xen: xensyms support

Export Xen symbols to dom0 via /proc/xen/xensyms (similar to
/proc/kallsyms).

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>

drivers/xen/Kconfig

@@ -280,4 +280,12 @@ config XEN_ACPI
 	def_bool y
 	depends on X86 && ACPI
 
+config XEN_SYMS
+       bool "Xen symbols"
+       depends on X86 && XEN_DOM0 && XENFS
+       default y if KALLSYMS
+       help
+          Exports hypervisor symbols (along with their types and addresses) via
+          /proc/xen/xensyms file, similar to /proc/kallsyms
+
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