AArch64: Add initial support for AArch64

This is the first patch out of a series of patches that add support for
AArch64, the new 64bit execution state of the ARMv8 Architecture. The
patches add support for LP64 programming model.

The patch adds:
* "arch-aarch64" to the architecture directories.
* "arch-aarch64/include" - headers used by libc
* "arch-aarch64/bionic":
    - crtbegin, crtend support;
    - aarch64 specific syscall stubs;
    - setjmp, clone, vfork assembly files.

Change-Id: If72b859f81928d03ad05d4ccfcb54c2f5dbf99a5
Signed-off-by: Serban Constantinescu <serban.constantinescu@arm.com>
diff --git a/libc/arch-aarch64/include/machine/asm.h b/libc/arch-aarch64/include/machine/asm.h
new file mode 100644
index 0000000..3f8b908
--- /dev/null
+++ b/libc/arch-aarch64/include/machine/asm.h
@@ -0,0 +1,128 @@
+/*	$OpenBSD: asm.h,v 1.1 2004/02/01 05:09:49 drahn Exp $	*/
+/*	$NetBSD: asm.h,v 1.4 2001/07/16 05:43:32 matt Exp $	*/
+
+/*
+ * Copyright (c) 1990 The Regents of the University of California.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * William Jolitz.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	from: @(#)asm.h	5.5 (Berkeley) 5/7/91
+ */
+
+#ifndef _AARCH64_ASM_H_
+#define _AARCH64_ASM_H_
+
+/* TODO: Add cfi directives for creating/restoring FP */
+#ifdef __ELF__
+# define	_C_LABEL(x)	x
+#else
+# ifdef __STDC__
+#  define	_C_LABEL(x)	_ ## x
+# else
+#  define	_C_LABEL(x)	_/**/x
+# endif
+#endif
+#define	_ASM_LABEL(x)	x
+
+#ifdef __STDC__
+# define	__CONCAT(x,y)	x ## y
+# define	__STRING(x)	#x
+#else
+# define	__CONCAT(x,y)	x/**/y
+# define	__STRING(x)	"x"
+#endif
+
+#ifndef _ALIGN_TEXT
+# define	_ALIGN_TEXT	.align 0
+#endif
+
+#define	_ASM_TYPE_FUNCTION	%function
+#define	_ASM_TYPE_OBJECT	%object
+#define	_ENTRY(x) \
+	.text; _ALIGN_TEXT; .globl x; .type x,_ASM_TYPE_FUNCTION; x: .cfi_startproc
+
+#define	_ASM_SIZE(x)	.size x, .-x;
+
+#define _END(x) \
+	.cfi_endproc; \
+	_ASM_SIZE(x)
+
+#define	ENTRY(y)	_ENTRY(_C_LABEL(y));
+#define	ENTRY_NP(y)	_ENTRY(_C_LABEL(y))
+#define	END(y)		_END(_C_LABEL(y))
+#define	ASENTRY(y)	_ENTRY(_ASM_LABEL(y)); _PROF_PROLOGUE
+#define	ASENTRY_NP(y)	_ENTRY(_ASM_LABEL(y))
+#define	ASEND(y)	_END(_ASM_LABEL(y))
+
+#ifdef __ELF__
+#define	ENTRY_PRIVATE(y)  ENTRY(y); .hidden _C_LABEL(y)
+#else
+#define	ENTRY_PRIVATE(y)  ENTRY(y)
+#endif
+
+#define	ASMSTR		.asciz
+
+#if defined(__ELF__) && defined(PIC)
+#ifdef __STDC__
+#define	PIC_SYM(x,y)	x ## ( ## y ## )
+#else
+#define	PIC_SYM(x,y)	x/**/(/**/y/**/)
+#endif
+#else
+#define	PIC_SYM(x,y)	x
+#endif
+
+#ifdef __ELF__
+#define	RCSID(x)	.section ".ident"; .asciz x
+#else
+#define	RCSID(x)	.text; .asciz x
+#endif
+
+#ifdef __ELF__
+#define	WEAK_ALIAS(alias,sym)						\
+	.weak alias;							\
+	alias = sym
+#endif
+
+#ifdef __STDC__
+#define	WARN_REFERENCES(sym,msg)					\
+	.stabs msg ## ,30,0,0,0 ;					\
+	.stabs __STRING(_C_LABEL(sym)) ## ,1,0,0,0
+#elif defined(__ELF__)
+#define	WARN_REFERENCES(sym,msg)					\
+	.stabs msg,30,0,0,0 ;						\
+	.stabs __STRING(sym),1,0,0,0
+#else
+#define	WARN_REFERENCES(sym,msg)					\
+	.stabs msg,30,0,0,0 ;						\
+	.stabs __STRING(_/**/sym),1,0,0,0
+#endif /* __STDC__ */
+
+#endif /* _AARCH64_ASM_H_ */
+