Per-cpu data cache restructuring

This patch prepares the per-cpu pointer cache for wider use by:
* renaming the structure to cpu_data and placing in new header
* providing accessors for this CPU, or other CPUs
* splitting the initialization of the TPIDR pointer from the
  initialization of the cpu_data content
* moving the crash stack initialization to a crash stack function
* setting the TPIDR pointer very early during boot

Change-Id: Icef9004ff88f8eb241d48c14be3158087d7e49a3
diff --git a/bl31/aarch64/cpu_data.S b/bl31/aarch64/cpu_data.S
new file mode 100644
index 0000000..feb51d6
--- /dev/null
+++ b/bl31/aarch64/cpu_data.S
@@ -0,0 +1,85 @@
+/*
+ * Copyright (c) 2014, ARM Limited and Contributors. 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.
+ *
+ * Neither the name of ARM 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 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 HOLDER 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 <asm_macros.S>
+#include <cpu_data.h>
+
+.globl	init_cpu_data_ptr
+.globl	_cpu_data_by_mpidr
+.globl	_cpu_data_by_index
+
+/* -----------------------------------------------------------------
+ * void init_cpu_data_ptr(void)
+ *
+ * Initialise the TPIDR_EL3 register to refer to the cpu_data_t
+ * for the calling CPU. This must be called before cm_get_cpu_data()
+ *
+ * This can be called without a valid stack.
+ * clobbers: x0, x1, x9, x10
+ * -----------------------------------------------------------------
+ */
+func init_cpu_data_ptr
+	mov	x10, x30
+	mrs	x0, mpidr_el1
+	bl	_cpu_data_by_mpidr
+	msr	tpidr_el3, x0
+	ret	x10
+
+
+/* -----------------------------------------------------------------
+ * cpu_data_t *_cpu_data_by_mpidr(uint64_t mpidr)
+ *
+ * Return the cpu_data structure for the CPU with given MPIDR
+ *
+ * This can be called without a valid stack. It assumes that
+ * platform_get_core_pos() does not clobber register x9.
+ * clobbers: x0, x1, x9
+ * -----------------------------------------------------------------
+ */
+func _cpu_data_by_mpidr
+	mov	x9, x30
+	bl	platform_get_core_pos
+	mov	x30, x9
+	b	_cpu_data_by_index
+
+
+/* -----------------------------------------------------------------
+ * cpu_data_t *_cpu_data_by_index(uint32_t cpu_index)
+ *
+ * Return the cpu_data structure for the CPU with given linear index
+ *
+ * This can be called without a valid stack.
+ * clobbers: x0, x1
+ * -----------------------------------------------------------------
+ */
+func _cpu_data_by_index
+	adr	x1, percpu_data
+	add	x0, x1, x0, LSL #CPU_DATA_LOG2SIZE
+	ret