config root man

/*-
 * Copyright (c) 1998 Michael Smith <msmith@freebsd.org>
 * Copyright (C) 2006 Semihalf, Piotr Kruszynski <ppk@semihalf.com>
 * Copyright (C) 2007-2008 Semihalf, Rafal Jaworowski <raj@semihalf.com>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD: release/9.1.0/sys/boot/uboot/common/metadata.c 234558 2012-04-21 20:10:26Z raj $");

#include <stand.h>
#include <sys/param.h>
#include <sys/reboot.h>
#include <sys/linker.h>

#include <machine/elf.h>
#include <machine/metadata.h>

#include "api_public.h"
#include "bootstrap.h"
#include "glue.h"

#if defined(LOADER_FDT_SUPPORT)
extern int fdt_fixup(void);
#endif

/*
 * Return a 'boothowto' value corresponding to the kernel arguments in
 * (kargs) and any relevant environment variables.
 */
static struct
{
	const char	*ev;
	int		mask;
} howto_names[] = {
	{"boot_askname",	RB_ASKNAME},
	{"boot_cdrom",		RB_CDROM},
	{"boot_ddb",		RB_KDB},
	{"boot_dfltroot",	RB_DFLTROOT},
	{"boot_gdb",		RB_GDB},
	{"boot_multicons",	RB_MULTIPLE},
	{"boot_mute",		RB_MUTE},
	{"boot_pause",		RB_PAUSE},
	{"boot_serial",		RB_SERIAL},
	{"boot_single",		RB_SINGLE},
	{"boot_verbose",	RB_VERBOSE},
	{NULL,			0}
};

static int
md_getboothowto(char *kargs)
{
	char	*cp;
	int	howto;
	int	active;
	int	i;

	/* Parse kargs */
	howto = 0;
	if (kargs != NULL) {
		cp = kargs;
		active = 0;
		while (*cp != 0) {
			if (!active && (*cp == '-'))
				active = 1;
			else if (active)
				switch (*cp) {
				case 'a':
					howto |= RB_ASKNAME;
					break;
				case 'C':
					howto |= RB_CDROM;
					break;
				case 'd':
					howto |= RB_KDB;
					break;
				case 'D':
					howto |= RB_MULTIPLE;
					break;
				case 'm':
					howto |= RB_MUTE;
					break;
				case 'g':
					howto |= RB_GDB;
					break;
				case 'h':
					howto |= RB_SERIAL;
					break;
				case 'p':
					howto |= RB_PAUSE;
					break;
				case 'r':
					howto |= RB_DFLTROOT;
					break;
				case 's':
					howto |= RB_SINGLE;
					break;
				case 'v':
					howto |= RB_VERBOSE;
					break;
				default:
					active = 0;
					break;
				}
				cp++;
		}
	}

	/* get equivalents from the environment */
	for (i = 0; howto_names[i].ev != NULL; i++) {
		if (getenv(howto_names[i].ev) != NULL)
			howto |= howto_names[i].mask;
	}
	if (!strcmp(getenv("console"), "comconsole"))
		howto |= RB_SERIAL;
	if (!strcmp(getenv("console"), "nullconsole"))
		howto |= RB_MUTE;

	return(howto);
}

/*
 * Copy the environment into the load area starting at (addr).
 * Each variable is formatted as <name>=<value>, with a single nul
 * separating each variable, and a double nul terminating the environment.
 */
static vm_offset_t
md_copyenv(vm_offset_t addr)
{
	struct env_var	*ep;

	/* traverse the environment */
	for (ep = environ; ep != NULL; ep = ep->ev_next) {
		archsw.arch_copyin(ep->ev_name, addr, strlen(ep->ev_name));
		addr += strlen(ep->ev_name);
		archsw.arch_copyin("=", addr, 1);
		addr++;
		if (ep->ev_value != NULL) {
			archsw.arch_copyin(ep->ev_value, addr,
			    strlen(ep->ev_value));
			addr += strlen(ep->ev_value);
		}
		archsw.arch_copyin("", addr, 1);
		addr++;
	}
	archsw.arch_copyin("", addr, 1);
	addr++;
	return(addr);
}

/*
 * Copy module-related data into the load area, where it can be
 * used as a directory for loaded modules.
 *
 * Module data is presented in a self-describing format.  Each datum
 * is preceded by a 32-bit identifier and a 32-bit size field.
 *
 * Currently, the following data are saved:
 *
 * MOD_NAME	(variable)		module name (string)
 * MOD_TYPE	(variable)		module type (string)
 * MOD_ARGS	(variable)		module parameters (string)
 * MOD_ADDR	sizeof(vm_offset_t)	module load address
 * MOD_SIZE	sizeof(size_t)		module size
 * MOD_METADATA	(variable)		type-specific metadata
 */
#define	COPY32(v, a, c) {			\
    u_int32_t	x = (v);			\
    if (c)					\
	archsw.arch_copyin(&x, a, sizeof(x));	\
    a += sizeof(x);				\
}

#define	MOD_STR(t, a, s, c) {			\
    COPY32(t, a, c);				\
    COPY32(strlen(s) + 1, a, c)			\
    if (c)					\
	archsw.arch_copyin(s, a, strlen(s) + 1);\
    a += roundup(strlen(s) + 1, sizeof(u_long));\
}

#define	MOD_NAME(a, s, c)	MOD_STR(MODINFO_NAME, a, s, c)
#define	MOD_TYPE(a, s, c)	MOD_STR(MODINFO_TYPE, a, s, c)
#define	MOD_ARGS(a, s, c)	MOD_STR(MODINFO_ARGS, a, s, c)

#define	MOD_VAR(t, a, s, c) {			\
    COPY32(t, a, c);				\
    COPY32(sizeof(s), a, c);			\
    if (c)					\
	archsw.arch_copyin(&s, a, sizeof(s));	\
    a += roundup(sizeof(s), sizeof(u_long));	\
}

#define	MOD_ADDR(a, s, c)	MOD_VAR(MODINFO_ADDR, a, s, c)
#define	MOD_SIZE(a, s, c)	MOD_VAR(MODINFO_SIZE, a, s, c)

#define	MOD_METADATA(a, mm, c) {		\
    COPY32(MODINFO_METADATA | mm->md_type, a, c);\
    COPY32(mm->md_size, a, c);			\
    if (c)					\
	archsw.arch_copyin(mm->md_data, a, mm->md_size);\
    a += roundup(mm->md_size, sizeof(u_long));	\
}

#define	MOD_END(a, c) {				\
    COPY32(MODINFO_END, a, c);			\
    COPY32(0, a, c);				\
}

static vm_offset_t
md_copymodules(vm_offset_t addr)
{
	struct preloaded_file	*fp;
	struct file_metadata	*md;
	int			c;
	vm_offset_t a;

	c = addr != 0;
	/* start with the first module on the list, should be the kernel */
	for (fp = file_findfile(NULL, NULL); fp != NULL; fp = fp->f_next) {

		MOD_NAME(addr, fp->f_name, c);	/* this field must be first */
		MOD_TYPE(addr, fp->f_type, c);
		if (fp->f_args)
			MOD_ARGS(addr, fp->f_args, c);
		a = fp->f_addr - __elfN(relocation_offset);
		MOD_ADDR(addr, a, c);
		MOD_SIZE(addr, fp->f_size, c);
		for (md = fp->f_metadata; md != NULL; md = md->md_next) {
			if (!(md->md_type & MODINFOMD_NOCOPY))
				MOD_METADATA(addr, md, c);
		}
	}
	MOD_END(addr, c);
	return(addr);
}

/*
 * Load the information expected by a kernel.
 *
 * - The 'boothowto' argument is constructed
 * - The 'bootdev' argument is constructed
 * - The kernel environment is copied into kernel space.
 * - Module metadata are formatted and placed in kernel space.
 */
int
md_load(char *args, vm_offset_t *modulep)
{
	struct preloaded_file	*kfp, *bfp;
	struct preloaded_file	*xp;
	struct file_metadata	*md;
	struct bootinfo		*bip;
	vm_offset_t		kernend;
	vm_offset_t		addr;
	vm_offset_t		envp;
	vm_offset_t		size;
	vm_offset_t		vaddr;
	vm_offset_t		dtbp;
	char			*rootdevname;
	int			howto;
	int			i;

	/*
	 * These metadata addreses must be converted for kernel after
	 * relocation.
	 */
	uint32_t		mdt[] = {
	    MODINFOMD_SSYM, MODINFOMD_ESYM, MODINFOMD_KERNEND,
	    MODINFOMD_ENVP,
#if defined(LOADER_FDT_SUPPORT)
	    MODINFOMD_DTBP
#endif
	};

	howto = md_getboothowto(args);

	/*
	 * Allow the environment variable 'rootdev' to override the supplied
	 * device. This should perhaps go to MI code and/or have $rootdev
	 * tested/set by MI code before launching the kernel.
	 */
	rootdevname = getenv("rootdev");
	if (rootdevname == NULL)
		rootdevname = getenv("currdev");
	/* Try reading the /etc/fstab file to select the root device */
	getrootmount(rootdevname);

	/* Find the last module in the chain */
	addr = 0;
	for (xp = file_findfile(NULL, NULL); xp != NULL; xp = xp->f_next) {
		if (addr < (xp->f_addr + xp->f_size))
			addr = xp->f_addr + xp->f_size;
	}
	/* Pad to a page boundary */
	addr = roundup(addr, PAGE_SIZE);

	/* Copy our environment */
	envp = addr;
	addr = md_copyenv(addr);

	/* Pad to a page boundary */
	addr = roundup(addr, PAGE_SIZE);

	kernend = 0;
	kfp = file_findfile(NULL, "elf32 kernel");
	if (kfp == NULL)
		kfp = file_findfile(NULL, "elf kernel");
	if (kfp == NULL)
		panic("can't find kernel file");
	file_addmetadata(kfp, MODINFOMD_HOWTO, sizeof howto, &howto);
	file_addmetadata(kfp, MODINFOMD_ENVP, sizeof envp, &envp);

#if defined(LOADER_FDT_SUPPORT)
	/* Handle device tree blob */
	dtbp = fdt_fixup();
	if (dtbp != (vm_offset_t)NULL)
		file_addmetadata(kfp, MODINFOMD_DTBP, sizeof dtbp, &dtbp);
	else
		pager_output("WARNING! Trying to fire up the kernel, but no "
		    "device tree blob found!\n");
#endif

	file_addmetadata(kfp, MODINFOMD_KERNEND, sizeof kernend, &kernend);

	/* Figure out the size and location of the metadata */
	*modulep = addr;
	size = md_copymodules(0);
	kernend = roundup(addr + size, PAGE_SIZE);

	/* Provide MODINFOMD_KERNEND */
	md = file_findmetadata(kfp, MODINFOMD_KERNEND);
	bcopy(&kernend, md->md_data, sizeof kernend);

	/* Convert addresses to the final VA */
	*modulep -= __elfN(relocation_offset);

	for (i = 0; i < sizeof mdt / sizeof mdt[0]; i++) {
		md = file_findmetadata(kfp, mdt[i]);
		if (md) {
			bcopy(md->md_data, &vaddr, sizeof vaddr);
			vaddr -= __elfN(relocation_offset);
			bcopy(&vaddr, md->md_data, sizeof vaddr);
		}
	}

	/* Only now copy actual modules and metadata */
	(void)md_copymodules(addr);

	return (0);
}