s390/decompressor: reuse lib/mem.S for mem functions

Reusing arch/s390/lib/mem.S file solves a problem that sclp_early_core.c
and its dependencies have to be compiled with -march=z900 (no need to
compile compressed/misc.c with -march=z900). This also allows to avoid
mem functions duplicates, makes code a bit smaller and optimized mem
functions are utilized.
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/boot/Makefile

@@ -17,6 +17,8 @@ KBUILD_CFLAGS := $(KBUILD_CFLAGS_DECOMPRESSOR)
 ifneq ($(CC_FLAGS_MARCH),-march=z900)
 AFLAGS_REMOVE_head.o		+= $(CC_FLAGS_MARCH)
 AFLAGS_head.o			+= -march=z900
+AFLAGS_REMOVE_mem.o		+= $(CC_FLAGS_MARCH)
+AFLAGS_mem.o			+= -march=z900
 CFLAGS_REMOVE_als.o		+= $(CC_FLAGS_MARCH)
 CFLAGS_als.o			+= -march=z900
 CFLAGS_REMOVE_sclp_early_core.o	+= $(CC_FLAGS_MARCH)
@@ -25,7 +27,7 @@ endif
 
 CFLAGS_sclp_early_core.o += -I$(srctree)/drivers/s390/char
 
-obj-y	:= head.o als.o ebcdic.o sclp_early_core.o
+obj-y	:= head.o als.o ebcdic.o sclp_early_core.o mem.o
 targets	:= bzImage setup.a $(obj-y)
 subdir-	:= compressed
 

arch/s390/boot/compressed/misc.c

@@ -71,43 +71,6 @@ static int puts(const char *s)
 	return 0;
 }
 
-void *memset(void *s, int c, size_t n)
-{
-	char *xs;
-
-	xs = s;
-	while (n--)
-		*xs++ = c;
-	return s;
-}
-
-void *memcpy(void *dest, const void *src, size_t n)
-{
-	const char *s = src;
-	char *d = dest;
-
-	while (n--)
-		*d++ = *s++;
-	return dest;
-}
-
-void *memmove(void *dest, const void *src, size_t n)
-{
-	const char *s = src;
-	char *d = dest;
-
-	if (d <= s) {
-		while (n--)
-			*d++ = *s++;
-	} else {
-		d += n;
-		s += n;
-		while (n--)
-			*--d = *--s;
-	}
-	return dest;
-}
-
 static void error(char *x)
 {
 	unsigned long long psw = 0x000a0000deadbeefULL;

arch/s390/boot/mem.S

+/* SPDX-License-Identifier: GPL-2.0 */
+#include "../lib/mem.S"