perf report: Deal with maps

In order to deal with [vdso] maps generalize the ip->symbol path
a bit and allow to override some bits with custom functions.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/Documentation/perf_counter/util/symbol.c b/Documentation/perf_counter/util/symbol.c
index 15d5cf9..a06bbfba 100644
--- a/Documentation/perf_counter/util/symbol.c
+++ b/Documentation/perf_counter/util/symbol.c
@@ -45,6 +45,7 @@
 		strcpy(self->name, name);
 		self->syms = RB_ROOT;
 		self->sym_priv_size = sym_priv_size;
+		self->find_symbol = dso__find_symbol;
 	}
 
 	return self;