what is the correct use of linux kernel personality?

Can someone please explain the correct use of Linux kernel personality or point me to some documentation that explains it well. We are trying to see how to make use of it with audit filters. The man page for the system call "personality" states that if you give it a 0Xffffffff the system call returns the current personality. So I wrote a little program to check this out. The program always returned 0xff or 255. on AMD iSeries and i386 platforms for 32 and 64 bit executables. It turned out that the /usr/include/linux/personality.h has the following line: #define personality(pers) (pers & PER_MASK) no wonder. PER_MASK is 0xff and the name of the syscall is also personality. Which means in my application, the system call was never called. OK, so I commented this line out. Now I get 0 for the personality on the all platforms mentioned above with 32 & 64 bit executables. Mounir Bsaibes Linux Security Tel: (512) 838-1301 Cell: (512) 762-9957 Fax: (512) 838-8858 e-mail: bsaibes(a)us.ibm.com