Xen custom %p format options.  A subset, borrowed from Linux.

All parameters to a %p option should be compatible with void*.  Regular
pointers are fine.  Numbers should make use of the _p() macro.

Symbol/Function pointers:

       %ps     Symbol name with condition offset and size (iff offset != 0)
                 e.g.  printk
                       default_idle+0x78/0x7d

       %pS     Symbol name with unconditional offset and size
                 e.g.  printk+0/0x48
                       default_idle+0x78/0x7d

       In the case that an appropriate symbol name can't be found, %p[sS] will
       fall back to '%p' and print the address in hex.