gru: fix cache coherency issues with instruction retry

Fix two problems related to GRU instruction failures.  Cache coherency is
not maintained for CBEs except when loading or unloading contexts.  When
reading a CBE to extract error information, the CBE must first be flushed
from the cache.

The function that reads kerrnel CBEs was reading the wrong CBE.

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>

1 files changed, 10 insertions, 2 deletions

diff --git a/drivers/misc/sgi-gru/grukservices.c b/drivers/misc/sgi-gru/grukservices.c
index ba6fcd963f30..7586b89fd0d3 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;
 }