Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752428AbaJFXy3 (ORCPT ); Mon, 6 Oct 2014 19:54:29 -0400 Received: from mail-la0-f50.google.com ([209.85.215.50]:51814 "EHLO mail-la0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751252AbaJFXy2 (ORCPT ); Mon, 6 Oct 2014 19:54:28 -0400 MIME-Version: 1.0 In-Reply-To: <54332A64.5020605@caviumnetworks.com> References: <1412627010-4311-1-git-send-email-ddaney.cavm@gmail.com> <20141006205459.GZ23797@brightrain.aerifal.cx> <5433071B.4050606@caviumnetworks.com> <20141006213101.GA23797@brightrain.aerifal.cx> <54330D79.80102@caviumnetworks.com> <20141006215813.GB23797@brightrain.aerifal.cx> <543327E7.4020608@amacapital.net> <54332A64.5020605@caviumnetworks.com> From: Andy Lutomirski Date: Mon, 6 Oct 2014 16:54:06 -0700 Message-ID: Subject: Re: [PATCH resend] MIPS: Allow FPU emulator to use non-stack area. To: David Daney Cc: Rich Felker , David Daney , libc-alpha , "linux-kernel@vger.kernel.org" , Linux MIPS Mailing List , David Daney Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Oct 6, 2014 at 4:48 PM, David Daney wrote: > On 10/06/2014 04:38 PM, Andy Lutomirski wrote: >> >> On 10/06/2014 02:58 PM, Rich Felker wrote: >>> >>> On Mon, Oct 06, 2014 at 02:45:29PM -0700, David Daney wrote: > > [...] >>> >>> This is a huge ill-designed mess. >> >> >> Amen. >> >> Can the kernel not just emulate the instructions directly? > > > In theory it could, but since there can be implementation defined > instructions, there is no way to achieve full instruction set coverage for > all possible machines. Can modern user code just avoid constructs that require this kind of trampoline hack? If so, can this be solved the same way that x86 added no-exec stacks? (I.e. mark all the binaries as supporting non-executable stacks and letting them crash if they screw it up.) Knowing very little about MIPS, it sounds like this is the kernel compensating for a dumb assembler. --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/