arm64: klib: Optimised memory functions

This patch introduces AArch64-specific memory functions (memcpy,
memmove, memchr, memset). These functions are not optimised for any CPU
implementation but can be used as a starting point once hardware is
available.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arch/arm64/include/asm/Kbuild

@@ -39,7 +39,6 @@ generic-y += shmbuf.h
 generic-y += sizes.h
 generic-y += socket.h
 generic-y += sockios.h
-generic-y += string.h
 generic-y += switch_to.h
 generic-y += swab.h
 generic-y += termbits.h

arch/arm64/include/asm/string.h

+/*
+ * Copyright (C) 2013 ARM Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef __ASM_STRING_H
+#define __ASM_STRING_H
+
+#define __HAVE_ARCH_MEMCPY
+extern void *memcpy(void *, const void *, __kernel_size_t);
+
+#define __HAVE_ARCH_MEMMOVE
+extern void *memmove(void *, const void *, __kernel_size_t);
+
+#define __HAVE_ARCH_MEMCHR
+extern void *memchr(const void *, int, __kernel_size_t);
+
+#define __HAVE_ARCH_MEMSET
+extern void *memset(void *, int, __kernel_size_t);
+
+#endif

arch/arm64/kernel/arm64ksyms.c

@@ -46,3 +46,9 @@ EXPORT_SYMBOL(__atomic_hash);
 
 	/* physical memory */
 EXPORT_SYMBOL(memstart_addr);
+
+	/* string / mem functions */
+EXPORT_SYMBOL(memset);
+EXPORT_SYMBOL(memcpy);
+EXPORT_SYMBOL(memmove);
+EXPORT_SYMBOL(memchr);

arch/arm64/lib/Makefile

 lib-y		:= bitops.o delay.o					\
 		   strncpy_from_user.o strnlen_user.o clear_user.o	\
 		   copy_from_user.o copy_to_user.o copy_in_user.o	\
-		   copy_page.o clear_page.o
+		   copy_page.o clear_page.o				\
+		   memchr.o memcpy.o memmove.o memset.o

arch/arm64/lib/memchr.S

+/*
+ * Based on arch/arm/lib/memchr.S
+ *
+ * Copyright (C) 1995-2000 Russell King
+ * Copyright (C) 2013 ARM Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+
+/*
+ * Find a character in an area of memory.
+ *
+ * Parameters:
+ *	x0 - buf
+ *	x1 - c
+ *	x2 - n
+ * Returns:
+ *	x0 - address of first occurrence of 'c' or 0
+ */
+ENTRY(memchr)
+	and	w1, w1, #0xff
+1:	subs	x2, x2, #1
+	b.mi	2f
+	ldrb	w3, [x0], #1
+	cmp	w3, w1
+	b.ne	1b
+	sub	x0, x0, #1
+	ret
+2:	mov	x0, #0
+	ret
+ENDPROC(memchr)

arch/arm64/lib/memcpy.S

+/*
+ * Copyright (C) 2013 ARM Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+
+/*
+ * Copy a buffer from src to dest (alignment handled by the hardware)
+ *
+ * Parameters:
+ *	x0 - dest
+ *	x1 - src
+ *	x2 - n
+ * Returns:
+ *	x0 - dest
+ */
+ENTRY(memcpy)
+	mov	x4, x0
+	subs	x2, x2, #8
+	b.mi	2f
+1:	ldr	x3, [x1], #8
+	subs	x2, x2, #8
+	str	x3, [x4], #8
+	b.pl	1b
+2:	adds	x2, x2, #4
+	b.mi	3f
+	ldr	w3, [x1], #4
+	sub	x2, x2, #4
+	str	w3, [x4], #4
+3:	adds	x2, x2, #2
+	b.mi	4f
+	ldrh	w3, [x1], #2
+	sub	x2, x2, #2
+	strh	w3, [x4], #2
+4:	adds	x2, x2, #1
+	b.mi	5f
+	ldrb	w3, [x1]
+	strb	w3, [x4]
+5:	ret
+ENDPROC(memcpy)

arch/arm64/lib/memmove.S

+/*
+ * Copyright (C) 2013 ARM Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+
+/*
+ * Move a buffer from src to test (alignment handled by the hardware).
+ * If dest <= src, call memcpy, otherwise copy in reverse order.
+ *
+ * Parameters:
+ *	x0 - dest
+ *	x1 - src
+ *	x2 - n
+ * Returns:
+ *	x0 - dest
+ */
+ENTRY(memmove)
+	cmp	x0, x1
+	b.ls	memcpy
+	add	x4, x0, x2
+	add	x1, x1, x2
+	subs	x2, x2, #8
+	b.mi	2f
+1:	ldr	x3, [x1, #-8]!
+	subs	x2, x2, #8
+	str	x3, [x4, #-8]!
+	b.pl	1b
+2:	adds	x2, x2, #4
+	b.mi	3f
+	ldr	w3, [x1, #-4]!
+	sub	x2, x2, #4
+	str	w3, [x4, #-4]!
+3:	adds	x2, x2, #2
+	b.mi	4f
+	ldrh	w3, [x1, #-2]!
+	sub	x2, x2, #2
+	strh	w3, [x4, #-2]!
+4:	adds	x2, x2, #1
+	b.mi	5f
+	ldrb	w3, [x1, #-1]
+	strb	w3, [x4, #-1]
+5:	ret
+ENDPROC(memmove)

arch/arm64/lib/memset.S

+/*
+ * Copyright (C) 2013 ARM Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+
+/*
+ * Fill in the buffer with character c (alignment handled by the hardware)
+ *
+ * Parameters:
+ *	x0 - buf
+ *	x1 - c
+ *	x2 - n
+ * Returns:
+ *	x0 - buf
+ */
+ENTRY(memset)
+	mov	x4, x0
+	and	w1, w1, #0xff
+	orr	w1, w1, w1, lsl #8
+	orr	w1, w1, w1, lsl #16
+	orr	x1, x1, x1, lsl #32
+	subs	x2, x2, #8
+	b.mi	2f
+1:	str	x1, [x4], #8
+	subs	x2, x2, #8
+	b.pl	1b
+2:	adds	x2, x2, #4
+	b.mi	3f
+	sub	x2, x2, #4
+	str	w1, [x4], #4
+3:	adds	x2, x2, #2
+	b.mi	4f
+	sub	x2, x2, #2
+	strh	w1, [x4], #2
+4:	adds	x2, x2, #1
+	b.mi	5f
+	strb	w1, [x4]
+5:	ret
+ENDPROC(memset)