Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753481AbaAGRqY (ORCPT ); Tue, 7 Jan 2014 12:46:24 -0500 Received: from devils.ext.ti.com ([198.47.26.153]:51900 "EHLO devils.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751963AbaAGRqQ (ORCPT ); Tue, 7 Jan 2014 12:46:16 -0500 Message-ID: <52CC3D46.3090102@ti.com> Date: Tue, 7 Jan 2014 12:45:42 -0500 From: Santosh Shilimkar User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/17.0 Thunderbird/17.0 MIME-Version: 1.0 To: Russell King - ARM Linux CC: =?UTF-8?B?S3J6eXN6dG9mIEhhxYJhc2E=?= , Linus Torvalds , lkml , "linux-arm-kernel@lists.infradead.org" Subject: Re: Regression (ARM) arch/arm/mm/init.c doesn't build without CONFIG_ARM_PATCH_PHYS_VIRT. References: <20140106223906.GH27432@n2100.arm.linux.org.uk> <52CB3F55.1050404@ti.com> <20140107011121.GI27432@n2100.arm.linux.org.uk> In-Reply-To: <20140107011121.GI27432@n2100.arm.linux.org.uk> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Monday 06 January 2014 08:11 PM, Russell King - ARM Linux wrote: > On Mon, Jan 06, 2014 at 06:42:13PM -0500, Santosh Shilimkar wrote: >> On Monday 06 January 2014 05:39 PM, Russell King - ARM Linux wrote: >>> On Mon, Jan 06, 2014 at 08:28:20PM +0100, Krzysztof Hałasa wrote: >>>> Russell, Santosh, >>>> >>>> the unneeded commit causing regression is still in place. Please try to >>>> compile an ARM kernel without CONFIG_ARM_PATCH_PHYS_VIRT and with >>>> CONFIG_ZONE_DMA and see for yourself, if you don't believe me. >>>> >>>> Please be aware that this commit fixes nothing, its only function is >>>> causing the regression - so we don't lose anything by reverting it. >>>> >>>> If the attached wasn't clear, what the defective commit presently does >>>> is changing a perfectly valid code into a code referencing a variable >>>> which (without CONFIG_ARM_PATCH_PHYS_VIRT set) doesn't at all exist. >>>> >>>> With CONFIG_ARM_PATCH_PHYS_VIRT set, this commit does precisely nothing. >>> > > /-------------------------------------------------------------- > | > > Right, so, with Assabet, which has CONFIG_DMA_ZONE=y and > | > > CONFIG_ARM_PATCH_PHYS_VIRT=y: > | > > > | > > $ make O=../build/assabet arch/arm/mm/init.i > | > > > | > > gives: > | > > arm_dma_limit = __pv_phys_offset + arm_dma_zone_size - 1; > | > > > | > > with or without Santosh's patch. > \-------------------------------------------------------------- > >> May be I missed your point but I ended up creating the patch because >> the CMA reservation was failing on Keystone since the arm_dma_limit >> wasn't right since it wasn't considering the actual __pv_phys_offset. >> >> Isn't that an issue ? > > See the above. Your patch has _no_ effect what so ever when > CONFIG_ARM_PATCH_PHYS_VIRT=y - which you have on the Keystone, right? > > If you don't believe me, ask make to produce arch/arm/mm/init.i, which > is the output from the preprocessor, comparing the resulting generated > file both with and without your patch applied. > Looks like you are right. I did two fixes to have right arm_dma_limit in below order. 1. 787b0d5 {ARM: 7908/1: mm: Fix the arm_dma_limit calculation} 2. 7c92732 {ARM: 7909/1: mm: Call setup_dma_zone() post early_paging_init()} But with 2 alone the issue gets fixed since with ARM_PATCH_PHYS_VIRT and below pre-processor, the PHYS_OFFSET also gets an updated value. I never realised that 1 becomes redundant after second patch while creating them. #define PHYS_OFFSET __pv_phys_offset So indeed, 787b0d5{ARM: 7908/1: mm: Fix the arm_dma_limit calculation} won't be needed anymore and can be reverted. Sorry it took some time for me to reach to your conclusion. Regards, Santosh -- 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/