From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mircea Gherzan Subject: Re: [PATCH v2] ARM: net: JIT compiler for packet filters Date: Mon, 19 Dec 2011 19:14:01 +0200 Message-ID: <20111219171401.GA1732@swarm.cs.pub.ro> References: <1324284030-25540-1-git-send-email-mgherzan@gmail.com> <20111219125021.GA2031@linaro.org> <20111219151958.GU24496@pengutronix.de> <20111219152418.GF2031@linaro.org> <20111219153338.GV24496@pengutronix.de> <20111219155252.GG2031@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-arm-kernel@lists.infradead.org, netdev@vger.kernel.org To: Dave Martin Return-path: Received: from mail-ee0-f46.google.com ([74.125.83.46]:58100 "EHLO mail-ee0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751497Ab1LSROK (ORCPT ); Mon, 19 Dec 2011 12:14:10 -0500 Received: by eekc4 with SMTP id c4so5645288eek.19 for ; Mon, 19 Dec 2011 09:14:09 -0800 (PST) Content-Disposition: inline In-Reply-To: <20111219155252.GG2031@linaro.org> Sender: netdev-owner@vger.kernel.org List-ID: Hi, On Mon, Dec 19, 2011 at 03:52:52PM +0000, Dave Martin wrote: > On Mon, Dec 19, 2011 at 04:33:38PM +0100, Uwe Kleine-K?nig wrote: > > Hello, > > > > On Mon, Dec 19, 2011 at 03:24:18PM +0000, Dave Martin wrote: > > > On Mon, Dec 19, 2011 at 04:19:58PM +0100, Uwe Kleine-K?nig wrote: > > > > On Mon, Dec 19, 2011 at 12:50:21PM +0000, Dave Martin wrote: > > > > > On Mon, Dec 19, 2011 at 09:40:30AM +0100, Mircea Gherzan wrote: > > > > > > Based of Matt Evans's PPC64 implementation. > > > > > Note that it's fine to have the JIT generating ARM code, even if the rest > > > > > if the kernel is Thumb-2. This would only start to cause problems if we > > > > > want to do things like set kprobes in the JITted code, or unwind out of > > > > > the JITted code. > > > > or use a CPU that doesn't speak ARM (e.g. v7M) > > > > > > Indeed... I was assuming though that that would be out of scope for the > > > first iteration of this code. > > Right, depending on !THUMB2 is fine. Only generating ARM code with > > THUMB2=y is not. > > The kernel doesn't support v7-M upstream though. CONFIG_THUMB2_KERNEL=y > doesn't mean that there is no ARM code present -- there _is_ ARM code in > the kernel image even with this option (though not very much). What about relying at runtime on bits[3:0] of ID_PFR0? And this only for ARMv7. Are there any other ARM cores of interest that do _not_ support the ARM instruction set? Thanks, Mircea