--- zzzz-none-000/linux-3.10.107/arch/s390/include/asm/mmu_context.h	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/arch/s390/include/asm/mmu_context.h	2021-02-04 17:41:59.000000000 +0000
@@ -15,70 +15,110 @@
 static inline int init_new_context(struct task_struct *tsk,
 				   struct mm_struct *mm)
 {
+	spin_lock_init(&mm->context.list_lock);
+	INIT_LIST_HEAD(&mm->context.pgtable_list);
+	INIT_LIST_HEAD(&mm->context.gmap_list);
+	cpumask_clear(&mm->context.cpu_attach_mask);
 	atomic_set(&mm->context.attach_count, 0);
 	mm->context.flush_mm = 0;
-	mm->context.asce_bits = _ASCE_TABLE_LENGTH | _ASCE_USER_BITS;
-#ifdef CONFIG_64BIT
-	mm->context.asce_bits |= _ASCE_TYPE_REGION3;
+#ifdef CONFIG_PGSTE
+	mm->context.alloc_pgste = page_table_allocate_pgste;
+	mm->context.has_pgste = 0;
+	mm->context.use_skey = 0;
 #endif
-	if (current->mm && current->mm->context.alloc_pgste) {
+	switch (mm->context.asce_limit) {
+	case 1UL << 42:
 		/*
-		 * alloc_pgste indicates, that any NEW context will be created
-		 * with extended page tables. The old context is unchanged. The
-		 * page table allocation and the page table operations will
-		 * look at has_pgste to distinguish normal and extended page
-		 * tables. The only way to create extended page tables is to
-		 * set alloc_pgste and then create a new context (e.g. dup_mm).
-		 * The page table allocation is called after init_new_context
-		 * and if has_pgste is set, it will create extended page
-		 * tables.
+		 * forked 3-level task, fall through to set new asce with new
+		 * mm->pgd
 		 */
-		mm->context.has_pgste = 1;
-		mm->context.alloc_pgste = 1;
-	} else {
-		mm->context.has_pgste = 0;
-		mm->context.alloc_pgste = 0;
+	case 0:
+		/* context created by exec, set asce limit to 4TB */
+		mm->context.asce_limit = STACK_TOP_MAX;
+		mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
+				   _ASCE_USER_BITS | _ASCE_TYPE_REGION3;
+		break;
+	case 1UL << 53:
+		/* forked 4-level task, set new asce with new mm->pgd */
+		mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
+				   _ASCE_USER_BITS | _ASCE_TYPE_REGION2;
+		break;
+	case 1UL << 31:
+		/* forked 2-level compat task, set new asce with new mm->pgd */
+		mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
+				   _ASCE_USER_BITS | _ASCE_TYPE_SEGMENT;
+		/* pgd_alloc() did not increase mm->nr_pmds */
+		mm_inc_nr_pmds(mm);
 	}
-	mm->context.asce_limit = STACK_TOP_MAX;
 	crst_table_init((unsigned long *) mm->pgd, pgd_entry_type(mm));
 	return 0;
 }
 
 #define destroy_context(mm)             do { } while (0)
 
-#ifndef CONFIG_64BIT
-#define LCTL_OPCODE "lctl"
-#else
-#define LCTL_OPCODE "lctlg"
-#endif
+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);
+}
 
-static inline void update_mm(struct mm_struct *mm, struct task_struct *tsk)
+static inline void clear_user_asce(void)
 {
-	pgd_t *pgd = mm->pgd;
+	S390_lowcore.user_asce = S390_lowcore.kernel_asce;
 
-	S390_lowcore.user_asce = mm->context.asce_bits | __pa(pgd);
-	if (s390_user_mode != HOME_SPACE_MODE) {
-		/* Load primary space page table origin. */
-		asm volatile(LCTL_OPCODE" 1,1,%0\n"
-			     : : "m" (S390_lowcore.user_asce) );
-	} else
-		/* Load home space page table origin. */
-		asm volatile(LCTL_OPCODE" 13,13,%0"
-			     : : "m" (S390_lowcore.user_asce) );
-	set_fs(current->thread.mm_segment);
+	__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);
+	set_cpu_flag(CIF_ASCE);
 }
 
 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
 			     struct task_struct *tsk)
 {
-	cpumask_set_cpu(smp_processor_id(), mm_cpumask(next));
-	update_mm(next, tsk);
-	atomic_dec(&prev->context.attach_count);
-	WARN_ON(atomic_read(&prev->context.attach_count) < 0);
+	int cpu = smp_processor_id();
+
+	S390_lowcore.user_asce = next->context.asce;
+	if (prev == next)
+		return;
+	if (MACHINE_HAS_TLB_LC)
+		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);
 	atomic_inc(&next->context.attach_count);
-	/* Check for TLBs not flushed yet */
-	if (next->context.flush_mm)
-		__tlb_flush_mm(next);
+	atomic_dec(&prev->context.attach_count);
+	if (MACHINE_HAS_TLB_LC)
+		cpumask_clear_cpu(cpu, &prev->context.cpu_attach_mask);
+}
+
+#define finish_arch_post_lock_switch finish_arch_post_lock_switch
+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.attach_count) >> 16)
+			cpu_relax();
+
+		cpumask_set_cpu(smp_processor_id(), mm_cpumask(mm));
+		if (mm->context.flush_mm)
+			__tlb_flush_mm(mm);
+		preempt_enable();
+	}
+	set_fs(current->thread.mm_segment);
 }
 
 #define enter_lazy_tlb(mm,tsk)	do { } while (0)
@@ -87,20 +127,29 @@
 static inline void activate_mm(struct mm_struct *prev,
                                struct mm_struct *next)
 {
-        switch_mm(prev, next, current);
+	switch_mm(prev, next, current);
+	cpumask_set_cpu(smp_processor_id(), mm_cpumask(next));
+	set_user_asce(next);
 }
 
 static inline void arch_dup_mmap(struct mm_struct *oldmm,
 				 struct mm_struct *mm)
 {
-#ifdef CONFIG_64BIT
-	if (oldmm->context.asce_limit < mm->context.asce_limit)
-		crst_table_downgrade(mm, oldmm->context.asce_limit);
-#endif
 }
 
 static inline void arch_exit_mmap(struct mm_struct *mm)
 {
 }
 
+static inline void arch_unmap(struct mm_struct *mm,
+			struct vm_area_struct *vma,
+			unsigned long start, unsigned long end)
+{
+}
+
+static inline void arch_bprm_mm_init(struct mm_struct *mm,
+				     struct vm_area_struct *vma)
+{
+}
+
 #endif /* __S390_MMU_CONTEXT_H */