From mboxrd@z Thu Jan 1 00:00:00 1970 From: Will Deacon Subject: Re: [PATCH] arm64: reenable interrupt when handling ptrace breakpoint Date: Wed, 13 Jan 2016 17:23:03 +0000 Message-ID: <20160113172303.GH25458@arm.com> References: <1450225088-2456-1-git-send-email-yang.shi@linaro.org> <20151216111316.GD4308@arm.com> <5671CD5B.9030907@linaro.org> <20151221104818.GF23092@arm.com> <20151221170028.GT23092@arm.com> <56955B3A.5010303@linaro.org> <20160113102622.GC25458@arm.com> <569686BA.6050703@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Thomas Gleixner , Catalin.Marinas@arm.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linaro-kernel@lists.linaro.org, linux-rt-users@vger.kernel.org To: "Shi, Yang" Return-path: Content-Disposition: inline In-Reply-To: <569686BA.6050703@linaro.org> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-rt-users.vger.kernel.org On Wed, Jan 13, 2016 at 09:17:46AM -0800, Shi, Yang wrote: > On 1/13/2016 2:26 AM, Will Deacon wrote: > >On Tue, Jan 12, 2016 at 11:59:54AM -0800, Shi, Yang wrote: > >>This might be buried in email storm during the holiday. Just want to double > >>check the status. I'm supposed there is no objection for getting it merged > >>in upstream? > > > >Sorry, when you replied with: > > > >>I think we could just extend the "signal delay send" approach from x86-64 > >>to arm64, which is currently used by x86-64 on -rt kernel only. > > > >I understood that you were going to fix -rt, so I dropped this pending > >anything more from you. > > > >What's the plan? > > Sorry for the confusion. The "signal delay send" approach used by x86-64 -rt > should be not necessary for arm64 right now. Reenabling interrupt is still > the preferred approach. > > Since x86-64 has per-CPU IST exception stack, so preemption has to be > disabled all the time. However, it is not applicable to other architectures > for now, including arm64. Actually, we grew support for a separate IRQ stack in the recent merge window. Does that change things here, or are you referring to something else? Will