From nobody Thu Dec 18 07:21:07 2025 Received: from mail5.25mail.st (mail5.25mail.st [74.50.62.9]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E82EE52F8D; Wed, 27 Mar 2024 11:01:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.50.62.9 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711537320; cv=none; b=JNX585dxn1/aPhaBmZKuLRtzdUt9L9UdmPh65niJe5grE8HBQLpaYjzEKILG1y31hp89mLZKftvNCMpSkeG/8OliVO+hnBFCftG2/fNx5d3yiexwfJCEamg95Cdwm6qL/T0wn1/IRsyAnGRtE2ke7CqmAX8PUk3Ql6ni1J7/ty0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711537320; c=relaxed/simple; bh=mvzC3zJ36JM//DA+DACooA2x2bGYxkLRQfyMbLITm/E=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=uBeD9R/b40L66ElScTZdzB9p4DUUSKEV/Y0XEo0txaGNIHtb1vwU+Rw0J85HbWGTgT9nR7vSDIrjGpw7b3Zz0SaLcSigLoF4/qJIrf6ieHXdTyymEHZc8EIJ2UXPeuyXKhwL1+Qhi7x1Y2oR4vAlbsR0E87ch/jrejjAlCQEuA4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=atomide.com; spf=fail smtp.mailfrom=atomide.com; dkim=pass (2048-bit key) header.d=atomide.com header.i=@atomide.com header.b=CA0dYUg3; arc=none smtp.client-ip=74.50.62.9 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=atomide.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=atomide.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=atomide.com header.i=@atomide.com header.b="CA0dYUg3" Received: from localhost (91-158-86-216.elisa-laajakaista.fi [91.158.86.216]) by mail5.25mail.st (Postfix) with ESMTPSA id 9776F6088D; Wed, 27 Mar 2024 11:01:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=atomide.com; s=25mailst; t=1711537315; bh=mvzC3zJ36JM//DA+DACooA2x2bGYxkLRQfyMbLITm/E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CA0dYUg3biS+q1OX6qK1hkWT+3mhtWw2cOyavcwJImJMRWYDTeZlTHtHEPtZNmq1v nNxbykDaufV+z+poE9/vLepveY3UMOYZHSJYMNyY1pQW1dCtt9Jw3As9nLWtT/BDvL x0hUvFYZOA44RocFU7LKdrmYl9upj60E85uvmSd7UIWKXRPZWIkz6NfgIhiIVNGHCG hDSpf9ax0jrBvwKM9aESAF6ek7t0LIYQE+fmD5w8Or7h8wjf6LunVsVDeSLu7G8DFf Dm0byh5HZVXFnEojkiVGYbLYWXCYW18gvq0VOFkBHop+Zv17OoodI3PdMNFYPVLm3i 5tqwOzv1jaaYA== From: Tony Lindgren To: Greg Kroah-Hartman , Jiri Slaby , Jonathan Corbet , Petr Mladek , Steven Rostedt , John Ogness , Sergey Senozhatsky Cc: "David S . Miller" , Andy Shevchenko , Dhruva Gole , =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= , Johan Hovold , Sebastian Andrzej Siewior , Vignesh Raghavendra , linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, Sebastian Reichel , linux-doc@vger.kernel.org Subject: [PATCH v7 1/7] printk: Save console options for add_preferred_console_match() Date: Wed, 27 Mar 2024 12:59:35 +0200 Message-ID: <20240327110021.59793-2-tony@atomide.com> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240327110021.59793-1-tony@atomide.com> References: <20240327110021.59793-1-tony@atomide.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Driver subsystems may need to translate the preferred console name to the character device name used. We already do some of this in console_setup() with a few hardcoded names, but that does not scale well. The console options are parsed early in console_setup(), and the consoles are added with __add_preferred_console(). At this point we don't know much about the character device names and device drivers getting probed. To allow driver subsystems to set up a preferred console, let's save the kernel command line console options. To add a preferred console from a driver subsystem with optional character device name translation, let's add a new function add_preferred_console_match(). This allows the serial core layer to support console=3DDEVNAME:0.0 style hardware based addressing in addition to the current console=3DttyS0 style naming. And we can start moving console_setup() character device parsing to the driver subsystem specific code. We use a separate array from the console_cmdline array as the character device name and index may be unknown at the console_setup() time. And eventually there's no need to call __add_preferred_console() until the subsystem is ready to handle the console. Adding the console name in addition to the character device name, and a flag for an added console, could be added to the struct console_cmdline. And the console_cmdline array handling could be modified accordingly. But that complicates things compared saving the console options, and then adding the consoles when the subsystems handling the consoles are ready. Co-developed-by: Andy Shevchenko Signed-off-by: Tony Lindgren --- include/linux/printk.h | 3 + kernel/printk/Makefile | 2 +- kernel/printk/conopt.c | 146 ++++++++++++++++++++++++++++++++ kernel/printk/console_cmdline.h | 6 ++ kernel/printk/printk.c | 14 ++- 5 files changed, 167 insertions(+), 4 deletions(-) create mode 100644 kernel/printk/conopt.c diff --git a/include/linux/printk.h b/include/linux/printk.h --- a/include/linux/printk.h +++ b/include/linux/printk.h @@ -60,6 +60,9 @@ static inline const char *printk_skip_headers(const char = *buffer) #define CONSOLE_LOGLEVEL_DEFAULT CONFIG_CONSOLE_LOGLEVEL_DEFAULT #define CONSOLE_LOGLEVEL_QUIET CONFIG_CONSOLE_LOGLEVEL_QUIET =20 +int add_preferred_console_match(const char *match, const char *name, + const short idx); + extern int console_printk[]; =20 #define console_loglevel (console_printk[0]) diff --git a/kernel/printk/Makefile b/kernel/printk/Makefile --- a/kernel/printk/Makefile +++ b/kernel/printk/Makefile @@ -1,5 +1,5 @@ # SPDX-License-Identifier: GPL-2.0-only -obj-y =3D printk.o +obj-y =3D printk.o conopt.o obj-$(CONFIG_PRINTK) +=3D printk_safe.o nbcon.o obj-$(CONFIG_A11Y_BRAILLE_CONSOLE) +=3D braille.o obj-$(CONFIG_PRINTK_INDEX) +=3D index.o diff --git a/kernel/printk/conopt.c b/kernel/printk/conopt.c new file mode 100644 --- /dev/null +++ b/kernel/printk/conopt.c @@ -0,0 +1,146 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Kernel command line console options for hardware based addressing + * + * Copyright (C) 2023 Texas Instruments Incorporated - https://www.ti.com/ + * Author: Tony Lindgren + */ + +#include +#include +#include +#include + +#include + +#include "console_cmdline.h" + +/* + * Allow longer DEVNAME:0.0 style console naming such as abcd0000.serial:0= .0 + * in addition to the legacy ttyS0 style naming. + */ +#define CONSOLE_NAME_MAX 32 + +#define CONSOLE_OPT_MAX 16 +#define CONSOLE_BRL_OPT_MAX 16 + +struct console_option { + char name[CONSOLE_NAME_MAX]; + char opt[CONSOLE_OPT_MAX]; + char brl_opt[CONSOLE_BRL_OPT_MAX]; + u8 has_brl_opt:1; +}; + +/* Updated only at console_setup() time, no locking needed */ +static struct console_option conopt[MAX_CMDLINECONSOLES]; + +/** + * console_opt_save - Saves kernel command line console option for driver = use + * @str: Kernel command line console name and option + * @brl_opt: Braille console options + * + * Saves a kernel command line console option for driver subsystems to use= for + * adding a preferred console during init. Called from console_setup() onl= y. + * + * Return: 0 on success, negative error code on failure. + */ +int __init console_opt_save(const char *str, const char *brl_opt) +{ + struct console_option *con; + size_t namelen, optlen; + const char *opt; + int i; + + namelen =3D strcspn(str, ","); + if (namelen =3D=3D 0 || namelen >=3D CONSOLE_NAME_MAX) + return -EINVAL; + + opt =3D str + namelen; + if (*opt =3D=3D ',') + opt++; + + optlen =3D strlen(opt); + if (optlen >=3D CONSOLE_OPT_MAX) + return -EINVAL; + + for (i =3D 0; i < MAX_CMDLINECONSOLES; i++) { + con =3D &conopt[i]; + + if (con->name[0]) { + if (!strncmp(str, con->name, namelen)) + return 0; + continue; + } + + /* + * The name isn't terminated, only opt is. Empty opt is fine, + * but brl_opt can be either empty or NULL. For more info, see + * _braille_console_setup(). + */ + strscpy(con->name, str, namelen + 1); + strscpy(con->opt, opt, CONSOLE_OPT_MAX); + if (brl_opt) { + strscpy(con->brl_opt, brl_opt, CONSOLE_BRL_OPT_MAX); + con->has_brl_opt =3D 1; + } + + return 0; + } + + return -ENOMEM; +} + +static struct console_option *console_opt_find(const char *name) +{ + struct console_option *con; + int i; + + for (i =3D 0; i < MAX_CMDLINECONSOLES; i++) { + con =3D &conopt[i]; + if (!strcmp(name, con->name)) + return con; + } + + return NULL; +} + +/** + * add_preferred_console_match - Adds a preferred console if a match is fo= und + * @match: Expected console on kernel command line, such as console=3DDEVN= AME:0.0 + * @name: Name of the console character device to add such as ttyS + * @idx: Index for the console + * + * Allows driver subsystems to add a console after translating the command + * line name to the character device name used for the console. Options are + * added automatically based on the kernel command line. Duplicate preferr= ed + * consoles are ignored by __add_preferred_console(). + * + * Return: 0 on success, negative error code on failure. + */ +int add_preferred_console_match(const char *match, const char *name, + const short idx) +{ + struct console_option *con; + char *brl_opt =3D NULL; + + if (!match || !strlen(match) || !name || !strlen(name) || + idx < 0) + return -EINVAL; + + con =3D console_opt_find(match); + if (!con) + return -ENOENT; + + /* + * See __add_preferred_console(). It checks for NULL brl_options to set + * the preferred_console flag. Empty brl_opt instead of NULL leads into + * the preferred_console flag not set, and CON_CONSDEV not being set, + * and the boot console won't get disabled at the end of console_setup(). + */ + if (con->has_brl_opt) + brl_opt =3D con->brl_opt; + + console_opt_add_preferred_console(name, idx, con->opt, brl_opt); + + return 0; +} diff --git a/kernel/printk/console_cmdline.h b/kernel/printk/console_cmdlin= e.h --- a/kernel/printk/console_cmdline.h +++ b/kernel/printk/console_cmdline.h @@ -2,6 +2,12 @@ #ifndef _CONSOLE_CMDLINE_H #define _CONSOLE_CMDLINE_H =20 +#define MAX_CMDLINECONSOLES 8 + +int console_opt_save(const char *str, const char *brl_opt); +int console_opt_add_preferred_console(const char *name, const short idx, + char *options, char *brl_options); + struct console_cmdline { char name[16]; /* Name of the driver */ diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -383,9 +383,6 @@ static int console_locked; /* * Array of consoles built from command line options (console=3D) */ - -#define MAX_CMDLINECONSOLES 8 - static struct console_cmdline console_cmdline[MAX_CMDLINECONSOLES]; =20 static int preferred_console =3D -1; @@ -2497,6 +2494,10 @@ static int __init console_setup(char *str) if (_braille_console_setup(&str, &brl_options)) return 1; =20 + /* Save the console for driver subsystem use */ + if (console_opt_save(str, brl_options)) + return 1; + /* * Decode str into name, index, options. */ @@ -2527,6 +2528,13 @@ static int __init console_setup(char *str) } __setup("console=3D", console_setup); =20 +/* Only called from add_preferred_console_match() */ +int console_opt_add_preferred_console(const char *name, const short idx, + char *options, char *brl_options) +{ + return __add_preferred_console(name, idx, options, brl_options, true); +} + /** * add_preferred_console - add a device to the list of preferred consoles. * @name: device name --=20 2.44.0