From patchwork Tue Oct 30 22:11:03 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Doug Anderson X-Patchwork-Id: 10661671 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 581811751 for ; Tue, 30 Oct 2018 22:11:44 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 46D492A89E for ; Tue, 30 Oct 2018 22:11:44 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3AE2A2AA78; Tue, 30 Oct 2018 22:11:44 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D7F102A89E for ; Tue, 30 Oct 2018 22:11:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728431AbeJaHG6 (ORCPT ); Wed, 31 Oct 2018 03:06:58 -0400 Received: from mail-pl1-f195.google.com ([209.85.214.195]:46693 "EHLO mail-pl1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728351AbeJaHG6 (ORCPT ); Wed, 31 Oct 2018 03:06:58 -0400 Received: by mail-pl1-f195.google.com with SMTP id bb7-v6so6221587plb.13 for ; Tue, 30 Oct 2018 15:11:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=456uG5PlWBnfGUDyET8jKISVXeQZt6ggTh3gygckLP0=; b=BOyMZrSf0rDdTl6nQ87KKVm4mipKJOEpXnTSeLRqAacNT8A+mGPuzJT5RlQ5KEma86 vCK7u5ZxaOWf+wT+U99ktUD7wkcogFKmkbQizZ5GSvhJOG8ld1pAAT0a1u6T1wPrdvpu TK9gy3tPlJKCKO6mY0nvyBrhY4xHwsECJABTw= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=456uG5PlWBnfGUDyET8jKISVXeQZt6ggTh3gygckLP0=; b=kKqQuLJi30hVjmkbSGey70grR9vd9WTDi+Lpz5Yu0+dVxX2kqtUC+tVLr+5+XF3UaM 4R4c4tlWLhifR+SnjzKV5DQJTgfQ2r9ewg7PUdtPP+KPi6G3MEvr/G3dj/KKfqUVYFtR wxRYhJ3XsPmMZnh3uSkztUXfiyYD1OFmhuwUbIyWoadmgn4x6p/tBzW2yLQL7jEi7fo8 1h2MKf6iUCW10kO7g5sQ+3HqbaBkJYg2M0sFvuZuVYMZzB67RV96FLCyqrUp/ObZJpE4 0aF64w2T0VX6dSHe+ZzDo+6TW6CxMvi5ozfohV7ASDma6WzJsEYPahpEFsr7F5O9MTs3 9lbw== X-Gm-Message-State: AGRZ1gIxKom9io4/KkhEfHXZzozMalr6zR0hLwEWOtgjmsmLlYwuPNHV C5+roFgpctrm1WDkApGYETTC+g== X-Google-Smtp-Source: AJdET5dNw5dl4KoW1C3gIRAymO5X3IH4UK1BUJscMzsym9F+sRJkSiHYwKcLxq0iCeAQ8NRIcQ6Sqw== X-Received: by 2002:a17:902:47:: with SMTP id 65-v6mr545840pla.112.1540937502633; Tue, 30 Oct 2018 15:11:42 -0700 (PDT) Received: from tictac2.mtv.corp.google.com ([2620:15c:202:1:c8e0:70d7:4be7:a36]) by smtp.gmail.com with ESMTPSA id b11-v6sm12844491pgi.10.2018.10.30.15.11.41 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 30 Oct 2018 15:11:41 -0700 (PDT) From: Douglas Anderson To: Greg Kroah-Hartman , Jiri Slaby Cc: linux-arm-kernel@lists.infradead.org, vigneshr@ti.com, linux-aspeed@lists.ozlabs.org, andrew@aj.id.au, tony@atomide.com, joel@jms.id.au, linux-serial@vger.kernel.org, linux-arm-msm@vger.kernel.org, andriy.shevchenko@linux.intel.com, dan.carpenter@oracle.com, jk@ozlabs.org, Douglas Anderson Subject: [PATCH v2 1/5] serial: qcom_geni_serial: Finish supporting sysrq Date: Tue, 30 Oct 2018 15:11:03 -0700 Message-Id: <20181030221107.79758-2-dianders@chromium.org> X-Mailer: git-send-email 2.19.1.568.g152ad8e336-goog In-Reply-To: <20181030221107.79758-1-dianders@chromium.org> References: <20181030221107.79758-1-dianders@chromium.org> MIME-Version: 1.0 Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The geni serial driver already had some sysrq code in it, but since SUPPORT_SYSRQ wasn't defined the code didn't do anything useful. Let's make it useful by adding that define using the same formula found in other serial drivers. In order to prevent deadlock, we'll take a page from the 'msm_serial.c' where the spinlock is released around uart_handle_sysrq_char(). This seemed better than copying from '8250_port.c' where we skip locking in the console_write function since the '8250_port.c' method can cause lockdep warnings when dropping into kgdb. Signed-off-by: Douglas Anderson --- drivers/tty/serial/qcom_geni_serial.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c index 1515074e18fb..b83e3554bced 100644 --- a/drivers/tty/serial/qcom_geni_serial.c +++ b/drivers/tty/serial/qcom_geni_serial.c @@ -1,6 +1,10 @@ // SPDX-License-Identifier: GPL-2.0 // Copyright (c) 2017-2018, The Linux foundation. All rights reserved. +#if defined(CONFIG_SERIAL_QCOM_GENI_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ) +# define SUPPORT_SYSRQ +#endif + #include #include #include @@ -495,7 +499,10 @@ static int handle_rx_console(struct uart_port *uport, u32 bytes, bool drop) continue; } + spin_unlock(&uport->lock); sysrq = uart_handle_sysrq_char(uport, buf[c]); + spin_lock(&uport->lock); + if (!sysrq) tty_insert_flip_char(tport, buf[c], TTY_NORMAL); } From patchwork Tue Oct 30 22:11:04 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Doug Anderson X-Patchwork-Id: 10661673 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 21ECE13A4 for ; Tue, 30 Oct 2018 22:11:46 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 12D782A89E for ; Tue, 30 Oct 2018 22:11:46 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 06E6C2AA78; Tue, 30 Oct 2018 22:11:46 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 85DA42A89E for ; Tue, 30 Oct 2018 22:11:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728455AbeJaHHA (ORCPT ); Wed, 31 Oct 2018 03:07:00 -0400 Received: from mail-pl1-f193.google.com ([209.85.214.193]:37284 "EHLO mail-pl1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728428AbeJaHHA (ORCPT ); Wed, 31 Oct 2018 03:07:00 -0400 Received: by mail-pl1-f193.google.com with SMTP id bh10-v6so6235709plb.4 for ; Tue, 30 Oct 2018 15:11:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=bspTmsO922c2ahVBjIPUGFrdX2Jss9sHKADxEgLE8Zg=; b=fXrkSqJb02IXYc9OaPtpE8lukq5eiftMgaB1hlPx0vqODF6bT9VcXBRt4g9hiDHRMU JKR240rzzYMjLgN14UurlmJEjHE3KhP1u+z4ogtnhyLALwSmcw6cJbRzW8/SVwdQpZS3 Osnt6c+YhFoHSKHMgD7J0HVl/zna8h2Us3tL4= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=bspTmsO922c2ahVBjIPUGFrdX2Jss9sHKADxEgLE8Zg=; b=HujvlFvHe1cTR6xe/RMN/ndBmF7rDAHa1xok34XPoy9tyYQzeytuqGVvmZX5xLu2h0 5dnKG08ERSZG/nk7Qa0UxQbQlza8BCQHraRr5SuKjIBX78FIjNkaCRxVT8QRqcCGdBP3 uvuRJ5TMEk5Xp9S719K8X4P8ggA/4MUy6fKlAZq2Udrg0ZRjiQUvpVM7y07iQbklDi+U DgoOLMSYiMyvfI2y9PvfShYx25bOTm961eLIr6718NMKBMVO5g1o4HwDlnyf0mFKDdSC a/86PlxqR9SwUXVNbNe8OrM4IrWLxxvtI9Gk0dMD0rkDpzCDQ0ShDL1zBNJSnKcfM/h6 cU0Q== X-Gm-Message-State: AGRZ1gKQaxgSG+S5iB0qNzSzbgQWKakosjLf1ZWCmnawqzT6T/vrKf05 Mm0SDtppMrVHM8S8wZz32bKwiQ== X-Google-Smtp-Source: AJdET5e0EgLWFkrFaDzyWDjr7tELzbl7ptVfBIkX9G8E0uwGHrGEl3sb848cXEq/Khpz1LFEs46ASw== X-Received: by 2002:a17:902:7c94:: with SMTP id y20-v6mr525436pll.218.1540937504215; Tue, 30 Oct 2018 15:11:44 -0700 (PDT) Received: from tictac2.mtv.corp.google.com ([2620:15c:202:1:c8e0:70d7:4be7:a36]) by smtp.gmail.com with ESMTPSA id b11-v6sm12844491pgi.10.2018.10.30.15.11.42 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 30 Oct 2018 15:11:43 -0700 (PDT) From: Douglas Anderson To: Greg Kroah-Hartman , Jiri Slaby Cc: linux-arm-kernel@lists.infradead.org, vigneshr@ti.com, linux-aspeed@lists.ozlabs.org, andrew@aj.id.au, tony@atomide.com, joel@jms.id.au, linux-serial@vger.kernel.org, linux-arm-msm@vger.kernel.org, andriy.shevchenko@linux.intel.com, dan.carpenter@oracle.com, jk@ozlabs.org, Douglas Anderson Subject: [PATCH v2 2/5] serial: core: Allow processing sysrq at port unlock time Date: Tue, 30 Oct 2018 15:11:04 -0700 Message-Id: <20181030221107.79758-3-dianders@chromium.org> X-Mailer: git-send-email 2.19.1.568.g152ad8e336-goog In-Reply-To: <20181030221107.79758-1-dianders@chromium.org> References: <20181030221107.79758-1-dianders@chromium.org> MIME-Version: 1.0 Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Right now serial drivers process sysrq keys deep in their character receiving code. This means that they've already grabbed their port->lock spinlock. This can end up getting in the way if we've go to do serial stuff (especially kgdb) in response to the sysrq. Serial drivers have various hacks in them to handle this. Looking at '8250_port.c' you can see that the console_write() skips locking if we're in the sysrq handler. Looking at 'msm_serial.c' you can see that the port lock is dropped around uart_handle_sysrq_char(). It turns out that these hacks aren't exactly perfect. If you have lockdep turned on and use something like the 8250_port hack you'll get a splat that looks like: WARNING: possible circular locking dependency detected [...] is trying to acquire lock: ... (console_owner){-.-.}, at: console_unlock+0x2e0/0x5e4 but task is already holding lock: ... (&port_lock_key){-.-.}, at: serial8250_handle_irq+0x30/0xe4 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&port_lock_key){-.-.}: _raw_spin_lock_irqsave+0x58/0x70 serial8250_console_write+0xa8/0x250 univ8250_console_write+0x40/0x4c console_unlock+0x528/0x5e4 register_console+0x2c4/0x3b0 uart_add_one_port+0x350/0x478 serial8250_register_8250_port+0x350/0x3a8 dw8250_probe+0x67c/0x754 platform_drv_probe+0x58/0xa4 really_probe+0x150/0x294 driver_probe_device+0xac/0xe8 __driver_attach+0x98/0xd0 bus_for_each_dev+0x84/0xc8 driver_attach+0x2c/0x34 bus_add_driver+0xf0/0x1ec driver_register+0xb4/0x100 __platform_driver_register+0x60/0x6c dw8250_platform_driver_init+0x20/0x28 ... -> #0 (console_owner){-.-.}: lock_acquire+0x1e8/0x214 console_unlock+0x35c/0x5e4 vprintk_emit+0x230/0x274 vprintk_default+0x7c/0x84 vprintk_func+0x190/0x1bc printk+0x80/0xa0 __handle_sysrq+0x104/0x21c handle_sysrq+0x30/0x3c serial8250_read_char+0x15c/0x18c serial8250_rx_chars+0x34/0x74 serial8250_handle_irq+0x9c/0xe4 dw8250_handle_irq+0x98/0xcc serial8250_interrupt+0x50/0xe8 ... other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&port_lock_key); lock(console_owner); lock(&port_lock_key); lock(console_owner); *** DEADLOCK *** The hack used in 'msm_serial.c' doesn't cause the above splats but it seems a bit ugly to unlock / lock our spinlock deep in our irq handler. It seems like we could defer processing the sysrq until the end of the interrupt handler right after we've unlocked the port. With this scheme if a whole batch of sysrq characters comes in one irq then we won't handle them all, but that seems like it should be a fine compromise. Signed-off-by: Douglas Anderson --- include/linux/serial_core.h | 37 ++++++++++++++++++++++++++++++++++++- 1 file changed, 36 insertions(+), 1 deletion(-) diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h index 406edae44ca3..3460b15a2607 100644 --- a/include/linux/serial_core.h +++ b/include/linux/serial_core.h @@ -173,6 +173,7 @@ struct uart_port { struct console *cons; /* struct console, if any */ #if defined(CONFIG_SERIAL_CORE_CONSOLE) || defined(SUPPORT_SYSRQ) unsigned long sysrq; /* sysrq timeout */ + unsigned int sysrq_ch; /* char for sysrq */ #endif /* flags must be updated while holding port mutex */ @@ -482,8 +483,42 @@ uart_handle_sysrq_char(struct uart_port *port, unsigned int ch) } return 0; } +static inline int +uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch) +{ + if (port->sysrq) { + if (ch && time_before(jiffies, port->sysrq)) { + port->sysrq_ch = ch; + port->sysrq = 0; + return 1; + } + port->sysrq = 0; + } + return 0; +} +static inline void +uart_unlock_and_check_sysrq(struct uart_port *port, unsigned long irqflags) +{ + int sysrq_ch; + + sysrq_ch = port->sysrq_ch; + port->sysrq_ch = 0; + + spin_unlock_irqrestore(&port->lock, irqflags); + + if (sysrq_ch) + handle_sysrq(sysrq_ch); +} #else -#define uart_handle_sysrq_char(port,ch) ({ (void)port; 0; }) +static inline int +uart_handle_sysrq_char(struct uart_port *port, unsigned int ch) { return 0; } +static inline int +uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch) { return 0; } +static inline void +uart_unlock_and_check_sysrq(struct uart_port *port, unsigned long irqflags) +{ + spin_unlock_irqrestore(&port->lock, irqflags); +} #endif /* From patchwork Tue Oct 30 22:11:05 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Doug Anderson X-Patchwork-Id: 10661675 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 0F19913A4 for ; Tue, 30 Oct 2018 22:11:48 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id F36832AA6A for ; 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Tue, 30 Oct 2018 15:11:45 -0700 (PDT) Received: from tictac2.mtv.corp.google.com ([2620:15c:202:1:c8e0:70d7:4be7:a36]) by smtp.gmail.com with ESMTPSA id b11-v6sm12844491pgi.10.2018.10.30.15.11.44 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 30 Oct 2018 15:11:44 -0700 (PDT) From: Douglas Anderson To: Greg Kroah-Hartman , Jiri Slaby Cc: linux-arm-kernel@lists.infradead.org, vigneshr@ti.com, linux-aspeed@lists.ozlabs.org, andrew@aj.id.au, tony@atomide.com, joel@jms.id.au, linux-serial@vger.kernel.org, linux-arm-msm@vger.kernel.org, andriy.shevchenko@linux.intel.com, dan.carpenter@oracle.com, jk@ozlabs.org, Douglas Anderson Subject: [PATCH v2 3/5] serial: qcom_geni_serial: Process sysrq at port unlock time Date: Tue, 30 Oct 2018 15:11:05 -0700 Message-Id: <20181030221107.79758-4-dianders@chromium.org> X-Mailer: git-send-email 2.19.1.568.g152ad8e336-goog In-Reply-To: <20181030221107.79758-1-dianders@chromium.org> References: <20181030221107.79758-1-dianders@chromium.org> MIME-Version: 1.0 Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Let's take advantage of the new ("serial: core: Allow processing sysrq at port unlock time") to handle sysrqs more cleanly. Signed-off-by: Douglas Anderson --- drivers/tty/serial/qcom_geni_serial.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c index b83e3554bced..29ddc1fc65f8 100644 --- a/drivers/tty/serial/qcom_geni_serial.c +++ b/drivers/tty/serial/qcom_geni_serial.c @@ -499,9 +499,7 @@ static int handle_rx_console(struct uart_port *uport, u32 bytes, bool drop) continue; } - spin_unlock(&uport->lock); - sysrq = uart_handle_sysrq_char(uport, buf[c]); - spin_lock(&uport->lock); + sysrq = uart_prepare_sysrq_char(uport, buf[c]); if (!sysrq) tty_insert_flip_char(tport, buf[c], TTY_NORMAL); @@ -811,7 +809,8 @@ static irqreturn_t qcom_geni_serial_isr(int isr, void *dev) qcom_geni_serial_handle_rx(uport, drop_rx); out_unlock: - spin_unlock_irqrestore(&uport->lock, flags); + uart_unlock_and_check_sysrq(uport, flags); + return IRQ_HANDLED; } From patchwork Tue Oct 30 22:11:06 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Doug Anderson X-Patchwork-Id: 10661677 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id F29631751 for ; 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Tue, 30 Oct 2018 15:11:47 -0700 (PDT) Received: from tictac2.mtv.corp.google.com ([2620:15c:202:1:c8e0:70d7:4be7:a36]) by smtp.gmail.com with ESMTPSA id b11-v6sm12844491pgi.10.2018.10.30.15.11.45 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 30 Oct 2018 15:11:46 -0700 (PDT) From: Douglas Anderson To: Greg Kroah-Hartman , Jiri Slaby Cc: linux-arm-kernel@lists.infradead.org, vigneshr@ti.com, linux-aspeed@lists.ozlabs.org, andrew@aj.id.au, tony@atomide.com, joel@jms.id.au, linux-serial@vger.kernel.org, linux-arm-msm@vger.kernel.org, andriy.shevchenko@linux.intel.com, dan.carpenter@oracle.com, jk@ozlabs.org, Douglas Anderson Subject: [PATCH v2 4/5] serial: core: Include console.h from serial_core.h Date: Tue, 30 Oct 2018 15:11:06 -0700 Message-Id: <20181030221107.79758-5-dianders@chromium.org> X-Mailer: git-send-email 2.19.1.568.g152ad8e336-goog In-Reply-To: <20181030221107.79758-1-dianders@chromium.org> References: <20181030221107.79758-1-dianders@chromium.org> MIME-Version: 1.0 Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP In the static inline function uart_handle_break() in serial_core.h we dereference port->cons. That gives an error unless console.h is also included. This error hasn't shown up till now because everyone who has defined SUPPORT_SYSRQ has also included console.h, but it's a bit ugly to make this requirement. Let's make the include explicit. Signed-off-by: Douglas Anderson --- include/linux/serial_core.h | 1 + 1 file changed, 1 insertion(+) diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h index 3460b15a2607..ff9d0ee32f11 100644 --- a/include/linux/serial_core.h +++ b/include/linux/serial_core.h @@ -22,6 +22,7 @@ #include #include +#include #include #include #include From patchwork Tue Oct 30 22:11:07 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Doug Anderson X-Patchwork-Id: 10661679 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 3DBAC1751 for ; Tue, 30 Oct 2018 22:11:51 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2C32A2A89E for ; Tue, 30 Oct 2018 22:11:51 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 204D32AA78; Tue, 30 Oct 2018 22:11:51 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7D84B2A89E for ; Tue, 30 Oct 2018 22:11:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728444AbeJaHHF (ORCPT ); Wed, 31 Oct 2018 03:07:05 -0400 Received: from mail-pf1-f193.google.com ([209.85.210.193]:41042 "EHLO mail-pf1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728467AbeJaHHF (ORCPT ); Wed, 31 Oct 2018 03:07:05 -0400 Received: by mail-pf1-f193.google.com with SMTP id e22-v6so3524022pfn.8 for ; Tue, 30 Oct 2018 15:11:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=D/srr377gx/CBcW4oZq1iML+JVouTiEFf8QM91L4b9s=; b=ZfjylPUkbrAU9ZCiHNybarzU65qDjhAFwDP3RzRjBghrI4CeZ7SIV3uBhEYAL7P89f fW5KvIe1ai7z7nfOafdMIkFgIJv4i6H4IZAxDNAmNt5YR6wLuNXvh4ekSkOt2PjjEYJw lFovj5f90vpadHtLoXpjsGzKDwZAOQjL4u3/E= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=D/srr377gx/CBcW4oZq1iML+JVouTiEFf8QM91L4b9s=; b=WFxES7TW+MdjdVtCgzC4H2LsNLB0/PGtA8S4URHR+l9Xy6iTP4GhTSfZ+2N6mvuuLP wBI2HR6K+CfoYor443c2oLYZ09BbGFCxZxESN7ypfa/iavDln9C/5p8ma5XApoVi6qGH BzoYcU4XQtfU7cSP/Qs3sZxDRF1NhhAB9BvCwDNx09ZUeZ4cXCoX/J48osE9J6rD5Tls xH6I+Rr91lKu8gfTB7tDdWWmKNrvp5b/EQUlVoMQQkaJ9pAMzfYWDpI51UlBpHui5IU1 UiVYUoh4ErCY6CxZDK/JCkTZYxMaEcsobnSlf6UDZuTXjgvw1uQnB3fZVhakdat0A+Qx HOJg== X-Gm-Message-State: AGRZ1gJpnk+TDQqsKXl6sFeVRzR/cO4ETsnBCfQRH0jA6iP+RCebIf1k Mj2zTCQOe9wJeyiDOVmyoaW9sRyHV7U= X-Google-Smtp-Source: AJdET5e8YEAm+0QPBnqsugqh9po5N6wj7KwtW7ZMCVO+9U9bzZpimy/iwrK+kU8blQuptyANu3r/+g== X-Received: by 2002:a63:9a09:: with SMTP id o9mr504845pge.94.1540937508885; Tue, 30 Oct 2018 15:11:48 -0700 (PDT) Received: from tictac2.mtv.corp.google.com ([2620:15c:202:1:c8e0:70d7:4be7:a36]) by smtp.gmail.com with ESMTPSA id b11-v6sm12844491pgi.10.2018.10.30.15.11.47 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 30 Oct 2018 15:11:48 -0700 (PDT) From: Douglas Anderson To: Greg Kroah-Hartman , Jiri Slaby Cc: linux-arm-kernel@lists.infradead.org, vigneshr@ti.com, linux-aspeed@lists.ozlabs.org, andrew@aj.id.au, tony@atomide.com, joel@jms.id.au, linux-serial@vger.kernel.org, linux-arm-msm@vger.kernel.org, andriy.shevchenko@linux.intel.com, dan.carpenter@oracle.com, jk@ozlabs.org, Douglas Anderson Subject: [PATCH v2 5/5] serial: 8250: Process sysrq at port unlock time Date: Tue, 30 Oct 2018 15:11:07 -0700 Message-Id: <20181030221107.79758-6-dianders@chromium.org> X-Mailer: git-send-email 2.19.1.568.g152ad8e336-goog In-Reply-To: <20181030221107.79758-1-dianders@chromium.org> References: <20181030221107.79758-1-dianders@chromium.org> MIME-Version: 1.0 Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Let's take advantage of the new ("serial: core: Allow processing sysrq at port unlock time") to handle sysrqs more cleanly. Signed-off-by: Douglas Anderson --- I don't have a great way to test all 8250 variants, but I've at least tested rk3288 / rk3399 and they seem to work. Hopefully I got the aspeed_vuart / fsl / omap variants right (I only compile tested those). drivers/tty/serial/8250/8250_aspeed_vuart.c | 6 +++++- drivers/tty/serial/8250/8250_fsl.c | 6 +++++- drivers/tty/serial/8250/8250_omap.c | 6 +++++- drivers/tty/serial/8250/8250_port.c | 8 +++----- 4 files changed, 18 insertions(+), 8 deletions(-) diff --git a/drivers/tty/serial/8250/8250_aspeed_vuart.c b/drivers/tty/serial/8250/8250_aspeed_vuart.c index 435bec40dee6..0438d9a905ce 100644 --- a/drivers/tty/serial/8250/8250_aspeed_vuart.c +++ b/drivers/tty/serial/8250/8250_aspeed_vuart.c @@ -5,6 +5,10 @@ * Copyright (C) 2016 Jeremy Kerr , IBM Corp. * Copyright (C) 2006 Arnd Bergmann , IBM Corp. */ +#if defined(CONFIG_SERIAL_8250_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ) +#define SUPPORT_SYSRQ +#endif + #include #include #include @@ -293,7 +297,7 @@ static int aspeed_vuart_handle_irq(struct uart_port *port) if (lsr & UART_LSR_THRE) serial8250_tx_chars(up); - spin_unlock_irqrestore(&port->lock, flags); + uart_unlock_and_check_sysrq(port, flags); return 1; } diff --git a/drivers/tty/serial/8250/8250_fsl.c b/drivers/tty/serial/8250/8250_fsl.c index 6640a4c7ddd1..ff3dcaea5d93 100644 --- a/drivers/tty/serial/8250/8250_fsl.c +++ b/drivers/tty/serial/8250/8250_fsl.c @@ -1,4 +1,8 @@ // SPDX-License-Identifier: GPL-2.0 +#if defined(CONFIG_SERIAL_8250_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ) +#define SUPPORT_SYSRQ +#endif + #include #include @@ -54,7 +58,7 @@ int fsl8250_handle_irq(struct uart_port *port) serial8250_tx_chars(up); up->lsr_saved_flags = orig_lsr; - spin_unlock_irqrestore(&up->port.lock, flags); + uart_unlock_and_check_sysrq(&up->port, flags); return 1; } EXPORT_SYMBOL_GPL(fsl8250_handle_irq); diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c index a019286f8bb6..ad7ba7d0f28d 100644 --- a/drivers/tty/serial/8250/8250_omap.c +++ b/drivers/tty/serial/8250/8250_omap.c @@ -8,6 +8,10 @@ * */ +#if defined(CONFIG_SERIAL_8250_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ) +#define SUPPORT_SYSRQ +#endif + #include #include #include @@ -1085,7 +1089,7 @@ static int omap_8250_dma_handle_irq(struct uart_port *port) } } - spin_unlock_irqrestore(&port->lock, flags); + uart_unlock_and_check_sysrq(port, flags); serial8250_rpm_put(up); return 1; } diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c index 3f779d25ec0c..d2f3310abe54 100644 --- a/drivers/tty/serial/8250/8250_port.c +++ b/drivers/tty/serial/8250/8250_port.c @@ -1736,7 +1736,7 @@ void serial8250_read_char(struct uart_8250_port *up, unsigned char lsr) else if (lsr & UART_LSR_FE) flag = TTY_FRAME; } - if (uart_handle_sysrq_char(port, ch)) + if (uart_prepare_sysrq_char(port, ch)) return; uart_insert_char(port, lsr, UART_LSR_OE, ch, flag); @@ -1878,7 +1878,7 @@ int serial8250_handle_irq(struct uart_port *port, unsigned int iir) if ((!up->dma || up->dma->tx_err) && (status & UART_LSR_THRE)) serial8250_tx_chars(up); - spin_unlock_irqrestore(&port->lock, flags); + uart_unlock_and_check_sysrq(port, flags); return 1; } EXPORT_SYMBOL_GPL(serial8250_handle_irq); @@ -3239,9 +3239,7 @@ void serial8250_console_write(struct uart_8250_port *up, const char *s, serial8250_rpm_get(up); - if (port->sysrq) - locked = 0; - else if (oops_in_progress) + if (oops_in_progress) locked = spin_trylock_irqsave(&port->lock, flags); else spin_lock_irqsave(&port->lock, flags);