It boots FreeBSD from a running MS-DOS system.
It's compiled using some MS-DOS tools, but there is a binary
hidden in the uuencoded file. (Go ahead, flame me if you can come up
with a solution for the problem. Just saying "this is bad" doesn't count!)
Rod, you were right: one would have to deal with weird interfaces to the
memory managers, and it seems that Christian found them all, and made them
work.
Thanks Christian!
Reviewed by: phk
Submitted by: DI. Christian Gusenbauer <cg@fimp01.fim.uni-linz.ac.at>
Christians README:
------------------
Hi Everybody!
This is version 1.5 of "fbsdboot", a program that allows you to boot a kernel
from a MS-DOS partition or a FreeBSD partition. This program runs using DOS.
It works with various memory managers (like EMM386, 386MAX) under certain
circumstances.
First, a FreeBSD kernel is always loaded to memory starting at 0x100000. To
assure that loading the kernel *does not* overwrite memory used by memory
managers, high memory for the kernel is allocated and after loading the kernel
it's moved to 0x100000.
Second, there are many ways to switch to protected mode which is necessary to
start the kernel. Each BIOS gives you the possibility to use INT15H (AH=89H)
to do that. But some memory-managers like 386max does not allow you to use
this method.
An other way to do the switch is to use DPMI services, but they do not
guarantee, that the protected mode application is executed with privilege
level 0. Therefore this method is *not* used.
VCPI services offer another way to switch to protected mode, and VCPI servers
are built into "emm386.exe", "386max" and "qemm". That's why, this method is
implemented in fbsdboot.exe.
Fbsdboot.exe tries to switch to protected mode using VCPI services. If they're
not available INT15H is used to do the switch. If that fails, it's not possible
for this version of fbsdboot.exe to boot a kernel :-(.
You can get commandline options of fbsdboot if you start it with "-?" as option!
I don't know, if fbsdboot works with QEMM, as I don't have the possibility to
test it.
Enjoy and have fun!
Christian.
cg@fimp01.fim.uni-linz.ac.at
PS: Many thanks to Bruce Evans for his assistance!
Submitted by: Rich
Make conditionals on BIOSWAIT consistent with usage in io.c.
If you had 'BOOTWAIT=0' in your /etc/make.conf then biosboot wouldn't
compile. It was '#if' in io.c and '#ifdef' in probe_keyboard.c so I
changed the latter to '#if'.
Even if BOOTWAIT is undefined then '#if BOOTWAIT' becomes
'#if 0' so it should compile either way with this change.
(Boot with the -D flag if you want symbols.)
Make it easier to extend `struct bootinfo' without losing either forwards
or backwards compatibility.
ddb_aout.c:
Get the symbol table from wherever the loader put it.
Nuke db_symtab[SYMTAB_SPACE].
boot.c:
Enable loading of symbols. Align them on a page boundary. Add printfs
about the symbol table sizes.
Pass the memory sizes to the kernel.
Fix initialization of `unit' (it got moved out of the loop).
Fix adding the bss size (it got moved inside an ifdef).
Initialize serial port when RB_SERIAL is toggled on.
Fix comments.
Clean up formatting of recently added code.
io.c:
Clean up formatting of recently added code.
netboot/main.c, machdep.c, wd.c:
Change names of bootinfo fields.
LINT:
Nuke SYMTAB_SPACE.
Fix comment about DODUMP.
Makefile.i386:
Nuke use of dbsym.
Exclude gcc symbols from kernel unless compiling with -g.
Remove unused macro.
Fix comments and formatting.
genassym.c:
Generate defines for some new bootinfo fields. Change names of old ones.
locore.s:
Copy only the valid part of the `struct bootinfo' passed by the loader.
Reserve space for symbol table, if any.
machdep.c:
Check the memory sizes passed by the loader, if any. Don't use them yet.
bootinfo.h:
Add a size field so that we can resolve some mismatches between the loader
bootinfo and the kernel boot info. The version number is not so good for
this because of historical botches and because it's harder to maintain.
Add memory size and symbol table fields. Change the names of everything.
Hacks to save a few bytes:
asm.S, boot.c, boot2.S:
Replace `ouraddr' by `(BOOTSEG << 4)'.
boot.c:
Don't statically initialize `loadflags' to 0. Disable the "REDUNDANT"
code that skips the BIOS variables. Eliminate `total'. Combine some
more printfs.
boot.h, disk.c, io.c, table.c:
Move all statically initialzed data to table.c.
io.c:
Don't put the A20 gate bits in a variable.
Obtained from:
bios boot block changed to allow booting from both the attached graphics
display and from a serial port. (A specially compiled serial boot block
is no longer necessary.) The boot block should detect the presence or
absence of a keyboard: if there is no keyboard, COM1 is turned into the
console. This simulates the behavior of the Sun boot PROMs. Unplug your
keyboard, attach a terminal to COM1 and you should be ready to go. :)
boot(). This is needed so the "serialboot" stuff can share this file,
too.
Everything is #ifdef'ed so it evaluates to nothing when actually been
built in the "biosboot" directory.
The files in this directory are modified version of "biosboot". The
only difference is in that they perform their I/O via a serial port,
so their preferrable usage is to form bootblocks for systems where the
kernel happens to have an "options COMCONSOLE". Most of the code is
actually shared with "biosboot", and make will not (and should not)
descend into this directory by default. It is in the responsibility
of the user to build these bootblocks instead of the original ones.
Subject: Mea culpa -- small fix for netboot fixes
In accordance with the unavoidable principle sof Murphy's Law, I discovered
that the fixes I recently contributed for the netboot code had some small
flaws in them. Two of them were just typos and had no effect on how the
program functioned. The other one was a missing line from the rootopts and
swapopts functions I created in bootmenu.c, which was supposed to initialize
the NFS sotype flag. It defaults to UDP, and you can change it to TCP with
the rootopts or swapopts commands, but then you can't change it back again.
I originally had a line at the top of each function to reinitialize this
flag, but somehow it got lost in the shuffle, probably because I don't
actually have a need for that flag yet.
Submitted by: wpaul
Smack the netboot program around so that it will allow the user to
specify mount options. [So that you can boot from a privileged port]
Change the default boot image name in netboot to /kernel, then strip
the leading slash when actually going out to get the NFS file handle.
Added support for 3Com 3c503 cards. Also added another command to
the (trans) that allows you to switch the 3Com's on-board transceiver
on and off. (ether.c, ether.h, bootmenu.c)
Modified the Makefile to support new compile-time options for 3c503
cards:
-DINCLUDE_3COM Include support for 3c503
-D_3COM_BASE=0x300 Define 3c503 base i/o address (if not
specified, 0x300 is the default)
-D_3COM_USE_AUI Disable the 3c503's transceiver by
default (without this flag the transceiver
is on by default)
I have put it here, because I belive we could share some code among the
various kinds of boot-code, whenever we get the time to look at it.
Submitted by: Martin Renters
been relocated to run in the 64k segment at 0x10000 with the stack at
the top of this segment. This corrects the problems machines with 512K
base memory had booting.
2. startprog routing rewritten to convert the BOOTSEG ss to a KERNELSEG
ss, this eliminated the last of the >512K memory references. Additional
cleanup in here included a better way to copy the arguments to the
kernel stack.
3. Elimination of argv and esym cruft saved a few bytes.
4. Only need to truncate the head.a_entry to a meg boundary once intead
of every time we used it! [Saving more bytes].
5. Addition of version 1 bootinfo structure support. These boot blocks
pass the kernel name in to the kernel now.
6. Removed historical comments about MACH argv stuff, as it is useless now.
2. Clean up the .S files to use /* */ style comments.
This is a totally cosmetic change, not one byte of the resulting boot
code changes. But at least it is installed with correct owners and in
the right places, and gets recompiled correctly when things change!
is used instead of /usr/lib
io.c: add #include <machine/cpufunc.h> as instructed by David Greenman to
avoid inb/outb linking errors.
NOTE: I just discovered that if GNUC is not used the inline functions will not be expanded from the include file and real inb/outb functions would
be needed.
