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From: "cvs-commit at gcc dot gnu.org" <sourceware-bugzilla@sourceware.org>
To: glibc-bugs@sourceware.org
Subject: [Bug dynamic-link/27072] static pie ifunc resolvers run before hwcap is setup
Date: Thu, 21 Jan 2021 15:59:51 +0000	[thread overview]
Message-ID: <bug-27072-131-GChlwXJQiI@http.sourceware.org/bugzilla/> (raw)
In-Reply-To: <bug-27072-131@http.sourceware.org/bugzilla/>

https://sourceware.org/bugzilla/show_bug.cgi?id=27072

--- Comment #8 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Szabolcs Nagy <nsz@sourceware.org>:

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=86d439b06fb29af8d063ee8855ff63a863f46ef3

commit 86d439b06fb29af8d063ee8855ff63a863f46ef3
Author: Szabolcs Nagy <szabolcs.nagy@arm.com>
Date:   Tue Jan 19 17:17:01 2021 +0000

    csu: Move static pie self relocation later [BZ #27072]

    IFUNC resolvers may depend on tunables and cpu feature setup so
    move static pie self relocation after those.

    It is hard to guarantee that the ealy startup code does not rely
    on relocations so this is a bit fragile. It would be more robust
    to handle RELATIVE relocs early and only IRELATIVE relocs later,
    but the current relocation processing code cannot do that.

    The early startup code up to relocation processing includes

      _dl_aux_init (auxvec);
      __libc_init_secure ();
      __tunables_init (__environ);
      ARCH_INIT_CPU_FEATURES ();
      _dl_relocate_static_pie ();

    These are simple enough that RELATIVE relocs can be avoided.

    The following steps include

      ARCH_SETUP_IREL ();
      ARCH_SETUP_TLS ();
      ARCH_APPLY_IREL ();

    On some targets IRELATIVE processing relies on TLS setup on
    others TLS setup relies on IRELATIVE relocs, so the right
    position for _dl_relocate_static_pie is target dependent.
    For now move self relocation as early as possible on targets
    that support static PIE.

    Fixes bug 27072.

    Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

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  parent reply	other threads:[~2021-01-21 15:59 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-15 11:01 [Bug dynamic-link/27072] New: " nsz at gcc dot gnu.org
2020-12-15 11:38 ` [Bug dynamic-link/27072] " fweimer at redhat dot com
2021-01-07 12:42 ` hjl.tools at gmail dot com
2021-01-07 14:00 ` nsz at gcc dot gnu.org
2021-01-07 17:10 ` hjl.tools at gmail dot com
2021-01-07 20:33 ` hjl.tools at gmail dot com
2021-01-13 19:20 ` i at maskray dot me
2021-01-19 14:39 ` cvs-commit at gcc dot gnu.org
2021-01-21 15:59 ` cvs-commit at gcc dot gnu.org
2021-01-21 15:59 ` cvs-commit at gcc dot gnu.org [this message]
2021-01-21 17:06 ` adhemerval.zanella at linaro dot org
2021-01-21 18:23 ` hjl.tools at gmail dot com

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