Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752057AbbHLUBX (ORCPT ); Wed, 12 Aug 2015 16:01:23 -0400 Received: from mail-oi0-f47.google.com ([209.85.218.47]:36549 "EHLO mail-oi0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751083AbbHLUBW convert rfc822-to-8bit (ORCPT ); Wed, 12 Aug 2015 16:01:22 -0400 MIME-Version: 1.0 In-Reply-To: <55CBA4CE.1040108@list.ru> References: <55CA90B4.2010205@list.ru> <55CAFD9F.2070001@list.ru> <55CB7BAE.9090503@list.ru> <55CB9697.1050602@list.ru> <55CBA4CE.1040108@list.ru> From: Andy Lutomirski Date: Wed, 12 Aug 2015 13:01:02 -0700 Message-ID: Subject: Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu To: Stas Sergeev Cc: X86 ML , Linux kernel Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1211 Lines: 28 On Wed, Aug 12, 2015 at 12:55 PM, Stas Sergeev wrote: > 12.08.2015 22:20, Andy Lutomirski пишет: >> current kernels, it stays switched. If we change this, it won't stay >> switched. Even ignoring old ABI, it's not really clear to me what the >> right thing to do is. > > There can be the following cases: > - switch_userspace_thread() switches fs to non-zero selector > - switch_userspace_thread() switches the fs base via syscall > - switch_userspace_thread() switches fs in sigcontext > - switch_userspace_thread() switches fs_base in sigcontext (???) > What exactly case do you have in mind? > I'd say, the way x86_32 is doing things - is good, but the > bases... perhaps, in ideal world, they should be a part of > the sigcontext as well? Any of the above. What do you want the kernel to do, and how does the kernel know you want to do that? The kernel has to pick *some* semantics here. -- Andy Lutomirski AMA Capital Management, LLC -- 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/