When the 16-bit segment registers are accessed using 32-bit instructions
the high order bytes are undefined on older CPUs. We now explicitly
zero the high order bytes when snapshotting the CPU state. This ensures
that the GDB stub reports consistent values for the segment registers.
This commit implements GDB over UDP. Using UDP is more complex than
serial and has required some restructuring.
The GDB stub is now built using one or both of GDBSERIAL and GDBUDP
config.h options.
To enter the debugger, execute the gPXE shell command:
gdbstub <transport> [<options>...]
Where <transport> is "serial" or "udp". For "udp", the name of a
configured network device is required:
gdbstub udp net0
The GDB stub listens on UDP port 43770 by default.
Commit fd0aef9 introduced a typo that caused PMM detection to start at
paragraph 0xe00 rather than 0xe000. (Detection would still work, since it
would scan until it ran out of base memory, but it would end up scanning
an unnecessarily large portion of base memory.)
Spotted by Sebastian Herbszt <herbszt@gmx.de>.
Send a null command, specifically "pulse outputs" with no outputs
selected, to the KBC after changing A20. This was apparently done by DOS,
presumably as a synchronization hack, and the authors of the UHCI spec
thought it was inherent. Therefore, there are systems out there (e.g. HP
DL360 G5) which will stop responsing to "legacy USB" unless they see the
null command, 0xFF, written to port 0x64 at the end of the A20 toggling
sequence.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Some drivers that still use the legacy-driver wrapper (tg3 in particular)
apparently do not specify their alignment constraints properly. This
hack forces any __shared data to be maximally aligned.
Note that this provides only 16-byte alignment; it is not possible to
request alignment to any greater than 16 bytes using
__attribute__((aligned)), since the relocation code will preserve only 16
byte alignment (and operation under -DKEEP_IT_REAL cannot preserve more
that 16 byte alignment).
Idea proposed by Tim Hockin <thockin@google.com>
When the BIOS doesn't support BBS, hooking INT 19 is the only way to add
ourselves as a boot device. If we have to do this, we should at least
try to chain to the original INT 19 vector if our boot fails.
Idea suggested by Andrew Schran <aschran@google.com>
2.6.22+ kernels have an extra field in the bzimage_header structure to
indicate the maximum permitted command-line length. Use this if it is
available.
A bug in read_smbios_string() was causing the starting offset of the
SMBIOS structure to be added twice, resulting in completely the wrong
strings being returned.
Bug identified by Martin Herweg <m.herweg@gmx.de>
Add the definition of SLAM_MAX_BLOCKS_PER_NACK, which is roughly
equivalent to a TCP window size; it represents the maximum number of
packets that will be requested in a single NACK.
Note that, to keep the code size down, we still limit ourselves to
requesting only a single range per NACK; if the missing-block list is
discontiguous then we may request fewer than SLAM_MAX_BLOCKS_PER_NACK
blocks.
Avoid calling cpu_nap() until after we have determined that there is
no input ready to read. This avoids delaying for one timer interrupt
(~50ms) in the case of
if ( iskey() )
char = getkey()
which happens to be present in monojob.c, which is where we spend most
of our time looping (e.g. during any download).
This should eliminate the irritating tendency of gPXE to lose
keypresses.
Discovered on a Dell system where the serial port seems to send in a
constant stream of 0xff characters; this wouldn't be a problem in
itself except that each one triggers the 50ms delay (as mentioned
above), which really kills performance.
On any fast network, or with any driver that may drop packets
(e.g. Infiniband, which has very small RX rings), the traditional
usage of the SLAM protocol will result in enormous numbers of packet
drops and a consequent large number of retransmissions.
By adapting the client behaviour, we can force the server to act more
like a multicast TFTP server, with flow control provided by a single
master client.
This behaviour should interoperate with any traditional SLAM client
(e.g. Etherboot 5.4) on the network. The SLAM protocol isn't actually
documented anywhere, so it's hard to define either behaviour as
compliant or otherwise.
A missing test for dhcp->dhcpoffer in dhcp_timer_expired() was causing
the client to transition to DHCPREQUEST after timing out on waiting
for ProxyDHCP even if no DHCPOFFERs had been received.
In a SLAM NACK packet, if we run out of space to represent the
missing-block list, then indicate all remaining blocks as missing.
This avoids the need to wait for the one-second timeout before
receiving the blocks that otherwise wouldn't have been requested due
to running out of space.
Shorter NACK packets take less time to construct and spew out less
debug output, and there's a limit to how useful it is to send a
complete missing-block list anyway; if the loss rate is high then
we're going to have to retransmit an updated missing-block list
anyway.
Also add pretty debugging output to show the list of requested blocks.
We never set up specific multicast filters; native drivers will ask
the card to receive all multicast packets. The only way to achieve
this via the UNDI API is to enable promiscuous mode.
UDP sockets can be used for multicast, at which point it becomes
plausible that we could receive packets that aren't destined for us
but that still match on a port number.
Delete ELF as a generic image type. The method for invoking an
ELF-based image (as well as any tables that must be set up to allow it
to boot) will always depend on the specific architecture. core/elf.c
now only provides the elf_load() function, to avoid duplicating
functionality between ELF-based image types.
Add arch/i386/image/elfboot.c, to handle the generic case of 32-bit
x86 ELF images. We don't currently set up any multiboot tables, ELF
notes, etc. This seems to be sufficient for loading kernels generated
using both wraplinux and coreboot's mkelfImage.
Note that while Etherboot 5.4 allowed ELF images to return, we don't.
There is no callback mechanism for the loaded image to shut down gPXE,
which means that we have to shut down before invoking the image. This
means that we lose device state, protection against being trampled on,
etc. It is not safe to continue afterwards.
Revert "Use .SECONDARY instead of .PRECIOUS for bin/%.tmp targets."
This reverts commit de29e5a39c.
.SECONDARY doesn't seem to work properly with the target patterns of
implicit rules. In particular, a "make clean ; make bin/rtl8139.dsk"
will correctly leave the bin/rtl8139.dsk.tmp file present when .PRECIOUS
is used, but not when .SECONDARY is used.
This is slightly irritating since we don't want the
"do-not-delete-if-interrupted" semantics of .PRECIOUS, but it seems to be
the best compromise.
During development it is often handy to change the config.h options from
their defaults, for example to enable debugging features.
To prevent accidental commits of debugging config.h changes, mdc
suggested having a config-local.h that is excluded from source control.
This file acts as a temporary config.h and can override any of the
defaults.
This commit is an attempt to implement the config-local.h feature.
The config.h file now has the following as its last line:
/* @TRYSOURCE config-local.h */
The @TRYSOURCE directive causes config-local.h to be included at that
point in the file. If config-local.h does not exist, no error will be
printed and parsing will continue as normal. Therefore, mkconfig.pl is
"trying" to "source" config-local.h.
The GDBSYM config.h option was an attempt at QEMU GDB debugging. I have
removed the code since it is unused and may confuse people wanting to
use the GDB stub.
Maintain state for the advertised window length, and only ever increase
it (instead of calculating it afresh on each transmit). This avoids
triggering "treason uncloaked" messages on Linux peers.
Respond to zero-length TCP keepalives (i.e. empty data packets
transmitted outside the window). Even if the peer wouldn't otherwise
expect an ACK (because its packet consumed no sequence space), force an
ACK if it was outside the window.
We don't yet generate TCP keepalives. It could be done, but it's unclear
what benefit this would have. (Linux, for example, doesn't start sending
keepalives until the connection has been idle for two hours.)
When the embedded image is a script, the unregister_image() performed by
image/script.c corrupts memory, since image/embedded.c omitted the call
to register_image().
This is the first bug fixed using Stefan Hajnoczi's gdb stub for gPXE.
Return the most appropriate of EACCES, EPERM, ENODEV, ENOTSUP, EIO or
EINVAL depending on the exact error returned by the target, rather than
just always returning EPERM.
Also, ensure that error strings exist for these errors.
The ROM prefix now prompts the user to enter the gPXE shell during POST;
this allows for configuring gPXE without needing to attempt to boot from
it. (It also slows down system boot by three seconds per gPXE ROM, but
hey.)
This is apparently a certain OEM's requirement for option ROMs.
Various specification documents disagree about the byte ordering of
UUIDs. However, SMBIOS seems to use the standard in which everything is
in network-endian order.
This doesn't affect anything sent on the wire; only what gets printed on
the screen when the "uuid" variable is displayed.
From: Daniel Mealha Cabrita <dancab@utfpr.edu.br>
I've added tg3-5721 support for gPXE, the patch (against gpxe-0.9.3) is
attached to this message.
This chipset is present in HP ML150 G2 servers (possibly other HP machines
as well).
From: Viswanath Krishnamurthy <viswa.krish@gmail.com>
The current ipv4 incorrectly checks the IP address for multicast address.
This causes valid IPv4 unicast address to be trated as multicast address
For e.g if the PXE/tftp server IP address is 192.168.4.XXX where XXX is
224 or greater, it gets treated as multicast address and a ethernet
multicast address is sent out on the wire causing timeouts
Some EMC targets will fail if we advertise that we can authenticate with
CHAP, but the target is configured to allow unauthenticated access to that
target. We advertise AuthMethod=CHAP,None; the target should (I think)
select AuthMethod=None for unprotected targets. IETD does this, but an
EMC Celerra NS83 doesn't.
Fix by offering only AuthMethod=None if the user hasn't supplied a
username and password; this means that we won't be offering CHAP
authentication unless the user is expecting to use it (in which case the
target is presumably configured appropriately).
Many thanks to Alessandro Iurlano <alessandro.iurlano@gmail.com> for
reporting and helping to diagnose this problem.
ROMs will refuse to build unless pci_vendor_id and pci_device_id are
defined. We probably ought to fix up the Makefile (and the ROM prefix) so
that they're required only for PCI ROMs, but this will do for now.
Drivers are not allowed to call printf(). Converted eprintf() to DBG(),
and removed spurious startup banner.
Fixed hardcoded inclusion of little_bswap.h
Use EIO rather than 1 as an error number.
Add ability for network devices to flag link up/down state to the
networking core.
Autobooting code will now wait for link-up before attempting DHCP.
IPoIB reflects the Infiniband link state as the network device link state
(which is not strictly correct; we also need a succesful IPoIB IPv4
broadcast group join), but is probably more informative.
Infiniband devices no longer block waiting for link-up in
register_ibdev().
Hermon driver needs to create an event queue and poll for link-up events.
Infiniband core needs to reread MAD parameters when link state changes.
IPoIB needs to cope with Infiniband link parameters being only partially
available at probe and open time.
PXE is a catch-all image format with no signature checks. If an
unsupported image file is loaded, it will be treated as a PXE image. In
most cases, the image will be too large to be loaded as a PXE image (which
has to fit in base memory), so the error returned to the user will be that
the segment could not fit within the memory region.
Add an explicit check to pxe_image.c to reject images larger than base
memory with ENOEXEC.
Add ENOEXEC to the error string table.
gPXE is not compliant with the HTTP/1.1 specification (RFC 2616),
since it lacks support for "Transfer-Encoding: chunked". gPXE is,
however, compliant with the HTTP/1.0 specification (RFC 1945), which
does not require "Transfer-Encoding: chunked" to be supported.
The only HTTP/1.1 feature that gPXE uses is the "Host:" header, but
servers universally accept that one from HTTP/1.0 clients as an
optional extension (it is obligatory for HTTP/1.1). gPXE does not,
for example, appear to support connection caching. Advertising as a
HTTP/1.0 client will typically make the server close the connection
immediately upon sending the last data, which is actually beneficial
if we aren't going to keep the connection alive anyway.
The PXE spec is (as usual) unclear on precisely when ProxyDHCPREQUESTs
should be issued. We adapt the following, slightly paranoid approach:
If an offer contains an IP address, then it is a normal DHCPOFFER.
If an offer contains an option #60 "PXEClient", then it is a
ProxyDHCPOFFER. Note that the same packet can be both a normal
DHCPOFFER and a ProxyDHCPOFFER.
After receiving the normal DHCPACK, if we have received a
ProxyDHCPOFFER, we unicast a ProxyDHCPREQUEST back to the ProxyDHCP
server on port 4011. If we time out waiting for a ProxyDHCPACK, we
treat this as a non-fatal error.
Change the PXE return code for EWOULDBLOCK from PXENV_STATUS_FAILURE
to PXENV_STATUS_TFTP_OPEN. This code is only used by the FILE_READ
PXEXT call, and is necessary to distinguish "error" from "no data" in
that call.
(The only other nonblocking call is UDP_READ, where the caller doesn't
care about the distinction, however, gPXE doesn't use EWOULDBLOCK
internally to represent this condition in that code.)
Allow for settings to be described by something other than a DHCP option
tag if desirable. Currently used only for the MAC address setting.
Separate out fake DHCP packet creation code from dhcp.c to fakedhcp.c.
Remove notion of settings from dhcppkt.c.
Rationalise dhcp.c to use settings API only for final registration of the
DHCP options, rather than using {store,fetch}_setting throughout.
Add dedicated functions create_dhcpdiscover(), create_dhcpack() and
create_proxydhcpack() for use by external code such as the PXE preboot
code.
Register ProxyDHCP options under the global scope "proxydhcp".
Unregister previously-acquired DHCP and ProxyDHCP settings when DHCP
succeeds.
Stefan Hajnoczi