Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756639AbaAFW2F (ORCPT ); Mon, 6 Jan 2014 17:28:05 -0500 Received: from bear.ext.ti.com ([192.94.94.41]:41498 "EHLO bear.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755814AbaAFW2D (ORCPT ); Mon, 6 Jan 2014 17:28:03 -0500 Message-ID: <52CB2DD2.1070005@ti.com> Date: Mon, 6 Jan 2014 17:27:30 -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: =?UTF-8?B?S3J6eXN6dG9mIEhhxYJhc2E=?= , Russell King - ARM Linux CC: Russell King , Linus Torvalds , lkml , Subject: Re: Regression (ARM) arch/arm/mm/init.c doesn't build without CONFIG_ARM_PATCH_PHYS_VIRT. References: <52CB051B.1040808@ti.com> In-Reply-To: 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 05:08 PM, Krzysztof Hałasa wrote: > Santosh Shilimkar writes: > >> I am afraid you didn't understood what the fix is if you say above. >> arm_dma_limit is broken without this fix for LPAE machines with >> memory starting 4 GB physical boundary. > > I wonder what CONFIG_ARM_PATCH_PHYS_VIRT and CONFIG_ZONE_DMA do they > use? > You need to grep where the CONFIG_ARM_PATCH_PHYS_VIRT is used ;) > Of course, CONFIG_ZONE_DMA must be set, because otherwise the patch > changes a part disabled with #ifdef. CONFIG_ARM_PATCH_PHYS_VIRT must be > set because otherwise the kernel will not compile at all. > > Do you accept the fact the configurations with CONFIG_ZONE_DMA and > without CONFIG_ARM_PATCH_PHYS_VIRT are now broken - by this very commit? > > Now, what "fix" does this commit in its entirety do: > > - arm_dma_limit = PHYS_OFFSET + arm_dma_zone_size - 1; > + arm_dma_limit = __pv_phys_offset + arm_dma_zone_size - 1; > > if under the above circumstances (CONFIG_*) in > arch/arm/include/asm/memory.h we have: > > extern u64 __pv_phys_offset; > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the only usable declaration of this variable > extern u64 __pv_offset; > extern void fixup_pv_table(const void *, unsigned long); > extern const void *__pv_table_begin, *__pv_table_end; > > #define PHYS_OFFSET __pv_phys_offset > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > Your grep actually missed the assembly files where the actual patching happens. Please have a look at "arch/arm/kernel/head.S" The "CONFIG_ARM_PATCH_PHYS_VIRT" is always enabled on almost all ARM builds since its needed for multi-config kernel to work. May be its time to make it default enabled but I let Russell comment if there is any better way to handle this. 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/