Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753352AbbBSSNh (ORCPT ); Thu, 19 Feb 2015 13:13:37 -0500 Received: from mail-wi0-f182.google.com ([209.85.212.182]:35682 "EHLO mail-wi0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752913AbbBSSNf (ORCPT ); Thu, 19 Feb 2015 13:13:35 -0500 MIME-Version: 1.0 In-Reply-To: <1424365606-19964-2-git-send-email-dinguyen@opensource.altera.com> References: <1424365606-19964-1-git-send-email-dinguyen@opensource.altera.com> <1424365606-19964-2-git-send-email-dinguyen@opensource.altera.com> From: Rob Herring Date: Thu, 19 Feb 2015 12:13:13 -0600 Message-ID: Subject: Re: [RESEND PATCH 2/2] arm: socfpga: Set share override bit of the l2 cache controller To: Dinh Nguyen Cc: Russell King - ARM Linux , Dinh Nguyen , Arnd Bergmann , "linux-kernel@vger.kernel.org" , Olof Johansson , "linux-arm-kernel@lists.infradead.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1971 Lines: 50 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. Rob > > Signed-off-by: Dinh Nguyen > --- > arch/arm/mach-socfpga/socfpga.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/arch/arm/mach-socfpga/socfpga.c b/arch/arm/mach-socfpga/socfpga.c > index a5f1fda..4ce2100 100644 > --- a/arch/arm/mach-socfpga/socfpga.c > +++ b/arch/arm/mach-socfpga/socfpga.c > @@ -105,7 +105,8 @@ static const char *altera_dt_match[] = { > > 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 -- 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/