From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3E529C43461 for ; Fri, 11 Sep 2020 16:25:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EBFB222206 for ; Fri, 11 Sep 2020 16:25:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="ZJtKHlg2" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726520AbgIKQZD (ORCPT ); Fri, 11 Sep 2020 12:25:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33880 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726489AbgIKP2F (ORCPT ); Fri, 11 Sep 2020 11:28:05 -0400 Received: from mail-pj1-x1042.google.com (mail-pj1-x1042.google.com [IPv6:2607:f8b0:4864:20::1042]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6DA6BC0613ED for ; Fri, 11 Sep 2020 06:29:09 -0700 (PDT) Received: by mail-pj1-x1042.google.com with SMTP id q4so1716976pjh.5 for ; Fri, 11 Sep 2020 06:29:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id; bh=oE/wqoSbsqv2hid7WyjqPh05UOp+PSXcBf5enraQNIw=; b=ZJtKHlg2+Qyk+e6flWMUPDf2R513o9k5cmLgzNedw2Fzrrg2TvxtrJhrtQv/G77XDE Awr//OH53K23djlIRJOaWvkuYt4BNrys6dltOmdfdT0r3PEjxPlZUwZCQtXxU/Moq40h q8tzl6VH/S4mA5HfogBAqoBkTH8j4JawYnEFxnfseyHNyeC6gpvg1rXdTzZtJ0cyA66x vXv3S3Xva5+PN0uK92naQ70TX8GNxmqirwEau2oaGnz4uFwuz6Bb1M0pbU0Qt7RI8S1X pNbcdHKdv6hOCuM8Oyy0CEmdKQ1YhIYInxuI9eXNHyE5CBXZnMMkByo1QrJPzvwwZnZs z8yA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=oE/wqoSbsqv2hid7WyjqPh05UOp+PSXcBf5enraQNIw=; b=f57r52Z3nGzED1mk4FeAlLoIFrYSL5I8YO0OfENQU2ZO4WlbqToSP/nJv1bgMyNJZF LW+f09P8bJHnwb6XhBNcswHM1IvOF+6t5n6FAitEm0dUSrhWwiZFLQ+qSGa/4UsFtbKx ZsFTCxvYuodqfiG6zCibjKaa8Oj5Rra25bVyEHbH4PhluuA2IP63UwxcudJESqU4Lj/u 5oiD4ROxIG/Y/NJUGTf66I+otVoVOOVsKCL2u5YJ6oXEKlC5m8HumuI8+COjyJLMdV7K JtOhoDVnvh4f7jkbBS8Hs/Yo16gBowe0V7zM1utTGlYUmuEbBxAp+ktmhH0SkK6gP8yh /AoA== X-Gm-Message-State: AOAM531j74pD4eB4aDggR9h5P0Ca99EtNdhtMf/dAu5z5D2GmpSFK6Ne 3KK/CmKismed9kltcobh2ddt1Q== X-Google-Smtp-Source: ABdhPJxbjdUv3H0gL8OHcqKBS2SE0Vo7mVcMOQlitX0foG0MQcL6w/a4cRDFyo1GcgHsYfGc3CZIPQ== X-Received: by 2002:a17:90a:ec05:: with SMTP id l5mr2392447pjy.172.1599830948206; Fri, 11 Sep 2020 06:29:08 -0700 (PDT) Received: from localhost.localdomain ([117.210.209.48]) by smtp.gmail.com with ESMTPSA id e10sm557988pgb.45.2020.09.11.06.29.01 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Fri, 11 Sep 2020 06:29:07 -0700 (PDT) From: Sumit Garg To: maz@kernel.org, catalin.marinas@arm.com, will@kernel.org Cc: linux-arm-kernel@lists.infradead.org, tglx@linutronix.de, jason@lakedaemon.net, mark.rutland@arm.com, julien.thierry.kdev@gmail.com, dianders@chromium.org, daniel.thompson@linaro.org, jason.wessel@windriver.com, kgdb-bugreport@lists.sourceforge.net, linux-kernel@vger.kernel.org, Sumit Garg Subject: [PATCH v4 0/5] arm64: Add framework to turn an IPI as NMI Date: Fri, 11 Sep 2020 18:58:39 +0530 Message-Id: <1599830924-13990-1-git-send-email-sumit.garg@linaro.org> X-Mailer: git-send-email 2.7.4 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org With pseudo NMIs support available its possible to configure SGIs to be triggered as pseudo NMIs running in NMI context. And kernel features such as: - NMI backtrace can leverage IPI turned as NMI to get a backtrace of CPU stuck in hard lockup using magic SYSRQ. - kgdb relies on NMI support to round up CPUs which are stuck in hard lockup state with interrupts disabled. This patch-set adds framework to turn an IPI as NMI which can be triggered as a pseudo NMI which in turn invokes registered NMI handlers. After this patch-set we should be able to get a backtrace for a CPU stuck in HARDLOCKUP. Have a look at an examples below from a hard lockup testcase run on Developerbox: $ echo HARDLOCKUP > /sys/kernel/debug/provoke-crash/DIRECT NMI backtrace: ============== # Issue Magic SysRq to dump backtrace [ 376.894502] NMI backtrace for cpu 8 [ 376.894506] CPU: 8 PID: 555 Comm: bash Not tainted 5.9.0-rc3-00740-g06ff047-dirty #242 [ 376.894510] Hardware name: Socionext SynQuacer E-series DeveloperBox, BIOS build #73 Apr 6 2020 [ 376.894514] pstate: 40000005 (nZcv daif -PAN -UAO BTYPE=--) [ 376.894517] pc : lkdtm_HARDLOCKUP+0x8/0x18 [ 376.894520] lr : lkdtm_do_action+0x24/0x30 [ 376.894524] sp : ffff800012cebd20 [ 376.894527] pmr_save: 00000060 [ 376.894530] x29: ffff800012cebd20 x28: ffff000875ae8000 [ 376.894540] x27: 0000000000000000 x26: 0000000000000000 [ 376.894550] x25: 000000000000001a x24: ffff800012cebe40 [ 376.894560] x23: 000000000000000b x22: ffff800010fc5040 [ 376.894569] x21: ffff000878b61000 x20: ffff8000113b2870 [ 376.894579] x19: 000000000000001b x18: 0000000000000010 [ 376.894588] x17: 0000000000000000 x16: 0000000000000000 [ 376.894598] x15: ffff000875ae8470 x14: 00000000000002ad [ 376.894613] x13: 0000000000000000 x12: 0000000000000000 [ 376.894622] x11: 0000000000000007 x10: 00000000000009c0 [ 376.894631] x9 : ffff800012ceba80 x8 : ffff000875ae8a20 [ 376.894641] x7 : ffff00087f6b3280 x6 : ffff00087f6b3200 [ 376.894651] x5 : 0000000000000000 x4 : ffff00087f6a91f8 [ 376.894660] x3 : ffff00087f6b0120 x2 : 1aa310cec69eb500 [ 376.894670] x1 : 0000000000000000 x0 : 0000000000000060 [ 376.894679] Call trace: [ 376.894683] lkdtm_HARDLOCKUP+0x8/0x18 [ 376.894686] direct_entry+0x124/0x1c0 [ 376.894689] full_proxy_write+0x60/0xb0 [ 376.894693] vfs_write+0xf0/0x230 [ 376.894696] ksys_write+0x6c/0xf8 [ 376.894699] __arm64_sys_write+0x1c/0x28 [ 376.894703] el0_svc_common.constprop.0+0x74/0x1f0 [ 376.894707] do_el0_svc+0x24/0x90 [ 376.894710] el0_sync_handler+0x180/0x2f8 [ 376.894713] el0_sync+0x158/0x180 KGDB: ===== # Enter kdb via Magic SysRq [6]kdb> btc btc: cpu status: Currently on cpu 6 Available cpus: 0-5(I), 6, 7(I), 8, 9-23(I) Stack traceback for pid 555 0xffff000875ae8000 555 554 1 8 R 0xffff000875ae89c0 bash CPU: 8 PID: 555 Comm: bash Not tainted 5.9.0-rc3-00740-g06ff047-dirty #242 Hardware name: Socionext SynQuacer E-series DeveloperBox, BIOS build #73 Apr 6 2020 Call trace: dump_backtrace+0x0/0x1a0 show_stack+0x18/0x28 dump_stack+0xc0/0x11c kgdb_cpu_enter+0x648/0x660 kgdb_nmicallback+0xa0/0xa8 ipi_kgdb_nmicallback+0x24/0x30 ipi_nmi_handler+0x48/0x60 handle_percpu_devid_fasteoi_ipi+0x74/0x88 generic_handle_irq+0x30/0x48 handle_domain_nmi+0x48/0x80 gic_handle_irq+0x18c/0x34c el1_irq+0xcc/0x180 lkdtm_HARDLOCKUP+0x8/0x18 direct_entry+0x124/0x1c0 full_proxy_write+0x60/0xb0 vfs_write+0xf0/0x230 ksys_write+0x6c/0xf8 __arm64_sys_write+0x1c/0x28 el0_svc_common.constprop.0+0x74/0x1f0 do_el0_svc+0x24/0x90 el0_sync_handler+0x180/0x2f8 el0_sync+0x158/0x180 Changes in v4: - Move IPI NMI framework to a separate file. - Get rid of hard-coded IPI_CALL_NMI_FUNC allocation. - Add NMI backtrace support leveraged via magic SYSRQ. Changes in v3: - Rebased to Marc's latest IPIs patch-set [1]. [1] https://lkml.org/lkml/2020/9/1/603 Changes since RFC version [1]: - Switch to use generic interrupt framework to turn an IPI as NMI. - Dependent on Marc's patch-set [2] which turns IPIs into normal interrupts. - Addressed misc. comments from Doug on patch #4. - Posted kgdb NMI printk() fixup separately which has evolved since to be solved using different approach via changing kgdb interception of printk() in common printk() code (see patch [3]). [1] https://lkml.org/lkml/2020/4/24/328 [2] https://lkml.org/lkml/2020/5/19/710 [3] https://lkml.org/lkml/2020/5/20/418 Sumit Garg (5): arm64: Add framework to turn IPI as NMI irqchip/gic-v3: Enable support for SGIs to act as NMIs arm64: smp: Allocate and setup IPI as NMI arm64: kgdb: Round up cpus using IPI as NMI arm64: ipi_nmi: Add support for NMI backtrace arch/arm64/include/asm/irq.h | 6 +++ arch/arm64/include/asm/kgdb.h | 8 ++++ arch/arm64/include/asm/nmi.h | 16 ++++++++ arch/arm64/kernel/Makefile | 2 +- arch/arm64/kernel/ipi_nmi.c | 93 +++++++++++++++++++++++++++++++++++++++++++ arch/arm64/kernel/kgdb.c | 21 ++++++++++ arch/arm64/kernel/smp.c | 8 ++++ drivers/irqchip/irq-gic-v3.c | 13 +++++- 8 files changed, 164 insertions(+), 3 deletions(-) create mode 100644 arch/arm64/include/asm/nmi.h create mode 100644 arch/arm64/kernel/ipi_nmi.c -- 2.7.4