When making a call from real mode to protected mode, we save and
restore the global and interrupt descriptor table registers. The
restore currently takes place after returning to real mode, which
generates two EXCEPTION_NMIs and corresponding VM exits when running
under KVM on an Intel CPU.
Avoid the VM exits by restoring the descriptor table registers inside
prot_to_real, while still running in protected mode.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Ensure that all segment registers have zero in the low two bits before
transitioning to protected mode. This allows the CPU state to
immediately be deemed to be "valid", and eliminates the need for any
further emulated instructions.
Load the protected-mode interrupt descriptor table after switching to
protected mode, since this avoids triggering an EXCEPTION_NMI and
corresponding VM exit.
This reduces the time taken by real_to_prot under KVM by around 50%.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
On an Intel CPU supporting VMX, KVM will emulate instructions while
the CPU state remains "invalid". In real mode, the CPU state is
defined to be "invalid" if any segment register has a base which is
not equal to (sreg<<4) or a limit which is not equal to 64kB.
We don't actually use the base stored in the REAL_DS descriptor for
any significant purpose. Change the base stored in this descriptor to
be equal to (REAL_DS<<4). A segment register loaded with REAL_DS is
then automatically valid in both real and protected modes. This
allows KVM to stop emulating instructions much sooner.
The only use of REAL_DS for memory accesses currently occurs in the
indirect ljmp within prot_to_real. Change this to a direct ljmp,
storing rm_cs in .text16 as part of the ljmp instruction. This
removes the only memory access via REAL_DS (thereby allowing for the
above descriptor base address hack), and also simplifies the ljmp
instruction (which will still have to be emulated).
Load the real-mode interrupt descriptor table register before
switching to real mode, since this avoids triggering an EXCEPTION_NMI
and corresponding VM exit.
This reduces the time taken by prot_to_real under KVM by around 65%.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The mode-transition code involves paths which switch back and forth
between the .text and .text16 sections. At present, only the start of
each function is labelled, which makes it difficult to decode
addresses within the parts of the function existing in a different
section.
Add explicit labels at the start of each section change, so that
addresses can be meaningfully decoded to the nearest label.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Now that we can handle interrupts while in protected mode, there is no
need to switch to real mode just to halt the CPU.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The currticks() function is called at least once per TCP packet, and
so is performance-critical. Switching to real mode just to allow the
timer interrupt to fire is expensive when running inside a virtual
machine, and imposes a significant performance cost.
Fix by enabling interrupts without switching to real mode. This
results in an approximately 100% increase in download speed when
running under KVM.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
We now have the ability to handle interrupts while in protected mode,
and so no longer need to set up a dedicated interrupt descriptor table
while running COM32 executables.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
When running in a virtual machine, switching to real mode may be
expensive. Allow interrupts to be enabled while in protected mode and
reflected down to the real-mode interrupt handlers.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
We currently use flat real mode wherever real mode is required. This
guarantees that we will not surprise some unsuspecting external caller
which has carefully set up flat real mode by suddenly reducing the
segment limits to 64kB.
However, operating in flat real mode imposes a severe performance
penalty in some virtualisation environments, since some CPUs cannot
fully virtualise flat real mode and so the hypervisor must fall back
to emulation. In particular, operating under KVM on a pre-Westmere
Intel CPU will be at least an order of magnitude slower, to the point
that there is a visible teletype effect when printing anything to the
BIOS console. (Older versions of KVM used to cheat and ignore the
"flat" part of flat real mode, which masked the problem.)
Switch (back) to using genuine real mode with 64kB segment limits
instead of flat real mode. Hopefully this won't break anything.
Add an explicit switch to flat real mode before returning to the BIOS
from the ROM prefix, since we know that a PMM BIOS will call the ROM
initialisation point (and potentially the BEV) in flat real mode.
As noted in previous commit messages, it is not possible to restore
the real-mode segment limits after a transition to protected mode,
since there is no way to know which protected-mode segment descriptor
was originally used to initialise the limit portion of the segment
register.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
We observed some time ago (in commit 4ce8d61 "Import various libgcc
functions from syslinux") that gcc seems to treat calls to the
implicit arithmetic functions (e.g. __udivdi3()) as being affected by
-mregparm but unaffected by -mrtd.
This seems to be no longer the case with current gcc versions, which
treat calls to these functions as being affected by both -mregparm and
-mrtd, as expected.
There is nothing obvious in the gcc changelogs to indicate precisely
when this happened. From experimentation with available gcc versions,
the change occurred sometime between v4.6.3 and v4.7.2. We assume
that only versions up to v4.6.x require the special treatment.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Some BIOSes (observed with a ProLiant DL360p Gen8 SE) perform no range
checking whatsoever on the parameters passed to INT10,06 and will
therefore happily write to an area beyond the end of video RAM. The
area immediately following the video RAM tends to be the VGA BIOS ROM
image. Overwriting the VGA BIOS leads to an interesting variety of
crashes and reboots.
Fix by specifying an exact width and height to be cleared, rather than
passing in large values and relying upon the BIOS to truncate them to
the appropriate range.
Reported-by: Alex Davies <adavies@jumptrading.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Some UEFI builds will set up a timer to continuously poll any SNP
devices. This can drain packets from the network device's receive
queue before iPXE gets a chance to process them.
Use netdev_rx_[un]freeze() to explicitly indicate when we expect our
network devices to be driven via the external SNP API (as we do with
the UNDI API on the standard BIOS build), and disable the SNP API
except when receive queue processing is frozen.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
EFIRC() uses PLATFORM_TO_ERRNO(), which evaluates its argument twice
(and can't trivially use a braced-group expression or an inline
function to avoid this, since it gets used outside of function
context).
The expression "EFIRC(main())" will therefore end up calling main()
twice, which is not the intended behaviour. Every other instance of
EFIRC() is of the simple form "EFIRC(rc)", so fix by converting this
instance to match.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
iPXE will detect timeout failures in several situations: network
link-up, DHCP, TCP connection attempts, unacknowledged TCP data, etc.
This does not cover all possible circumstances. For example, if a
connection to a web server is successfully established and the web
server acknowledges the HTTP request but never sends any data in
response, then no timeout will be triggered. There is no timeout
defined within the HTTP specifications, and the underlying TCP
connection will not generate a timeout since it has no way to know
that the HTTP layer is expecting to receive data from the server.
Add a "--timeout" parameter to "imgfetch", "chain", etc. If no
progress is made (i.e. no data is downloaded) within the timeout
period, then the download will be aborted.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Commit c429bf0 ("[romprefix] Store boot bus:dev.fn address as autoboot
device location") introduced a regression by using register %cx to
temporarily hold the PCI bus:dev.fn address, despite the fact that %cx
was already being used to hold the stored BIOS stack segment.
Consequently, when returning to the BIOS after a failed or cancelled
boot attempt, iPXE would end up calling INT 18 with the stack segment
set equal to the PCI bus:dev.fn address. Writing to essentially
random areas of memory tends to upset even the more robust BIOSes.
Fix by using register %ax to temporarily hold the PCI bus:dev.fn
address.
Reported-by: Anton D. Kachalov <mouse@yandex-team.ru>
Tested-by: Anton D. Kachalov <mouse@yandex-team.ru>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
iPXE currently pads initrd images to a multiple of 4kB and inserts
zero padding between images, as required by some versions of the Linux
kernel. The overall length reported via the ramdisk_size field in the
bzImage header includes this zero padding.
This causes problems when using memdisk to load a gzip-compressed disk
image. memdisk treats the ramdisk_size field as containing the exact
length of the initrd image, and uses this length to locate the 8-byte
gzip footer. This will generally cause memdisk to fail to decompress
the disk image.
Fix by reporting the exact length of the initrd image set, including
any padding inserted between images but excluding any padding added at
the end of the final image.
Reported-by: Levente LEVAI <levail@aviatronic.hu>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
qemu can load an option ROM which is not associated with a particular
PCI device using the "-option-rom" syntax. Under these circumstances,
we should ignore the PCI bus:dev.fn address that we expect to find in
%ax on entry to the initialisation vector.
Fix by using the PCI bus:dev.fn address only if it is non-zero. Since
00:00.0 will always be the host bridge, it can never be the address of
a network card.
Reported-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Per the BIOS Boot Specification, the initialization phase of the ROM
is called with the PFA (PCI Function Address) in the %ax register.
The intention is that the ROM code will store that device address
somewhere and use it for booting from that device when the Boot Entry
Vector (BEV) is called. iPXE does store the PFA, but doesn't use it
to select the boot network device. This renders BIOS IPL lists fairly
ineffective.
Fix by using the BBS-specified bus:dev.fn address as the autoboot
device location.
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Modified-by: Michael Brown <mcb30@ipxe.org>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
iPXE currently prints a "Press Ctrl-B" banner twice: once when the ROM
is first called for initialisation and again if we attempt to boot
from the ROM. This slows boot, especially when the NIC is not the
primary boot device. Tools such as libguestfs make use of QEMU VMs
for performing maintenance on disk images and may make use of NICs in
the VM for network support. If iPXE introduces a static init-time
delay, that directly translates to increased runtime for the tools.
Fix by allowing the ROM banner timeout to be configured independently
of the main banner timeout.
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Modified-by: Michael Brown <mcb30@ipxe.org>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Add support for parsing of URIs containing literal IPv6 addresses
(e.g. "http://[fe80::69ff:fe50:5845%25net0]/boot.ipxe").
Duplicate URIs by directly copying the relevant fields, rather than by
formatting and reparsing a URI string. This relaxes the requirements
on the URI formatting code and allows it to focus on generating
human-readable URIs (e.g. by not escaping ':' characters within
literal IPv6 addresses). As a side-effect, this allows relative URIs
containing parameter lists (e.g. "../boot.php##params") to function
as expected.
Add validity check for FTP paths to ensure that only printable
characters are accepted (since FTP is a human-readable line-based
protocol with no support for character escaping).
Construct TFTP next-server+filename URIs directly, rather than parsing
a constructed "tftp://..." string,
Add self-tests for URI functions.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Rename the "--bpp" option to "--depth", to free up the single-letter
option "-b" for "--bottom" in preparation for adding margin support.
This does not break backwards compatibility with documented features,
since the "console" command has not yet been documented.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Allow for an arbitrary margin to be specified in the console
configuration. If the actual screen size does not match the requested
screen size, then update any margins specified so that they remain in
the same place relative to the requested screen size. If margins are
unspecified (i.e. zero), then leave them as zero.
The underlying assumption here is that any specified margins are
likely to describe an area within a background picture, and so should
remain in the same place relative to that background picture.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Use the magic colour facility to cause the user interface background
to become transparent when we have a background picture.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The vgabios used by bochs and qemu (and other virtualisation products)
has a bug in its implementation of INT 10,4f00 which causes the high
16 bits of %ebx and %edx to become corrupted.
The vgabios code uses a "pushaw"/"popaw" pair to preserve the low 16
bits of all non-segment registers. The vgabios code is compiled using
bcc, which generates 8086-compatible code and so never touches the
high 16 bits of the 32-bit registers. However, the function
vbe_biosfn_return_controller_information() includes the line:
size_64k = (Bit16u)((Bit32u)cur_info->info.XResolution *
cur_info->info.XResolution *
cur_info->info.BitsPerPixel) >> 19;
which generates an implicit call to the "lmulul" function. This
function is implemented in vbe.c as:
; helper function for memory size calculation
lmulul:
and eax, #0x0000FFFF
shl ebx, #16
or eax, ebx
SEG SS
mul eax, dword ptr [di]
mov ebx, eax
shr ebx, #16
ret
which modifies %eax, %ebx, and %edx (as a result of the "mul"
instruction, which places its result into %edx:%eax).
Work around this problem by marking %ebx and %edx as being clobbered
by the call to INT 10,4f00. (%eax is already used as an output
register, so does not need to be on the clobber list.)
Reported-by: Oliver Rath <rath@mglug.de>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The fetch_setting() family of functions may currently modify the
definition of the specified setting (e.g. to add missing type
information). Clean up this interface by requiring callers to provide
an explicit buffer to contain the completed definition of the fetched
setting, if required.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
There is no requirement for VBE modes to be listed in increasing order
of resolution. With the present logic, this can cause e.g. a 1024x768
mode to be selected if the user asks for 640x480, if the 1024x768 mode
is earlier in the mode list.
Define a scoring system for modes as
score = ( width * height - bpp )
and choose the mode with the lowest score among all acceptable modes.
This should prefer to choose the mode closest to the requested
resolution, with a slight preference for higher colour depths.
Reported-by: Robin Smidsrød <robin@smidsrod.no>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The VirtualBox BIOS fails to retrieve mode information (with status
0x0100) for some modes within the mode list. Skip any such modes,
rather than treating this as a fatal error.
Reported-by: Robin Smidsrød <robin@smidsrod.no>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The VESA frame buffer console uses the VESA BIOS extensions (VBE) to
enumerate video modes, selects an appropriate mode, and then hands off
to the generic frame buffer code.
The font is extracted from the VGA BIOS, avoiding the need to provide
an external font file.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Syslinux 6.x places its files into a bios subdirectory, and requires
that a ldlinux.c32 module be included within the ISO image. Add the
relevant search paths for isolinux.bin, and include the file
ldlinux.c32 within the ISO image if it exists.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The retrieval of the cached DHCPACK and the creation of network
devices are both currently scheduled as STARTUP_NORMAL. It is
therefore possible that the cached DHCPACK will not be retrieved in
time for cachedhcp_probe() to apply it to the relevant network device.
Fix by retrieving the cached DHCPACK at initialisation time rather
than at startup time.
As an optimisation, an unclaimed cached DHCPACK can be freed
immediately after the last network device has been created, rather
than waiting until shutdown.
Reported-by: Espen Braastad <espen.braastad@redpill-linpro.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Most network upper-layer drivers do not implement all three methods
(probe, notify, and remove). Save code by making all methods
optional.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
When chainloading, always retrieve the cached DHCPACK packet from the
underlying PXE stack, and apply it as the original contents of the
"net<X>.dhcp" settings block. This allows cached DHCP settings to be
used for any chainloaded iPXE binary (not just undionly.kkpxe).
This change eliminates the undocumented "use-cached" setting. Issuing
the "dhcp" command will now always result in a fresh DHCP request.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Commit 238050d ("[build] Work around bug in gcc >= 4.8") works around
one instance of a bug in recent versions of gcc, in which "ebp" cannot
be specified within an asm clobber list.
Some versions of gcc seem to exhibit the same bug on other points in
the codebase. Fix by changing all instances of "ebp" in a clobber
list to use the push/pop %ebp workaround instead.
Originally-implemented-by: Víctor Román Archidona <contacto@victor-roman.es>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Allow CPUID values to be read using the syntax
${cpuid/<register>.<function>}
For example, ${cpuid/2.0x80000001} will give the value of %ecx after
calling CPUID with %eax=0x80000001. Values for <register> are encoded
as %eax=0, %ebx=1, %ecx=2, %edx=3.
The numeric encoding is more sophisticated than described above,
allowing for settings such as the CPU model (obtained by calling CPUID
with %eax=0x80000002-0x80000004 inclusive and concatenating the values
returned in %eax:%ebx:%ecx:%edx). See the source code for details.
The "cpuvendor" and "cpumodel" settings provide easy access to these
more complex CPUID settings.
This functionality is intended to complement the "cpuid" command,
which allows for testing individual CPUID feature bits.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
There are currently two conflicting usages of the term "named setting"
within iPXE: one refers to predefined settings (such as show up in the
"config" UI), the other refers to settings identified by a name (such
as "net0.dhcp/ip").
Split these usages into the term "predefined setting" and "named
setting" to avoid ambiguity.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Our use of --gc-sections causes the linker to discard the symbols
defined by FILE_LICENCE(), meaning that the resulting licence
determination is incomplete.
We must use the KEEP() directive in the linker script to force the
linker to not discard the licence symbols. Using KEEP(*(COMMON))
would be undesirable, since there are some symbols in COMMON which we
may wish to discard.
Fix by placing symbols defined by PROVIDE_SYMBOL() (which is used by
FILE_LICENCE()) into a special ".provided" section, which we then mark
with KEEP(). All such symbols are zero-length, so there is no cost in
terms of the final binary size.
Since the symbols are no longer in COMMON, the linker will reject
symbols with the same name coming from multiple objects. We therefore
append the object name to the licence symbol, to ensure that it is
unique.
Reported-by: Marin Hannache <git@mareo.fr>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
gcc 4.8 and 4.9 fail to compile pxe_call.c with the error "bp cannot
be used in asm here". Other points in the codebase which use "ebp" in
the asm clobber list do not seem to be affected.
Unfortunately gcc provides no way to specify %ebp as an output
register, so we cannot use this as a workaround. The only viable
solution is to explicitly push/pop %ebp within the asm itself. This
is ugly for two reasons: firstly, it may be unnecessary; secondly, it
may cause gcc to generate invalid %esp-relative addresses if the asm
happens to use memory operands. This specific block of asm uses no
memory operands and so will not generate invalid code.
Reported-by: Daniel P. Berrange <berrange@redhat.com>
Reported-by: Christian Hesse <list@eworm.de>
Originally-fixed-by: Christian Hesse <list@eworm.de>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Some versions of Linux apparently complain if initrds are not aligned
to a page boundary. Fix by changing INITRD_ALIGN from 4 bytes to 4096
bytes.
The amount of padding at the end of each initrd will now often be
sufficient to allow the cpio header to be prepended without crossing
an alignment boundary. The final location of the initrd may therefore
end up being slightly higher than the post-shuffle location.
bzimage_load_initrd() must therefore now copy the initrd body prior to
copying the cpio header, otherwise the start of the initrd body may be
overwritten by the cpio header. (Note that the guarantee that an
initrd will never need to overwrite an initrd at a higher location
still holds, since the overall length of each initrd cannot decrease
as a result of adding a cpio header.)
Reported-by: Dave Hansen <dave@sr71.net>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Commit 2422647 ("[prefix] Allow prefix to specify an arbitrary maximum
address for relocation") introduced a regression into the UNDI ROM
loader by preserving an extra register on the stack without modifying
the %sp-relative addresses used in the routine.
Fix by correcting the %sp-relative addresses to allow for the extra
preserved variable.
Signed-off-by: Frediano Ziglio <frediano.ziglio@citrix.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
When the $(eval) function is available (in GNU make >= 3.80), we can
evaluate many of the dynamically-generated Makefile rules directly.
This avoids generating a few hundred Makefile fragments in the
filesystem, and so speeds up the build process.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Create an explicit concept of "settings scope" and eliminate the magic
values used for numerical setting tags.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Report the cause of the failure when we are unable to open the .mrom
payload. There are two possible failure cases:
- Unable to find a suitable memory BAR to borrow (e.g. if the NIC
doesn't have a memory BAR that is at least as large as the
expansion ROM BAR, or if the memory BAR has been assigned a 64-bit
address which won't fit into the 32-bit expansion ROM BAR). This
will be reported as "BABABABA".
- Unable to find correct ROM image within the BAR. This will be
reported as the address (within the borrowed BAR) at which we first
fail to find a valid 55AA signature.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Exploit the redefinition of iPXE error codes to include a "platform
error code" to allow for meaningful conversion of EFI_STATUS values to
iPXE errors and vice versa.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The low 8 bits of an iPXE error code are currently defined as the
closest equivalent PXE error code. Generalise this scheme to
platforms other than PC-BIOS by extending this definition to "closest
equivalent platform error code". This allows for the possibility of
returning meaningful errors via EFI APIs.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The implementation of INT 10,06 on some BIOSes (observed with both
Hyper-V and a Dell OptiPlex 7010) seems to treat %dx=0xffff as a
special value meaning "do absolutely nothing". Fix by using
%dx=0xfefe, which should still be sufficient to cover any realistic
screen size.
Reported-by: John Clark <skyman@iastate.edu>
Tested-by: John Clark <skyman@iastate.edu>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Abstract out the ability to reboot the system to a separate reboot()
function (with platform-specific implementations), add an EFI
implementation, and make the existing "reboot" command available under
EFI.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Commit 2629b7e ("[pcbios] Inhibit all calls to INT 15,e820 and INT
15,e801 during POST") introduced a regression into .lkrn images when
used with no corresponding initrd.
Specifically, the semantics of the "maximum address for relocation"
value passed to install_prealloc() in %ebp changed so that zero became
a special value meaning "inhibit use of INT 15,e820 and INT 15,e801".
The %ebp value meaing "no upper limit on relocation" was changed from
zero to 0xffffffff, and all prefixes providing fixed values for %ebp
were updated to match the new semantics.
The .lkrn prefix provides the initrd base address as the maximum
address for relocation. When no initrd is present, this address will
be zero, and so will unintentionally trigger the "inhibit INT 15,e820
and INT 15,e801" behaviour.
Fix by explicitly setting %ebp to 0xffffffff if no initrd is present
before calling install_prealloc().
Reported-by: Ján ONDREJ (SAL) <ondrejj@salstar.sk>
Tested-by: Ján ONDREJ (SAL) <ondrejj@salstar.sk>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
If a multifunction PCI device exposes an iPXE ROM via each function,
then each function will display a "Press Ctrl-B to configure iPXE"
prompt, and delay for two seconds. Since a single instance of iPXE
can drive all functions on the multifunction device, this simply adds
unnecessary delay to the boot process.
Fix by inhibiting the "Press Ctrl-B" prompt for all except the first
function on a PCI device.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Many BIOSes do not construct the full system memory map until after
calling the option ROM initialisation entry points. For several
years, we have added sanity checks and workarounds to accommodate
charming quirks such as BIOSes which report the entire 32-bit address
space (including all memory-mapped PCI BARs) as being usable RAM.
The IBM x3650 takes quirky behaviour to a new extreme. Calling either
INT 15,e820 or INT 15,e801 during POST doesn't just get you invalid
data. We could cope with invalid data. Instead, these nominally
read-only API calls manage to trash some internal BIOS state, with the
result that the system memory map is _never_ constructed. This tends
to confuse subsequent bootloaders and operating systems.
[ GRUB 0.97 fails in a particularly amusing way. Someone thought it
would be a good idea for memcpy() to check that the destination memory
region is a valid part of the system memory map; if not, then memcpy()
will sulk, fail, and return NULL. This breaks pretty much every use
of memcpy() including, for example, those inserted implicitly by gcc
to copy non-const initialisers. Debugging is _fun_ when a simple call
to printf() manages to create an infinite recursion, exhaust the
available stack space, and shut down the CPU. ]
Fix by completely inhibiting calls to INT 15,e820 and INT 15,e801
during POST.
We do now allow relocation during POST up to the maximum address
returned by INT 15,88 (which seems so far to always be safe). This
allows us to continue to have a reasonable size of external heap, even
if the PMM allocation is close to the 1MB mark.
The downside of allowing relocation during POST is that we may
overwrite PMM-allocated memory in use by other option ROMs. However,
the downside of inhibiting relocation, when combined with also
inhibiting calls to INT 15,e820 and INT 15,e801, would be that we
might have no external heap available: this would make booting an OS
impossible and could prevent some devices from even completing
initialisation.
On balance, the lesser evil is probably to allow relocation during
POST (up to the limit provided by INT 15,88). Entering iPXE during
POST is a rare operation; on the even rarer systems where doing so
happens to overwrite a PMM-allocated region, then there exists a
fairly simple workaround: if the user enters iPXE during POST and
wishes to exit iPXE, then the user must reboot. This is an acceptable
cost, given the rarity of the situation and the simplicity of the
workaround.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
romprefix.S currently calls uninstall() with an invalid value in %ax.
Consequently, base memory is not freed after a ROM boot attempt (or
after entering iPXE during POST).
The uninstall() function is physically present in .text16, and so can
use %cs to determine the .text16 segment address. The .data16 segment
address is not required, since uninstall() is called only by code
paths which set up .data16 to immediately follow .text16.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The PXE TFTP API allows the caller to request a particular TFTP block
size. Since mid-2008, iPXE has appended a "?blksize=xxx" parameter to
the TFTP URI constructed internally; nothing has ever parsed this
parameter. Nobody seems to have cared that this parameter has been
ignored for almost five years.
Fix by using xfer_window(), which provides a fairly natural way to
convey the block size information from the PXE TFTP API to the TFTP
protocol layer.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Some PXE stacks are known to claim that IRQs are supported, but then
never generate interrupts. No satisfactory solution has been found to
this problem; the workaround is to add the PCI vendor and device IDs
to a list of devices which will be treated as simply not supporting
interrupts.
This is something of a hack, since it will generate false positives
for identical devices with a working PXE stack (e.g. those that have
been reflashed with iPXE), but it's an improvement on the current
situation.
Reported-by: Richard Moore <rich@richud.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
At present, loading a bzImage via iPXE requires enough RAM to hold two
copies of each initrd file. Remove this constraint by rearranging the
initrds in place.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
No code from the original source remains within this file; relicense
under GPL2+ with a new copyright notice.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Current versions of gcc require -maccumulate-outgoing-args if any
sysv_abi functions call ms_abi functions. This requirement is likely
to be lifted in future gcc versions, so test explicitly to see if the
current version of gcc requires -maccumulate-outgoing-args.
This problem is currently masked since the implied
-fasynchronous-unwind-tables (which is the default in current gcc
versions) implies -maccumulate-outgoing-args.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Commit 73eb3f1 ("[int13] Zero all possible registers when jumping to a
boot sector") introduced a regression preventing the SAN-booting of
boot sectors which rely upon %dl containing the correct drive number
(such as most CD-ROM boot sectors).
Fix by not zeroing %edx.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
At least one boot sector (the DUET boot sector used for bootstrapping
EFI from a non-EFI system) fails to initialise the high words of
registers before using them in calculations, leading to undefined
behaviour.
Work around such broken boot sectors by explicitly zeroing the
contents of all registers apart from %cs:%ip and %ss:%sp.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Almost all clients of the raw-packet interfaces (UNDI and SNP) can
handle only Ethernet link layers. Expose an Ethernet-compatible link
layer to local clients, while remaining compatible with IPoIB on the
wire. This requires manipulation of ARP (but not DHCP) packets within
the IPoIB driver.
This is ugly, but it's the only viable way to allow IPoIB devices to
be driven via the raw-packet interfaces.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
COMBOOT images are detected by looking for a ".com" or ".cbt" filename
extension. There are widely-used files with a ".com" extension, such
as "wdsnbp.com", which are PXE images rather than COMBOOT images.
Avoid false detection of PXE images as COMBOOT images by accepting
only a ".cbt" extension as indicating a COMBOOT image.
Interestingly, this bug has been present for a long time but was
frequently concealed because the filename was truncated to fit the
fixed-length "name" field in struct image. (PXE binaries ending in
".com" tend to be related to Windows deployment products and so often
use pathnames including backslashes, which iPXE doesn't recognise as a
path separator and so treats as part of a very long filename.)
Commit 1c127a6 ("[image] Simplify image management commands and
internal API") made the image name a variable-length field, and so
exposed this flaw in the COMBOOT image detection algorithm.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Allow the file mode to be specified using a "mode=" command line
parameter. For example:
initrd http://web/boot/bootlocal.sh /opt/bootlocal.sh mode=755
Requested-by: Bryce Zimmerman <bryce.zimmerman@gmail.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Some AMI BIOSes apparently break in exciting ways when asked for PMM
allocations for sizes that are not multiples of 4kB.
Fix by rounding up the image source area to the nearest 4kB. (The
temporary decompression area is already rounded up to the nearest
128kB, to facilitate sharing between multiple iPXE ROMs.)
Reported-by: Itay Gazit <itayg@mellanox.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Cygwin's assembler treats '/' as a comment character.
Reported-by: Steve Goodrich <steve.goodrich@se-eng.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Similarly to FreeBSD, OpenBSD requires the object format to be
specified as elf_i386_obsd rather than elf_i386.
Reported-by: Jiri B <jirib@devio.us>
Modified-by: Michael Brown <mcb30@ipxe.org>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
PCI3.0 allows us to report a "runtime size" which can be smaller than
the actual ROM size. On systems that support PMM our runtime size
will be small (~2.5kB), which helps to conserve the limited option ROM
space. However, there is no guarantee that the PMM allocation will
succeed, and so we need to report the worst-case runtime size in the
PCI header.
Move the "shrunk ROM size" field from the PCI header to a new "iPXE
ROM header", allowing it to be accessed by ROM-manipulation utilities
such as disrom.pl.
Reported-by: Anton D. Kachalov <mouse@yandex-team.ru>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
PXENV_FILE_CMDLINE is an iPXE extension, and will not be supported by
most PXE stacks. Do not report any errors to the user, since in
almost all cases the error will mean simply "not loaded by iPXE".
Reported-by: Patrick Domack <patrickdk@patrickdk.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Attempt to restore the network device to the state it was in prior to
calling the NBP. This simplifies the task of taking follow-up action
in an iPXE script.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Some BIOSes (observed on a Supermicro system with an AMI BIOS) seem to
use the area immediately below 0x7c00 to store data related to the
boot process. This data is currently liable to be overwritten by the
temporary stack used while decompressing and installing iPXE.
Try to avoid any such problems by placing the temporary stack
immediately after the loaded iPXE binary. Any memory used by the
stack could then potentially have been overwritten anyway by a larger
binary.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The setup_move_size field is not defined in protocol versions earlier
than 2.00 (and is obsolete in versions later than 2.01). In binaries
using versions earlier than 2.00, the relevant location is likely to
contain executable code.
Interestingly, this bug has been present since support for pre-2.00
protocol versions was added in 2009, and has been unexpectedly
modifying the memtest86+ code fragment:
mov $0x92, %dx
inb %dx, %al
Fortuitously, the modification exactly overwrote the value loaded into
%dx, and so the net effect was limited to causing Fast Gate A20
detection to always fail.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The undinet driver always has to make a copy of the received frame
into an I/O buffer. Align this copy sensibly so that subsequent
operations are as fast as possible.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The generic TCP/IP checksum implementation requires approximately 10
CPU clocks per byte (as measured using the TSC). Improve this to
approximately 0.5 CPU clocks per byte by using "lodsl ; adcl" in an
unrolled loop.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Calculating the TCP/IP checksum on received packets accounts for a
substantial fraction of the response latency.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The "rep" prefix can be used with an iteration count of zero, which
allows the variable-length memcpy() to be implemented without using
any conditional jumps.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
PMM defines the return code 0xffffffff as meaning "unsupported
function". It's hard to imagine a PMM BIOS that doesn't support
pmmAllocate(), but apparently such things do exist.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
A .mrom image currently assumes that it is the first image within the
expansion ROM BAR, which may not be correct when multiple images are
present.
Fix by scanning through the BAR until we locate an image matching our
build ID.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The header of a .mrom image declares its length to be only a few
kilobytes; the remainder is accessed via a sideband mechanism. This
makes it difficult to append an additional ROM image, such as an EFI
ROM.
Add a second, dummy ROM header covering the payload portion of the
.mrom image, allowing consumers to locate any appended ROM images in
the usual way.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Avoid potential confusion in the documentation by using a
vendor-neutral name for the extended (AMD-defined) feature set.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The WinCE, a.out and FreeBSD loaders are designed to be #included by
core/loader.c, which no longer exists. These old loaders are not
usable anymore and cause compilation failures when enabled in
config/general.h.
Signed-off-by: Marin Hannache <mareo@mareo.fr>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Solaris assumes that there is enough space above the Multiboot modules
to use as a decompression and scratch area. This assumption is
invalid when using iPXE, which places the Multiboot modules near the
top of (32-bit) memory.
Fix by copying the modules to an area of memory immediately following
the loaded kernel.
Debugged-by: Michael Brown <mcb30@ipxe.org>
Debugged-by: Scott McWhirter <scottm@joyent.com>
Tested-by: Robin Smidsrød <robin@smidsrod.no>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Allow iPXE settings to be specified in the .vmx file via the VMware
GuestInfo mechanism. For example:
guestinfo.ipxe.filename = "http://boot.ipxe.org/demo/boot.php"
guestinfo.ipxe.dns = "192.168.0.1"
guestinfo.ipxe.net0.ip = "192.168.0.15"
guestinfo.ipxe.net0.netmask = "255.255.255.0"
guestinfo.ipxe.net0.gateway = "192.168.0.1"
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Solaris kernels seem to rely on having the full kernel path present in
the multiboot command line; if only the kernel name is present then
the boot fails with the error message
krtld: failed to open 'unix'
Debugged-by: Michael Brown <mcb30@ipxe.org>
Debugged-by: Scott McWhirter <scottm@joyent.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Using __from_text16() and __from_data16() in inline asm constraints
sometimes defeats gcc's ability to simplify expressions down to
compile-time constants.
Reported-by: Jason Kohles <jkohles@palantir.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
At present, we always hide an extra sizeof(struct external_memory), to
account for the header on the lowest allocated block. This header
ceases to exist when there are no allocated blocks remaining.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
An ANSI escape sequence context cannot be shared between multiple
users. Make the ANSI escape sequence context part of the line console
definition and provide individual contexts for each user.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The output from text-based user interfaces such as the "config"
command is not generally meaningful for logfile-based consoles such as
syslog and vmconsole.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Add the concept of a "console usage", such as "standard output" or
"debug messages". Allow usages to be associated with each console
independently. For example, to send debugging output via the serial
port, while preventing it from appearing on the local console:
#define CONSOLE_SERIAL CONSOLE_USAGE_ALL
#define CONSOLE_PCBIOS ( CONSOLE_USAGE_ALL & ~CONSOLE_USAGE_DEBUG )
If no usages are explicitly specified, then a default set of usages
will be applied. For example:
#define CONSOLE_SERIAL
will have the same affect as
#define CONSOLE_SERIAL CONSOLE_USAGE_ALL
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Remove the name, cmdline, and action parameters from imgdownload() and
imgdownload_string(). These functions now simply download and return
an image.
Add the function imgacquire(), which will interpret a "name or URI
string" parameter and return either an existing image or a newly
downloaded image.
Use imgacquire() to merge similar image-management commands that
currently differ only by whether they take the name of an existing
image or the URI of a new image to download. For example, "chain" and
"imgexec" can now be merged.
Extend imgstat and imgfree commands to take an optional list of
images.
Remove the arbitrary restriction on the length of image names.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
There is no INT 10 call for "display character with attribute,
advancing the cursor and scrolling the screen as necessary". We
therefore make two INT 10 calls: INT 10,09 to write the character with
its attribute at the current cursor position, and then INT 10,0e to
(re)write the character (leaving the attribute unchanged), advance the
cursor position and scroll as necessary.
This confuses the serial-over-LAN console redirection feature provided
by some BIOSes.
Fix by performing the INT10,09 only when necessary to change the
existing attribute.
Reported-by: Itay Gazit <itaygazit@gmail.com>
Tested-by: Itay Gazit <itaygazit@gmail.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
RSA requires modular exponentiation using arbitrarily large integers.
Given the sizes of the modulus and exponent, all required calculations
can be done without any further dynamic storage allocation. The x86
architecture allows for efficient large integer support via inline
assembly using the instructions that take advantage of the carry flag
(e.g. "adcl", "rcrl").
This implemention is approximately 80% smaller than the (more generic)
AXTLS implementation.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Minimise code size by forcing the use of memory addresses for
__bswap_16s() and __bswap_64s(). (__bswap_32s() cannot avoid loading the
value into a register.)
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Fix a strict-aliasing error on certain versions of gcc.
Reported-by: Marko Myllynen <myllynen@redhat.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Use the "bswap" instruction to shrink the size of byte-swapping code,
and provide the in-place variants __bswap_{16,32,64}s.
"bswap" is available only on 486 and later processors. (We already
assume the presence of "cpuid" and "rdtsc", which are available only
on Pentium and later processors.)
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Some PXE stacks (observed with a QLogic 8242) will always try to
prepend a link-layer header, even if the caller uses P_UNKNOWN to
indicate that the link-layer header has already been filled in. This
results in an invalid packet being transmitted.
Work around these faulty PXE stacks where possible by stripping the
existing link-layer header and allowing the PXE stack to (re)construct
the link-layer header itself.
Originally-fixed-by: Buck Huppmann <buckh@pobox.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The RTC-based entropy source uses the nanosecond-scale CPU TSC to
measure the time between two 1kHz interrupts generated by the CMOS
RTC. In a physical machine these clocks are driven from independent
crystals, resulting in some observable clock drift. In a virtual
machine, the CMOS RTC is typically emulated using host-OS
constructions such as SIGALRM.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
ANS X9.82 specifies several Approved Sources of Entropy Input (SEI).
One such SEI uses an entropy source as the Source of Entropy Input,
condensing each entropy source output after each GetEntropy call.
This can be implemented relatively cheaply in iPXE and avoids the need
to allocate potentially very large buffers.
(Note that the terms "entropy source" and "Source of Entropy Input"
are not synonyms within the context of ANS X9.82.)
Use the iPXE API mechanism to allow entropy sources to be selected at
compilation time.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
initrd_init() calls umalloc() to allocate space for the initrd image,
but does so before hide_etherboot() has been called. It is therefore
possible for the initrd to end up overwriting iPXE itself.
Fix by converting initrd_init() from an init_fn to a startup_fn.
Originally-fixed-by: Till Straumann <strauman@slac.stanford.edu>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The command line may be situated in an area of base memory that will
be overwritten by iPXE's real-mode segments, causing the command line
to be corrupted before it can be used.
Fix by creating a copy of the command line on the prefix stack (below
0x7c00) before installing the real-mode segments.
Reported-by: Dave Hansen <dave@sr71.net>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
PXENV_FILE_EXIT_HOOK is designed to allow ipxelinux.0 to unload both
the iPXE and pxelinux components without affecting the underlying PXE
stack. Unfortunately, it causes unexpected behaviour in other
situations, such as when loading a non-embedded pxelinux.0 via
undionly.kpxe. For example:
PXE ROM -> undionly.kpxe -> pxelinux.0 -> chain.c32 to boot hd0
would cause control to return to iPXE instead of booting from the hard
disk. In some cases, this would result in a harmless but confusing
"No more network devices" message; in other cases stranger things
would happen, such as being returned to the iPXE shell prompt.
The fundamental problem is that when pxelinux detects
PXENV_FILE_EXIT_HOOK, it may attempt to specify an exit hook and then
exit back to iPXE, assuming that iPXE will in turn exit cleanly via
the specified exit hook. This is not a valid assumption in the
general case, since the action of exiting back to iPXE does not
directly cause iPXE to exit itself. (In the specific case of
ipxelinux.0, this will work since the embedded script exits as soon as
pxelinux.0 exits.)
Fix the unexpected behaviour in the non-ipxelinux.0 cases by including
support for PXENV_FILE_EXIT_HOOK only when using a new .kkkpxe format.
The ipxelinux.0 build process should therefore now use undionly.kkkpxe
instead of undionly.kkpxe.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Very nasty things can happen if a NULL network device is used. Check
that pxe_netdev is non-NULL at the applicable entry points, so that
this type of problem gets reported to the caller rather than being
allowed to crash the system.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
On at least one PXE stack (Realtek r8169), PXENV_UNDI_INITIALIZE has
been observed to fail intermittently due to a media test failure (PXE
error 0x00000061). Retrying the call to PXENV_UNDI_INITIALIZE
succeeds, and the NIC is then usable.
It is worth noting that this particular Realtek PXE stack is already
known to be unreliable: for example, it repeatably fails its own
boot-time media test after every warm reboot.
Fix by attempting PXENV_UNDI_INITIALIZE multiple times, with a short
delay between each attempt to allow the link to settle.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Allow an initrd (such as an embedded script) to be passed to iPXE when
loaded as a .lkrn (or .iso) image. This allows an embedded script to
be varied without recompiling iPXE.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Specify a driver name of "undionly" and a device name based on the
UNDI-reported underlying hardware device. For example:
net0: 52:54:00:12:34:56 using undionly on UNDI-PCI00:03.0 (open)
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Some BIOSes are reported to corrupt %ebx when using INT 15,2401 (see
http://opensolaris.org/jive/thread.jspa?messageID=377026). Guard
against this by preserving all (non-segment) registers.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The symbol_text16 is defined globally by the linker. Use rm_text16
instead of _text16 for the local variable within librm.S to avoid
confusion when reading linker maps.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
All users of imgdownload() require registration of the image, so make
registration an integral part of imgdownload() itself and simplify the
"action" parameter to be one of image_select(), image_exec() et al.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
iPXE specifies a value of 0 for cmdline_size, causing GRUB to not pass
in a command line. Fix by setting cmdline_size to the maximum value
of 2047.
Signed-off-by: Valentine Barshak <gvaxon@gmail.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Allow the link layer to directly report whether or not a packet is
multicast or broadcast at the time of calling pull(), rather than
relying on heuristics to determine this at a later stage.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Allow objects to support both streaming and block device protocols, by
starting streaming data only when the data transfer window opens.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Some bootloaders seem to add "BOOT_IMAGE=..." at the end of the
command line; some at the start. Cope with either variation.
Reported-by: Dave Hansen <dave@sr71.net>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
IBM BIOSes ignore the PnP header offset stored at address 0x1a and
instead scan for the $PnP signature on a 16-byte boundary. (This
alignment is not mandated by the PnP specification.)
Force PnP header to a 16-byte boundary to work around these BIOSes.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Several BIOSes (including most IBM BIOSes and many virtual machine
BIOSes) do not provide detectable PnP support, but will use the BEV
entry point for a PnP option ROM. On these semi-PnP BIOSes, iPXE will
respond to the absence of detectable PnP support by hooking INT19,
which disrupts the boot order.
BIOSes that genuinely require hooking INT19 seem to be very rare
nowadays. It may therefore be preferable to assume that the absence
of detectable PnP support indicates a semi-PnP BIOS rather than a
non-PnP BIOS.
Change the default behaviour so that INT19 will never be hooked unless
the compile-time option NONPNP_HOOK_INT19 is enabled. Leave the
redundant PnP detection routine in-place to allow for debugging via
the ROM banner line.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Revert commit 38cd351 ("[romprefix] Attempt to gracefully handle
semi-PnP IBM BIOSes"), since the test for the "IBM " signature in %edi
is not sufficient to identify an IBM BIOS.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Some IBM BIOSes provide partial support for PnP: they will use the BEV
entry point but will not advertise PnP support. This causes iPXE to
hook INT 19, which disrupts the boot process.
Attempt to improve this situation by detecting an IBM BIOS and
treating it as a PnP BIOS despite the absence of a PnP signature.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Some versions of binutils have curious concepts of what constitutes
subtraction. For example:
0x00000000000000f0 _text16_late = .
0x0000000000000898 _mtext16 = .
0x0000000000000898 _etext16 = .
0x0000000000000898 _text16_late_filesz = ABSOLUTE ((_mtext16 - _text16_late))
0x00000000000007a8 _text16_late_memsz = ABSOLUTE ((_etext16 - _text16_late))
This has interesting side-effects such as producing sizes for .bss
segments that are negative, causing the majority of addressable memory
to be zeroed out.
Fix by using the form
ABSOLUTE ( x ) - ABSOLUTE ( y )
rather than
ABSOLUTE ( x - y )
Reported-by: H. Peter Anvin <hpa@zytor.com>
Suggested-by: H. Peter Anvin <hpa@zytor.com>
Tested-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Michael Brown
Alex Williamson
Christian Hesse
Marin Hannache
Frediano Ziglio
Bo Yang
Joshua Oreman
Thomas Miletich
Marin Hannache
Till Straumann
Valentine Barshak