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>

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>

Originally-implemented-by: Christian Hesse <list@eworm.de>
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>

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>

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>

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>

Some prefixes (e.g. .lkrn) allow a command line to be passed in to
iPXE.  At present, this command line is ignored.

If a command line is provided, treat it as an embedded script (without
an explicit "#!ipxe" magic marker).  This allows for patterns of
invocation such as

  title  iPXE
  kernel /boot/ipxe.lkrn dhcp && \
         sanboot iscsi:10.0.4.1::::iqn.2010-04.org.ipxe.dolphin:storage

Here GRUB is instructed to load ipxe.lkrn with an embedded script
equivalent to

  #!ipxe
  dhcp
  sanboot iscsi:10.0.4.1::::iqn.2010-04.org.ipxe.dolphin:storage

This can be used to effectively vary the embedded script without
having to rebuild ipxe.lkrn.

Originally-implemented-by: Dave Hansen <dave@sr71.net>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

Some binutils versions will drag in an object to satisfy the entry
symbol; some won't.  Try to cope with this exciting variety of
behaviour by ensuring that all entry symbols are unique.

Remove the explicit inclusion of the prefix object on the linker
command line, since the entry symbol now provides all the information
needed to identify the prefix.

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

Commit 623469d ("[build] Eliminate unused sections at link-time")
introduced a regression in several build formats, in which the prefix
would end up being garbage-collected out of existence.  Fix by
ensuring that an entry symbol exists in each possible prefix, and is
required by the linker script.

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

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

Access to the gpxe.org and etherboot.org domains and associated
resources has been revoked by the registrant of the domain.  Work
around this problem by renaming project from gPXE to iPXE, and
updating URLs to match.

Also update README, LOG and COPYRIGHTS to remove obsolete information.

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

The option ROM header contains a one-byte field indicating the number
of 512-byte sectors in the ROM image.  Currently it is linked to
contain the number of uncompressed sectors, with an instruction to the
compressor to correct it.  This causes link failure when the
uncompressed size of the ROM image is over 128k.

Fix by replacing the SUBx compressor fixup with an ADDx fixup that
adds the total compressed output length, scaled as requested, to an
addend stored in the field where the final length value will be
placed.  This is similar to the behavior of ELF relocations, and
ensures that an overflow error will not be generated unless the
compressed size is still too large for the field.

This also allows us to do away with the _filesz_pgh and _filesz_sect
calculations exported by the linker script.

Output tested bitwise identical to the old SUBx mechanism on hd, dsk,
lkrn, and rom prefixes, on both 32-bit and 64-bit processors.

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

Add FILE_LICENCE declarations to almost all files that make up the
various standard builds of gPXE.

Code paths that automatically allocate memory from the FBMS at 40:13
should also free it, if possible.

Freeing this memory will not be possible if either

  1. The FBMS has been modified since our allocation, or

  2. We have not been able to unhook one or more BIOS interrupt vectors.

Not fully understood, but it seems that the LMA of bss sections matters
for some newer binutils builds.  Force all bss sections to have an LMA
at the end of the file, so that they don't interfere with other
sections.

The symptom was that objcopy -O binary -j .zinfo would extract the
.zinfo section from bin/xxx.tmp as a blob of the correct length, but
with zero contents.  This would then cause the [ZBIN] stage of the
build to fail.

Also explicitly state that .zinfo(.*) sections have @progbits, in case
some future assembler or linker variant decides to omit them.

Reduce the number of sections within the linker script to match the
number of practical sections within the output file.

Define _section, _msection, _esection, _section_filesz, _section_memsz,
and _section_lma for each section, replacing the mixture of symbols that
previously existed.

In particular, replace _text and _end with _textdata and _etextdata, to
make it explicit within code that uses these symbols that the .text and
.data sections are always treated as a single contiguous block.

H. Peter Anvin <hpa@zytor.com> sent word that Sergey Vlasov
<vsu@altlinux.ru> discovered gPXE lkrn images fail to load in SYSLINUX
3.70 because we have initrd_addr_max zeroed.  This patch sets the same
value as the Linux kernel.

Also change the header jmp instruction to use a hardcoded opcode value
like Linux does.  Just in case the assembler decides to use a three-byte
instruction instead of the desired two-byte jmp.

compressor fixup section.

mechanism has changed anyway, and so must be rewritten, but at least doing
this makes the output of "make symcheck" more legible.