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This patch is to introduce multiboot 2 loading capabilities to grub2

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for powerpc & i386-pc. This patch was more so started by Hollis
Blanchard getting multiboot 2 working for powerpc and I added to it
and cleaned it up.

One of the ideas with this patch is to keep everything under one
command for the user. So instead of having a "multiboot2" & "module2"
command, I created a proxy like mechanism so that you have only one
command for both multiboot 1 & 2 ... "multiboot". This is where
"loader/multiboot_loader.c" comes from. I could have integrated things
more but I figure the current approach will less likely break
anything.

So if your OS is multiboot 2 capable, the user would do the following
to load it up from a grub prompt:

grub> multiboot <location of kernel> <kernel args>
grub> module <some image> <multiboot tag> <image arguments>
grub> module <isome mage> <multiboot tag> <image arguments>
grub .....


The other thing that this patch does is it begins to make the
multiboot 1 code a bit more architecture agnostic so IF someone wanted
to implement it on another architecture they can.

A bit of file moving around and definition renaming is also apart of
this patch. I have also taken the time to make sure that it does not
break multiboot 1 loading on i386-pc. But mulitboot 2 may still need a
little more testing and work for i386-pc. Powerpc multiboot 2 has been
heavily tested and does work.
This commit is contained in:
jerone 2007-07-25 00:44:03 +00:00
parent daf0f0ba3e
commit e5dfe7775a
17 changed files with 1315 additions and 300 deletions
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176
loader/multiboot_loader.c Normal file
View file

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/* multiboot_loader.c - boot multiboot 1 or 2 OS image */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2007 Free Software Foundation, Inc.
*
* GRUB 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 3 of the License, or
* (at your option) any later version.
*
* GRUB 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 GRUB. If not, see <http://www.gnu.org/licenses/>.
*/
#include <multiboot2.h>
#include <grub/multiboot_loader.h>
#include <grub/multiboot.h>
#include <grub/multiboot2.h>
#include <grub/elf.h>
#include <grub/file.h>
#include <grub/err.h>
#include <grub/rescue.h>
#include <grub/dl.h>
#include <grub/mm.h>
#include <grub/misc.h>
#include <grub/gzio.h>
grub_dl_t my_mod;
/* This tracks which version of multiboot to use when using
* the module command. By default use multiboot version 1.
* values:
* 1 - Mulitboot version 1
* 2 - Mutliboot version 2
*/
static unsigned int module_version_status = 1;
static int
find_multi_boot1_header (grub_file_t file)
{
struct grub_multiboot_header *header;
char buffer[MULTIBOOT_SEARCH];
int found_status = 0;
grub_ssize_t len;
len = grub_file_read (file, buffer, MULTIBOOT_SEARCH);
if (len < 32)
return found_status;
/* Look for the multiboot header in the buffer. The header should
be at least 12 bytes and aligned on a 4-byte boundary. */
for (header = (struct grub_multiboot_header *) buffer;
((char *) header <= buffer + len - 12) || (header = 0);
header = (struct grub_multiboot_header *) ((char *) header + 4))
{
if (header->magic == MULTIBOOT_MAGIC
&& !(header->magic + header->flags + header->checksum))
{
found_status = 1;
break;
}
}
return found_status;
}
void
grub_rescue_cmd_multiboot_loader (int argc, char *argv[])
{
grub_file_t file = 0;
int header_multi_ver_found = 0;
grub_dl_ref (my_mod);
if (argc == 0)
{
grub_error (GRUB_ERR_BAD_ARGUMENT, "No kernel specified");
goto fail;
}
file = grub_gzfile_open (argv[0], 1);
if (! file)
{
grub_error (GRUB_ERR_BAD_ARGUMENT, "Couldn't open file");
goto fail;
}
/* find which header is in the file */
if (find_multi_boot1_header(file))
header_multi_ver_found = 1;
else
{
/* The behavior is that if you don't find a multiboot 1 header
use multiboot 2 loader (as you do not have to have a header
to use multiboot 2 */
grub_dprintf ("multiboot_loader", "No multiboot 1 header found. \n \
Using multiboot 2 loader\n");
header_multi_ver_found = 0;
}
/* close file before calling functions */
if (file)
grub_file_close (file);
/* Launch multi boot with header */
/* XXX Find a better way to identify this.
This is for i386-pc */
#ifdef __i386__
if (header_multi_ver_found == 1)
{
grub_dprintf ("multiboot_loader",
"Launching multiboot 1 grub_multiboot() function\n");
grub_multiboot (argc, argv);
module_version_status = 1;
}
#endif
if (header_multi_ver_found == 0 || header_multi_ver_found == 2)
{
grub_dprintf ("multiboot_loader",
"Launching mulitboot 2 grub_multiboot2() function\n");
grub_multiboot2 (argc, argv);
module_version_status = 2;
}
return;
fail:
if (file)
grub_file_close (file);
grub_dl_unref (my_mod);
}
void
grub_rescue_cmd_module_loader (int argc, char *argv[])
{
#ifdef __i386__
if (module_version_status == 1)
{
grub_dprintf("multiboot_loader",
"Launching multiboot 1 grub_module() function\n");
grub_module (argc, argv);
}
#endif
if (module_version_status == 2)
{
grub_dprintf("multiboot_loader",
"Launching multiboot 2 grub_module2() function\n");
grub_module2 (argc, argv);
}
}
GRUB_MOD_INIT(multiboot)
{
grub_rescue_register_command ("multiboot", grub_rescue_cmd_multiboot_loader,
"load a multiboot kernel");
grub_rescue_register_command ("module", grub_rescue_cmd_module_loader,
"load a multiboot module");
my_mod = mod;
}
GRUB_MOD_FINI(multiboot)
{
grub_rescue_unregister_command ("mulitboot");
grub_rescue_unregister_command ("module");
}