From mboxrd@z Thu Jan 1 00:00:00 1970 From: yang.shi@linaro.org (Shi, Yang) Date: Tue, 10 Nov 2015 11:46:42 -0800 Subject: [PATCH] arm64: bpf: fix JIT stack setup In-Reply-To: References: <1446874577-14539-1-git-send-email-yang.shi@linaro.org> <20151108022726.GB39441@ast-mbp.thefacebook.com> <5640E135.2020007@linaro.org> Message-ID: <564249A2.1070903@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 >> >>