From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751275AbdAQK15 (ORCPT ); Tue, 17 Jan 2017 05:27:57 -0500 Received: from foss.arm.com ([217.140.101.70]:46282 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750929AbdAQK1z (ORCPT ); Tue, 17 Jan 2017 05:27:55 -0500 Date: Tue, 17 Jan 2017 10:27:53 +0000 From: Will Deacon To: "Baicar, Tyler" Cc: christoffer.dall@linaro.org, marc.zyngier@arm.com, pbonzini@redhat.com, rkrcmar@redhat.com, linux@armlinux.org.uk, catalin.marinas@arm.com, rjw@rjwysocki.net, lenb@kernel.org, matt@codeblueprint.co.uk, robert.moore@intel.com, lv.zheng@intel.com, nkaje@codeaurora.org, zjzhang@codeaurora.org, mark.rutland@arm.com, james.morse@arm.com, akpm@linux-foundation.org, eun.taik.lee@samsung.com, sandeepa.s.prabhu@gmail.com, labbott@redhat.com, shijie.huang@arm.com, rruigrok@codeaurora.org, paul.gortmaker@windriver.com, tn@semihalf.com, fu.wei@linaro.org, rostedt@goodmis.org, bristot@redhat.com, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, linux-efi@vger.kernel.org, devel@acpica.org, Suzuki.Poulose@arm.com, punit.agrawal@arm.com, astone@redhat.com, harba@codeaurora.org, hanjun.guo@linaro.org, john.garry@huawei.com, shiju.jose@huawei.com Subject: Re: [PATCH V7 04/10] arm64: exception: handle Synchronous External Abort Message-ID: <20170117102753.GA27328@arm.com> References: <1484244924-24786-1-git-send-email-tbaicar@codeaurora.org> <1484244924-24786-5-git-send-email-tbaicar@codeaurora.org> <20170116115309.GE1510@arm.com> <0ca6c70e-6033-4cca-8833-15cb8573a939@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0ca6c70e-6033-4cca-8833-15cb8573a939@codeaurora.org> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jan 16, 2017 at 01:09:22PM -0700, Baicar, Tyler wrote: > On 1/16/2017 4:53 AM, Will Deacon wrote: > >On Thu, Jan 12, 2017 at 11:15:18AM -0700, Tyler Baicar wrote: > >>SEA exceptions are often caused by an uncorrected hardware > >>error, and are handled when data abort and instruction abort > >>exception classes have specific values for their Fault Status > >>Code. > >>When SEA occurs, before killing the process, go through > >>the handlers registered in the notification list. > >>Update fault_info[] with specific SEA faults so that the > >>new SEA handler is used. > >> > >>Signed-off-by: Tyler Baicar > >>Signed-off-by: Jonathan (Zhixiong) Zhang > >>Signed-off-by: Naveen Kaje > >>--- > >> arch/arm64/include/asm/system_misc.h | 13 ++++++++ > >> arch/arm64/mm/fault.c | 58 +++++++++++++++++++++++++++++------- > >> 2 files changed, 61 insertions(+), 10 deletions(-) > >> > >>diff --git a/arch/arm64/include/asm/system_misc.h b/arch/arm64/include/asm/system_misc.h > >>index 57f110b..e7f3440 100644 > >>--- a/arch/arm64/include/asm/system_misc.h > >>+++ b/arch/arm64/include/asm/system_misc.h > >>@@ -64,4 +64,17 @@ extern void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd); > >> #endif /* __ASSEMBLY__ */ > >>+/* > >>+ * The functions below are used to register and unregister callbacks > >>+ * that are to be invoked when a Synchronous External Abort (SEA) > >>+ * occurs. An SEA is raised by certain fault status codes that have > >>+ * either data or instruction abort as the exception class, and > >>+ * callbacks may be registered to parse or handle such hardware errors. > >>+ * > >>+ * Registered callbacks are run in an interrupt/atomic context. They > >>+ * are not allowed to block or sleep. > >>+ */ > >>+int register_sea_notifier(struct notifier_block *nb); > >>+void unregister_sea_notifier(struct notifier_block *nb); > >I still don't understand why you need notifiers for this. You register > >precisely one hook in the series. > I didn't see a response to my last comment on the previous series so I just > left it in for this series. > The notifier usage is consistent with the GHES code for SCI errors which are > also only used a single > time in the code. If you think making the call directly is a better option I > will remove the notifiers. Yes, please. It's easy to add the notifier infrastructure back if/when it's actually needed and I don't see why the low-level fault dispatching needs to be consistent with the GHES/SCI code. Will