diff --git a/drivers/misc/sgi-gru/grufault.c b/drivers/misc/sgi-gru/grufault.c
index a489807613f8246ed9ebf0880959200421972442..6d0681236db5ea4bae4e1b8e0da7822d512f93c3 100644
--- a/drivers/misc/sgi-gru/grufault.c
+++ b/drivers/misc/sgi-gru/grufault.c
@@ -614,7 +614,7 @@ int gru_get_exception_detail(unsigned long arg)
 	} else if (gts->ts_gru) {
 		cbrnum = thread_cbr_number(gts, ucbnum);
 		cbe = get_cbe_by_index(gts->ts_gru, cbrnum);
-		prefetchw(cbe);/* Harmless on hardware, required for emulator */
+		gru_flush_cache(cbe);	/* CBE not coherent */
 		excdet.opc = cbe->opccpy;
 		excdet.exopc = cbe->exopccpy;
 		excdet.ecause = cbe->ecause;
@@ -622,6 +622,7 @@ int gru_get_exception_detail(unsigned long arg)
 		excdet.exceptdet1 = cbe->idef3upd;
 		excdet.cbrstate = cbe->cbrstate;
 		excdet.cbrexecstatus = cbe->cbrexecstatus;
+		gru_flush_cache(cbe);
 		ret = 0;
 	} else {
 		ret = -EAGAIN;
diff --git a/drivers/misc/sgi-gru/grufile.c b/drivers/misc/sgi-gru/grufile.c
index 796ac704795e82383f4dd1543607a0b911e45e27..bfc88d1b2a5bcae8c738537ad3ce78cd865ea73b 100644
--- a/drivers/misc/sgi-gru/grufile.c
+++ b/drivers/misc/sgi-gru/grufile.c
@@ -46,6 +46,7 @@
 
 struct gru_blade_state *gru_base[GRU_MAX_BLADES] __read_mostly;
 unsigned long gru_start_paddr __read_mostly;
+void *gru_start_vaddr __read_mostly;
 unsigned long gru_end_paddr __read_mostly;
 unsigned int gru_max_gids __read_mostly;
 struct gru_stats_s gru_stats;
@@ -376,7 +377,6 @@ static int __init gru_init(void)
 {
 	int ret, irq, chip;
 	char id[10];
-	void *gru_start_vaddr;
 
 	if (!is_uv_system())
 		return 0;
diff --git a/drivers/misc/sgi-gru/grukservices.c b/drivers/misc/sgi-gru/grukservices.c
index ba6fcd963f3054cc917f92ebf45f87db54b465bd..7586b89fd0d3a82ecb0554bf7c0130f710fa8ab9 100644
--- a/drivers/misc/sgi-gru/grukservices.c
+++ b/drivers/misc/sgi-gru/grukservices.c
@@ -98,6 +98,9 @@
 #define ASYNC_HAN_TO_BID(h)	((h) - 1)
 #define ASYNC_BID_TO_HAN(b)	((b) + 1)
 #define ASYNC_HAN_TO_BS(h)	gru_base[ASYNC_HAN_TO_BID(h)]
+#define KCB_TO_GID(cb)		((cb - gru_start_vaddr) /		\
+					(GRU_SIZE * GRU_CHIPLETS_PER_BLADE))
+#define KCB_TO_BS(cb)		gru_base[KCB_TO_GID(cb)]
 
 #define GRU_NUM_KERNEL_CBR	1
 #define GRU_NUM_KERNEL_DSR_BYTES 256
@@ -354,14 +357,19 @@ int gru_get_cb_exception_detail(void *cb,
 		struct control_block_extended_exc_detail *excdet)
 {
 	struct gru_control_block_extended *cbe;
+	struct gru_blade_state *bs;
+	int cbrnum;
 
-	cbe = get_cbe(GRUBASE(cb), get_cb_number(cb));
-	prefetchw(cbe);	/* Harmless on hardware, required for emulator */
+	bs = KCB_TO_BS(cb);
+	cbrnum = thread_cbr_number(bs->bs_kgts, get_cb_number(cb));
+	cbe = get_cbe(GRUBASE(cb), cbrnum);
+	gru_flush_cache(cbe);	/* CBE not coherent */
 	excdet->opc = cbe->opccpy;
 	excdet->exopc = cbe->exopccpy;
 	excdet->ecause = cbe->ecause;
 	excdet->exceptdet0 = cbe->idef1upd;
 	excdet->exceptdet1 = cbe->idef3upd;
+	gru_flush_cache(cbe);
 	return 0;
 }
 
diff --git a/drivers/misc/sgi-gru/grutables.h b/drivers/misc/sgi-gru/grutables.h
index 246c63883ebf92b58147164ab2d838adac9ad0fe..665704683ab8c7f3ff5631a1df6066d217d1fc79 100644
--- a/drivers/misc/sgi-gru/grutables.h
+++ b/drivers/misc/sgi-gru/grutables.h
@@ -153,6 +153,7 @@
 extern struct gru_stats_s gru_stats;
 extern struct gru_blade_state *gru_base[];
 extern unsigned long gru_start_paddr, gru_end_paddr;
+extern void *gru_start_vaddr;
 extern unsigned int gru_max_gids;
 
 #define GRU_MAX_BLADES		MAX_NUMNODES