Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932399AbaJGT2m (ORCPT ); Tue, 7 Oct 2014 15:28:42 -0400 Received: from mail-lb0-f176.google.com ([209.85.217.176]:44694 "EHLO mail-lb0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932348AbaJGT2k (ORCPT ); Tue, 7 Oct 2014 15:28:40 -0400 MIME-Version: 1.0 In-Reply-To: <20141007192107.GN23797@brightrain.aerifal.cx> References: <54332A64.5020605@caviumnetworks.com> <20141007000514.GD23797@brightrain.aerifal.cx> <543334CE.8060305@caviumnetworks.com> <20141007004915.GF23797@brightrain.aerifal.cx> <54337127.40806@gmail.com> <6D39441BF12EF246A7ABCE6654B0235320F1E173@LEMAIL01.le.imgtec.org> <543431DA.4090809@imgtec.com> <20141007190943.GM23797@brightrain.aerifal.cx> <54343C2B.2080801@imgtec.com> <20141007192107.GN23797@brightrain.aerifal.cx> From: Andy Lutomirski Date: Tue, 7 Oct 2014 12:28:18 -0700 Message-ID: Subject: Re: [PATCH resend] MIPS: Allow FPU emulator to use non-stack area. To: Rich Felker Cc: Leonid Yegoshin , Matthew Fortune , David Daney , David Daney , David Daney , "libc-alpha@sourceware.org" , "linux-kernel@vger.kernel.org" , "linux-mips@linux-mips.org" , 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 Tue, Oct 7, 2014 at 12:21 PM, Rich Felker wrote: > On Tue, Oct 07, 2014 at 12:16:59PM -0700, Leonid Yegoshin wrote: >> On 10/07/2014 12:09 PM, Rich Felker wrote: >> >I agree completely here. We should not break things (or, as it >> >seems, leave them broken) for common usage cases that affect >> >everyone just to coddle proprietary vendor-specific instructions. >> >The latter just should not be used in delay slots unless the chip >> >vendor also promises to provide fpu branch in hardware. Rich >> And what do you propose - remove a current in-stack emulation and >> you still think it doesn't break a status-quo? > > The in-stack trampoline support could be left but used only for > emulating instructions the kernel doesn't know. This would make all > normal binaries immediately usable with non-executable stack, and > would avoid the only potential source of regressions. Ultimately I > think the "xol" stuff should be removed, but that could be a long term > goal. Does anything break if the xol stuff is disabled for PT_GNU_STACK tasks? > > Rich -- 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/