gru: fix prefetch and speculation bugs
Fix several bugs related to prefetch, ordering & speculation:
- GRU cch_allocate() instruction causes cacheable memory
to be created. Add a barriers to prevent speculation
from prefetching data before it exists.
- Add memory barriers before cache-flush instructions to ensure
that previously stored data is included in the line flushed to memory.
Signed-off-by: Jack Steiner <steiner@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/misc/sgi-gru/grukservices.c b/drivers/misc/sgi-gru/grukservices.c
index 24ec109..8c81aca 100644
--- a/drivers/misc/sgi-gru/grukservices.c
+++ b/drivers/misc/sgi-gru/grukservices.c
@@ -395,6 +395,7 @@
cbrnum = thread_cbr_number(bs->bs_kgts, get_cb_number(cb));
cbe = get_cbe(GRUBASE(cb), cbrnum);
gru_flush_cache(cbe); /* CBE not coherent */
+ sync_core();
excdet->opc = cbe->opccpy;
excdet->exopc = cbe->exopccpy;
excdet->ecause = cbe->ecause;
@@ -461,9 +462,10 @@
int ret;
ret = gen->istatus;
- if (ret != CBS_EXCEPTION)
- return ret;
- return gru_retry_exception(cb);
+ if (ret == CBS_EXCEPTION)
+ ret = gru_retry_exception(cb);
+ rmb();
+ return ret;
}
@@ -475,7 +477,7 @@
ret = gru_wait_idle_or_exception(gen);
if (ret == CBS_EXCEPTION)
ret = gru_retry_exception(cb);
-
+ rmb();
return ret;
}