RFC: Add PT_GNU_PROPERTY to cover .note.gnu.property section

Cary Coutant ccoutant@gmail.com
Wed Dec 12 16:12:00 GMT 2018

> > > As you might expect, I support this new program header. Ideally, I'd
> > > have liked to replace the input SHT_NOTE sections with
> > > SHT_GNU_PROPERTY sections and dispense with all the note section
> > > overhead, but I'll take this as a compromise.
> >
> > Why can't we switch to SHT_GNU_PROPERTY? My fear with combining
> > PT_GNU_PROPERTY with SHT_NOTE is that it will be even more confusing
> There is no requirement for PT_XXX to have SHT_XXX, like PT_GNU_RELRO.

But it is not normal for the linker to perform such special processing
on an SHT_NOTE section. When a section requires special processing, it
is customary to use a new section type. Otherwise, the linker has to
resort to string matching on the section name. Section names in ELF
are not supposed to have special meaning to the linker.

> > Also I thought there was still a question whether any or all
> > newly proposed property features and flags are actually needed
> > as loadable segments. There is a clear overlap with the GNU
> > Attributes (which are non-loadable). I would like to see consensus
> > first on the new property format/flags and which are and which
> > aren't needed as loadable properties at runtime.
> Yes, they are needed in loadable segment.  That is the main motivation
> for GNU program property,

The only properties required in a loadable segment are those that will
be used by the loader. From what I can tell so far, the USED bits
can't be used by the loader, so why can't they go in the GNU
attributes section?


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