linux-kernel - [PATCH 01/13] serial: bfin_sport_uart: work around anomaly 05000473 (make 32bit fifo read atomic)

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 for Android: free password hash cracker in your pocket

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

Date:	Tue,  9 Mar 2010 12:25:28 -0500
From:	Mike Frysinger <vapier@...too.org>
To:	linux-serial@...r.kernel.org, Alan Cox <alan@...rguk.ukuu.org.uk>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org,
	uclinux-dist-devel@...ckfin.uclinux.org,
	Sonic Zhang <sonic.zhang@...log.com>
Subject: [PATCH 01/13] serial: bfin_sport_uart: work around anomaly 05000473 (make 32bit fifo read atomic)

From: Sonic Zhang <sonic.zhang@...log.com>

We cannot let a 32-bit RX FIFO read be interrupted otherwise a fake RX
underflow error might be generated.

URL: http://blackfin.uclinux.org/gf/tracker/5145
Signed-off-by: Sonic Zhang <sonic.zhang@...log.com>
Signed-off-by: Mike Frysinger <vapier@...too.org>
---
 drivers/serial/bfin_sport_uart.h |   16 +++++++++++++++-
 1 files changed, 15 insertions(+), 1 deletions(-)

diff --git a/drivers/serial/bfin_sport_uart.h b/drivers/serial/bfin_sport_uart.h
index abe0361..9791fcc 100644
--- a/drivers/serial/bfin_sport_uart.h
+++ b/drivers/serial/bfin_sport_uart.h
@@ -37,7 +37,21 @@
 #define SPORT_GET_TFSDIV(sport)		bfin_read16(((sport)->port.membase + OFFSET_TFSDIV))
 #define SPORT_GET_TX(sport)		bfin_read16(((sport)->port.membase + OFFSET_TX))
 #define SPORT_GET_RX(sport)		bfin_read16(((sport)->port.membase + OFFSET_RX))
-#define SPORT_GET_RX32(sport)		bfin_read32(((sport)->port.membase + OFFSET_RX))
+/*
+ * If another interrupt fires while doing a 32-bit read from RX FIFO,
+ * a fake RX underflow error will be generated.  So disable interrupts
+ * to prevent interruption while reading the FIFO.
+ */
+#define SPORT_GET_RX32(sport) \
+({ \
+	unsigned int __ret; \
+	if (ANOMALY_05000473) \
+		local_irq_disable(); \
+	__ret = bfin_read32((sport)->port.membase + OFFSET_RX); \
+	if (ANOMALY_05000473) \
+		local_irq_enable(); \
+	__ret; \
+})
 #define SPORT_GET_RCR1(sport)		bfin_read16(((sport)->port.membase + OFFSET_RCR1))
 #define SPORT_GET_RCR2(sport)		bfin_read16(((sport)->port.membase + OFFSET_RCR2))
 #define SPORT_GET_RCLKDIV(sport)	bfin_read16(((sport)->port.membase + OFFSET_RCLKDIV))
-- 
1.7.0.2

--
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/