gru: check context state on reload

Check whether the gru state being loaded into a gru is from a new context
or a previously unloaded context.  If new, simply zero out the hardware
context; if unloaded and valid, reload the old state.

This change is primarily for reloading kernel contexts where the previous
is not required to be saved.

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>

2 files changed, 25 insertions, 9 deletions

diff --git a/drivers/misc/sgi-gru/grumain.c b/drivers/misc/sgi-gru/grumain.c
index 4e6e8c3554f0..afc4c473c794 100644
--- a/drivers/misc/sgi-gru/grumain.c
+++ b/drivers/misc/sgi-gru/grumain.c
@@ -307,11 +307,12 @@ struct gru_thread_state *gru_alloc_gts(struct vm_area_struct *vma,
 
         bytes = DSR_BYTES(dsr_au_count) + CBR_BYTES(cbr_au_count);
         bytes += sizeof(struct gru_thread_state);
-        gts = kzalloc(bytes, GFP_KERNEL);
+        gts = kmalloc(bytes, GFP_KERNEL);
         if (!gts)
                 return NULL;
 
         STAT(gts_alloc);
+        memset(gts, 0, sizeof(struct gru_thread_state)); /* zero out header */
         atomic_set(&gts->ts_refcnt, 1);
         mutex_init(&gts->ts_ctxlock);
         gts->ts_cbr_au_count = cbr_au_count;
@@ -458,7 +459,8 @@ static void gru_prefetch_context(void *gseg, void *cb, void *cbe,
 }
 
 static void gru_load_context_data(void *save, void *grubase, int ctxnum,
-                                  unsigned long cbrmap, unsigned long dsrmap)
+                                  unsigned long cbrmap, unsigned long dsrmap,
+                                  int data_valid)
 {
         void *gseg, *cb, *cbe;
         unsigned long length;
@@ -471,12 +473,22 @@ static void gru_load_context_data(void *save, void *grubase, int ctxnum,
         gru_prefetch_context(gseg, cb, cbe, cbrmap, length);
 
         for_each_cbr_in_allocation_map(i, &cbrmap, scr) {
-                save += gru_copy_handle(cb, save);
-                save += gru_copy_handle(cbe + i * GRU_HANDLE_STRIDE, save);
+                if (data_valid) {
+                        save += gru_copy_handle(cb, save);
+                        save += gru_copy_handle(cbe + i * GRU_HANDLE_STRIDE,
+                                                save);
+                } else {
+                        memset(cb, 0, GRU_CACHE_LINE_BYTES);
+                        memset(cbe + i * GRU_HANDLE_STRIDE, 0,
+                                                GRU_CACHE_LINE_BYTES);
+                }
                 cb += GRU_HANDLE_STRIDE;
         }
 
-        memcpy(gseg + GRU_DS_BASE, save, length);
+        if (data_valid)
+                memcpy(gseg + GRU_DS_BASE, save, length);
+        else
+                memset(gseg + GRU_DS_BASE, 0, length);
 }
 
 static void gru_unload_context_data(void *save, void *grubase, int ctxnum,
@@ -517,10 +529,12 @@ void gru_unload_context(struct gru_thread_state *gts, int savestate)
 
         if (!is_kernel_context(gts))
                 gru_unload_mm_tracker(gru, gts);
-        if (savestate)
+        if (savestate) {
                 gru_unload_context_data(gts->ts_gdata, gru->gs_gru_base_vaddr,
                                         ctxnum, gts->ts_cbr_map,
                                         gts->ts_dsr_map);
+                gts->ts_data_valid = 1;
+        }
 
         if (cch_deallocate(cch))
                 BUG();
@@ -576,7 +590,7 @@ void gru_load_context(struct gru_thread_state *gts)
         }
 
         gru_load_context_data(gts->ts_gdata, gru->gs_gru_base_vaddr, ctxnum,
-                              gts->ts_cbr_map, gts->ts_dsr_map);
+                        gts->ts_cbr_map, gts->ts_dsr_map, gts->ts_data_valid);
 
         if (cch_start(cch))
                 BUG();
@@ -611,8 +625,8 @@ int gru_update_cch(struct gru_thread_state *gts, int force_unload)
                         gts->ts_tlb_int_select = gru_cpu_fault_map_id();
                         cch->tlb_int_select = gru_cpu_fault_map_id();
                         cch->tfm_fault_bit_enable =
-                                (gts->ts_user_options == GRU_OPT_MISS_FMM_POLL
-                                || gts->ts_user_options == GRU_OPT_MISS_FMM_INTR);
+                          (gts->ts_user_options == GRU_OPT_MISS_FMM_POLL
+                            || gts->ts_user_options == GRU_OPT_MISS_FMM_INTR);
                 } else {
                         for (i = 0; i < 8; i++)
                                 cch->asid[i] = 0;
diff --git a/drivers/misc/sgi-gru/grutables.h b/drivers/misc/sgi-gru/grutables.h
index 1c85fdcf5d37..5f8f3bda2fa9 100644
--- a/drivers/misc/sgi-gru/grutables.h
+++ b/drivers/misc/sgi-gru/grutables.h
@@ -385,6 +385,8 @@ struct gru_thread_state {
                                                    after migration */
         char                    ts_cbr_idx[GRU_CBR_AU];/* CBR numbers of each
                                                           allocated CB */
+        int                     ts_data_valid;  /* Indicates if ts_gdata has
+                                                   valid data */
         unsigned long           ts_gdata[0];    /* save area for GRU data (CB,
                                                    DS, CBE) */
 };