 	if (0 == hdr->setup_sects) {
 		printf("Setup Sectors = 0 (defaulting to 4)\n");
 		setup_size = 5 * 512;
 	} else {
 		setup_size = (hdr->setup_sects + 1) * 512;
 	}

 	printf("Setup Size = 0x%8.8lx\n", (ulong)setup_size);

 	if (setup_size > SETUP_MAX_SIZE)
 		printf("Error: Setup is too large (%d bytes)\n", setup_size);

 	/* determine boot protocol version */
 	bootproto = get_boot_protocol(hdr);

 	printf("Using boot protocol version %x.%02x\n",
 	       (bootproto & 0xff00) >> 8, bootproto & 0xff);

 	if (bootproto >= 0x0200) {
 		if (hdr->setup_sects >= 15) {
 			printf("Linux kernel version %s\n",
 				(char *)params +
 				hdr->kernel_version + 0x200);
 		} else {
 			printf("Setup Sectors < 15 - "
 				"Cannot print kernel version.\n");
 		}
 	}

 	/* Determine image type */
 	big_image = (bootproto >= 0x0200) &&
 		    (hdr->loadflags & BIG_KERNEL_FLAG);

 	/* Determine load address */
 	if (big_image)
 		*load_address = (void *)BZIMAGE_LOAD_ADDR;
 	else
 		*load_address = (void *)ZIMAGE_LOAD_ADDR;

 #if defined CONFIG_ZBOOT_32
 	printf("Building boot_params at 0x%8.8lx\n", (ulong)setup_base);
 	memset(setup_base, 0, sizeof(*setup_base));
 	setup_base->hdr = params->hdr;
 #else
 	/* load setup */
 	printf("Moving Real-Mode Code to 0x%8.8lx (%d bytes)\n",
 	       (ulong)setup_base, setup_size);
 	memmove(setup_base, image, setup_size);
 #endif

 	if (bootproto >= 0x0204)
 		kernel_size = hdr->syssize * 16;
 	else
 		kernel_size -= setup_size;

 	if (bootproto == 0x0100) {
 		/*
 		 * A very old kernel MUST have its real-mode code
 		 * loaded at 0x90000
 		 */
 		if ((u32)setup_base != 0x90000) {
 			/* Copy the real-mode kernel */
 			memmove((void *)0x90000, setup_base, setup_size);

 			/* Copy the command line */
 			memmove((void *)0x99000,
 				(u8 *)setup_base + COMMAND_LINE_OFFSET,
 				COMMAND_LINE_SIZE);

 			 /* Relocated */
 			setup_base = (struct boot_params *)0x90000;
 		}

 		/* It is recommended to clear memory up to the 32K mark */
 		memset((u8 *)0x90000 + setup_size, 0,
 		       SETUP_MAX_SIZE - setup_size);
 	}

 	if (big_image) {
 		if (kernel_size > BZIMAGE_MAX_SIZE) {
 			printf("Error: bzImage kernel too big! "
 				"(size: %ld, max: %d)\n",
 				kernel_size, BZIMAGE_MAX_SIZE);
 			return 0;
 		}
 	} else if ((kernel_size) > ZIMAGE_MAX_SIZE) {
 		printf("Error: zImage kernel too big! (size: %ld, max: %d)\n",
 		       kernel_size, ZIMAGE_MAX_SIZE);
 		return 0;
 	}

 	printf("Loading %s at address %p (%ld bytes)\n",
 		big_image ? "bzImage" : "zImage", *load_address, kernel_size);

 	memmove(*load_address, image + setup_size, kernel_size);

 	return setup_base;
 }

 int setup_zimage(struct boot_params *setup_base, char *cmd_line, int auto_boot,
 		 unsigned long initrd_addr, unsigned long initrd_size)
 {
 	struct setup_header *hdr = &setup_base->hdr;
 	int bootproto = get_boot_protocol(hdr);

 #if defined CONFIG_ZBOOT_32
 	setup_base->e820_entries = install_e820_map(
 		ARRAY_SIZE(setup_base->e820_map), setup_base->e820_map);
 #endif

 	if (bootproto == 0x0100) {
 		setup_base->screen_info.cl_magic = COMMAND_LINE_MAGIC;
 		setup_base->screen_info.cl_offset = COMMAND_LINE_OFFSET;
 	}
 	if (bootproto >= 0x0200) {
 		hdr->type_of_loader = 8;

 		if (initrd_addr) {
 			printf("Initial RAM disk at linear address "
 			       "0x%08lx, size %ld bytes\n",
 			       initrd_addr, initrd_size);

 			hdr->ramdisk_image = initrd_addr;
 			hdr->ramdisk_size = initrd_size;
 		}
 	}

 	if (bootproto >= 0x0201) {
 		hdr->heap_end_ptr = HEAP_END_OFFSET;
 		hdr->loadflags |= HEAP_FLAG;
 	}

 	if (bootproto >= 0x0202) {
 		hdr->cmd_line_ptr = (uintptr_t)cmd_line;
 	} else if (bootproto >= 0x0200) {
 		setup_base->screen_info.cl_magic = COMMAND_LINE_MAGIC;
 		setup_base->screen_info.cl_offset =
 			(uintptr_t)cmd_line - (uintptr_t)setup_base;

 		hdr->setup_move_size = 0x9100;
 	}

 	/* build command line at COMMAND_LINE_OFFSET */
 	build_command_line(cmd_line, auto_boot);
 	return 0;
 }

 void boot_zimage(void *setup_base, void *load_address)
 {
 	printf("\nStarting kernel ...\n\n");

 #if defined CONFIG_ZBOOT_32
 	/*
 	 * Set %ebx, %ebp, and %edi to 0, %esi to point to the boot_params
 	 * structure, and then jump to the kernel. We assume that %cs is
 	 * 0x10, 4GB flat, and read/execute, and the data segments are 0x18,
 	 * 4GB flat, and read/write. U-boot is setting them up that way for
 	 * itself in arch/i386/cpu/cpu.c.
 	 */
 	__asm__ __volatile__ (
 	"movl $0, %%ebp		\n"
 	"cli			\n"
 	"jmp %[kernel_entry]	\n"
 	:: [kernel_entry]"a"(load_address),
 	   [boot_params] "S"(setup_base),
 	   "b"(0), "D"(0)
 	:  "%ebp"
 	);
 #else
 	struct pt_regs regs;

 	memset(&regs, 0, sizeof(struct pt_regs));
 	regs.xds = (u32)setup_base >> 4;
 	regs.xes = regs.xds;
 	regs.xss = regs.xds;
 	regs.esp = 0x9000;
 	regs.eflags = 0;
 	enter_realmode(((u32)setup_base + SETUP_START_OFFSET) >> 4, 0,
 		       &regs, &regs);
 #endif
 }

 int do_zboot(cmd_tbl_t *cmdtp, int flag, int argc, char *const argv[])
 {
 	struct boot_params *base_ptr;
 	void *bzImage_addr = NULL;
 	void *load_address;
 	char *s;
 	ulong bzImage_size = 0;
 	ulong initrd_addr = 0;
 	ulong initrd_size = 0;

 	disable_interrupts();

 	/* Setup board for maximum PC/AT Compatibility */
 	setup_pcat_compatibility();

 	if (argc >= 2) {
 		/* argv[1] holds the address of the bzImage */
 		s = argv[1];
 	} else {
 		s = getenv("fileaddr");
 	}

 	if (s)
 		bzImage_addr = (void *)simple_strtoul(s, NULL, 16);

 	if (argc >= 3) {
 		/* argv[2] holds the size of the bzImage */
 		bzImage_size = simple_strtoul(argv[2], NULL, 16);
 	}

 	if (argc >= 4)
 		initrd_addr = simple_strtoul(argv[3], NULL, 16);
 	if (argc >= 5)
 		initrd_size = simple_strtoul(argv[4], NULL, 16);

 	/* Lets look for */
 	base_ptr = load_zimage(bzImage_addr, bzImage_size, &load_address);

 	if (!base_ptr) {
 		printf("## Kernel loading failed ...\n");
 		return -1;
 	}
 	if (setup_zimage(base_ptr, (char *)base_ptr + COMMAND_LINE_OFFSET,
 			0, initrd_addr, initrd_size)) {
 		printf("Setting up boot parameters failed ...\n");
 		return -1;
 	}

 	printf("## Transferring control to Linux "
 	       "(at address %08x) ...\n",
 	       (u32)base_ptr);

 	/* we assume that the kernel is in place */
 	boot_zimage(base_ptr, load_address);
 	/* does not return */

 	return -1;
 }

 U_BOOT_CMD(
 	zboot, 5, 0,	do_zboot,
 	"Boot bzImage",
 	"[addr] [size] [initrd addr] [initrd size]\n"
 	"      addr -        The optional starting address of the bzimage.\n"
 	"                    If not set it defaults to the environment\n"
 	"                    variable \"fileaddr\".\n"
 	"      size -        The optional size of the bzimage. Defaults to\n"
 	"                    zero.\n"
 	"      initrd addr - The address of the initrd image to use, if any.\n"
 	"      initrd size - The size of the initrd image to use, if any.\n"
 );
	/*
	* Copyright (c) 2011 The Chromium OS Authors.
	* (C) Copyright 2002
	* Daniel Engström, Omicron Ceti AB, <daniel@omicron.se>
	*
	* See file CREDITS for list of people who contributed to this
	* project.
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License as
	* published by the Free Software Foundation; either version 2 of
	* the License, or (at your option) any later version.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, write to the Free Software
	* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
	* MA 02111-1307 USA
	*/

	/*
	* Linux x86 zImage and bzImage loading
	*
	* based on the procdure described in
	* linux/Documentation/i386/boot.txt
	*/

	#include <common.h>
	#include <asm/io.h>
	#include <asm/ptrace.h>
	#include <asm/zimage.h>
	#include <asm/realmode.h>
	#include <asm/byteorder.h>
	#include <asm/bootparam.h>

	/*
	* Memory lay-out:
	*
	* relative to setup_base (which is 0x90000 currently)
	*
	* 0x0000-0x7FFF Real mode kernel
	* 0x8000-0x8FFF Stack and heap
	* 0x9000-0x90FF Kernel command line
	*/
	#define DEFAULT_SETUP_BASE 0x90000
	#define COMMAND_LINE_OFFSET 0x9000
	#define HEAP_END_OFFSET 0x8e00

	#define COMMAND_LINE_SIZE 2048

	unsigned generic_install_e820_map(unsigned max_entries,
	struct e820entry *entries)
	{
	return 0;
	}

	unsigned install_e820_map(unsigned max_entries,
	struct e820entry *entries)
	__attribute__((weak, alias("generic_install_e820_map")));

	static void build_command_line(char *command_line, int auto_boot)
	{
	char *env_command_line;

	command_line[0] = '\0';

	env_command_line = getenv("bootargs");

	/* set console= argument if we use a serial console */
	if (!strstr(env_command_line, "console=")) {
	if (!strcmp(getenv("stdout"), "serial")) {

	/* We seem to use serial console */
	sprintf(command_line, "console=ttyS0,%s ",
	getenv("baudrate"));
	}
	}

	if (auto_boot)
	strcat(command_line, "auto ");

	if (env_command_line)
	strcat(command_line, env_command_line);

	printf("Kernel command line: \"%s\"\n", command_line);
	}

	static int kernel_magic_ok(struct setup_header *hdr)
	{
	if (KERNEL_MAGIC != hdr->boot_flag) {
	printf("Error: Invalid Boot Flag "
	"(found 0x%04x, expected 0x%04x)\n",
	hdr->boot_flag, KERNEL_MAGIC);
	return 0;
	} else {
	printf("Valid Boot Flag\n");
	return 1;
	}
	}

	static int get_boot_protocol(struct setup_header *hdr)
	{
	if (hdr->header == KERNEL_V2_MAGIC) {
	printf("Magic signature found\n");
	return hdr->version;
	} else {
	/* Very old kernel */
	printf("Magic signature not found\n");
	return 0x0100;
	}
	}

	struct boot_params load_zimage(char image, unsigned long kernel_size,
	void **load_address)
	{
	struct boot_params *setup_base;
	int setup_size;
	int bootproto;
	int big_image;

	struct boot_params params = (struct boot_params )image;
	struct setup_header *hdr = &params->hdr;

	/* base address for real-mode segment */
	setup_base = (struct boot_params *)DEFAULT_SETUP_BASE;

	if (!kernel_magic_ok(hdr))
	return 0;

	/* determine size of setup */
	if (0 == hdr->setup_sects) {
	printf("Setup Sectors = 0 (defaulting to 4)\n");
	setup_size = 5 * 512;
	} else {
	setup_size = (hdr->setup_sects + 1) * 512;
	}

	printf("Setup Size = 0x%8.8lx\n", (ulong)setup_size);

	if (setup_size > SETUP_MAX_SIZE)
	printf("Error: Setup is too large (%d bytes)\n", setup_size);

	/* determine boot protocol version */
	bootproto = get_boot_protocol(hdr);

	printf("Using boot protocol version %x.%02x\n",
	(bootproto & 0xff00) >> 8, bootproto & 0xff);

	if (bootproto >= 0x0200) {
	if (hdr->setup_sects >= 15) {
	printf("Linux kernel version %s\n",
	(char *)params +
	hdr->kernel_version + 0x200);
	} else {
	printf("Setup Sectors < 15 - "
	"Cannot print kernel version.\n");
	}
	}

	/* Determine image type */
	big_image = (bootproto >= 0x0200) &&
	(hdr->loadflags & BIG_KERNEL_FLAG);

	/* Determine load address */
	if (big_image)
	load_address = (void )BZIMAGE_LOAD_ADDR;
	else
	load_address = (void )ZIMAGE_LOAD_ADDR;

	#if defined CONFIG_ZBOOT_32
	printf("Building boot_params at 0x%8.8lx\n", (ulong)setup_base);
	memset(setup_base, 0, sizeof(*setup_base));
	setup_base->hdr = params->hdr;
	#else
	/* load setup */
	printf("Moving Real-Mode Code to 0x%8.8lx (%d bytes)\n",
	(ulong)setup_base, setup_size);
	memmove(setup_base, image, setup_size);
	#endif

	if (bootproto >= 0x0204)
	kernel_size = hdr->syssize * 16;
	else
	kernel_size -= setup_size;

	if (bootproto == 0x0100) {
	/*
	* A very old kernel MUST have its real-mode code
	* loaded at 0x90000
	*/
	if ((u32)setup_base != 0x90000) {
	/* Copy the real-mode kernel */
	memmove((void *)0x90000, setup_base, setup_size);

	/* Copy the command line */
	memmove((void *)0x99000,
	(u8 *)setup_base + COMMAND_LINE_OFFSET,
	COMMAND_LINE_SIZE);

	/* Relocated */
	setup_base = (struct boot_params *)0x90000;
	}

	/* It is recommended to clear memory up to the 32K mark */
	memset((u8 *)0x90000 + setup_size, 0,
	SETUP_MAX_SIZE - setup_size);
	}

	if (big_image) {
	if (kernel_size > BZIMAGE_MAX_SIZE) {
	printf("Error: bzImage kernel too big! "
	"(size: %ld, max: %d)\n",
	kernel_size, BZIMAGE_MAX_SIZE);
	return 0;
	}
	} else if ((kernel_size) > ZIMAGE_MAX_SIZE) {
	printf("Error: zImage kernel too big! (size: %ld, max: %d)\n",
	kernel_size, ZIMAGE_MAX_SIZE);
	return 0;
	}

	printf("Loading %s at address %p (%ld bytes)\n",
	big_image ? "bzImage" : "zImage", *load_address, kernel_size);

	memmove(*load_address, image + setup_size, kernel_size);

	return setup_base;
	}

	int setup_zimage(struct boot_params setup_base, char cmd_line, int auto_boot,
	unsigned long initrd_addr, unsigned long initrd_size)
	{
	struct setup_header *hdr = &setup_base->hdr;
	int bootproto = get_boot_protocol(hdr);

	#if defined CONFIG_ZBOOT_32
	setup_base->e820_entries = install_e820_map(
	ARRAY_SIZE(setup_base->e820_map), setup_base->e820_map);
	#endif

	if (bootproto == 0x0100) {
	setup_base->screen_info.cl_magic = COMMAND_LINE_MAGIC;
	setup_base->screen_info.cl_offset = COMMAND_LINE_OFFSET;
	}
	if (bootproto >= 0x0200) {
	hdr->type_of_loader = 8;

	if (initrd_addr) {
	printf("Initial RAM disk at linear address "
	"0x%08lx, size %ld bytes\n",
	initrd_addr, initrd_size);

	hdr->ramdisk_image = initrd_addr;
	hdr->ramdisk_size = initrd_size;
	}
	}

	if (bootproto >= 0x0201) {
	hdr->heap_end_ptr = HEAP_END_OFFSET;
	hdr->loadflags \|= HEAP_FLAG;
	}

	if (bootproto >= 0x0202) {
	hdr->cmd_line_ptr = (uintptr_t)cmd_line;
	} else if (bootproto >= 0x0200) {
	setup_base->screen_info.cl_magic = COMMAND_LINE_MAGIC;
	setup_base->screen_info.cl_offset =
	(uintptr_t)cmd_line - (uintptr_t)setup_base;

	hdr->setup_move_size = 0x9100;
	}

	/* build command line at COMMAND_LINE_OFFSET */
	build_command_line(cmd_line, auto_boot);
	return 0;
	}

	void boot_zimage(void setup_base, void load_address)
	{
	printf("\nStarting kernel ...\n\n");

	#if defined CONFIG_ZBOOT_32
	/*
	* Set %ebx, %ebp, and %edi to 0, %esi to point to the boot_params
	* structure, and then jump to the kernel. We assume that %cs is
	* 0x10, 4GB flat, and read/execute, and the data segments are 0x18,
	* 4GB flat, and read/write. U-boot is setting them up that way for
	* itself in arch/i386/cpu/cpu.c.
	*/
	__asm__ __volatile__ (
	"movl $0, %%ebp \n"
	"cli \n"
	"jmp %[kernel_entry] \n"
	:: [kernel_entry]"a"(load_address),
	[boot_params] "S"(setup_base),
	"b"(0), "D"(0)
	: "%ebp"
	);
	#else
	struct pt_regs regs;

	memset(&regs, 0, sizeof(struct pt_regs));
	regs.xds = (u32)setup_base >> 4;
	regs.xes = regs.xds;
	regs.xss = regs.xds;
	regs.esp = 0x9000;
	regs.eflags = 0;
	enter_realmode(((u32)setup_base + SETUP_START_OFFSET) >> 4, 0,
	&regs, &regs);
	#endif
	}

	int do_zboot(cmd_tbl_t cmdtp, int flag, int argc, char const argv[])
	{
	struct boot_params *base_ptr;
	void *bzImage_addr = NULL;
	void *load_address;
	char *s;
	ulong bzImage_size = 0;
	ulong initrd_addr = 0;
	ulong initrd_size = 0;

	disable_interrupts();

	/* Setup board for maximum PC/AT Compatibility */
	setup_pcat_compatibility();

	if (argc >= 2) {
	/* argv[1] holds the address of the bzImage */
	s = argv[1];
	} else {
	s = getenv("fileaddr");
	}

	if (s)
	bzImage_addr = (void *)simple_strtoul(s, NULL, 16);

	if (argc >= 3) {
	/* argv[2] holds the size of the bzImage */
	bzImage_size = simple_strtoul(argv[2], NULL, 16);
	}

	if (argc >= 4)
	initrd_addr = simple_strtoul(argv[3], NULL, 16);
	if (argc >= 5)
	initrd_size = simple_strtoul(argv[4], NULL, 16);

	/* Lets look for */
	base_ptr = load_zimage(bzImage_addr, bzImage_size, &load_address);

	if (!base_ptr) {
	printf("## Kernel loading failed ...\n");
	return -1;
	}
	if (setup_zimage(base_ptr, (char *)base_ptr + COMMAND_LINE_OFFSET,
	0, initrd_addr, initrd_size)) {
	printf("Setting up boot parameters failed ...\n");
	return -1;
	}

	printf("## Transferring control to Linux "
	"(at address %08x) ...\n",
	(u32)base_ptr);

	/* we assume that the kernel is in place */
	boot_zimage(base_ptr, load_address);
	/* does not return */

	return -1;
	}

	U_BOOT_CMD(
	zboot, 5, 0, do_zboot,
	"Boot bzImage",
	"[addr] [size] [initrd addr] [initrd size]\n"
	" addr - The optional starting address of the bzimage.\n"
	" If not set it defaults to the environment\n"
	" variable \"fileaddr\".\n"
	" size - The optional size of the bzimage. Defaults to\n"
	" zero.\n"
	" initrd addr - The address of the initrd image to use, if any.\n"
	" initrd size - The size of the initrd image to use, if any.\n"
	);