From nobody Sat Feb 7 12:34:41 2026 Received: from mail-qk1-f170.google.com (mail-qk1-f170.google.com [209.85.222.170]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1CFFA1C6FF6; Wed, 5 Mar 2025 04:30:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.222.170 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741149022; cv=none; b=F+IThzSbemfzs6omCHpOeGoAgto0ylZdFK5wNR8IT61iRtsfp0mQ8U7AhyQab+Zya/hrt4OAAxi1+o+ch5Ei7nV49CXYP1kHYavxWmc1fbDobOaE51MHSepbBQk2CXJwQ2J1LqYFBn0apb4plxEEFhpSA9szxDcRDmGW1SOXwMY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741149022; c=relaxed/simple; bh=gRv7CV35Y+wxD8+twcYg9frzBTRq/XFnU65egWn7k6c=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=b/FvMPiTOh+1LMRyOmh2kQMIh3JEyJ4+243/7Vg+ASmVufOhLBQ2SDKkyzlPAQpezAduluGLL3034pqxx/tezYh+BpQgSHo7EXCi4oUNetYE23vccw8Um2Af/NPpFIx0gJyujvqoQwtgZPgnCnr6+9yxP1kNw1bKLYcm+qDUMrE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=mwT32YtR; arc=none smtp.client-ip=209.85.222.170 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="mwT32YtR" Received: by mail-qk1-f170.google.com with SMTP id af79cd13be357-7c3b63dfebfso314966185a.3; Tue, 04 Mar 2025 20:30:19 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1741149018; x=1741753818; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=lcg5+dUnqHObtyvwEawYvLNi2iYwLJnPZJ0YScHoNmg=; b=mwT32YtRsCkV8ccMrIy1WveoREqBVRQgWn8vdnoUVbLsyax2NfAWcXtte5MYmaZJ89 iDyiO1SGxtvwKzVIldAPNBTc4aLBkzK6anhIQhTdvYdFGj8BO48OwMcxDOWBKiE2uIyC /6aoNW4U8WdMe7yQwSEP3yF4P8p7eBvgpxBuFX6qNSkNE0x5m87kEgS+1NFk+W2u2s4Y 39CSbM74/Ue+QZ6EA5OtKsi6oxNKFXYGC5bzUhkZBUMelWDWaRJlXjE5tcQ7VG7D23Fd ZaAgjOt5i1vhNxWnEwwCRHbkpdnUTeeZtjTN5+aYiUI3+g9c2lk6kWZYjc1yvCcHnkcw c+/w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1741149018; x=1741753818; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=lcg5+dUnqHObtyvwEawYvLNi2iYwLJnPZJ0YScHoNmg=; b=G1YYplDBtaycTRJEahtPwmo9Gg90HedvKd9mnO/7trVysn7h5rz/xhcf/+PHJ7cI/t CblVQfR+U7Ip/Gi3ByqU0bxXoJcRnCVOq9zODWTpWlwrcEJ2uKEt5WKQaSeAdGYreFRN KrQ2TqMsO/8GtvQ94s07fcxxoQlOEETXhL9XOE25ymSVskw/GSSXau0ucVqw3gIDtTNu OgDThJ14udQr60tiFlUiEbu9zW1GW8UyVbuoffLwQve0uArLjpYKUlMgYSx5AdbGyjmy uyBjXHjMG0SEyKd7ASBiD0/+ygsu43bTfzInkxJszXdsAnTvu6rUN3Caon1LdZ8VXY14 DdNg== X-Forwarded-Encrypted: i=1; AJvYcCV/8Y6oZ4SlKvjX8EUv1VToulGXnJSdT95dZco4KylIJJXDo4CG2m6D7Z4XFbO6V7gxG7eYA7swP8YfqMQ=@vger.kernel.org X-Gm-Message-State: AOJu0YyYWl8xnT2TixoN/KLZkjuLGO1Ey9Nd+VI/ouVohqel6HksBsbZ 4F/bYjIXx0AgCope/2iS8Kwy2HFRuySUhLwdEVoOHp1i/7IE/X3utWc7jR3F X-Gm-Gg: ASbGncsriP3c2tkfoAfPRhmT52Vwy8BUfSRayIy5+U4rtl2ErDjJeUoeRHQGcUfjTZw Si5/yPrG6FwpyX6QpqR8T0uqt0w74f4UTSbZQUBEHL6mABOY0HiyJ5VZxfgUu5QAHvCojOIQWoj ByEJffN9WiFyZGQB95Ovab7VKa0u+4Y4Tq9pu9BNHqrD8fg/x9uwlfAoO+bGX4GKKUMOArzw+U6 T7O0a7zNmsMSna0QuWT3DbUd5xsita+7oJ6sRlJfzx/+ZhsLTUCeAjXv0lBCMvqZTbcIcffem3/ tcprBeWDpVFoaAGcaECMxIohF6opPMZytFp5VZoNX0OiRJmPDZ+XtLbqQuSz/vt3u73Gab+8j+q kvntBlpw= X-Google-Smtp-Source: AGHT+IF8N0NTRr6Ym77rQ/OGR9PWcy55U0ei0cNEhjSrmW9NbsJLsCiFF+iQ4Sbm5xWterLY2TrNDA== X-Received: by 2002:a05:620a:6285:b0:7c3:d32a:2b6d with SMTP id af79cd13be357-7c3d8e66d8cmr340642585a.21.1741149018595; Tue, 04 Mar 2025 20:30:18 -0800 (PST) Received: from nerdopolis2.mynetworksettings.com ([2600:4040:5e66:a800:a5b9:4b66:4113:9357]) by smtp.gmail.com with ESMTPSA id af79cd13be357-7c36fee8b4dsm834060785a.15.2025.03.04.20.30.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 04 Mar 2025 20:30:17 -0800 (PST) From: adamsimonelli@gmail.com To: linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, Jiri Slaby , Greg Kroah-Hartman , Andy Shevchenko , Steven Rostedt , John Ogness , Sergey Senozhatsky , Petr Mladek Cc: Adam Simonelli Subject: [PATCH v7 1/3] ttynull: Always initialize console index to -1 Date: Tue, 4 Mar 2025 23:29:28 -0500 Message-ID: <20250305042930.3453265-2-adamsimonelli@gmail.com> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20250305042930.3453265-1-adamsimonelli@gmail.com> References: <20250305042930.3453265-1-adamsimonelli@gmail.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" From: Adam Simonelli This allows ttynull to be considered in console selection. Suggested-by: Petr Mladek Signed-off-by: Adam Simonelli --- drivers/tty/ttynull.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/tty/ttynull.c b/drivers/tty/ttynull.c index 6b2f7208b564..d8b51edde628 100644 --- a/drivers/tty/ttynull.c +++ b/drivers/tty/ttynull.c @@ -57,6 +57,7 @@ static struct tty_driver *ttynull_device(struct console *= c, int *index) static struct console ttynull_console =3D { .name =3D "ttynull", .device =3D ttynull_device, + .index =3D -1, }; =20 static int __init ttynull_init(void) --=20 2.45.2 From nobody Sat Feb 7 12:34:41 2026 Received: from mail-qk1-f171.google.com (mail-qk1-f171.google.com [209.85.222.171]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 516D11C6FE8; Wed, 5 Mar 2025 04:30:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.222.171 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741149023; cv=none; b=aHbQls3jIK6r6VF2Bm6x7yryec3grGPAs17kHoAKt99048vcV6WaJh6BQSdliODlWNRHkCmCkvGI7sciTam7mVWVJX9XVz4jHt0/Xy7v2isndxyD0kOgqfZtpcmycsPoGpTatCURQxyEe8ZS28OrxLjwUenMAjpSEETdMAyYLFs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741149023; c=relaxed/simple; bh=4OU5LuRAPgPJd1aa7qci6p7EFQ2s4059bejSPNDhMvs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=eRuycRoVS2TPL2snzZxedZjkCsMgbFbHYds8BFSC72CG/WHFFPPSulEmeBEveatvXbCpjero0DzQ0iDVor5Bg/wIJ4JxyBe4djndVPTVk2RV87u/0OUFcx6ab9lD0qtixZlzNP/2jx1fUL6G1f7iLx9LgNSsSuZ0UPbSL1Gsm48= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=c7h8Nqvd; arc=none smtp.client-ip=209.85.222.171 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="c7h8Nqvd" Received: by mail-qk1-f171.google.com with SMTP id af79cd13be357-7c081915cf3so830605885a.1; Tue, 04 Mar 2025 20:30:22 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1741149021; x=1741753821; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=XhFFJIc1/5ckE027gEnZNIXa3PHm3cFoR9UkUps3DRA=; b=c7h8Nqvd5aHtXWLHShyQ8EeUIZtOzH5LZTvYGIyLizyId1s1EdpIc05TuNd7egvhsS EFu+ncqT/QDsITmJB/RqAh9BrFEJIXNtGMHPgNkb2IAfMGLHOROpLYTQ4CyL57R+hcgr fxx/P2NRN6vbHJh9j4oqJtnfOYuoW0Dc/4E2bLCPZXptfwOwADr0kbAPH6HBF3S0aCnV ZF/+WrKA6hwGWdYGHzwP0sP0IJ1IbhICMHCppDQAf/4NUgyetU3bghV/IIpqp9IW4JW+ ugxI/1I/xFa3RvtS4LN7UkQE5WQfQ9PsCxkexZz/oF3n+Aqyj1EKBMLTYPe4t2z6iC5k lhLw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1741149021; x=1741753821; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=XhFFJIc1/5ckE027gEnZNIXa3PHm3cFoR9UkUps3DRA=; b=Vr4KBB8RHDEdoIi+SyPJTdV1eENvLgmHpbscnPP0CYeYqs/OUsA25spiTxZLX8pg1a ksx4nL5VdG0eXqcG9EsTA/DfuPQpJ/KAOhmTE/mSr5azP6ZIrfllrivrLsNo6HRu9S5P G0Lol69QkUwNnDfRltJqgjQbLMoQOA4FFr012LEYUqL8zaMAbAb1UJKc3w98BFdXpO38 LXrmqQK5VnVRG2DkeFMpDKjcvT22ZA7+uct329LYOT+kRZQ/dCzqupW0WShImMRZCitc GbdnK6VlM4bCxHm3z9GWYbAfbwAXjWOifbuajMaXRRoBuyIhJCCIQcjsdw8lV0lAv/3Z Y9SQ== X-Forwarded-Encrypted: i=1; AJvYcCUYoJzJy5USjITafKlC0jX5Af2PVH+p5kgzEJgYUjYxzfejfuskjgElMO0ifkMLYGl4MmjKD+eghF/T4lo=@vger.kernel.org X-Gm-Message-State: AOJu0YwHKKq1h+nO2ADGwtrmUFpAXRP1zcLVj7X9ol8xYZW2Cgd+km1o 24wE75LWcM5LA/c89qydQHV8UkdXTgugEq+B6CvLmmk0wBRjPuiQU1N1NhZ/ X-Gm-Gg: ASbGnct2oQMVQ7UlYK4kxm4arliKLiVKA1GW5os08u7bsP+5bOW/KuT8s//5r6dJp8m R47IUFF0gaCuIT1tikL0DagKNynZYtNpRtdapd7BOjwnbfFWUMBrt9cR0IuYetItvJKN+e7G2oD MRIw2LwcPtzmnpJCdBAJ3KhoZbFeM1G++CqZgmkM2EX9/7KDb/psu58ju1uy6kG8zqchmSRaRe5 k7C9Wjezf67/K3n2Ray+9OCGTsTqWR0kL3jr/9yupEPw9KR2WdEXCsrkdNxIatkHeVc4S5D99fY CdEneRYaR11rSr54SQowPKsB8lCj5Y9jUXtIZtgz+5z4A6bXMRGc9oCsixrdpCPHzVhoJgOpneC Wx/ZJKFo= X-Google-Smtp-Source: AGHT+IFnBhrPsbmYSJgkYVZzATggSZ/pMScHhMhbU/lifZR9B8ONrave/pUxII5tEfZtFN7Pu5DKBA== X-Received: by 2002:a05:620a:6883:b0:7c3:d711:6ffb with SMTP id af79cd13be357-7c3d8eb11c7mr285994785a.41.1741149020906; Tue, 04 Mar 2025 20:30:20 -0800 (PST) Received: from nerdopolis2.mynetworksettings.com ([2600:4040:5e66:a800:a5b9:4b66:4113:9357]) by smtp.gmail.com with ESMTPSA id af79cd13be357-7c36fee8b4dsm834060785a.15.2025.03.04.20.30.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 04 Mar 2025 20:30:20 -0800 (PST) From: adamsimonelli@gmail.com To: linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, Jiri Slaby , Greg Kroah-Hartman , Andy Shevchenko , Steven Rostedt , John Ogness , Sergey Senozhatsky , Petr Mladek Cc: Adam Simonelli Subject: [PATCH v7 2/3] ttynull: Add an option to allow ttynull to be used as a console device Date: Tue, 4 Mar 2025 23:29:29 -0500 Message-ID: <20250305042930.3453265-3-adamsimonelli@gmail.com> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20250305042930.3453265-1-adamsimonelli@gmail.com> References: <20250305042930.3453265-1-adamsimonelli@gmail.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" From: Adam Simonelli The new config option, CONFIG_NULL_TTY_DEFAULT_ CONSOLE will allow ttynull to be initialized by console_initcall() and selected as a possible console device. Signed-off-by: Adam Simonelli --- drivers/tty/Kconfig | 15 ++++++++++++++- drivers/tty/ttynull.c | 13 +++++++++++++ 2 files changed, 27 insertions(+), 1 deletion(-) diff --git a/drivers/tty/Kconfig b/drivers/tty/Kconfig index 63a494d36a1f..00ec1acb69ac 100644 --- a/drivers/tty/Kconfig +++ b/drivers/tty/Kconfig @@ -383,7 +383,20 @@ config NULL_TTY available or desired. =20 In order to use this driver, you should redirect the console to this - TTY, or boot the kernel with console=3Dttynull. + TTY, boot the kernel with console=3Dttynull, or enable + CONFIG_NULL_TTY_DEFAULT_CONSOLE. + + If unsure, say N. + +config NULL_TTY_DEFAULT_CONSOLE + bool "Support for console on ttynull" + depends on NULL_TTY=3Dy && !VT_CONSOLE + help + Say Y here if you want the NULL TTY to be used as a /dev/console + device. + + This is similar to CONFIG_VT_CONSOLE, but without the dependency on + CONFIG_VT. It uses the ttynull driver as the system console. =20 If unsure, say N. =20 diff --git a/drivers/tty/ttynull.c b/drivers/tty/ttynull.c index d8b51edde628..67aad3e6f538 100644 --- a/drivers/tty/ttynull.c +++ b/drivers/tty/ttynull.c @@ -96,6 +96,19 @@ static int __init ttynull_init(void) return 0; } =20 +#ifdef CONFIG_NULL_TTY_DEFAULT_CONSOLE +static int __init ttynull_register(void) +{ + if (console_set_on_cmdline) + return 0; + + add_preferred_console("ttynull", 0, NULL); + + return 0; +} +console_initcall(ttynull_register); +#endif + static void __exit ttynull_exit(void) { unregister_console(&ttynull_console); --=20 2.45.2 From nobody Sat Feb 7 12:34:41 2026 Received: from mail-qk1-f181.google.com (mail-qk1-f181.google.com [209.85.222.181]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 76DC51D63C3; Wed, 5 Mar 2025 04:30:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.222.181 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741149027; cv=none; b=PaRXkJfRzbUWluR32k5YC5BcpVVBzl/WE9uVJEXKQ8W7J//Y2kLVJ35khIIBwynMKRhvbuJ0AUohl1/yAxi10HdZKBAyfINVaWvCDh6FwFx9MrUvXAY6aX0gnUfhtMBD0gygE5D4k7tZJ3xTmVm1xRBm27MlUlrV2UYGd1qfCPQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741149027; c=relaxed/simple; bh=/rtDbi7uSjBFCc9+l01/GCl/ObmCJylChTnhbJQIO7M=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Uslsw6rCOjPyYuhbTx0cyADelWQnAmT5w+Yhj7v0VuxTnLIvmSCH514roVwJn+0fdMLYslmFtE0RFXuFYpuZVkIefY1rp8jrUdMTV9Vrz5Hr2crll29Yb1igvAsWxrrBys4h/hadVmrOT7QyNqeNP7l5Vx2niYgcePiiypm/Hxo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=Tmyiaj2/; arc=none smtp.client-ip=209.85.222.181 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Tmyiaj2/" Received: by mail-qk1-f181.google.com with SMTP id af79cd13be357-7be49f6b331so620466785a.1; Tue, 04 Mar 2025 20:30:25 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1741149024; x=1741753824; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=rjB9uUIaqtE9vOEIpWwNSuqq5SDBhNaUIjyLRrZ2+yo=; b=Tmyiaj2/mhLpZxRsAMjLBcoO5YuNxUrxg9lyn/K1yVLxk/DGqfqU2UvVXfeYtTKWDh BQoJxaTw+J84JrwxfKyXWP8KPOVaPmXjVDPngbNuGUwHtQ9nC1Dgz5bEsZ5shhChxQT8 BoIYXO9/2Srzjbcljfj/NM2uNqPMoLnBZzrXwVBtiHW3AvlMNmqwCT1SGW0Tal1rPX1x UbXGdlhMmTVWO1JeXrRG0FW2FHaXoM/PK9kydouxqKEalNgGeY+XdOk0XOzXLfG7onvF Feh73XekPVR5NpvQwwtONVH4q+XUX+nmiIkZrazwHD+3EWFr9wxRKVwvspec0HhaiV7k 1jQw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1741149024; x=1741753824; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=rjB9uUIaqtE9vOEIpWwNSuqq5SDBhNaUIjyLRrZ2+yo=; b=QoUjGHElj7pNpxU9KoHf/B0pcff+rdc5MRchmSB63/gaRlNWiOx5UmPNPtnhz9hbUK 4KA1HSBwu9bBlaqDFmxFtl1Q/tooN+o3DJDYWuhgRl8p/89cbQqvieAfxL12lkRhoNuI Com3fyC9y5C1daiaYCzqaz1HVX6KNz85xes1mvCUJtlPpLbMq6OoHEKo5QO9Kik/WfaC pWdr29eT9Bm9yzg7sNjMXXd2o2ILfy+3Be4CiHqmDWOAvcWLRKKua1CZqbw2Eqe1h4T9 MOQt8PZULvWq6m3BZJ9MMhMZKy2JHbT6Zc1BJzMmuIlGJTcUnoeaPDqqHVFHPdCg8nlQ fdTg== X-Forwarded-Encrypted: i=1; AJvYcCX6GMx6ICk3h4emNmbnZynGCz5pSret22whjMf9e5gYgtSuzOd3ClomLIHmPKVxci4YbBQqmyUcQQPpgDY=@vger.kernel.org X-Gm-Message-State: AOJu0YxYcLlBSZEXi61UFxDbeHfok57wseyhWSzYms5XrGGlipn+n3JW D9fMCeNYQ6SZlJEXutSAJRN6v+IM6XawqYwAfDred9bXulPKCgNGeHDky19u X-Gm-Gg: ASbGncsBlbXWpJJp2fDVeDgCJLVcu4edLaMEiHGHjIMUTi+uR8c6zEQfAovcqk6rP/s fhsOyivYjvbMvqRYWL0QfvTmwsj0LP1e8UjYrleQsw8EzOFwOYT5miSDPNNKVXGPPpaiKVlwH2L l1wrsXLhnedIdhQFRqD70GYpCcJSsntmsW5yQbr0JdBZNxs1u23LTn3E9+n3EqFtoelQHgrqppq Bmi1Ru25RMY7LKFhsAaa3CaJ9LMWRSYRrQESdA4WPSTVWGRS7AX7i2RZATpSUGzuoSf5A+W2+cc hCAwCKBacIqV7G1VE5+upuwqz5V05s+V5GYKPoucsRvU4HEAak4s8PBnuDhBjLZXMBa3k8e5D8v +I6lmPbI= X-Google-Smtp-Source: AGHT+IGWDx0RkZd6Nu9XMl3P81+xGGY29EFnXdhoJHvCCiaa+rmUCdY6b51hp0aq9gPRkLbOBpWKyw== X-Received: by 2002:a05:620a:8908:b0:7c3:d45b:c0bc with SMTP id af79cd13be357-7c3d8ee1838mr399822985a.36.1741149023860; Tue, 04 Mar 2025 20:30:23 -0800 (PST) Received: from nerdopolis2.mynetworksettings.com ([2600:4040:5e66:a800:a5b9:4b66:4113:9357]) by smtp.gmail.com with ESMTPSA id af79cd13be357-7c36fee8b4dsm834060785a.15.2025.03.04.20.30.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 04 Mar 2025 20:30:22 -0800 (PST) From: adamsimonelli@gmail.com To: linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, Jiri Slaby , Greg Kroah-Hartman , Andy Shevchenko , Steven Rostedt , John Ogness , Sergey Senozhatsky , Petr Mladek Cc: Adam Simonelli Subject: [PATCH v7 3/3] tty: Change order of ttynull to be linked sooner if enabled as a console. Date: Tue, 4 Mar 2025 23:29:30 -0500 Message-ID: <20250305042930.3453265-4-adamsimonelli@gmail.com> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20250305042930.3453265-1-adamsimonelli@gmail.com> References: <20250305042930.3453265-1-adamsimonelli@gmail.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" From: Adam Simonelli If CONFIG_NULL_TTY_DEFAULT_CONSOLE is enabled, and CONFIG_VT is disabled, ttynull will become the default primary console device, based on the link order. Many distributions ship with CONFIG_VT enabled. On tested desktop hardware if CONFIG_VT is disabled, the default console device falls back to /dev/ttyS0 instead of /dev/tty. This could cause issues in user space, and hardware problems: 1. The user space issues include the case where /dev/ttyS0 is disconnected, and the TCGETS ioctl, which some user space libraries use as a probe to determine if a file is a tty, is called on /dev/console and fails. Programs that call isatty() on /dev/console and get an incorrect false value may skip expected logging to /dev/console. 2. The hardware issues include the case if a user has a science instrument or other device connected to the /dev/ttyS0 port, and they were to upgrade to a kernel that is disabling the CONFIG_VT option, kernel logs will then be sent to the device connected to /dev/ttyS0 unless they edit their kernel command line manually. The new CONFIG_NULL_TTY_CONSOLE option will give users and distribution maintainers an option to avoid this. Disabling CONFIG_VT and enabling CONFIG_NULL_TTY_CONSOLE will ensure the default kernel console behavior is not dependant on hardware configuration by default, and avoid unexpected new behavior on devices connected to the /dev/ttyS0 serial port. Signed-off-by: Adam Simonelli --- drivers/tty/Makefile | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/drivers/tty/Makefile b/drivers/tty/Makefile index 07aca5184a55..7d0414dc31ed 100644 --- a/drivers/tty/Makefile +++ b/drivers/tty/Makefile @@ -11,6 +11,12 @@ obj-$(CONFIG_N_HDLC) +=3D n_hdlc.o obj-$(CONFIG_N_GSM) +=3D n_gsm.o =20 obj-y +=3D vt/ + +# If ttynull is configured to be a console by default, ensure that it is l= inked +# earlier before a real one is selected. +obj-$(CONFIG_NULL_TTY_DEFAULT_CONSOLE) \ + +=3D ttynull.o + obj-$(CONFIG_HVC_DRIVER) +=3D hvc/ obj-y +=3D serial/ obj-$(CONFIG_SERIAL_DEV_BUS) +=3D serdev/ @@ -20,7 +26,13 @@ obj-$(CONFIG_AMIGA_BUILTIN_SERIAL) +=3D amiserial.o obj-$(CONFIG_MOXA_INTELLIO) +=3D moxa.o obj-$(CONFIG_MOXA_SMARTIO) +=3D mxser.o obj-$(CONFIG_NOZOMI) +=3D nozomi.o + +# If ttynull is enabled, but not as a boot console, it is linked and used = later +# after the real ones. +ifneq ($(CONFIG_NULL_TTY_DEFAULT_CONSOLE),y) obj-$(CONFIG_NULL_TTY) +=3D ttynull.o +endif + obj-$(CONFIG_SYNCLINK_GT) +=3D synclink_gt.o obj-$(CONFIG_PPC_EPAPR_HV_BYTECHAN) +=3D ehv_bytechan.o obj-$(CONFIG_GOLDFISH_TTY) +=3D goldfish.o --=20 2.45.2