The ET_DYN path computes run-time addresses from link-time ones in five
places, each open-coding the arithmetic, and two of them disagree about
how: libelf_relocatedyn() adds textalloc to a relocation's r_offset in
one branch and subtracts datasec before adding datastart in the next,
while the value translation a few lines further down picks between those
two forms with an explicit test on datasec.
Collect that into libelf_addr(), which makes the test once: an address
below the data segment's link-time base belongs to text, anything at or
above it to data.
This changes nothing today. libelf_elfsize() sets
segpad = datasec - (text_vaddr + textsize)
and libelf_load() then places
datastart = textalloc + textsize + segpad
so datastart - datasec is textalloc, and the data branch reduces to
textalloc + vaddr -- exactly what the text branch returns, and exactly
what adding a single load bias did before. The two forms are the same
arithmetic written twice.
They stop being the same once text and data are placed independently,
which is what an FDPIC object requires: its two PT_LOAD segments are
relocated separately so that the read-only one can be mapped in place on
the media while only the writable one is copied. Having the translation
in one function is what makes that possible without auditing every
open-coded expression again.
Built for mps3-an547:picostest, which is CONFIG_ELF with CONFIG_PIC, and
boots identically to the same configuration without this change.
Assisted-by: Claude Opus 5 (1M context) <noreply@anthropic.com>
Signed-off-by: Marco Casaroli <marco.casaroli@gmail.com>
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