gru: fix bug in exception handling

Fix a GRU driver bug converting a CBR address to the context that contains
the CBR.  The conversion is rarely done so performance does not matter.

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 d9ff028..c13342d 100644 (file)
--- a/drivers/misc/sgi-gru/grukservices.c
+++ b/drivers/misc/sgi-gru/grukservices.c
@@ -97,9 +97,6 @@
 #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
@@ -388,11 +385,28 @@ 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;
-
-       bs = KCB_TO_BS(cb);
-       cbrnum = thread_cbr_number(bs->bs_kgts, get_cb_number(cb));
+       struct gru_thread_state *kgts = NULL;
+       unsigned long off;
+       int cbrnum, bid;
+
+       /*
+        * Locate kgts for cb. This algorithm is SLOW but
+        * this function is rarely called (ie., almost never).
+        * Performance does not matter.
+        */
+       for_each_possible_blade(bid) {
+               if (!gru_base[bid])
+                       break;
+               kgts = gru_base[bid]->bs_kgts;
+               if (!kgts || !kgts->ts_gru)
+                       continue;
+               off = cb - kgts->ts_gru->gs_gru_base_vaddr;
+               if (off < GRU_SIZE)
+                       break;
+               kgts = NULL;
+       }
+       BUG_ON(!kgts);
+       cbrnum = thread_cbr_number(kgts, get_cb_number(cb));
        cbe = get_cbe(GRUBASE(cb), cbrnum);
        gru_flush_cache(cbe);   /* CBE not coherent */
        sync_core();