sgi-gru: aSID (context management) bug fixes

This patch fixes bugs related to ASID (context id) management in the GRU
driver.  These changes are all internal to the SGI GRU driver and have no
effect on the base kernel.
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>

drivers/misc/sgi-gru/grufile.c

@@ -274,6 +274,7 @@ static void gru_init_chiplet(struct gru_state *gru, unsigned long paddr,
 	gru->gs_blade_id = bid;
 	gru->gs_cbr_map = (GRU_CBR_AU == 64) ? ~0 : (1UL << GRU_CBR_AU) - 1;
 	gru->gs_dsr_map = (1UL << GRU_DSR_AU) - 1;
+	gru->gs_asid_limit = MAX_ASID;
 	gru_tgh_flush_init(gru);
 	gru_dbg(grudev, "bid %d, nid %d, gid %d, vaddr %p (0x%lx)\n",
 		bid, nid, gru->gs_gid, gru->gs_gru_base_vaddr,

drivers/misc/sgi-gru/grumain.c

@@ -79,7 +79,6 @@ static int gru_wrap_asid(struct gru_state *gru)
 	gru_dbg(grudev, "gid %d\n", gru->gs_gid);
 	STAT(asid_wrap);
 	gru->gs_asid_gen++;
-	gru_flush_all_tlb(gru);
 	return MIN_ASID;
 }
 
@@ -93,6 +92,7 @@ static int gru_reset_asid_limit(struct gru_state *gru, int asid)
 	limit = MAX_ASID;
 	if (asid >= limit)
 		asid = gru_wrap_asid(gru);
+	gru_flush_all_tlb(gru);
 	gid = gru->gs_gid;
 again:
 	for (i = 0; i < GRU_NUM_CCH; i++) {
@@ -131,12 +131,10 @@ static int gru_assign_asid(struct gru_state *gru)
 {
 	int asid;
 
-	spin_lock(&gru->gs_asid_lock);
 	gru->gs_asid += ASID_INC;
 	asid = gru->gs_asid;
 	if (asid >= gru->gs_asid_limit)
 		asid = gru_reset_asid_limit(gru, asid);
-	spin_unlock(&gru->gs_asid_lock);
 
 	gru_dbg(grudev, "gid %d, asid 0x%x\n", gru->gs_gid, asid);
 	return asid;
@@ -227,7 +225,9 @@ static int gru_load_mm_tracker(struct gru_state *gru,
 	spin_lock(&gms->ms_asid_lock);
 	asid = asids->mt_asid;
 
-	if (asid == 0 || asids->mt_asid_gen != gru->gs_asid_gen) {
+	spin_lock(&gru->gs_asid_lock);
+	if (asid == 0 || (asids->mt_ctxbitmap == 0 && asids->mt_asid_gen !=
+			  gru->gs_asid_gen)) {
 		asid = gru_assign_asid(gru);
 		asids->mt_asid = asid;
 		asids->mt_asid_gen = gru->gs_asid_gen;
@@ -235,6 +235,7 @@ static int gru_load_mm_tracker(struct gru_state *gru,
 	} else {
 		STAT(asid_reuse);
 	}
+	spin_unlock(&gru->gs_asid_lock);
 
 	BUG_ON(asids->mt_ctxbitmap & ctxbitmap);
 	asids->mt_ctxbitmap |= ctxbitmap;
@@ -259,10 +260,12 @@ static void gru_unload_mm_tracker(struct gru_state *gru,
 	asids = &gms->ms_asids[gru->gs_gid];
 	ctxbitmap = (1 << gts->ts_ctxnum);
 	spin_lock(&gms->ms_asid_lock);
+	spin_lock(&gru->gs_asid_lock);
 	BUG_ON((asids->mt_ctxbitmap & ctxbitmap) != ctxbitmap);
 	asids->mt_ctxbitmap ^= ctxbitmap;
 	gru_dbg(grudev, "gid %d, gts %p, gms %p, ctxnum 0x%d, asidmap 0x%lx\n",
 		gru->gs_gid, gts, gms, gts->ts_ctxnum, gms->ms_asidmap[0]);
+	spin_unlock(&gru->gs_asid_lock);
 	spin_unlock(&gms->ms_asid_lock);
 }
 
@@ -412,6 +415,7 @@ static void gru_free_gru_context(struct gru_thread_state *gts)
 	__clear_bit(gts->ts_ctxnum, &gru->gs_context_map);
 	gts->ts_ctxnum = NULLCTX;
 	gts->ts_gru = NULL;
+	gts->ts_blade = -1;
 	spin_unlock(&gru->gs_lock);
 
 	gts_drop(gts);
@@ -731,6 +735,7 @@ static struct gru_state *gru_assign_gru_context(struct gru_thread_state *gts)
 		}
 		reserve_gru_resources(gru, gts);
 		gts->ts_gru = gru;
+		gts->ts_blade = gru->gs_blade_id;
 		gts->ts_ctxnum =
 		    find_first_zero_bit(&gru->gs_context_map, GRU_NUM_CCH);
 		BUG_ON(gts->ts_ctxnum == GRU_NUM_CCH);