From: Florian Weimer <fweimer@redhat.com>
To: "H.J. Lu" <hjl.tools@gmail.com>
Cc: Binutils <binutils@sourceware.org>,
GNU C Library <libc-alpha@sourceware.org>,
gnu-gabi@sourceware.org, x86-64-abi@googlegroups.com
Subject: Re: RFC: Linux gABI: Add a GNU_PROPERTY_BY_LINKER property
Date: Mon, 01 Jan 2018 00:00:00 -0000 [thread overview]
Message-ID: <87ftvoouda.fsf@oldenburg.str.redhat.com> (raw)
In-Reply-To: <CAMe9rOqk-s5LHb0dAOZJ=GdLeUgqY-sdx3GLBLeBsnM=kU1dZQ@mail.gmail.com> (H. J. Lu's message of "Sat, 24 Nov 2018 08:21:07 -0800")
* H. J. Lu:
> GNU_PROPERTY_X86_UINT32_VALID was defined to address this issue such that
> linker sets the bit in values of x86 properties for non-relocatable
> outputs. But it isn't sufficient:
>
> 1. It doesn't cover generic properties.
Okay.
> 2. When -mx86-used-note=yes is passed to x86 assembler, the
> GNU_PROPERTY_X86_UINT32_VALID bit is set in GNU_PROPERTY_X86_ISA_1_USED
> property in object file and linkers without GNU property support generate
> invalid NT_GNU_PROPERTY_TYPE_0 notes with the GNU_PROPERTY_X86_UINT32_VALID
> bit set.
Surely this is a GAS bug? Why not fix that bug?
> I am proposing the following changes:
>
> 1. Add a GNU_PROPERTY_BY_LINKER property which should only be set by
> linker for non-relocatable outputs to indicate the property note is
> valid and generated by new linkers. Loaders can check this property
> to verify that the property note is valid.
> 2. Remove GNU_PROPERTY_X86_UINT32_VALID.
> 3. Define GNU_PROPERTY_X86_ISA_1_BASE for GNU_PROPERTY_X86_ISA_1_USED,
> which has the same bit as GNU_PROPERTY_X86_UINT32_VALID and use it
> for -mx86-used-note=yes with x86 assembler.
The alternative approach would be to switch to a new PT_ segment for
this because those aren't included in relocatable objects. (Maybe it's
time for another approach.)
Thanks,
Florian
next prev parent reply other threads:[~2018-11-26 13:12 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-01 0:00 H.J. Lu
2018-01-01 0:00 ` Florian Weimer [this message]
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 ` H.J. Lu
2018-01-01 0:00 ` Cary Coutant
2018-01-01 0:00 ` H.J. Lu
2018-01-01 0:00 ` Szabolcs Nagy
2018-01-01 0:00 ` H.J. Lu
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