The last half year I've been working on a replacement TTY layer for the
FreeBSD kernel. The new TTY layer was designed to improve the following:
- Improved driver model:
The old TTY layer has a driver model that is not abstract enough to
make it friendly to use. A good example is the output path, where the
device drivers directly access the output buffers. This means that an
in-kernel PPP implementation must always convert network buffers into
TTY buffers.
If a PPP implementation would be built on top of the new TTY layer
(still needs a hooks layer, though), it would allow the PPP
implementation to directly hand the data to the TTY driver.
- Improved hotplugging:
With the old TTY layer, it isn't entirely safe to destroy TTY's from
the system. This implementation has a two-step destructing design,
where the driver first abandons the TTY. After all threads have left
the TTY, the TTY layer calls a routine in the driver, which can be
used to free resources (unit numbers, etc).
The pts(4) driver also implements this feature, which means
posix_openpt() will now return PTY's that are created on the fly.
- Improved performance:
One of the major improvements is the per-TTY mutex, which is expected
to improve scalability when compared to the old Giant locking.
Another change is the unbuffered copying to userspace, which is both
used on TTY device nodes and PTY masters.
Upgrading should be quite straightforward. Unlike previous versions,
existing kernel configuration files do not need to be changed, except
when they reference device drivers that are listed in UPDATING.
Obtained from: //depot/projects/mpsafetty/...
Approved by: philip (ex-mentor)
Discussed: on the lists, at BSDCan, at the DevSummit
Sponsored by: Snow B.V., the Netherlands
dcons(4) fixed by: kan
features of CPUs like reading/writing machine-specific registers,
retrieving cpuid data, and updating microcode.
- Add cpucontrol(8) utility, that provides userland access to
the features of cpuctl(4).
- Add subsequent manpages.
The cpuctl(4) device operates as follows. The pseudo-device node cpuctlX
is created for each cpu present in the systems. The pseudo-device minor
number corresponds to the cpu number in the system. The cpuctl(4) pseudo-
device allows a number of ioctl to be preformed, namely RDMSR/WRMSR/CPUID
and UPDATE. The first pair alows the caller to read/write machine-specific
registers from the correspondent CPU. cpuid data could be retrieved using
the CPUID call, and microcode updates are applied via UPDATE.
The permissions are inforced based on the pseudo-device file permissions.
RDMSR/CPUID will be allowed when the caller has read access to the device
node, while WRMSR/UPDATE will be granted only when the node is opened
for writing. There're also a number of priv(9) checks.
The cpucontrol(8) utility is intened to provide userland access to
the cpuctl(4) device features. The utility also allows one to apply
cpu microcode updates.
Currently only Intel and AMD cpus are supported and were tested.
Approved by: kib
Reviewed by: rpaulo, cokane, Peter Jeremy
MFC after: 1 month
As clearly mentioned on the mailing lists, there is a list of drivers
that have not been ported to the MPSAFE TTY layer yet. Remove them from
the kernel configuration files. This means people can now still use
these drivers if they explicitly put them in their kernel configuration
file, which is good.
People should keep in mind that after August 10, these drivers will not
work anymore. Even though owners of the hardware are capable of getting
these drivers working again, I will see if I can at least get them to a
compilable state (if time permits).
The uart(4) driver has the advantage of supporting a wider variety of
hardware on a greater amount of platforms. This driver has already been
the standard on platforms such as ia64, powerpc and sparc64.
I've decided not to change anything on pc98. I'd rather let people from
the pc98 team look at this.
Approved by: philip (mentor), marcel
parts relied on the now removed NET_NEEDS_GIANT.
Most of I4B has been disconnected from the build
since July 2007 in HEAD/RELENG_7.
This is what was removed:
- configuration in /etc/isdn
- examples
- man pages
- kernel configuration
- sys/i4b (drivers, layers, include files)
- user space tools
- i4b support from ppp
- further documentation
Discussed with: rwatson, re
Note this includes changes to all drivers and moves some device firmware
loading to use firmware(9) and a separate module (e.g. ral). Also there
no longer are separate wlan_scan* modules; this functionality is now
bundled into the wlan module.
Supported by: Hobnob and Marvell
Reviewed by: many
Obtained from: Atheros (some bits)
to detect (or load) kernel NLM support in rpc.lockd. Remove the '-k'
option to rpc.lockd and make kernel NLM the default. A user can still
force the use of the old user NLM by building a kernel without NFSLOCKD
and/or removing the nfslockd.ko module.
frequency generation and what frequency the generated was anyones
guess.
In general the 32.768kHz RTC clock x-tal was the best, because that
was a regular wrist-watch Xtal, whereas the X-tal generating the
ISA bus frequency was much lower quality, often costing as much as
several cents a piece, so it made good sense to check the ISA bus
frequency against the RTC clock.
The other relevant property of those machines, is that they
typically had no more than 16MB RAM.
These days, CPU chips croak if their clocks are not tightly within
specs and all necessary frequencies are derived from the master
crystal by means if PLL's.
Considering that it takes on average 1.5 second to calibrate the
frequency of the i8254 counter, that more likely than not, we will
not actually use the result of the calibration, and as the final
clincher, we seldom use the i8254 for anything besides BEL in
syscons anyway, it has become time to drop the calibration code.
If you need to tell the system what frequency your i8254 runs,
you can do so from the loader using hw.i8254.freq or using the
sysctl kern.timecounter.tc.i8254.frequency.
While the KSE project was quite successful in bringing threading to
FreeBSD, the M:N approach taken by the kse library was never developed
to its full potential. Backwards compatibility will be provided via
libmap.conf for dynamically linked binaries and static binaries will
be broken.
cards:
o RocketRAID 172x series
o RocketRAID 174x series
o RocketRAID 2210
o RocketRAID 222x series
o RocketRAID 2240
o RocketRAID 230x series
o RocketRAID 231x series
o RocketRAID 232x series
o RocketRAID 2340
o RocketRAID 2522
Many thanks to Highpoint for their continued support of FreeBSD.
Submitted by: Highpoint
- Introduce per-architecture stack_machdep.c to hold stack_save(9).
- Introduce per-architecture machine/stack.h to capture any common
definitions required between db_trace.c and stack_machdep.c.
- Add new kernel option "options STACK"; we will build in stack(9) if it is
defined, or also if "options DDB" is defined to provide compatibility
with existing users of stack(9).
Add new stack_save_td(9) function, which allows the capture of a stacktrace
of another thread rather than the current thread, which the existing
stack_save(9) was limited to. It requires that the thread be neither
swapped out nor running, which is the responsibility of the consumer to
enforce.
Update stack(9) man page.
Build tested: amd64, arm, i386, ia64, powerpc, sparc64, sun4v
Runtime tested: amd64 (rwatson), arm (cognet), i386 (rwatson)
Currently, Giant is not too much contented so that it is ok to treact it
like any other mutexes.
Please don't forget to update your own custom config kernel files.
Approved by: cognet, marcel (maintainers of arches where option is
not enabled at the moment)
This includes:
o mtree (for legal/intel_wpi)
o manpage for i386/amd64 archs
o module for i386/amd64 archs
o NOTES for i386/amd64 archs
Approved by: mlaier (comentor)
refactored it to be a generic device.
Instead of being part of the standard kernel, there is now a 'nvram' device
for i386/amd64. It is in DEFAULTS like io and mem, and can be turned off
with 'nodevice nvram'. This matches the previous behavior when it was
first committed.
and newer CPUs (including Core 2 and Core / Core 2 based Xeons). The
driver attaches to each cpu device and creates a sysctl node in that
device's sysctl context (dev.cpu.N.temperature). When invoked, the
handler binds to the appropriate CPU to ensure a correct reading.
Submitted by: Rui Paulo <rpaulo@fnop.net>
Sponsored by: Google Summer of Code 2007
Tested by: des, marcus, Constantine A. Murenin, Ian FREISLICH
Approved by: re (kensmith)
MFC after: 3 weeks
the 7.0 timeframe.
This is needed because I4B is not locked and NET_NEEDS_GIANT goes away.
The plan is to lock I4B and bring everything back for 7.1.
Approved by: re (kensmith)
more exposure. The current state of SCTP implementation is
considered to be ready for 32-bit platforms, but still need some
work/testing on 64-bit platforms.
Approved by: re (kensmith)
Discussed with: rrs
making the relevant files standard. This avoids duplication and
makes it easier to override/disable unwanted schemes. Since ARM
doesn't have a DEFAULTS configuration file, leave the source
files for the BSD and MBR partitioning schemes in files.arm for
now.
Note on dcons:
To enable dcons in kernel, put the following lines in /boot/loader.conf.
You may also want to enable dcons in /etc/ttys.
boot_multicons="YES"
#Force dcons to be the high-level console if a firewire bus presents.
#hw.firewire.dcons_crom.force_console=1
FireWire/dcons support in loader will come shortly.
(i386/amd64 only)
partitioning class that supports multiple schemes. Current
schemes supported are APM (Apple Partition Map) and GPT.
Change all GEOM_APPLE anf GEOM_GPT options into GEOM_PART_APM
and GEOM_PART_GPT (resp).
The ctlreq interface supports verbs to create and destroy
partitioning schemes on a disk; to add, delete and modify
partitions; and to commit or undo changes made.
it as a default.
For the record, the KDTRACE option caused _no_ additional source files
to be compiled in; certainly no CDDL source files. All it did was to
allow existing BSD licensed kernel files to include one or more CDDL
header files.
By removing this from DEFAULTS, the onus is on a kernel builder to add
the option to the kernel config, possibly by including GENERIC and
customising from there. It means that DTrace won't be a feature
available in FreeBSD by default, which is the way I intended it to be.
Without this option, you can't load the dtrace module (which contains
the dtrace device and the DTrace framework). This is equivalent to
requiring an option in a kernel config before you can load the linux
emulation module, for example.
I think it is a mistake to have DTrace ported to FreeBSD, but not
to have it available to everyone, all the time. The only exception
to this is the companies which distribute systems with FreeBSD embedded.
Those companies will customise their systems anyway. The KDTRACE
option was intended for them, and only them.
adds the hooks that DTrace modules register with, and adds a few functions
which have the dtrace_ prefix to allow the DTrace FBT (function boundary
trace) provider to avoid tracing because they are called from the DTtrace
probe context.
Unlike other forms of tracing and debug, DTrace support in the kernel
incurs negligible run-time cost.
I think the only reason why anyone wouldn't want to have kernel support
enabled for DTrace would be due to the license (CDDL) under which DTrace
is released.
The 'nooption' kernel config entry has to be used to turn KSE off now.
This isn't my preferred way of dealing with this, but I'll defer to
scottl's experience with the io/mem kernel option change and the grief
experienced over that.
Submitted by: scottl@
except sun4v.
This change makes the transition from a default to an option more
transparent and is an attempt to head off all the compliants that are
likely from people who don't read UPDATING, based on experience with
the io/mem change.
Submitted by: scottl@
unsuspecting users.
- Add a comment in NOTES about experimental status of SCHED_ULE.
- Make warning about experimental status in sched_ule(4) a bit
stronger.
Suggested and reviewed by: dougb
Discussed on: developers
MFC after: 3 days
- Split out the communication protocols into their own files and use
a couple of function pointers in the softc that the commuication
protocols setup in their own attach routine.
- Add support for the SSIF interface (talking to IPMI over SMBus).
- Add an ACPI attachment.
- Add a PCI attachment that attaches to devices with the IPMI interface
subclass.
- Split the ISA attachment out into its own file: ipmi_isa.c.
- Change the code to probe the SMBIOS table for an IPMI entry to just use
pmap_mapbios() to map the table in rather than trying to setup a fake
resource on an isa device and then activating the resource to map in the
table.
- Make bus attachments leaner by adding attach functions for each
communication interface (ipmi_kcs_attach(), ipmi_smic_attach(), etc.)
that setup per-interface data.
- Formalize the model used by the driver to handle requests by adding an
explicit struct ipmi_request object that holds the state of a given
request and reply for the entire lifetime of the request. By bundling
the request into an object, it is easier to add retry logic to the various
communication backends (as well as eventually support BT mode which uses
a slightly different message format than KCS, SMIC, and SSIF).
- Add a per-softc lock and remove D_NEEDGIANT as the driver is now MPSAFE.
- Add 32-bit compatibility ioctl shims so you can use a 32-bit ipmitool
on FreeBSD/amd64.
- Add ipmi(4) to i386 and amd64 NOTES.
Submitted by: ambrisko (large portions of 2 and 3)
Sponsored by: IronPort Systems, Yahoo!
MFC after: 6 days
and pc98 MD files. Remove nodevice and nooption lines specific
to sio(4) from ia64, powerpc and sparc64 NOTES. There were no
such lines for arm yet.
sio(4) is usable on less than half the platforms, not counting
a future mips platform. Its presence in MI files is therefore
increasingly becoming a burden.
This driver was ported from OpenBSD by Shigeaki Tagashira
<shigeaki@se.hiroshima-u.ac.jp> and posted at
http://www.se.hiroshima-u.ac.jp/~shigeaki/software/freebsd-nfe.html
It was additionally cleaned up by me.
It is still a work-in-progress and thus is purposefully not in GENERIC.
And it conflicts with nve(4), so only one should be loaded.
in 1999, and there are changes to the sysctl names compared to PR,
according to that discussion. The description is in sys/conf/NOTES.
Lines in the GENERIC files are added in commented-out form.
I'll attach the test script I've used to PR.
PR: kern/14584
Submitted by: babkin
an explicit comment that it's needed for the linuxolator. This is not the
case anymore. For all other architectures there was only a "KEEP THIS".
I'm (and other people too) running a COMPAT_43-less kernel since it's not
necessary anymore for the linuxolator. Roman is running such a kernel for a
for longer time. No problems so far. And I doubt other (newer than ia32
or alpha) architectures really depend on it.
This may result in a small performance increase for some workloads.
If the removal of COMPAT_43 results in a not working program, please
recompile it and all dependencies and try again before reporting a
problem.
The only place where COMPAT_43 is needed (as in: does not compile without
it) is in the (outdated/not usable since too old) svr4 code.
Note: this does not remove the COMPAT_43TTY option.
Nagging by: rdivacky
I picked it up again. The scheduler is forked from ULE, but the
algorithm to detect an interactive process is almost completely
different with ULE, it comes from Linux paper "Understanding the
Linux 2.6.8.1 CPU Scheduler", although I still use same word
"score" as a priority boost in ULE scheduler.
Briefly, the scheduler has following characteristic:
1. Timesharing process's nice value is seriously respected,
timeslice and interaction detecting algorithm are based
on nice value.
2. per-cpu scheduling queue and load balancing.
3. O(1) scheduling.
4. Some cpu affinity code in wakeup path.
5. Support POSIX SCHED_FIFO and SCHED_RR.
Unlike scheduler 4BSD and ULE which using fuzzy RQ_PPQ, the scheduler
uses 256 priority queues. Unlike ULE which using pull and push, the
scheduelr uses pull method, the main reason is to let relative idle
cpu do the work, but current the whole scheduler is protected by the
big sched_lock, so the benefit is not visible, it really can be worse
than nothing because all other cpu are locked out when we are doing
balancing work, which the 4BSD scheduelr does not have this problem.
The scheduler does not support hyperthreading very well, in fact,
the scheduler does not make the difference between physical CPU and
logical CPU, this should be improved in feature. The scheduler has
priority inversion problem on MP machine, it is not good for
realtime scheduling, it can cause realtime process starving.
As a result, it seems the MySQL super-smack runs better on my
Pentium-D machine when using libthr, despite on UP or SMP kernel.
the arm to compile without all the extras that don't appear, at least
not in the flavors of ARM I deal with. This helps us save about 100k.
If I've botched the available devices on a platform, please let me
know and I'll correct ASAP.
o Properly use rman(9) to manage resources. This eliminates the
need to puc-specific hacks to rman. It also allows devinfo(8)
to be used to find out the specific assignment of resources to
serial/parallel ports.
o Compress the PCI device "database" by optimizing for the common
case and to use a procedural interface to handle the exceptions.
The procedural interface also generalizes the need to setup the
hardware (program chipsets, program clock frequencies).
o Eliminate the need for PUC_FASTINTR. Serdev devices are fast by
default and non-serdev devices are handled by the bus.
o Use the serdev I/F to collect interrupt status and to handle
interrupts across ports in priority order.
o Sync the PCI device configuration to include devices found in
NetBSD and not yet merged to FreeBSD.
o Add support for Quatech 2, 4 and 8 port UARTs.
o Add support for a couple dozen Timedia serial cards as found
in Linux.
to COMPAT_43TTY.
Add COMPAT_43TTY to NOTES and */conf/GENERIC
Compile tty_compat.c only under the new option.
Spit out
#warning "Old BSD tty API used, please upgrade."
if ioctl_compat.h gets #included from userland.
- S3 Savage driver ported.
- Added support for ATI_fragment_shader registers for r200.
- Improved r300 support, needed for latest r300 DRI driver.
- (possibly) r300 PCIE support, needs X.Org server from CVS.
- Added support for PCI Matrox cards.
- Software fallbacks fixed for Rage 128, which used to render badly or hang.
- Some issues reported by WITNESS are fixed.
- i915 module Makefile added, as the driver may now be working, but is untested.
- Added scripts for copying and preprocessing DRM CVS for inclusion in the
kernel. Thanks to Daniel Stone for getting me started on that.
via the DEFAULTS kernel configs. This allows folks to turn it that option
off in the kernel configs if desired without having to hack the source.
This is especially useful since PUC_FASTINTR hangs the kernel boot on my
ultra60 which has two uart(4) devices hung off of a puc(4) device.
I did not enable PUC_FASTINTR by default on powerpc since powerpc does not
currently allow sharing of INTR_FAST with non-INTR_FAST like the other
archs.
The following repo-copies were made (by Mark Murray):
sys/i386/isa/spkr.c -> sys/dev/speaker/spkr.c
sys/i386/include/speaker.h -> sys/dev/speaker/speaker.h
share/man/man4/man4.i386/spkr.4 -> share/man/man4/spkr.4
sio(4) will claim it. This change therefore only affects how ports
are handled when they are not claimed by sio(4), and in principle
will improve hardware support.
MFC after: 2 months
'device npx' (both of which aren't really optional right now) and
'device io' and 'device mem' (to preserve POLA for 4.x users upgrading
to 6.0) from GENERIC into DEFAULTS.
Requested by: scottl
Reviewed by: scottl
IPI_STOP IPIs.
- Change the i386 and amd64 MD IPI code to send an NMI if STOP_NMI is
enabled if an attempt is made to send an IPI_STOP IPI. If the kernel
option is enabled, there is also a sysctl to change the behavior at
runtime (debug.stop_cpus_with_nmi which defaults to enabled). This
includes removing stop_cpus_nmi() and making ipi_nmi_selected() a
private function for i386 and amd64.
- Fix ipi_all(), ipi_all_but_self(), and ipi_self() on i386 and amd64 to
properly handle bitmapped IPIs as well as IPI_STOP IPIs when STOP_NMI is
enabled.
- Fix ipi_nmi_handler() to execute the restart function on the first CPU
that is restarted making use of atomic_readandclear() rather than
assuming that the BSP is always included in the set of restarted CPUs.
Also, the NMI handler didn't clear the function pointer meaning that
subsequent stop and restarts could execute the function again.
- Define a new macro HAVE_STOPPEDPCBS on i386 and amd64 to control the use
of stoppedpcbs[] and always enable it for i386 and amd64 instead of
being dependent on KDB_STOP_NMI. It works fine in both the NMI and
non-NMI cases.
This kernel config briefly describes some of the major MAC policies
available on FreeBSD. The hope is that this will raise the awareness
about MAC and get more people interested.
Discussed with: scottl
chips are commonly found, it makes sense to have it in GENERIC. This
is a candidate for a RELENG_6 MFC.
Approved by; peter
Requested by: pav
Tested by: pav
by Vladimir Dergachev for inclusion in DRM CVS, with minor modifications for
FreeBSD CVS and the appropriate license from Nicolai Haehnle on r300_reg.h.
Fixes hangs when using r300.sf.net userland, tested on a Radeon 9600 on amd64.
* Add ichwd (The Intel EM64T folks have an ICH)
* Cosmetic comment syncs
* Merge cpufreq change over to NOTES
* add pbio (it compiles, but isn't useful since no boxes have ISA slots)
* copy ath settings (note: wlan disabled here since its in global NOTES)
* copy profiling, including fixing a previous i386->amd64 merge typo.
Approved by: re (blanket i386 <-> amd64 sync/convergence)
a regular IPI vector, but this vector is blocked when interrupts are disabled.
With "options KDB_STOP_NMI" and debug.kdb.stop_cpus_with_nmi set, KDB will
send an NMI to each CPU instead. The code also has a context-stuffing
feature which helps ddb extract the state of processes running on the
stopped CPUs.
KDB_STOP_NMI is only useful with SMP and complains if SMP is not defined.
This feature only applies to i386 and amd64 at the moment, but could be
used on other architectures with the appropriate MD bits.
Submitted by: ups
- Split core DRM routines back into their own module, rather than using the
nasty templated system like before.
- Development-class R300 support in radeon driver (requires userland pieces, of
course).
- Mach64 driver (haven't tested in a while -- my mach64s no longer fit in the
testbox). Covers Rage Pros, Rage Mobility P/M, Rage XL, and some others.
- i915 driver files, which just need to get drm_drv.c fixed to allow attachment
to the drmsub device. Covers i830 through i915 integrated graphics.
- savage driver files, which should require minimal changes to work. Covers the
Savage3D, Savage IX/MX, Savage 4, ProSavage.
- Support for color and texture tiling and HyperZ features of Radeon.
Thanks to: scottl (much p4 handholding)
Jung-uk Kim (helpful prodding)
PR: [1] kern/76879, [2] kern/72548
Submitted by: [1] Alex, lesha at intercaf dot ru
[2] Shaun Jurrens, shaun at shamz dot net
There are too many questions in freebsd-amd64@ about how to enable Linux
support that it seems a required piece of functionality. Thus we should
just have it on by default.
FreeBSD based on aue(4) it was picked by OpenBSD, then from OpenBSD ported
to NetBSD and finally NetBSD version merged with original one goes into
FreeBSD.
Obtained from: http://www.gank.org/freebsd/cdce/
NetBSD
OpenBSD
This is mentioned in the Handbook but it is not as obvious to new
users why bpf is needed compared to the other largely self-explanatory
items in GENERIC.
PR: conf/40855
MFC after: 1 week
where having this disabled was actually hurting us, since so many
BIOSes include legacy USB emulation that takes control of all usb
ports and only the ehci driver knows how to disable it.
from 4.x kernel config files. User's wishing to upgrade from 4.x to 6
will need to go through 5.x, or grab this script from there. These
scripts will remain in RELENG_5...
VT6122 gigabit ethernet chip and integrated 10/100/1000 copper PHY.
The vge driver has been added to GENERIC for i386, pc98 and amd64,
but not to sparc or ia64 since I don't have the ability to test
it there. The vge(4) driver supports VLANs, checksum offload and
jumbo frames.
Also added the lge(4) and nge(4) drivers to GENERIC for i386 and
pc98 since I was in the neighborhood. There's no reason to leave them
out anymore.
It can be switched back once 5.3 is tested and released. Also turn on
PREEMPTION as many of the stability problems with it have been fixed.
MT5: 3 days.
compile option. All FreeBSD packet filters now use the PFIL_HOOKS API and
thus it becomes a standard part of the network stack.
If no hooks are connected the entire packet filter hooks section and related
activities are jumped over. This removes any performance impact if no hooks
are active.
Both OpenBSD and DragonFlyBSD have integrated PFIL_HOOKS permanently as well.
with the COMPAT_LINUX32 option. This is largely based on the i386 MD Linux
emulations bits, but also builds on the 32-bit FreeBSD and generic IA-32
binary emulation work.
Some of this is still a little rough around the edges, and will need to be
revisited before 32-bit and 64-bit Linux emulation support can coexist in
the same kernel.
their own directory and module, leaving the MD parts in the MD
area (the MD parts _are_ part of the modules). /dev/mem and /dev/io
are now loadable modules, thus taking us one step further towards
a kernel created entirely out of modules. Of course, there is nothing
preventing the kernel from having these statically compiled.
NO_ADAPTIVE_MUTEXES. This option has been enabled by default on amd64 for
quite some time, and has been extensively tested on i386 and sparc64. It
shows measurable performance gains in many circumstances, and few negative
effects. It would be nice in t he future if adaptive mutexes actually went
to sleep after a certain amount of spinning, but that will require quite a
bit more testing.
known samples of broken chipsets that needed mixed mode in the first place
are so broken (ie: locks up) that we can't use IO APIC mode at all and it
needs to be turned off in the bios. So, the MIXED_MODE penalty on the
good chipsets gained nothing.
Approved by: re (scottl)
- turn on SMP in generic
- add 'device atpic' - this is unconditional on i386, but certain nvidia
based systems need to disable acpi because the reference bios seems to be
hosed. If acpi is disabled, we won't find the apic. amd64 has the
mptable code in a seperate compile option as well.
- turn sym back on, it doesn't fail to compile anymore.
Approved by: re
