From: Gabriel Paubert <paubert@iram.es>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Juergen Kienhoefer <juergen@kienhoefer.com>,
linuxppc-dev list <linuxppc-dev@lists.linuxppc.org>
Subject: Re: cache coherence problem
Date: Tue, 18 Nov 2003 10:37:11 +0100 [thread overview]
Message-ID: <20031118093711.GB3924@iram.es> (raw)
In-Reply-To: <1069122238.7168.63.camel@gaston>
On Tue, Nov 18, 2003 at 02:02:28PM +1100, Benjamin Herrenschmidt wrote:
>
> On Tue, 2003-11-18 at 12:16, Juergen Kienhoefer wrote:
> > Guys,
> > Look at the folloging test program. It mmaps memory, puts some
> > instructions in it and executes it.
> > Sometimes it works, sometimes it crashes with illegal instruction.
> > This smells like cache problems.
> > Should the kernel clean the instruction cache for these addresses
> > in mmap system call?
> > Thanks for any thoughts!
> > Juergen
>
> It's your duty to ensure cache coherency. Actually, the kernel
> will eventually clean the icache for newly mapped in blank pages,
If you mean zeroed pages for blanked, I believe that it is wrong.
The reason being that 0 is an invalid instruction so that the code
would trap in any case.
Maybe I'm wrong, but I seem to remember this as an optimization
that Paulus implemented some time ago.
Gabriel
** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/
next prev parent reply other threads:[~2003-11-18 9:37 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-11-18 1:16 cache coherence problem Juergen Kienhoefer
2003-11-18 2:36 ` Matt Porter
2003-11-18 2:38 ` Michael R. Zucca
2003-11-19 22:35 ` linas
2003-11-18 3:02 ` Benjamin Herrenschmidt
2003-11-18 5:00 ` Juergen Kienhoefer
2003-11-18 5:22 ` Benjamin Herrenschmidt
2003-11-18 5:24 ` Benjamin Herrenschmidt
2003-11-18 17:40 ` cache coherence problem: FIXED Juergen Kienhoefer
2003-11-18 8:04 ` cache coherence problem Wolfgang Denk
2003-11-18 9:37 ` Gabriel Paubert [this message]
2003-11-19 0:35 ` Benjamin Herrenschmidt
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