Michael Brown [Tue, 20 Jul 2010 19:52:08 +0000 (20:52 +0100)]
[netdevice] Provide a test mechanism for discarding packets at random
Setting NETDEV_DISCARD_RATE to a non-zero value will cause one in
every NETDEV_DISCARD_RATE packets to be discarded at random on both
the transmit and receive datapaths, allowing the robustness of
upper-layer network protocols to be tested even in simulation
environments that provide wholly reliable packet transmission.
Stefan Hajnoczi [Fri, 2 Jul 2010 18:15:47 +0000 (19:15 +0100)]
[virtio] Replace virtio-net with native iPXE driver
This patch adds a native iPXE virtio-net driver and removes the legacy
Etherboot virtio-net driver. The main reasons for doing this are:
1. Multiple virtio-net NICs are now supported by iPXE. The legacy
driver kept global state and caused issues in virtual machines with
more than one virtio-net device.
2. Faster downloads. The native iPXE driver downloads 100 MB over
HTTP in 12s, the legacy Etherboot driver in 37s. This simple
benchmark uses KVM with tap networking and the Python
SimpleHTTPServer both running on the same host.
Changes to core virtio code reduce vring descriptors to 256 (QEMU uses
128 for virtio-blk and 256 for virtio-net) and change the opaque token
from u16 to void*. Lowering the descriptor count reduces memory
consumption. The void* opaque token change makes driver code simpler.
Signed-off-by: Stefan Hajnoczi <stefanha@gmail.com> Signed-off-by: Michael Brown <mcb30@ipxe.org>
Stefan Hajnoczi [Sun, 11 Jul 2010 07:52:57 +0000 (08:52 +0100)]
[errcode] Remove unused contrib/errcode scripts
The new errdb error code database is more accurate than the regular
expression-based errcode scripts. This patch removes errcode scripts
in favor of errdb.
The gpxebot.py script is no longer needed, gpxebot has been released
as a separate open source codebase:
[settings] Unregister the children when unregistering the parent
The DHCP settings registered as a child of the netdevice settings are
not unregistered anywhere. This prevents the netdevice from being
freed on shutdown.
Fix by automatically unregistering any child settings when the parent
settings are unregistered.
Modified-by: Michael Brown <mcb30@ipxe.org> Signed-off-by: Michael Brown <mcb30@ipxe.org>
Michael Brown [Thu, 15 Jul 2010 18:33:46 +0000 (19:33 +0100)]
[tcp] Treat ACKs as sent only when successfully transmitted
iPXE currently forces sending (i.e. sends a pure ACK even in the
absence of fresh data to send) only in response to packets that
consume sequence space or that lie outside of the receive window.
This ignores the possibility that a previous ACK was not actually sent
(due to, for example, the retransmission timer running).
This does not cause incorrect behaviour, but does cause unnecessary
retransmissions from our peer. For example:
1. Peer sends final data packet (ack 106 seq 521..523)
2. We send FIN (seq 106..107 ack 523)
3. Peer sends FIN (ack 106 seq 523..524)
4. We send nothing since retransmission timer is running for our FIN
5. Peer ACKs our FIN (ack 107 seq 524..524)
6. We send nothing since this packet consumes no sequence space
7. Peer retransmits FIN (ack 107 seq 523..524)
8. We ACK peer's FIN (seq 107..107 ack 524)
What should happen at step (6) is that we should ACK the peer's FIN,
since we can deduce that we have never sent this ACK.
Fix by maintaining an "ACK pending" flag that is set whenever we are
made aware that our peer needs an ACK (whether by consuming sequence
space or by sending a packet that appears out of order), and is
cleared only when the ACK packet has been transmitted.
Reported-by: Piotr Jaroszyński <p.jaroszynski@gmail.com> Signed-off-by: Michael Brown <mcb30@ipxe.org>
Michael Brown [Thu, 15 Jul 2010 17:57:34 +0000 (18:57 +0100)]
[tcp] Use a dedicated timer for the TIME_WAIT state
iPXE currently repurposes the retransmission timer to hold the TCP
connection in the TIME_WAIT state (i.e. waiting for up to 2*MSL in
case we are required to re-ACK our peer's FIN due to a lost ACK).
However, the fact that this timer is running will prevent such an ACK
from ever being sent, since the logic in tcp_xmit() assumes that a
running timer indicates that we ourselves are waiting for an ACK and
so blocks the transmission. (We always wait for an ACK before sending
our next packet, to keep our transmit data path as simple as
possible.)
Fix by using an entirely separate timer for the TIME_WAIT state, so
that packets can still be sent.
Reported-by: Piotr Jaroszyński <p.jaroszynski@gmail.com> Signed-off-by: Michael Brown <mcb30@ipxe.org>
Michael Brown [Wed, 14 Jul 2010 17:29:16 +0000 (18:29 +0100)]
[build] Speed up rebuilding on header file changes
Split src_template into deps_template (which handles the definition of
foo_DEPS) and rules_template (which handles the rules referencing
foo_DEPS). The rules_template is not affected by any included header
files and so does not need to be reprocessed following a change to an
included header file.
This reduces the time required to rebuild the Makefile rules following
a change to stdint.h by around 45%, at a cost of increasing the time
required to rebuild after a "make veryclean" by around 3%.
Michael Brown [Wed, 14 Jul 2010 15:14:29 +0000 (16:14 +0100)]
[build] Avoid unnecessary "rm" and "touch" in dependency generation
Speed up dependency generation by omitting the totally unnecessary
"rm" and "touch" commands. This reduces the time taken to generate
dependencies by around 6%.
Stefan Hajnoczi [Wed, 14 Jul 2010 09:13:44 +0000 (10:13 +0100)]
[build] Mark weak functions noinline
Weak functions whose visibility is hidden may be inlined due to a bug
in GCC. Explicitly mark weak functions noinline to work around the
problem.
This makes the PXE_MENU config option work again, the PXE boot menu
was never being called because the compiler inlined a weak stub
function.
The GCC bug was identified and fixed by Richard Sandiford
<rdsandiford@googlemail.com> but in the meantime iPXE needs to
implement a workaround.
Reported-by: Steve Jones <steve@squaregoldfish.co.uk> Reported-by: Shao Miller <shao.miller@yrdsb.edu.on.ca> Suggested-by: Joshua Oreman <oremanj@rwcr.net> Signed-off-by: Stefan Hajnoczi <stefanha@gmail.com> Modified-by: Michael Brown <mcb30@ipxe.org> Signed-off-by: Michael Brown <mcb30@ipxe.org>
Michael Brown [Wed, 14 Jul 2010 11:01:20 +0000 (12:01 +0100)]
[debug] Expose pause() and more() debugging functions
Include the pause() and more() debugging functions within the general
iPXE debugging framework, by introducing DBGxxx_PAUSE() and
DBGxxx_MORE() macros.
Michael Brown [Wed, 14 Jul 2010 10:27:42 +0000 (11:27 +0100)]
[console] Remove never-used putline() method
putline() was introduced back in 2007 for a feature that was never
committed. No console driver implements it and no code calls it, so
remove it from struct console_driver.
image_set_cmdline() strdup()s cmdline, which free_image() doesn't
clean up.
Signed-off-by: Piotr Jaroszyński <p.jaroszynski@gmail.com> Signed-off-by: Stefan Hajnoczi <stefanha@gmail.com> Signed-off-by: Michael Brown <mcb30@ipxe.org>
Glenn Brown [Wed, 23 Jun 2010 20:18:36 +0000 (13:18 -0700)]
[myri10ge] Add NonVolatile Option (nvo) support
Add NonVolatile Option (nvo) and NonVolatile Storage (nvs) support to
the myri10ge driver using the EEPROM read/write mechanism provided by
the NIC's Vendor Specific PCI capability.
The myri10ge NIC is capabile of storing 64KB or more of nonvolatile
options, but this patch advertises only 512 bytes of nvo storage
because iPXE malloc's a buffer matching the total size we advertise.
512 is plenty without wasting malloc'd memory. (The 2 other drivers
currently supporting nvo advertise 256 bytes or less.)
Signed-off-by: Stefan Hajnoczi <stefanha@gmail.com> Signed-off-by: Michael Brown <mcb30@ipxe.org>
Make Ctrl-D delete a setting, because the Text User Interface (tui)
previously provided no way to delete a setting. Also, update the
on-screen instructions to describe the new feature. Deleting settings
is especially important for settings stored in precious nonvolatile
storage.
Signed-off-by: Stefan Hajnoczi <stefanha@gmail.com> Signed-off-by: Michael Brown <mcb30@ipxe.org>
Glenn Brown [Wed, 23 Jun 2010 20:18:34 +0000 (13:18 -0700)]
[settings] Enable jump scroll in config UI
Implement jump scrolling with "..." displayed where the settings list
continues off-screen, because there are now too many settings to fit
on screen in the "config ..." text user interface.
Signed-off-by: Stefan Hajnoczi <stefanha@gmail.com> Signed-off-by: Michael Brown <mcb30@ipxe.org>
Michael Brown [Thu, 24 Jun 2010 18:03:04 +0000 (19:03 +0100)]
[romprefix] Do not check for BBS compatibility
The existence and usage of the BEV entry point is covered by the PnP
spec, not the BBS spec; the BBS spec merely describes a policy for
selecting the boot device order. iPXE should therefore check only for
a PnP BIOS in order to decide whether or not to hook INT19.
Michael Brown [Thu, 24 Jun 2010 16:20:35 +0000 (17:20 +0100)]
[build] Fix broken build caused by implied dependency upon "perl"
Commit ea12dc0 ("[build] Avoid hard-coding the path to perl")
introduced a build failure for fully clean trees (e.g. after running
"make veryclean"), since the dependency upon $(PARSEROM) now includes
a dependency upon "perl" (which doesn't exist) rather than upon
"/usr/bin/perl" (which does exist).
There should of course be no dependency upon the perl binary at all;
the dependency should be upon "./util/parserom.pl" alone.
Fix by removing the $(PERL) from the definition of Perl-based utility
paths, and adding $(PERL) at the point of usage.
Reported-by: Stefan Hajnoczi <stefanha@gmail.com> Signed-off-by: Michael Brown <mcb30@ipxe.org>
Michael Brown [Thu, 24 Jun 2010 00:23:00 +0000 (01:23 +0100)]
[build] Avoid hard-coding the path to perl
The path "/usr/bin/perl" has been hard-coded since Etherboot 5.1, for
no discernible reason. Use just "perl" instead to fix the
inconsistency and allow building on systems with Perl installed
outside of /usr/bin.
Reported-by: Gabor Z. Papp <gzp@papp.hu> Signed-off-by: Michael Brown <mcb30@ipxe.org>
Andrei Faur [Tue, 22 Jun 2010 16:41:58 +0000 (19:41 +0300)]
[r8169] Remove driver cfg lookup, use pci_device_id->driver_data instead
This patch removes the cfg lookup made in the r8169 driver and
replaces it with equivalent information found in the driver_data field
of the pci_device_id structure.
Signed-off-by: Andrei Faur <da3drus@gmail.com> Signed-off-by: Michael Brown <mcb30@ipxe.org>
Michael Brown [Tue, 22 Jun 2010 18:12:40 +0000 (19:12 +0100)]
[interface] Allow for non-pass-through interface methods
xfer_vredirect() should not be allowed to propagate to a pass-through
interface. For example, when an HTTPS connection is opened, the
redirect message should cause the TLS layer to reopen the TCP socket,
rather than causing the HTTP layer to disconnect from the TLS layer.
Fix by allowing for non-pass-through interface methods, and setting
xfer_vredirect() to be one such method.
This is slightly ugly, in that it complicates the notion of an
interface method call by adding a "pass-through" / "non-pass-through"
piece of metadata. However, the only current user of xfer_vredirect()
is iscsi.c, which uses it only because we don't yet have an
ioctl()-style call for retrieving the underlying socket address.
The new interface infrastructure allows for such a call to be created,
at which time this sole user of xfer_vredirect() can be removed,
xfer_vredirect() can cease to be an interface method and become simply
a wrapper around xfer_vreopen(), and the concept of a non-pass-through
interface method can be reverted.
Michael Brown [Wed, 16 Jun 2010 00:31:29 +0000 (01:31 +0100)]
[interface] Convert all data-xfer interfaces to generic interfaces
Remove data-xfer as an interface type, and replace data-xfer
interfaces with generic interfaces supporting the data-xfer methods.
Filter interfaces (as used by the TLS layer) are handled using the
generic pass-through interface capability. A side-effect of this is
that deliver_raw() no longer exists as a data-xfer method. (In
practice this doesn't lose any efficiency, since there are no
instances within the current codebase where xfer_deliver_raw() is used
to pass data to an interface supporting the deliver_raw() method.)
Michael Brown [Thu, 12 Jun 2008 20:47:19 +0000 (21:47 +0100)]
[interface] Convert all job-control interfaces to generic interfaces
Remove job-control as an interface type, and replace job-control
interfaces with generic interfaces supporting the close() method.
(Both done() and kill() are absorbed into the function of close();
kill() is merely close(-ECANCELED).)
Michael Brown [Thu, 12 Jun 2008 18:43:25 +0000 (19:43 +0100)]
[interface] Expand object interface to allow for polymorphic interfaces
We have several types of object interface at present (data-xfer, job
control, name resolution), and there is some duplication of
functionality between them. For example, job_done(), job_kill() and
xfer_close() are almost isomorphic to each other.
This updated version of the object interface mechanism allows for each
interface to export an arbitrary list of supported operations.
Advantages include:
Operations methods now receive a pointer to the object, rather than
a pointer to the interface. This allows an object to, for example,
implement a single close() method that can handle close() operations
from any of its exposed interfaces.
The close() operation is implemented as a generic operation (rather
than having specific variants for data-xfer, job control, etc.).
This will allow functions such as monojob_wait() to be used to wait
for e.g. a name resolution to complete.
The amount of boilerplate code required in objects is reduced, not
least because it is no longer necessary to include per-interface
methods that simply use container_of() to derive a pointer to the
object and then tail-call to a common per-object method.
The cost of adding new operations is reduced; adding a new data-xfer
operation such as stat() no longer incurs the penalty of adding a
.stat member to the operations table of all existing data-xfer
interfaces.
The data-xfer, job control and name resolution interfaces have not yet
been updated to use the new interface mechanism, but the code will
still compile and run.
Michael Brown [Fri, 13 Jun 2008 02:39:22 +0000 (03:39 +0100)]
[process] Hold reference to process during call to step()
It is conceivable that the process may terminate during the execution
of step(). If nothing else holds a reference to the containing
object, this would cause the object to be freed prior to returning
from step().
Add a ref_get()/ref_put() around the call to ->step() to prevent this
from happening.
Guo-Fu Tseng [Fri, 4 Jun 2010 14:23:15 +0000 (22:23 +0800)]
[jme] Fix refill behavior
After changing the driver to refill after feed, if any error occurs a
non-contiguous empty buffer will be introduced in the ring due to my
reuse-buffer-when-error implementation.
Reported-by: Marty Connor <mdc@etherboot.org> Signed-off-by: Guo-Fu Tseng <cooldavid@cooldavid.org> Signed-off-by: Stefan Hajnoczi <stefanha@gmail.com> Signed-off-by: Michael Brown <mcb30@ipxe.org>
Guo-Fu Tseng [Mon, 31 May 2010 22:09:02 +0000 (06:09 +0800)]
[jme] Add JMicron Ethernet driver
A new driver for JMicron Ethernet controller.
Reviewed-by: Joshua Oreman <oremanj@rwcr.net> Reviewed-by: Michael Brown <mbrown@fensystems.co.uk> Reviewed-by: Marty Connor <mdc@etherboot.org> Signed-off-by: Guo-Fu Tseng <cooldavid@cooldavid.org> Modified-by: Michael Brown <mcb30@ipxe.org> Signed-off-by: Michael Brown <mcb30@ipxe.org>
Geoff Lywood [Fri, 28 May 2010 03:08:28 +0000 (20:08 -0700)]
[efi] Add the "snpnet" driver
Add a new network driver that consumes the EFI Simple Network
Protocol. Also add a bus driver that can find the Simple Network
Protocol that iPXE was loaded from; the resulting behavior is similar
to the "undionly" driver for BIOS systems.
The linker chooses to look for _start first and always picks
efidrvprefix.o to satisfy it (probably because it's earlier in the
archive) which causes a multiple definition error when the linker
later has to pick efiprefix.o for other symbols.
Fix by using EFI-specific TGT_LD_FLAGS with an explicit entry point.
Signed-off-by: Piotr Jaroszyński <p.jaroszynski@gmail.com> Signed-off-by: Joshua Oreman <oremanj@rwcr.net> Modified-by: Michael Brown <mcb30@ipxe.org> Signed-off-by: Michael Brown <mcb30@ipxe.org>
Apart from format specifier fixes there are two changes in proper code:
- Change type of regs in skge_hw to unsigned long
- Cast result of sizeof in myri10ge to uint32_t
Both don't change anything for i386 and should be fine on x86_64.
Signed-off-by: Piotr Jaroszyński <p.jaroszynski@gmail.com> Signed-off-by: Joshua Oreman <oremanj@rwcr.net> Signed-off-by: Michael Brown <mcb30@ipxe.org>
Joshua Oreman [Wed, 26 May 2010 21:22:03 +0000 (14:22 -0700)]
[dhcp] Don't consider invalid offers to be duplicates
This fixes a regression in BOOTP support; since BOOTP requests often
have the `siaddr' field set to 0.0.0.0, they would be considered
duplicates of the first zeroed-out offer slot.
Signed-off-by: Joshua Oreman <oremanj@rwcr.net> Signed-off-by: Michael Brown <mcb30@ipxe.org>
Joshua Oreman [Thu, 27 May 2010 00:52:44 +0000 (17:52 -0700)]
[build] Use weak definitions instead of weak declarations
This removes the need for inline safety wrappers, marginally reducing
the size penalty of weak functions, and works around an apparent
binutils bug that causes undefined weak symbols to not actually be
NULL when compiling with -fPIE (as EFI builds do).
A bug in versions of binutils prior to 2.16 (released in 2005) will
cause same-file weak definitions to not work with those
toolchains. Update the README to reflect our new dependency on
binutils >= 2.16.
Signed-off-by: Joshua Oreman <oremanj@rwcr.net> Signed-off-by: Michael Brown <mcb30@ipxe.org>
Dependencies are considered in left-to-right order so the source file
needs to come first in this case.
Signed-off-by: Piotr Jaroszyński <p.jaroszynski@gmail.com> Signed-off-by: Joshua Oreman <oremanj@rwcr.net> Signed-off-by: Michael Brown <mcb30@ipxe.org>
Michael Brown [Thu, 27 May 2010 08:42:53 +0000 (09:42 +0100)]
[build] Inhibit "skipping incompatible" message from ld
On 64-bit systems with both 32-bit and 64-bit libraries installed, ld
tends to generate noisy "skipping incompatible /usr/lib/libxxx.so"
messages when building elf2efi.c.
Geoff Lywood [Thu, 27 May 2010 00:04:12 +0000 (17:04 -0700)]
[efi] Verify object format support in elf2efi.c
Currently, if you attempt to build 64-bit EFI binaries on a 32-bit
system without a suitable cross-compiling version of libbfd, the iPXE
build will die with a segmentation fault in elf2efi64.
Fix by properly handling the return value from bfd_check_format().
Joshua Oreman [Tue, 25 May 2010 20:17:40 +0000 (16:17 -0400)]
[dhcp] Honor PXEBS_SKIP option in discovery control
It is permissible for a DHCP packet containing PXE options to specify
only "discovery control", instead of the more typical boot menu +
prompt options. This is the strategy used by older versions of
dnsmasq; by specifying the discovery control as PXEBS_SKIP, they cause
vendor PXE ROMs to ignore boot server discovery and just use the
filename and next-server options in the initial (Proxy)DHCP packet.
Modify iPXE to accept this behavior, to be more compatible with the
Intel firmware.
Signed-off-by: Joshua Oreman <oremanj@rwcr.net> Tested-by: Kyle Kienapfel <kyle@shadowmage.org> Modified-by: Michael Brown <mcb30@ipxe.org> Signed-off-by: Michael Brown <mcb30@ipxe.org>
Joshua Oreman [Wed, 19 May 2010 03:39:32 +0000 (23:39 -0400)]
[wpa] Remove PMKID checking
PMKID checking is an additional pre-check that helps detect invalid
passphrases before going through the full handshaking procedure. It
takes up some amount of code size, and is not necessary from a
security perspective. It also is implemented improperly by some
routers, which was causing iPXE to give spurious authentication
errors. Remove it for these reasons.
Signed-off-by: Joshua Oreman <oremanj@rwcr.net> Signed-off-by: Michael Brown <mcb30@ipxe.org>
Stefan Hajnoczi [Sat, 8 May 2010 10:49:09 +0000 (11:49 +0100)]
[comboot] Propagate carry flag from COMBOOT API
COMBOOT API calls set the carry flag on failure. This was not being
propagated because the COMBOOT interrupt handler used iret to return
with EFLAGS restored from the stack. This patch propagates CF before
returning from the interrupt.
Reported-by: Geoff Lywood <glywood@vmware.com> Signed-off-by: Stefan Hajnoczi <stefanha@gmail.com> Signed-off-by: Marty Connor <mdc@etherboot.org> Signed-off-by: Michael Brown <mcb30@ipxe.org>
Michael Brown [Fri, 21 May 2010 23:45:49 +0000 (00:45 +0100)]
[tcp] Update received sequence number before delivering received data
iPXE currently updates the TCP sequence number after delivering the
data to the application via xfer_deliver_iob(). If the application
responds to the received data by transmitting more data, this would
result in a stale ACK number appearing in the transmitted packet,
which potentially causes retransmissions and also gives the
undesirable appearance of violating causality (by sending a response
to a message that we claim not to have yet received).
Reported-by: Guo-Fu Tseng <cooldavid@cooldavid.org> Signed-off-by: Michael Brown <mcb30@ipxe.org>
Michael Brown [Fri, 21 May 2010 02:10:03 +0000 (03:10 +0100)]
[pxe] Treat PXENV_RESTART_TFTP as unreturnable
Microsoft WDS can end up calling PXENV_RESTART_TFTP to execute a
second-stage NBP which then exits. Specifically, wdsnbp.com uses
PXENV_RESTART_TFTP to execute pxeboot.com, which will exit if the user
does not press F12. iPXE currently treats PXENV_RESTART_TFTP as a
normal PXE API call, and so attempts to return to wdsnbp.com, which
has just been vaporised by pxeboot.com.
Use rmsetjmp/rmlongjmp to preserve the stack state as of the initial
NBP execution, and to restore this state immediately prior to
executing the NBP loaded via PXENV_RESTART_TFTP. This matches the
behaviour in the PXE spec (which says that "if TFTP is restarted,
control is never returned to the caller"), and allows pxeboot.com to
exit relatively cleanly back to iPXE.
As with all usage of setjmp/longjmp, there may be subtle corner case
bugs due to not gracefully unwinding any state accumulated by the time
of the longjmp call, but this seems to be the only viable way to
provide the specified behaviour.
Michael Brown [Mon, 10 May 2010 15:30:10 +0000 (16:30 +0100)]
[lacp] Add simple LACP implementation
Some switch configurations will refuse to enable our port unless we
can speak LACP to inform the switch that we are alive. Add a very
simple passive LACP implementation that is sufficient to convince at
least Linux's bonding driver (when tested using qemu attached to a tap
device enslaved to a bond device configured as "mode=802.3ad").
Signed-off-by: Piotr Jaroszyński <p.jaroszynski@gmail.com> Reviewed-by: Stefan Hajnoczi <stefanha@gmail.com> Signed-off-by: Marty Connor <mdc@etherboot.org> Signed-off-by: Michael Brown <mcb30@ipxe.org>
Michael Brown [Sun, 25 Apr 2010 14:57:00 +0000 (15:57 +0100)]
[romprefix] Add .mrom format, allowing loading of large ROMs
Add an infrastructure allowing the prefix to provide an open_payload()
method for obtaining out-of-band access to the whole iPXE image. Add
a mechanism within this infrastructure that allows raw access to the
expansion ROM BAR by temporarily borrowing an address from a suitable
memory BAR on the same PCI card.
For cards that have a memory BAR that is at least as large as their
expansion ROM BAR, this allows large iPXE ROMs to be supported even on
systems where PMM fails, or where option ROM space pressure makes it
impossible to use PMM shrinking. The BIOS sees only a stub ROM of
approximately 3kB in size; the remainder (which can be well over 64kB)
is loaded only at the time iPXE is invoked.
As a nice side-effect, an iPXE .mrom image will continue to work even
if its PMM-allocated areas are overwritten between initialisation and
invocation.
Michael Brown [Sun, 25 Apr 2010 01:54:12 +0000 (02:54 +0100)]
[build] Replace obsolete makerom.pl with quick script using Option::ROM
The only remaining useful function of makerom.pl is to correct the ROM
and PnP checksums; the PCI IDs are set at link time, and padding is
performed using padimg.pl.
Option::ROM already provides a facility for correcting the checksums,
so we may as well just use this instead.