Add a device DebugFS file that displays a complete list of all the DRM GEM
objects that are exposed to UM through a DRM handle.

Since leaking object identifiers that might belong to a different NS is
inadmissible, this functionality is only made available in debug builds
with DEBUGFS support enabled.

File format is that of a table, with each entry displaying a variety of
fields with information about each GEM object.

Each GEM object entry in the file displays the following information
fields: Client PID, BO's global name, reference count, BO virtual size, BO
resize size, VM address in its DRM-managed range, BO label and a flag
bitmask.

Signed-off-by: Adrián Larumbe <adrian.laru...@collabora.com>
---
 drivers/gpu/drm/panthor/panthor_device.c |   5 +
 drivers/gpu/drm/panthor/panthor_device.h |  11 ++
 drivers/gpu/drm/panthor/panthor_drv.c    |  26 +++++
 drivers/gpu/drm/panthor/panthor_gem.c    | 130 +++++++++++++++++++++++
 drivers/gpu/drm/panthor/panthor_gem.h    |  29 +++++
 5 files changed, 201 insertions(+)

diff --git a/drivers/gpu/drm/panthor/panthor_device.c 
b/drivers/gpu/drm/panthor/panthor_device.c
index a9da1d1eeb70..bae1a74d7111 100644
--- a/drivers/gpu/drm/panthor/panthor_device.c
+++ b/drivers/gpu/drm/panthor/panthor_device.c
@@ -263,6 +263,11 @@ int panthor_device_init(struct panthor_device *ptdev)
        pm_runtime_set_autosuspend_delay(ptdev->base.dev, 50);
        pm_runtime_use_autosuspend(ptdev->base.dev);
 
+#ifdef CONFIG_DEBUG_FS
+       drmm_mutex_init(&ptdev->base, &ptdev->gems.lock);
+       INIT_LIST_HEAD(&ptdev->gems.node);
+#endif
+
        ret = drm_dev_register(&ptdev->base, 0);
        if (ret)
                goto err_disable_autosuspend;
diff --git a/drivers/gpu/drm/panthor/panthor_device.h 
b/drivers/gpu/drm/panthor/panthor_device.h
index da6574021664..86206a961b38 100644
--- a/drivers/gpu/drm/panthor/panthor_device.h
+++ b/drivers/gpu/drm/panthor/panthor_device.h
@@ -205,6 +205,17 @@ struct panthor_device {
 
        /** @fast_rate: Maximum device clock frequency. Set by DVFS */
        unsigned long fast_rate;
+
+#ifdef CONFIG_DEBUG_FS
+       /** @gems: Device-wide list of GEM objects owned by at least one file. 
*/
+       struct {
+               /** @gems.lock: Protects the device-wide list of GEM objects. */
+               struct mutex lock;
+
+               /** @node: Used to keep track of all the device's DRM objects */
+               struct list_head node;
+       } gems;
+#endif
 };
 
 struct panthor_gpu_usage {
diff --git a/drivers/gpu/drm/panthor/panthor_drv.c 
b/drivers/gpu/drm/panthor/panthor_drv.c
index e91acf132e06..61ebf87f2946 100644
--- a/drivers/gpu/drm/panthor/panthor_drv.c
+++ b/drivers/gpu/drm/panthor/panthor_drv.c
@@ -1531,9 +1531,35 @@ static const struct file_operations 
panthor_drm_driver_fops = {
 };
 
 #ifdef CONFIG_DEBUG_FS
+static int panthor_gems_show(struct seq_file *m, void *data)
+{
+       struct drm_info_node *node = m->private;
+       struct drm_device *dev = node->minor->dev;
+       struct panthor_device *ptdev = container_of(dev, struct panthor_device, 
base);
+
+       panthor_gem_debugfs_print_bos(ptdev, m);
+
+       return 0;
+}
+
+
+static struct drm_info_list panthor_debugfs_list[] = {
+       {"gems", panthor_gems_show, 0, NULL},
+};
+
+static int panthor_gems_debugfs_init(struct drm_minor *minor)
+{
+       drm_debugfs_create_files(panthor_debugfs_list,
+                                ARRAY_SIZE(panthor_debugfs_list),
+                                minor->debugfs_root, minor);
+
+       return 0;
+}
+
 static void panthor_debugfs_init(struct drm_minor *minor)
 {
        panthor_mmu_debugfs_init(minor);
+       panthor_gems_debugfs_init(minor);
 }
 #endif
 
diff --git a/drivers/gpu/drm/panthor/panthor_gem.c 
b/drivers/gpu/drm/panthor/panthor_gem.c
index 165c7f4eb920..f7eb413d88e7 100644
--- a/drivers/gpu/drm/panthor/panthor_gem.c
+++ b/drivers/gpu/drm/panthor/panthor_gem.c
@@ -2,6 +2,7 @@
 /* Copyright 2019 Linaro, Ltd, Rob Herring <r...@kernel.org> */
 /* Copyright 2023 Collabora ltd. */
 
+#include <linux/cleanup.h>
 #include <linux/dma-buf.h>
 #include <linux/dma-mapping.h>
 #include <linux/err.h>
@@ -13,11 +14,49 @@
 #include "panthor_gem.h"
 #include "panthor_mmu.h"
 
+#ifdef CONFIG_DEBUG_FS
+static void panthor_gem_debugfs_bo_init(struct panthor_gem_object *bo)
+{
+       INIT_LIST_HEAD(&bo->gems.node);
+       bo->gems.creator.tgid = current->group_leader->pid;
+       get_task_comm(bo->gems.creator.process_name, current->group_leader);
+}
+
+static void panthor_gem_debugfs_bo_add(struct panthor_gem_object *bo)
+{
+       struct panthor_device *ptdev =  container_of(bo->base.base.dev,
+                                                    struct panthor_device, 
base);
+
+       mutex_lock(&ptdev->gems.lock);
+       list_add_tail(&bo->gems.node, &ptdev->gems.node);
+       mutex_unlock(&ptdev->gems.lock);
+}
+
+static void panthor_gem_debugfs_bo_rm(struct panthor_gem_object *bo)
+{
+       struct panthor_device *ptdev = container_of(bo->base.base.dev,
+                                                   struct panthor_device, 
base);
+
+       if (list_empty(&bo->gems.node))
+               return;
+
+       mutex_lock(&ptdev->gems.lock);
+       list_del_init(&bo->gems.node);
+       mutex_unlock(&ptdev->gems.lock);
+}
+#else
+static void panthor_gem_debugfs_bo_init(struct panthor_gem_object *bo) {}
+static void panthor_gem_debugfs_bo_add(struct panthor_gem_object *bo) {}
+static void panthor_gem_debugfs_bo_rm(struct panthor_gem_object *bo) {}
+#endif
+
 static void panthor_gem_free_object(struct drm_gem_object *obj)
 {
        struct panthor_gem_object *bo = to_panthor_bo(obj);
        struct drm_gem_object *vm_root_gem = bo->exclusive_vm_root_gem;
 
+       panthor_gem_debugfs_bo_rm(bo);
+
        kfree(bo->label.str);
        mutex_destroy(&bo->label.lock);
 
@@ -201,6 +240,8 @@ struct drm_gem_object *panthor_gem_create_object(struct 
drm_device *ddev, size_t
        drm_gem_gpuva_set_lock(&obj->base.base, &obj->gpuva_list_lock);
        mutex_init(&obj->label.lock);
 
+       panthor_gem_debugfs_bo_init(obj);
+
        return &obj->base.base;
 }
 
@@ -249,6 +290,8 @@ panthor_gem_create_with_handle(struct drm_file *file,
        /* drop reference from allocate - handle holds it now. */
        drm_gem_object_put(&shmem->base);
 
+       panthor_gem_debugfs_bo_add(bo);
+
        return ret;
 }
 
@@ -271,3 +314,90 @@ panthor_gem_kernel_bo_set_label(struct panthor_kernel_bo 
*bo, const char *label)
 {
        panthor_gem_bo_set_label(bo->obj, kstrdup_const(label, GFP_KERNEL));
 }
+
+#ifdef CONFIG_DEBUG_FS
+static bool panfrost_gem_print_flag(const char *name,
+                                   bool is_set,
+                                   bool other_flags_printed,
+                                   struct seq_file *m)
+{
+       if (is_set)
+               seq_printf(m, "%s%s", other_flags_printed ? "," : "", name);
+
+       return is_set | other_flags_printed;
+}
+
+struct gem_size_totals {
+       size_t size;
+       size_t resident;
+       size_t reclaimable;
+};
+
+static void panthor_gem_debugfs_bo_print(struct panthor_gem_object *bo,
+                                        struct seq_file *m,
+                                        struct gem_size_totals *totals)
+{
+       unsigned int refcount = kref_read(&bo->base.base.refcount);
+       char creator_info[32] = {};
+       bool has_flags = false;
+       size_t resident_size;
+
+       /* Skip BOs being destroyed. */
+       if (!refcount)
+               return;
+
+       resident_size = bo->base.pages != NULL ? bo->base.base.size : 0;
+
+       snprintf(creator_info, sizeof(creator_info),
+                "%s/%d", bo->gems.creator.process_name, bo->gems.creator.tgid);
+       seq_printf(m, "%-32s%-16d%-16d%-16zd%-16zd%-16lx",
+                  creator_info,
+                  bo->base.base.name,
+                  refcount,
+                  bo->base.base.size,
+                  resident_size,
+                  drm_vma_node_start(&bo->base.base.vma_node));
+
+       seq_puts(m, "(");
+       has_flags = panfrost_gem_print_flag("imported", 
bo->base.base.import_attach != NULL,
+                                           has_flags, m);
+       has_flags = panfrost_gem_print_flag("exported", bo->base.base.dma_buf 
!= NULL,
+                                           has_flags, m);
+       if (bo->base.madv < 0)
+               has_flags = panfrost_gem_print_flag("purged", true, has_flags, 
m);
+       else if (bo->base.madv > 0)
+               has_flags = panfrost_gem_print_flag("purgeable", true, 
has_flags, m);
+       if (!has_flags)
+               seq_puts(m, "none");
+       seq_puts(m, ")");
+
+       mutex_lock(&bo->label.lock);
+       seq_printf(m, "%-16s%-60s", "", bo->label.str ? : NULL);
+       mutex_unlock(&bo->label.lock);
+       seq_puts(m, "\n");
+
+       totals->size += bo->base.base.size;
+       totals->resident += resident_size;
+       if (bo->base.madv > 0)
+               totals->reclaimable += resident_size;
+}
+
+void panthor_gem_debugfs_print_bos(struct panthor_device *ptdev,
+                                  struct seq_file *m)
+{
+       struct gem_size_totals totals = {0};
+       struct panthor_gem_object *bo;
+
+       seq_puts(m, "created-by                      global-name     refcount   
     size            resident-size   file-offset     flags           label\n");
+       seq_puts(m, 
"------------------------------------------------------------------------------------------------------------------------------------------------\n");
+
+       scoped_guard(mutex, &ptdev->gems.lock) {
+               list_for_each_entry(bo, &ptdev->gems.node, gems.node)
+                       panthor_gem_debugfs_bo_print(bo, m, &totals);
+       }
+
+       seq_puts(m, 
"================================================================================================================================================\n");
+       seq_printf(m, "Total size: %zd, Total resident: %zd, Total reclaimable: 
%zd\n",
+                  totals.size, totals.resident, totals.reclaimable);
+}
+#endif
diff --git a/drivers/gpu/drm/panthor/panthor_gem.h 
b/drivers/gpu/drm/panthor/panthor_gem.h
index 0582826b341a..7c896ec35801 100644
--- a/drivers/gpu/drm/panthor/panthor_gem.h
+++ b/drivers/gpu/drm/panthor/panthor_gem.h
@@ -13,6 +13,26 @@
 
 struct panthor_vm;
 
+/**
+ * struct panthor_gem_debugfs - GEM object's DebugFS list information
+ */
+struct panthor_gem_debugfs {
+       /**
+        * @node: Node used to insert the object in the device-wide list of
+        * GEM objects, to display information about it through a DebugFS file.
+        */
+       struct list_head node;
+
+       /** @creator: Information about the UM process which created the GEM. */
+       struct {
+               /** @creator.process_name: Group leader name in owning thread's 
process */
+               char process_name[TASK_COMM_LEN];
+
+               /** @creator.tgid: PID of the thread's group leader within its 
process */
+               pid_t tgid;
+       } creator;
+};
+
 /**
  * struct panthor_gem_object - Driver specific GEM object.
  */
@@ -60,6 +80,10 @@ struct panthor_gem_object {
                /** @lock.str: Protects access to the @label.str field. */
                struct mutex lock;
        } label;
+
+#ifdef CONFIG_DEBUG_FS
+       struct panthor_gem_debugfs gems;
+#endif
 };
 
 /**
@@ -155,4 +179,9 @@ panthor_kernel_bo_create(struct panthor_device *ptdev, 
struct panthor_vm *vm,
 
 void panthor_kernel_bo_destroy(struct panthor_kernel_bo *bo);
 
+#ifdef CONFIG_DEBUG_FS
+void panthor_gem_debugfs_print_bos(struct panthor_device *pfdev,
+                                  struct seq_file *m);
+#endif
+
 #endif /* __PANTHOR_GEM_H__ */
-- 
2.48.1

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