elilo.c

EFI（Extensible Firmware Interface)是下一代BIOS

/* 
 * elilo.c - IA-64/IA-32 EFI Linux loader
 *
 *  Copyright (C) 1999-2003 Hewlett-Packard Co.
 *	Contributed by David Mosberger <[e-mail]>.
 *	Contributed by Stephane Eranian <[e-mail]>
 *
 *  Copyright (C) 1999-2000 VA Linux Systems
 *       Contributed by Johannes Erdfelt <[e-mail]>.
 *
 * This file is part of the ELILO, the EFI Linux boot loader.
 *
 *  ELILO 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, or (at your option)
 *  any later version.
 *
 *  ELILO 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 ELILO; see the file COPYING.  If not, write to the Free
 *  Software Foundation, 59 Temple Place - Suite 330, Boston, MA
 *  02111-1307, USA.
 *
 * Please check out the elilo.txt for complete documentation on how
 * to use this program.
 */

#include <efi.h>
#include <efilib.h>

#include "elilo.h"
#include "vars.h"

#include "getopt.h"
#include "fileops.h"
#include "loader.h"
#include "config.h" /* for config_init() */

#define ELILO_VERSION			L"3.4"
#define ELILO_SHARED_CMDLINE_OPTS	L"pPMC:aDhd:i:vVc:E"

elilo_config_t elilo_opt;

EFI_SYSTEM_TABLE *systab;	/* pointer to EFI system table */

/*
 * Load the Linux kernel in memory from the boot media
 * Output:
 * 	kd = address of kernel entry point
 * 	   + end address of kernel code+data+bss
 * 	   + kernel entry point
 * Return:
 * 	ELILO_LOAD_ERROR   : if something went wrong
 * 	ELILO_LOAD_ABORTED : user interruption while loading
 * 	ELILO_LOAD_SUCCESS : otherwise
 */
static INTN
do_kernel_load(CHAR16 *kname, kdesc_t *kd)
{
	loader_ops_t	*ldops;
	EFI_STATUS status;
	fops_fd_t fd;

	status = fops_open(kname, &fd);
	if (EFI_ERROR(status)) {
		ERR_PRT((L"Kernel file  not found %s", kname));
		return ELILO_LOAD_ERROR;
	}
	fops_close(fd);

	ldops = loader_probe(kname);
	if (ldops == NULL) {
		ERR_PRT((L"Cannot find a loader for %s", kname));
		return ELILO_LOAD_ERROR;
	}

	VERB_PRT(1,Print(L"Using %s loader\n", ldops->ld_name));
	
	return ldops->ld_load_kernel(kname, kd);
}

INTN
kernel_load(EFI_HANDLE image, CHAR16 *kname, kdesc_t *kd, memdesc_t *imem)
{

	/*
	 * Now let's try to load the kernel !
	 */
	switch(do_kernel_load(kname, kd)) {
		case ELILO_LOAD_SUCCESS:
			break;

		case ELILO_LOAD_ERROR:
			/* XXX: add fallback support */
			return ELILO_LOAD_ERROR;
		
		case ELILO_LOAD_ABORTED:
			/* we drop initrd in case we aborted the load */
			elilo_opt.initrd[0] = CHAR_NULL;

			/* will go back to interactive selection */
			elilo_opt.prompt  = 1; 
			elilo_opt.timeout = ELILO_DEFAULT_TIMEOUT;
			elilo_opt.delay   = 0;

			return ELILO_LOAD_RETRY;	
	}

	VERB_PRT(3, Print(L"kernel loaded in [0x%lx-0x%lx] entry=0x%lx\n", 
			  (UINT64)kd->kstart, (UINT64)kd->kend, (UINT64)kd->kentry));

	if (elilo_opt.initrd[0]) {

		if (sysdeps_initrd_get_addr(kd, imem) == -1) goto exit_error;

		switch(load_initrd(elilo_opt.initrd, imem)) {
			case ELILO_LOAD_SUCCESS:
				break;
			case ELILO_LOAD_ERROR:
				goto exit_error;
			case ELILO_LOAD_ABORTED:
				/* the free_kmem() is the responsibility of the loader */

				/* we drop initrd in case we aborted the load */
				elilo_opt.initrd[0] = CHAR_NULL;
				elilo_opt.prompt    = 1; 
				elilo_opt.timeout   = ELILO_DEFAULT_TIMEOUT;
				elilo_opt.delay     = 0;

				return ELILO_LOAD_RETRY;
		}
	}
	return ELILO_LOAD_SUCCESS;
exit_error:
	free_kmem();
	if (imem->start_addr) free(imem->start_addr);

	return ELILO_LOAD_ERROR;
}

static INTN
main_loop(EFI_HANDLE dev, CHAR16 **argv, INTN argc, INTN index, EFI_HANDLE image)
{
	CHAR16 kname[FILENAME_MAXLEN];
	CHAR16 cmdline_tmp[CMDLINE_MAXLEN];
	CHAR16 cmdline[CMDLINE_MAXLEN];
	VOID *bp;
	UINTN cookie;
	EFI_STATUS status = EFI_SUCCESS;
	kdesc_t kd;
	memdesc_t imem;
	INTN r;

	/*
	 * First place where we potentially do system dependent
	 * operations. It is a one time opportunity before entering
	 * the main loop
	 */
	if (sysdeps_preloop_actions(dev, argv, argc, index, image) == -1) return -1;

	for(;;) {
		kname[0] = cmdline_tmp[0] = cmdline[0] = CHAR_NULL;
		imem.start_addr = 0; imem.pgcnt = 0;
		elilo_opt.sys_img_opts = NULL;

		if (kernel_chooser(argv, argc, index, kname, cmdline_tmp) == -1) goto exit_error;

		switch (kernel_load(image, kname, &kd, &imem)) {
			case ELILO_LOAD_SUCCESS: 
				goto do_launch;
			case ELILO_LOAD_ERROR:
				goto exit_error;
			/* otherwise we retry ! */
		}
	} 

do_launch:
	r =subst_vars(cmdline_tmp, cmdline, CMDLINE_MAXLEN);

	VERB_PRT(3, Print(L"final cmdline(%d): %s\n", r, cmdline));

	/* free resources associated with file accesses (before ExitBootServices) */
	close_devices();

	/* No console output permitted after create_boot_params()! */
	if ((bp=create_boot_params(cmdline, &imem, &cookie)) == 0) goto error;

	/* terminate bootservices */
	status = BS->ExitBootServices(image, cookie);
	if (EFI_ERROR(status)) goto bad_exit;

	start_kernel(kd.kentry, bp);
	/* NOT REACHED */

	ERR_PRT((L"start_kernel() return !"));
bad_exit:	
	/*
	 * we are still in BootService mode
	 */
	ERR_PRT((L"ExitBootServices failed %r", status));
error:
	free_kmem();
	if (imem.start_addr) free(imem.start_addr);
	if (bp) free_boot_params(bp);
exit_error:
	return ELILO_LOAD_ERROR;

}

static VOID
elilo_help(VOID)
{
	
	Print(L"-d secs   timeout in 10th of second before booting\n");
	Print(L"-h        this help text\n");
	Print(L"-V        print version\n");
	Print(L"-v        verbose level(can appear multiple times)\n");
	Print(L"-a        always check for alternate kernel image\n");
	Print(L"-i file   load file as the initial ramdisk\n");
	Print(L"-C file   indicate the config file to use\n");
	Print(L"-P        parse config file only (verify syntax)\n");
	Print(L"-D        enable debug prints\n");
	Print(L"-p        force interactive mode\n");
	Print(L"-c name   image chooser to use\n");
	Print(L"-E        do not force EDD30 variable\n");

	sysdeps_print_cmdline_opts();

	Print(L"\n");

	print_config_options();
}

/*
 * XXX: hack to work around a problem with EFI command line argument when booted
 * from network. In this case, it looks like LoadOptions/LoadOptionsSize contain
 * garbage
 */
static CHAR16 *default_load_options;
static UINTN default_load_options_size;
static INTN done_fixups;

static VOID
fixupargs(EFI_LOADED_IMAGE *info)
{
	EFI_STATUS status;
	EFI_PXE_BASE_CODE *pxe;

#define FAKE_ELILONAME	L"elilo-forced"

	status = BS->HandleProtocol (info->DeviceHandle, &PxeBaseCodeProtocol, (VOID **)&pxe);
	if (EFI_ERROR(status)) return;

	default_load_options      = info->LoadOptions;
	default_load_options_size = info->LoadOptionsSize;

	info->LoadOptions     = FAKE_ELILONAME;
	info->LoadOptionsSize = StrLen(info->LoadOptions)*sizeof(CHAR16);

	done_fixups = 1;
}

/*
 * we restore the arguments in case we modified them just to make sure
 * we don't confuse caller.
 */
static VOID
unfixupargs(EFI_LOADED_IMAGE *info)
{
	if (done_fixups == 0) return;

	info->LoadOptions     = default_load_options;
	info->LoadOptionsSize = default_load_options_size;
}


/*
 * in order to get fully detailed EFI path names to devices, EDD3.0 specification must
 * be turned on. On new versions of EFI, this is the default. An environment variable
 * called EDD30 reflects the current settings. If true, then EDD3.0 is enabled 
 * and device path names show the detailed device types. If false, then a default 
 * generic name is used instead. This has some implications of ELILO's ability to 
 * provide a better naming scheme for detected devices. If EDD3.0 is enabled
 * then much more precise names can be used which makes it easy to use. 
 * If EDD3.0 is nont enabled, ELILO will still work but will use very generic names
 * for devices.
 *
 * ELILO will check the value of the variable. If not true, then it will force it to
 * true. This will require a reboot for EFI to make use of the new value.
 * Return:
 * 	EFI_SUCCESS: if variable is already true or was set to true
 * 	EFI error code: otherwise, like when could not forced variable or unrecognized variable content
 */
#define EDD30_GUID \
{0x964e5b21, 0x6459, 0x11d2, { 0x8e, 0x39, 0x00, 0xa0, 0xc9, 0x69, 0x72, 0x3b}}

#define EDD30_ATTR (EFI_VARIABLE_RUNTIME_ACCESS|EFI_VARIABLE_BOOTSERVICE_ACCESS|EFI_VARIABLE_NON_VOLATILE)

static EFI_GUID edd30_guid = EDD30_GUID;

static INTN
check_edd30(VOID)
{
	EFI_STATUS	status;
	UINTN		l = sizeof(BOOLEAN);
	UINT8		bool = FALSE;
	INTN		ret = -1;

	status = RT->GetVariable(L"EDD30", &edd30_guid, NULL, &l, &bool);
	if (status == EFI_BUFFER_TOO_SMALL || (bool != TRUE && bool != FALSE)) {
		ERR_PRT((L"Warning: EDD30 EFI variable is not boolean value: forcing it to TRUE"));
		return -1;
	}
	if (status == EFI_SUCCESS && bool == TRUE) {
		VERB_PRT(3, Print(L"EDD30 is TRUE\n"));
		elilo_opt.edd30_on = TRUE;
		ret = 0;
	} else {
		VERB_PRT(4, 
			if (status != EFI_SUCCESS) {
				Print(L"EDD30 EFI variable not defined\n");
			} else {
				Print(L"EDD30 EFI variable is false\n");
			}
		);
	}

	return ret;
}

static INTN