Patchwork [3/3] powerpc/pasemi: Use raw spinlock in SMP TB sync

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Submitter Benjamin Herrenschmidt
Date June 17, 2009, 2:42 a.m.
Message ID <20090617024328.EAA7DDDDA1@ozlabs.org>
Download mbox | patch
Permalink /patch/28757/
State Accepted, archived
Commit 6893ce6c1cdcf489b7ca8e6b6596208aa971a083
Delegated to: Benjamin Herrenschmidt
Headers show

Comments

Benjamin Herrenschmidt - June 17, 2009, 2:42 a.m.
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(-)

Patch

--- 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 = {