perf tools: /proc/modules names don't always match its name

$ cut -d' ' -f1 /proc/modules|grep _|wc -l
 29
 $ cut -d' ' -f1 /proc/modules|grep _|sed 's/$/.ko'/g|while read n;do find /lib/modules/`uname -r` -name $n;done|wc -l
 12

For instance:

 $ grep ^aes_x86 /proc/modules
 aes_x86_64 9056 2 - Live 0xffffffffa0091000
 $ l /lib/modules/2.6.31-tip/kernel/arch/x86/crypto/aes-x86_64.ko
 -rw-r--r-- 1 root root 136438 2009-09-22 19:05 /lib/modules/2.6.31-tip/kernel/arch/x86/crypto/aes-x86_64.ko

Handle that by introducing a strxfrchar routine that replaces
dashes with underscores when matching file names to loaded modules.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/tools/perf/util/string.c b/tools/perf/util/string.c
index c93eca9..04743d3 100644
--- a/tools/perf/util/string.c
+++ b/tools/perf/util/string.c
@@ -1,3 +1,4 @@
+#include <string.h>
 #include "string.h"
 
 static int hex(char ch)
@@ -32,3 +33,13 @@
 
 	return p - ptr;
 }
+
+char *strxfrchar(char *s, char from, char to)
+{
+	char *p = s;
+
+	while ((p = strchr(p, from)) != NULL)
+		*p++ = to;
+
+	return s;
+}