From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760230AbZEFPJ2 (ORCPT ); Wed, 6 May 2009 11:09:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756696AbZEFPJQ (ORCPT ); Wed, 6 May 2009 11:09:16 -0400 Received: from hera.kernel.org ([140.211.167.34]:35775 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756543AbZEFPJN (ORCPT ); Wed, 6 May 2009 11:09:13 -0400 Message-ID: <4A01A784.2050407@kernel.org> Date: Wed, 06 May 2009 08:06:44 -0700 From: Yinghai Lu User-Agent: Thunderbird 2.0.0.19 (X11/20081227) MIME-Version: 1.0 To: Ingo Molnar CC: Jesse Barnes , Ivan Kokshaysky , Linus Torvalds , "H. Peter Anvin" , Andrew Morton , Thomas Gleixner , "linux-kernel@vger.kernel.org" , linux-pci@vger.kernel.org, yannick.roehlly@free.fr Subject: [PATCH 1/2] x86: reserve range near the ram References: <49EF9C10.6090107@kernel.org> <20090422154900.08f8f366@hobbes> <49EFBB0E.3030401@kernel.org> <20090422180505.2518e837@hobbes> <49EFCE15.3030605@kernel.org> <20090423132202.GB13984@jurassic.park.msu.ru> <49F08580.9050407@kernel.org> <20090423221936.GA24171@jurassic.park.msu.ru> <49F13690.3080902@kernel.org> <20090505115248.63d112f4@hobbes> <20090506123346.GA19541@elte.hu> In-Reply-To: <20090506123346.GA19541@elte.hu> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Linus Torvalds The point is to take all RAM resources we have, and _after_ we've added all the resources we've seen in the E820 tree, we then _also_ try to add fake reserved entries for any "round up to X" at the end of the RAM resources. [ Impact: protect stolen RAM ] Acked-by: Jesse Barnes Signed-off-by: Yinghai Lu --- arch/x86/kernel/e820.c | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) Index: linux-2.6/arch/x86/kernel/e820.c =================================================================== --- linux-2.6.orig/arch/x86/kernel/e820.c +++ linux-2.6/arch/x86/kernel/e820.c @@ -1370,6 +1370,23 @@ void __init e820_reserve_resources(void) } } +/* How much should we pad RAM ending depending on where it is? */ +static unsigned long ram_alignment(resource_size_t pos) +{ + unsigned long mb = pos >> 20; + + /* To 64kB in the first megabyte */ + if (!mb) + return 64*1024; + + /* To 1MB in the first 16MB */ + if (mb < 16) + return 1024*1024; + + /* To 32MB for anything above that */ + return 32*1024*1024; +} + void __init e820_reserve_resources_late(void) { int i; @@ -1381,6 +1398,24 @@ void __init e820_reserve_resources_late( insert_resource_expand_to_fit(&iomem_resource, res); res++; } + + /* + * Try to bump up RAM regions to reasonable boundaries to + * avoid stolen RAM + */ + for (i = 0; i < e820.nr_map; i++) { + struct e820entry *entry = &e820_saved.map[i]; + resource_size_t start, end; + + if (entry->type != E820_RAM) + continue; + start = entry->addr + entry->size; + end = round_up(start, ram_alignment(start)); + if (start == end) + continue; + reserve_region_with_split(&iomem_resource, start, + end - 1, "RAM buffer"); + } } char *__init default_machine_specific_memory_setup(void)