Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751620AbbKJTqr (ORCPT ); Tue, 10 Nov 2015 14:46:47 -0500 Received: from mail-pa0-f54.google.com ([209.85.220.54]:35637 "EHLO mail-pa0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750906AbbKJTqo (ORCPT ); Tue, 10 Nov 2015 14:46:44 -0500 Message-ID: <564249A2.1070903@linaro.org> Date: Tue, 10 Nov 2015 11:46:42 -0800 From: "Shi, Yang" User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Z Lim CC: Alexei Starovoitov , Catalin Marinas , Will Deacon , Alexei Starovoitov , daniel@iogearbox.net, Xi Wang , LKML , Network Development , "linux-arm-kernel@lists.infradead.org" , linaro-kernel@lists.linaro.org Subject: Re: [PATCH] arm64: bpf: fix JIT stack setup References: <1446874577-14539-1-git-send-email-yang.shi@linaro.org> <20151108022726.GB39441@ast-mbp.thefacebook.com> <5640E135.2020007@linaro.org> In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1221 Lines: 37 On 11/9/2015 12:00 PM, Z Lim wrote: > On Mon, Nov 9, 2015 at 10:08 AM, Shi, Yang wrote: >> I added it to stay align with ARMv8 AAPCS to maintain the correct FP during >> function call. It makes us get correct stack backtrace. >> >> I think we'd better to keep compliant with ARMv8 AAPCS in BPF JIT prologue >> too. >> >> If nobody thinks it is necessary, we definitely could remove that change. > > Oh no, I don't think anyone will say it's unnecessary! > I agree the A64_FP-related change is a good idea, so stack unwinding works. > > How about splitting this into two patches? One for the BPF-related > bug, and another for A64 FP-handling. I'm not sure if this is a good approach or not. IMHO, they are kind of atomic. Without A64 FP-handling, that fix looks incomplete and introduces another problem (stack backtrace). Thanks, Yang > > Thanks again for tracking this down and improving things overall for arm64 :) > >> >> Thanks, >> Yang >> >> -- 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/