From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756394Ab1JQQBW (ORCPT ); Mon, 17 Oct 2011 12:01:22 -0400 Received: from gate.crashing.org ([63.228.1.57]:48782 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752819Ab1JQQBV convert rfc822-to-8bit (ORCPT ); Mon, 17 Oct 2011 12:01:21 -0400 Subject: Re: [PATCH] uio: Support 36-bit physical addresses on 32-bit systems Mime-Version: 1.0 (Apple Message framework v1251.1) Content-Type: text/plain; charset=us-ascii From: Kumar Gala In-Reply-To: <20111014183144.GD28556@local> Date: Mon, 17 Oct 2011 11:00:55 -0500 Cc: linuxppc-dev@ozlabs.org, linux-kernel@vger.kernel.org, gregkh@suse.de, Kai Jiang Content-Transfer-Encoding: 8BIT Message-Id: <4D73F261-3795-4F71-9921-568C1B9F06E0@kernel.crashing.org> References: <1318521058-15662-1-git-send-email-galak@kernel.crashing.org> <20111014183144.GD28556@local> To: "Hans J. Koch" X-Mailer: Apple Mail (2.1251.1) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Oct 14, 2011, at 1:31 PM, Hans J. Koch wrote: > On Thu, Oct 13, 2011 at 10:50:58AM -0500, Kumar Gala wrote: >> From: Kai Jiang >> >> To support >32-bit physical addresses for UIO_MEM_PHYS type we need to >> extend the width of 'addr' in struct uio_mem. Numerous platforms like >> embedded PPC, ARM, and X86 have support for systems with larger physical >> address than logical. >> >> Since 'addr' may contain a physical, logical, or virtual address the >> easiest solution is to just change the type to 'phys_addr_t' which >> should always be greater than or equal to the sizeof(void *) such that >> it can properly hold any of the address types. >> >> For physical address we can support up to a 44-bit physical address on a >> typical 32-bit system as we utilize remap_pfn_range() for the mapping of >> the memory region and pfn's are represnted by shifting the address by >> the page size (typically 4k). >> >> Signed-off-by: Kai Jiang >> Signed-off-by: Minghuan Lian >> Signed-off-by: Kumar Gala > > Signed-off-by: "Hans J. Koch" > > That looks good to me. There's an unnecessary cast (see below), but I fixed that > on the way. > > Greg, please pull this from branch uio-for-gregkh from > > git://hansjkoch.de/git/linux-hjk > > Thanks, > Hans I think removing that cast is wrong: drivers/uio/uio.c: In function 'uio_vma_fault': drivers/uio/uio.c:637:26: warning: cast to pointer from integer of different size - k