--- a/xlators/encryption/rot-13/src/rot-13.c	2014-02-04 07:36:03.000000000 -0500
+++ b/xlators/encryption/rot-13/src/rot-13.c	2014-10-07 17:01:39.863969500 -0400
@@ -26,10 +26,62 @@
  * writing to disk and rot13's it back when reading it.
  * This xlator is meant as an example, NOT FOR PRODUCTION
  * USE ;) (hence no error-checking)
  */
 
+#ifdef __s390__
+static const char trTab[256] = {
+/* 00 */ 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 
+/* 08 */ 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
+/* 10 */ 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
+/* 18 */ 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
+/* 20 */ 0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27,
+/* 28 */ 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,
+/* 30 */ 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,
+/* 38 */ 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f,
+/* 40 */ 0x40, 0x4e, 0x4f, 0x50, 0x51, 0x52, 0x53, 0x54, 
+/* 48 */ 0x55, 0x56, 0x57, 0x58, 0x59, 0x5a, 0x41, 0x42, 
+/* 50 */ 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4a, 
+/* 58 */ 0x4b, 0x4c, 0x4d, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f,
+/* 60 */ 0x60, 0x6e, 0x6f, 0x70, 0x71, 0x72, 0x73, 0x74, 
+/* 68 */ 0x75, 0x76, 0x77, 0x78, 0x79, 0x7a, 0x61, 0x62, 
+/* 70 */ 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6a, 
+/* 78 */ 0x6b, 0x6c, 0x6d, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f,
+/* 80 */ 0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
+/* 88 */ 0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f,
+/* 90 */ 0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97,
+/* 98 */ 0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f,
+/* a0 */ 0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7,
+/* a8 */ 0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf,
+/* b0 */ 0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7,
+/* b8 */ 0xb8, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf,
+/* c0 */ 0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7,
+/* c8 */ 0xc8, 0xc9, 0xca, 0xcb, 0xcc, 0xcd, 0xce, 0xcf,
+/* d0 */ 0xd0, 0xd1, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7,
+/* d8 */ 0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0xdd, 0xde, 0xdf,
+/* e0 */ 0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7,
+/* e8 */ 0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef,
+/* f0 */ 0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7,
+/* f8 */ 0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff
+				};
+
+void
+rot13 (char *buf, int len)
+{
+	__asm__ ("	lg	2,%0\n"
+		 "	lgr	4,2\n"
+		 "	lgfr	3,%1\n"
+		 "	la	1,%2\n"
+		 "0:	troo	2,4,0\n"
+		 "	jo	0b\n"
+		 : "+m" (buf) 
+		 : "r" (len), "m" (trTab) 
+		 : "1", "2", "3", "4", "cc");
+}
+
+#else
+
 void
 rot13 (char *buf, int len)
 {
 	int i;
 	for (i = 0; i < len; i++) {
@@ -38,10 +90,12 @@
 		else if (buf[i] >= 'A' && buf[i] <= 'Z')
 			buf[i] = 'A' + ((buf[i] - 'A' + 13) % 26);
 	}
 }
 
+#endif
+
 void
 rot13_iovec (struct iovec *vector, int count)
 {
 	int i;
 	for (i = 0; i < count; i++) {