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 3A657DDDF0 for ; Tue, 11 Nov 2008 13:22:14 +1100 (EST) Subject: Re: [RFC PATCH] Support for big page sizes on 44x (Updated) From: Benjamin Herrenschmidt To: Ilya Yanok In-Reply-To: <1226369868.7530.60.camel@pasglop> References: <1224123753-20907-1-git-send-email-yanok@emcraft.com> <1226369868.7530.60.camel@pasglop> Content-Type: text/plain Date: Tue, 11 Nov 2008 13:22:03 +1100 Message-Id: <1226370123.7530.61.camel@pasglop> Mime-Version: 1.0 Cc: linuxppc-dev@ozlabs.org, pvr@emcraft.com, dzu@denx.de, wd@denx.de List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , > Well, the main thing is the implementation of kmap and kmap_atomic. > > They both basically assumes that all the reserved PTEs for kmap and > kmap_atomic are in a single PTE page since it uses a simple addition > (substraction for _atomic really but heh, that's about the same). > > Note that PKMAP (kmap) and FIXMAP (kmap_atomic) can be in two different > PTE pages. But it's important that the whole PKMAP is entirely contained > within a PTE page. It doesn't have to -start- on a PTE page boundary > though. Also note that if you end up with PKMAP and FIXMAP on two different PTE pages, make sure they are both instanciated at boot time. Ben.