arm64: Build infrastructure

This patch adds Makefile and Kconfig files required for building an
AArch64 kernel.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Olof Johansson <olof@lixom.net>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>

arch/arm64/kernel/.gitignore

@@ -0,0 +1 @@
+vmlinux.lds

arch/arm64/kernel/Makefile

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+#
+# Makefile for the linux kernel.
+#
+
+CPPFLAGS_vmlinux.lds	:= -DTEXT_OFFSET=$(TEXT_OFFSET)
+AFLAGS_head.o		:= -DTEXT_OFFSET=$(TEXT_OFFSET)
+
+# Object file lists.
+arm64-obj-y		:= cputable.o debug-monitors.o entry.o irq.o fpsimd.o	\
+			   entry-fpsimd.o process.o ptrace.o setup.o signal.o	\
+			   sys.o stacktrace.o time.o traps.o io.o vdso.o
+
+arm64-obj-$(CONFIG_COMPAT)		+= sys32.o kuser32.o signal32.o 	\
+					   sys_compat.o
+arm64-obj-$(CONFIG_MODULES)		+= arm64ksyms.o module.o
+arm64-obj-$(CONFIG_SMP)			+= smp.o
+arm64-obj-$(CONFIG_HW_PERF_EVENTS)	+= perf_event.o
+arm64-obj-$(CONFIG_HAVE_HW_BREAKPOINT)+= hw_breakpoint.o
+
+obj-y					+= $(arm64-obj-y) vdso/
+obj-m					+= $(arm64-obj-m)
+head-y					:= head.o
+extra-y					:= $(head-y) vmlinux.lds
+
+# vDSO - this must be built first to generate the symbol offsets
+$(call objectify,$(arm64-obj-y)): $(obj)/vdso/vdso-offsets.h
+$(obj)/vdso/vdso-offsets.h: $(obj)/vdso

arch/arm64/kernel/vmlinux.lds.S

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+/*
+ * ld script to make ARM Linux kernel
+ * taken from the i386 version by Russell King
+ * Written by Martin Mares <mj@atrey.karlin.mff.cuni.cz>
+ */
+
+#include <asm-generic/vmlinux.lds.h>
+#include <asm/thread_info.h>
+#include <asm/memory.h>
+#include <asm/page.h>
+
+#define ARM_EXIT_KEEP(x)
+#define ARM_EXIT_DISCARD(x)	x
+
+OUTPUT_ARCH(aarch64)
+ENTRY(stext)
+
+jiffies = jiffies_64;
+
+SECTIONS
+{
+	/*
+	 * XXX: The linker does not define how output sections are
+	 * assigned to input sections when there are multiple statements
+	 * matching the same input section name.  There is no documented
+	 * order of matching.
+	 */
+	/DISCARD/ : {
+		ARM_EXIT_DISCARD(EXIT_TEXT)
+		ARM_EXIT_DISCARD(EXIT_DATA)
+		EXIT_CALL
+		*(.discard)
+		*(.discard.*)
+	}
+
+	. = PAGE_OFFSET + TEXT_OFFSET;
+
+	.head.text : {
+		_text = .;
+		HEAD_TEXT
+	}
+	.text : {			/* Real text segment		*/
+		_stext = .;		/* Text and read-only data	*/
+			*(.smp.pen.text)
+			__exception_text_start = .;
+			*(.exception.text)
+			__exception_text_end = .;
+			IRQENTRY_TEXT
+			TEXT_TEXT
+			SCHED_TEXT
+			LOCK_TEXT
+			*(.fixup)
+			*(.gnu.warning)
+		. = ALIGN(16);
+		*(.got)			/* Global offset table		*/
+	}
+
+	RO_DATA(PAGE_SIZE)
+
+	_etext = .;			/* End of text and rodata section */
+
+	. = ALIGN(PAGE_SIZE);
+	__init_begin = .;
+
+	INIT_TEXT_SECTION(8)
+	.exit.text : {
+		ARM_EXIT_KEEP(EXIT_TEXT)
+	}
+	. = ALIGN(16);
+	.init.data : {
+		INIT_DATA
+		INIT_SETUP(16)
+		INIT_CALLS
+		CON_INITCALL
+		SECURITY_INITCALL
+		INIT_RAM_FS
+	}
+	.exit.data : {
+		ARM_EXIT_KEEP(EXIT_DATA)
+	}
+
+	PERCPU_SECTION(64)
+
+	__init_end = .;
+	. = ALIGN(THREAD_SIZE);
+	__data_loc = .;
+
+	.data : AT(__data_loc) {
+		_data = .;		/* address in memory */
+		_sdata = .;
+
+		/*
+		 * first, the init task union, aligned
+		 * to an 8192 byte boundary.
+		 */
+		INIT_TASK_DATA(THREAD_SIZE)
+		NOSAVE_DATA
+		CACHELINE_ALIGNED_DATA(64)
+		READ_MOSTLY_DATA(64)
+
+		/*
+		 * The exception fixup table (might need resorting at runtime)
+		 */
+		. = ALIGN(32);
+		__start___ex_table = .;
+		*(__ex_table)
+		__stop___ex_table = .;
+
+		/*
+		 * and the usual data section
+		 */
+		DATA_DATA
+		CONSTRUCTORS
+
+		_edata = .;
+	}
+	_edata_loc = __data_loc + SIZEOF(.data);
+
+	NOTES
+
+	BSS_SECTION(0, 0, 0)
+	_end = .;
+
+	STABS_DEBUG
+	.comment 0 : { *(.comment) }
+}