From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 25 Jan 2001 15:16:55 +0000 From: "Stephen C. Tweedie" Subject: Re: ioremap_nocache problem? Message-ID: <20010125151655.V11607@redhat.com> References: <3A6D5D28.C132D416@sangate.com> <20010123165117Z131182-221+34@kanga.kvack.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20010123165117Z131182-221+34@kanga.kvack.org>; from ttabi@interactivesi.com on Tue, Jan 23, 2001 at 10:53:51AM -0600 Sender: owner-linux-mm@kvack.org Return-Path: To: Timur Tabi Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org List-ID: Hi, On Tue, Jan 23, 2001 at 10:53:51AM -0600, Timur Tabi wrote: > > My problem is that it's very easy to map memory with ioremap_nocache, but if > you use iounmap() the un-map it, the entire system will crash. No one has been > able to explain that one to me, either. ioremap*() is only supposed to be used on IO regions or reserved pages. If you haven't marked the pages as reserved, then iounmap will do the wrong thing, so it's up to you to reserve the pages. Cheers, Stephen -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux.eu.org/Linux-MM/