From: Szabolcs Nagy <szabolcs.nagy@arm.com>
To: "H.J. Lu" <hjl.tools@gmail.com>
Cc: Adhemerval Zanella <adhemerval.zanella@linaro.org>,
GNU C Library <libc-alpha@sourceware.org>
Subject: Re: [PATCH v4 08/10] csu: Move static pie self relocation later [BZ #27072]
Date: Tue, 19 Jan 2021 17:03:20 +0000 [thread overview]
Message-ID: <20210119170319.GC3445@arm.com> (raw)
In-Reply-To: <CAMe9rOr5EyR23sqU9WnKcXYkDNe2tsx9OPqqce=qB3Ga6hctYw@mail.gmail.com>
The 01/19/2021 08:47, H.J. Lu wrote:
> On Tue, Jan 19, 2021 at 7:32 AM H.J. Lu <hjl.tools@gmail.com> wrote:
> > On Tue, Jan 19, 2021 at 7:24 AM Szabolcs Nagy <szabolcs.nagy@arm.com> wrote:
> > > The 01/19/2021 06:48, H.J. Lu wrote:
> > > > On Tue, Jan 19, 2021 at 6:37 AM Adhemerval Zanella via Libc-alpha
> > > > <libc-alpha@sourceware.org> wrote:
> > > > > On 19/01/2021 11:35, Szabolcs Nagy wrote:
> > > > > > the problem is that _dl_phdr is used in ARCH_SETUP_TLS
> > > > > > (to get the tls program headers) so the __ehdr_start
> > > > > > magic should be before that (this only matters if auxv
> > > > > > lacks AT_PHDR for some reason, which should not happen
> > > > > > normally on linux, so testing won't show the problem)
> > > > >
> > > > > By normally do you mean it might happen on a specific kernel version
> > > > > or is it architecture specific?
> > >
> > > i guess __ehdr_start symbol can be useful and with it
> > > glibc does not have to depend on auxv (which an elf
> > > loader like valgrind/qemu-user may get wrong)
> > >
> > > however it is only used as a fallback and on linux
> > > AT_PHDR is always expected to be present. (i don't
> > > know if this ever triggers)
> >
> > Only used on Hurd?
>
> Does arm64 linker always define __ehdr_start? If yes, can you drop
> "weak," to see if RELATIVE goes away?
__ehdr_start support was added in binutils 2.23
so i guess all supported binutils has it which
means we can make it non-weak indeed.
good idea.
(we can also ignore auxv and rely on __ehdr_start only,
but for now just making it non-weak should be fine.)
next prev parent reply other threads:[~2021-01-19 17:03 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-18 16:22 [PATCH v4 00/10] fix ifunc with static pie " Szabolcs Nagy
2021-01-18 16:23 ` [PATCH v4 01/10] configure: Require PI_STATIC_AND_HIDDEN for static pie Szabolcs Nagy
2021-01-18 16:23 ` [PATCH v4 02/10] libmvec: Add extra-test-objs to test-extras Szabolcs Nagy
2021-01-18 20:04 ` Adhemerval Zanella
2021-01-18 16:23 ` [PATCH v4 03/10] elf: Make the tunable struct definition internal only Szabolcs Nagy
2021-01-18 16:24 ` [PATCH v4 04/10] elf: Avoid RELATIVE relocs in __tunables_init Szabolcs Nagy
2021-01-18 16:24 ` [PATCH v4 05/10] Use hidden visibility for early static PIE code Szabolcs Nagy
2021-01-18 21:49 ` Adhemerval Zanella
2021-01-18 16:24 ` [PATCH v4 06/10] elf: Avoid RELATIVE relocation for _dl_sysinfo Szabolcs Nagy
2021-01-19 13:51 ` Adhemerval Zanella
2021-01-19 14:25 ` V2 " H.J. Lu
2021-01-19 14:35 ` Adhemerval Zanella
2021-01-18 16:25 ` [PATCH v4 07/10] Use <startup.h> in __libc_init_secure Szabolcs Nagy
2021-01-19 13:56 ` Adhemerval Zanella
2021-01-18 16:25 ` [PATCH v4 08/10] csu: Move static pie self relocation later [BZ #27072] Szabolcs Nagy
2021-01-19 14:07 ` Adhemerval Zanella
2021-01-19 14:35 ` Szabolcs Nagy
2021-01-19 14:36 ` Adhemerval Zanella
2021-01-19 14:48 ` H.J. Lu
2021-01-19 15:24 ` Szabolcs Nagy
2021-01-19 15:32 ` H.J. Lu
2021-01-19 16:47 ` H.J. Lu
2021-01-19 17:03 ` Szabolcs Nagy [this message]
2021-01-19 17:10 ` H.J. Lu
2021-01-19 17:25 ` Fāng-ruì Sòng
2021-01-19 17:33 ` H.J. Lu
2021-01-19 17:38 ` Fāng-ruì Sòng
2021-01-19 17:38 ` Szabolcs Nagy
2021-01-19 17:42 ` H.J. Lu
2021-01-19 17:47 ` Szabolcs Nagy
2021-01-19 17:53 ` H.J. Lu
2021-01-19 17:59 ` H.J. Lu
2021-01-18 16:25 ` [PATCH v4 09/10] x86: Check ifunc resolver with CPU_FEATURE_USABLE " Szabolcs Nagy
2021-01-19 14:11 ` Adhemerval Zanella
2021-01-19 14:37 ` V2 " H.J. Lu
2021-01-21 16:33 ` H.J. Lu
2021-01-18 16:26 ` [PATCH v4 10/10] Make libc symbols hidden in static PIE Szabolcs Nagy
2021-01-18 21:37 ` [PATCH v4 00/10] fix ifunc with static pie [BZ #27072] Adhemerval Zanella
2021-01-19 18:25 ` Szabolcs Nagy
2021-01-19 19:41 ` H.J. Lu
2021-01-19 20:16 ` Adhemerval Zanella
2021-01-19 21:38 ` H.J. Lu
2021-01-20 11:29 ` Adhemerval Zanella
2021-01-20 12:38 ` Szabolcs Nagy
2021-01-20 12:49 ` H.J. Lu
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210119170319.GC3445@arm.com \
--to=szabolcs.nagy@arm.com \
--cc=adhemerval.zanella@linaro.org \
--cc=hjl.tools@gmail.com \
--cc=libc-alpha@sourceware.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).