From: Benjamin Herrenschmidt <bh40@calva.net>
To: linuxppc-dev@lists.linuxppc.org, Paul Mackerras <paulus@cs.anu.edu.au>
Subject: Problem with iMacs and kernel entry
Date: Mon, 15 Feb 1999 13:41:04 +0100 [thread overview]
Message-ID: <19990215134104.006599@mail.mipsys.com> (raw)
I've just thought about another problem:
Since the new bootx will enter the kernel with MMU disabled, no-one is
allowed to perform any kind of i/o until the MMU is re-enabled. At least
that's my understanding, since cache and speculative pre-fetching are
enabled for the whole address range, including devices.
That means that the iMac "hack" in prom.c that disables the USB
controller will get into trouble, won't it ?
I want to avoid enabling the MMU in the bootstrap to avoid the problem of
TLB misses on 603 (the boostrap has no exception handler) and I don't
like the fact that the kernel entry plays with BATs with MMU enabled.
Any comments ?
--
E-Mail: <mailto:bh40@calva.net>
BenH. Web : <http://calvaweb.calvacom.fr/bh40/>
[[ This message was sent via the linuxppc-dev mailing list. Replies are ]]
[[ not forced back to the list, so be sure to Cc linuxppc-dev if your ]]
[[ reply is of general interest. To unsubscribe from linuxppc-dev, send ]]
[[ the message 'unsubscribe' to linuxppc-dev-request@lists.linuxppc.org ]]
next reply other threads:[~1999-02-15 12:41 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
1999-02-15 12:41 Benjamin Herrenschmidt [this message]
1999-02-15 15:55 ` Problem with iMacs and kernel entry Gabriel Paubert
1999-02-15 16:48 ` Benjamin Herrenschmidt
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=19990215134104.006599@mail.mipsys.com \
--to=bh40@calva.net \
--cc=linuxppc-dev@lists.linuxppc.org \
--cc=paulus@cs.anu.edu.au \
/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).