blob: 9938c80a42b327b2e3d5a4fd3aba88de4d3aeffd [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (c) 2011 The Chromium OS Authors.
* (C) Copyright 2002
* Daniel Engström, Omicron Ceti AB, <daniel@omicron.se>
*/
/*
* Linux x86 zImage and bzImage loading
*
* based on the procdure described in
* linux/Documentation/i386/boot.txt
*/
#define LOG_CATEGORY LOGC_BOOT
#include <common.h>
#include <bootm.h>
#include <command.h>
#include <env.h>
#include <init.h>
#include <irq_func.h>
#include <log.h>
#include <malloc.h>
#include <acpi/acpi_table.h>
#include <asm/io.h>
#include <asm/ptrace.h>
#include <asm/zimage.h>
#include <asm/byteorder.h>
#include <asm/bootm.h>
#include <asm/bootparam.h>
#include <asm/global_data.h>
#ifdef CONFIG_SYS_COREBOOT
#include <asm/arch/timestamp.h>
#endif
#include <linux/compiler.h>
#include <linux/ctype.h>
#include <linux/libfdt.h>
DECLARE_GLOBAL_DATA_PTR;
/*
* 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
/**
* struct zboot_state - Current state of the boot
*
* @bzimage_addr: Address of the bzImage to boot
* @bzimage_size: Size of the bzImage, or 0 to detect this
* @initrd_addr: Address of the initial ramdisk, or 0 if none
* @initrd_size: Size of the initial ramdisk, or 0 if none
* @load_address: Address where the bzImage is moved before booting, either
* BZIMAGE_LOAD_ADDR or ZIMAGE_LOAD_ADDR
* @base_ptr: Pointer to the boot parameters, typically at address
* DEFAULT_SETUP_BASE
* @cmdline: Environment variable containing the 'override' command line, or
* NULL to use the one in the setup block
*/
struct zboot_state {
ulong bzimage_addr;
ulong bzimage_size;
ulong initrd_addr;
ulong initrd_size;
ulong load_address;
struct boot_params *base_ptr;
char *cmdline;
} state;
enum {
ZBOOT_STATE_START = BIT(0),
ZBOOT_STATE_LOAD = BIT(1),
ZBOOT_STATE_SETUP = BIT(2),
ZBOOT_STATE_INFO = BIT(3),
ZBOOT_STATE_GO = BIT(4),
/* This one doesn't execute automatically, so stop the count before 5 */
ZBOOT_STATE_DUMP = BIT(5),
ZBOOT_STATE_COUNT = 5,
};
static void build_command_line(char *command_line, int auto_boot)
{
char *env_command_line;
command_line[0] = '\0';
env_command_line = env_get("bootargs");
/* set console= argument if we use a serial console */
if (!strstr(env_command_line, "console=")) {
if (!strcmp(env_get("stdout"), "serial")) {
/* We seem to use serial console */
sprintf(command_line, "console=ttyS0,%s ",
env_get("baudrate"));
}
}
if (auto_boot)
strcat(command_line, "auto ");
if (env_command_line)
strcat(command_line, env_command_line);
#ifdef DEBUG
printf("Kernel command line:");
puts(command_line);
printf("\n");
#endif
}
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, bool verbose)
{
if (hdr->header == KERNEL_V2_MAGIC) {
if (verbose)
printf("Magic signature found\n");
return hdr->version;
} else {
/* Very old kernel */
if (verbose)
printf("Magic signature not found\n");
return 0x0100;
}
}
static int setup_device_tree(struct setup_header *hdr, const void *fdt_blob)
{
int bootproto = get_boot_protocol(hdr, false);
struct setup_data *sd;
int size;
if (bootproto < 0x0209)
return -ENOTSUPP;
if (!fdt_blob)
return 0;
size = fdt_totalsize(fdt_blob);
if (size < 0)
return -EINVAL;
size += sizeof(struct setup_data);
sd = (struct setup_data *)malloc(size);
if (!sd) {
printf("Not enough memory for DTB setup data\n");
return -ENOMEM;
}
sd->next = hdr->setup_data;
sd->type = SETUP_DTB;
sd->len = fdt_totalsize(fdt_blob);
memcpy(sd->data, fdt_blob, sd->len);
hdr->setup_data = (unsigned long)sd;
return 0;
}
static const char *get_kernel_version(struct boot_params *params,
void *kernel_base)
{
struct setup_header *hdr = &params->hdr;
int bootproto;
const char *s, *end;
bootproto = get_boot_protocol(hdr, false);
if (bootproto < 0x0200 || hdr->setup_sects < 15)
return NULL;
/* sanity-check the kernel version in case it is missing */
for (s = kernel_base + hdr->kernel_version + 0x200, end = s + 0x100; *s;
s++) {
if (!isprint(*s))
return NULL;
}
return kernel_base + hdr->kernel_version + 0x200;
}
struct boot_params *load_zimage(char *image, unsigned long kernel_size,
ulong *load_addressp)
{
struct boot_params *setup_base;
const char *version;
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) {
log_warning("Setup Sectors = 0 (defaulting to 4)\n");
setup_size = 5 * 512;
} else {
setup_size = (hdr->setup_sects + 1) * 512;
}
log_debug("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, true);
log_debug("Using boot protocol version %x.%02x\n",
(bootproto & 0xff00) >> 8, bootproto & 0xff);
version = get_kernel_version(params, image);
if (version)
printf("Linux kernel version %s\n", version);
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_addressp = BZIMAGE_LOAD_ADDR;
else
*load_addressp = ZIMAGE_LOAD_ADDR;
printf("Building boot_params at 0x%8.8lx\n", (ulong)setup_base);
memset(setup_base, 0, sizeof(*setup_base));
setup_base->hdr = params->hdr;
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 ((ulong)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 %lx (%ld bytes)\n",
big_image ? "bzImage" : "zImage", *load_addressp, kernel_size);
memmove((void *)*load_addressp, image + setup_size, kernel_size);
return setup_base;
}
int setup_zimage(struct boot_params *setup_base, char *cmd_line, int auto_boot,
ulong initrd_addr, ulong initrd_size, ulong cmdline_force)
{
struct setup_header *hdr = &setup_base->hdr;
int bootproto = get_boot_protocol(hdr, false);
log_debug("Setup E820 entries\n");
if (IS_ENABLED(CONFIG_COREBOOT_SYSINFO)) {
setup_base->e820_entries = cb_install_e820_map(
ARRAY_SIZE(setup_base->e820_map), setup_base->e820_map);
} else {
setup_base->e820_entries = install_e820_map(
ARRAY_SIZE(setup_base->e820_map), setup_base->e820_map);
}
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 = 0x80; /* U-Boot version 0 */
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 (cmd_line) {
int max_size = 0xff;
int ret;
log_debug("Setup cmdline\n");
if (bootproto >= 0x0206)
max_size = hdr->cmdline_size;
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 */
if (cmdline_force)
strcpy(cmd_line, (char *)cmdline_force);
else
build_command_line(cmd_line, auto_boot);
ret = bootm_process_cmdline(cmd_line, max_size, BOOTM_CL_ALL);
if (ret) {
printf("Cmdline setup failed (max_size=%x, bootproto=%x, err=%d)\n",
max_size, bootproto, ret);
return ret;
}
printf("Kernel command line: \"");
puts(cmd_line);
printf("\"\n");
}
if (IS_ENABLED(CONFIG_INTEL_MID) && bootproto >= 0x0207)
hdr->hardware_subarch = X86_SUBARCH_INTEL_MID;
if (IS_ENABLED(CONFIG_GENERATE_ACPI_TABLE))
setup_base->acpi_rsdp_addr = acpi_get_rsdp_addr();
log_debug("Setup devicetree\n");
setup_device_tree(hdr, (const void *)env_get_hex("fdtaddr", 0));
setup_video(&setup_base->screen_info);
if (IS_ENABLED(CONFIG_EFI_STUB))
setup_efi_info(&setup_base->efi_info);
return 0;
}
static int do_zboot_start(struct cmd_tbl *cmdtp, int flag, int argc,
char *const argv[])
{
const char *s;
memset(&state, '\0', sizeof(state));
if (argc >= 2) {
/* argv[1] holds the address of the bzImage */
s = argv[1];
} else {
s = env_get("fileaddr");
}
if (s)
state.bzimage_addr = hextoul(s, NULL);
if (argc >= 3) {
/* argv[2] holds the size of the bzImage */
state.bzimage_size = hextoul(argv[2], NULL);
}
if (argc >= 4)
state.initrd_addr = hextoul(argv[3], NULL);
if (argc >= 5)
state.initrd_size = hextoul(argv[4], NULL);
if (argc >= 6) {
/*
* When the base_ptr is passed in, we assume that the image is
* already loaded at the address given by argv[1] and therefore
* the original bzImage is somewhere else, or not accessible.
* In any case, we don't need access to the bzImage since all
* the processing is assumed to be done.
*
* So set the base_ptr to the given address, use this arg as the
* load address and set bzimage_addr to 0 so we know that it
* cannot be proceesed (or processed again).
*/
state.base_ptr = (void *)hextoul(argv[5], NULL);
state.load_address = state.bzimage_addr;
state.bzimage_addr = 0;
}
if (argc >= 7)
state.cmdline = env_get(argv[6]);
return 0;
}
static int do_zboot_load(struct cmd_tbl *cmdtp, int flag, int argc,
char *const argv[])
{
struct boot_params *base_ptr;
if (state.base_ptr) {
struct boot_params *from = (struct boot_params *)state.base_ptr;
base_ptr = (struct boot_params *)DEFAULT_SETUP_BASE;
log_debug("Building boot_params at 0x%8.8lx\n",
(ulong)base_ptr);
memset(base_ptr, '\0', sizeof(*base_ptr));
base_ptr->hdr = from->hdr;
} else {
base_ptr = load_zimage((void *)state.bzimage_addr, state.bzimage_size,
&state.load_address);
if (!base_ptr) {
puts("## Kernel loading failed ...\n");
return CMD_RET_FAILURE;
}
}
state.base_ptr = base_ptr;
if (env_set_hex("zbootbase", (ulong)base_ptr) ||
env_set_hex("zbootaddr", state.load_address))
return CMD_RET_FAILURE;
return 0;
}
static int do_zboot_setup(struct cmd_tbl *cmdtp, int flag, int argc,
char *const argv[])
{
struct boot_params *base_ptr = state.base_ptr;
int ret;
if (!base_ptr) {
printf("base is not set: use 'zboot load' first\n");
return CMD_RET_FAILURE;
}
ret = setup_zimage(base_ptr, (char *)base_ptr + COMMAND_LINE_OFFSET,
0, state.initrd_addr, state.initrd_size,
(ulong)state.cmdline);
if (ret) {
puts("Setting up boot parameters failed ...\n");
return CMD_RET_FAILURE;
}
return 0;
}
static int do_zboot_info(struct cmd_tbl *cmdtp, int flag, int argc,
char *const argv[])
{
printf("Kernel loaded at %08lx, setup_base=%p\n",
state.load_address, state.base_ptr);
return 0;
}
static int do_zboot_go(struct cmd_tbl *cmdtp, int flag, int argc,
char *const argv[])
{
int ret;
disable_interrupts();
/* we assume that the kernel is in place */
ret = boot_linux_kernel((ulong)state.base_ptr, state.load_address,
false);
printf("Kernel returned! (err=%d)\n", ret);
return CMD_RET_FAILURE;
}
static void print_num(const char *name, ulong value)
{
printf("%-20s: %lx\n", name, value);
}
static void print_num64(const char *name, u64 value)
{
printf("%-20s: %llx\n", name, value);
}
static const char *const e820_type_name[E820_COUNT] = {
[E820_RAM] = "RAM",
[E820_RESERVED] = "Reserved",
[E820_ACPI] = "ACPI",
[E820_NVS] = "ACPI NVS",
[E820_UNUSABLE] = "Unusable",
};
static const char *const bootloader_id[] = {
"LILO",
"Loadlin",
"bootsect-loader",
"Syslinux",
"Etherboot/gPXE/iPXE",
"ELILO",
"undefined",
"GRUB",
"U-Boot",
"Xen",
"Gujin",
"Qemu",
"Arcturus Networks uCbootloader",
"kexec-tools",
"Extended",
"Special",
"Reserved",
"Minimal Linux Bootloader",
"OVMF UEFI virtualization stack",
};
struct flag_info {
uint bit;
const char *name;
};
static struct flag_info load_flags[] = {
{ LOADED_HIGH, "loaded-high" },
{ QUIET_FLAG, "quiet" },
{ KEEP_SEGMENTS, "keep-segments" },
{ CAN_USE_HEAP, "can-use-heap" },
};
static struct flag_info xload_flags[] = {
{ XLF_KERNEL_64, "64-bit-entry" },
{ XLF_CAN_BE_LOADED_ABOVE_4G, "can-load-above-4gb" },
{ XLF_EFI_HANDOVER_32, "32-efi-handoff" },
{ XLF_EFI_HANDOVER_64, "64-efi-handoff" },
{ XLF_EFI_KEXEC, "kexec-efi-runtime" },
};
static void print_flags(struct flag_info *flags, int count, uint value)
{
int i;
printf("%-20s:", "");
for (i = 0; i < count; i++) {
uint mask = flags[i].bit;
if (value & mask)
printf(" %s", flags[i].name);
}
printf("\n");
}
static void show_loader(struct setup_header *hdr)
{
bool version_valid = false;
int type, version;
const char *name;
type = hdr->type_of_loader >> 4;
version = hdr->type_of_loader & 0xf;
if (type == 0xe)
type = 0x10 + hdr->ext_loader_type;
version |= hdr->ext_loader_ver << 4;
if (!hdr->type_of_loader) {
name = "pre-2.00 bootloader";
} else if (hdr->type_of_loader == 0xff) {
name = "unknown";
} else if (type < ARRAY_SIZE(bootloader_id)) {
name = bootloader_id[type];
version_valid = true;
} else {
name = "undefined";
}
printf("%20s %s", "", name);
if (version_valid)
printf(", version %x", version);
printf("\n");
}
void zimage_dump(struct boot_params *base_ptr)
{
struct setup_header *hdr;
const char *version;
int i;
printf("Setup located at %p:\n\n", base_ptr);
print_num64("ACPI RSDP addr", base_ptr->acpi_rsdp_addr);
printf("E820: %d entries\n", base_ptr->e820_entries);
if (base_ptr->e820_entries) {
printf("%18s %16s %s\n", "Addr", "Size", "Type");
for (i = 0; i < base_ptr->e820_entries; i++) {
struct e820_entry *entry = &base_ptr->e820_map[i];
printf("%12llx %10llx %s\n", entry->addr, entry->size,
entry->type < E820_COUNT ?
e820_type_name[entry->type] :
simple_itoa(entry->type));
}
}
hdr = &base_ptr->hdr;
print_num("Setup sectors", hdr->setup_sects);
print_num("Root flags", hdr->root_flags);
print_num("Sys size", hdr->syssize);
print_num("RAM size", hdr->ram_size);
print_num("Video mode", hdr->vid_mode);
print_num("Root dev", hdr->root_dev);
print_num("Boot flag", hdr->boot_flag);
print_num("Jump", hdr->jump);
print_num("Header", hdr->header);
if (hdr->header == KERNEL_V2_MAGIC)
printf("%-20s %s\n", "", "Kernel V2");
else
printf("%-20s %s\n", "", "Ancient kernel, using version 100");
print_num("Version", hdr->version);
print_num("Real mode switch", hdr->realmode_swtch);
print_num("Start sys", hdr->start_sys);
print_num("Kernel version", hdr->kernel_version);
version = get_kernel_version(base_ptr, (void *)state.bzimage_addr);
if (version)
printf(" @%p: %s\n", version, version);
print_num("Type of loader", hdr->type_of_loader);
show_loader(hdr);
print_num("Load flags", hdr->loadflags);
print_flags(load_flags, ARRAY_SIZE(load_flags), hdr->loadflags);
print_num("Setup move size", hdr->setup_move_size);
print_num("Code32 start", hdr->code32_start);
print_num("Ramdisk image", hdr->ramdisk_image);
print_num("Ramdisk size", hdr->ramdisk_size);
print_num("Bootsect kludge", hdr->bootsect_kludge);
print_num("Heap end ptr", hdr->heap_end_ptr);
print_num("Ext loader ver", hdr->ext_loader_ver);
print_num("Ext loader type", hdr->ext_loader_type);
print_num("Command line ptr", hdr->cmd_line_ptr);
if (hdr->cmd_line_ptr) {
printf(" ");
/* Use puts() to avoid limits from CONFIG_SYS_PBSIZE */
puts((char *)(ulong)hdr->cmd_line_ptr);
printf("\n");
}
print_num("Initrd addr max", hdr->initrd_addr_max);
print_num("Kernel alignment", hdr->kernel_alignment);
print_num("Relocatable kernel", hdr->relocatable_kernel);
print_num("Min alignment", hdr->min_alignment);
if (hdr->min_alignment)
printf("%-20s: %x\n", "", 1 << hdr->min_alignment);
print_num("Xload flags", hdr->xloadflags);
print_flags(xload_flags, ARRAY_SIZE(xload_flags), hdr->xloadflags);
print_num("Cmdline size", hdr->cmdline_size);
print_num("Hardware subarch", hdr->hardware_subarch);
print_num64("HW subarch data", hdr->hardware_subarch_data);
print_num("Payload offset", hdr->payload_offset);
print_num("Payload length", hdr->payload_length);
print_num64("Setup data", hdr->setup_data);
print_num64("Pref address", hdr->pref_address);
print_num("Init size", hdr->init_size);
print_num("Handover offset", hdr->handover_offset);
if (get_boot_protocol(hdr, false) >= 0x215)
print_num("Kernel info offset", hdr->kernel_info_offset);
}
static int do_zboot_dump(struct cmd_tbl *cmdtp, int flag, int argc,
char *const argv[])
{
struct boot_params *base_ptr = state.base_ptr;
if (argc > 1)
base_ptr = (void *)hextoul(argv[1], NULL);
if (!base_ptr) {
printf("No zboot setup_base\n");
return CMD_RET_FAILURE;
}
zimage_dump(base_ptr);
return 0;
}
/* Note: This defines the complete_zboot() function */
U_BOOT_SUBCMDS(zboot,
U_BOOT_CMD_MKENT(start, 8, 1, do_zboot_start, "", ""),
U_BOOT_CMD_MKENT(load, 1, 1, do_zboot_load, "", ""),
U_BOOT_CMD_MKENT(setup, 1, 1, do_zboot_setup, "", ""),
U_BOOT_CMD_MKENT(info, 1, 1, do_zboot_info, "", ""),
U_BOOT_CMD_MKENT(go, 1, 1, do_zboot_go, "", ""),
U_BOOT_CMD_MKENT(dump, 2, 1, do_zboot_dump, "", ""),
)
int do_zboot_states(struct cmd_tbl *cmdtp, int flag, int argc,
char *const argv[], int state_mask)
{
int i;
for (i = 0; i < ZBOOT_STATE_COUNT; i++) {
struct cmd_tbl *cmd = &zboot_subcmds[i];
int mask = 1 << i;
int ret;
if (mask & state_mask) {
ret = cmd->cmd(cmd, flag, argc, argv);
if (ret)
return ret;
}
}
return 0;
}
int do_zboot_parent(struct cmd_tbl *cmdtp, int flag, int argc,
char *const argv[], int *repeatable)
{
/* determine if we have a sub command */
if (argc > 1) {
char *endp;
hextoul(argv[1], &endp);
/*
* endp pointing to nul means that argv[1] was just a valid
* number, so pass it along to the normal processing
*/
if (*endp)
return do_zboot(cmdtp, flag, argc, argv, repeatable);
}
do_zboot_states(cmdtp, flag, argc, argv, ZBOOT_STATE_START |
ZBOOT_STATE_LOAD | ZBOOT_STATE_SETUP |
ZBOOT_STATE_INFO | ZBOOT_STATE_GO);
return CMD_RET_FAILURE;
}
U_BOOT_CMDREP_COMPLETE(
zboot, 8, do_zboot_parent, "Boot bzImage",
"[addr] [size] [initrd addr] [initrd size] [setup] [cmdline]\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"
" setup - The address of the kernel setup region, if this\n"
" is not at addr\n"
" cmdline - Environment variable containing the kernel\n"
" command line, to override U-Boot's normal\n"
" cmdline generation\n"
"\n"
"Sub-commands to do part of the zboot sequence:\n"
"\tstart [addr [arg ...]] - specify arguments\n"
"\tload - load OS image\n"
"\tsetup - set up table\n"
"\tinfo - show summary info\n"
"\tgo - start OS\n"
"\tdump [addr] - dump info (optional address of boot params)",
complete_zboot
);