From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mailhub1.si.c-s.fr (pegase1.c-s.fr [93.17.236.30]) by ozlabs.org (Postfix) with ESMTP id 524B72C008F for ; Sat, 7 Dec 2013 21:03:59 +1100 (EST) Message-ID: <52A2ECE4.3050407@c-s.fr> Date: Sat, 07 Dec 2013 10:39:48 +0100 From: christophe leroy MIME-Version: 1.0 To: Scott Wood Subject: Re: [PATCH] powerpc 8xx: Loading kernels over 8Mbytes without CONFIG_PIN_TLB References: <20131127110406.6DC8E1A504F@localhost.localdomain> <1386356996.7375.120.camel@snotra.buserror.net> In-Reply-To: <1386356996.7375.120.camel@snotra.buserror.net> Content-Type: text/plain; charset=UTF-8; format=flowed Cc: linuxppc-dev@lists.ozlabs.org, Paul Mackerras , linux-kernel@vger.kernel.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Le 06/12/2013 20:09, Scott Wood a écrit : > On Wed, 2013-11-27 at 12:04 +0100, Christophe Leroy wrote: >> Today, the only way to load kernels whose size is greater than 8Mbytes is to >> activate CONFIG_PIN_TLB. Otherwise, the physical memory initially mapped is >> limited to 8Mbytes. This patch sets up 24 Mbytes of initial memory regardless >> of whether CONFIG_PIN_TLB is active or not. It allows to load "big" kernels >> (for instance when activating CONFIG_LOCKDEP_SUPPORT) without having >> to activate CONFIG_PIN_TLB. > So, what happens on boards with less than 24M memory present? Even if > you avoid explicitly referencing those addresses, what if there is a > speculative access -- or does 8xx not do that? > > -Scott > Function setup_initial_memory_limit() in mm/init_32.c defines the limits based on the parameters given by the bootloader. As far as I know, the 8xx doesn't do speculative access just because an area is loaded in a TLB Entry. Christophe --- Ce courrier électronique ne contient aucun virus ou logiciel malveillant parce que la protection avast! Antivirus est active. http://www.avast.com