Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932247AbaJGTWa (ORCPT ); Tue, 7 Oct 2014 15:22:30 -0400 Received: from 216-12-86-13.cv.mvl.ntelos.net ([216.12.86.13]:59769 "EHLO brightrain.aerifal.cx" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932132AbaJGTWT (ORCPT ); Tue, 7 Oct 2014 15:22:19 -0400 Date: Tue, 7 Oct 2014 15:21:07 -0400 From: Rich Felker To: Leonid Yegoshin Cc: Andy Lutomirski , Matthew Fortune , David Daney , David Daney , David Daney , "libc-alpha@sourceware.org" , "linux-kernel@vger.kernel.org" , "linux-mips@linux-mips.org" , David Daney Subject: Re: [PATCH resend] MIPS: Allow FPU emulator to use non-stack area. Message-ID: <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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <54343C2B.2080801@imgtec.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Rich -- 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/