At some point in the past few years, binutils became more aggressive
at removing unused symbols. To function as a symbol requirement, a
relocation record must now be in a section marked with @progbits and
must not be in a section which gets discarded during the link (either
via --gc-sections or via /DISCARD/).
Update REQUIRE_SYMBOL() to generate relocation records meeting these
criteria. To minimise the impact upon the final binary size, we use
existing symbols (specified via the REQUIRING_SYMBOL() macro) as the
relocation targets where possible. We use R_386_NONE or R_X86_64_NONE
relocation types to prevent any actual unwanted relocation taking
place. Where no suitable symbol exists for REQUIRING_SYMBOL() (such
as in config.c), the macro PROVIDE_REQUIRING_SYMBOL() can be used to
generate a one-byte-long symbol to act as the relocation target.
If there are versions of binutils for which this approach fails, then
the fallback will probably involve killing off REQUEST_SYMBOL(),
redefining REQUIRE_SYMBOL() to use the current definition of
REQUEST_SYMBOL(), and postprocessing the linked ELF file with
something along the lines of "nm -u | wc -l" to check that there are
no undefined symbols remaining.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
These files cannot be automatically relicensed by util/relicense.pl
since they either contain unusual but trivial contributions (such as
the addition of __nonnull function attributes), or contain lines
dating back to the initial git revision (and so require manual
knowledge of the code's origin).
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The code in lzma_literal() checks to see if we are at the start of the
compressed input data in order to determine whether or not a most
recent output byte exists. This check is incorrect, since
initialisation of the decompressor will always consume the first five
bytes of the compressed input data.
Fix by instead checking whether or not we are at the start of the
output data stream. This is, in any case, a more logical check.
This issue was masked during development and testing since virtual
machines tend to zero the initial contents of RAM; the spuriously-read
"most recent output byte" is therefore likely to already be a zero
when running in a virtual machine.
Reported-by: Robin Smidsrød <robin@smidsrod.no>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The 0xe9 debug port exists only on virtual machines. Provide an
option to print debug output on the BIOS console, to allow for
debugging on real hardware.
Note that this option can be used only if the decompressor is called
in flat real mode; the easiest way to achieve this is to build with
DEBUG=libprefix.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Allow the decompressor the option of generating debugging output via
the BIOS console by calling it in flat real mode (rather than 16-bit
protected mode) when libprefix.S is built with debugging enabled.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
LZMA performs an extra normalisation after decompression is complete,
which does not affect the output but may consume an extra byte from
the input (and so may affect which byte is identified as being the
start of the next block).
Reported-by: Robin Smidsrød <robin@smidsrod.no>
Tested-by: Robin Smidsrød <robin@smidsrod.no>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
LZMA provides significantly better compression (by ~15%) than the
current NRV2B algorithm.
We use a raw LZMA stream (aka LZMA1) to avoid the need for code to
parse the LZMA2 block headers. We use parameters {lc=2,lp=0,pb=0} to
reduce the stack space required by the decompressor to acceptable
levels (around 8kB). Using lc=3 or pb=2 would give marginally better
compression, but at the cost of substantially increasing the required
stack space.
The build process now requires the liblzma headers to be present on
the build system, since we do not include a copy of an LZMA compressor
within the iPXE source tree. The decompressor is written from scratch
(based on XZ Embedded) and is entirely self-contained within the
iPXE source.
The branch-call-jump (BCJ) filter used to improve the compressibility
is specific to iPXE. We choose not to use liblzma's built-in BCJ
filter since the algorithm is complex and undocumented. Our BCJ
filter achieves approximately the same results (on typical iPXE
binaries) with a substantially simpler algorithm.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Some decompression algorithms (e.g. LZMA) require large amounts of
temporary stack space, which may not be made available by all
prefixes. Use .bss16 as a temporary stack for the duration of the
calls to install_block (switching back to the external stack before we
start making calls into code which might access variables in .bss16),
and allow the decompressor to define a global symbol to force a
minimum value on the size of .bss16.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The 8254 timer code (used to implement udelay()) has an unknown
provenance. Rewrite this code to avoid potential licensing
uncertainty.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Hardened versions of gcc default to building position-independent
code, which breaks our i386 build. Our build process therefore
detects such platforms and automatically adds "-fno-PIE -nopie" to the
gcc command line.
On x86_64, we choose to build position-independent code (in order to
reduce the final binary size and, in particular, the number of
relocations required for UEFI binaries). The workaround therefore
breaks the build process for x86_64 binaries on such platforms.
Fix by moving the workaround to the i386-specific portion of the
Makefile.
Reported-by: Jan Kundrát <jkt@kde.org>
Debugged-by: Jan Kundrát <jkt@kde.org>
Debugged-by: Marin Hannache <git@mareo.fr>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Use PRODUCT_SHORT_NAME instead of a hardcoded "iPXE" for strings which
are typically shown in the user interface.
Note that this only allows for customisation of the user interface.
Where the "iPXE" string serves a technical purpose (such as in the
HTTP User-Agent), the string cannot be customised.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Some devices return multiple packets in a single poll. Handle such
devices gracefully by enqueueing received PXE UDP packets (along with
a pseudo-header to hold the IPv4 addresses and port numbers) and
dequeueing them on subsequent calls to PXENV_UDP_READ.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Fetching the TFTP file size is currently implemented via a custom
"tftpsize://" protocol hack. Generalise this approach to instead
close the TFTP connection whenever the parent data-transfer interface
is closed.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Allow drivers to specify a supported PCI class code. To save space in
the final binary, make this an attribute of the driver rather than an
attribute of a PCI device ID list entry.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The EDK2 codebase uses -malign-double for 32-bit builds, which causes
64-bit integers to be naturally aligned. This affects the layout of
some structures (including EFI_BLOCK_IO_MEDIA).
This mirrors wimboot commit 7b8f39d ("[build] Fix building of 32-bit
UEFI version").
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The .mrom payload has a code type of 0xff and so the initialisation
length field (single byte at offset 0x02) does not need to be
present. Use only the PCI header's image length field, which allows
the .mrom payload to be up to 32MB in size.
Inspired-by: Swift Geek <swiftgeek@gmail.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
mromprefix.S currently uses the initialisation length field (single
byte at offset 0x02) to determine the length of a ROM image within a
multi-image ROM BAR. For PCI ROM images with a code type other than
0, the initialisation length field may not be present.
Fix by using the PCI header's image length field instead.
Inspired-by: Swift Geek <swiftgeek@gmail.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The build process has for a long time assumed that every ROM is a PCI
ROM, and will always include the PCI header and PCI-related
functionality (such as checking the PCI BIOS version, including the
PCI bus:dev.fn address within the ROM product name string, etc.).
While real ISA cards are no longer in use, some virtualisation
environments (notably VirtualBox) have support only for ISA ROMs.
This can cause problems: in particular, VirtualBox will call our
initialisation entry point with random garbage in %ax, which we then
treat as the PCI bus:dev.fn address of the autoboot device: this
generally prevents the default boot sequence from using any network
devices.
Create .isarom and .pcirom prefixes which can be used to explicitly
specify the type of ROM to be created. (Note that the .mrom prefix
always implies a PCI ROM, since the .mrom mechanism relies on
reconfiguring PCI BARs.)
Make .rom a magic prefix which will automatically select the
appropriate PCI or ISA ROM prefix for ROMs defined via a PCI_ROM() or
ISA_ROM() macro. To maintain backwards compatibility, we default to
building a PCI ROM for anything which is not directly derived from a
PCI_ROM() or ISA_ROM() macro (e.g. bin/intel.rom).
Add a selection of targets to "make everything" to ensure that the
(relatively obscure) ISA ROM build process is included within the
per-commit QA checks.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Since some PnP BIOSes fail to set %es:di to point to the PnP signature
on entry, we identify a PnP BIOS by scanning through the top 64kB of
base memory looking for the PnP structure. We therefore don't
actually use the values of %es:di provided to the initialisation entry
point, and so there is no need to preserve them.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Some external code (observed with FreeBSD's bootloader) will continue
to make INT 13 calls after reconfiguring the 8259 PIC to change the
vector offsets for IRQs. If an IRQ (e.g. the timer IRQ) subsequently
occurs while iPXE is in protected mode, this will cause a general
protection fault since the corresponding IDT entry is empty.
A general protection fault is INT 0x0d, which happens to overlap with
the original IRQ5. We therefore do have an ISR set up to handle a
general protection fault, but this ISR simply reflects the interrupt
down to the real-mode INT 0x0d and then attempts to return. Since our
ISR is expecting a hardware interrupt rather than a general protection
fault, it doesn't remove the error code from the stack before issuing
the iret instruction; it therefore attempts to return to a garbage
address. Since the segment part of this address is likely to be
invalid, a second general protection fault occurs. This cycle
continues until we run out of stack space and triple fault.
Fix by reflecting all INTs down to real mode. This actually reduces
the code size by four bytes (but increases the bss size by almost
2kB).
Reported-by: Brian Rak <dn@devicenull.org>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The bzImage boot protocol allows the real-mode code to be loaded at
any segment within base memory. (The fact that both iPXE and recent
versions of Syslinux will load the real-mode code at 1000:0000 is a
coincidence; it is not guaranteed by the specification.)
Fix by making the code relocatable.
Reported-by: Andrew Stuart <andrew@shopcusa.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Rework geniso and genliso to provide a single merged utility for
generating ISO images.
Modified-by: Michael Brown <mcb30@ipxe.org>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The .lkrn prefix currently provides a zImage kernel with unused setup
sectors and the whole iPXE binary placed within the "protected mode
kernel" portion of the zImage.
The work carried out years ago to create the .mrom format provides a
mechanism allowing the iPXE binary to be split into a small real-mode
header and a larger payload. This neatly matches the way that a
bzImage is loaded: the "setup sectors" can contain the header and the
"protected mode kernel" can contain the payload.
This removes the size restrictions on an iPXE .lkrn image (and hence
on derived image formats such as .iso).
Also remove obsolete copyright information, since none of the original
code or functionality now remains.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Interrupt processing adds noise to profiling results. Allow
interrupts (from within protected mode) to be profiled separately,
with time spent within the interrupt handler being excluded from any
other profiling currently in progress.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
PXENV_UNDI_ISR calls may implicitly refill the underlying receive
ring, and so could continue to retrieve packets indefinitely. Place
an upper limit on the number of calls to PXENV_UNDI_ISR per call to
undinet_poll().
Signed-off-by: Michael Brown <mcb30@ipxe.org>
