From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-lf1-x135.google.com ([2a00:1450:4864:20::135]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1gpBnc-0008Gz-TC for barebox@lists.infradead.org; Thu, 31 Jan 2019 12:50:35 +0000 Received: by mail-lf1-x135.google.com with SMTP id z13so2197234lfe.11 for ; Thu, 31 Jan 2019 04:50:32 -0800 (PST) Date: Thu, 31 Jan 2019 15:50:28 +0300 From: Peter Mamonov Message-ID: <20190131125028.glbnt55zmhqowi6p@localhost.localdomain> References: <20190129065549.29161-1-andrew.smirnov@gmail.com> <20190129065549.29161-19-andrew.smirnov@gmail.com> <20190129084847.spkfbeksb7xne46g@pengutronix.de> <20190131105452.smetw36klsxmvtaq@localhost.localdomain> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190131105452.smetw36klsxmvtaq@localhost.localdomain> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: Re: [PATCH v2 18/19] drivers: mem: Create file to access second half of 64-bit memory To: Andrey Smirnov Cc: Barebox List On Thu, Jan 31, 2019 at 01:54:52PM +0300, Peter Mamonov wrote: > Hello, Andrey, > > > In order to allow access to second half of address space on 64-bit > > machines, add code that creates /dev/highmem dedicated for that. > > > > Note that due to maximum file size being limited to MAX_LFS_FILESIZE > > or 0x7fff_ffff_ffff_ffff bytes at addresses 0x7fff_ffff_ffff_ffff and > > 0xffff_ffff_ffff_ffff cannot be access through /dev/mem and > > /dev/hightmem correspondingly. > > Does it imply using `-s /dev/highmem` argument when accessing addresses beyond > MAX_LFS_FILESIZE? That's not very convenient: > > $ git grep -l /dev/mem > commands/crc.c > commands/digest.c > commands/disasm.c > commands/md.c > commands/memcmp.c > commands/memcpy.c > commands/memset.c > commands/mm.c > commands/mw.c I've forgotten to mention, that all meaningful MIPS64 virtual addresses belong to the 2nd half of the address space. Except for user segment addresses which are not used in barebox. > > Regards, > Peter _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox