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/bionic/setjmp.S b/libc/arch-aarch64/bionic/setjmp.S
new file mode 100644
index 0000000..faa854f
--- /dev/null
+++ b/libc/arch-aarch64/bionic/setjmp.S
@@ -0,0 +1,123 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ * All rights reserved
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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
+ * COPYRIGHT OWNER 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.
+ */
+
+#include <machine/asm.h>
+#include <machine/setjmp.h>
+
+/*
+ * C library - _setjmp, _longjmp
+ *
+ * _longjmp(jmp_buf state, int value)
+ * will generate a "return(v)" from the last call to _setjmp(state) by restoring
+ * registers from the stack. The previous signal state is NOT restored.
+ *
+ * NOTE: x0 return value
+ *       x9-x15 temporary registers
+ */
+
+ENTRY(setjmp)
+    /* block all signals an retrieve signal mask */
+    stp     x0, x30, [sp, #-16]!
+
+    mov     x0, xzr
+    bl      PIC_SYM(_C_LABEL(sigblock), PLT)
+    mov     w1, w0
+
+    ldp     x0, x30, [sp], #16
+
+    /* store signal mask */
+    str     w1, [x0, #(_JB_SIGMASK *4)]
+
+    /* store magic number */
+    ldr     w9, .L_setjmp_magic
+    str     w9, [x0, #(_JB_MAGIC * 4)]
+
+    /* store core registers */
+    mov     x10, sp
+    stp     x30, x10, [x0, #(_JB_CORE_BASE * 4 + 16 * 0)]
+    stp     x28, x29, [x0, #(_JB_CORE_BASE * 4 + 16 * 1)]
+    stp     x26, x27, [x0, #(_JB_CORE_BASE * 4 + 16 * 2)]
+    stp     x24, x25, [x0, #(_JB_CORE_BASE * 4 + 16 * 3)]
+    stp     x22, x23, [x0, #(_JB_CORE_BASE * 4 + 16 * 4)]
+    stp     x20, x21, [x0, #(_JB_CORE_BASE * 4 + 16 * 5)]
+    str     x19,      [x0, #(_JB_CORE_BASE * 4 + 16 * 6)]
+
+    /* store floating point registers */
+    stp     d14, d15, [x0, #(_JB_FLOAT_BASE * 4 + 16 * 0)]
+    stp     d12, d13, [x0, #(_JB_FLOAT_BASE * 4 + 16 * 1)]
+    stp     d10, d11, [x0, #(_JB_FLOAT_BASE * 4 + 16 * 2)]
+    stp     d8,  d9,  [x0, #(_JB_FLOAT_BASE * 4 + 16 * 3)]
+
+    mov     w0, wzr
+    ret
+END(setjmp)
+
+.L_setjmp_magic:
+    .word   _JB_MAGIC__SETJMP
+
+ENTRY(longjmp)
+    /* check magic */
+    ldr     w9, .L_setjmp_magic
+    ldr     w10, [x0, #(_JB_MAGIC * 4)]
+    cmp     w9, w10
+    b.ne    botch
+
+    /* restore core registers */
+    ldp     x30, x10, [x0, #(_JB_CORE_BASE * 4 + 16 * 0)]
+    mov     sp, x10
+    ldp     x28, x29, [x0, #(_JB_CORE_BASE * 4 + 16 * 1)]
+    ldp     x26, x27, [x0, #(_JB_CORE_BASE * 4 + 16 * 2)]
+    ldp     x24, x25, [x0, #(_JB_CORE_BASE * 4 + 16 * 3)]
+    ldp     x22, x23, [x0, #(_JB_CORE_BASE * 4 + 16 * 4)]
+    ldp     x20, x21, [x0, #(_JB_CORE_BASE * 4 + 16 * 5)]
+    ldr     x19,      [x0, #(_JB_CORE_BASE * 4 + 16 * 6)]
+
+    /* restore floating point registers */
+    ldp     d14, d15, [x0, #(_JB_FLOAT_BASE * 4 + 16 * 0)]
+    ldp     d12, d13, [x0, #(_JB_FLOAT_BASE * 4 + 16 * 1)]
+    ldp     d10, d11, [x0, #(_JB_FLOAT_BASE * 4 + 16 * 2)]
+    ldp     d8,  d9,  [x0, #(_JB_FLOAT_BASE * 4 + 16 * 3)]
+
+    /* validate sp (sp mod 16 = 0) and lr (lr mod 4 = 0) */
+    tst     x30, #3
+    b.ne    botch
+    mov     x10, sp
+    tst     x10, #15
+    b.ne    botch
+
+    /* set return value */
+    cmp     w1, wzr
+    csinc   w0, w1, wzr, ne
+    ret
+
+    /* validation failed, die die die */
+botch:
+    bl      PIC_SYM(_C_LABEL(longjmperror), PLT)
+    bl      PIC_SYM(_C_LABEL(abort), PLT)
+    b       . - 8       /* Cannot get here */
+END(longjmp)