diff --git a/arch/s390/boot/Makefile b/arch/s390/boot/Makefile
index e1f82d118bc9..10b75e053a6f 100644
--- a/arch/s390/boot/Makefile
+++ b/arch/s390/boot/Makefile
@@ -31,7 +31,7 @@ CFLAGS_sclp_early_core.o += -I$(srctree)/drivers/s390/char
 CFLAGS_string.o = -ffreestanding
 
 obj-y	:= head.o als.o startup.o physmem_info.o ipl_parm.o ipl_report.o vmem.o
-obj-y	+= string.o ebcdic.o sclp_early_core.o mem.o ipl_vmparm.o cmdline.o
+obj-y	+= string.o ebcdic.o sclp_early_core.o ipl_vmparm.o cmdline.o
 obj-y	+= version.o pgm_check.o ctype.o ipl_data.o relocs.o alternative.o
 obj-y	+= uv.o printk.o trampoline.o
 obj-$(CONFIG_RANDOMIZE_BASE)	+= kaslr.o
diff --git a/arch/s390/boot/mem.S b/arch/s390/boot/mem.S
deleted file mode 100644
index b33463633f03..000000000000
--- a/arch/s390/boot/mem.S
+++ /dev/null
@@ -1,2 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#include "../lib/mem.S"
diff --git a/arch/s390/boot/string.c b/arch/s390/boot/string.c
index bd68161434a6..e4ad196cb720 100644
--- a/arch/s390/boot/string.c
+++ b/arch/s390/boot/string.c
@@ -43,11 +43,7 @@ ssize_t sized_strscpy(char *dst, const char *src, size_t count)
 
 void *memset64(uint64_t *s, uint64_t v, size_t count)
 {
-	uint64_t *xs = s;
-
-	while (count--)
-		*xs++ = v;
-	return s;
+	return __memset64(s, v, count * sizeof(v));
 }
 
 char *skip_spaces(const char *str)
diff --git a/arch/s390/lib/Makefile b/arch/s390/lib/Makefile
index c82aedef0272..aa6cc6a1fe88 100644
--- a/arch/s390/lib/Makefile
+++ b/arch/s390/lib/Makefile
@@ -10,7 +10,6 @@ CFLAGS_string.o = -ffreestanding
 
 lib-y += delay.o string.o uaccess.o find.o spinlock.o tishift.o
 lib-y += csum-partial.o
-obj-y += mem.o
 lib-$(CONFIG_KPROBES) += probes.o
 lib-$(CONFIG_UPROBES) += probes.o
 obj-$(CONFIG_S390_KPROBES_SANITY_TEST) += test_kprobes_s390.o
diff --git a/arch/s390/lib/mem.S b/arch/s390/lib/mem.S
deleted file mode 100644
index d2e1ca87a568..000000000000
--- a/arch/s390/lib/mem.S
+++ /dev/null
@@ -1,57 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * String handling functions.
- *
- * Copyright IBM Corp. 2012
- */
-
-#include <linux/export.h>
-#include <linux/linkage.h>
-#include <asm/nospec-insn.h>
-
-	GEN_BR_THUNK %r14
-
-/*
- * __memset16/32/64
- *
- * void *__memset16(uint16_t *s, uint16_t v, size_t count)
- * void *__memset32(uint32_t *s, uint32_t v, size_t count)
- * void *__memset64(uint64_t *s, uint64_t v, size_t count)
- */
-.macro __MEMSET bits,bytes,insn
-SYM_FUNC_START(__memset\bits)
-	ltgr	%r4,%r4
-	jz	.L__memset_exit\bits
-	cghi	%r4,\bytes
-	je	.L__memset_store\bits
-	aghi	%r4,-(\bytes+1)
-	srlg	%r5,%r4,8
-	ltgr	%r5,%r5
-	lgr	%r1,%r2
-	jz	.L__memset_remainder\bits
-.L__memset_loop\bits:
-	\insn	%r3,0(%r1)
-	mvc	\bytes(256-\bytes,%r1),0(%r1)
-	la	%r1,256(%r1)
-	brctg	%r5,.L__memset_loop\bits
-.L__memset_remainder\bits:
-	\insn	%r3,0(%r1)
-	exrl	%r4,.L__memset_mvc\bits
-	BR_EX	%r14
-.L__memset_store\bits:
-	\insn	%r3,0(%r2)
-.L__memset_exit\bits:
-	BR_EX	%r14
-.L__memset_mvc\bits:
-	mvc	\bytes(1,%r1),0(%r1)
-SYM_FUNC_END(__memset\bits)
-.endm
-
-__MEMSET 16,2,sth
-EXPORT_SYMBOL(__memset16)
-
-__MEMSET 32,4,st
-EXPORT_SYMBOL(__memset32)
-
-__MEMSET 64,8,stg
-EXPORT_SYMBOL(__memset64)
diff --git a/arch/s390/lib/string.c b/arch/s390/lib/string.c
index 056ea2027ddd..cb65b8f5392a 100644
--- a/arch/s390/lib/string.c
+++ b/arch/s390/lib/string.c
@@ -158,6 +158,53 @@ EXPORT_SYMBOL(__memcpy);
 EXPORT_SYMBOL(memcpy);
 #endif
 
+#define DEFINE_MEMSET(_bits, _bytes, _type)					\
+void *__memset##_bits(_type *s, _type v, size_t n)				\
+{										\
+	_type *xs = s;								\
+										\
+	if (!n)									\
+		return s;							\
+	while (n >= 256) {							\
+		*xs = v;							\
+		asm volatile(							\
+			"	mvc	%[_b](256-%[_b],%[xs]),0(%[xs])\n"	\
+			:							\
+			: [xs] "a" (xs), [_b] "i" (_bytes)			\
+			: "memory");						\
+		xs = (_type *)((char *)xs + 256);				\
+		n -= 256;							\
+	}									\
+	if (!n)									\
+		return s;							\
+	*xs = v;								\
+	if (n == _bytes)							\
+		return s;							\
+	n -= _bytes + 1;							\
+	asm volatile(								\
+		"	exrl	 %[n],1f\n"					\
+		"	j	 2f\n"						\
+		"1:	mvc	 %[_b](1,%[xs]),0(%[xs])\n"			\
+		"2:"								\
+		:								\
+		: [n] "a" (n), [xs] "a" (xs), [_b] "i" (_bytes)			\
+		: "memory");							\
+	return s;								\
+}										\
+EXPORT_SYMBOL(__memset##_bits)
+
+#ifdef __HAVE_ARCH_MEMSET16
+DEFINE_MEMSET(16, 2, uint16_t);
+#endif
+
+#ifdef __HAVE_ARCH_MEMSET32
+DEFINE_MEMSET(32, 4, uint32_t);
+#endif
+
+#ifdef __HAVE_ARCH_MEMSET64
+DEFINE_MEMSET(64, 8, uint64_t);
+#endif
+
 /*
  * Helper functions to find the end of a string
  */
diff --git a/arch/s390/purgatory/Makefile b/arch/s390/purgatory/Makefile
index f55764d0c49e..e74410bb1b88 100644
--- a/arch/s390/purgatory/Makefile
+++ b/arch/s390/purgatory/Makefile
@@ -1,6 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 
-purgatory-y := head.o purgatory.o string.o sha256.o mem.o
+purgatory-y := head.o purgatory.o string.o sha256.o
 
 targets += $(purgatory-y) purgatory.lds purgatory purgatory.chk purgatory.ro
 PURGATORY_OBJS = $(addprefix $(obj)/,$(purgatory-y))
@@ -10,9 +10,6 @@ $(obj)/sha256.o: $(srctree)/lib/crypto/sha256.c FORCE
 
 CFLAGS_sha256.o := -D__NO_FORTIFY
 
-$(obj)/mem.o: $(srctree)/arch/s390/lib/mem.S FORCE
-	$(call if_changed_rule,as_o_S)
-
 CC_FLAGS_MARCH_MINIMUM := -march=z10
 
 KBUILD_CFLAGS := $(CC_FLAGS_DIALECT) -fno-strict-aliasing -Wall -Wstrict-prototypes