Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752386AbbL0G53 (ORCPT ); Sun, 27 Dec 2015 01:57:29 -0500 Received: from mail-wm0-f46.google.com ([74.125.82.46]:34370 "EHLO mail-wm0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750942AbbL0G52 (ORCPT ); Sun, 27 Dec 2015 01:57:28 -0500 MIME-Version: 1.0 In-Reply-To: References: <20151224214632.GF4128@pd.tnic> <20151225114937.GA862@pd.tnic> <5FBC1CF1-095B-466D-85D6-832FBFA98364@intel.com> <20151226103252.GA21988@pd.tnic> Date: Sat, 26 Dec 2015 22:57:26 -0800 Message-ID: Subject: Re: [PATCHV5 3/3] x86, ras: Add __mcsafe_copy() function to recover from machine checks From: Tony Luck To: Andy Lutomirski Cc: Borislav Petkov , linux-nvdimm , X86 ML , "elliott@hpe.com" , "linux-mm@kvack.org" , Andrew Morton , "Williams, Dan J" , Ingo Molnar , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1109 Lines: 27 On Sat, Dec 26, 2015 at 6:16 PM, Andy Lutomirski wrote: >>> We could make one of them 31-bits (since even an "allyesconfig" kernel >>> is still much smaller than a gigabyte) to free a bit for a flag. But there >>> are those external tools to pre-sort exception tables that would all >>> need to be fixed too. > > Wait, why? The external tools sort by source address, and we'd > squeeze the flag into the target address, no? I was thinking that we'd need to recompute the fixup when we move the entry to its new sorted location. So that: ex_fixup_addr(const struct exception_table_entry *x) { return (unsigned long)&x->fixup + x->fixup; } will get the right value. Maybe this would still work out if the fixup is a 31-bit value plus a flag, but the external tool thinks it is a 32-bit value? I'd have to ponder that. -Tony -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/