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From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Wed, 19 Feb 2020 12:28:00 -0000
Message-ID: <CAMe9rOpgwi0M9XqbeyUm+LLuqypObZBmEGEAgFAyDeUYck5ucA@mail.gmail.com>
Subject: Re: binutils ld and new PT_GNU_PROPERTY segment
To: Mark Wielaard <mark@klomp.org>
Cc: Fangrui Song <maskray@google.com>, "Zhang, Annita" <annita.zhang@intel.com>, 	gnu-gabi <gnu-gabi@sourceware.org>, Binutils <binutils@sourceware.org>
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On Wed, Feb 19, 2020 at 4:02 AM Mark Wielaard <mark@klomp.org> wrote:
>
> Hi,
>
> On Wed, 2020-02-19 at 03:39 -0800, H.J. Lu wrote:
> > On Wed, Feb 19, 2020 at 2:58 AM Mark Wielaard <mark@klomp.org> wrote:
> > > On Tue, 2020-02-18 at 18:31 -0800, Fangrui Song wrote:
> > > >  From what I can see, neither the Linux kernel nor glibc uses
> > > > PT_GNU_PROPERTY.
> > > > glibc/sysdeps/x86/dl-prop.h parses PT_NOTE.
> > >
> > > That is my impression too.
> >
> > See:
> >
> > https://patchwork.kernel.org/patch/11285409/
> >
> > It is for both x86 and arm64.
>
> So that is not upstream in the mainline kernel? Why can't that patch
> use the existing PT_NOTE segment? That would make it compatible with
> existing binaries that don't have this PT_GNU_PROPERTY program header.

Kernel loader is one of motivations of PT_GNU_PROPERTY.  Kernel loader
only wants to check PT_XXX.

-- 
H.J.