s390: enable UBSAN

This enables UBSAN for s390. We have to disable the null sanitizer
as s390 code does access memory via a null pointer (the prefix page).

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/Kconfig

@@ -74,6 +74,7 @@ config S390
 	select ARCH_HAS_GCOV_PROFILE_ALL
 	select ARCH_HAS_KCOV
 	select ARCH_HAS_SG_CHAIN
+	select ARCH_HAS_UBSAN_SANITIZE_ALL
 	select ARCH_HAVE_NMI_SAFE_CMPXCHG
 	select ARCH_INLINE_READ_LOCK
 	select ARCH_INLINE_READ_LOCK_BH
@@ -110,6 +111,7 @@ config S390
 	select ARCH_USE_CMPXCHG_LOCKREF
 	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
 	select ARCH_WANTS_PROT_NUMA_PROT_NONE
+	select ARCH_WANTS_UBSAN_NO_NULL
 	select ARCH_WANT_IPC_PARSE_VERSION
 	select BUILDTIME_EXTABLE_SORT
 	select CLONE_BACKWARDS2

arch/s390/boot/compressed/Makefile

@@ -17,6 +17,7 @@ KBUILD_CFLAGS += $(call cc-option,-mpacked-stack)
 KBUILD_CFLAGS += $(call cc-option,-ffreestanding)
 
 GCOV_PROFILE := n
+UBSAN_SANITIZE := n
 
 OBJECTS := $(addprefix $(objtree)/arch/s390/kernel/, head.o sclp.o ebcdic.o als.o)
 OBJECTS += $(obj)/head.o $(obj)/misc.o $(obj)/piggy.o

arch/s390/kernel/Makefile

@@ -48,6 +48,9 @@ AFLAGS_head.o		+= -march=z900
 endif
 GCOV_PROFILE_sclp.o := n
 GCOV_PROFILE_als.o := n
+UBSAN_SANITIZE_als.o := n
+UBSAN_SANITIZE_early.o := n
+UBSAN_SANITIZE_sclp.o := n
 
 obj-y	:= traps.o time.o process.o base.o early.o setup.o idle.o vtime.o
 obj-y	+= processor.o sys_s390.o ptrace.o signal.o cpcmd.o ebcdic.o nmi.o

arch/s390/kernel/vdso32/Makefile

@@ -24,8 +24,9 @@ obj-y += vdso32_wrapper.o
 extra-y += vdso32.lds
 CPPFLAGS_vdso32.lds += -P -C -U$(ARCH)
 
-# Disable gcov profiling for VDSO code
+# Disable gcov profiling and ubsan for VDSO code
 GCOV_PROFILE := n
+UBSAN_SANITIZE := n
 
 # Force dependency (incbin is bad)
 $(obj)/vdso32_wrapper.o : $(obj)/vdso32.so

arch/s390/kernel/vdso64/Makefile

@@ -24,8 +24,9 @@ obj-y += vdso64_wrapper.o
 extra-y += vdso64.lds
 CPPFLAGS_vdso64.lds += -P -C -U$(ARCH)
 
-# Disable gcov profiling for VDSO code
+# Disable gcov profiling and ubsan for VDSO code
 GCOV_PROFILE := n
+UBSAN_SANITIZE := n
 
 # Force dependency (incbin is bad)
 $(obj)/vdso64_wrapper.o : $(obj)/vdso64.so