All of lore.kernel.org
 help / color / mirror / Atom feed
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 ]]

             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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.