From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 25 Aug 2000 11:40:38 -0500 From: Timur Tabi In-Reply-To: References: <20000825153600Z131177-250+6@kanga.kvack.org> Subject: Re: pgd/pmd/pte and x86 kernel virtual addresses Message-Id: <20000825165116Z131177-250+7@kanga.kvack.org> Sender: owner-linux-mm@kvack.org Return-Path: To: Linux MM mailing list List-ID: ** Reply to message from "Benjamin C.R. LaHaise" on Fri, 25 Aug 2000 12:45:18 -0400 (EDT) > > What I'm trying to do is allocate some memory via get_free_pages, and then mark > > that memory as uncacheable. > > ioremap_nocache should be able to do what you want. Well, that's what I tried to explain in my previous email which people seem to be ignoring. I tried ioremap_nocache, and it doesn't appear to be working. There are a number of problems: 1) I'm trying to mark regular RAM as uncacheable, and ioremap_nocache() requires me to munge the PG_Reservered bit for each page before I can do that. Ugly. 2) ioremap_nocache() allocates virtual RAM. I already have a virtual address, I don't need another one. 3) The unmap function for ioremap_nocache() is a no-op. So after I remap and mark the page as uncacheable, there's no way to restore it after I'm done! 4) Even with all this, it appears that the function isn't working. I've attached a logical analyzer to the memory bus, and writes are not being sent out, leading me to believe the memory is still being cached. -- Timur Tabi - ttabi@interactivesi.com Interactive Silicon - http://www.interactivesi.com When replying to a mailing-list message, please don't cc: me, because then I'll just get two copies of the same message. -- 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/