v4.19.13 snapshot.
diff --git a/arch/s390/lib/mem.S b/arch/s390/lib/mem.S
new file mode 100644
index 0000000..40c4d59
--- /dev/null
+++ b/arch/s390/lib/mem.S
@@ -0,0 +1,184 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * String handling functions.
+ *
+ * Copyright IBM Corp. 2012
+ */
+
+#include <linux/linkage.h>
+#include <asm/export.h>
+#include <asm/nospec-insn.h>
+
+ GEN_BR_THUNK %r14
+
+/*
+ * void *memmove(void *dest, const void *src, size_t n)
+ */
+ENTRY(memmove)
+ ltgr %r4,%r4
+ lgr %r1,%r2
+ jz .Lmemmove_exit
+ aghi %r4,-1
+ clgr %r2,%r3
+ jnh .Lmemmove_forward
+ la %r5,1(%r4,%r3)
+ clgr %r2,%r5
+ jl .Lmemmove_reverse
+.Lmemmove_forward:
+ srlg %r0,%r4,8
+ ltgr %r0,%r0
+ jz .Lmemmove_forward_remainder
+.Lmemmove_forward_loop:
+ mvc 0(256,%r1),0(%r3)
+ la %r1,256(%r1)
+ la %r3,256(%r3)
+ brctg %r0,.Lmemmove_forward_loop
+.Lmemmove_forward_remainder:
+ larl %r5,.Lmemmove_mvc
+ ex %r4,0(%r5)
+.Lmemmove_exit:
+ BR_EX %r14
+.Lmemmove_reverse:
+ ic %r0,0(%r4,%r3)
+ stc %r0,0(%r4,%r1)
+ brctg %r4,.Lmemmove_reverse
+ ic %r0,0(%r4,%r3)
+ stc %r0,0(%r4,%r1)
+ BR_EX %r14
+.Lmemmove_mvc:
+ mvc 0(1,%r1),0(%r3)
+EXPORT_SYMBOL(memmove)
+
+/*
+ * memset implementation
+ *
+ * This code corresponds to the C construct below. We do distinguish
+ * between clearing (c == 0) and setting a memory array (c != 0) simply
+ * because nearly all memset invocations in the kernel clear memory and
+ * the xc instruction is preferred in such cases.
+ *
+ * void *memset(void *s, int c, size_t n)
+ * {
+ * if (likely(c == 0))
+ * return __builtin_memset(s, 0, n);
+ * return __builtin_memset(s, c, n);
+ * }
+ */
+ENTRY(memset)
+ ltgr %r4,%r4
+ jz .Lmemset_exit
+ ltgr %r3,%r3
+ jnz .Lmemset_fill
+ aghi %r4,-1
+ srlg %r3,%r4,8
+ ltgr %r3,%r3
+ lgr %r1,%r2
+ jz .Lmemset_clear_remainder
+.Lmemset_clear_loop:
+ xc 0(256,%r1),0(%r1)
+ la %r1,256(%r1)
+ brctg %r3,.Lmemset_clear_loop
+.Lmemset_clear_remainder:
+ larl %r3,.Lmemset_xc
+ ex %r4,0(%r3)
+.Lmemset_exit:
+ BR_EX %r14
+.Lmemset_fill:
+ cghi %r4,1
+ lgr %r1,%r2
+ je .Lmemset_fill_exit
+ aghi %r4,-2
+ srlg %r5,%r4,8
+ ltgr %r5,%r5
+ jz .Lmemset_fill_remainder
+.Lmemset_fill_loop:
+ stc %r3,0(%r1)
+ mvc 1(255,%r1),0(%r1)
+ la %r1,256(%r1)
+ brctg %r5,.Lmemset_fill_loop
+.Lmemset_fill_remainder:
+ stc %r3,0(%r1)
+ larl %r5,.Lmemset_mvc
+ ex %r4,0(%r5)
+ BR_EX %r14
+.Lmemset_fill_exit:
+ stc %r3,0(%r1)
+ BR_EX %r14
+.Lmemset_xc:
+ xc 0(1,%r1),0(%r1)
+.Lmemset_mvc:
+ mvc 1(1,%r1),0(%r1)
+EXPORT_SYMBOL(memset)
+
+/*
+ * memcpy implementation
+ *
+ * void *memcpy(void *dest, const void *src, size_t n)
+ */
+ENTRY(memcpy)
+ ltgr %r4,%r4
+ jz .Lmemcpy_exit
+ aghi %r4,-1
+ srlg %r5,%r4,8
+ ltgr %r5,%r5
+ lgr %r1,%r2
+ jnz .Lmemcpy_loop
+.Lmemcpy_remainder:
+ larl %r5,.Lmemcpy_mvc
+ ex %r4,0(%r5)
+.Lmemcpy_exit:
+ BR_EX %r14
+.Lmemcpy_loop:
+ mvc 0(256,%r1),0(%r3)
+ la %r1,256(%r1)
+ la %r3,256(%r3)
+ brctg %r5,.Lmemcpy_loop
+ j .Lmemcpy_remainder
+.Lmemcpy_mvc:
+ mvc 0(1,%r1),0(%r3)
+EXPORT_SYMBOL(memcpy)
+
+/*
+ * __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
+ENTRY(__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)
+ larl %r5,.L__memset_mvc\bits
+ ex %r4,0(%r5)
+ 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)
+.endm
+
+__MEMSET 16,2,sth
+EXPORT_SYMBOL(__memset16)
+
+__MEMSET 32,4,st
+EXPORT_SYMBOL(__memset32)
+
+__MEMSET 64,8,stg
+EXPORT_SYMBOL(__memset64)