From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: <linuxppc-dev@ozlabs.org>
Subject: [PATCH 3/3] powerpc/pasemi: Use raw spinlock in SMP TB sync
Date: Wed, 17 Jun 2009 12:42:51 +1000 [thread overview]
Message-ID: <20090617024328.EAA7DDDDA1@ozlabs.org> (raw)
spin_lock() can hang if called while the timebase is frozen,
so use a raw lock instead, also disable interrupts while
at it.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---
arch/powerpc/platforms/pasemi/setup.c | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)
--- linux-work.orig/arch/powerpc/platforms/pasemi/setup.c 2009-06-17 12:13:33.000000000 +1000
+++ linux-work/arch/powerpc/platforms/pasemi/setup.c 2009-06-17 12:15:01.000000000 +1000
@@ -71,20 +71,25 @@ static void pas_restart(char *cmd)
}
#ifdef CONFIG_SMP
-static DEFINE_SPINLOCK(timebase_lock);
+static raw_spinlock_t timebase_lock;
static unsigned long timebase;
static void __devinit pas_give_timebase(void)
{
- spin_lock(&timebase_lock);
+ unsigned long flags;
+
+ local_irq_save(flags);
+ hard_irq_disable();
+ __raw_spin_lock(&timebase_lock);
mtspr(SPRN_TBCTL, TBCTL_FREEZE);
isync();
timebase = get_tb();
- spin_unlock(&timebase_lock);
+ __raw_spin_unlock(&timebase_lock);
while (timebase)
barrier();
mtspr(SPRN_TBCTL, TBCTL_RESTART);
+ local_irq_restore(flags);
}
static void __devinit pas_take_timebase(void)
@@ -92,10 +97,10 @@ static void __devinit pas_take_timebase(
while (!timebase)
smp_rmb();
- spin_lock(&timebase_lock);
+ __raw_spin_lock(&timebase_lock);
set_tb(timebase >> 32, timebase & 0xffffffff);
timebase = 0;
- spin_unlock(&timebase_lock);
+ __raw_spin_unlock(&timebase_lock);
}
struct smp_ops_t pas_smp_ops = {
reply other threads:[~2009-06-17 2:43 UTC|newest]
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