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, 100 insertions, 0 deletions

diff --git a/sysdeps/unix/sysv/linux/aarch64/swapcontext.S b/sysdeps/unix/sysv/linux/aarch64/swapcontext.S
new file mode 100644
index 0000000000..deb27fa46c
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/aarch64/swapcontext.S
@@ -0,0 +1,100 @@
+/* Modify saved context.
+
+   Copyright (C) 2009-2014 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/>.  */
+
+#include <sysdep.h>
+
+#include "ucontext_i.h"
+#include "ucontext-internal.h"
+
+/* int swapcontext (ucontext_t *oucp, const ucontext_t *ucp) */
+
+	.text
+ENTRY(__swapcontext)
+	/* Set the value returned when swapcontext() returns in this context. */
+	str	xzr,      [x0, oX0 +  0 * SZREG]
+
+	stp	x18, x19, [x0, oX0 + 18 * SZREG]
+	stp	x20, x21, [x0, oX0 + 20 * SZREG]
+	stp	x22, x23, [x0, oX0 + 22 * SZREG]
+	stp	x24, x25, [x0, oX0 + 24 * SZREG]
+	stp	x26, x27, [x0, oX0 + 26 * SZREG]
+	stp	x28, x29, [x0, oX0 + 28 * SZREG]
+	str     x30,      [x0, oX0 + 30 * SZREG]
+	str     x30,      [x0, oPC]
+	mov	x2, sp
+	str     x2,       [x0, oSP]
+
+	/* Figure out where to place the first context extension
+	   block.  */
+	add     x2, x0, #oEXTENSION
+
+	/* Write the context extension fpsimd header.  */
+	mov	w3, #(FPSIMD_MAGIC & 0xffff)
+	movk	w3, #(FPSIMD_MAGIC >> 16), lsl #16
+	str	w3, [x2, #oHEAD + oMAGIC]
+	mov	w3, #FPSIMD_CONTEXT_SIZE
+	str	w3, [x2, #oHEAD + oSIZE]
+
+	/* Fill in the FP SIMD context.  */
+	add	x3, x2, #oV0 + 8 * SZVREG
+	stp	 d8,  d9, [x3], #2 * SZVREG
+	stp	d10, d11, [x3], #2 * SZVREG
+	stp	d12, d13, [x3], #2 * SZVREG
+	stp	d14, d15, [x3], #2 * SZVREG
+
+	add	x3, x2, #oFPSR
+
+	mrs	x4, fpsr
+	str	w4, [x3, #oFPSR - oFPSR]
+
+	mrs	x4, fpcr
+	str	w4, [x3, #oFPCR - oFPSR]
+
+	/* Write the termination context extension header.  */
+	add	x2, x2, #FPSIMD_CONTEXT_SIZE
+
+	str	xzr, [x2, #oHEAD + oMAGIC]
+	str	xzr, [x2, #oHEAD + oSIZE]
+
+	/* Preserve ucp.  */
+	mov	x21, x1
+
+	/* rt_sigprocmask (SIG_SETMASK, &ucp->uc_sigmask, &oucp->uc_sigmask,
+			   _NSIG8) */
+	/* Grab the signal mask */
+	/* rt_sigprocmask (SIG_BLOCK, NULL, &ucp->uc_sigmask, _NSIG8) */
+	add	x2, x0, #UCONTEXT_SIGMASK
+	mov	x0, SIG_BLOCK
+	mov	x1, 0
+	mov	x3, _NSIG8
+	mov	x8, SYS_ify (rt_sigprocmask)
+	svc	0
+	cbnz	x0, 1f
+
+	mov     x22, x30
+	mov	x0, x21
+	bl	JUMPTARGET (__setcontext)
+	mov     x30, x22
+	RET
+
+1:
+	b	C_SYMBOL_NAME(__syscall_error)
+PSEUDO_END (__swapcontext)
+weak_alias (__swapcontext, swapcontext)