tree 7e27688729d6cff7b654e87403d3176a358cfce0
parent 457fb605834504af294916411be128a9b21fc3f6
author Heiko Carstens <heiko.carstens@de.ibm.com> 1206030818 +0100
committer Martin Schwidefsky <schwidefsky@de.ibm.com> 1206030826 +0100

[S390] futex: let futex_atomic_cmpxchg_pt survive early functional tests.

a0c1e9073ef7428a14309cba010633a6cd6719ea "futex: runtime enable pi and
robust functionality" introduces a test wether futex in atomic stuff
works or not.
It does that by writing to address 0 of the kernel address space. This
will crash on older machines where addressing mode switching is enabled
but where the mvcos instruction is not available. Page table walking is
done by hand and therefore the code tries to access current->mm which
is NULL.
Therefore add an extra check, so we survive the early test.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>