tree f1850331426e3c1d4b0e7a20e633095f2546bf8f
parent a6cf7ed5119fb22f54584a9f867b638edd3c4384
author Jimi Xenidis <jimix@pobox.com> 1330435627 +0000
committer Benjamin Herrenschmidt <benh@kernel.crashing.org> 1331100369 +1100

powerpc/icswx: Fix race condition with IPI setting ACOP

There is a race where a thread causes a coprocessor type to be valid
in its own ACOP _and_ in the current context, but it does not
propagate to the ACOP register of other threads in time for them to
use it.  The original code tries to solve this by sending an IPI to
all threads on the system, which is heavy handed, but unfortunately
still provides a window where the icswx is issued by other threads and
the ACOP is not up to date.

This patch detects that the ACOP DSI fault was a "false positive" and
syncs the ACOP and causes the icswx to be replayed.

Signed-off-by: Jimi Xenidis <jimix@pobox.com>
Cc: Anton Blanchard <anton@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>