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Commit 334636c6 authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915: Trim i915_guc_info() stack usage 



i915_guc_info() (part of debugfs output) tries to avoid holding
struct_mutex for a long period by copying onto the stack. This causes a
warning that the stack frame is massive, so stop doing that. We can even
forgo holding the struct_mutex here as that doesn't serialise the values
being read (and the lists used exist for the device lifetime).

v2: Skip printing anything if guc->execbuf_client is disabled (avoids
potential NULL dereference).

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/20161129121024.22650-2-chris@chris-wilson.co.uk


Reviewed-by: default avatarTvrtko Ursulin <tvrtko.ursulin@intel.com>
parent 7f9e7754

drivers/gpu/drm/i915/i915_debugfs.c

+20 −26
Original line number Diff line number Diff line
@@ -2434,47 +2434,41 @@ static void i915_guc_client_info(struct seq_file *m, 
static int i915_guc_info(struct seq_file *m, void *data)

{

	struct drm_i915_private *dev_priv = node_to_i915(m->private);

	struct drm_device *dev = &dev_priv->drm;

	struct intel_guc guc;

	struct i915_guc_client client = {};

	const struct intel_guc *guc = &dev_priv->guc;

	struct intel_engine_cs *engine;

	enum intel_engine_id id;

	u64 total = 0;



	if (!HAS_GUC_SCHED(dev_priv))

		return 0;

	u64 total;



	if (mutex_lock_interruptible(&dev->struct_mutex))

	if (!guc->execbuf_client) {

		seq_printf(m, "GuC submission %s\n",

			   HAS_GUC_SCHED(dev_priv) ?

			   "disabled" :

			   "not supported");

		return 0;



	/* Take a local copy of the GuC data, so we can dump it at leisure */

	guc = dev_priv->guc;

	if (guc.execbuf_client)

		client = *guc.execbuf_client;



	mutex_unlock(&dev->struct_mutex);

	}



	seq_printf(m, "Doorbell map:\n");

	seq_printf(m, "\t%*pb\n", GUC_MAX_DOORBELLS, guc.doorbell_bitmap);

	seq_printf(m, "Doorbell next cacheline: 0x%x\n\n", guc.db_cacheline);

	seq_printf(m, "\t%*pb\n", GUC_MAX_DOORBELLS, guc->doorbell_bitmap);

	seq_printf(m, "Doorbell next cacheline: 0x%x\n\n", guc->db_cacheline);



	seq_printf(m, "GuC total action count: %llu\n", guc.action_count);

	seq_printf(m, "GuC action failure count: %u\n", guc.action_fail);

	seq_printf(m, "GuC last action command: 0x%x\n", guc.action_cmd);

	seq_printf(m, "GuC last action status: 0x%x\n", guc.action_status);

	seq_printf(m, "GuC last action error code: %d\n", guc.action_err);

	seq_printf(m, "GuC total action count: %llu\n", guc->action_count);

	seq_printf(m, "GuC action failure count: %u\n", guc->action_fail);

	seq_printf(m, "GuC last action command: 0x%x\n", guc->action_cmd);

	seq_printf(m, "GuC last action status: 0x%x\n", guc->action_status);

	seq_printf(m, "GuC last action error code: %d\n", guc->action_err);



	total = 0;

	seq_printf(m, "\nGuC submissions:\n");

	for_each_engine(engine, dev_priv, id) {

		u64 submissions = guc.submissions[id];

		u64 submissions = guc->submissions[id];

		total += submissions;

		seq_printf(m, "\t%-24s: %10llu, last seqno 0x%08x\n",

			engine->name, submissions, guc.last_seqno[id]);

			engine->name, submissions, guc->last_seqno[id]);

	}

	seq_printf(m, "\t%s: %llu\n", "Total", total);



	seq_printf(m, "\nGuC execbuf client @ %p:\n", guc.execbuf_client);

	i915_guc_client_info(m, dev_priv, &client);

	seq_printf(m, "\nGuC execbuf client @ %p:\n", guc->execbuf_client);

	i915_guc_client_info(m, dev_priv, guc->execbuf_client);



	i915_guc_log_info(m, dev_priv);