linux-kernel - [PATCH V3 2/4] ARM: smp_twd: mpcore_wdt: Fix watchdog counter loading

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]

Date:	Thu,  7 Jul 2011 16:23:14 +0400
From:	Vitaly Kuzmichev <vkuzmichev@...sta.com>
To:	linux-arm-kernel@...ts.infradead.org,
	linux-watchdog@...r.kernel.org,
	Russell King <linux@....linux.org.uk>,
	Arnd Bergmann <arnd@...db.de>,
	Wim Van Sebroeck <wim@...ana.be>,
	Marc Zyngier <marc.zyngier@....com>,
	Colin Cross <ccross@...roid.com>
Cc:	linux-kernel@...r.kernel.org,
	Vitaly Kuzmichev <vkuzmichev@...sta.com>,
	Valentine Barshak <vbarshak@...sta.com>
Subject: [PATCH V3 2/4] ARM: smp_twd: mpcore_wdt: Fix watchdog counter loading

Although the commit "98af057092f8f0dabe63c5df08adc2bbfbddb1d2
 ARM: 6126/1: ARM mpcore_wdt: fix build failure and other fixes"
resolved long standing mpcore_wdt driver build problems, it
introduced an error in the relationship between the MPcore watchdog
timer clock rate and mpcore_margin, "MPcore timer margin in seconds",
such that watchdog timeouts are now arbitrary rather than the number
of seconds specified by mpcore_margin.

This change restores mpcore_wdt_keepalive() to its equivalent
implementation prior to commit 98af057 such that watchdog timeouts now
occur as specified by mpcore_margin.

The variable 'mpcore_timer_rate' which caused that build failure was
replaced by 'twd_timer_rate'. Adding exported function to obtain
'twd_timer_rate' value in mpcore_wdt driver.

MPCORE_WATCHDOG needed to build 'mpcore_wdt' already depends on
HAVE_ARM_TWD needed to build 'smp_twd', so from the point of view of
'mpcore_wdt' driver the exported function will always exist.

Signed-off-by: Valentine Barshak <vbarshak@...sta.com>
Signed-off-by: Vitaly Kuzmichev <vkuzmichev@...sta.com>
---
 arch/arm/include/asm/smp_twd.h |    1 +
 arch/arm/kernel/smp_twd.c      |    7 +++++++
 drivers/watchdog/mpcore_wdt.c  |    4 +---
 3 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/arch/arm/include/asm/smp_twd.h b/arch/arm/include/asm/smp_twd.h
index fed9981..38130b1 100644
--- a/arch/arm/include/asm/smp_twd.h
+++ b/arch/arm/include/asm/smp_twd.h
@@ -24,5 +24,6 @@ extern void __iomem *twd_base;
 
 int twd_timer_ack(void);
 void twd_timer_setup(struct clock_event_device *);
+unsigned long twd_timer_get_rate(void);
 
 #endif
diff --git a/arch/arm/kernel/smp_twd.c b/arch/arm/kernel/smp_twd.c
index 2c277d4..c341ebc 100644
--- a/arch/arm/kernel/smp_twd.c
+++ b/arch/arm/kernel/smp_twd.c
@@ -142,3 +142,10 @@ void __cpuinit twd_timer_setup(struct clock_event_device *clk)
 
 	clockevents_register_device(clk);
 }
+
+/* Needed by mpcore_wdt */
+unsigned long twd_timer_get_rate(void)
+{
+	return twd_timer_rate;
+}
+EXPORT_SYMBOL(twd_timer_get_rate);
diff --git a/drivers/watchdog/mpcore_wdt.c b/drivers/watchdog/mpcore_wdt.c
index 2b4af22..efde50b 100644
--- a/drivers/watchdog/mpcore_wdt.c
+++ b/drivers/watchdog/mpcore_wdt.c
@@ -99,9 +99,7 @@ static void mpcore_wdt_keepalive(struct mpcore_wdt *wdt)
 
 	spin_lock(&wdt_lock);
 	/* Assume prescale is set to 256 */
-	count =  __raw_readl(wdt->base + TWD_WDOG_COUNTER);
-	count = (0xFFFFFFFFU - count) * (HZ / 5);
-	count = (count / 256) * mpcore_margin;
+	count = (twd_timer_get_rate() / 256) * mpcore_margin;
 
 	/* Reload the counter */
 	writel(count + wdt->perturb, wdt->base + TWD_WDOG_LOAD);
-- 
1.7.3.4

--
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/