1 files changed, 184 insertions, 0 deletions
diff --git a/arch/s390/lib/mem.S b/arch/s390/lib/mem.S
new file mode 100644
index 000000000..40c4d59c9
--- /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)