From: Anton Blanchard <anton@samba.org>
To: Momchil Velikov <velco@fadata.bg>
Cc: linuxppc-dev@lists.linuxppc.org
Subject: Re: powerpc wmb()
Date: Mon, 19 Nov 2001 00:13:05 +1100 [thread overview]
Message-ID: <20011119001305.E3896@krispykreme> (raw)
In-Reply-To: <8766885j7w.fsf@fadata.bg>
Hi,
[ yes this is a better place than debian-powerpc for this sort of
conversation :) ]
> wmb is defined as
>
> #define wmb() __asm__ __volatile__ ("eieio" : : : "memory")
>
> however, ``eieio'' has no effect on memory, that is
> Write Through Not Required, thus I think it should be
>
> #define wmb() __asm__ __volatile__ ("sync" : : : "memory")
While the original ppc spec did not guarantee eieio ordered writes
to caching allowed, write through not required, memory coherence
required storage, there have been modifications since:
http://www.rs6000.ibm.com/tech/ppc-chg2.html
Look for the change "Book II, Section 3.3, page 350"
My understanding is that the earlier chips completed stores in order
which allowed the above change to be made safely, but I am not 100%
on this.
Anton
** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/
prev parent reply other threads:[~2001-11-18 13:13 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-11-18 12:58 powerpc wmb() Momchil Velikov
2001-11-18 13:13 ` Anton Blanchard [this message]
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=20011119001305.E3896@krispykreme \
--to=anton@samba.org \
--cc=linuxppc-dev@lists.linuxppc.org \
--cc=velco@fadata.bg \
/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 NNTP newsgroup(s).