From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id B7A9ADDED9 for ; Tue, 25 Mar 2008 14:31:29 +1100 (EST) Message-Id: From: Kumar Gala To: Zhang Wei In-Reply-To: <78567AC4946EDC42B7DE978C350CD869EC52AE@zch01exm26.fsl.freescale.net> Content-Type: text/plain; charset=US-ASCII; format=flowed Mime-Version: 1.0 (Apple Message framework v919.2) Subject: Re: [PATCH] [POWERPC] Introduce lowmem_end_addr to distiguish fromtotal_lowmem Date: Mon, 24 Mar 2008 22:31:16 -0500 References: <78567AC4946EDC42B7DE978C350CD869EC52AE@zch01exm26.fsl.freescale.net> Cc: linuxppc-dev@ozlabs.org, Wang Haiying List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Mar 24, 2008, at 10:18 PM, Zhang Wei wrote: > Hi, Kumar, > >> -----Original Message----- >> From: linuxppc-dev-bounces+wei.zhang=freescale.com@ozlabs.org >> >> total_lowmem represents the amount of low memory not the >> physical address >> that low memory ends at. If the start of memory is at 0 it >> happends that >> total_lowmem can be used as both the size and the address that lowmem >> ends at. (technical its one byte beyond the end) >> >> To make the code a bit more clear and deal with the case when >> the start of >> memory isn't at physical 0, we introduce lowmem_end_addr that >> represents >> one byte beyond the last physical address in the lowmem region. > > About the kernel memory offset, if the memory area from phyical 0 > to lowmem start address is reserved for other usage in this kernel, > no more comments. If it will be used by other kernel (in asmp mode), > how about to use tlb mapping physical address to virtual address 0 > not move the kernel lowmem address? I consider the tlb mapping > will be more safe. I'm not sure I follow your question. - k