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=-3.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,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 725E0C3F68F for ; Tue, 14 Jan 2020 17:19:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 475A824670 for ; Tue, 14 Jan 2020 17:19:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=arista.com header.i=@arista.com header.b="Vjx3E4Jw" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728757AbgANRTY (ORCPT ); Tue, 14 Jan 2020 12:19:24 -0500 Received: from mail-pf1-f196.google.com ([209.85.210.196]:40064 "EHLO mail-pf1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728699AbgANRTY (ORCPT ); Tue, 14 Jan 2020 12:19:24 -0500 Received: by mail-pf1-f196.google.com with SMTP id q8so6883867pfh.7 for ; Tue, 14 Jan 2020 09:19:24 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=arista.com; s=googlenew; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=hq/EvgiMsTwoOsHfLL6j/V5911tAUEbQwTvWzcMkXl4=; b=Vjx3E4JwkKqeNef514E2ovt3+pcGt0kgEQ2W5bbWBdVQnRwAEXmmROtG5wMEX8qGaJ OAcGsk/n6T0N+lr8edoCWdlX7fU2cDxx2agWzou93FwA4WvcmvqIXNY+CIFMPttVakmp E3RL/FnLpgQ+zvA0ycAW2ybiZ3ScTlfsJ8RjpvhmPVBoT7zJQel5X6dCgYDtsgpryKa6 FC2jceLuGy3UlXNaQAezZ26/sudduCi3K932H9PkeugRA7FWOiJEMKmfjwdi4WUSvple U3Goq3AbiBs2mOSV6a+wGt45TFoXEFuadEYX3yxQCb/SNIQ+vTDlp3bqvJjS/LCSWTLx 6YkQ== 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:mime-version :content-transfer-encoding; bh=hq/EvgiMsTwoOsHfLL6j/V5911tAUEbQwTvWzcMkXl4=; b=cesEhn1XDdOdQ6YmgIpXouhSiNLYC7wT6ZI+CfdzIkynxiaq9U8F6pnA9B2ukE4I1k 5u+2QvaKXqampOMydPi4wamRz054lHpwcp7cAmsg5BPnmgl4mXEP1ZK9SM6KMq0NZKiI 0PICYY/veUtxFSKl2azenamrFC2ggpxWXJZEZ/i5I21G6OH3QFHgie9k2KQqpOVWVoRc C3Ai03i4Unz0lRDB4OPtzSP0Ww/41guK+lhSgG9F3ZxrTk9gXQKn9AlFfo7onls4tt4S wDXTW6kWSJ2L6FLGldNLKJ5o8wcqbTbdzMTNpPRIsu3I3BNf0xNACCzpz7FO00eqPh1v 07zg== X-Gm-Message-State: APjAAAU5eyHXHjZvL4/TbVLJCJj/LU5ckgLANxVsKSMhV/+OAoXd+c4s FUAXDx3F44ZztnnqdSrXSxQlw9gC9gA= X-Google-Smtp-Source: APXvYqw4cQ24d4qqEj9mv//Q3oGEq2B5gjJCmq88gtdREVehBYurFyG1jZyK0xA8XfyHNIbJT7usmw== X-Received: by 2002:a63:6fca:: with SMTP id k193mr29045745pgc.416.1579022363280; Tue, 14 Jan 2020 09:19:23 -0800 (PST) Received: from Mindolluin.ire.aristanetworks.com ([217.173.96.166]) by smtp.gmail.com with ESMTPSA id m128sm18965687pfm.183.2020.01.14.09.19.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 14 Jan 2020 09:19:22 -0800 (PST) From: Dmitry Safonov To: linux-kernel@vger.kernel.org Cc: Dmitry Safonov <0x7f454c46@gmail.com>, Dmitry Safonov , Greg Kroah-Hartman , Iurii Zaikin , Jiri Slaby , Joe Perches , Randy Dunlap , Vasiliy Khoruzhick , linux-serial@vger.kernel.org, Luis Chamberlain , Kees Cook , linux-fsdevel@vger.kernel.org Subject: [PATCHv2-next 0/3] serial/sysrq: Add MAGIC_SYSRQ_SERIAL_SEQUENCE Date: Tue, 14 Jan 2020 17:19:09 +0000 Message-Id: <20200114171912.261787-1-dima@arista.com> X-Mailer: git-send-email 2.24.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Magic sysrq has proven for Arista usecases to be useful for debugging issues in field, over serial line when the switch is in such bad state that it can't accept network connections anymore. Unfortunately, having sysrq always enabled doesn't work for some embedded boards that tend to generate garbage on serial line (including BREAKs). Since commit 732dbf3a6104 ("serial: do not accept sysrq characters via serial port"), it's possible to keep sysrq enabled, but over serial line. Add a way to enable sysrq on a uart, where currently it can be constantly either on or off (CONFIG_MAGIC_SYSRQ_SERIAL). While doing so, cleanup __sysrq_enabled and serial_core header file. Sending against -next tree as it's based on removing SUPPORT_SYSRQ ifdeffery [1]. Changes since v1 [2]: - Fix typo in pr_info() message (noticed by Randy Dunlap, thanks) - Add SYSRQ_TIMEOUT define for timeout after BREAK and separate removing @unused member of uart_port into cleanup patch (by Greg's review, thanks) - Add const qualifier, make uart_try_toggle_sysrq() bool function (Joe Perches, thanks) - Fix !CONFIG_SYSRQ and CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE="" build failures (kudos to kbuild test robot) [1]: https://lkml.kernel.org/r/20191213000657.931618-1-dima@arista.com [2]: https://lkml.kernel.org/r/20200109215444.95995-1-dima@arista.com Cc: Greg Kroah-Hartman Cc: Iurii Zaikin Cc: Jiri Slaby Cc: Joe Perches Cc: Randy Dunlap Cc: Vasiliy Khoruzhick Cc: linux-serial@vger.kernel.org Thanks, Dmitry Dmitry Safonov (3): sysctl/sysrq: Remove __sysrq_enabled copy serial/sysrq: Add MAGIC_SYSRQ_SERIAL_SEQUENCE serial_core: Remove unused member in uart_port drivers/tty/serial/serial_core.c | 75 +++++++++++++++++++++++++++++--- drivers/tty/sysrq.c | 7 +++ include/linux/serial_core.h | 2 +- include/linux/sysrq.h | 7 +++ kernel/sysctl.c | 41 +++++++++-------- lib/Kconfig.debug | 8 ++++ 6 files changed, 113 insertions(+), 27 deletions(-) -- 2.24.1