drm/xe/guc: Copy GuC log prior to dumping

Add an extra stage to the GuC log print to copy the log buffer into
regular host memory first, rather than printing the live GPU buffer
object directly. Doing so helps prevent inconsistencies due to the log
being updated as it is being dumped. It also allows the use of the
ASCII85 helper function for printing the log in a more compact form
than a straight hex dump.

v2: Use %zx instead of %lx for size_t prints.
v3: Replace hexdump code with ascii85 call (review feedback from
Matthew B). Move chunking code into next patch as that reduces the
deltas of both.
v4: Add a prefix to the ASCII85 output to aid tool parsing.

Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Julia Filipchuk <julia.filipchuk@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241003004611.2323493-6-John.C.Harrison@Intel.com

Author: johnharr-intel

drivers/gpu/drm/xe/xe_guc_log.c

@@ -8,9 +8,12 @@
 #include <linux/fault-inject.h>
 
 #include <drm/drm_managed.h>
+#include <linux/vmalloc.h>
 
 #include "xe_bo.h"
+#include "xe_devcoredump.h"
 #include "xe_gt.h"
+#include "xe_gt_printk.h"
 #include "xe_map.h"
 #include "xe_module.h"
 
@@ -51,32 +54,35 @@ static size_t guc_log_size(void)
 		CAPTURE_BUFFER_SIZE;
 }
 
+/**
+ * xe_guc_log_print - dump a copy of the GuC log to some useful location
+ * @log: GuC log structure
+ * @p: the printer object to output to
+ */
 void xe_guc_log_print(struct xe_guc_log *log, struct drm_printer *p)
 {
 	struct xe_device *xe = log_to_xe(log);
 	size_t size;
-	int i, j;
+	void *copy;
 
-	xe_assert(xe, log->bo);
+	if (!log->bo) {
+		drm_puts(p, "GuC log buffer not allocated");
+		return;
+	}
 
 	size = log->bo->size;
 
-#define DW_PER_READ		128
-	xe_assert(xe, !(size % (DW_PER_READ * sizeof(u32))));
-	for (i = 0; i < size / sizeof(u32); i += DW_PER_READ) {
-		u32 read[DW_PER_READ];
-
-		xe_map_memcpy_from(xe, read, &log->bo->vmap, i * sizeof(u32),
-				   DW_PER_READ * sizeof(u32));
-#define DW_PER_PRINT		4
-		for (j = 0; j < DW_PER_READ / DW_PER_PRINT; ++j) {
-			u32 *print = read + j * DW_PER_PRINT;
-
-			drm_printf(p, "0x%08x 0x%08x 0x%08x 0x%08x\n",
-				   *(print + 0), *(print + 1),
-				   *(print + 2), *(print + 3));
-		}
+	copy = vmalloc(size);
+	if (!copy) {
+		drm_printf(p, "Failed to allocate %zu", size);
+		return;
 	}
+
+	xe_map_memcpy_from(xe, copy, &log->bo->vmap, 0, size);
+
+	xe_print_blob_ascii85(p, "Log data", copy, 0, size);
+
+	vfree(copy);
 }
 
 int xe_guc_log_init(struct xe_guc_log *log)