mailing list of musl libc
 help / color / mirror / code / Atom feed
From: Florian Weimer <fweimer@redhat.com>
To: Stijn Tintel <stijn@linux-ipv6.be>
Cc: musl@lists.openwall.com
Subject: Re: [musl] [PATCH] ppc64: check for AltiVec in setjmp/longjmp
Date: Tue, 07 Dec 2021 01:37:12 +0100	[thread overview]
Message-ID: <87tufljlmv.fsf@oldenburg.str.redhat.com> (raw)
In-Reply-To: <20211206234358.2174444-1-stijn@linux-ipv6.be> (Stijn Tintel's message of "Tue, 7 Dec 2021 01:43:58 +0200")

* Stijn Tintel:

> diff --git a/src/setjmp/powerpc64/setjmp.s b/src/setjmp/powerpc64/setjmp.s
> index 37683fda..32853693 100644
> --- a/src/setjmp/powerpc64/setjmp.s
> +++ b/src/setjmp/powerpc64/setjmp.s
> @@ -69,7 +69,17 @@ __setjmp_toc:
>  	stfd 30, 38*8(3)
>  	stfd 31, 39*8(3)
>  
> -	# 5) store vector registers v20-v31
> +	# 5) store vector registers v20-v31 if hardware supports AltiVec
> +	mflr 0
> +	bl 1f
> +	.hidden __hwcap
> +	.long __hwcap-.
> +1:	mflr 4

This de-balances the return stack and probably has quite severe
performance impact.  The ISA manual says to use

  bcl 20,31,$+4

and you'll have to store the __hwcap offset somewhere else.

Thanks,
Florian


  reply	other threads:[~2021-12-07  0:37 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-06 23:43 Stijn Tintel
2021-12-07  0:37 ` Florian Weimer [this message]
2021-12-07  0:59   ` Rich Felker
2021-12-07  1:15     ` David Edelsohn
2021-12-07  1:39       ` Rich Felker
2021-12-07  1:44         ` David Edelsohn
2021-12-07 13:25           ` Rich Felker
2021-12-07 13:39             ` David Edelsohn
2021-12-07 14:43               ` Rich Felker
2021-12-07 14:48                 ` David Edelsohn
2021-12-07 18:39             ` Markus Wichmann
2021-12-07 18:57               ` David Edelsohn
2021-12-07 19:28               ` Florian Weimer
2021-12-07 20:15                 ` Markus Wichmann
2021-12-07 20:29                   ` Rich Felker
2021-12-08  5:02                     ` Markus Wichmann
2021-12-07 18:27           ` James Y Knight
2021-12-07 18:57             ` Markus Wichmann
2021-12-08  8:43     ` Stijn Tintel
2021-12-08 13:37       ` Rich Felker
2021-12-08 15:36         ` Rich Felker

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=87tufljlmv.fsf@oldenburg.str.redhat.com \
    --to=fweimer@redhat.com \
    --cc=musl@lists.openwall.com \
    --cc=stijn@linux-ipv6.be \
    /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. 
Code repositories for project(s) associated with this public inbox

	https://git.vuxu.org/mirror/musl/

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 NNTP newsgroup(s).