From: "H.J. Lu" <hjl.tools@gmail.com>
To: Florian Weimer <fweimer@redhat.com>
Cc: GNU C Library <libc-alpha@sourceware.org>
Subject: Re: [RFC] DT_X86_64_PLT* dependency
Date: Tue, 3 Oct 2023 00:44:26 -0700 [thread overview]
Message-ID: <CAMe9rOofycKUC5cNpEMr3QkmnWXQGE2ASpSqdOn+373Zy0mJRw@mail.gmail.com> (raw)
In-Reply-To: <875y3pe2wh.fsf@oldenburg.str.redhat.com>
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On Mon, Oct 2, 2023, 6:26 PM Florian Weimer <fweimer@redhat.com> wrote:
> * H. J. Lu:
>
> > When these tags are generated, the r_addend field of the
> R_X86_64_JUMP_SLOT
> > relocation stores the offset of the indirect branch instruction.
> However, glibc
> > versions which don't have this commit in glibc 2.36:
> >
> > commit f8587a61892cbafd98ce599131bf4f103466f084
> > Author: H.J. Lu <hjl.tools@gmail.com>
> > Date: Fri May 20 19:21:48 2022 -0700
> >
> > x86-64: Ignore r_addend for R_X86_64_GLOB_DAT/R_X86_64_JUMP_SLOT
> >
> > According to x86-64 psABI, r_addend should be ignored for
> R_X86_64_GLOB_DAT
> > and R_X86_64_JUMP_SLOT. Since linkers always set their r_addends to
> 0, we
> > can ignore their r_addends.
> >
> > Reviewed-by: Fangrui Song <maskray@google.com>
> >
> > won't ignore the r_addend value in the R_X86_64_JUMP_SLOT relocation.
> Such
> > binaries will fail to run with these versions of glibc. I am working
> > on a linker patch
> > to add a glibc version dependency similar to GLIBC_ABI_DT_RELR for
> DT_RELR.
> > Although this commit has been backported to glibc 2.33/2.34/2.35
> > release branches,
> > there may be 2.33/2.34/2.35 glibc binaries without the fix.
>
> Can we reuse the GLIBC_ABI_DT_RELR marker?
>
Do all versions of glibc with DT_RELR support
also ignore r_addend?
>
> > Should binaries with DT_X86_64_PLT tags depend on glibc 2.36 or 2.33?
>
> I don't understand this question. The binaries will run on any system
> that has the marker symbol. Or do you suggest to use an existing glibc
> symbol version?
>
Yes, I am planning to use existing glibc symbol
version.
> Thanks,
> Florian
>
H.J.
prev parent reply other threads:[~2023-10-03 7:44 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-29 15:16 H.J. Lu
2023-10-02 10:26 ` Florian Weimer
2023-10-03 7:44 ` H.J. Lu [this message]
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