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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 05B36EE6447 for ; Fri, 15 Sep 2023 09:13:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type:MIME-Version: References:Message-ID:In-Reply-To:Subject:cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Z67768QYgOzLMHQXfSOQOgBwrjzA8arAbTjrhXUChLU=; b=qABQS8jhb9Gu1yzcYPibldJVOQ lEY1PkJgzpr8vKJrfnAIjzJT05+QxD8kIYDZfrLa2lKwfGKhIdGR2zuUacGlpimUVb7fuYCLyrpIg IuYPT2s4AadwZxAmjl82x7ATW9XwYH2/vfUaZzeVh5gW14G58haPr7dIubSaoPnuIpzUpSAnks438 Jlgs6y+HNmPmRDzM+6pZ17KYj3bVZHYD/4G8MvIUG0ibiaOprFsKnOEo32KjnL37klU+siF+WrmnH fT3erIVahpSMmttOMep2SDqLGTEqvLlgwFXIkYS7bGi7ef8sS7sEMumUV6bvKXThU3gRPsYWPODFg dEKpXpQA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qh4tX-00AEZm-3A; Fri, 15 Sep 2023 09:13:47 +0000 Received: from mgamail.intel.com ([192.55.52.120]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qh4tT-00AEYX-0n; Fri, 15 Sep 2023 09:13:45 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1694769223; x=1726305223; h=date:from:to:cc:subject:in-reply-to:message-id: references:mime-version; bh=mry5V7nr5xa9zDtsfeoNxabJToApg0Wq8K46aPBD860=; b=K2aHuLgvaqRj0lpduW9Mx6B9mAX1LEv2kVgWLDQCAN960LP9xJ2hv0H9 JJmGx10iUoBgi1WEcu/kx1r9Qq8nJEuxqPPbws/qhcksmfKagtNpPYU2w q3LpPiPg75MbKJyzq158qscu2st3ZR2bluMdu/C0sJTPNRvNoT7vc32I8 ihL4wSOKdmyucrcxFa3Krf0jLi7jzj/rlW4J2y7TD83jgUTyJZc4BGabm hs9X8OIwmpRSOuPyQSmNWZwGwVV7Szs0oda+DBhVFDd+qot6HFS8BdTi1 FIrvRhXuQe2zuyt5CxyEsiOb6BduYzYlV7XkRAkOjLx522ChgzxTuXdHz Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10833"; a="378120581" X-IronPort-AV: E=Sophos;i="6.02,148,1688454000"; d="scan'208";a="378120581" Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Sep 2023 02:13:33 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10833"; a="918589081" X-IronPort-AV: E=Sophos;i="6.02,148,1688454000"; d="scan'208";a="918589081" Received: from srdoo-mobl1.ger.corp.intel.com ([10.252.38.99]) by orsmga005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Sep 2023 02:13:03 -0700 Date: Fri, 15 Sep 2023 12:12:58 +0300 (EEST) From: =?ISO-8859-15?Q?Ilpo_J=E4rvinen?= To: John Ogness cc: Greg Kroah-Hartman , Jiri Slaby , linux-serial , Petr Mladek , Thomas Gleixner , LKML , Tobias Klauser , Thierry Reding , Joel Stanley , Andrew Jeffery , linux-arm-kernel@lists.infradead.org, linux-aspeed@lists.ozlabs.org, Al Cooper , Broadcom internal kernel review list , Tony Lindgren , Andy Shevchenko , =?ISO-8859-15?Q?Ilpo_J=E4rvinen?= , Florian Fainelli , Andrew Davis , Matthew Howell , =?ISO-8859-15?Q?Uwe_Kleine-K=F6nig?= , Johan Hovold , Matthias Brugger , AngeloGioacchino Del Regno , Chen-Yu Tsai , linux-mediatek@lists.infradead.org, Lukas Wunner , Matthias Schiffer , Arnd Bergmann , Kumaravel Thiagarajan , Tharun Kumar P , Russell King , "Maciej W. Rozycki" , Hongyu Xie , Jiamei Xie , Rob Herring , delisun , Lino Sanfilippo , Yangtao Li , Vineet Gupta , linux-snps-arc@lists.infradead.org, Richard Genoud , Nicolas Ferre , Alexandre Belloni , Claudiu Beznea , Arend van Spriel , Christophe Leroy , Baruch Siach , Sherry Sun , Shenwei Wang , Shawn Guo , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , NXP Linux Team , Sergey Organov , Tom Rix , Marek Vasut , Karol Gugala , Mateusz Holenko , Gabriel Somlo , Vladimir Zapolskiy , Jacky Huang , Shan-Chun Hung , Neil Armstrong , Kevin Hilman , Jerome Brunet , Martin Blumenstingl , Dmitry Rokosov , Lucas Tanure , linux-amlogic@lists.infradead.org, Taichi Sugaya , Takao Orito , Liviu Dudau , Sudeep Holla , Lorenzo Pieralisi , Andy Gross , Bjorn Andersson , Konrad Dybcio , linux-arm-msm@vger.kernel.org, =?ISO-8859-15?Q?Pali_Roh=E1r?= , Andrew Morton , =?ISO-8859-15?Q?Andreas_F=E4rber?= , Manivannan Sadhasivam , linux-actions@lists.infradead.org, Xiongfeng Wang , Yuan Can , Michael Ellerman , Nicholas Piggin , linuxppc-dev@lists.ozlabs.org, linux-unisoc@lists.infradead.org, Kevin Cernekee , Krzysztof Kozlowski , Alim Akhtar , linux-samsung-soc@vger.kernel.org, Lukas Bulwahn , Lech Perczak , Hugo Villeneuve , Andy Shevchenko , Isaac True , Laxman Dewangan , Thierry Reding , Jonathan Hunter , linux-tegra@vger.kernel.org, Biju Das , Geert Uytterhoeven , Palmer Dabbelt , Paul Walmsley , Nick Hu , Ruan Jinjie , Samuel Holland , linux-riscv@lists.infradead.org, Orson Zhai , Baolin Wang , Chunyan Zhang , Patrice Chotard , Maxime Coquelin , Alexandre Torgue , Valentin Caron , Sebastian Andrzej Siewior , linux-stm32@st-md-mailman.stormreply.com, "David S. Miller" , sparclinux@vger.kernel.org, Hammer Hsieh , Peter Korsgaard , Timur Tabi , Mukesh Ojha , =?ISO-8859-15?Q?Jonathan_Neusch=E4fer?= , Michal Simek Subject: Re: [PATCH tty v1 00/74] serial: wrappers for uart port lock In-Reply-To: <20230914183831.587273-1-john.ogness@linutronix.de> Message-ID: <1446dc6-5ab0-629-45c8-3b7d8c76367d@linux.intel.com> References: <20230914183831.587273-1-john.ogness@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230915_021343_330722_A1FC01C9 X-CRM114-Status: GOOD ( 27.21 ) X-BeenThere: linux-mediatek@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-mediatek" Errors-To: linux-mediatek-bounces+linux-mediatek=archiver.kernel.org@lists.infradead.org On Thu, 14 Sep 2023, John Ogness wrote: > When a serial port is used for kernel console output, then all > modifications to the UART registers which are done from other contexts, > e.g. getty, termios, are interference points for the kernel console. > > So far this has been ignored and the printk output is based on the > principle of hope. The rework of the console infrastructure which aims to > support threaded and atomic consoles, requires to mark sections which > modify the UART registers as unsafe. This allows the atomic write function > to make informed decisions and eventually to restore operational state. It > also allows to prevent the regular UART code from modifying UART registers > while printk output is in progress. Hi John, Would this also be useful to enable printing to console while under port's lock (by postponing the output until the lock is released)? E.g., 8250_dw.c has had this commented out since the dawn on time: /* * FIXME: this deadlocks if port->lock is already held * dev_err(p->dev, "Couldn't set LCR to %d\n", value); */ -- i. > All modifications of UART registers are guarded by the UART port lock, > which provides an obvious synchronization point with the console > infrastructure. > > Provide and use wrapper functions for spin_[un]lock*(port->lock) > invocations so that the console mechanics can be applied later on at a > single place and does not require to copy the same logic all over the > drivers. > > Patch 1 adds the wrapper functions. > > Patches 2-74 switch all uart port locking call sites to use the new > wrappers. These patches were automatically generated using coccinelle. > The 2 used coccinelle scripts are included below and executed as > follows: > > $ spatch --sp-file uartlock-1.cocci $FILE > $ spatch --sp-file uartlock-2.cocci --recursive-includes $FILE > > This series brings no functional change. > > Patches 2-74 contain identical commit message bodies. Feel free to > fold them into a single commit if that seems more reasonable. > > Thomas Gleixner (74): > serial: core: Provide port lock wrappers > serial: core: Use lock wrappers > serial: 21285: Use port lock wrappers > serial: 8250_aspeed_vuart: Use port lock wrappers > serial: 8250_bcm7271: Use port lock wrappers > serial: 8250: Use port lock wrappers > serial: 8250_dma: Use port lock wrappers > serial: 8250_dw: Use port lock wrappers > serial: 8250_exar: Use port lock wrappers > serial: 8250_fsl: Use port lock wrappers > serial: 8250_mtk: Use port lock wrappers > serial: 8250_omap: Use port lock wrappers > serial: 8250_pci1xxxx: Use port lock wrappers > serial: altera_jtaguart: Use port lock wrappers > serial: altera_uart: Use port lock wrappers > serial: amba-pl010: Use port lock wrappers > serial: amba-pl011: Use port lock wrappers > serial: apb: Use port lock wrappers > serial: ar933x: Use port lock wrappers > serial: arc_uart: Use port lock wrappers > serial: atmel: Use port lock wrappers > serial: bcm63xx-uart: Use port lock wrappers > serial: cpm_uart: Use port lock wrappers > serial: digicolor: Use port lock wrappers > serial: dz: Use port lock wrappers > serial: linflexuart: Use port lock wrappers > serial: fsl_lpuart: Use port lock wrappers > serial: icom: Use port lock wrappers > serial: imx: Use port lock wrappers > serial: ip22zilog: Use port lock wrappers > serial: jsm: Use port lock wrappers > serial: liteuart: Use port lock wrappers > serial: lpc32xx_hs: Use port lock wrappers > serial: ma35d1: Use port lock wrappers > serial: mcf: Use port lock wrappers > serial: men_z135_uart: Use port lock wrappers > serial: meson: Use port lock wrappers > serial: milbeaut_usio: Use port lock wrappers > serial: mpc52xx: Use port lock wrappers > serial: mps2-uart: Use port lock wrappers > serial: msm: Use port lock wrappers > serial: mvebu-uart: Use port lock wrappers > serial: omap: Use port lock wrappers > serial: owl: Use port lock wrappers > serial: pch: Use port lock wrappers > serial: pic32: Use port lock wrappers > serial: pmac_zilog: Use port lock wrappers > serial: pxa: Use port lock wrappers > serial: qcom-geni: Use port lock wrappers > serial: rda: Use port lock wrappers > serial: rp2: Use port lock wrappers > serial: sa1100: Use port lock wrappers > serial: samsung_tty: Use port lock wrappers > serial: sb1250-duart: Use port lock wrappers > serial: sc16is7xx: Use port lock wrappers > serial: tegra: Use port lock wrappers > serial: core: Use port lock wrappers > serial: mctrl_gpio: Use port lock wrappers > serial: txx9: Use port lock wrappers > serial: sh-sci: Use port lock wrappers > serial: sifive: Use port lock wrappers > serial: sprd: Use port lock wrappers > serial: st-asc: Use port lock wrappers > serial: stm32: Use port lock wrappers > serial: sunhv: Use port lock wrappers > serial: sunplus-uart: Use port lock wrappers > serial: sunsab: Use port lock wrappers > serial: sunsu: Use port lock wrappers > serial: sunzilog: Use port lock wrappers > serial: timbuart: Use port lock wrappers > serial: uartlite: Use port lock wrappers > serial: ucc_uart: Use port lock wrappers > serial: vt8500: Use port lock wrappers > serial: xilinx_uartps: Use port lock wrappers > > drivers/tty/serial/21285.c | 8 +- > drivers/tty/serial/8250/8250_aspeed_vuart.c | 6 +- > drivers/tty/serial/8250/8250_bcm7271.c | 28 +++--- > drivers/tty/serial/8250/8250_core.c | 12 +-- > drivers/tty/serial/8250/8250_dma.c | 8 +- > drivers/tty/serial/8250/8250_dw.c | 8 +- > drivers/tty/serial/8250/8250_exar.c | 4 +- > drivers/tty/serial/8250/8250_fsl.c | 6 +- > drivers/tty/serial/8250/8250_mtk.c | 8 +- > drivers/tty/serial/8250/8250_omap.c | 52 +++++----- > drivers/tty/serial/8250/8250_pci1xxxx.c | 8 +- > drivers/tty/serial/8250/8250_port.c | 100 ++++++++++---------- > drivers/tty/serial/altera_jtaguart.c | 28 +++--- > drivers/tty/serial/altera_uart.c | 20 ++-- > drivers/tty/serial/amba-pl010.c | 20 ++-- > drivers/tty/serial/amba-pl011.c | 72 +++++++------- > drivers/tty/serial/apbuart.c | 8 +- > drivers/tty/serial/ar933x_uart.c | 26 ++--- > drivers/tty/serial/arc_uart.c | 16 ++-- > drivers/tty/serial/atmel_serial.c | 24 ++--- > drivers/tty/serial/bcm63xx_uart.c | 22 ++--- > drivers/tty/serial/cpm_uart.c | 8 +- > drivers/tty/serial/digicolor-usart.c | 18 ++-- > drivers/tty/serial/dz.c | 32 +++---- > drivers/tty/serial/fsl_linflexuart.c | 26 ++--- > drivers/tty/serial/fsl_lpuart.c | 88 ++++++++--------- > drivers/tty/serial/icom.c | 26 ++--- > drivers/tty/serial/imx.c | 84 ++++++++-------- > drivers/tty/serial/ip22zilog.c | 36 +++---- > drivers/tty/serial/jsm/jsm_neo.c | 4 +- > drivers/tty/serial/jsm/jsm_tty.c | 16 ++-- > drivers/tty/serial/liteuart.c | 20 ++-- > drivers/tty/serial/lpc32xx_hs.c | 26 ++--- > drivers/tty/serial/ma35d1_serial.c | 22 ++--- > drivers/tty/serial/mcf.c | 20 ++-- > drivers/tty/serial/men_z135_uart.c | 8 +- > drivers/tty/serial/meson_uart.c | 30 +++--- > drivers/tty/serial/milbeaut_usio.c | 16 ++-- > drivers/tty/serial/mpc52xx_uart.c | 12 +-- > drivers/tty/serial/mps2-uart.c | 16 ++-- > drivers/tty/serial/msm_serial.c | 38 ++++---- > drivers/tty/serial/mvebu-uart.c | 18 ++-- > drivers/tty/serial/omap-serial.c | 38 ++++---- > drivers/tty/serial/owl-uart.c | 26 ++--- > drivers/tty/serial/pch_uart.c | 10 +- > drivers/tty/serial/pic32_uart.c | 20 ++-- > drivers/tty/serial/pmac_zilog.c | 52 +++++----- > drivers/tty/serial/pxa.c | 30 +++--- > drivers/tty/serial/qcom_geni_serial.c | 8 +- > drivers/tty/serial/rda-uart.c | 34 +++---- > drivers/tty/serial/rp2.c | 20 ++-- > drivers/tty/serial/sa1100.c | 20 ++-- > drivers/tty/serial/samsung_tty.c | 50 +++++----- > drivers/tty/serial/sb1250-duart.c | 12 +-- > drivers/tty/serial/sc16is7xx.c | 40 ++++---- > drivers/tty/serial/serial-tegra.c | 32 +++---- > drivers/tty/serial/serial_core.c | 88 ++++++++--------- > drivers/tty/serial/serial_mctrl_gpio.c | 4 +- > drivers/tty/serial/serial_port.c | 4 +- > drivers/tty/serial/serial_txx9.c | 26 ++--- > drivers/tty/serial/sh-sci.c | 68 ++++++------- > drivers/tty/serial/sifive.c | 16 ++-- > drivers/tty/serial/sprd_serial.c | 30 +++--- > drivers/tty/serial/st-asc.c | 18 ++-- > drivers/tty/serial/stm32-usart.c | 38 ++++---- > drivers/tty/serial/sunhv.c | 28 +++--- > drivers/tty/serial/sunplus-uart.c | 26 ++--- > drivers/tty/serial/sunsab.c | 34 +++---- > drivers/tty/serial/sunsu.c | 46 ++++----- > drivers/tty/serial/sunzilog.c | 42 ++++---- > drivers/tty/serial/timbuart.c | 8 +- > drivers/tty/serial/uartlite.c | 18 ++-- > drivers/tty/serial/ucc_uart.c | 4 +- > drivers/tty/serial/vt8500_serial.c | 8 +- > drivers/tty/serial/xilinx_uartps.c | 56 +++++------ > include/linux/serial_core.h | 91 ++++++++++++++++-- > 76 files changed, 1086 insertions(+), 1007 deletions(-) > > > base-commit: 0bb80ecc33a8fb5a682236443c1e740d5c917d1d >