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>

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resources has been revoked by the registrant of the domain.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>

Try to avoid future problems caused by implicit section flags and/or
type information by instituting a policy that all .section
declarations must explicitly state the flags and type.

Most of this change was achieved using

    perl -pi \
      -e 's/".text"$/".text", "ax", \@progbits/ ; ' \
      -e 's/".text16"$/".text16", "ax", \@progbits/ ; ' \
      -e 's/".text16.null"$/".text16.null", "ax", \@progbits/ ; ' \
      -e 's/".text16.data"$/".text16.data", "aw", \@progbits/ ; ' \
      -e 's/".data"$/".data", "aw", \@progbits/ ; ' \
      -e 's/".data16"$/".data16", "aw", \@progbits/ ; ' \
      -e 's/".bss"$/".bss", "aw", \@nobits/ ; ' \
      -e 's/".bss16"$/".bss16", "aw", \@nobits/ ; ' \
      -e 's/".prefix"$/".prefix", "ax", \@progbits/ ; ' \
      -e 's/".prefix.lib"$/".prefix.lib", "awx", \@progbits/ ; ' \
      -e 's/".prefix.data"$/".prefix.data", "aw", \@progbits/ ; ' \
      -e 's/".weak"$/".weak", "a", \@nobits/ ; ' \
      `git grep -l '\.section'`

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.

compressor fixup section.