1 files changed, 11 insertions, 5 deletions

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 4846bf543a8c..4ec605521504 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -241,8 +241,12 @@ void discard_lazy_cpu_state(void)
 }
 #endif /* CONFIG_SMP */
 
+static DEFINE_PER_CPU(unsigned long, current_dabr);
+
 int set_dabr(unsigned long dabr)
 {
+        __get_cpu_var(current_dabr) = dabr;
+
 #ifdef CONFIG_PPC_MERGE         /* XXX for now */
         if (ppc_md.set_dabr)
                 return ppc_md.set_dabr(dabr);
@@ -259,8 +263,6 @@ int set_dabr(unsigned long dabr)
 DEFINE_PER_CPU(struct cpu_usage, cpu_usage_array);
 #endif
 
-static DEFINE_PER_CPU(unsigned long, current_dabr);
-
 struct task_struct *__switch_to(struct task_struct *prev,
         struct task_struct *new)
 {
@@ -325,10 +327,8 @@ struct task_struct *__switch_to(struct task_struct *prev,
 
 #endif /* CONFIG_SMP */
 
-        if (unlikely(__get_cpu_var(current_dabr) != new->thread.dabr)) {
+        if (unlikely(__get_cpu_var(current_dabr) != new->thread.dabr))
                 set_dabr(new->thread.dabr);
-                __get_cpu_var(current_dabr) = new->thread.dabr;
-        }
 
         new_thread = &new->thread;
         old_thread = &current->thread;
@@ -353,6 +353,12 @@ struct task_struct *__switch_to(struct task_struct *prev,
         account_process_vtime(current);
         calculate_steal_time();
 
+        /*
+         * We can't take a PMU exception inside _switch() since there is a
+         * window where the kernel stack SLB and the kernel stack are out
+         * of sync. Hard disable here.
+         */
+        hard_irq_disable();
         last = _switch(old_thread, new_thread);
 
         local_irq_restore(flags);