1 files changed, 18 insertions, 2 deletions

diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index d4996cf46eb6..dc48d2b32ebd 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -25,6 +25,7 @@
 #include <linux/kallsyms.h>
 #include <linux/uaccess.h>
 #include <linux/ioport.h>
+#include <linux/bitrev.h>
 #include <net/addrconf.h>
 
 #include <asm/page.h>           /* for PAGE_SIZE */
@@ -681,11 +682,21 @@ static char *mac_address_string(char *buf, char *end, u8 *addr,
         char mac_addr[sizeof("xx:xx:xx:xx:xx:xx")];
         char *p = mac_addr;
         int i;
+        bool bitrev;
+        char separator;
+
+        if (fmt[1] == 'F') {            /* FDDI canonical format */
+                bitrev = true;
+                separator = '-';
+        } else {
+                bitrev = false;
+                separator = ':';
+        }
 
         for (i = 0; i < 6; i++) {
-                p = pack_hex_byte(p, addr[i]);
+                p = pack_hex_byte(p, bitrev ? bitrev8(addr[i]) : addr[i]);
                 if (fmt[0] == 'M' && i != 5)
-                        *p++ = ':';
+                        *p++ = separator;
         }
         *p = '\0';
 
@@ -896,6 +907,10 @@ static char *uuid_string(char *buf, char *end, const u8 *addr,
  * - 'M' For a 6-byte MAC address, it prints the address in the
  *       usual colon-separated hex notation
  * - 'm' For a 6-byte MAC address, it prints the hex address without colons
+ * - 'MF' For a 6-byte MAC FDDI address, it prints the address
+ *       with a dash-separated hex notation with bit reversed bytes
+ * - 'mF' For a 6-byte MAC FDDI address, it prints the address
+ *       in hex notation without separators with bit reversed bytes
  * - 'I' [46] for IPv4/IPv6 addresses printed in the usual way
  *       IPv4 uses dot-separated decimal without leading 0's (1.2.3.4)
  *       IPv6 uses colon separated network-order 16 bit hex with leading 0's
@@ -939,6 +954,7 @@ static char *pointer(const char *fmt, char *buf, char *end, void *ptr,
                 return resource_string(buf, end, ptr, spec, fmt);
         case 'M':                       /* Colon separated: 00:01:02:03:04:05 */
         case 'm':                       /* Contiguous: 000102030405 */
+                                        /* [mM]F (FDDI, bit reversed) */
                 return mac_address_string(buf, end, ptr, spec, fmt);
         case 'I':                       /* Formatted IP supported
                                          * 4:   1.2.3.4