diff --git a/arch/s390/include/asm/stacktrace.h b/arch/s390/include/asm/stacktrace.h
index 25e833c..1966422 100644
--- a/arch/s390/include/asm/stacktrace.h
+++ b/arch/s390/include/asm/stacktrace.h
@@ -189,4 +189,51 @@ static __always_inline unsigned long get_stack_pointer(struct task_struct *task,
 	(rettype)r2;							\
 })
 
+/*
+ * Use call_nodat() to call a function with DAT disabled.
+ * Proper sign and zero extension of function arguments is done.
+ * Usage:
+ *
+ * rc = call_nodat(nr, rettype, fn, t1, a1, t2, a2, ...)
+ *
+ * - nr specifies the number of function arguments of fn.
+ * - fn is the function to be called, where fn is a physical address.
+ * - rettype is the return type of fn.
+ * - t1, a1, ... are pairs, where t1 must match the type of the first
+ *   argument of fn, t2 the second, etc. a1 is the corresponding
+ *   first function argument (not name), etc.
+ *
+ * fn() is called with standard C function call ABI, with the exception
+ * that no useful stackframe or stackpointer is passed via register 15.
+ * Therefore the called function must not use r15 to access the stack.
+ */
+#define call_nodat(nr, rettype, fn, ...)				\
+({									\
+	rettype (*__fn)(CALL_PARM_##nr(__VA_ARGS__)) = (fn);		\
+	psw_t psw_enter, psw_leave;					\
+	CALL_LARGS_##nr(__VA_ARGS__);					\
+	CALL_REGS_##nr;							\
+									\
+	CALL_TYPECHECK_##nr(__VA_ARGS__);				\
+	psw_enter.mask = PSW_KERNEL_BITS & ~PSW_MASK_DAT;		\
+	psw_enter.addr = (unsigned long)__fn;				\
+	asm volatile(							\
+		"	epsw	0,1\n"					\
+		"	risbg	1,0,0,31,32\n"				\
+		"	larl	7,1f\n"					\
+		"	stg	1,%[psw_leave]\n"			\
+		"	stg	7,8+%[psw_leave]\n"			\
+		"	la	7,%[psw_leave]\n"			\
+		"	lra	7,0(7)\n"				\
+		"	larl	1,0f\n"					\
+		"	lra	14,0(1)\n"				\
+		"	lpswe	%[psw_enter]\n"				\
+		"0:	lpswe	0(7)\n"					\
+		"1:\n"							\
+		: CALL_FMT_##nr, [psw_leave] "=Q" (psw_leave)		\
+		: [psw_enter] "Q" (psw_enter)				\
+		: "7", CALL_CLOBBER_##nr);				\
+	(rettype)r2;							\
+})
+
 #endif /* _ASM_S390_STACKTRACE_H */
diff --git a/arch/s390/kernel/machine_kexec.c b/arch/s390/kernel/machine_kexec.c
index fb88767..f5d8abf 100644
--- a/arch/s390/kernel/machine_kexec.c
+++ b/arch/s390/kernel/machine_kexec.c
@@ -30,6 +30,7 @@
 #include <asm/sclp.h>
 
 typedef void (*relocate_kernel_t)(unsigned long, unsigned long, unsigned long);
+typedef int (*purgatory_t)(int);
 
 extern const unsigned char relocate_kernel[];
 extern const unsigned long long relocate_kernel_len;
@@ -40,11 +41,14 @@ extern const unsigned long long relocate_kernel_len;
  * Reset the system, copy boot CPU registers to absolute zero,
  * and jump to the kdump image
  */
-static void __do_machine_kdump(void *image)
+static void __do_machine_kdump(void *data)
 {
-	int (*start_kdump)(int);
+	struct kimage *image = data;
+	purgatory_t purgatory;
 	unsigned long prefix;
 
+	purgatory = (purgatory_t)image->start;
+
 	/* store_status() saved the prefix register to lowcore */
 	prefix = (unsigned long) S390_lowcore.prefixreg_save_area;
 
@@ -59,11 +63,9 @@ static void __do_machine_kdump(void *image)
 	memcpy(absolute_pointer(__LC_FPREGS_SAVE_AREA),
 	       phys_to_virt(prefix + __LC_FPREGS_SAVE_AREA), 512);
 
-	__load_psw_mask(PSW_MASK_BASE | PSW_DEFAULT_KEY | PSW_MASK_EA | PSW_MASK_BA);
-	start_kdump = (void *)((struct kimage *) image)->start;
-	start_kdump(1);
+	call_nodat(1, int, purgatory, int, 1);
 
-	/* Die if start_kdump returns */
+	/* Die if kdump returns */
 	disabled_wait();
 }
 
@@ -112,13 +114,9 @@ static noinline void __machine_kdump(void *image)
 
 static int do_start_kdump(struct kimage *image)
 {
-	int (*start_kdump)(int) = (void *)image->start;
-	int rc;
+	purgatory_t purgatory = (purgatory_t)image->start;
 
-	__arch_local_irq_stnsm(0xfb); /* disable DAT */
-	rc = start_kdump(0);
-	__arch_local_irq_stosm(0x04); /* enable DAT */
-	return rc;
+	return call_nodat(1, int, purgatory, int, 0);
 }
 
 #endif /* CONFIG_CRASH_DUMP */
@@ -258,8 +256,10 @@ static void __do_machine_kexec(void *data)
 		diag308_subcode |= DIAG308_FLAG_EI;
 	s390_reset_system();
 
-	__arch_local_irq_stnsm(0xfb); /* disable DAT - avoid no-execute */
-	(*(relocate_kernel_t)data_mover)(entry, image->start, diag308_subcode);
+	call_nodat(3, void, (relocate_kernel_t)data_mover,
+		   unsigned long, entry,
+		   unsigned long, image->start,
+		   unsigned long, diag308_subcode);
 
 	/* Die if kexec returns */
 	disabled_wait();