diff --git a/arch/s390/include/asm/io.h b/arch/s390/include/asm/io.h
index 00704fc8a54b..0fbc992d7a5e 100644
--- a/arch/s390/include/asm/io.h
+++ b/arch/s390/include/asm/io.h
@@ -81,6 +81,13 @@ static inline void __iowrite32_copy(void __iomem *to, const void *from,
 }
 #define __iowrite32_copy __iowrite32_copy
 
+static inline void __iowrite64_copy(void __iomem *to, const void *from,
+				    size_t count)
+{
+	zpci_memcpy_toio(to, from, count * 8);
+}
+#define __iowrite64_copy __iowrite64_copy
+
 #endif /* CONFIG_PCI */
 
 #include <asm-generic/io.h>
diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c
index 26afde0d1ed3..0de0f6e405b5 100644
--- a/arch/s390/pci/pci.c
+++ b/arch/s390/pci/pci.c
@@ -250,12 +250,6 @@ resource_size_t pcibios_align_resource(void *data, const struct resource *res,
 	return 0;
 }
 
-/* combine single writes by using store-block insn */
-void __iowrite64_copy(void __iomem *to, const void *from, size_t count)
-{
-	zpci_memcpy_toio(to, from, count * 8);
-}
-
 void __iomem *ioremap_prot(phys_addr_t phys_addr, size_t size,
 			   unsigned long prot)
 {
diff --git a/include/linux/io.h b/include/linux/io.h
index ce86120ce9d5..42e132808f00 100644
--- a/include/linux/io.h
+++ b/include/linux/io.h
@@ -21,7 +21,10 @@ void __iowrite32_copy(void __iomem *to, const void *from, size_t count);
 #endif
 
 void __ioread32_copy(void *to, const void __iomem *from, size_t count);
+
+#ifndef __iowrite64_copy
 void __iowrite64_copy(void __iomem *to, const void *from, size_t count);
+#endif
 
 #ifdef CONFIG_MMU
 int ioremap_page_range(unsigned long addr, unsigned long end,
diff --git a/lib/iomap_copy.c b/lib/iomap_copy.c
index 8ddcbb53507d..2fd5712fb7c0 100644
--- a/lib/iomap_copy.c
+++ b/lib/iomap_copy.c
@@ -60,9 +60,8 @@ EXPORT_SYMBOL_GPL(__ioread32_copy);
  * time.  Order of access is not guaranteed, nor is a memory barrier
  * performed afterwards.
  */
-void __attribute__((weak)) __iowrite64_copy(void __iomem *to,
-					    const void *from,
-					    size_t count)
+#ifndef __iowrite64_copy
+void __iowrite64_copy(void __iomem *to, const void *from, size_t count)
 {
 #ifdef CONFIG_64BIT
 	u64 __iomem *dst = to;
@@ -75,5 +74,5 @@ void __attribute__((weak)) __iowrite64_copy(void __iomem *to,
 	__iowrite32_copy(to, from, count * 2);
 #endif
 }
-
 EXPORT_SYMBOL_GPL(__iowrite64_copy);
+#endif