[PATCH 11/13] [DEBUG] dump before data for comparison

[Robert Beckett]

---
 drivers/gpu/drm/i915/gt/selftest_reset.c | 33 +++++++++++++++++++++---
 1 file changed, 30 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/selftest_reset.c b/drivers/gpu/drm/i915/gt/selftest_reset.c
index 75bc7d90c9dc..f8d4b13d7e1b 100644
--- a/drivers/gpu/drm/i915/gt/selftest_reset.c
+++ b/drivers/gpu/drm/i915/gt/selftest_reset.c
@@ -4,6 +4,7 @@
  */
 
 #include <linux/crc32.h>
+#include <linux/highmem.h>
 
 #include "gem/i915_gem_stolen.h"
 #include "intel_region_ttm.h"
@@ -31,6 +32,13 @@ __igt_reset_stolen(struct intel_gt *gt,
 	void *tmp;
 	u32 *crc;
 	int err;
+	struct page **orig;
+
+	/* TODO: BOB_DEBUG
+	 * use alloc_pages_bulk_array() to create shadow pages for each stolen page.
+	 * when calculating the crc, also kmap, copy the data, kunmap
+	 * if error, dump the original data too.
+	 */
 
 	if (!drm_mm_node_allocated(&ggtt->error_capture))
 		return 0;
@@ -39,9 +47,17 @@ __igt_reset_stolen(struct intel_gt *gt,
 	if (!num_pages)
 		return 0;
 
-	crc = kmalloc_array(num_pages, sizeof(u32), GFP_KERNEL);
-	if (!crc)
+	orig = kmalloc_array(num_pages, sizeof(struct page *), GFP_KERNEL);
+	if (!orig) {
+		pr_err("BOB_DEBUG: %s(): failed to alloc orig. sz=0x%llx\n", __func__, num_pages * sizeof(struct page*));
 		return -ENOMEM;
+	}
+
+	crc = kmalloc_array(num_pages, sizeof(u32), GFP_KERNEL);
+	if (!crc) {
+		err = -ENOMEM;
+		goto err_orig;
+	}
 
 	tmp = kmalloc(PAGE_SIZE, GFP_KERNEL);
 	if (!tmp) {
@@ -103,7 +119,11 @@ __igt_reset_stolen(struct intel_gt *gt,
 		in = (void __force *)s;
 		if (i915_memcpy_from_wc(tmp, in, PAGE_SIZE))
 			in = tmp;
+		else
+			pr_err("BOB_DEBUG: %s(): i915_memcpy_from_wc() returned false. page=%ld\n", __func__, (long)page);
+
 		crc[page] = crc32_le(0, in, PAGE_SIZE);
+		memcpy_to_page(orig[page], 0, in, PAGE_SIZE);
 
 		io_mapping_unmap(s);
 	}
@@ -147,8 +167,13 @@ __igt_reset_stolen(struct intel_gt *gt,
 		if (x != crc[page] && !busy) {
 			pr_debug("unused stolen page %pa modified by GPU reset\n",
 				 &page);
-			if (count++ == 0)
+			if (count++ == 0) {
 				igt_hexdump(in, PAGE_SIZE);
+				pr_debug("BOB_DEBUG: %s(): orig:\n", __func__);
+				in = kmap(orig[page]);
+				igt_hexdump(in, PAGE_SIZE);
+				kunmap(orig[page]);
+			}
 			max = page;
 		}
 
@@ -177,6 +202,8 @@ __igt_reset_stolen(struct intel_gt *gt,
 	kfree(tmp);
 err_crc:
 	kfree(crc);
+err_orig:
+	kfree(orig);
 	return err;
 }
 
-- 
2.25.1