From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751398AbdAPULC (ORCPT ); Mon, 16 Jan 2017 15:11:02 -0500 Received: from smtp.codeaurora.org ([198.145.29.96]:37398 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750877AbdAPUK6 (ORCPT ); Mon, 16 Jan 2017 15:10:58 -0500 DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org CE810601A1 Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=tbaicar@codeaurora.org Subject: Re: [PATCH V7 04/10] arm64: exception: handle Synchronous External Abort To: Will Deacon References: <1484244924-24786-1-git-send-email-tbaicar@codeaurora.org> <1484244924-24786-5-git-send-email-tbaicar@codeaurora.org> <20170116115309.GE1510@arm.com> 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 From: "Baicar, Tyler" Message-ID: <0ca6c70e-6033-4cca-8833-15cb8573a939@codeaurora.org> Date: Mon, 16 Jan 2017 13:09:22 -0700 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.6.0 MIME-Version: 1.0 In-Reply-To: <20170116115309.GE1510@arm.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Will, 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. >> #endif /* __ASM_SYSTEM_MISC_H */ >> diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c >> index 05d2bd7..81039c7 100644 >> --- a/arch/arm64/mm/fault.c >> +++ b/arch/arm64/mm/fault.c >> @@ -39,6 +39,22 @@ >> #include >> #include >> >> +/* >> + * GHES SEA handler code may register a notifier call here to >> + * handle HW error record passed from platform. >> + */ >> +static ATOMIC_NOTIFIER_HEAD(sea_handler_chain); >> + >> +int register_sea_notifier(struct notifier_block *nb) >> +{ >> + return atomic_notifier_chain_register(&sea_handler_chain, nb); >> +} >> + >> +void unregister_sea_notifier(struct notifier_block *nb) >> +{ >> + atomic_notifier_chain_unregister(&sea_handler_chain, nb); >> +} >> + >> static const char *fault_name(unsigned int esr); >> >> #ifdef CONFIG_KPROBES >> @@ -480,6 +496,28 @@ static int do_bad(unsigned long addr, unsigned int esr, struct pt_regs *regs) >> return 1; >> } >> >> +/* >> + * This abort handler deals with Synchronous External Abort. >> + * It calls notifiers, and then returns "fault". >> + */ >> +static int do_sea(unsigned long addr, unsigned int esr, struct pt_regs *regs) >> +{ >> + struct siginfo info; >> + >> + atomic_notifier_call_chain(&sea_handler_chain, 0, NULL); >> + >> + pr_err("Synchronous External Abort: %s (0x%08x) at 0x%016lx\n", >> + fault_name(esr), esr, addr); >> + >> + info.si_signo = SIGBUS; >> + info.si_errno = 0; >> + info.si_code = 0; >> + info.si_addr = (void __user *)addr; >> + arm64_notify_die("", regs, &info, esr); >> + >> + return 0; >> +} >> + >> static const struct fault_info { >> int (*fn)(unsigned long addr, unsigned int esr, struct pt_regs *regs); >> int sig; >> @@ -502,22 +540,22 @@ static const struct fault_info { >> { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 1 permission fault" }, >> { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 2 permission fault" }, >> { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 3 permission fault" }, >> - { do_bad, SIGBUS, 0, "synchronous external abort" }, >> + { do_sea, SIGBUS, 0, "synchronous external abort" }, >> { do_bad, SIGBUS, 0, "unknown 17" }, >> { do_bad, SIGBUS, 0, "unknown 18" }, >> { do_bad, SIGBUS, 0, "unknown 19" }, >> - { do_bad, SIGBUS, 0, "synchronous abort (translation table walk)" }, >> - { do_bad, SIGBUS, 0, "synchronous abort (translation table walk)" }, >> - { do_bad, SIGBUS, 0, "synchronous abort (translation table walk)" }, >> - { do_bad, SIGBUS, 0, "synchronous abort (translation table walk)" }, >> - { do_bad, SIGBUS, 0, "synchronous parity error" }, >> + { do_sea, SIGBUS, 0, "level 0 SEA (translation table walk)" }, >> + { do_sea, SIGBUS, 0, "level 1 SEA (translation table walk)" }, >> + { do_sea, SIGBUS, 0, "level 2 SEA (translation table walk)" }, >> + { do_sea, SIGBUS, 0, "level 3 SEA (translation table walk)" }, > Perhaps I wasn't clear enough in my previous review, but please expand the > acronym for strings and comments. Sorry, I will expand these. >> + { do_sea, SIGBUS, 0, "synchronous parity or ECC err" }, > s/err/error/ > > Will Thanks, Tyler -- Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc. Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.