Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752244AbbBWMQh (ORCPT ); Mon, 23 Feb 2015 07:16:37 -0500 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:44334 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752120AbbBWMQg (ORCPT ); Mon, 23 Feb 2015 07:16:36 -0500 Date: Mon, 23 Feb 2015 13:13:55 +0100 From: Pavel Machek To: Rob Herring Cc: Dinh Nguyen , Dinh Nguyen , Arnd Bergmann , "linux-kernel@vger.kernel.org" , Olof Johansson , Russell King - ARM Linux , "linux-arm-kernel@lists.infradead.org" Subject: Re: [RESEND PATCH 2/2] arm: socfpga: Set share override bit of the l2 cache controller Message-ID: <20150223121355.GA29491@Nokia-N900> References: <1424365606-19964-1-git-send-email-dinguyen@opensource.altera.com> <1424365606-19964-2-git-send-email-dinguyen@opensource.altera.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2135 Lines: 53 On Thu 2015-02-19 12:13:13, Rob Herring wrote: > On Thu, Feb 19, 2015 at 11:06 AM, wrote: > > From: Dinh Nguyen > > > > By not having bit 22 set in the PL310 Auxiliary Control register (shared > > attribute override enable) has the side effect of transforming Normal > > Shared Non-cacheable reads into Cacheable no-allocate reads. > > > > Coherent DMA buffers in Linux always have a Cacheable alias via the > > kernel linear mapping and the processor can speculatively load cache > > lines into the PL310 controller. With bit 22 cleared, Non-cacheable > > reads would unexpectedly hit such cache lines leading to buffer > > corruption. > > You really should be doing this in your bootloader. > You mean... in all your bootloaders? Because there's more than one. And as both bootloaders need it, it makes sense to do it in kernel, afaict. Pavel > > DT_MACHINE_START(SOCFPGA, "Altera SOCFPGA") > > .l2c_aux_val = L310_AUX_CTRL_DATA_PREFETCH | > > - L310_AUX_CTRL_INSTR_PREFETCH, > > + L310_AUX_CTRL_INSTR_PREFETCH | > > + L2C_AUX_CTRL_SHARED_OVERRIDE, > > .l2c_aux_mask = ~0, > > .smp = smp_ops(socfpga_smp_ops), > > .map_io = socfpga_map_io, > > -- > > 2.2.1 > > > > > > _______________________________________________ > > linux-arm-kernel mailing list > > linux-arm-kernel@lists.infradead.org > > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/