From: Stephen Warren <swarren@wwwdotorg.org>
To: Mark Rutland <mark.rutland@arm.com>
Cc: linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, tglx@linutronix.de,
nico@linaro.org, Will.Deacon@arm.com, Marc.Zyngier@arm.com,
john.stultz@linaro.org
Subject: Re: [PATCHv3 4/4] arm: Add generic timer broadcast support
Date: Wed, 06 Feb 2013 13:51:43 -0700 [thread overview]
Message-ID: <5112C25F.6000508@wwwdotorg.org> (raw)
In-Reply-To: <1358183124-28461-5-git-send-email-mark.rutland@arm.com>
On 01/14/2013 10:05 AM, Mark Rutland wrote:
> Implement timer_broadcast for the arm architecture, allowing for the use
> of clock_event_device_drivers decoupled from the timer tick broadcast
> mechanism.
Mark, this patch is now in next-20130206 and causes a crash during boot
on Tegra. The reason appears to be because of:
> diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
> @@ -524,7 +524,6 @@ static void __cpuinit percpu_timer_setup(void)
> struct clock_event_device *evt = &per_cpu(percpu_clockevent, cpu);
>
> evt->cpumask = cpumask_of(cpu);
> - evt->broadcast = smp_timer_broadcast;
After that change, evt->broadcast is never assigned, and hence is NULL.
Yet elsewhere in kernel/time/tick-broadcast.c it's used unconditionally:
static void tick_do_broadcast(struct cpumask *mask)
...
if (!cpumask_empty(mask)) {
...
td = &per_cpu(tick_cpu_device, cpumask_first(mask));
td->evtdev->broadcast(mask);
Now perhaps the Tegra timer driver simply isn't being set up correctly,
so the bug is there... But the only other place I can find where
->broadcast is assigned is in tick_device_uses_broadcast() which only
does it for "non-functional" timers, which doesn't apply to Tegra's timer.
WARNING: multiple messages have this Message-ID (diff)
From: swarren@wwwdotorg.org (Stephen Warren)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCHv3 4/4] arm: Add generic timer broadcast support
Date: Wed, 06 Feb 2013 13:51:43 -0700 [thread overview]
Message-ID: <5112C25F.6000508@wwwdotorg.org> (raw)
In-Reply-To: <1358183124-28461-5-git-send-email-mark.rutland@arm.com>
On 01/14/2013 10:05 AM, Mark Rutland wrote:
> Implement timer_broadcast for the arm architecture, allowing for the use
> of clock_event_device_drivers decoupled from the timer tick broadcast
> mechanism.
Mark, this patch is now in next-20130206 and causes a crash during boot
on Tegra. The reason appears to be because of:
> diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
> @@ -524,7 +524,6 @@ static void __cpuinit percpu_timer_setup(void)
> struct clock_event_device *evt = &per_cpu(percpu_clockevent, cpu);
>
> evt->cpumask = cpumask_of(cpu);
> - evt->broadcast = smp_timer_broadcast;
After that change, evt->broadcast is never assigned, and hence is NULL.
Yet elsewhere in kernel/time/tick-broadcast.c it's used unconditionally:
static void tick_do_broadcast(struct cpumask *mask)
...
if (!cpumask_empty(mask)) {
...
td = &per_cpu(tick_cpu_device, cpumask_first(mask));
td->evtdev->broadcast(mask);
Now perhaps the Tegra timer driver simply isn't being set up correctly,
so the bug is there... But the only other place I can find where
->broadcast is assigned is in tick_device_uses_broadcast() which only
does it for "non-functional" timers, which doesn't apply to Tegra's timer.
next prev parent reply other threads:[~2013-02-06 20:51 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-14 17:05 [PATCHv3 0/4] clockevents: decouple broadcast mechanism from drivers Mark Rutland
2013-01-14 17:05 ` Mark Rutland
2013-01-14 17:05 ` [PATCHv3 1/4] clockevents: Add generic timer broadcast receiver Mark Rutland
2013-01-14 17:05 ` Mark Rutland
2013-02-04 10:30 ` [tip:timers/core] " tip-bot for Mark Rutland
2013-01-14 17:05 ` [PATCHv3 2/4] clockevents: Add generic timer broadcast function Mark Rutland
2013-01-14 17:05 ` Mark Rutland
2013-02-04 10:31 ` [tip:timers/core] " tip-bot for Mark Rutland
2013-01-14 17:05 ` [PATCHv3 3/4] arm: Use generic timer broadcast receiver Mark Rutland
2013-01-14 17:05 ` Mark Rutland
2013-01-14 17:05 ` [PATCHv3 4/4] arm: Add generic timer broadcast support Mark Rutland
2013-01-14 17:05 ` Mark Rutland
2013-02-06 20:51 ` Stephen Warren [this message]
2013-02-06 20:51 ` Stephen Warren
2013-02-07 10:04 ` Mark Rutland
2013-02-07 10:04 ` Mark Rutland
2013-02-07 11:40 ` Santosh Shilimkar
2013-02-07 11:40 ` Santosh Shilimkar
2013-02-07 16:51 ` Stephen Warren
2013-02-07 16:51 ` Stephen Warren
2013-02-08 6:48 ` Santosh Shilimkar
2013-02-08 6:48 ` Santosh Shilimkar
2013-02-07 17:17 ` Mark Rutland
2013-02-07 17:17 ` Mark Rutland
2013-02-08 6:52 ` Santosh Shilimkar
2013-02-08 6:52 ` Santosh Shilimkar
2013-02-07 16:49 ` Stephen Warren
2013-02-07 16:49 ` Stephen Warren
2013-02-07 17:25 ` Mark Rutland
2013-02-07 17:25 ` Mark Rutland
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