u-boot-brain/arch/x86/lib/zimage.c
Simon Glass 577c4ad055 x86: zimage: Allow dumping the image from outside the module
At present it is possible to dump an image within the zimage command, but
it is also useful to be able to dump it from elsewhere, for example in a
loader that has special handling for the different zimage stages.

Export this feature as a new function.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
2021-02-01 15:33:25 +08:00

780 lines
20 KiB
C

// 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 <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>
#ifdef CONFIG_SYS_COREBOOT
#include <asm/arch/timestamp.h>
#endif
#include <linux/compiler.h>
#include <linux/ctype.h>
#include <linux/libfdt.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
/**
* 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);
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, 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");
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 (err=%d)\n", 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 = simple_strtoul(s, NULL, 16);
if (argc >= 3) {
/* argv[2] holds the size of the bzImage */
state.bzimage_size = simple_strtoul(argv[2], NULL, 16);
}
if (argc >= 4)
state.initrd_addr = simple_strtoul(argv[3], NULL, 16);
if (argc >= 5)
state.initrd_size = simple_strtoul(argv[4], NULL, 16);
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 *)simple_strtoul(argv[5], NULL, 16);
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 *)simple_strtoul(argv[1], NULL, 16);
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;
simple_strtoul(argv[1], &endp, 16);
/*
* 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
);