linux-kernel - [PATCH v10 16/19] serial: asc: Add support for KGDB's FIQ/NMI mode

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1408466769-20004-17-git-send-email-daniel.thompson@linaro.org>
Date:	Tue, 19 Aug 2014 17:46:06 +0100
From:	Daniel Thompson <daniel.thompson@...aro.org>
To:	Russell King <linux@....linux.org.uk>
Cc:	Daniel Thompson <daniel.thompson@...aro.org>,
	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	kgdb-bugreport@...ts.sourceforge.net, patches@...aro.org,
	linaro-kernel@...ts.linaro.org,
	John Stultz <john.stultz@...aro.org>,
	Anton Vorontsov <anton.vorontsov@...aro.org>,
	Colin Cross <ccross@...roid.com>, kernel-team@...roid.com,
	Rob Herring <robherring2@...il.com>,
	Linus Walleij <linus.walleij@...aro.org>,
	Ben Dooks <ben.dooks@...ethink.co.uk>,
	Catalin Marinas <catalin.marinas@....com>,
	Dave Martin <Dave.Martin@....com>,
	Fabio Estevam <festevam@...il.com>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Nicolas Pitre <nico@...aro.org>,
	Srinivas Kandagatla <srinivas.kandagatla@...il.com>,
	Maxime Coquelin <maxime.coquelin@...com>,
	Patrice Chotard <patrice.chotard@...com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Jiri Slaby <jslaby@...e.cz>, kernel@...inux.com,
	linux-serial@...r.kernel.org
Subject: [PATCH v10 16/19] serial: asc: Add support for KGDB's FIQ/NMI mode

Add a .poll_init() function that enables UART RX and registers the
UART's irq with KGDB. By providing this information to KGDB the serial
driver offers "permission" for KGDB to route the UART interrupt signal
from the drivers own handler to KGDBs FIQ handler (which will eventually
use the UART's polled I/O callbacks to interact with the user).

Note that the RX is not only enabled but also unmasked. This is required
because otherwise the FIQ handler could never trigger. This unmask is
copied from similar code in amba-pl011.c .

Signed-off-by: Daniel Thompson <daniel.thompson@...aro.org>
Cc: Srinivas Kandagatla <srinivas.kandagatla@...il.com>
Cc: Maxime Coquelin <maxime.coquelin@...com>
Cc: Patrice Chotard <patrice.chotard@...com>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: Jiri Slaby <jslaby@...e.cz>
Cc: kernel@...inux.com
Cc: linux-serial@...r.kernel.org
---
 drivers/tty/serial/st-asc.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/drivers/tty/serial/st-asc.c b/drivers/tty/serial/st-asc.c
index 8b2d735..2b5eb6e 100644
--- a/drivers/tty/serial/st-asc.c
+++ b/drivers/tty/serial/st-asc.c
@@ -30,6 +30,7 @@
 #include <linux/of_platform.h>
 #include <linux/serial_core.h>
 #include <linux/clk.h>
+#include <linux/kgdb.h>
 
 #define DRIVER_NAME "st-asc"
 #define ASC_SERIAL_NAME "ttyAS"
@@ -607,6 +608,25 @@ asc_verify_port(struct uart_port *port, struct serial_struct *ser)
 }
 
 #ifdef CONFIG_CONSOLE_POLL
+
+#ifdef CONFIG_KGDB_FIQ
+/*
+ * Prepare the UART to be used from kgdb's NMI support.
+ */
+static int asc_poll_init(struct uart_port *port)
+{
+	struct asc_port *ascport = container_of(port, struct asc_port, port);
+
+	/* register the FIQ with kgdb */
+	kgdb_register_fiq(ascport->port.irq);
+
+	/* enable RX interrupts in case the interrupt is used for NMI entry. */
+	asc_enable_rx_interrupts(port);
+
+	return 0;
+}
+#endif /* CONFIG_KGDB_FIQ */
+
 /*
  * Console polling routines for writing and reading from the uart while
  * in an interrupt or debug context (i.e. kgdb).
@@ -649,6 +669,9 @@ static struct uart_ops asc_uart_ops = {
 	.verify_port	= asc_verify_port,
 	.pm		= asc_pm,
 #ifdef CONFIG_CONSOLE_POLL
+#ifdef CONFIG_KGDB_FIQ
+	.poll_init     = asc_poll_init,
+#endif /* CONFIG_KGDB_FIQ */
 	.poll_get_char = asc_get_poll_char,
 	.poll_put_char = asc_put_poll_char,
 #endif /* CONFIG_CONSOLE_POLL */
-- 
1.9.3

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/