scripts/gdb: add internal helper and convenience function for per-cpu lookup

This function allows to obtain a per-cpu variable, either of the current
or an explicitly specified CPU.

Note: sparc64 version is untested.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Ben Widawsky <ben@bwidawsk.net>
Cc: Borislav Petkov <bp@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/scripts/gdb/vmlinux-gdb.py b/scripts/gdb/vmlinux-gdb.py
index 4d7eb2c..4848928 100644
--- a/scripts/gdb/vmlinux-gdb.py
+++ b/scripts/gdb/vmlinux-gdb.py
@@ -27,3 +27,4 @@
     import linux.modules
     import linux.dmesg
     import linux.tasks
+    import linux.cpus