[Linaro-mm-sig] Re: [PATCH v6 4/4] drm/panthor: show device-wide list of DRM GEM objects over DebugFS

On Wed, Apr 09, 2025 at 10:22:22PM +0100, Adrián Larumbe wrote:

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 GEM state flags.

There's also a usage flags field for the type of BO, which tells us whether it's a kernel BO and/or mapped onto the FW's address space.

Signed-off-by: Adrián Larumbe adrian.larumbe@collabora.com

Reviewed-by: Liviu Dudau liviu.dudau@arm.com

Best regards, Liviu

---

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 | 186 +++++++++++++++++++++++ drivers/gpu/drm/panthor/panthor_gem.h | 59 +++++++ 5 files changed, 287 insertions(+)

diff --git a/drivers/gpu/drm/panthor/panthor_device.c b/drivers/gpu/drm/panthor/panthor_device.c index a9da1d1eeb70..b776e1a2e4f3 100644 --- a/drivers/gpu/drm/panthor/panthor_device.c +++ b/drivers/gpu/drm/panthor/panthor_device.c @@ -184,6 +184,11 @@ int panthor_device_init(struct panthor_device *ptdev) if (ret) return ret; +#ifdef CONFIG_DEBUG_FS

• drmm_mutex_init(&ptdev->base, &ptdev->gems.lock);
• INIT_LIST_HEAD(&ptdev->gems.node);

+#endif

• atomic_set(&ptdev->pm.state, PANTHOR_DEVICE_PM_STATE_SUSPENDED); p = alloc_page(GFP_KERNEL | __GFP_ZERO); if (!p)

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 983b24f1236c..4d3f2eb29a47 100644 --- a/drivers/gpu/drm/panthor/panthor_drv.c +++ b/drivers/gpu/drm/panthor/panthor_drv.c @@ -1535,9 +1535,35 @@ 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 3c5fc854356e..ca9baa7b43da 100644 --- a/drivers/gpu/drm/panthor/panthor_gem.c +++ b/drivers/gpu/drm/panthor/panthor_gem.c @@ -11,14 +11,51 @@ #include <drm/panthor_drm.h> #include "panthor_device.h" +#include "panthor_fw.h" #include "panthor_gem.h" #include "panthor_mmu.h" +#ifdef CONFIG_DEBUG_FS +static void panthor_gem_debugfs_bo_add(struct panthor_device *ptdev,

• 		       struct panthor_gem_object *bo)
  

+{

• INIT_LIST_HEAD(&bo->debugfs.node);
• bo->debugfs.creator.tgid = current->group_leader->pid;
• get_task_comm(bo->debugfs.creator.process_name, current->group_leader);
• mutex_lock(&ptdev->gems.lock);
• list_add_tail(&bo->debugfs.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->debugfs.node))

• return;
  

• mutex_lock(&ptdev->gems.lock);
• list_del_init(&bo->debugfs.node);
• mutex_unlock(&ptdev->gems.lock);

+}

+#else +static void panthor_gem_debugfs_bo_add(struct panthor_device *ptdev,

• 		       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);
• /*
  • Label might have been allocated with kstrdup_const(),
  • we need to take that into account when freeing the memory

@@ -87,6 +124,7 @@ panthor_kernel_bo_create(struct panthor_device *ptdev, struct panthor_vm *vm, struct drm_gem_shmem_object *obj; struct panthor_kernel_bo *kbo; struct panthor_gem_object *bo;

• u32 debug_flags = PANTHOR_DEBUGFS_GEM_USAGE_FLAG_KERNEL; int ret;

if (drm_WARN_ON(&ptdev->base, !vm)) @@ -106,7 +144,11 @@ panthor_kernel_bo_create(struct panthor_device *ptdev, struct panthor_vm *vm, kbo->obj = &obj->base; bo->flags = bo_flags;

• if (vm == panthor_fw_vm(ptdev))

• debug_flags |= PANTHOR_DEBUGFS_GEM_USAGE_FLAG_FW_MAPPED;
  

• panthor_gem_kernel_bo_set_label(kbo, name);
• panthor_gem_debugfs_bo_set_mask(to_panthor_bo(kbo->obj), debug_flags);

/* The system and GPU MMU page size might differ, which becomes a * problem for FW sections that need to be mapped at explicit address @@ -209,6 +251,8 @@ 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_add(ptdev, obj);
• return &obj->base.base;

} @@ -257,6 +301,12 @@ panthor_gem_create_with_handle(struct drm_file *file, /* drop reference from allocate - handle holds it now. */ drm_gem_object_put(&shmem->base);

• /*

• * No explicit flags are needed in the call below, since the
  

• * function internally sets the INITIALIZED bit for us.
  

• */
  

• panthor_gem_debugfs_bo_set_mask(bo, 0);
• return ret;

} @@ -288,3 +338,139 @@ panthor_gem_kernel_bo_set_label(struct panthor_kernel_bo *bo, const char *label) panthor_gem_bo_set_label(bo->obj, str); }

+#ifdef CONFIG_DEBUG_FS +static void +panthor_gem_debugfs_format_flags(char flags_str[], int flags_len,

• 		 const char * const names[], u32 name_count,
  

• 		 u32 flags)
  

+{

• bool first = true;
• int offset = 0;

+#define ACC_FLAGS(...) \

• ({ \

• offset += snprintf(flags_str + offset, flags_len - offset, ##__VA_ARGS__); \
  

• if (offset == flags_len) \
  

• 	return; \
  

• })
• ACC_FLAGS("%c", '(');
• if (!flags)

• ACC_FLAGS("%s", "none");
  

• while (flags) {

• u32 bit = fls(flags) - 1;
  

• u32 idx = bit + 1;
  

• if (!first)
  

• 	ACC_FLAGS("%s", ",");
  

• if (idx >= name_count || !names[idx])
  

• 	ACC_FLAGS("unknown-bit%d", bit);
  

• else
  

• 	ACC_FLAGS("%s", names[idx]);
  

• first = false;
  

• flags &= ~BIT(bit);
  

• }
• ACC_FLAGS("%c", ')');

+#undef ACC_FLAGS +}

+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] = {};
• size_t resident_size;
• char gem_state_str[24] = {};
• char gem_usage_str[24] = {};
• u32 gem_usage_flags = bo->debugfs.flags & (u32)~PANTHOR_DEBUGFS_GEM_USAGE_FLAG_INITIALIZED;
• u32 gem_state_flags = 0;
• static const char * const gem_state_flags_names[] = {

• [PANTHOR_DEBUGFS_GEM_STATE_FLAG_IMPORTED] = "imported",
  

• [PANTHOR_DEBUGFS_GEM_STATE_FLAG_EXPORTED] = "exported",
  

• };
• static const char * const gem_usage_flags_names[] = {

• [PANTHOR_DEBUGFS_GEM_USAGE_FLAG_KERNEL] = "kernel",
  

• [PANTHOR_DEBUGFS_GEM_USAGE_FLAG_FW_MAPPED] = "fw-mapped",
  

• };
• /* 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->debugfs.creator.process_name, bo->debugfs.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));
  

• if (bo->base.base.import_attach != NULL)

• gem_state_flags |= PANTHOR_DEBUGFS_GEM_STATE_FLAG_IMPORTED;
  

• if (bo->base.base.dma_buf != NULL)

• gem_state_flags |= PANTHOR_DEBUGFS_GEM_STATE_FLAG_EXPORTED;
  

• panthor_gem_debugfs_format_flags(gem_state_str, sizeof(gem_state_str),

• 			 gem_state_flags_names, ARRAY_SIZE(gem_state_flags_names),
  

• 			 gem_state_flags);
  

• panthor_gem_debugfs_format_flags(gem_usage_str, sizeof(gem_usage_str),

• 			 gem_usage_flags_names, ARRAY_SIZE(gem_usage_flags_names),
  

• 			 gem_usage_flags);
  

• seq_printf(m, "%-24s%-24s", gem_state_str, gem_usage_str);
• scoped_guard(mutex, &bo->label.lock) {

• seq_printf(m, "%s", bo->label.str ? : "");
  

• }
• 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 state usage label\n");
• seq_puts(m, "---------------------------------------------------------------------------------------------------------------------------------------------------------------------\n");
• scoped_guard(mutex, &ptdev->gems.lock) {

• list_for_each_entry(bo, &ptdev->gems.node, debugfs.node) {
  

• 	if (bo->debugfs.flags & PANTHOR_DEBUGFS_GEM_USAGE_FLAG_INITIALIZED)
  

• 		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 62aea06dbc6d..8c56e0c0dc9c 100644 --- a/drivers/gpu/drm/panthor/panthor_gem.h +++ b/drivers/gpu/drm/panthor/panthor_gem.h @@ -15,6 +15,48 @@ struct panthor_vm; #define PANTHOR_BO_LABEL_MAXLEN PAGE_SIZE +enum panthor_debugfs_gem_state_flags {

• /** @PANTHOR_DEBUGFS_GEM_STATE_FLAG_IMPORTED: GEM BO is PRIME imported. */
• PANTHOR_DEBUGFS_GEM_STATE_FLAG_IMPORTED = BIT(0),
• /** @PANTHOR_DEBUGFS_GEM_STATE_FLAG_EXPORTED: GEM BO is PRIME exported. */
• PANTHOR_DEBUGFS_GEM_STATE_FLAG_EXPORTED = BIT(1),

+};

+enum panthor_debugfs_gem_usage_flags {

• /** @PANTHOR_DEBUGFS_GEM_USAGE_FLAG_KERNEL: BO is for kernel use only. */
• PANTHOR_DEBUGFS_GEM_USAGE_FLAG_KERNEL = BIT(0),
• /** @PANTHOR_DEBUGFS_GEM_USAGE_FLAG_FW_MAPPED: BO is mapped on the FW VM. */
• PANTHOR_DEBUGFS_GEM_USAGE_FLAG_FW_MAPPED = BIT(1),
• /** @PANTHOR_DEBUGFS_GEM_USAGE_FLAG_INITIALIZED: BO is ready for DebugFS display. */
• PANTHOR_DEBUGFS_GEM_USAGE_FLAG_INITIALIZED = BIT(31),

+};

+/**

• • 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;
• /** @flags: Combination of panthor_debugfs_gem_usage_flags flags */
• u32 flags;

+};

/**

• struct panthor_gem_object - Driver specific GEM object.

*/ @@ -62,6 +104,10 @@ 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 debugfs;

+#endif }; /** @@ -157,4 +203,17 @@ 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);
  

+static inline void +panthor_gem_debugfs_bo_set_mask(struct panthor_gem_object *bo, u32 type_mask) +{

• bo->debugfs.flags = type_mask | PANTHOR_DEBUGFS_GEM_USAGE_FLAG_INITIALIZED;

+}

+#else +void panthor_gem_debugfs_bo_set_mask(struct panthor_gem_object *bo, u32 type_mask) {}; +#endif

#endif /* __PANTHOR_GEM_H__ */

2.48.1