diff --git a/arch/s390/kernel/syscall.c b/arch/s390/kernel/syscall.c
index c8df656b08bc..535f3922ffa9 100644
--- a/arch/s390/kernel/syscall.c
+++ b/arch/s390/kernel/syscall.c
@@ -82,47 +82,10 @@ SYSCALL_DEFINE0(ni_syscall)
 	return -ENOSYS;
 }
 
-static void do_syscall(struct pt_regs *regs)
+void noinstr __do_syscall(struct pt_regs *regs, int per_trap)
 {
 	unsigned long nr;
 
-	nr = regs->int_code & 0xffff;
-	if (!nr) {
-		nr = regs->gprs[1] & 0xffff;
-		regs->int_code &= ~0xffffUL;
-		regs->int_code |= nr;
-	}
-
-	regs->gprs[2] = nr;
-
-	if (nr == __NR_restart_syscall && !(current->restart_block.arch_data & 1)) {
-		regs->psw.addr = current->restart_block.arch_data;
-		current->restart_block.arch_data = 1;
-	}
-	nr = syscall_enter_from_user_mode_work(regs, nr);
-
-	/*
-	 * In the s390 ptrace ABI, both the syscall number and the return value
-	 * use gpr2. However, userspace puts the syscall number either in the
-	 * svc instruction itself, or uses gpr1. To make at least skipping syscalls
-	 * work, the ptrace code sets PIF_SYSCALL_RET_SET, which is checked here
-	 * and if set, the syscall will be skipped.
-	 */
-
-	if (unlikely(test_and_clear_pt_regs_flag(regs, PIF_SYSCALL_RET_SET)))
-		goto out;
-	regs->gprs[2] = -ENOSYS;
-	if (likely(nr >= NR_syscalls))
-		goto out;
-	do {
-		regs->gprs[2] = current->thread.sys_call_table[nr](regs);
-	} while (test_and_clear_pt_regs_flag(regs, PIF_EXECVE_PGSTE_RESTART));
-out:
-	syscall_exit_to_user_mode_work(regs);
-}
-
-void noinstr __do_syscall(struct pt_regs *regs, int per_trap)
-{
 	add_random_kstack_offset();
 	enter_from_user_mode(regs);
 	regs->psw = get_lowcore()->svc_old_psw;
@@ -130,15 +93,39 @@ void noinstr __do_syscall(struct pt_regs *regs, int per_trap)
 	update_timer_sys();
 	if (cpu_has_bear())
 		current->thread.last_break = regs->last_break;
-
 	local_irq_enable();
 	regs->orig_gpr2 = regs->gprs[2];
-
-	if (per_trap)
+	if (unlikely(per_trap))
 		set_thread_flag(TIF_PER_TRAP);
-
 	regs->flags = 0;
 	set_pt_regs_flag(regs, PIF_SYSCALL);
-	do_syscall(regs);
-	exit_to_user_mode();
+	nr = regs->int_code & 0xffff;
+	if (likely(!nr)) {
+		nr = regs->gprs[1] & 0xffff;
+		regs->int_code &= ~0xffffUL;
+		regs->int_code |= nr;
+	}
+	regs->gprs[2] = nr;
+	if (nr == __NR_restart_syscall && !(current->restart_block.arch_data & 1)) {
+		regs->psw.addr = current->restart_block.arch_data;
+		current->restart_block.arch_data = 1;
+	}
+	nr = syscall_enter_from_user_mode_work(regs, nr);
+	/*
+	 * In the s390 ptrace ABI, both the syscall number and the return value
+	 * use gpr2. However, userspace puts the syscall number either in the
+	 * svc instruction itself, or uses gpr1. To make at least skipping syscalls
+	 * work, the ptrace code sets PIF_SYSCALL_RET_SET, which is checked here
+	 * and if set, the syscall will be skipped.
+	 */
+	if (unlikely(test_and_clear_pt_regs_flag(regs, PIF_SYSCALL_RET_SET)))
+		goto out;
+	regs->gprs[2] = -ENOSYS;
+	if (unlikely(nr >= NR_syscalls))
+		goto out;
+	do {
+		regs->gprs[2] = current->thread.sys_call_table[nr](regs);
+	} while (test_and_clear_pt_regs_flag(regs, PIF_EXECVE_PGSTE_RESTART));
+out:
+	syscall_exit_to_user_mode(regs);
 }