xref: /illumos-gate/usr/src/boot/common/multiboot2.c (revision b72c8d00)

/*
 * This file and its contents are supplied under the terms of the
 * Common Development and Distribution License ("CDDL"), version 1.0.
 * You may only use this file in accordance with the terms of version
 * 1.0 of the CDDL.
 *
 * A full copy of the text of the CDDL should have accompanied this
 * source.  A copy of the CDDL is also available via the Internet at
 * http://www.illumos.org/license/CDDL.
 */

/*
 * Copyright 2017 Toomas Soome <tsoome@me.com>
 * Copyright 2019, Joyent, Inc.
 */

/*
 * This module adds support for loading and booting illumos multiboot2
 * kernel. This code is only built to support the illumos kernel, it does
 * not support xen.
 */

#include <sys/cdefs.h>
#include <sys/stddef.h>

#include <sys/param.h>
#include <sys/exec.h>
#include <sys/linker.h>
#include <sys/module.h>
#include <sys/stdint.h>
#include <sys/multiboot2.h>
#include <stand.h>
#include <stdbool.h>
#include <machine/elf.h>
#include "libzfs.h"

#include "bootstrap.h"
#include <sys/consplat.h>

#include <machine/metadata.h>
#include <machine/pc/bios.h>

#define	SUPPORT_DHCP
#include <bootp.h>

#if !defined(EFI)
#include "../i386/btx/lib/btxv86.h"
#include "libi386.h"
#include "vbe.h"

#else
#include <efi.h>
#include <efilib.h>
#include "loader_efi.h"

static void (*trampoline)(uint32_t, struct relocator *, uint64_t);
static UINTN efi_map_size;		/* size of efi memory map */
#endif

#include "platform/acfreebsd.h"
#include "acconfig.h"
#define	ACPI_SYSTEM_XFACE
#include "actypes.h"
#include "actbl.h"

extern ACPI_TABLE_RSDP *rsdp;

/* MB data heap pointer. */
static vm_offset_t last_addr;

static int multiboot2_loadfile(char *, uint64_t, struct preloaded_file **);
static int multiboot2_exec(struct preloaded_file *);

struct file_format multiboot2 = { multiboot2_loadfile, multiboot2_exec };
static bool keep_bs = false;
static bool have_framebuffer = false;
static vm_offset_t load_addr;
static vm_offset_t entry_addr;
bool has_boot_services = true;

/*
 * Validate tags in info request. This function is provided just to
 * recognize the current tag list and only serves as a limited
 * safe guard against possibly corrupt information.
 */
static bool
is_info_request_valid(multiboot_header_tag_information_request_t *rtag)
{
	int i;

	/*
	 * If the tag is optional and we do not support it, we do not
	 * have to do anything special, so we skip optional tags.
	 */
	if (rtag->mbh_flags & MULTIBOOT_HEADER_TAG_OPTIONAL)
		return (true);

	for (i = 0; i < (rtag->mbh_size - sizeof (*rtag)) /
	    sizeof (rtag->mbh_requests[0]); i++)
		switch (rtag->mbh_requests[i]) {
		case MULTIBOOT_TAG_TYPE_END:
		case MULTIBOOT_TAG_TYPE_CMDLINE:
		case MULTIBOOT_TAG_TYPE_BOOT_LOADER_NAME:
		case MULTIBOOT_TAG_TYPE_MODULE:
		case MULTIBOOT_TAG_TYPE_BASIC_MEMINFO:
		case MULTIBOOT_TAG_TYPE_BOOTDEV:
		case MULTIBOOT_TAG_TYPE_MMAP:
		case MULTIBOOT_TAG_TYPE_FRAMEBUFFER:
		case MULTIBOOT_TAG_TYPE_VBE:
		case MULTIBOOT_TAG_TYPE_ELF_SECTIONS:
		case MULTIBOOT_TAG_TYPE_APM:
		case MULTIBOOT_TAG_TYPE_EFI32:
		case MULTIBOOT_TAG_TYPE_EFI64:
		case MULTIBOOT_TAG_TYPE_ACPI_OLD:
		case MULTIBOOT_TAG_TYPE_ACPI_NEW:
		case MULTIBOOT_TAG_TYPE_NETWORK:
		case MULTIBOOT_TAG_TYPE_EFI_MMAP:
		case MULTIBOOT_TAG_TYPE_EFI_BS:
		case MULTIBOOT_TAG_TYPE_EFI32_IH:
		case MULTIBOOT_TAG_TYPE_EFI64_IH:
		case MULTIBOOT_TAG_TYPE_LOAD_BASE_ADDR:
			break;
		default:
			printf("unsupported information tag: 0x%x\n",
			    rtag->mbh_requests[i]);
			return (false);
		}
	return (true);
}

static int
multiboot2_loadfile(char *filename, uint64_t dest,
    struct preloaded_file **result)
{
	int fd, error;
	uint32_t i;
	struct stat st;
	caddr_t header_search;
	multiboot2_header_t *header;
	multiboot_header_tag_t *tag;
	multiboot_header_tag_address_t *addr_tag = NULL;
	multiboot_header_tag_entry_address_t *entry_tag = NULL;
	struct preloaded_file *fp;

	/* This allows to check other file formats from file_formats array. */
	error = EFTYPE;
	if (filename == NULL)
		return (error);

	/* is kernel already loaded? */
	fp = file_findfile(NULL, NULL);
	if (fp != NULL)
		return (error);

	if ((fd = open(filename, O_RDONLY)) == -1)
		return (errno);

	/*
	 * Read MULTIBOOT_SEARCH size in order to search for the
	 * multiboot magic header.
	 */
	header_search = malloc(MULTIBOOT_SEARCH);
	if (header_search == NULL) {
		close(fd);
		return (ENOMEM);
	}

	if (read(fd, header_search, MULTIBOOT_SEARCH) != MULTIBOOT_SEARCH)
		goto out;

	header = NULL;
	for (i = 0; i <= (MULTIBOOT_SEARCH - sizeof (multiboot2_header_t));
	    i += MULTIBOOT_HEADER_ALIGN) {
		header = (multiboot2_header_t *)(header_search + i);

		/* Do we have match on magic? */
		if (header->mb2_magic != MULTIBOOT2_HEADER_MAGIC) {
			header = NULL;
			continue;
		}
		/*
		 * Validate checksum, the sum of magic + architecture +
		 * header_length + checksum must equal 0.
		 */
		if (header->mb2_magic + header->mb2_architecture +
		    header->mb2_header_length + header->mb2_checksum != 0) {
			header = NULL;
			continue;
		}
		/*
		 * Finally, the entire header must fit within MULTIBOOT_SEARCH.
		 */
		if (i + header->mb2_header_length > MULTIBOOT_SEARCH) {
			header = NULL;
			continue;
		}
		break;
	}

	if (header == NULL)
		goto out;

	have_framebuffer = false;
	for (tag = header->mb2_tags; tag->mbh_type != MULTIBOOT_TAG_TYPE_END;
	    tag = (multiboot_header_tag_t *)((uintptr_t)tag +
	    roundup2(tag->mbh_size, MULTIBOOT_TAG_ALIGN))) {
		switch (tag->mbh_type) {
		case MULTIBOOT_HEADER_TAG_INFORMATION_REQUEST:
			if (is_info_request_valid((void*)tag) == false)
				goto out;
			break;
		case MULTIBOOT_HEADER_TAG_ADDRESS:
			addr_tag = (multiboot_header_tag_address_t *)tag;
			break;
		case MULTIBOOT_HEADER_TAG_ENTRY_ADDRESS:
			entry_tag =
			    (multiboot_header_tag_entry_address_t *)tag;
			break;
		case MULTIBOOT_HEADER_TAG_CONSOLE_FLAGS:
			break;
		case MULTIBOOT_HEADER_TAG_FRAMEBUFFER:
			have_framebuffer = true;
			break;
		case MULTIBOOT_HEADER_TAG_MODULE_ALIGN:
			/* we always align modules */
			break;
		case MULTIBOOT_HEADER_TAG_EFI_BS:
			keep_bs = true;
			break;
		default:
			if (!(tag->mbh_flags & MULTIBOOT_HEADER_TAG_OPTIONAL)) {
				printf("unsupported tag: 0x%x\n",
				    tag->mbh_type);
				goto out;
			}
		}
	}

	/*
	 * We must have addr_tag and entry_tag to load a 64-bit kernel.
	 * If these tags are missing, we either have a 32-bit kernel, or
	 * this is not our kernel at all.
	 */
	if (addr_tag != NULL && entry_tag != NULL) {
		fp = file_alloc();
		if (fp == NULL) {
			error = ENOMEM;
			goto out;
		}
		if (lseek(fd, 0, SEEK_SET) == -1) {
			printf("lseek failed\n");
			error = EIO;
			file_discard(fp);
			goto out;
		}
		if (fstat(fd, &st) < 0) {
			printf("fstat failed\n");
			error = EIO;
			file_discard(fp);
			goto out;
		}

		load_addr = addr_tag->mbh_load_addr;
		entry_addr = entry_tag->mbh_entry_addr;
		fp->f_addr = archsw.arch_loadaddr(LOAD_KERN, filename,
		    addr_tag->mbh_load_addr);
		if (fp->f_addr == 0) {
			error = ENOMEM;
			file_discard(fp);
			goto out;
		}
		fp->f_size = archsw.arch_readin(fd, fp->f_addr, st.st_size);

		if (fp->f_size != st.st_size) {
			printf("error reading %s: %s\n", filename,
			    strerror(errno));
			file_discard(fp);
			error = EIO;
			goto out;
		}

		fp->f_name = strdup(filename);
		fp->f_type = strdup("aout multiboot2 kernel");
		if (fp->f_name == NULL || fp->f_type == NULL) {
			error = ENOMEM;
			file_discard(fp);
			goto out;
		}

		fp->f_metadata = NULL;
		error = 0;
	} else {
#if defined(EFI)
		/* 32-bit kernel is not yet supported for EFI */
		printf("32-bit kernel is not supported by UEFI loader\n");
		error = ENOTSUP;
		goto out;
#endif
		/* elf32_loadfile_raw will fill the attributes in fp. */
		error = elf32_loadfile_raw(filename, dest, &fp, 2);
		if (error != 0) {
			printf("elf32_loadfile_raw failed: %d unable to "
			    "load multiboot2 kernel\n", error);
			goto out;
		}
		entry_addr = fp->f_addr;
		/*
		 * We want the load_addr to have some legal value,
		 * so we set it same as the entry_addr.
		 * The distinction is important with UEFI, but not
		 * with BIOS version, because BIOS version does not use
		 * staging area.
		 */
		load_addr = fp->f_addr;
	}

	setenv("kernelname", fp->f_name, 1);
#if defined(EFI)
	efi_addsmapdata(fp);
#else
	bios_addsmapdata(fp);
#endif
	*result = fp;
out:
	free(header_search);
	close(fd);
	return (error);
}

/*
 * Search the command line for named property.
 *
 * Return codes:
 *	0	The name is found, we return the data in value and len.
 *	ENOENT	The name is not found.
 *	EINVAL	The provided command line is badly formed.
 */
static int
find_property_value(const char *cmd, const char *name, const char **value,
    size_t *len)
{
	const char *namep, *valuep;
	size_t name_len, value_len;
	int quoted;

	*value = NULL;
	*len = 0;

	if (cmd == NULL)
		return (ENOENT);

	while (*cmd != '\0') {
		if (cmd[0] != '-' || cmd[1] != 'B') {
			cmd++;
			continue;
		}
		cmd += 2;	/* Skip -B */
		while (cmd[0] == ' ' || cmd[0] == '\t')
			cmd++;	/* Skip whitespaces. */
		while (*cmd != '\0' && cmd[0] != ' ' && cmd[0] != '\t') {
			namep = cmd;
			valuep = strchr(cmd, '=');
			if (valuep == NULL)
				break;
			name_len = valuep - namep;
			valuep++;
			value_len = 0;
			quoted = 0;
			for (;; ++value_len) {
				if (valuep[value_len] == '\0')
					break;

				/* Is this value quoted? */
				if (value_len == 0 &&
				    (valuep[0] == '\'' || valuep[0] == '"')) {
					quoted = valuep[0];
					++value_len;
				}

				/*
				 * In the quote accept any character,
				 * but look for ending quote.
				 */
				if (quoted != 0) {
					if (valuep[value_len] == quoted)
						quoted = 0;
					continue;
				}

				/* A comma or white space ends the value. */
				if (valuep[value_len] == ',' ||
				    valuep[value_len] == ' ' ||
				    valuep[value_len] == '\t')
					break;
			}
			if (quoted != 0) {
				printf("Missing closing '%c' in \"%s\"\n",
				    quoted, valuep);
				return (EINVAL);
			}
			if (value_len != 0) {
				if (strncmp(namep, name, name_len) == 0) {
					*value = valuep;
					*len = value_len;
					return (0);
				}
			}
			cmd = valuep + value_len;
			while (*cmd == ',')
				cmd++;
		}
	}
	return (ENOENT);
}

/*
 * If command line has " -B ", insert property after "-B ", otherwise
 * append to command line.
 */
static char *
insert_cmdline(const char *head, const char *prop)
{
	const char *prop_opt = " -B ";
	char *cmdline, *tail;
	int len = 0;

	tail = strstr(head, prop_opt);
	if (tail != NULL) {
		ptrdiff_t diff;
		tail += strlen(prop_opt);
		diff = tail - head;
		if (diff >= INT_MAX)
			return (NULL);
		len = (int)diff;
	}

	if (tail == NULL)
		asprintf(&cmdline, "%s%s%s", head, prop_opt, prop);
	else
		asprintf(&cmdline, "%.*s%s,%s", len, head, prop, tail);

	return (cmdline);
}

/*
 * Since we have no way to pass the environment to the mb1 kernel other than
 * through arguments, we need to take care of console setup.
 *
 * If the console is in mirror mode, set the kernel console from $os_console.
 * If it's unset, use first item from $console.
 * If $console is "ttyX", also pass $ttyX-mode, since it may have been set by
 * the user.
 *
 * In case of memory allocation errors, just return the original command line
 * so we have a chance of booting.
 *
 * On success, cl will be freed and a new, allocated command line string is
 * returned.
 *
 * For the mb2 kernel, we only set command line console if os_console is set.
 * We can not overwrite console in the environment, as it can disrupt the
 * loader console messages, and we do not want to deal with the os_console
 * in the kernel.
 */
static char *
update_cmdline(char *cl, bool mb2)
{
	char *os_console = getenv("os_console");
	char *ttymode = NULL;
	char mode[10];
	char *tmp;
	const char *prop;
	size_t plen;
	int rv;

	if (mb2 == true && os_console == NULL)
		return (cl);

	if (os_console == NULL) {
		tmp = strdup(getenv("console"));
		os_console = strsep(&tmp, ", ");
	} else {
		os_console = strdup(os_console);
	}

	if (os_console == NULL)
		return (cl);

	if (mb2 == false && strncmp(os_console, "tty", 3) == 0) {
		snprintf(mode, sizeof (mode), "%s-mode", os_console);
		/*
		 * The ttyX-mode variable is set by our serial console
		 * driver for ttya-ttyd. However, since the os_console
		 * values are not verified, it is possible we get bogus
		 * name and no mode variable. If so, we do not set console
		 * property and let the kernel use defaults.
		 */
		if ((ttymode = getenv(mode)) == NULL)
			return (cl);
	}

	rv = find_property_value(cl, "console", &prop, &plen);
	if (rv != 0 && rv != ENOENT) {
		free(os_console);
		return (cl);
	}

	/* If console is set and this is MB2 boot, we are done. */
	if (rv == 0 && mb2 == true) {
		free(os_console);
		return (cl);
	}

	/* If console is set, do we need to set tty mode? */
	if (rv == 0) {
		const char *ttyp = NULL;
		size_t ttylen;

		free(os_console);
		os_console = NULL;
		*mode = '\0';
		if (strncmp(prop, "tty", 3) == 0 && plen == 4) {
			strncpy(mode, prop, plen);
			mode[plen] = '\0';
			strncat(mode, "-mode", 5);
			find_property_value(cl, mode, &ttyp, &ttylen);
		}

		if (*mode != '\0' && ttyp == NULL)
			ttymode = getenv(mode);
		else
			return (cl);
	}

	/* Build updated command line. */
	if (os_console != NULL) {
		char *propstr;

		asprintf(&propstr, "console=%s", os_console);
		free(os_console);
		if (propstr == NULL) {
			return (cl);
		}

		tmp = insert_cmdline(cl, propstr);
		free(propstr);
		if (tmp == NULL)
			return (cl);

		free(cl);
		cl = tmp;
	}
	if (ttymode != NULL) {
		char *propstr;

		asprintf(&propstr, "%s=\"%s\"", mode, ttymode);
		if (propstr == NULL)
			return (cl);

		tmp = insert_cmdline(cl, propstr);
		free(propstr);
		if (tmp == NULL)
			return (cl);
		free(cl);
		cl = tmp;
	}

	return (cl);
}

/*
 * Build the kernel command line. Shared function between MB1 and MB2.
 *
 * In both cases, if fstype is set and is not zfs, we do not set up
 * zfs-bootfs property. But we set kernel file name and options.
 *
 * For the MB1, we only can pass properties on command line, so
 * we will set console, ttyX-mode (for serial console) and zfs-bootfs.
 *
 * For the MB2, we can pass properties in environment, but if os_console
 * is set in environment, we need to add console property on the kernel
 * command line.
 *
 * The console properties are managed in update_cmdline().
 */
int
mb_kernel_cmdline(struct preloaded_file *fp, struct devdesc *rootdev,
    char **line)
{
	const char *fs = getenv("fstype");
	char *cmdline;
	size_t len;
	bool zfs_root = false;
	bool mb2;
	int rv;

	/*
	 * With multiple console devices and "os_console" variable not
	 * set, set os_console to last input device.
	 */
	rv = cons_inputdev();
	if (rv != -1)
		(void) setenv("os_console", consoles[rv]->c_name, 0);

	/*
	 * 64-bit kernel has aout header, 32-bit kernel is elf, and the
	 * type strings are different. Lets just search for "multiboot2".
	 */
	if (strstr(fp->f_type, "multiboot2") == NULL)
		mb2 = false;
	else
		mb2 = true;

	if (rootdev->d_dev->dv_type == DEVT_ZFS)
		zfs_root = true;

	/* If we have fstype set in env, reset zfs_root if needed. */
	if (fs != NULL && strcmp(fs, "zfs") != 0)
		zfs_root = false;

	/*
	 * If we have fstype set on the command line,
	 * reset zfs_root if needed.
	 */
	rv = find_property_value(fp->f_args, "fstype", &fs, &len);
	if (rv != 0 && rv != ENOENT)
		return (rv);

	if (fs != NULL && strncmp(fs, "zfs", len) != 0)
		zfs_root = false;

	/* zfs_bootfs() will set the environment, it must be called. */
	if (zfs_root == true)
		fs = zfs_bootfs(rootdev);

	if (fp->f_args == NULL)
		cmdline = strdup(fp->f_name);
	else
		asprintf(&cmdline, "%s %s", fp->f_name, fp->f_args);

	if (cmdline == NULL)
		return (ENOMEM);

	/* Append zfs-bootfs for MB1 command line. */
	if (mb2 == false && zfs_root == true) {
		char *tmp;

		tmp = insert_cmdline(cmdline, fs);
		free(cmdline);
		if (tmp == NULL)
			return (ENOMEM);
		cmdline = tmp;
	}

	*line = update_cmdline(cmdline, mb2);
	return (0);
}

/*
 * Returns allocated virtual address from MB info area.
 */
static vm_offset_t
mb_malloc(size_t n)
{
	vm_offset_t ptr = last_addr;
	last_addr = roundup(last_addr + n, MULTIBOOT_TAG_ALIGN);
	return (ptr);
}

/*
 * Calculate size for module tag list.
 */
static size_t
module_size(struct preloaded_file *fp)
{
	size_t len, size;
	struct preloaded_file *mfp;

	size = 0;
	for (mfp = fp->f_next; mfp != NULL; mfp = mfp->f_next) {
		len = strlen(mfp->f_name) + 1;
		len += strlen(mfp->f_type) + 5 + 1; /* 5 is for "type=" */
		if (mfp->f_args != NULL)
			len += strlen(mfp->f_args) + 1;
		size += sizeof (multiboot_tag_module_t) + len;
		size = roundup(size, MULTIBOOT_TAG_ALIGN);
	}
	return (size);
}

#if defined(EFI)
/*
 * Calculate size for UEFI memory map tag.
 */
#define	EFI_EXTRA_PAGES	3

static int
efimemmap_size(void)
{
	UINTN size, cur_size, desc_size;
	EFI_MEMORY_DESCRIPTOR *mmap;
	EFI_STATUS ret;

	size = EFI_PAGE_SIZE;		/* Start with 4k. */
	while (1) {
		cur_size = size;
		mmap = malloc(cur_size);
		if (mmap == NULL)
			return (0);
		ret = BS->GetMemoryMap(&cur_size, mmap, NULL, &desc_size, NULL);
		free(mmap);
		if (ret == EFI_SUCCESS)
			break;
		if (ret == EFI_BUFFER_TOO_SMALL) {
			if (size < cur_size)
				size = cur_size;
			size += (EFI_PAGE_SIZE);
		} else
			return (0);
	}

	/* EFI MMAP will grow when we allocate MBI, set some buffer. */
	size += (EFI_EXTRA_PAGES << EFI_PAGE_SHIFT);
	size = roundup2(size, EFI_PAGE_SIZE);
	efi_map_size = size;	/* Record the calculated size. */
	return (sizeof (multiboot_tag_efi_mmap_t) + size);
}
#endif

/*
 * Calculate size for bios smap tag.
 */
static size_t
biossmap_size(struct preloaded_file *fp)
{
	int num;
	struct file_metadata *md;

	md = file_findmetadata(fp, MODINFOMD_SMAP);
	if (md == NULL)
		return (0);

	num = md->md_size / sizeof (struct bios_smap); /* number of entries */
	return (sizeof (multiboot_tag_mmap_t) +
	    num * sizeof (multiboot_mmap_entry_t));
}

static size_t
mbi_size(struct preloaded_file *fp, char *cmdline)
{
	size_t size;
#if !defined(EFI)
	extern multiboot_tag_framebuffer_t gfx_fb;
#endif

	size = sizeof (uint32_t) * 2; /* first 2 fields from MBI header */
	size += sizeof (multiboot_tag_string_t) + strlen(cmdline) + 1;
	size = roundup2(size, MULTIBOOT_TAG_ALIGN);
	size += sizeof (multiboot_tag_string_t) + strlen(bootprog_info) + 1;
	size = roundup2(size, MULTIBOOT_TAG_ALIGN);
#if !defined(EFI)
	size += sizeof (multiboot_tag_basic_meminfo_t);
	size = roundup2(size, MULTIBOOT_TAG_ALIGN);
#endif
	size += module_size(fp);
	size = roundup2(size, MULTIBOOT_TAG_ALIGN);
#if defined(EFI)
	size += sizeof (multiboot_tag_efi64_t);
	size = roundup2(size, MULTIBOOT_TAG_ALIGN);
	size += efimemmap_size();
	size = roundup2(size, MULTIBOOT_TAG_ALIGN);

	if (have_framebuffer == true) {
		size += sizeof (multiboot_tag_framebuffer_t);
		size = roundup2(size, MULTIBOOT_TAG_ALIGN);
	}
#endif

	size += biossmap_size(fp);
	size = roundup2(size, MULTIBOOT_TAG_ALIGN);

#if !defined(EFI)
	if (gfx_fb.framebuffer_common.framebuffer_type ==
	    MULTIBOOT_FRAMEBUFFER_TYPE_INDEXED) {
		size += sizeof (struct multiboot_tag_framebuffer_common);
		size += CMAP_SIZE * sizeof (multiboot_color_t);
	} else {
		size += sizeof (multiboot_tag_framebuffer_t);
	}
	size = roundup2(size, MULTIBOOT_TAG_ALIGN);

	size += sizeof (multiboot_tag_vbe_t);
	size = roundup2(size, MULTIBOOT_TAG_ALIGN);
#endif

	if (bootp_response != NULL) {
		size += sizeof (multiboot_tag_network_t) + bootp_response_size;
		size = roundup2(size, MULTIBOOT_TAG_ALIGN);
	}

	if (rsdp != NULL) {
		if (rsdp->Revision == 0) {
			size += sizeof (multiboot_tag_old_acpi_t) +
			    sizeof (ACPI_RSDP_COMMON);
		} else {
			size += sizeof (multiboot_tag_new_acpi_t) +
			    rsdp->Length;
		}
		size = roundup2(size, MULTIBOOT_TAG_ALIGN);
	}
	size += sizeof (multiboot_tag_t);

	return (size);
}

#if defined(EFI)
static bool
overlaps(uintptr_t start1, size_t size1, uintptr_t start2, size_t size2)
{
	if (start1 < start2 + size2 &&
	    start1 + size1 >= start2) {
		printf("overlaps: %zx-%zx, %zx-%zx\n",
		    start1, start1 + size1, start2, start2 + size2);
		return (true);
	}

	return (false);
}
#endif

static int
multiboot2_exec(struct preloaded_file *fp)
{
	multiboot2_info_header_t *mbi = NULL;
	struct preloaded_file *mfp;
	char *cmdline = NULL;
	struct devdesc *rootdev;
	struct file_metadata *md;
	int i, error, num;
	int rootfs = 0;
	size_t size;
	struct bios_smap *smap;
#if defined(EFI)
	multiboot_tag_module_t *module, *mp;
	struct relocator *relocator = NULL;
	EFI_MEMORY_DESCRIPTOR *map;
	UINTN map_size, desc_size;
	struct chunk_head *head;
	struct chunk *chunk;
	vm_offset_t tmp;

	efi_getdev((void **)(&rootdev), NULL, NULL);

	/*
	 * We need 5 pages for relocation. We'll allocate from the heap: while
	 * it's possible that our heap got placed low down enough to be in the
	 * way of where we're going to relocate our kernel, it's hopefully not
	 * likely.
	 */
	if ((relocator = malloc(EFI_PAGE_SIZE * 5)) == NULL) {
		printf("relocator malloc failed!\n");
		error = ENOMEM;
		goto error;
	}

	if (overlaps((uintptr_t)relocator, EFI_PAGE_SIZE * 5,
	    load_addr, fp->f_size)) {
		printf("relocator pages overlap the kernel!\n");
		error = EINVAL;
		goto error;
	}

#else
	i386_getdev((void **)(&rootdev), NULL, NULL);

	if (have_framebuffer == false) {
		/* make sure we have text mode */
		bios_set_text_mode(VGA_TEXT_MODE);
	}
#endif

	error = EINVAL;
	if (rootdev == NULL) {
		printf("can't determine root device\n");
		goto error;
	}

	/*
	 * Set the image command line.
	 */
	if (fp->f_args == NULL) {
		cmdline = getenv("boot-args");
		if (cmdline != NULL) {
			fp->f_args = strdup(cmdline);
			if (fp->f_args == NULL) {
				error = ENOMEM;
				goto error;
			}
		}
	}

	error = mb_kernel_cmdline(fp, rootdev, &cmdline);
	if (error != 0)
		goto error;

	/* mb_kernel_cmdline() updates the environment. */
	build_environment_module();

	/* Pass the loaded console font for kernel. */
	build_font_module();

	size = mbi_size(fp, cmdline);	/* Get the size for MBI. */

	/* Set up the base for mb_malloc. */
	i = 0;
	for (mfp = fp; mfp->f_next != NULL; mfp = mfp->f_next)
		i++;

#if defined(EFI)
	/* We need space for kernel + MBI + # modules */
	num = (EFI_PAGE_SIZE - offsetof(struct relocator, rel_chunklist)) /
	    sizeof (struct chunk);
	if (i + 2 >= num) {
		printf("Too many modules, do not have space for relocator.\n");
		error = ENOMEM;
		goto error;
	}

	last_addr = efi_loadaddr(LOAD_MEM, &size, mfp->f_addr + mfp->f_size);
	mbi = (multiboot2_info_header_t *)last_addr;
	if (mbi == NULL) {
		error = ENOMEM;
		goto error;
	}
	last_addr = (vm_offset_t)mbi->mbi_tags;
#else
	/* Start info block from the new page. */
	last_addr = i386_loadaddr(LOAD_MEM, &size, mfp->f_addr + mfp->f_size);

	/* Do we have space for multiboot info? */
	if (last_addr + size >= memtop_copyin) {
		error = ENOMEM;
		goto error;
	}

	mbi = (multiboot2_info_header_t *)PTOV(last_addr);
	last_addr = (vm_offset_t)mbi->mbi_tags;
#endif	/* EFI */

	{
		multiboot_tag_string_t *tag;
		i = sizeof (multiboot_tag_string_t) + strlen(cmdline) + 1;
		tag = (multiboot_tag_string_t *)mb_malloc(i);

		tag->mb_type = MULTIBOOT_TAG_TYPE_CMDLINE;
		tag->mb_size = i;
		memcpy(tag->mb_string, cmdline, strlen(cmdline) + 1);
		free(cmdline);
		cmdline = NULL;
	}

	{
		multiboot_tag_string_t *tag;
		i = sizeof (multiboot_tag_string_t) + strlen(bootprog_info) + 1;
		tag = (multiboot_tag_string_t *)mb_malloc(i);

		tag->mb_type = MULTIBOOT_TAG_TYPE_BOOT_LOADER_NAME;
		tag->mb_size = i;
		memcpy(tag->mb_string, bootprog_info,
		    strlen(bootprog_info) + 1);
	}

#if !defined(EFI)
	/* Only set in case of BIOS. */
	{
		multiboot_tag_basic_meminfo_t *tag;
		tag = (multiboot_tag_basic_meminfo_t *)
		    mb_malloc(sizeof (*tag));

		tag->mb_type = MULTIBOOT_TAG_TYPE_BASIC_MEMINFO;
		tag->mb_size = sizeof (*tag);
		tag->mb_mem_lower = bios_basemem / 1024;
		tag->mb_mem_upper = bios_extmem / 1024;
	}
#endif

	num = 0;
	for (mfp = fp->f_next; mfp != NULL; mfp = mfp->f_next) {
		num++;
		if (mfp->f_type != NULL && strcmp(mfp->f_type, "rootfs") == 0)
			rootfs++;
	}

	if (num == 0 || rootfs == 0) {
		/* We need at least one module - rootfs. */
		printf("No rootfs module provided, aborting\n");
		error = EINVAL;
		goto error;
	}

	/*
	 * Set the stage for physical memory layout:
	 * - We have kernel at load_addr.
	 * - Modules are aligned to page boundary.
	 * - MBI is aligned to page boundary.
	 * - Set the tmp to point to physical address of the first module.
	 * - tmp != mfp->f_addr only in case of EFI.
	 */
#if defined(EFI)
	tmp = roundup2(load_addr + fp->f_size + 1, MULTIBOOT_MOD_ALIGN);
	module = (multiboot_tag_module_t *)last_addr;
#endif

	for (mfp = fp->f_next; mfp != NULL; mfp = mfp->f_next) {
		multiboot_tag_module_t *tag;

		num = strlen(mfp->f_name) + 1;
		num += strlen(mfp->f_type) + 5 + 1;
		if (mfp->f_args != NULL) {
			num += strlen(mfp->f_args) + 1;
		}
		cmdline = malloc(num);
		if (cmdline == NULL) {
			error = ENOMEM;
			goto error;
		}

		if (mfp->f_args != NULL)
			snprintf(cmdline, num, "%s type=%s %s",
			    mfp->f_name, mfp->f_type, mfp->f_args);
		else
			snprintf(cmdline, num, "%s type=%s",
			    mfp->f_name, mfp->f_type);

		tag = (multiboot_tag_module_t *)mb_malloc(sizeof (*tag) + num);

		tag->mb_type = MULTIBOOT_TAG_TYPE_MODULE;
		tag->mb_size = sizeof (*tag) + num;
#if defined(EFI)
		/*
		 * We can assign module addresses only after BS have been
		 * switched off.
		 */
		tag->mb_mod_start = 0;
		tag->mb_mod_end = mfp->f_size;
#else
		tag->mb_mod_start = mfp->f_addr;
		tag->mb_mod_end = mfp->f_addr + mfp->f_size;
#endif
		memcpy(tag->mb_cmdline, cmdline, num);
		free(cmdline);
		cmdline = NULL;
	}

	md = file_findmetadata(fp, MODINFOMD_SMAP);
	if (md == NULL) {
		printf("no memory smap\n");
		error = EINVAL;
		goto error;
	}

	smap = (struct bios_smap *)md->md_data;
	num = md->md_size / sizeof (struct bios_smap); /* number of entries */

	{
		multiboot_tag_mmap_t *tag;
		multiboot_mmap_entry_t *mmap_entry;

		tag = (multiboot_tag_mmap_t *)
		    mb_malloc(sizeof (*tag) +
		    num * sizeof (multiboot_mmap_entry_t));

		tag->mb_type = MULTIBOOT_TAG_TYPE_MMAP;
		tag->mb_size = sizeof (*tag) +
		    num * sizeof (multiboot_mmap_entry_t);
		tag->mb_entry_size = sizeof (multiboot_mmap_entry_t);
		tag->mb_entry_version = 0;
		mmap_entry = (multiboot_mmap_entry_t *)tag->mb_entries;

		for (i = 0; i < num; i++) {
			mmap_entry[i].mmap_addr = smap[i].base;
			mmap_entry[i].mmap_len = smap[i].length;
			mmap_entry[i].mmap_type = smap[i].type;
			mmap_entry[i].mmap_reserved = 0;
		}
	}

	if (bootp_response != NULL) {
		multiboot_tag_network_t *tag;
		tag = (multiboot_tag_network_t *)
		    mb_malloc(sizeof (*tag) + bootp_response_size);

		tag->mb_type = MULTIBOOT_TAG_TYPE_NETWORK;
		tag->mb_size = sizeof (*tag) + bootp_response_size;
		memcpy(tag->mb_dhcpack, bootp_response, bootp_response_size);
	}

#if !defined(EFI)
	multiboot_tag_vbe_t *tag;
	extern multiboot_tag_vbe_t vbestate;

	if (VBE_VALID_MODE(vbestate.vbe_mode)) {
		tag = (multiboot_tag_vbe_t *)mb_malloc(sizeof (*tag));
		memcpy(tag, &vbestate, sizeof (*tag));
		tag->mb_type = MULTIBOOT_TAG_TYPE_VBE;
		tag->mb_size = sizeof (*tag);
	}
#endif

	if (rsdp != NULL) {
		multiboot_tag_new_acpi_t *ntag;
		multiboot_tag_old_acpi_t *otag;
		uint32_t tsize;

		if (rsdp->Revision == 0) {
			tsize = sizeof (*otag) + sizeof (ACPI_RSDP_COMMON);
			otag = (multiboot_tag_old_acpi_t *)mb_malloc(tsize);
			otag->mb_type = MULTIBOOT_TAG_TYPE_ACPI_OLD;
			otag->mb_size = tsize;
			memcpy(otag->mb_rsdp, rsdp, sizeof (ACPI_RSDP_COMMON));
		} else {
			tsize = sizeof (*ntag) + rsdp->Length;
			ntag = (multiboot_tag_new_acpi_t *)mb_malloc(tsize);
			ntag->mb_type = MULTIBOOT_TAG_TYPE_ACPI_NEW;
			ntag->mb_size = tsize;
			memcpy(ntag->mb_rsdp, rsdp, rsdp->Length);
		}
	}

#if defined(EFI)
#ifdef  __LP64__
	{
		multiboot_tag_efi64_t *tag;
		tag = (multiboot_tag_efi64_t *)
		    mb_malloc(sizeof (*tag));

		tag->mb_type = MULTIBOOT_TAG_TYPE_EFI64;
		tag->mb_size = sizeof (*tag);
		tag->mb_pointer = (uint64_t)(uintptr_t)ST;
	}
#else
	{
		multiboot_tag_efi32_t *tag;
		tag = (multiboot_tag_efi32_t *)
		    mb_malloc(sizeof (*tag));

		tag->mb_type = MULTIBOOT_TAG_TYPE_EFI32;
		tag->mb_size = sizeof (*tag);
		tag->mb_pointer = (uint32_t)ST;
	}
#endif /* __LP64__ */
#endif /* EFI */

	if (have_framebuffer == true) {
		multiboot_tag_framebuffer_t *tag;
		extern multiboot_tag_framebuffer_t gfx_fb;
#if defined(EFI)

		tag = (multiboot_tag_framebuffer_t *)mb_malloc(sizeof (*tag));
		memcpy(tag, &gfx_fb, sizeof (*tag));
		tag->framebuffer_common.mb_type =
		    MULTIBOOT_TAG_TYPE_FRAMEBUFFER;
		tag->framebuffer_common.mb_size = sizeof (*tag);
#else
		extern multiboot_color_t *cmap;
		uint32_t size;

		if (gfx_fb.framebuffer_common.framebuffer_type ==
		    MULTIBOOT_FRAMEBUFFER_TYPE_INDEXED) {
			uint16_t nc;
			nc = gfx_fb.u.fb1.framebuffer_palette_num_colors;
			size = sizeof (struct multiboot_tag_framebuffer_common)
			    + sizeof (nc)
			    + nc * sizeof (multiboot_color_t);
		} else {
			size = sizeof (gfx_fb);
		}

		tag = (multiboot_tag_framebuffer_t *)mb_malloc(size);
		memcpy(tag, &gfx_fb, sizeof (*tag));

		tag->framebuffer_common.mb_type =
		    MULTIBOOT_TAG_TYPE_FRAMEBUFFER;
		tag->framebuffer_common.mb_size = size;

		if (gfx_fb.framebuffer_common.framebuffer_type ==
		    MULTIBOOT_FRAMEBUFFER_TYPE_INDEXED) {
			gfx_fb.u.fb1.framebuffer_palette_num_colors = CMAP_SIZE;

			memcpy(tag->u.fb1.framebuffer_palette, cmap,
			    sizeof (multiboot_color_t) * CMAP_SIZE);
		}
#endif /* EFI */
	}

#if defined(EFI)
	/* Leave EFI memmap last as we will also switch off the BS. */
	{
		multiboot_tag_efi_mmap_t *tag;
		UINTN key;
		EFI_STATUS status;

		tag = (multiboot_tag_efi_mmap_t *)
		    mb_malloc(sizeof (*tag));

		map_size = 0;
		status = BS->GetMemoryMap(&map_size,
		    (EFI_MEMORY_DESCRIPTOR *)tag->mb_efi_mmap, &key,
		    &desc_size, &tag->mb_descr_vers);
		if (status != EFI_BUFFER_TOO_SMALL) {
			error = EINVAL;
			goto error;
		}
		map_size = roundup2(map_size, EFI_PAGE_SIZE);

		i = 2;	/* Attempts to ExitBootServices() */
		while (map_size <= efi_map_size && i > 0) {
			status = BS->GetMemoryMap(&map_size,
			    (EFI_MEMORY_DESCRIPTOR *)tag->mb_efi_mmap, &key,
			    &desc_size, &tag->mb_descr_vers);
			if (status == EFI_BUFFER_TOO_SMALL) {
				/* Still too small? */
				map_size += EFI_PAGE_SIZE;
				continue;
			}
			if (EFI_ERROR(status)) {
				error = EINVAL;
				goto error;
			}

			if (keep_bs != 0)
				break;

			status = BS->ExitBootServices(IH, key);
			if (status == EFI_SUCCESS) {
				has_boot_services = false;
				break;
			}
			i--;
		}
		if (status != EFI_SUCCESS) {
			error = EINVAL;
			goto error;
		}

		tag->mb_type = MULTIBOOT_TAG_TYPE_EFI_MMAP;
		tag->mb_size = sizeof (*tag) + map_size;
		tag->mb_descr_size = (uint32_t)desc_size;

		map = (EFI_MEMORY_DESCRIPTOR *)tag->mb_efi_mmap;

		last_addr += map_size;
		last_addr = roundup2(last_addr, MULTIBOOT_TAG_ALIGN);
	}
#endif /* EFI */

	/*
	 * MB tag list end marker.
	 */
	{
		multiboot_tag_t *tag = (multiboot_tag_t *)
		    mb_malloc(sizeof (*tag));
		tag->mb_type = MULTIBOOT_TAG_TYPE_END;
		tag->mb_size = sizeof (*tag);
	}

	mbi->mbi_total_size = last_addr - (vm_offset_t)mbi;
	mbi->mbi_reserved = 0;

#if defined(EFI)
	/*
	 * At this point we have load_addr pointing to kernel load
	 * address, module list in MBI having physical addresses,
	 * module list in fp having logical addresses and tmp pointing to
	 * physical address for MBI.
	 * Now we must move all pieces to place and start the kernel.
	 */
	head = &relocator->rel_chunk_head;
	STAILQ_INIT(head);

	i = 0;
	chunk = &relocator->rel_chunklist[i++];
	chunk->chunk_vaddr = fp->f_addr;
	chunk->chunk_paddr = load_addr;
	chunk->chunk_size = fp->f_size;

	STAILQ_INSERT_TAIL(head, chunk, chunk_next);

	mp = module;
	for (mfp = fp->f_next; mfp != NULL; mfp = mfp->f_next) {
		chunk = &relocator->rel_chunklist[i++];
		chunk->chunk_vaddr = mfp->f_addr;

		/*
		 * fix the mb_mod_start and mb_mod_end.
		 */
		mp->mb_mod_start = efi_physaddr(module, tmp, map,
		    map_size / desc_size, desc_size, mfp->f_addr,
		    mp->mb_mod_end);
		if (mp->mb_mod_start == 0)
			panic("Could not find memory for module");

		mp->mb_mod_end += mp->mb_mod_start;
		chunk->chunk_paddr = mp->mb_mod_start;
		chunk->chunk_size = mfp->f_size;
		STAILQ_INSERT_TAIL(head, chunk, chunk_next);

		mp = (multiboot_tag_module_t *)
		    roundup2((uintptr_t)mp + mp->mb_size,
		    MULTIBOOT_TAG_ALIGN);
	}
	chunk = &relocator->rel_chunklist[i++];
	chunk->chunk_vaddr = (EFI_VIRTUAL_ADDRESS)(uintptr_t)mbi;
	chunk->chunk_paddr = efi_physaddr(module, tmp, map,
	    map_size / desc_size, desc_size, (uintptr_t)mbi,
	    mbi->mbi_total_size);
	chunk->chunk_size = mbi->mbi_total_size;
	STAILQ_INSERT_TAIL(head, chunk, chunk_next);

	trampoline = (void *)(uintptr_t)relocator + EFI_PAGE_SIZE;
	memmove(trampoline, multiboot_tramp, EFI_PAGE_SIZE);

	relocator->rel_copy = (uintptr_t)trampoline + EFI_PAGE_SIZE;
	memmove((void *)relocator->rel_copy, efi_copy_finish, EFI_PAGE_SIZE);

	relocator->rel_memmove = (uintptr_t)relocator->rel_copy + EFI_PAGE_SIZE;
	memmove((void *)relocator->rel_memmove, memmove, EFI_PAGE_SIZE);
	relocator->rel_stack = relocator->rel_memmove + EFI_PAGE_SIZE - 8;

	trampoline(MULTIBOOT2_BOOTLOADER_MAGIC, relocator, entry_addr);
#else
	dev_cleanup();
	__exec((void *)VTOP(multiboot_tramp), MULTIBOOT2_BOOTLOADER_MAGIC,
	    (void *)entry_addr, (void *)VTOP(mbi));
#endif /* EFI */
	panic("exec returned");

error:
	free(cmdline);

#if defined(EFI)
	free(relocator);

	if (mbi != NULL)
		efi_free_loadaddr((vm_offset_t)mbi, EFI_SIZE_TO_PAGES(size));
#endif

	return (error);
}