[PATCH 11/16] [DEBUG] dump before data for comparison

[Robert Beckett]

---
 drivers/gpu/drm/i915/gt/selftest_reset.c | 69 ++++++++++++++++++++++--
 1 file changed, 66 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..1d353576bb6b 100644
--- a/drivers/gpu/drm/i915/gt/selftest_reset.c
+++ b/drivers/gpu/drm/i915/gt/selftest_reset.c
@@ -4,6 +4,8 @@
  */
 
 #include <linux/crc32.h>
+#include <linux/highmem.h>
+#include <linux/sched/mm.h>
 
 #include "gem/i915_gem_stolen.h"
 #include "intel_region_ttm.h"
@@ -15,6 +17,47 @@
 #include "selftests/igt_atomic.h"
 #include "selftests/igt_spinner.h"
 
+static void free_orig(struct page ** pages, unsigned long num_pages)
+{
+	unsigned long page;
+	for (page = 0; page < num_pages && pages[page]; page++)
+		__free_page(pages[page]);
+
+	kvfree(pages);
+}
+
+static struct page ** alloc_orig(unsigned long num_pages)
+{
+	struct page ** pages;
+	unsigned long allocated;
+
+	pages = kvmalloc_array(num_pages, sizeof(struct page *), GFP_KERNEL | __GFP_ZERO);
+	if (!pages) {
+		pr_err("BOB_DEBUG: %s(): failed to alloc array. num_pages=%lu\n",
+				__func__, num_pages);
+		return NULL;
+	}
+
+	for (allocated = 0; allocated < num_pages; ) {
+		unsigned long previous = allocated;
+
+		allocated = alloc_pages_bulk_array(GFP_KERNEL, num_pages, pages);
+		if (previous == allocated)
+			break;
+
+		memalloc_retry_wait(GFP_KERNEL);
+	}
+
+	if (allocated < num_pages) {
+		pr_err("BOB_DEBUG: %s(): failed to alloc pages. num_pages=%lu allocated=%lu\n",
+				__func__, num_pages, allocated);
+		free_orig(pages, num_pages);
+		return NULL;
+	}
+
+	return pages;
+}
+
 static int
 __igt_reset_stolen(struct intel_gt *gt,
 		   intel_engine_mask_t mask,
@@ -31,6 +74,7 @@ __igt_reset_stolen(struct intel_gt *gt,
 	void *tmp;
 	u32 *crc;
 	int err;
+	struct page **orig;
 
 	if (!drm_mm_node_allocated(&ggtt->error_capture))
 		return 0;
@@ -39,9 +83,17 @@ __igt_reset_stolen(struct intel_gt *gt,
 	if (!num_pages)
 		return 0;
 
-	crc = kmalloc_array(num_pages, sizeof(u32), GFP_KERNEL);
-	if (!crc)
+	orig = alloc_orig(num_pages);
+	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 +155,11 @@ __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 +203,13 @@ __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 +238,8 @@ __igt_reset_stolen(struct intel_gt *gt,
 	kfree(tmp);
 err_crc:
 	kfree(crc);
+err_orig:
+	free_orig(orig, num_pages);
 	return err;
 }
 
-- 
2.25.1