[ARM] 5383/2: unwind: Add core support for ARM stack unwinding

This patch adds the main functionality for parsing the stack unwinding
information generated by the ARM EABI toolchains. The unwinding
information consists of an index with a pair of words per function and a
table with unwinding instructions. For more information, see "Exception
Handling ABI for the ARM Architecture" at:

http://infocenter.arm.com/help/topic/com.arm.doc.subset.swdev.abi/index.html

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/kernel/vmlinux.lds.S b/arch/arm/kernel/vmlinux.lds.S
index 0021607..5f66459 100644
--- a/arch/arm/kernel/vmlinux.lds.S
+++ b/arch/arm/kernel/vmlinux.lds.S
@@ -80,6 +80,8 @@
 		EXIT_TEXT
 		EXIT_DATA
 		*(.exitcall.exit)
+		*(.ARM.exidx.exit.text)
+		*(.ARM.extab.exit.text)
 #ifndef CONFIG_MMU
 		*(.fixup)
 		*(__ex_table)
@@ -110,6 +112,23 @@
 
 	_etext = .;			/* End of text and rodata section */
 
+#ifdef CONFIG_ARM_UNWIND
+	/*
+	 * Stack unwinding tables
+	 */
+	. = ALIGN(8);
+	.ARM.unwind_idx : {
+		__start_unwind_idx = .;
+		*(.ARM.exidx*)
+		__stop_unwind_idx = .;
+	}
+	.ARM.unwind_tab : {
+		__start_unwind_tab = .;
+		*(.ARM.extab*)
+		__stop_unwind_tab = .;
+	}
+#endif
+
 #ifdef CONFIG_XIP_KERNEL
 	__data_loc = ALIGN(4);		/* location in binary */
 	. = PAGE_OFFSET + TEXT_OFFSET;