From patchwork Sat Jan 11 02:21:45 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Josh Triplett X-Patchwork-Id: 11328675 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 9AF61138D for ; Sat, 11 Jan 2020 02:21:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 78E332082E for ; Sat, 11 Jan 2020 02:21:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728063AbgAKCVx (ORCPT ); Fri, 10 Jan 2020 21:21:53 -0500 Received: from relay1-d.mail.gandi.net ([217.70.183.193]:45951 "EHLO relay1-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728047AbgAKCVx (ORCPT ); Fri, 10 Jan 2020 21:21:53 -0500 X-Originating-IP: 50.39.173.182 Received: from localhost (50-39-173-182.bvtn.or.frontiernet.net [50.39.173.182]) (Authenticated sender: josh@joshtriplett.org) by relay1-d.mail.gandi.net (Postfix) with ESMTPSA id 19A1B240005; Sat, 11 Jan 2020 02:21:47 +0000 (UTC) Date: Fri, 10 Jan 2020 18:21:45 -0800 From: Josh Triplett To: "Rafael J. Wysocki" , Len Brown , Jonathan Corbet , Arjan van de Ven Cc: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org Subject: [PATCH] acpi: button: Provide option for power button to directly signal init Message-ID: <20200111022145.GA166025@localhost> MIME-Version: 1.0 Content-Disposition: inline Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org Virtual machines and containers often use an ACPI power button event to tell the machine to shut down gracefully. Provide an optional, extremely lightweight way to handle this event by signaling init directly, rather than running a separate daemon (such as acpid or systemd-logind) that adds to startup time and VM image complexity. By default, the power button will continue to notify userspace through the input layer. With the button.power_signal parameter set, the power button will instead send the configured signal to init. (For instance, sending SIGINT will make the power button simulate ctrl-alt-del.) Signed-off-by: Josh Triplett --- Documentation/admin-guide/kernel-parameters.txt | 6 ++++++ drivers/acpi/button.c | 11 +++++++++++ 2 files changed, 17 insertions(+) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index ade4e6ec23e0..bbb598e148f4 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -450,6 +450,12 @@ firmware feature for flushing multiple hpte entries at a time. + button.power_signal= + [ACPI] When the power button is pressed, send this + signal number to the init process. If set to 0 + (default), do not send a signal. + Format: integer + c101= [NET] Moxa C101 synchronous serial card cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection. diff --git a/drivers/acpi/button.c b/drivers/acpi/button.c index b758b45737f5..923259f132d6 100644 --- a/drivers/acpi/button.c +++ b/drivers/acpi/button.c @@ -14,6 +14,7 @@ #include #include #include +#include #include #include #include @@ -167,6 +168,10 @@ static unsigned long lid_report_interval __read_mostly = 500; module_param(lid_report_interval, ulong, 0644); MODULE_PARM_DESC(lid_report_interval, "Interval (ms) between lid key events"); +static int power_signal __read_mostly = 0; +module_param(power_signal, int, 0644); +MODULE_PARM_DESC(power_signal, "Power button sends this signal to init"); + /* -------------------------------------------------------------------------- FS Interface (/proc) -------------------------------------------------------------------------- */ @@ -426,6 +431,12 @@ static void acpi_button_notify(struct acpi_device *device, u32 event) if (button->suspended) break; + if (power_signal + && button->type == ACPI_BUTTON_TYPE_POWER) { + kill_cad_pid(power_signal, 1); + break; + } + keycode = test_bit(KEY_SLEEP, input->keybit) ? KEY_SLEEP : KEY_POWER; input_report_key(input, keycode, 1);