Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754106AbbHYHTa (ORCPT ); Tue, 25 Aug 2015 03:19:30 -0400 Received: from mail-ob0-f172.google.com ([209.85.214.172]:35574 "EHLO mail-ob0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751937AbbHYHT2 (ORCPT ); Tue, 25 Aug 2015 03:19:28 -0400 MIME-Version: 1.0 In-Reply-To: References: <1437745668-31802-1-git-send-email-dvlasenk@redhat.com> <1437745668-31802-2-git-send-email-dvlasenk@redhat.com> <55B68433.4040706@redhat.com> From: Andy Lutomirski Date: Tue, 25 Aug 2015 00:19:08 -0700 Message-ID: Subject: Re: [PATCH 2/3] x86/asm/entry/32: Remove most of SYSCALL32 code, part 1 To: Denys Vlasenko Cc: Ingo Molnar , Linus Torvalds , "Krzysztof A. Sobiecki" , Steven Rostedt , Borislav Petkov , "H. Peter Anvin" , Oleg Nesterov , Frederic Weisbecker , Alexei Starovoitov , Will Drewry , Kees Cook , X86 ML , "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: 1624 Lines: 36 On Mon, Jul 27, 2015 at 12:26 PM, Andy Lutomirski wrote: > On Mon, Jul 27, 2015 at 12:19 PM, Denys Vlasenko wrote: >> On 07/24/2015 07:50 PM, Andy Lutomirski wrote: >>> On Fri, Jul 24, 2015 at 6:47 AM, Denys Vlasenko wrote: >>>> SYSCALL32 code is nearly identical to SYSCALL32, except for initial >>>> section. Merge them. >>>> >>>> The removal is split into two parts, to make review eaiser. This is part 1. >>>> >>>> auditsys_entry_common and auditsys_exit macros are indented one more tab without >>>> any changes. This prevents diff from becoming unreadable. >>>> They will be removed in part 2. >>> >>> I need to read these more closely, which is, at present, exceeding my >>> ability to look at asm. (See the big NMI thread.) I'll look soon. >>> >>> Meanwhile, this code is incredibly fragile wrt syscall restart. >>> (Syscall restart on compat is really weird.) Do we have a decent test >>> for it? >> >> How about this? (Feel free to expand, this is a first cut only). > > On a very brief glance, it looks reasonable, but I'd try it with > recvfrom instead of recv because it's a six-argument syscall. > I was wondering how syscall restart works on compat syscalls on AMD (i.e. SYSCALL32). I think the answer is that it doesn't. Sigh. (Tested with ptrace instead of actual syscall restart.) --Andy -- 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/