diff --git a/drivers/misc/sgi-gru/grufault.c b/drivers/misc/sgi-gru/grufault.c
index 2605edf..a9f0cf4 100644
--- a/drivers/misc/sgi-gru/grufault.c
+++ b/drivers/misc/sgi-gru/grufault.c
@@ -122,22 +122,11 @@
  * is necessary to prevent the user from seeing a stale cb.istatus that will
  * change as soon as the TFH restart is complete. Races may cause an
  * occasional failure to clear the cb.istatus, but that is ok.
- *
- * If the cb address is not valid (should not happen, but...), nothing
- * bad will happen.. The get_user()/put_user() will fail but there
- * are no bad side-effects.
  */
-static void gru_cb_set_istatus_active(unsigned long __user *cb)
+static void gru_cb_set_istatus_active(struct gru_instruction_bits *cbk)
 {
-	union {
-		struct gru_instruction_bits bits;
-		unsigned long dw;
-	} u;
-
-	if (cb) {
-		get_user(u.dw, cb);
-		u.bits.istatus = CBS_ACTIVE;
-		put_user(u.dw, cb);
+	if (cbk) {
+		cbk->istatus = CBS_ACTIVE;
 	}
 }
 
@@ -322,9 +311,9 @@
  */
 static int gru_try_dropin(struct gru_thread_state *gts,
 			  struct gru_tlb_fault_handle *tfh,
-			  unsigned long __user *cb)
+			  struct gru_instruction_bits *cbk)
 {
-	int pageshift = 0, asid, write, ret, atomic = !cb;
+	int pageshift = 0, asid, write, ret, atomic = !cbk;
 	unsigned long gpa = 0, vaddr = 0;
 
 	/*
@@ -347,7 +336,7 @@
 	}
 	if (tfh->state == TFHSTATE_IDLE)
 		goto failidle;
-	if (tfh->state == TFHSTATE_MISS_FMM && cb)
+	if (tfh->state == TFHSTATE_MISS_FMM && cbk)
 		goto failfmm;
 
 	write = (tfh->cause & TFHCAUSE_TLB_MOD) != 0;
@@ -378,7 +367,7 @@
 			goto failupm;
 		}
 	}
-	gru_cb_set_istatus_active(cb);
+	gru_cb_set_istatus_active(cbk);
 	tfh_write_restart(tfh, gpa, GAA_RAM, vaddr, asid, write,
 			  GRU_PAGESIZE(pageshift));
 	STAT(tlb_dropin);
@@ -392,7 +381,7 @@
 	/* No asid (delayed unload). */
 	STAT(tlb_dropin_fail_no_asid);
 	gru_dbg(grudev, "FAILED no_asid tfh: 0x%p, vaddr 0x%lx\n", tfh, vaddr);
-	if (!cb)
+	if (!cbk)
 		tfh_user_polling_mode(tfh);
 	else
 		gru_flush_cache(tfh);
@@ -415,17 +404,18 @@
 failnoexception:
 	/* TFH status did not show exception pending */
 	gru_flush_cache(tfh);
-	if (cb)
-		gru_flush_cache(cb);
+	if (cbk)
+		gru_flush_cache(cbk);
 	STAT(tlb_dropin_fail_no_exception);
-	gru_dbg(grudev, "FAILED non-exception tfh: 0x%p, status %d, state %d\n", tfh, tfh->status, tfh->state);
+	gru_dbg(grudev, "FAILED non-exception tfh: 0x%p, status %d, state %d\n",
+		tfh, tfh->status, tfh->state);
 	return 0;
 
 failidle:
 	/* TFH state was idle  - no miss pending */
 	gru_flush_cache(tfh);
-	if (cb)
-		gru_flush_cache(cb);
+	if (cbk)
+		gru_flush_cache(cbk);
 	STAT(tlb_dropin_fail_idle);
 	gru_dbg(grudev, "FAILED idle tfh: 0x%p, state %d\n", tfh, tfh->state);
 	return 0;
@@ -439,7 +429,7 @@
 
 failactive:
 	/* Range invalidate active. Switch to UPM iff atomic */
-	if (!cb)
+	if (!cbk)
 		tfh_user_polling_mode(tfh);
 	else
 		gru_flush_cache(tfh);
@@ -512,7 +502,7 @@
 
 static int gru_user_dropin(struct gru_thread_state *gts,
 			   struct gru_tlb_fault_handle *tfh,
-			   unsigned long __user *cb)
+			   void *cb)
 {
 	struct gru_mm_struct *gms = gts->ts_gms;
 	int ret;
@@ -538,7 +528,7 @@
 {
 	struct gru_tlb_fault_handle *tfh;
 	struct gru_thread_state *gts;
-	unsigned long __user *cbp;
+	void *cbk;
 	int ucbnum, cbrnum, ret = -EINVAL;
 
 	STAT(call_os);
@@ -548,7 +538,6 @@
 	ucbnum = get_cb_number((void *)cb);
 	if ((cb & (GRU_HANDLE_STRIDE - 1)) || ucbnum >= GRU_NUM_CB)
 		return -EINVAL;
-	cbp = (unsigned long *)cb;
 
 	gts = gru_find_lock_gts(cb);
 	if (!gts)
@@ -583,7 +572,9 @@
 		gru_unload_context(gts, 1);
 	} else if (gts->ts_gru) {
 		tfh = get_tfh_by_index(gts->ts_gru, cbrnum);
-		ret = gru_user_dropin(gts, tfh, cbp);
+		cbk = get_gseg_base_address_cb(gts->ts_gru->gs_gru_base_vaddr,
+				gts->ts_ctxnum, ucbnum);
+		ret = gru_user_dropin(gts, tfh, cbk);
 	}
 exit:
 	gru_unlock_gts(gts);