From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Akinobu Mita <mita@fixstars.com>
Cc: Arnd Bergmann <arnd@arndb.de>,
linuxppc-dev@ozlabs.org, Paul Mackerras <paulus@samba.org>,
cbe-oss-dev@ozlabs.org
Subject: Re: [patch 3/3] cell: prevent alignment interrupt on local store
Date: Wed, 11 Apr 2007 13:30:53 +1000 [thread overview]
Message-ID: <1176262253.8061.60.camel@localhost.localdomain> (raw)
In-Reply-To: <20070411025605.GB2197@localhost.localdomain>
On Wed, 2007-04-11 at 11:56 +0900, Akinobu Mita wrote:
> On Wed, Apr 11, 2007 at 07:22:48AM +1000, Benjamin Herrenschmidt wrote:
> > On Tue, 2007-04-10 at 20:15 +0900, Akinobu Mita wrote:
> > > An Alignment interrupt occurs when the instruction is lmw, stmw, lswi, lswx,
> > > stswi, or stswx, and the operand is in local store.
> > >
> > > GCC generated such instructions to handle memcpy() instead of kernel
> > > defined memcpy() without -mno-string option.
> > >
> > > Signed-off-by: Akinobu Mita <mita@fixstars.com>
> >
> > I would personally prefer building the entire kernel with -mno-string
> > when cell support is enabled...
>
> I'm about to resend the patch which prevent alignment interrupts on LS
> by using memcpy_fromio() rather than putting a collection of -mno-* options
> in Makefile. (only -mno-string is not enough to prevent that as Segher said)
Sure, however we also know for sure that string instructions will suck a
LOT on a cell ... so for a multi platforms kernel that has cell support
built-in, it makes some sense to not use them.
Ben.
next prev parent reply other threads:[~2007-04-11 3:30 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-04-10 11:15 [patch 3/3] cell: prevent alignment interrupt on local store Akinobu Mita
2007-04-10 12:52 ` Segher Boessenkool
2007-04-11 3:06 ` Akinobu Mita
2007-04-10 21:22 ` Benjamin Herrenschmidt
2007-04-11 2:56 ` Akinobu Mita
2007-04-11 3:30 ` Benjamin Herrenschmidt [this message]
2007-04-11 21:03 ` Segher Boessenkool
2007-04-12 4:23 ` Olaf Hering
2007-04-12 5:26 ` Benjamin Herrenschmidt
2007-04-12 6:33 ` Olaf Hering
2007-04-12 6:38 ` Benjamin Herrenschmidt
2007-04-12 8:31 ` Gabriel Paubert
2007-04-12 8:48 ` Benjamin Herrenschmidt
2007-04-12 6:50 ` Segher Boessenkool
2007-04-12 6:57 ` [Cbe-oss-dev] " Michael Ellerman
2007-04-12 7:07 ` Segher Boessenkool
2007-04-12 18:43 ` Arnd Bergmann
2007-04-12 18:55 ` Arnd Bergmann
2007-04-12 19:57 ` Segher Boessenkool
2007-04-12 19:52 ` Segher Boessenkool
2007-04-12 13:01 ` [RFC, PATCH] selection of CPU optimization Arnd Bergmann
2007-04-12 16:45 ` Kumar Gala
2007-04-12 17:26 ` [Cbe-oss-dev] " Arnd Bergmann
2007-04-12 18:17 ` Kumar Gala
2007-04-12 19:25 ` Arnd Bergmann
2007-04-12 20:04 ` Olof Johansson
2007-04-12 20:01 ` Segher Boessenkool
2007-04-12 20:22 ` Olof Johansson
2007-04-12 20:22 ` Segher Boessenkool
2007-04-12 19:50 ` Segher Boessenkool
2007-04-13 0:10 ` Arnd Bergmann
2007-04-13 2:03 ` Olof Johansson
2007-04-13 18:43 ` Segher Boessenkool
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