The mbr.bin and usbdisk.bin standalone blobs are currently generated
using "objcopy -O binary", which does not process relocation records.

For the i386 build, this does not matter since the section start
address is zero and so the ".rel" relocation records are effectively
no-ops anyway.

For the x86_64 build, the ".rela" relocation records are not no-ops,
since the addend is included as part of the relocation record (rather
than inline).  Using "objcopy -O binary" will silently discard the
relocation records, with the result that all symbols are effectively
given a value of zero.

Fix by using "ld --oformat binary" instead of "objcopy -O binary" to
generate mbr.bin and usbdisk.bin.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

Move most arch/i386 files to arch/x86, and adjust the contents of the
Makefiles and the include/bits/*.h headers to reflect the new
locations.

This patch makes no substantive code changes, as can be seen using a
rename-aware diff (e.g. "git show -M5").

This patch does not make the pcbios platform functional for x86_64; it
merely allows it to compile without errors.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

Signed-off-by: Michael Brown <mcb30@ipxe.org>

Some distributions (observed with Ubuntu 15.04) place ldlinux.c32 in a
separate directory from isolinux.bin.  Search for these files
separately, and allow an alternative location of ldlinux.c32 to be
provided via LDLINUX_C32=... on the make command line.

Reported-by: Adrian Koshka <adriankoshcha@teknik.io>
Tested-by: Adrian Koshka <adriankoshcha@teknik.io>
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>

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>

Signed-off-by: Michael Brown <mcb30@ipxe.org>

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>

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>

An iPXE .exe image can be loaded from DOS.  Tested using bin/ipxe.exe
to load a Linux kernel and simple initramfs from within MS-DOS 6.22.
(EDD must be disabled using the "edd=off" kernel parameter, since the
loaded kernel image has already overwritten parts of DOS' INT 13
wrapper.)

Signed-off-by: Michael Brown <mcb30@ipxe.org>

Originally-fixed-by: Piotr Jaroszyński <p.jaroszynski@gmail.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

Signed-off-by: Piotr Jaroszyński <p.jaroszynski@gmail.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

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>

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.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

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.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

The .hrom prefix provides an experimental mechanism for reducing
option ROM space usage on systems where PMM allocation fails, by
pretending that PMM allocation succeeded and gave us an address fixed
at compilation time.  This is unreliable, and potentially dangerous.
In particular, when multiple gPXE ROMs are present in a system, each
gPXE ROM will assume ownership of the same fixed address, resulting in
undefined behaviour.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

The .xrom prefix provides an experimental mechanism for loading ROM
images greater than 64kB in size by mapping the expansion ROM BAR in
at a hopefully-unused address.  This is unreliable, and potentially
dangerous.  In particular, there is no guarantee that any PCI bridges
between the CPU and the device will respond to accesses for the
"unused" memory region that is chosen, and it is possible that the
process of scanning for the "unused" memory region may end up issuing
reads to other PCI devices.  If this ends up trampling on a register
with read side-effects belonging to an unrelated PCI device, this may
cause undefined behaviour.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

The .elf, .elfd, .lmelf, and .lmelfd prefices were brought over from
legacy Etherboot and they do not build in gPXE.  This patch removes the
ELF prefices.

Signed-off-by: Stefan Hajnoczi <stefanha@gmail.com>
Signed-off-by: Marty Connor <mdc@etherboot.org>

The unfinished .exe prefix was brought over from legacy Etherboot.
There has been no demand for .exe images so this patch removes the
prefix.

Signed-off-by: Stefan Hajnoczi <stefanha@gmail.com>
Signed-off-by: Marty Connor <mdc@etherboot.org>

The DOS .com prefix was brought over from legacy Etherboot but does not
build.  There has been no demand for .com images so this patch removes
the prefix.

Signed-off-by: Stefan Hajnoczi <stefanha@gmail.com>
Signed-off-by: Marty Connor <mdc@etherboot.org>

The .lkrn prefix allows gPXE to be loaded as a Linux bzImage.  The
bImage prefix was carried over from legacy Etherboot and does not build.
This patch removes the .bImage prefix, use .lkrn instead.

Signed-off-by: Stefan Hajnoczi <stefanha@gmail.com>
Signed-off-by: Marty Connor <mdc@etherboot.org>

The standard option ROM format provides a header indicating the size
of the entire ROM, which the BIOS will reserve space for, load, and
call as necessary. However, this space is strictly limited to 128k for
all ROMs. gPXE ameliorates this somewhat by reserving space for itself
in high memory and relocating the majority of its code there, but on
systems prior to PCI3 enough space must still be present to load the
ROM in the first place. Even on PCI3 systems, the BIOS often limits the
size of ROM it will load to a bit over 64kB.

These space problems can be solved by providing an artificially small
size in the ROM header: just enough to let the prefix code (at the
beginning of the ROM image) be loaded by the BIOS. To the BIOS, the
gPXE ROM will appear to be only a few kilobytes; it can then load
the rest of itself by accessing the ROM directly using the PCI
interface reserved for that task.

There are a few problems with this approach. First, gPXE needs to find
an unmapped region in memory to map the ROM so it can read from it;
this is done using the crude but effective approach of scanning high
memory (over 0xF0000000) for a sufficiently large region of all-ones
(0xFF) reads. (In x86 architecture, all-ones is returned for accesses
to memory regions that no mapped device can satisfy.) This is not
provably valid in all situations, but has worked well in practice.
More importantly, this type of ROM access can only work if the PCI ROM
BAR exists at all. NICs on physical add-in PCI cards generally must
have the BAR in order for the BIOS to be able to load their ROM, but
ISA cards and LAN-on-Motherboard cards will both fail to load gPXE
using this scheme.

Due to these uncertainties, it is recommended that .xrom only be used
when a regular .rom image is infeasible due to crowded option ROM
space. However, when it works it could allow loading gPXE images
as large as a flash chip one could find - 128kB or even higher.

Signed-off-by: Marty Connor <mdc@etherboot.org>

gPXE currently takes advantage of the feature of PCI3.0 that allows
option ROMs to relocate the bulk of their code to high memory and so
take up only a small amount of space in the option ROM area. Currently,
the relocation can only take place if the BIOS's implementation of PMM
can be made to return blocks aligned to an even megabyte, because of
the A20 gate. AMI BIOSes, in particular, will not return allocations
that gPXE can use.

Ameliorate the situation somewhat by adding a prefix, .hrom, that works
identically to .rom except in the case that PMM allocation fails. Where
.rom would give up and place itself entirely in option ROM space, .hrom
moves to a block (assumed free) at HIGHMEM_LOADPOINT = 4MB. This allows
for the use of larger gPXE ROMs than would otherwise be possible.

Because there is no way to check that the area at HIGHMEM_LOADPOINT is
really free, other devices using that memory during the boot process
will cause failure for gPXE, the other device, or both. In practice
such conflicts will likely not occur, but this prefix should still be
considered EXPERIMENTAL.

Signed-off-by: Marty Connor <mdc@etherboot.org>

The disk partition prefix code in hdprefix.S reads the gPXE image in
tracks, not individual sectors.  This means it will attempt to read
beyond the end of the image if the .hd image type is not padded to 32
KB.

This issue is affects virtualization software which may execute a .hd or
.usb image file directly - effectively running a machine with a tiny
disk containing just the gPXE image.  Boot will fail when gPXE tries to
read beyond the end of disk.

We add a syslinux floppy disk type using parts of the genliso script.
This floppy image cat be dd'ed to a physical floppy or used in
instances where a virtual floppy with an mountable DOS filesystem is
useful.

We also modify the genliso script to only generate .liso images
rather than creating images depending on how it is called.

Signed-off-by: Michael Brown <mcb30@etherboot.org>

Some utilities that expect a floppy disk image (e.g. iLO?) may test
for a file of the correct size.  Reinstate the .pdsk image format in
order to provide this if needed.

QEMU will silently round down a disk or ROM image file to the nearest
512 bytes.  Fix by always padding .rom, .dsk and .hd images to the
nearest 512-byte boundary.

Originally-fixed-by: Stefan Hajnoczi <stefanha@gmail.com>

Certain combinations of PXE stack and BIOS result in a broken INT 18
call, which will leave the system displaying a "PRESS ANY KEY TO
REBOOT" message instead of proceeding to the next boot device.  On
these systems, returning via the PXE stack is the only way to continue
to the next boot device.  Returning via the PXE stack works only if we
haven't already blown away the PXE base code in pxeprefix.S.

In most circumstances, we do want to blow away the PXE base code.
Base memory is a limited resource, and it is desirable to reclaim as
much as possible.  When we perform an iSCSI boot, we need to place the
iBFT above the 512kB mark, because otherwise it may not be detected by
the loaded OS; this may not be possible if the PXE base code is still
occupying that memory.

Introduce a new prefix type .kkpxe which will preserve both the PXE
base code and the UNDI driver (as compared to .kpxe, which preserves
the UNDI driver but uninstalls the PXE base code).  This prefix type
can be used on systems that are known to experience the specific
problem of INT 18 being broken, or in builds (such as gpxelinux.0) for
which it is particularly important to know that returning to the BIOS
will work.

Written by H. Peter Anvin <hpa@zytor.com> and Stefan Hajnoczi
<stefanha@gmail.com>, minor structural alterations by Michael Brown
<mcb30@etherboot.org>.