[Bug dynamic-link/27072] static pie ifunc resolvers run before hwcap is setup

["cvs-commit at gcc dot gnu.org" <sourceware-bugzilla@sourceware.org>]

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

--- Comment #7 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=47618209d05a0e77932038f21c6bba2425bd75c6

commit 47618209d05a0e77932038f21c6bba2425bd75c6
Author: Szabolcs Nagy <szabolcs.nagy@arm.com>
Date:   Fri Jan 15 12:49:24 2021 +0000

    Use hidden visibility for early static PIE code

    Extern symbol access in position independent code usually involves GOT
    indirection which needs RELATIVE reloc in a static linked PIE. (On
    some targets this is avoided e.g. because the linker can relax a GOT
    access to a pc-relative access, but this is not generally true.) Code
    that runs before static PIE self relocation must avoid relying on
    dynamic relocations which can be ensured by using hidden visibility.
    However we cannot just make all symbols hidden:

    On i386, all calls to IFUNC functions must go through PLT and calls to
    hidden functions CANNOT go through PLT in PIE since EBX used in PIE PLT
    may not be set up for local calls to hidden IFUNC functions.

    This patch aims to make symbol references hidden in code that is used
    before and by _dl_relocate_static_pie when building a static PIE libc.
    Note: for an object that is used in the startup code, its references
    and definition may not have consistent visibility: it is only forced
    hidden in the startup code.

    This is needed for fixing bug 27072.

    Co-authored-by: H.J. Lu <hjl.tools@gmail.com>
    Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

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