From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756246AbZCLNHQ (ORCPT ); Thu, 12 Mar 2009 09:07:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753063AbZCLNGp (ORCPT ); Thu, 12 Mar 2009 09:06:45 -0400 Received: from vpn.id2.novell.com ([195.33.99.129]:38782 "EHLO vpn.id2.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752308AbZCLNGn convert rfc822-to-8bit (ORCPT ); Thu, 12 Mar 2009 09:06:43 -0400 Message-Id: <49B9171B.76E4.0078.0@novell.com> X-Mailer: Novell GroupWise Internet Agent 8.0.0 Date: Thu, 12 Mar 2009 13:07:23 +0000 From: "Jan Beulich" To: , , Cc: Subject: [PATCH] x86: fix code paths used by update_mptable Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8BIT Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Impact: bug fix find_e820_area_size() must return a properly distinguishable and out-of-bounds value when it fails, and -1UL does not meet that criteria on i386/PAE. Additionally, callers of the function must check against that value. early_reserve_e820() should be prepared for the region found to be outside of the addressable range on 32-bits. e820_update_range_map() should not blindly update e820, but should do all it work on the map it got a pointer passed for (which in 50% of the cases is &e820_saved). It must also not call e820_add_region(), as that again acts on e820 unconditionally. The issues were found when trying to make this option work in our Xen kernel (i.e. where some of the silent assumptions made in the code would not hold). Signed-off-by: Jan Beulich --- arch/x86/kernel/check.c | 2 +- arch/x86/kernel/e820.c | 32 +++++++++++++++++++++++++------- 2 files changed, 26 insertions(+), 8 deletions(-) --- linux-2.6.29-rc7/arch/x86/kernel/check.c 2009-03-04 09:10:19.000000000 +0100 +++ 2.6.29-rc7-x86-update-mptable/arch/x86/kernel/check.c 2009-03-06 11:00:54.000000000 +0100 @@ -83,7 +83,7 @@ void __init setup_bios_corruption_check( u64 size; addr = find_e820_area_size(addr, &size, PAGE_SIZE); - if (addr == 0) + if (!(addr + 1)) break; if ((addr + size) > corruption_check_size) --- linux-2.6.29-rc7/arch/x86/kernel/e820.c 2009-03-04 09:10:19.000000000 +0100 +++ 2.6.29-rc7-x86-update-mptable/arch/x86/kernel/e820.c 2009-03-06 11:03:54.000000000 +0100 @@ -421,7 +421,7 @@ static u64 __init e820_update_range_map( u64 size, unsigned old_type, unsigned new_type) { - int i; + unsigned int i, x; u64 real_updated_size = 0; BUG_ON(old_type == new_type); @@ -429,7 +429,7 @@ static u64 __init e820_update_range_map( if (size > (ULLONG_MAX - start)) size = ULLONG_MAX - start; - for (i = 0; i < e820.nr_map; i++) { + for (i = 0; i < e820x->nr_map; i++) { struct e820entry *ei = &e820x->map[i]; u64 final_start, final_end; if (ei->type != old_type) @@ -446,14 +446,23 @@ static u64 __init e820_update_range_map( final_end = min(start + size, ei->addr + ei->size); if (final_start >= final_end) continue; - e820_add_region(final_start, final_end - final_start, - new_type); + + x = e820x->nr_map; + if (x == ARRAY_SIZE(e820x->map)) { + printk(KERN_ERR "Too many memory map entries!\n"); + break; + } + e820x->map[x].addr = final_start; + e820x->map[x].size = final_end - final_start; + e820x->map[x].type = new_type; + e820x->nr_map++; + real_updated_size += final_end - final_start; - ei->size -= final_end - final_start; if (ei->addr < final_start) continue; ei->addr = final_end; + ei->size -= final_end - final_start; } return real_updated_size; } @@ -1017,8 +1026,8 @@ u64 __init find_e820_area_size(u64 start continue; return addr; } - return -1UL; + return -1ULL; } /* @@ -1031,13 +1040,22 @@ u64 __init early_reserve_e820(u64 startt u64 start; start = startt; - while (size < sizet) + while (size < sizet && (start + 1)) start = find_e820_area_size(start, &size, align); if (size < sizet) return 0; +#ifdef CONFIG_X86_32 + if (start >= MAXMEM) + return 0; + if (start + size > MAXMEM) + size = MAXMEM - start; +#endif + addr = round_down(start + size - sizet, align); + if (addr < start) + return 0; e820_update_range(addr, sizet, E820_RAM, E820_RESERVED); e820_update_range_saved(addr, sizet, E820_RAM, E820_RESERVED); printk(KERN_INFO "update e820 for early_reserve_e820\n");