1 files changed, 17 insertions, 21 deletions

diff --git a/arch/s390/include/asm/mmu_context.h b/arch/s390/include/asm/mmu_context.h
index cf4c1cb17dcd..65154eaa3714 100644
--- a/arch/s390/include/asm/mmu_context.h
+++ b/arch/s390/include/asm/mmu_context.h
@@ -28,7 +28,7 @@ static inline int init_new_context(struct task_struct *tsk,
 #ifdef CONFIG_PGSTE
 	mm->context.alloc_pgste = page_table_allocate_pgste ||
 		test_thread_flag(TIF_PGSTE) ||
-		current->mm->context.alloc_pgste;
+		(current->mm && current->mm->context.alloc_pgste);
 	mm->context.has_pgste = 0;
 	mm->context.use_skey = 0;
 	mm->context.use_cmma = 0;
@@ -73,41 +73,38 @@ static inline int init_new_context(struct task_struct *tsk,
 static inline void set_user_asce(struct mm_struct *mm)
 {
 	S390_lowcore.user_asce = mm->context.asce;
-	if (current->thread.mm_segment.ar4)
-		__ctl_load(S390_lowcore.user_asce, 7, 7);
-	set_cpu_flag(CIF_ASCE_PRIMARY);
+	__ctl_load(S390_lowcore.user_asce, 1, 1);
+	clear_cpu_flag(CIF_ASCE_PRIMARY);
 }
 
 static inline void clear_user_asce(void)
 {
 	S390_lowcore.user_asce = S390_lowcore.kernel_asce;
-
-	__ctl_load(S390_lowcore.user_asce, 1, 1);
-	__ctl_load(S390_lowcore.user_asce, 7, 7);
-}
-
-static inline void load_kernel_asce(void)
-{
-	unsigned long asce;
-
-	__ctl_store(asce, 1, 1);
-	if (asce != S390_lowcore.kernel_asce)
-		__ctl_load(S390_lowcore.kernel_asce, 1, 1);
+	__ctl_load(S390_lowcore.kernel_asce, 1, 1);
 	set_cpu_flag(CIF_ASCE_PRIMARY);
 }
 
+mm_segment_t enable_sacf_uaccess(void);
+void disable_sacf_uaccess(mm_segment_t old_fs);
+
 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
 			     struct task_struct *tsk)
 {
 	int cpu = smp_processor_id();
 
-	S390_lowcore.user_asce = next->context.asce;
 	if (prev == next)
 		return;
+	S390_lowcore.user_asce = next->context.asce;
 	cpumask_set_cpu(cpu, &next->context.cpu_attach_mask);
-	/* Clear old ASCE by loading the kernel ASCE. */
-	__ctl_load(S390_lowcore.kernel_asce, 1, 1);
-	__ctl_load(S390_lowcore.kernel_asce, 7, 7);
+	/* Clear previous user-ASCE from CR1 and CR7 */
+	if (!test_cpu_flag(CIF_ASCE_PRIMARY)) {
+		__ctl_load(S390_lowcore.kernel_asce, 1, 1);
+		set_cpu_flag(CIF_ASCE_PRIMARY);
+	}
+	if (test_cpu_flag(CIF_ASCE_SECONDARY)) {
+		__ctl_load(S390_lowcore.vdso_asce, 7, 7);
+		clear_cpu_flag(CIF_ASCE_SECONDARY);
+	}
 	cpumask_clear_cpu(cpu, &prev->context.cpu_attach_mask);
 }
 
@@ -117,7 +114,6 @@ static inline void finish_arch_post_lock_switch(void)
 	struct task_struct *tsk = current;
 	struct mm_struct *mm = tsk->mm;
 
-	load_kernel_asce();
 	if (mm) {
 		preempt_disable();
 		while (atomic_read(&mm->context.flush_count))