Saved a few bytes by copying `dosdev' and/or `name' to local variables.
This optimization (for dosdev) was done in one place before but this
was lost in the devread() cleanup. This optimization (for dosdev)
can almost be done by bogusly declaring dosdev as const, but gcc still
often space-pessimizes code like the following:
extern const int dosdev; ... foo(dosdev); bar(dosdev);
gcc often doesn't bother to copy dosdev to a temporary local because
the local would have to be preserved in memory across the call to
foo(). OTOH, for
extern int dosdev; ... auto int dosdev_copy = dosdev; ...
foo(dosdev_copy); bar(dosdev_copy);
the copy must be made because foo() might alter dosdev.
the pointer to the string "/kernel". This pointer was once only
statically to once save space, but it has had to be dynamically
initialized for some time, so the static initialization just wastes
space. The string gets moved to the text section, so the actual
savings may be negative due to padding.
- avoiding strcmp("?" saved 12 bytes. gcc inlined the strcmp()
but this takes as much or more code as a function call. The
inlining was bogus because the strcmp() in the bootstrap isn't
standard.
- using a char instead of an int for the boolean `last_only' saved 8
bytes. Booleans should usually be represented as chars on the i386.
- simplifying the return tests saved 9 bytes.
- using putc instead of printf to print a newline saved 3 bytes of code
and 2 bytes of const data.
- avoiding `else's by always doing the else clause and fixing it up
saved 4+8 bytes.
gcc always generates large code for accesses to globals. For locals
it only generates large code if there are more than 128 bytes of
locals. It sorts scalar locals after array locals to pessimize for
space in the usual case when there are more (static) references to
scalars than to arrays.
Saved another 16 bytes (13 before padding) by adding a `continue'.
Fall-through tests normally save space, but here one of them made
gcc do space-unoptimal register allocation (it allocates ch in %bl
because preserving this register across function calls is "free",
but comparisions with %bl take one byte fewer than comparsions with
%bl).
I just couldn't get the code to be as small as it should have gotten..
atill a LITTLE bigger than before as I need to allow the
default string to have options as well
1/ Makefile: the maximum size for boot2 is 7.5K not 7K,
so don't complain until it reaches THAT size..
newfs leaves 8K and boot 1 is 512k. leaving 7.5K becasue the disklabel
is considered to part of the boot2 file.
[512 boot1][512 disklabel][ 7K boot2 code ]
[boot1 file][ boot2 file ]
2/ Boot2.S: move the soring of the default name read from block 2 to AFTER
clearing the BSS.
3/ boot.c:
Move the parsing of the command line into the
place it's called for clarity.. alsoi comment it a bit and clean it
up a bit.. for some reason this seems ot have made it a little
larger, but I can't work out why.. maybe bruce might have ideas?
compensated for by shrinkage elsewhere..
the practical result of this is htat the default string can now contain args
e.g. if you change the default string to have -gd
then the machine will boot to the dgb debugger stub by default..
this is mostly useful with the nextboot utility..
as it now allows you to remotely force a machine to reboot into
the debugger.
is only appropriate to use in the special environment of start.S (real
mode plus some conventions about not saving registers), and asm.h is
supposed to be for generic macros.
Removed some unnecessary parentheses.
Add code to the boot blocks to allow the user to place default boot strings
on block 1 of the disk (2nd block), should the correct magic numbers be present.
If the correct options are used it will 'delete' the name used from block1,
thereby assuring that if the boot fails it won't be stuck in an infinite loop.
the boot strings are set by the utility "nextboot"
(not yet checked in, but being tested.)
By default these changes should have no effect on existing installations
and if compiled without the NAMEBLOCK option should be essentially identical
to the old ones.
hd essentially wired the FreeBSD drive number to 0 without changing
the BIOS drive number. Now the numbers can be specified independently.
Replaced the BOOT_HD compile time flag with with BOOT_HD_BIAS. Defining
the new flag as 1 should give the same behaviour as defining the old
flag as anything. I haven't tested defining these flags.
is defined and FORCE_COMCONSOLE isn't defined.
Don't compile any keyboard probing code if PROBE_KEYBOARD isn't defined.
Makefile:
Removed -I paths. They weren't used, and the one to /sys hasn't worked
since the source directory was moved down one level.
counter instead of the BIOS time call to save space.
Reworked the anti-noise timeout to avoid duplicating code. The timeout
in the outer loop is now restarted after every noise timeout, so it is
now possible for the total timeout to be infinite; previously, the maximum
total timeout was 150000 seconds.
must have limit 0xffff and attribute G = 0 (byte granularity) as well
as other properties that they already had (see e.g., the Intel i486
manual section 22.5). Not restoring them broke Ctrl-Alt-Del in the
bootstrap for my ASUS P55TP4XE system, probably because the Award BIOS
does anti-tracing stuff involving inaccessible %esp's.
asm.S:
Don't use lret in prot_to_real(). This reduces the risk of using an
incompletely intialized stack segment and saves space.
Submitted by: "K.Higashino" <a00303@cc.hc.keio.ac.jp> (on 13 Jan 1995!)
reworked by me
boot to display "Booting the kernelel...done" instead of "Booting
the kernel".
Removed save and restore of BIOS memory. kzipped kernels haven't
ever overlaid the BIOS memory.
ignore and set it to 18 sectors/track. This allows FreeBSD to boot with
2.88MB floppies which are used in older ThinkPads.
Submitted by: Random Net person whose name I lost
Claim the major numbers (before sombedoy else jumps in again and
claims the slots for his foocd driver :-), install all the hooks that
are required.
While i've been at this, i've cleaned up some of the routines at the
end of i386/conf.c; all the importers of the latest CDROM drivers
forgot to fill in the appropriate information. The `ata' driver
(vapourware?) does only occupy a slot in the bdevsw[] array, btw.
The actual import of the code does require a minor change in the SCSI
subsystem, and i want to have this reviewed by Peter first, so it will
be deferred for some days. The driver is already working for me
though.
Submitted by: akiyama@kme.mei.co.jp (Shunsuke Akiyama)
user has entered a bogus kernel name in the first place).
Also fix the broken #ifdef FORCE_COMCONSOLE, it has been disabled by
accident. (NB: the keyboard probe remains disabled however.)
Few cosmetic fixes (declare functions to be void instead of int),
while i've been at this.
Pointed out by: wosch@cs.tu-berlin.de (Wolfram Schneider), for the init bug
serial_putchar() always hung if it was called and the serial port existed,
so booting with -h hung when the above bug was fixed. Previously, setting
-h did nothing but -h was sometimes the default due to the stack garbage
bug.
Submitted by: DI. Christian Gusenbauer <cg@scotty.edvz.uni-linz.ac.at>
The `howto' arg to boot() was not supplied, so it was stack garbage (actually
the return address in the boot program). I didn't use the submitted fix.
Change the interfaces of these functions to save space. The code
that takes the least amount of space is often the opposite to what
you might expect. E.g., it helps to waste a few bytes passing
pointers so that the compiler can't see that certain addresses
are identical (gcc likes to waste space by reloading fat constants
even when the constant is already in a register).
Rewrite getbootdev() to save 80 bytes of space and to make it less
ugly. 32 bytes were saved simply by omitting the continue statements
in the pseudo-switch.
recently introduced bloat in just 2 calls to biosread(), although
very little in calls to putc() and serial_putc(). Gcc produces
amazingly bad code for unnecessary conversions. E.g., if it has
`int x' in register %edx and wants to pass a char, then it could
simply push %edx and access only one byte in the callee. Instead,
it sometimes unnecessarily spills %edx; it always sign extends
%edx and pushes the result.
Remove useless `extern' in function prototypes.
Remove unused declaration of `end'.
Declare pbzero() and pcpy() like the library bzero and bcopy().
Declare printf() properly.
do fit, and beeping in case of an overflow.
. Drop a comment about the ``FORCE_COMCONSOLE'' option into
README.serial.
. Increase the name buffer for the root directory from 100 bytes
to 8 KB; this is in no way ideal, but (IMHO) the best that can
be done by now. People did encounter problems with their root
dir name listing overflowing the allocated buffer space. Once
we've got the three-stage boot, we should implement some basic
malloc(). Swap space is already getting tight now, perhaps the
swap should go into another 64 KB segment instead.
. Make the keyboard probe less paranoid. It should not give up in
case of a keyboard that's continuously demanding RESEND's. Even
though the keyboard reset apparently has not been reported to be
complete, it's at the very least proven that there IS something
like a keyboard available.
This solves problems with the ``Gateway-2000 AllKey programmable''
(sp?) keyboard, that experienced a total hang with the previous
probe.
Thanks goes to Scott Blachowicz <scott@statsci.com> for his
extensive testing of my various interim (debugging) bootblocks
to get this working.
interested parties.
Make the loader refuse to load anything below 1 MB -- we didn't
support it since FreeBSD 2.0R. Avoid gratuitously wiping out the BIOS
variables or the loader.
o Fix the keyboard probe to properly wait for the ready bit before
sending a command to the keyboard controller. This should avoid the
problems some people are experiencing where the boot blocks hang the
system during keyboard probe. (It does solve it for me.)
o Fix a bug that effectively prevented the boot blocks from ever
passing control to the serial console. [while(--retries) instead of
while(retries--)]
o Gratuitously reduced the keyboard probe timeout from 500 to 5
seconds. :)
o Introduced a new option ``FORCE_COMCONSOLE'' as a commented-out
example in the Makefile, to force the usage of a serial console
regardless of a keyboard being connected or not.
o Moved all external declarations to boot.h, declared all functions
there, and ANSIfied all function declarations/definitions.
(printf() remains bogus, however -- i'm too lazy to fix this.)
We're in the ninetees, dunno why we should still support compilers
from the 70's.
at least one user out there who's system won't autoboot from the
serial console because of what sounds like 'phantom keystrokes'
making the timeout timer trip. I've tried to solve this by
adding an extra call to init_serial() right before the 'Boot:'
prompt is printed (done only if RB_SERIAL is set) to hopefully
make sure that the input buffer is clear. Unfortunately, the fellow
is in Germany and I haven't heard back from him yet. I haven't
been able to duplicate this problem on my hardware, so this is
a stab in the dark. At the very least, it shouldn't hurt anything.
I'm not exactly sure why all the inb/outw stuff got added to netboot.h
and I'd be happy if someone like Martin or Bruce could take a look at it!
Submitted by: "Serge A. Babkin" <babkin@hq.icb.chel.su>
Install the biosboot as /usr/mdec/boot[12]
Make the traditional links from [swf]dboot and boot[swf]d to boot[12] files.
Install dosboot as /usr/mdec/boot/fbsdboot.exe
Feb. 10th snapshot. The keyboard probe in the bootblock seems to
have been singled out as the cause of these problems, so I've beefed it
up alittle. This pushes us right up to the edge of the size limit:
the second stage boot is now 7152 bytes in size, just 8 bytes under
the wire. On the other hand, the new probe now does almost exactly
what syscons does, so hopefully this will do the trick. It seems
to work properly on my hardware, but then so did the old probe.
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!
