This patch makes the /proc/<PID>/maps file easier to parse (both for humans
and for applications), by annotating the heap, stack and vdso mappings with
[heap], [stack] and [vdso] markers.

It makes it easier/faster to determine at a quick glance whether an
application has a secure VM layout, and it also makes it easier for tools
to determine whether e.g.  the heap or stack is executable or not.

new maps file, on a patched kernel:

 001c4000-001d9000 r-xp 00000000 03:01 19954      /lib/ld-2.3.3.so
 001d9000-001db000 rw-p 00014000 03:01 19954      /lib/ld-2.3.3.so
 001dd000-002fb000 r-xp 00000000 03:01 19960      /lib/tls/libc-2.3.3.so
 002fb000-002fd000 r--p 0011d000 03:01 19960      /lib/tls/libc-2.3.3.so
 002fd000-002ff000 rw-p 0011f000 03:01 19960      /lib/tls/libc-2.3.3.so
 002ff000-00301000 rw-p 002ff000 00:00 0
 08048000-0804c000 r-xp 00000000 03:01 31968      /bin/cat
 0804c000-0804d000 rw-p 00003000 03:01 31968      /bin/cat
 0804d000-0806e000 rw-p 0804d000 00:00 0          [heap]
 b7dbc000-b7dbd000 r--p 009d1000 03:01 83628      /usr/lib/locale/locale-archive
 b7dbd000-b7dc4000 r--p 0097d000 03:01 83628      /usr/lib/locale/locale-archive
 b7dc4000-b7df1000 r--p 0094a000 03:01 83628      /usr/lib/locale/locale-archive
 b7df1000-b7ff1000 r--p 00000000 03:01 83628      /usr/lib/locale/locale-archive
 b7ff1000-b7ff2000 rw-p b7ff1000 00:00 0
 bffeb000-c0000000 rw-p bffeb000 00:00 0          [stack]
 ffffe000-fffff000 ---p 00000000 00:00 0          [vdso]

Tested on x86, but should work on all architectures.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>