2 files changed, 133 insertions, 10 deletions

diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index 7b0bb475c166..7bd86ebc882f 100644
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -38,6 +38,7 @@
 #include <asm/irq.h>
 #include <asm/mmu_context.h>
 #include <asm/facility.h>
+#include <asm/uv.h>
 #include "../kernel/entry.h"
 
 #define __FAIL_ADDR_MASK -4096L
@@ -816,3 +817,80 @@ out_extint:
 early_initcall(pfault_irq_init);
 
 #endif /* CONFIG_PFAULT */
+
+#if IS_ENABLED(CONFIG_PGSTE)
+void do_secure_storage_access(struct pt_regs *regs)
+{
+	unsigned long addr = regs->int_parm_long & __FAIL_ADDR_MASK;
+	struct vm_area_struct *vma;
+	struct mm_struct *mm;
+	struct page *page;
+	int rc;
+
+	switch (get_fault_type(regs)) {
+	case USER_FAULT:
+		mm = current->mm;
+		down_read(&mm->mmap_sem);
+		vma = find_vma(mm, addr);
+		if (!vma) {
+			up_read(&mm->mmap_sem);
+			do_fault_error(regs, VM_READ | VM_WRITE, VM_FAULT_BADMAP);
+			break;
+		}
+		page = follow_page(vma, addr, FOLL_WRITE | FOLL_GET);
+		if (IS_ERR_OR_NULL(page)) {
+			up_read(&mm->mmap_sem);
+			break;
+		}
+		if (arch_make_page_accessible(page))
+			send_sig(SIGSEGV, current, 0);
+		put_page(page);
+		up_read(&mm->mmap_sem);
+		break;
+	case KERNEL_FAULT:
+		page = phys_to_page(addr);
+		if (unlikely(!try_get_page(page)))
+			break;
+		rc = arch_make_page_accessible(page);
+		put_page(page);
+		if (rc)
+			BUG();
+		break;
+	case VDSO_FAULT:
+		/* fallthrough */
+	case GMAP_FAULT:
+		/* fallthrough */
+	default:
+		do_fault_error(regs, VM_READ | VM_WRITE, VM_FAULT_BADMAP);
+		WARN_ON_ONCE(1);
+	}
+}
+NOKPROBE_SYMBOL(do_secure_storage_access);
+
+void do_non_secure_storage_access(struct pt_regs *regs)
+{
+	unsigned long gaddr = regs->int_parm_long & __FAIL_ADDR_MASK;
+	struct gmap *gmap = (struct gmap *)S390_lowcore.gmap;
+
+	if (get_fault_type(regs) != GMAP_FAULT) {
+		do_fault_error(regs, VM_READ | VM_WRITE, VM_FAULT_BADMAP);
+		WARN_ON_ONCE(1);
+		return;
+	}
+
+	if (gmap_convert_to_secure(gmap, gaddr) == -EINVAL)
+		send_sig(SIGSEGV, current, 0);
+}
+NOKPROBE_SYMBOL(do_non_secure_storage_access);
+
+#else
+void do_secure_storage_access(struct pt_regs *regs)
+{
+	default_trap_handler(regs);
+}
+
+void do_non_secure_storage_access(struct pt_regs *regs)
+{
+	default_trap_handler(regs);
+}
+#endif
diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c
index edcdca97e85e..27926a06df32 100644
--- a/arch/s390/mm/gmap.c
+++ b/arch/s390/mm/gmap.c
@@ -2548,6 +2548,22 @@ int s390_enable_sie(void)
 }
 EXPORT_SYMBOL_GPL(s390_enable_sie);
 
+int gmap_mark_unmergeable(void)
+{
+	struct mm_struct *mm = current->mm;
+	struct vm_area_struct *vma;
+
+	for (vma = mm->mmap; vma; vma = vma->vm_next) {
+		if (ksm_madvise(vma, vma->vm_start, vma->vm_end,
+				MADV_UNMERGEABLE, &vma->vm_flags)) {
+			return -ENOMEM;
+		}
+	}
+	mm->def_flags &= ~VM_MERGEABLE;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(gmap_mark_unmergeable);
+
 /*
  * Enable storage key handling from now on and initialize the storage
  * keys with the default key.
@@ -2593,7 +2609,6 @@ static const struct mm_walk_ops enable_skey_walk_ops = {
 int s390_enable_skey(void)
 {
 	struct mm_struct *mm = current->mm;
-	struct vm_area_struct *vma;
 	int rc = 0;
 
 	down_write(&mm->mmap_sem);
@@ -2601,16 +2616,11 @@ int s390_enable_skey(void)
 		goto out_up;
 
 	mm->context.uses_skeys = 1;
-	for (vma = mm->mmap; vma; vma = vma->vm_next) {
-		if (ksm_madvise(vma, vma->vm_start, vma->vm_end,
-				MADV_UNMERGEABLE, &vma->vm_flags)) {
-			mm->context.uses_skeys = 0;
-			rc = -ENOMEM;
-			goto out_up;
-		}
+	rc = gmap_mark_unmergeable();
+	if (rc) {
+		mm->context.uses_skeys = 0;
+		goto out_up;
 	}
-	mm->def_flags &= ~VM_MERGEABLE;
-
 	walk_page_range(mm, 0, TASK_SIZE, &enable_skey_walk_ops, NULL);
 
 out_up:
@@ -2640,3 +2650,38 @@ void s390_reset_cmma(struct mm_struct *mm)
 	up_write(&mm->mmap_sem);
 }
 EXPORT_SYMBOL_GPL(s390_reset_cmma);
+
+/*
+ * make inaccessible pages accessible again
+ */
+static int __s390_reset_acc(pte_t *ptep, unsigned long addr,
+			    unsigned long next, struct mm_walk *walk)
+{
+	pte_t pte = READ_ONCE(*ptep);
+
+	if (pte_present(pte))
+		WARN_ON_ONCE(uv_convert_from_secure(pte_val(pte) & PAGE_MASK));
+	return 0;
+}
+
+static const struct mm_walk_ops reset_acc_walk_ops = {
+	.pte_entry		= __s390_reset_acc,
+};
+
+#include <linux/sched/mm.h>
+void s390_reset_acc(struct mm_struct *mm)
+{
+	/*
+	 * we might be called during
+	 * reset:                             we walk the pages and clear
+	 * close of all kvm file descriptors: we walk the pages and clear
+	 * exit of process on fd closure:     vma already gone, do nothing
+	 */
+	if (!mmget_not_zero(mm))
+		return;
+	down_read(&mm->mmap_sem);
+	walk_page_range(mm, 0, TASK_SIZE, &reset_acc_walk_ops, NULL);
+	up_read(&mm->mmap_sem);
+	mmput(mm);
+}
+EXPORT_SYMBOL_GPL(s390_reset_acc);