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From: Cary Coutant <ccoutant@gmail.com>
To: "H.J. Lu" <hjl.tools@gmail.com>
Cc: Mark Wielaard <mark@klomp.org>,
	Florian Weimer <fweimer@redhat.com>,
		Binutils <binutils@sourceware.org>,
	GNU C Library <libc-alpha@sourceware.org>,
		gnu-gabi@sourceware.org,
	x86-64-abi <x86-64-abi@googlegroups.com>
Subject: Re: RFC: Add PT_GNU_PROPERTY to cover .note.gnu.property section
Date: Mon, 01 Jan 2018 00:00:00 -0000	[thread overview]
Message-ID: <CAJimCsFWo+j0PbK_B8UM0XnkkFzW2z7qpDWpNRhTv3hb0hFMug@mail.gmail.com> (raw)
In-Reply-To: <CAMe9rOrgOu_EYnxqXOZa54Q0a36126a2o-DMFRVqv45Uor82pw@mail.gmail.com>

> > > 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?

-cary

  reply	other threads:[~2018-12-12 16:12 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-01  0:00 RFC: Linux gABI: Add a GNU_PROPERTY_BY_LINKER property H.J. Lu
2018-01-01  0:00 ` Florian Weimer
2018-01-01  0:00   ` H.J. Lu
2018-01-01  0:00     ` Cary Coutant
2018-01-01  0:00       ` H.J. Lu
2018-01-01  0:00         ` Florian Weimer
2018-01-01  0:00           ` H.J. Lu
2018-01-01  0:00             ` Cary Coutant
2018-01-01  0:00               ` H.J. Lu
2018-01-01  0:00                 ` H.J. Lu
2018-01-01  0:00                   ` RFC: Add PT_GNU_PROPERTY to cover .note.gnu.property section H.J. Lu
2018-01-01  0:00                     ` H.J. Lu
2018-01-01  0:00                       ` Florian Weimer
2018-01-01  0:00                         ` H.J. Lu
2018-01-01  0:00                           ` Cary Coutant
2018-01-01  0:00                             ` Mark Wielaard
2018-01-01  0:00                               ` Szabolcs Nagy
2018-01-01  0:00                               ` H.J. Lu
2018-01-01  0:00                                 ` Cary Coutant [this message]
2018-01-01  0:00                                   ` H.J. Lu
2018-01-01  0:00                       ` H.J. Lu

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