Merge branch 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc

* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (103 commits)
  powerpc: Fix bug in move of altivec code to vector.S
  powerpc: Add support for swiotlb on 32-bit
  powerpc/spufs: Remove unused error path
  powerpc: Fix warning when printing a resource_size_t
  powerpc/xmon: Remove unused variable in xmon.c
  powerpc/pseries: Fix warnings when printing resource_size_t
  powerpc: Shield code specific to 64-bit server processors
  powerpc: Separate PACA fields for server CPUs
  powerpc: Split exception handling out of head_64.S
  powerpc: Introduce CONFIG_PPC_BOOK3S
  powerpc: Move VMX and VSX asm code to vector.S
  powerpc: Set init_bootmem_done on NUMA platforms as well
  powerpc/mm: Fix a AB->BA deadlock scenario with nohash MMU context lock
  powerpc/mm: Fix some SMP issues with MMU context handling
  powerpc: Add PTRACE_SINGLEBLOCK support
  fbdev: Add PLB support and cleanup DCR in xilinxfb driver.
  powerpc/virtex: Add ml510 reference design device tree
  powerpc/virtex: Add Xilinx ML510 reference design support
  powerpc/virtex: refactor intc driver and add support for i8259 cascading
  powerpc/virtex: Add support for Xilinx PCI host bridge
  ...

1 files changed, 12 insertions, 7 deletions

diff --git a/arch/powerpc/mm/mmu_context_nohash.c b/arch/powerpc/mm/mmu_context_nohash.c
index 030d0005b4d..8343986809c 100644
--- a/arch/powerpc/mm/mmu_context_nohash.c
+++ b/arch/powerpc/mm/mmu_context_nohash.c
@@ -46,7 +46,7 @@ static unsigned int next_context, nr_free_contexts;
 static unsigned long *context_map;
 static unsigned long *stale_map[NR_CPUS];
 static struct mm_struct **context_mm;
-static spinlock_t context_lock = SPIN_LOCK_UNLOCKED;
+static DEFINE_SPINLOCK(context_lock);
 
 #define CTX_MAP_SIZE	\
 	(sizeof(unsigned long) * (last_context / BITS_PER_LONG + 1))
@@ -73,7 +73,6 @@ static unsigned int steal_context_smp(unsigned int id)
 	struct mm_struct *mm;
 	unsigned int cpu, max;
 
- again:
 	max = last_context - first_context;
 
 	/* Attempt to free next_context first and then loop until we manage */
@@ -108,7 +107,9 @@ static unsigned int steal_context_smp(unsigned int id)
 	spin_unlock(&context_lock);
 	cpu_relax();
 	spin_lock(&context_lock);
-	goto again;
+
+	/* This will cause the caller to try again */
+	return MMU_NO_CONTEXT;
 }
 #endif  /* CONFIG_SMP */
 
@@ -194,6 +195,8 @@ void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next)
 		WARN_ON(prev->context.active < 1);
 		prev->context.active--;
 	}
+
+ again:
 #endif /* CONFIG_SMP */
 
 	/* If we already have a valid assigned context, skip all that */
@@ -212,7 +215,8 @@ void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next)
 #ifdef CONFIG_SMP
 		if (num_online_cpus() > 1) {
 			id = steal_context_smp(id);
-			goto stolen;
+			if (id == MMU_NO_CONTEXT)
+				goto again;
 		}
 #endif /* CONFIG_SMP */
 		id = steal_context_up(id);
@@ -272,6 +276,7 @@ int init_new_context(struct task_struct *t, struct mm_struct *mm)
  */
 void destroy_context(struct mm_struct *mm)
 {
+	unsigned long flags;
 	unsigned int id;
 
 	if (mm->context.id == MMU_NO_CONTEXT)
@@ -279,18 +284,18 @@ void destroy_context(struct mm_struct *mm)
 
 	WARN_ON(mm->context.active != 0);
 
-	spin_lock(&context_lock);
+	spin_lock_irqsave(&context_lock, flags);
 	id = mm->context.id;
 	if (id != MMU_NO_CONTEXT) {
 		__clear_bit(id, context_map);
 		mm->context.id = MMU_NO_CONTEXT;
 #ifdef DEBUG_MAP_CONSISTENCY
 		mm->context.active = 0;
-		context_mm[id] = NULL;
 #endif
+		context_mm[id] = NULL;
 		nr_free_contexts++;
 	}
-	spin_unlock(&context_lock);
+	spin_unlock_irqrestore(&context_lock, flags);
 }
 
 #ifdef CONFIG_SMP