1 files changed, 139 insertions, 0 deletions
diff --git a/arch/s390/include/asm/mmu_context.h b/arch/s390/include/asm/mmu_context.h
new file mode 100644
index 000000000..c9f3d8a52
--- /dev/null
+++ b/arch/s390/include/asm/mmu_context.h
@@ -0,0 +1,139 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ *  S390 version
+ *
+ *  Derived from "include/asm-i386/mmu_context.h"
+ */
+
+#ifndef __S390_MMU_CONTEXT_H
+#define __S390_MMU_CONTEXT_H
+
+#include <asm/pgalloc.h>
+#include <linux/uaccess.h>
+#include <linux/mm_types.h>
+#include <asm/tlbflush.h>
+#include <asm/ctl_reg.h>
+#include <asm-generic/mm_hooks.h>
+
+static inline int init_new_context(struct task_struct *tsk,
+				   struct mm_struct *mm)
+{
+	unsigned long asce_type, init_entry;
+
+	spin_lock_init(&mm->context.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.flush_count, 0);
+	atomic_set(&mm->context.is_protected, 0);
+	mm->context.gmap_asce = 0;
+	mm->context.flush_mm = 0;
+#ifdef CONFIG_PGSTE
+	mm->context.alloc_pgste = page_table_allocate_pgste ||
+		test_thread_flag(TIF_PGSTE) ||
+		(current->mm && current->mm->context.alloc_pgste);
+	mm->context.has_pgste = 0;
+	mm->context.uses_skeys = 0;
+	mm->context.uses_cmm = 0;
+	mm->context.allow_gmap_hpage_1m = 0;
+#endif
+	switch (mm->context.asce_limit) {
+	default:
+		/*
+		 * context created by exec, the value of asce_limit can
+		 * only be zero in this case
+		 */
+		VM_BUG_ON(mm->context.asce_limit);
+		/* continue as 3-level task */
+		mm->context.asce_limit = _REGION2_SIZE;
+		fallthrough;
+	case _REGION2_SIZE:
+		/* forked 3-level task */
+		init_entry = _REGION3_ENTRY_EMPTY;
+		asce_type = _ASCE_TYPE_REGION3;
+		break;
+	case TASK_SIZE_MAX:
+		/* forked 5-level task */
+		init_entry = _REGION1_ENTRY_EMPTY;
+		asce_type = _ASCE_TYPE_REGION1;
+		break;
+	case _REGION1_SIZE:
+		/* forked 4-level task */
+		init_entry = _REGION2_ENTRY_EMPTY;
+		asce_type = _ASCE_TYPE_REGION2;
+		break;
+	}
+	mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
+			   _ASCE_USER_BITS | asce_type;
+	crst_table_init((unsigned long *) mm->pgd, init_entry);
+	return 0;
+}
+
+#define destroy_context(mm)             do { } while (0)
+
+static inline void set_user_asce(struct mm_struct *mm)
+{
+	S390_lowcore.user_asce = mm->context.asce;
+	__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.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;
+	cpumask_set_cpu(cpu, &next->context.cpu_attach_mask);
+	/* 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);
+	}
+	if (prev != next)
+		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;
+
+	if (mm) {
+		preempt_disable();
+		while (atomic_read(&mm->context.flush_count))
+			cpu_relax();
+		cpumask_set_cpu(smp_processor_id(), mm_cpumask(mm));
+		__tlb_flush_mm_lazy(mm);
+		preempt_enable();
+	}
+	set_fs(current->thread.mm_segment);
+}
+
+#define enter_lazy_tlb(mm,tsk)	do { } while (0)
+#define deactivate_mm(tsk,mm)	do { } while (0)
+
+static inline void activate_mm(struct mm_struct *prev,
+                               struct mm_struct *next)
+{
+	switch_mm(prev, next, current);
+	cpumask_set_cpu(smp_processor_id(), mm_cpumask(next));
+	set_user_asce(next);
+}
+
+#endif /* __S390_MMU_CONTEXT_H */