public inbox for libc-alpha@sourceware.org
 help / color / mirror / Atom feed
From: Florian Weimer <fweimer@redhat.com>
To: "Lucas A. M. Magalhaes" <lamm@linux.ibm.com>
Cc: libc-alpha@sourceware.org
Subject: Re: [PATCH 2/3] powerpc64le: Check HWCAP bits against compiler build flags
Date: Wed, 12 May 2021 10:27:33 +0200	[thread overview]
Message-ID: <87im3owe4q.fsf@oldenburg.str.redhat.com> (raw)
In-Reply-To: <162076753769.316372.10532385586864995177@fedora.local> (Lucas A. M. Magalhaes's message of "Tue, 11 May 2021 18:12:17 -0300")

* Lucas A. M. Magalhaes:

> Hi Florian. I've tested this patch on POWER[8..10] with -mcpu=power9 and
> -mcpu=power10 built with GCC 10.3.1.
>
> When built with -mcpu=power10 I got a SIGILL on POWER8 and POWER10.

Do you mean POWER8 and POWER9?

> For testing I'm just running ./libc.so.  I try to inspect it with
> gdb. With -mcpu=power9 I can see it passing through dl_hwcap_check
> but not with -mcpu=power10.
>
> I maybe doing something wrong though.

I tried to allude in the commit message that this is expected.  Maybe I
should drop the POWER10 check?

I do not think this is fixable in the long term because I expect that
POWER10 builds won't need the bootstrap relocation in the dynamic loader
thanks to its PCREL instructions.  (POWER10 should be
PI_STATIC_AND_HIDDEN.)  We could disable POWER10 code for early parts of
the dynamic loader, but that will only work until we start to rely on
PI_STATIC_AND_HIDDEN, which has other benefits.

Thanks,
Florian


  reply	other threads:[~2021-05-12  8:27 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-06 12:30 [PATCH 0/3] Checking HWCAP bits against compiler flags Florian Weimer
2021-05-06 12:30 ` [PATCH 1/3] elf: Add hook for checking HWCAP bits after auxiliary vector parsing Florian Weimer
2021-05-12  7:43   ` Stefan Liebler
2021-05-06 12:30 ` [PATCH 2/3] powerpc64le: Check HWCAP bits against compiler build flags Florian Weimer
2021-05-11 21:12   ` Lucas A. M. Magalhaes
2021-05-12  8:27     ` Florian Weimer [this message]
2021-05-12 14:50       ` Lucas A. M. Magalhaes
2021-05-12 14:52       ` Tulio Magno Quites Machado Filho
2021-05-12 17:27         ` Florian Weimer
2021-05-12 19:24           ` Tulio Magno Quites Machado Filho
2021-05-18 16:59         ` Florian Weimer
2021-05-18 17:26           ` Tulio Magno Quites Machado Filho
2021-05-18 17:41             ` Florian Weimer
2021-05-06 12:30 ` [PATCH 3/3] s390x: Check HWCAP bits against compiler flags Florian Weimer
2021-05-12  7:43   ` Stefan Liebler

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=87im3owe4q.fsf@oldenburg.str.redhat.com \
    --to=fweimer@redhat.com \
    --cc=lamm@linux.ibm.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).