From patchwork Tue Mar 4 03:54:45 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Adam Simonelli X-Patchwork-Id: 870456 Received: from mail-qt1-f170.google.com (mail-qt1-f170.google.com [209.85.160.170]) (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 7EA111F12E7; Tue, 4 Mar 2025 03:55:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.160.170 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741060502; cv=none; b=CX0ZfOp0K+SlFds655DbaS+5c2QUH8CqWMy+EIt6FrG+1wxoyPVXY/r688DBTvQc1/AG1JTHckfFammMsBXBOlWLNcKolhD1vlA879/MT2uE/Xyf1dYTZqxrRCyzOBgE8D297ru0VkVTnyo0HqNMkJ5vnfKpy4AmnSIgtW2N7aM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741060502; c=relaxed/simple; bh=aMuLi0cFdrxkp4efrxFeE79RPAtt10/3L8Ja4bvdE+4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=iVJYRJFxwCjGlhD6yP9a64+MGtHQWcJv9xPgFkHrbZwuv8hRecyM+TyH16Ry0jX5O6PsHbhdd44aXTUWvO/5oNRkyG0UbyWXZ1UQUz/ZjQpZdTEw/m/sk0KqN58s4SZdQDb1rwEIJm4rbbI31LVjx9LrIvo4U/ij2/4qQS6o4NQ= 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=RiB155rh; arc=none smtp.client-ip=209.85.160.170 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="RiB155rh" Received: by mail-qt1-f170.google.com with SMTP id d75a77b69052e-47220d28138so72767621cf.3; Mon, 03 Mar 2025 19:55:01 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1741060500; x=1741665300; 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=VNAkXef11zdfcgjeJ3kpSPOXc080QlYH+4o4TcrHlyw=; b=RiB155rhpf2Nat+D3Zn2jMfuO/TW/Y3LMqyQl9okCoxfv4oXtgNAl7vCMmReScx+iw iB/PPFD3UCYGFVt12BzL7uMd/laSQkgxSZRsH8x1i8uO4D/Df9bQLEtpRmsj2coNdrUJ 0qrqVOle/QJY9Yf6Qmvr3yeSDN0z3BMXSI3sA/tYLlqvG+9ebDl/WQ2RVrOxwOShqQiR KXx9p76ON+oSXH1MNvWdt33F2mJwzJdqQEHomHCBkPkiajf+zikGvM/WjGNTqQutD3LT lh6LfgBX0ORGjGg05Axm+kbPd6PHZc66t1UbqY/aL0yl5ZZFljK7JMcDEaTC9Al9+CUv Disw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1741060500; x=1741665300; 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=VNAkXef11zdfcgjeJ3kpSPOXc080QlYH+4o4TcrHlyw=; b=hgOs0FH4UPDNcd3/b6nz6hST84t/p8BdppTariUulYiATGfCsek9raJbH6D5S1jmz1 xjJCAuPH3jH1eRGyXSyHVUTBSjNWpI5suGCTMK5++UestUfwG2dpU+qYecJV60cuH3CE qZhia9DI4eVSWwBtArRWX/lMf+YhIZRRYs1+au0F1AZOyLs9Dkv/1wE++WGCqVaIlOTn I8INUgF8GMXxlJW8beWFAFzd6AlDYTyxu0L0PNOgr+M7APzCtL2p8g/DX4M2q1E92lUD 1JIXxjz6DnUvmm61UNeGvU8aWfjPNKsd1s3g96QejrdDzwzcPoejkVBm7EGwpQUIELxs VLLQ== X-Forwarded-Encrypted: i=1; AJvYcCUv9olJr0vQNiu3LA5g2u8FBuws039rB3Nr3rkaV0M5H5tv3Isdp0y3wcLLKkuQPmsX4w+CGKFEKX//Amw=@vger.kernel.org X-Gm-Message-State: AOJu0Yz6OajyzUuFhwApSi9NatTp/8zYHf0NlB5lCwmgI3ZCiBp4voG0 JT1zUQj9+eXGxpyYRQqr4XVRLbgrDBOtP/liXkzFwP+Dei07BZl9ho4oKvEc X-Gm-Gg: ASbGncu9elUEL+93JSrb0PniknMda+GVoyvW6IJUREXneR/nxXBQZ/38IDw9TM6s3v2 s2MChN0/fch/XSWe8LERIYH4IhfsppyiRwnK9CrFQugQBs38pBFf0lVTJC4Rj5+UHUyZUnGxA80 dr25kaUhymoiZV2F8mTyBUF0c6IEiGbseiW8G3A6egBDSjCWzPiHA3DMVdjyonGFI2nwBJH7ayb vE1p8cVZNf78qNCrp/Fmf7zWEc/YaJCwy63XoThqz29s3hIO5GANH3Zh/TPDM3CtzFiMm4A4FP/ gZUaTj0W6Zf9KWtSulyWKW9U65HrS+nKTmuQ2EyqlHGHbGUOKh9Wn2nMf9/i7bGz3urFUnqf77j WuNxPo8Q= X-Google-Smtp-Source: AGHT+IEJRv1Z1puHuTTDS5BASBzewCEEpv3HGY0UCNruNC1c4UgHWBCzRGInQGoqxonwoxHSrJHP6g== X-Received: by 2002:ac8:5a09:0:b0:472:744:e272 with SMTP id d75a77b69052e-474bc0e1912mr231157041cf.33.1741060500153; Mon, 03 Mar 2025 19:55:00 -0800 (PST) Received: from nerdopolis2.mynetworksettings.com ([2600:4040:5e66:a800:745f:1ed4:1113:4077]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-474691a1f2csm67567041cf.13.2025.03.03.19.54.58 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 03 Mar 2025 19:54:59 -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 v6 1/3] ttynull: Always initialize console index to -1 Date: Mon, 3 Mar 2025 22:54:45 -0500 Message-ID: <20250304035447.3138221-2-adamsimonelli@gmail.com> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20250304035447.3138221-1-adamsimonelli@gmail.com> References: <20250304035447.3138221-1-adamsimonelli@gmail.com> Precedence: bulk X-Mailing-List: linux-serial@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Adam Simonelli 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 = { .name = "ttynull", .device = ttynull_device, + .index = -1, }; static int __init ttynull_init(void) From patchwork Tue Mar 4 03:54:46 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Adam Simonelli X-Patchwork-Id: 870776 Received: from mail-qt1-f177.google.com (mail-qt1-f177.google.com [209.85.160.177]) (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 9F0B91F30BE; Tue, 4 Mar 2025 03:55:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.160.177 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741060506; cv=none; b=fqC+o+gTc5ZzhsSUGrvtZrJXfjl11wkSr3zDgbakb605P8LtSAnuXmBt0yPCUglZ3GzEQyTyZZ0/UfNB+VWuiMLZE95KDYNTc7XMOS3VrTzicVcil9OLw42uzceRO2uhG2IfJMY/+FJvDT5XkwleoSiIsY1YV/+MlUWCaJjRZvM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741060506; c=relaxed/simple; bh=lERtH19jid+LO+y/8+3N2dc3zBqsli+R2bMI9zoxhww=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=AbhiKYDmkOHV9Q04FCoBQ+Chy0bsvKf5hGn5Q7msdX8CaT9nXjTNxJU0uUNnTbypbysmME1U15qNLFWfflQIA6Z3kNOD6bn2epMeRg0ffD14z39EO3pI2oHyhZkr62zFpzqk3QKpjW8zQR2mA2hp4fSn7+O+fCLzqSBNWa9raus= 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=SHEOnNnM; arc=none smtp.client-ip=209.85.160.177 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="SHEOnNnM" Received: by mail-qt1-f177.google.com with SMTP id d75a77b69052e-471fabc5bf5so24127811cf.3; Mon, 03 Mar 2025 19:55:04 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1741060503; x=1741665303; 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=Ie5BUWJem9d+IyUYFdQ1/YspxsAeO3qZHjwNy/H0VKQ=; b=SHEOnNnM9irNPLNM9UUo66MomCQudMQx9WfapHqyoypc2SJOiNJRf0EeIvB9WzSC5L yKejtI9Sdri3lmo552XPt/Y1aa5cThAiKXrakQpH1ROK6Rf/pkeKqTt0O5d+e4agyUYt mCSJp9jH6EnWq3EnA8dTz/5YglRdRBXsJNOicwY3+/oW/ZzoHhbeRR344AI4Va+CTqpR wqrEEf+ps8jLfCKMKf+YqG3AXmihuwgC12goRYy2VspDkYPrlTc/5eUx2DPse9JCq0HZ 7/g8T1Ls6NVfDvUZFbpXuRMz9FPHSiiaof2l47nK2K9Mjf+eDnQhpKnJP2HWsTd+ir61 JJ6g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1741060503; x=1741665303; 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=Ie5BUWJem9d+IyUYFdQ1/YspxsAeO3qZHjwNy/H0VKQ=; b=UPcDDxDYei6eNSIWwB8g98GI+cVCnkAnCAdmGl892r1tRDncfJpkCBU/QIBZTvqEm6 qhKzm/F2ied98cqxEn+uXIlAeO7rIM+4x2b5inOyD7SPZrnkL5hNYFSMTrHZa3V4oyR3 ru0zyFXt5jOvYJ2NnApL74HVXWEsYnEy6oabxAFcYo/mudTPakpA59LzLzS/+hBAqMMC HCbUMlnv2KjqYlQOH9nAWYCmkKqvw8uE6bqJqekZ5CaTuvOnspvM1W7U08BLaVMgVZW8 d35s7q41inxBwaA0uSiC0N8QddJsNoxbcWrHhEAQKM40CuTeRwjMlnUAwpOIqbQL4K68 KjYg== X-Forwarded-Encrypted: i=1; AJvYcCVVpCfpZJfcL0OykXipDOFIBJt6O9LHMUMVP1YFXsl9zo5jVSOSMIA/vzRYW5vKKDPRTIsnIy3KV1ffius=@vger.kernel.org X-Gm-Message-State: AOJu0Yxp/qaygyG8FmnYsT19OCo7wBy5WXSEXZ2x1dkw5fv56ax3NPhc oFfoYRohNyeyoCD5E6+dMFq4Z29rRuiIzk/5RXpdUO6j0lJUts2Yh1LZL6T9 X-Gm-Gg: ASbGnctgBFKPTiR/rcUwWYglYiN5Hwn1/2wSpZ7wc9FajY4SC694wv3yuYLkbGwF0b1 8Ryh/emte78fSUZr0ZYWGU5FmxauQCpER1QQac3nXBiIned0cl/4R+8202q6YlNdBBjOdzjxzA2 VUzT+oRU9PwCl/MPTjFzgo+ZUa3ehw53v3aDIYT7mTnqwAsdLSRr1kvUr8D/Gpyfs2WzXBLtB3q SfM4TJy/4C8Uspq8+vco86zj2pwtEfWddrJa1vGlz45THrBJ+IwK9CXUCVBh1xeXkHYXc/+nqA2 sclkDyCneMnobCeQid1Yz/CjD1tUcHAmPmZNBfCNT1RYNIwzcSdkiNCsjwHVDh7kZZHjKGX6VUp gxnU6ROE= X-Google-Smtp-Source: AGHT+IGzkCf+odoTMbwNVMmYnlLG+yxs/PQOgVnpMSX3DQlX4FrPEXs3vPJw08soCZANFkrZtRx3sw== X-Received: by 2002:a05:622a:20a:b0:471:8d66:cd68 with SMTP id d75a77b69052e-474bc0554ddmr207463321cf.3.1741060503308; Mon, 03 Mar 2025 19:55:03 -0800 (PST) Received: from nerdopolis2.mynetworksettings.com ([2600:4040:5e66:a800:745f:1ed4:1113:4077]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-474691a1f2csm67567041cf.13.2025.03.03.19.55.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 03 Mar 2025 19:55:02 -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 v6 2/3] ttynull: Add an option to allow ttynull to be used as a console device Date: Mon, 3 Mar 2025 22:54:46 -0500 Message-ID: <20250304035447.3138221-3-adamsimonelli@gmail.com> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20250304035447.3138221-1-adamsimonelli@gmail.com> References: <20250304035447.3138221-1-adamsimonelli@gmail.com> Precedence: bulk X-Mailing-List: linux-serial@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 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 | 11 +++++++++++ 2 files changed, 25 insertions(+), 1 deletion(-) diff --git a/drivers/tty/Kconfig b/drivers/tty/Kconfig index 63a494d36a1f..868aec2ccbb3 100644 --- a/drivers/tty/Kconfig +++ b/drivers/tty/Kconfig @@ -383,7 +383,20 @@ config NULL_TTY available or desired. In order to use this driver, you should redirect the console to this - TTY, or boot the kernel with console=ttynull. + TTY, boot the kernel with console=ttynull, 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=y && !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. If unsure, say N. diff --git a/drivers/tty/ttynull.c b/drivers/tty/ttynull.c index d8b51edde628..cb1e363b726d 100644 --- a/drivers/tty/ttynull.c +++ b/drivers/tty/ttynull.c @@ -96,6 +96,17 @@ static int __init ttynull_init(void) return 0; } +#ifdef CONFIG_NULL_TTY_DEFAULT_CONSOLE +static int __init ttynull_register(void) +{ + if (!console_set_on_cmdline) + add_preferred_console("ttynull", 0, NULL);; + + return 0; +} +console_initcall(ttynull_register); +#endif + static void __exit ttynull_exit(void) { unregister_console(&ttynull_console); From patchwork Tue Mar 4 03:54:47 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Adam Simonelli X-Patchwork-Id: 870455 Received: from mail-qt1-f176.google.com (mail-qt1-f176.google.com [209.85.160.176]) (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 B6F9B1F4169; Tue, 4 Mar 2025 03:55:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.160.176 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741060509; cv=none; b=pZhMkOJt895AyC9cOd4B2hfHDlMtUsMViTIxNIF5Q13zg4ndXi8MsNAqgkNYaoDs4JrcHfDE8Bf54zhStYBz6pMpu2YZQmHcP5OQ+6AxawW35cTemg3QLwOTOtN89oGKSzJ7ZRb1u8GVg212pUmzDebwVm0QKzyot3eW90x7tzM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741060509; c=relaxed/simple; bh=K2JMcePkguomNk533rxGnSo7HEuNE+HYU/PkTSIxr0s=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=HwqCGEsN6fNyYBjzJXUNLO/NAUIu10Sp8QHJAOa/WjMtT8tN7jqfneMvs4djJ69525oDFuXscK20qKxqG4VcuJwMvM9eo2hdNQ5xukJn1qnQCaGz7DXesew1QnrBRgu65Reu60YQ+oLQe4B/C1gZdqaRqgyY+8HViY5dUGGX75s= 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=AuSLG6pn; arc=none smtp.client-ip=209.85.160.176 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="AuSLG6pn" Received: by mail-qt1-f176.google.com with SMTP id d75a77b69052e-47220d28138so72768331cf.3; Mon, 03 Mar 2025 19:55:07 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1741060506; x=1741665306; 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=GdcrE3LdnQVgeO5HL+/GJUF9iIqr/dYjf5g3HkcSy6c=; b=AuSLG6pn/6juVZZWf0ja6SbSZE/5t56qYuGrjV1UUsN9l3havmN35uCKug+yo8npqE wqq+PSgL0cl3kFjAxnf3SvVvwktF42IF4Xnmon52WhgAvH1cbAw1SXI+cQeccnmIbj8F MhfHBs1rrEb+/8C09ETQBcAd/70UxC3LYQ1nv643w7ZUp0PMn4Prfx7VS4PyXxl/92go Pi8HKWzEVPTyahwrniPMscyT3+W9BvbzknQMnL06wcRjZ6yUBsn4UZDtoo76UCXv86pn lR4DkgJ41lnsePLNUattMgqwolInJ/O0wRjZyRVZPHvnrokTrF+/dOmM9N3nceg4ps4G YOxg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1741060506; x=1741665306; 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=GdcrE3LdnQVgeO5HL+/GJUF9iIqr/dYjf5g3HkcSy6c=; b=JZv93JpSm1eqBVSLBYVl9+2wf6tMsnZwdQwLrXl1+tZVabNNf8rVs/8Vw06cZajt0v /LdLUKD53jutG5dOdLx8mkQip9TpR5YVnN4KnChrJ0hUtSk5ZrA3qKX1W0h8/q40m6N0 LAnwz1Lsk0qRghVXJu8c+zrEa0O34UsKlpPKIHoLizAApeDjVyT6N9qWGwjkd2MwQ2l5 Y1dxxcX22YqJ+VL8ObfQXXVGQXl08FlAwNjprQLR8qk+SBsd35Lv2oz79s8SD9mnKOe1 kk1gr1WH0VT/v2flmUP02dEQ4rP3R+A8Dzh4DjA/c7GXf5cYKou4JDhoh51mIKFmy6o+ 5VKg== X-Forwarded-Encrypted: i=1; AJvYcCVc0Lali7f4Wfxuvz48fpUOBCWwM6HnqdHGwxQzI5an9JSIeOurJmeSEDxApNcPljDlC70zLaBo7E5vye0=@vger.kernel.org X-Gm-Message-State: AOJu0Yx63UgbOyaBYNR6eE07jUBQgkNd3Jtd35rjgM7CdQLWQW1Y2jxw SZIsYkN4LyEU8oyhR7XggwkZWWmSBlNHn7QVyKbkxpumdj37O3krUt17f3Ee X-Gm-Gg: ASbGnctnzJcow6j6BQbPpWyMEkuKd+VpwFt3vu1SO4MpvWO2vMGmgL6GpVNjM/KEAUU u4ZWTAo38KYu4JxEOm+7+QZJMEXnTx342qDEgDrbWVnWO02wmHq+jJ256oF5l69rD7O9Gm4gRLV /eSivfjrl6INWMBqrBDJamubuEKt//q90QD2ub+NEHtvUrg094a+bSwUNR/N2AQ7Blarv8pBfeH 5kOXUkDAPVfJom1/DahMlwB1p/zCVtT6r/FJd6RIuzRYubw9cF5ULKEcKf8YuygbrYm5ZNQsShC kksR/JgmPxzKY2h/Qlu7xBfCeXTgnj6HhF9u4hEnynPmEznScXHA280SW0xrG4igPkkgWVDnYCG XlUXYm7A= X-Google-Smtp-Source: AGHT+IE1pAuGx7BQ7H2vAjWVPS1Ixjg3wxAx2UDJGXmnGcGGEMGV5PCvJgx27ocQocD20/K72ooAGw== X-Received: by 2002:ac8:7dcf:0:b0:472:6aa:d6be with SMTP id d75a77b69052e-474bc069f2fmr185735581cf.17.1741060506261; Mon, 03 Mar 2025 19:55:06 -0800 (PST) Received: from nerdopolis2.mynetworksettings.com ([2600:4040:5e66:a800:745f:1ed4:1113:4077]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-474691a1f2csm67567041cf.13.2025.03.03.19.55.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 03 Mar 2025 19:55:05 -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 v6 3/3] tty: Change order of ttynull to be linked sooner if enabled as a console. Date: Mon, 3 Mar 2025 22:54:47 -0500 Message-ID: <20250304035447.3138221-4-adamsimonelli@gmail.com> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20250304035447.3138221-1-adamsimonelli@gmail.com> References: <20250304035447.3138221-1-adamsimonelli@gmail.com> Precedence: bulk X-Mailing-List: linux-serial@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 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 | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/tty/Makefile b/drivers/tty/Makefile index 07aca5184a55..a4caf32a2014 100644 --- a/drivers/tty/Makefile +++ b/drivers/tty/Makefile @@ -11,6 +11,11 @@ obj-$(CONFIG_N_HDLC) += n_hdlc.o obj-$(CONFIG_N_GSM) += n_gsm.o obj-y += vt/ +# If ttynull is configured to be a console by default, ensure that it is linked +# earlier before a real one is selected. +obj-$(CONFIG_NULL_TTY_DEFAULT_CONSOLE) \ + += ttynull.o + obj-$(CONFIG_HVC_DRIVER) += hvc/ obj-y += serial/ obj-$(CONFIG_SERIAL_DEV_BUS) += serdev/ @@ -20,7 +25,13 @@ obj-$(CONFIG_AMIGA_BUILTIN_SERIAL) += amiserial.o obj-$(CONFIG_MOXA_INTELLIO) += moxa.o obj-$(CONFIG_MOXA_SMARTIO) += mxser.o obj-$(CONFIG_NOZOMI) += nozomi.o + +# If ttynull is enabled, but not as a boot console, it is linked and used later +# after the real ones. +ifneq ($(CONFIG_NULL_TTY_DEFAULT_CONSOLE),y) obj-$(CONFIG_NULL_TTY) += ttynull.o +endif + obj-$(CONFIG_SYNCLINK_GT) += synclink_gt.o obj-$(CONFIG_PPC_EPAPR_HV_BYTECHAN) += ehv_bytechan.o obj-$(CONFIG_GOLDFISH_TTY) += goldfish.o