1 files changed, 95 insertions, 61 deletions

diff --git a/drivers/gpu/drm/xe/xe_devcoredump.c b/drivers/gpu/drm/xe/xe_devcoredump.c
index 81dc7795c065..203e3038cc81 100644
--- a/drivers/gpu/drm/xe/xe_devcoredump.c
+++ b/drivers/gpu/drm/xe/xe_devcoredump.c
@@ -80,7 +80,8 @@ static struct xe_guc *exec_queue_to_guc(struct xe_exec_queue *q)
 	return &q->gt->uc.guc;
 }
 
-static ssize_t __xe_devcoredump_read(char *buffer, size_t count,
+static ssize_t __xe_devcoredump_read(char *buffer, ssize_t count,
+				     ssize_t start,
 				     struct xe_devcoredump *coredump)
 {
 	struct xe_device *xe;
@@ -94,7 +95,7 @@ static ssize_t __xe_devcoredump_read(char *buffer, size_t count,
 	ss = &coredump->snapshot;
 
 	iter.data = buffer;
-	iter.start = 0;
+	iter.start = start;
 	iter.remain = count;
 
 	p = drm_coredump_printer(&iter);
@@ -119,11 +120,7 @@ static ssize_t __xe_devcoredump_read(char *buffer, size_t count,
 	drm_puts(&p, "\n**** GuC CT ****\n");
 	xe_guc_ct_snapshot_print(ss->guc.ct, &p);
 
-	/*
-	 * Don't add a new section header here because the mesa debug decoder
-	 * tool expects the context information to be in the 'GuC CT' section.
-	 */
-	/* drm_puts(&p, "\n**** Contexts ****\n"); */
+	drm_puts(&p, "\n**** Contexts ****\n");
 	xe_guc_exec_queue_snapshot_print(ss->ge, &p);
 
 	drm_puts(&p, "\n**** Job ****\n");
@@ -172,12 +169,34 @@ static void xe_devcoredump_snapshot_free(struct xe_devcoredump_snapshot *ss)
 	ss->vm = NULL;
 }
 
+#define XE_DEVCOREDUMP_CHUNK_MAX	(SZ_512M + SZ_1G)
+
+/**
+ * xe_devcoredump_read() - Read data from the Xe device coredump snapshot
+ * @buffer: Destination buffer to copy the coredump data into
+ * @offset: Offset in the coredump data to start reading from
+ * @count: Number of bytes to read
+ * @data: Pointer to the xe_devcoredump structure
+ * @datalen: Length of the data (unused)
+ *
+ * Reads a chunk of the coredump snapshot data into the provided buffer.
+ * If the devcoredump is smaller than 1.5 GB (XE_DEVCOREDUMP_CHUNK_MAX),
+ * it is read directly from a pre-written buffer. For larger devcoredumps,
+ * the pre-written buffer must be periodically repopulated from the snapshot
+ * state due to kmalloc size limitations.
+ *
+ * Return: Number of bytes copied on success, or a negative error code on failure.
+ */
 static ssize_t xe_devcoredump_read(char *buffer, loff_t offset,
 				   size_t count, void *data, size_t datalen)
 {
 	struct xe_devcoredump *coredump = data;
 	struct xe_devcoredump_snapshot *ss;
-	ssize_t byte_copied;
+	ssize_t byte_copied = 0;
+	u32 chunk_offset;
+	ssize_t new_chunk_position;
+	bool pm_needed = false;
+	int ret = 0;
 
 	if (!coredump)
 		return -ENODEV;
@@ -187,25 +206,45 @@ static ssize_t xe_devcoredump_read(char *buffer, loff_t offset,
 	/* Ensure delayed work is captured before continuing */
 	flush_work(&ss->work);
 
+	pm_needed = ss->read.size > XE_DEVCOREDUMP_CHUNK_MAX;
+	if (pm_needed)
+		xe_pm_runtime_get(gt_to_xe(ss->gt));
+
 	mutex_lock(&coredump->lock);
 
 	if (!ss->read.buffer) {
-		mutex_unlock(&coredump->lock);
-		return -ENODEV;
+		ret = -ENODEV;
+		goto unlock;
 	}
 
-	if (offset >= ss->read.size) {
-		mutex_unlock(&coredump->lock);
-		return 0;
+	if (offset >= ss->read.size)
+		goto unlock;
+
+	new_chunk_position = div_u64_rem(offset,
+					 XE_DEVCOREDUMP_CHUNK_MAX,
+					 &chunk_offset);
+
+	if (offset >= ss->read.chunk_position + XE_DEVCOREDUMP_CHUNK_MAX ||
+	    offset < ss->read.chunk_position) {
+		ss->read.chunk_position = new_chunk_position *
+			XE_DEVCOREDUMP_CHUNK_MAX;
+
+		__xe_devcoredump_read(ss->read.buffer,
+				      XE_DEVCOREDUMP_CHUNK_MAX,
+				      ss->read.chunk_position, coredump);
 	}
 
 	byte_copied = count < ss->read.size - offset ? count :
 		ss->read.size - offset;
-	memcpy(buffer, ss->read.buffer + offset, byte_copied);
+	memcpy(buffer, ss->read.buffer + chunk_offset, byte_copied);
 
+unlock:
 	mutex_unlock(&coredump->lock);
 
-	return byte_copied;
+	if (pm_needed)
+		xe_pm_runtime_put(gt_to_xe(ss->gt));
+
+	return byte_copied ? byte_copied : ret;
 }
 
 static void xe_devcoredump_free(void *data)
@@ -241,7 +280,7 @@ static void xe_devcoredump_deferred_snap_work(struct work_struct *work)
 
 	/*
 	 * NB: Despite passing a GFP_ flags parameter here, more allocations are done
-	 * internally using GFP_KERNEL expliictly. Hence this call must be in the worker
+	 * internally using GFP_KERNEL explicitly. Hence this call must be in the worker
 	 * thread and not in the initial capture call.
 	 */
 	dev_coredumpm_timeout(gt_to_xe(ss->gt)->drm.dev, THIS_MODULE, coredump, 0, GFP_KERNEL,
@@ -258,17 +297,32 @@ static void xe_devcoredump_deferred_snap_work(struct work_struct *work)
 	xe_guc_exec_queue_snapshot_capture_delayed(ss->ge);
 	xe_force_wake_put(gt_to_fw(ss->gt), fw_ref);
 
-	xe_pm_runtime_put(xe);
+	ss->read.chunk_position = 0;
 
 	/* Calculate devcoredump size */
-	ss->read.size = __xe_devcoredump_read(NULL, INT_MAX, coredump);
-
-	ss->read.buffer = kvmalloc(ss->read.size, GFP_USER);
-	if (!ss->read.buffer)
-		return;
+	ss->read.size = __xe_devcoredump_read(NULL, LONG_MAX, 0, coredump);
+
+	if (ss->read.size > XE_DEVCOREDUMP_CHUNK_MAX) {
+		ss->read.buffer = kvmalloc(XE_DEVCOREDUMP_CHUNK_MAX,
+					   GFP_USER);
+		if (!ss->read.buffer)
+			goto put_pm;
+
+		__xe_devcoredump_read(ss->read.buffer,
+				      XE_DEVCOREDUMP_CHUNK_MAX,
+				      0, coredump);
+	} else {
+		ss->read.buffer = kvmalloc(ss->read.size, GFP_USER);
+		if (!ss->read.buffer)
+			goto put_pm;
+
+		__xe_devcoredump_read(ss->read.buffer, ss->read.size, 0,
+				      coredump);
+		xe_devcoredump_snapshot_free(ss);
+	}
 
-	__xe_devcoredump_read(ss->read.buffer, ss->read.size, coredump);
-	xe_devcoredump_snapshot_free(ss);
+put_pm:
+	xe_pm_runtime_put(xe);
 }
 
 static void devcoredump_snapshot(struct xe_devcoredump *coredump,
@@ -277,13 +331,9 @@ static void devcoredump_snapshot(struct xe_devcoredump *coredump,
 {
 	struct xe_devcoredump_snapshot *ss = &coredump->snapshot;
 	struct xe_guc *guc = exec_queue_to_guc(q);
-	u32 adj_logical_mask = q->logical_mask;
-	u32 width_mask = (0x1 << q->width) - 1;
 	const char *process_name = "no process";
-
 	unsigned int fw_ref;
 	bool cookie;
-	int i;
 
 	ss->snapshot_time = ktime_get_real();
 	ss->boot_time = ktime_get_boottime();
@@ -299,14 +349,6 @@ static void devcoredump_snapshot(struct xe_devcoredump *coredump,
 	INIT_WORK(&ss->work, xe_devcoredump_deferred_snap_work);
 
 	cookie = dma_fence_begin_signalling();
-	for (i = 0; q->width > 1 && i < XE_HW_ENGINE_MAX_INSTANCE;) {
-		if (adj_logical_mask & BIT(i)) {
-			adj_logical_mask |= width_mask << i;
-			i += q->width;
-		} else {
-			++i;
-		}
-	}
 
 	/* keep going if fw fails as we still want to save the memory and SW data */
 	fw_ref = xe_force_wake_get(gt_to_fw(q->gt), XE_FORCEWAKE_ALL);
@@ -395,51 +437,43 @@ int xe_devcoredump_init(struct xe_device *xe)
 /**
  * xe_print_blob_ascii85 - print a BLOB to some useful location in ASCII85
  *
- * The output is split to multiple lines because some print targets, e.g. dmesg
- * cannot handle arbitrarily long lines. Note also that printing to dmesg in
- * piece-meal fashion is not possible, each separate call to drm_puts() has a
- * line-feed automatically added! Therefore, the entire output line must be
- * constructed in a local buffer first, then printed in one atomic output call.
+ * The output is split into multiple calls to drm_puts() because some print
+ * targets, e.g. dmesg, cannot handle arbitrarily long lines. These targets may
+ * add newlines, as is the case with dmesg: each drm_puts() call creates a
+ * separate line.
  *
  * There is also a scheduler yield call to prevent the 'task has been stuck for
  * 120s' kernel hang check feature from firing when printing to a slow target
  * such as dmesg over a serial port.
  *
- * TODO: Add compression prior to the ASCII85 encoding to shrink huge buffers down.
- *
  * @p: the printer object to output to
  * @prefix: optional prefix to add to output string
+ * @suffix: optional suffix to add at the end. 0 disables it and is
+ *          not added to the output, which is useful when using multiple calls
+ *          to dump data to @p
  * @blob: the Binary Large OBject to dump out
  * @offset: offset in bytes to skip from the front of the BLOB, must be a multiple of sizeof(u32)
  * @size: the size in bytes of the BLOB, must be a multiple of sizeof(u32)
  */
-void xe_print_blob_ascii85(struct drm_printer *p, const char *prefix,
+void xe_print_blob_ascii85(struct drm_printer *p, const char *prefix, char suffix,
 			   const void *blob, size_t offset, size_t size)
 {
 	const u32 *blob32 = (const u32 *)blob;
 	char buff[ASCII85_BUFSZ], *line_buff;
 	size_t line_pos = 0;
 
-	/*
-	 * Splitting blobs across multiple lines is not compatible with the mesa
-	 * debug decoder tool. Note that even dropping the explicit '\n' below
-	 * doesn't help because the GuC log is so big some underlying implementation
-	 * still splits the lines at 512K characters. So just bail completely for
-	 * the moment.
-	 */
-	return;
-
 #define DMESG_MAX_LINE_LEN	800
-#define MIN_SPACE		(ASCII85_BUFSZ + 2)		/* 85 + "\n\0" */
+	/* Always leave space for the suffix char and the \0 */
+#define MIN_SPACE		(ASCII85_BUFSZ + 2)	/* 85 + "<suffix>\0" */
 
 	if (size & 3)
 		drm_printf(p, "Size not word aligned: %zu", size);
 	if (offset & 3)
-		drm_printf(p, "Offset not word aligned: %zu", size);
+		drm_printf(p, "Offset not word aligned: %zu", offset);
 
-	line_buff = kzalloc(DMESG_MAX_LINE_LEN, GFP_KERNEL);
-	if (IS_ERR_OR_NULL(line_buff)) {
-		drm_printf(p, "Failed to allocate line buffer: %pe", line_buff);
+	line_buff = kzalloc(DMESG_MAX_LINE_LEN, GFP_ATOMIC);
+	if (!line_buff) {
+		drm_printf(p, "Failed to allocate line buffer\n");
 		return;
 	}
 
@@ -462,7 +496,6 @@ void xe_print_blob_ascii85(struct drm_printer *p, const char *prefix,
 		line_pos += strlen(line_buff + line_pos);
 
 		if ((line_pos + MIN_SPACE) >= DMESG_MAX_LINE_LEN) {
-			line_buff[line_pos++] = '\n';
 			line_buff[line_pos++] = 0;
 
 			drm_puts(p, line_buff);
@@ -474,10 +507,11 @@ void xe_print_blob_ascii85(struct drm_printer *p, const char *prefix,
 		}
 	}
 
+	if (suffix)
+		line_buff[line_pos++] = suffix;
+
 	if (line_pos) {
-		line_buff[line_pos++] = '\n';
 		line_buff[line_pos++] = 0;
-
 		drm_puts(p, line_buff);
 	}