Relocate AArch64 from ports to libc.

This patch moves the AArch64 port to the main sysdeps hierarchy.  The
move is essentially:

  git mv ports/sysdeps/aarch64 sysdeps/aarch64
  git mv ports/sysdeps/unix/sysv/linux/aarch64 sysdeps/unix/sysv/linux/aarch64

The README is updated and I've updated ChangeLog.aarch64 along the
lines of the ARM move.  The AArch64 build has been tested to confirm
that there were no changes in objdump -dr output or the shared
objects.

1 files changed, 93 insertions, 0 deletions

diff --git a/sysdeps/aarch64/start.S b/sysdeps/aarch64/start.S
new file mode 100644
index 0000000000..35d603ae9e
--- /dev/null
+++ b/sysdeps/aarch64/start.S
@@ -0,0 +1,93 @@
+/* Copyright (C) 1995-2014 Free Software Foundation, Inc.
+
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public License as
+   published by the Free Software Foundation; either version 2.1 of the
+   License, or (at your option) any later version.
+
+   The GNU C Library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library.  If not, see
+   <http://www.gnu.org/licenses/>.  */
+
+/* This is the canonical entry point, usually the first thing in the text
+   segment.
+
+   Note that the code in the .init section has already been run.
+   This includes _init and _libc_init
+
+
+   At this entry point, most registers' values are unspecified, except:
+
+   x0		Contains a function pointer to be registered with `atexit'.
+		This is how the dynamic linker arranges to have DT_FINI
+		functions called for shared libraries that have been loaded
+		before this code runs.
+
+   sp		The stack contains the arguments and environment:
+		0(sp)			argc
+		8(sp)			argv[0]
+		...
+		(8*argc)(sp)		NULL
+		(8*(argc+1))(sp)	envp[0]
+		...
+					NULL
+ */
+
+	.text
+	.globl _start
+	.type _start,#function
+_start:
+	/* Create an initial frame with 0 LR and FP */
+	mov	x29, #0
+	mov	x30, #0
+	mov	x29, sp
+
+	/* Setup rtld_fini in argument register */
+	mov	x5, x0
+
+	/* Load argc and a pointer to argv */
+	ldr	x1, [sp, #0]
+	add	x2, sp, #8
+
+	/* Setup stack limit in argument register */
+	mov	x6, sp
+
+#ifdef SHARED
+        adrp    x0, :got:main
+	ldr     x0, [x0, #:got_lo12:main]
+
+        adrp    x3, :got:__libc_csu_init
+	ldr     x3, [x3, #:got_lo12:__libc_csu_init]
+
+        adrp    x4, :got:__libc_csu_fini
+	ldr     x4, [x4, #:got_lo12:__libc_csu_fini]
+#else
+	/* Set up the other arguments in registers */
+	ldr	x0, =main
+	ldr	x3, =__libc_csu_init
+	ldr	x4, =__libc_csu_fini
+#endif
+
+	/* __libc_start_main (main, argc, argv, init, fini, rtld_fini,
+			      stack_end) */
+
+	/* Let the libc call main and exit with its return code.  */
+	bl	__libc_start_main
+
+	/* should never get here....*/
+	bl	abort
+
+	/* Define a symbol for the first piece of initialized data.  */
+	.data
+	.globl __data_start
+__data_start:
+	.long 0
+	.weak data_start
+	data_start = __data_start