s390/mm: provide simple ARCH_HAS_DEBUG_VIRTUAL support

Provide a very simple ARCH_HAS_DEBUG_VIRTUAL implementation.
For now errors are only reported for the following cases:

- Trying to translate a vmalloc or module address to a physical address

- Translating a supposed to be ZONE_DMA virtual address into a physical
  address, and the resulting physical address is larger than two GiB

Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

2 files changed, 16 insertions, 0 deletions

diff --git a/arch/s390/mm/Makefile b/arch/s390/mm/Makefile
index 352ff520fd94..f6c2db7a8669 100644
--- a/arch/s390/mm/Makefile
+++ b/arch/s390/mm/Makefile
@@ -7,6 +7,7 @@ obj-y		:= init.o fault.o extmem.o mmap.o vmem.o maccess.o
 obj-y		+= page-states.o pageattr.o pgtable.o pgalloc.o extable.o
 
 obj-$(CONFIG_CMM)		+= cmm.o
+obj-$(CONFIG_DEBUG_VIRTUAL)	+= physaddr.o
 obj-$(CONFIG_HUGETLB_PAGE)	+= hugetlbpage.o
 obj-$(CONFIG_PTDUMP_CORE)	+= dump_pagetables.o
 obj-$(CONFIG_PGSTE)		+= gmap.o
diff --git a/arch/s390/mm/physaddr.c b/arch/s390/mm/physaddr.c
new file mode 100644
index 000000000000..59de866c72d9
--- /dev/null
+++ b/arch/s390/mm/physaddr.c
@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/mmdebug.h>
+#include <linux/export.h>
+#include <linux/mm.h>
+#include <asm/page.h>
+
+unsigned long __phys_addr(unsigned long x, bool is_31bit)
+{
+	VIRTUAL_BUG_ON(is_vmalloc_or_module_addr((void *)(x)));
+	x = __pa_nodebug(x);
+	if (is_31bit)
+		VIRTUAL_BUG_ON(x >> 31);
+	return x;
+}
+EXPORT_SYMBOL(__phys_addr);