From: Keith Owens <kaos@ocs.com.au>
To: linux-ia64@vger.kernel.org
Subject: Re: [Linux-ia64] Re: Status on ioremap patch
Date: Sat, 05 Jan 2002 23:30:46 +0000 [thread overview]
Message-ID: <marc-linux-ia64-105590698805751@msgid-missing> (raw)
In-Reply-To: <marc-linux-ia64-105590698805186@msgid-missing>
On Sat, 05 Jan 2002 16:01:29 +0100,
Steffen Persvold <sp@scali.no> wrote:
>--- linux-2.4.17/mm/memory.c.orig Fri Dec 21 18:42:05 2001
>+++ linux-2.4.17/mm/memory.c Sat Jan 5 13:13:26 2002
>@@ -791,6 +791,9 @@
> * maps a range of physical memory into the requested pages. the old
> * mappings are removed. any references to nonexistent pages results
> * in null mappings (currently treated as "copy-on-access")
>+ *
>+ * For physical (or I/O) memory mapped into the kernel virtual space,
>+ * the old mappings will not be removed.
That comment worries me. If you have multiple mappings for the same
page then you may have problems on hardware that uses virtually indexed
caches. Two virtual addresses could map to the same physical page but
index to different cache lines, destroying cache coherency. How do you
prevent that?
next prev parent reply other threads:[~2002-01-05 23:30 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-09-14 23:14 [Linux-ia64] Re: Status on ioremap patch David Mosberger
2001-09-15 12:36 ` Steffen Persvold
2001-09-28 12:39 ` Jes Sorensen
2002-01-05 15:01 ` Steffen Persvold
2002-01-05 23:30 ` Keith Owens [this message]
2002-01-06 11:02 ` Steffen Persvold
2002-01-06 11:55 ` Keith Owens
2002-01-06 14:27 ` Steffen Persvold
2002-01-09 20:01 ` Steffen Persvold
2002-01-10 3:01 ` David Mosberger
-- strict thread matches above, loose matches on Subject: below --
2004-03-03 15:12 Hugo Kohmann
2004-03-03 22:58 ` David Mosberger
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