drm/i915: Print the batchbuffer offset next to BBADDR in error state

It is useful when looking at captured error states to check the recorded
BBADDR register (the address of the last batchbuffer instruction loaded)
against the expected offset of the batch buffer, and so do a quick check
that (a) the capture is true or (b) HEAD hasn't wandered off into the
badlands.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1471254551-25805-30-git-send-email-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_drv.h

@@ -775,6 +775,7 @@ struct drm_i915_error_state {
 		struct drm_i915_error_object {
 			int page_count;
 			u64 gtt_offset;
+			u64 gtt_size;
 			u32 *pages[0];
 		} *ringbuffer, *batchbuffer, *wa_batchbuffer, *ctx, *hws_page;
 

drivers/gpu/drm/i915/i915_gpu_error.c

@@ -242,8 +242,16 @@ static void error_print_engine(struct drm_i915_error_state_buf *m,
 	err_printf(m, "  IPEIR: 0x%08x\n", ee->ipeir);
 	err_printf(m, "  IPEHR: 0x%08x\n", ee->ipehr);
 	err_printf(m, "  INSTDONE: 0x%08x\n", ee->instdone);
+	if (ee->batchbuffer) {
+		u64 start = ee->batchbuffer->gtt_offset;
+		u64 end = start + ee->batchbuffer->gtt_size;
+
+		err_printf(m, "  batch: [0x%08x_%08x, 0x%08x_%08x]\n",
+			   upper_32_bits(start), lower_32_bits(start),
+			   upper_32_bits(end), lower_32_bits(end));
+	}
 	if (INTEL_GEN(m->i915) >= 4) {
-		err_printf(m, "  BBADDR: 0x%08x %08x\n",
+		err_printf(m, "  BBADDR: 0x%08x_%08x\n",
 			   (u32)(ee->bbaddr>>32), (u32)ee->bbaddr);
 		err_printf(m, "  BB_STATE: 0x%08x\n", ee->bbstate);
 		err_printf(m, "  INSTPS: 0x%08x\n", ee->instps);
@@ -677,7 +685,10 @@ i915_error_object_create(struct drm_i915_private *dev_priv,
 	if (!dst)
 		return NULL;
 
-	reloc_offset = dst->gtt_offset = vma->node.start;
+	dst->gtt_offset = vma->node.start;
+	dst->gtt_size = vma->node.size;
+
+	reloc_offset = dst->gtt_offset;
 	use_ggtt = (src->cache_level == I915_CACHE_NONE &&
 		   (vma->flags & I915_VMA_GLOBAL_BIND) &&
 		   reloc_offset + num_pages * PAGE_SIZE <= ggtt->mappable_end);