diff --git a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c
index a3acd8e..355f7a3 100644
--- a/arch/s390/kernel/process.c
+++ b/arch/s390/kernel/process.c
@@ -32,6 +32,7 @@
 #include <linux/elfcore.h>
 #include <linux/kernel_stat.h>
 #include <linux/syscalls.h>
+#include <asm/compat.h>
 #include <asm/uaccess.h>
 #include <asm/pgtable.h>
 #include <asm/system.h>
@@ -204,7 +205,7 @@
 	save_fp_regs(&p->thread.fp_regs);
 	/* Set a new TLS ?  */
 	if (clone_flags & CLONE_SETTLS) {
-		if (test_thread_flag(TIF_31BIT)) {
+		if (is_compat_task()) {
 			p->thread.acrs[0] = (unsigned int) regs->gprs[6];
 		} else {
 			p->thread.acrs[0] = (unsigned int)(regs->gprs[6] >> 32);
diff --git a/arch/s390/kernel/ptrace.c b/arch/s390/kernel/ptrace.c
index 75c496f..99eef17 100644
--- a/arch/s390/kernel/ptrace.c
+++ b/arch/s390/kernel/ptrace.c
@@ -36,7 +36,7 @@
 #include <linux/elf.h>
 #include <linux/regset.h>
 #include <linux/tracehook.h>
-
+#include <linux/compat.h>
 #include <asm/segment.h>
 #include <asm/page.h>
 #include <asm/pgtable.h>
@@ -69,7 +69,7 @@
 	if (per_info->single_step) {
 		per_info->control_regs.bits.starting_addr = 0;
 #ifdef CONFIG_COMPAT
-		if (test_thread_flag(TIF_31BIT))
+		if (is_compat_task())
 			per_info->control_regs.bits.ending_addr = 0x7fffffffUL;
 		else
 #endif
@@ -482,8 +482,7 @@
 {
 	__u32 tmp;
 
-	if (!test_thread_flag(TIF_31BIT) ||
-	    (addr & 3) || addr > sizeof(struct user) - 3)
+	if (!is_compat_task() || (addr & 3) || addr > sizeof(struct user) - 3)
 		return -EIO;
 
 	tmp = __peek_user_compat(child, addr);
@@ -584,8 +583,7 @@
 static int poke_user_compat(struct task_struct *child,
 			    addr_t addr, addr_t data)
 {
-	if (!test_thread_flag(TIF_31BIT) ||
-	    (addr & 3) || addr > sizeof(struct user32) - 3)
+	if (!is_compat_task() || (addr & 3) || addr > sizeof(struct user32) - 3)
 		return -EIO;
 
 	return __poke_user_compat(child, addr, data);
@@ -660,7 +658,7 @@
 	}
 
 	if (unlikely(current->audit_context))
-		audit_syscall_entry(test_thread_flag(TIF_31BIT) ?
+		audit_syscall_entry(is_compat_task() ?
 					AUDIT_ARCH_S390 : AUDIT_ARCH_S390X,
 				    regs->gprs[2], regs->orig_gpr2,
 				    regs->gprs[3], regs->gprs[4],
diff --git a/arch/s390/kernel/signal.c b/arch/s390/kernel/signal.c
index 3cf74c3..062bd64 100644
--- a/arch/s390/kernel/signal.c
+++ b/arch/s390/kernel/signal.c
@@ -26,6 +26,7 @@
 #include <linux/binfmts.h>
 #include <linux/tracehook.h>
 #include <linux/syscalls.h>
+#include <linux/compat.h>
 #include <asm/ucontext.h>
 #include <asm/uaccess.h>
 #include <asm/lowcore.h>
@@ -482,7 +483,7 @@
 		/* Whee!  Actually deliver the signal.  */
 		int ret;
 #ifdef CONFIG_COMPAT
-		if (test_thread_flag(TIF_31BIT)) {
+		if (is_compat_task()) {
 			ret = handle_signal32(signr, &ka, &info, oldset, regs);
 	        }
 		else
diff --git a/arch/s390/kernel/vdso.c b/arch/s390/kernel/vdso.c
index 7b76ee4..45e1708 100644
--- a/arch/s390/kernel/vdso.c
+++ b/arch/s390/kernel/vdso.c
@@ -22,7 +22,7 @@
 #include <linux/elf.h>
 #include <linux/security.h>
 #include <linux/bootmem.h>
-
+#include <linux/compat.h>
 #include <asm/pgtable.h>
 #include <asm/system.h>
 #include <asm/processor.h>
@@ -214,7 +214,7 @@
 	vdso_pagelist = vdso64_pagelist;
 	vdso_pages = vdso64_pages;
 #ifdef CONFIG_COMPAT
-	if (test_thread_flag(TIF_31BIT)) {
+	if (is_compat_task()) {
 		vdso_pagelist = vdso32_pagelist;
 		vdso_pages = vdso32_pages;
 	}