[Linaro-mm-sig] Re: [PATCH 8/8] drm/panthor: Expose protected rendering features

On Tue, 5 May 2026 16:05:14 +0200 Ketil Johnsen ketil.johnsen@arm.com wrote:

Add query for protected rendering capability. Add flag to group creation to specify need for protected rendering. Bump panthor version number.

Signed-off-by: Ketil Johnsen ketil.johnsen@arm.com

drivers/gpu/drm/panthor/panthor_drv.c | 21 +++++++++++- drivers/gpu/drm/panthor/panthor_sched.c | 21 +++++++----- include/uapi/drm/panthor_drm.h | 45 +++++++++++++++++++++++-- 3 files changed, 76 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/panthor/panthor_drv.c b/drivers/gpu/drm/panthor/panthor_drv.c index 73fc983dc9b44..817df17f31f15 100644 --- a/drivers/gpu/drm/panthor/panthor_drv.c +++ b/drivers/gpu/drm/panthor/panthor_drv.c @@ -177,6 +177,7 @@ panthor_get_uobj_array(const struct drm_panthor_obj_array *in, u32 min_stride, PANTHOR_UOBJ_DECL(struct drm_panthor_csif_info, pad), \ PANTHOR_UOBJ_DECL(struct drm_panthor_timestamp_info, current_timestamp), \ PANTHOR_UOBJ_DECL(struct drm_panthor_group_priorities_info, pad), \

•  PANTHOR_UOBJ_DECL(struct drm_panthor_protected_info, features), \
  

  PANTHOR_UOBJ_DECL(struct drm_panthor_sync_op, timeline_value), \ PANTHOR_UOBJ_DECL(struct drm_panthor_queue_submit, syncs), \ PANTHOR_UOBJ_DECL(struct drm_panthor_queue_create, ringbuf_size), \

@@ -928,12 +929,20 @@ static void panthor_query_group_priorities_info(struct drm_file *file, } } +static void panthor_query_protected_info(struct panthor_device *ptdev,

• 			 struct drm_panthor_protected_info *arg)
  

+{

• arg->features =

• ptdev->protm.heap ? DRM_PANTHOR_PROTECTED_FEATURE_BASIC : 0;
  

+}

static int panthor_ioctl_dev_query(struct drm_device *ddev, void *data, struct drm_file *file) { struct panthor_device *ptdev = container_of(ddev, struct panthor_device, base); struct drm_panthor_dev_query *args = data; struct drm_panthor_timestamp_info timestamp_info; struct drm_panthor_group_priorities_info priorities_info;

• struct drm_panthor_protected_info protected_info; int ret;

if (!args->pointer) { @@ -954,6 +963,10 @@ static int panthor_ioctl_dev_query(struct drm_device *ddev, void *data, struct d args->size = sizeof(priorities_info); return 0;

• case DRM_PANTHOR_DEV_QUERY_PROTECTED_INFO:
  

• 	args->size = sizeof(protected_info);
  

• 	return 0;
  

• default: return -EINVAL; }

@@ -984,6 +997,11 @@ static int panthor_ioctl_dev_query(struct drm_device *ddev, void *data, struct d panthor_query_group_priorities_info(file, &priorities_info); return PANTHOR_UOBJ_SET(args->pointer, args->size, priorities_info);

• case DRM_PANTHOR_DEV_QUERY_PROTECTED_INFO:

• panthor_query_protected_info(ptdev, &protected_info);
  

• return PANTHOR_UOBJ_SET(args->pointer, args->size,
  

• 			protected_info);
  

• default: return -EINVAL; }

@@ -1779,6 +1797,7 @@ static void panthor_debugfs_init(struct drm_minor *minor)

•   - adds DRM_IOCTL_PANTHOR_BO_QUERY_INFO ioctl
  

•   - adds drm_panthor_gpu_info::selected_coherency
  

• • 1.8 - extends DEV_QUERY_TIMESTAMP_INFO with flags

• • • 1.9 - adds DEV_QUERY_PROTECTED_INFO query

It's adding more than just DEV_QUERY_PROTECTED_INFO (it also adds a new flags field to group_create and a flag that tells that the group intends to use protected mode).

*/ static const struct drm_driver panthor_drm_driver = { .driver_features = DRIVER_RENDER | DRIVER_GEM | DRIVER_SYNCOBJ | @@ -1792,7 +1811,7 @@ static const struct drm_driver panthor_drm_driver = { .name = "panthor", .desc = "Panthor DRM driver", .major = 1,

• .minor = 8,

• .minor = 9,

.gem_prime_import_sg_table = panthor_gem_prime_import_sg_table, .gem_prime_import = panthor_gem_prime_import, diff --git a/drivers/gpu/drm/panthor/panthor_sched.c b/drivers/gpu/drm/panthor/panthor_sched.c index acb04250c7def..0e8a1059de589 100644 --- a/drivers/gpu/drm/panthor/panthor_sched.c +++ b/drivers/gpu/drm/panthor/panthor_sched.c @@ -3868,6 +3868,7 @@ static void add_group_kbo_sizes(struct panthor_device *ptdev, } #define MAX_GROUPS_PER_POOL 128 +#define GROUP_CREATE_FLAGS DRM_PANTHOR_GROUP_CREATE_PROTECTED int panthor_group_create(struct panthor_file *pfile, const struct drm_panthor_group_create *group_args, @@ -3882,10 +3883,10 @@ int panthor_group_create(struct panthor_file *pfile, u32 gid, i, suspend_size; int ret;

• if (group_args->pad)

• if (group_args->priority >= PANTHOR_CSG_PRIORITY_COUNT) return -EINVAL;

• if (group_args->priority >= PANTHOR_CSG_PRIORITY_COUNT)

• if (group_args->flags & ~GROUP_CREATE_FLAGS) return -EINVAL;

if ((group_args->compute_core_mask & ~ptdev->gpu_info.shader_present) || @@ -3937,12 +3938,16 @@ int panthor_group_create(struct panthor_file *pfile, goto err_put_group; }

• suspend_size = csg_iface->control->protm_suspend_size;
• group->protm_suspend_buf = panthor_fw_alloc_protm_suspend_buf_mem(ptdev, suspend_size);
• if (IS_ERR(group->protm_suspend_buf)) {

• ret = PTR_ERR(group->protm_suspend_buf);
  

• group->protm_suspend_buf = NULL;
  

• goto err_put_group;
  

• if (group_args->flags & DRM_PANTHOR_GROUP_CREATE_PROTECTED) {

• suspend_size = csg_iface->control->protm_suspend_size;
  

• group->protm_suspend_buf =
  

• 	panthor_fw_alloc_protm_suspend_buf_mem(ptdev,
  

• 					       suspend_size);
  

• if (IS_ERR(group->protm_suspend_buf)) {
  

• 	ret = PTR_ERR(group->protm_suspend_buf);
  

• 	group->protm_suspend_buf = NULL;
  

• 	goto err_put_group;
  

• }
  

  }

group->syncobjs = panthor_kernel_bo_create(ptdev, group->vm, diff --git a/include/uapi/drm/panthor_drm.h b/include/uapi/drm/panthor_drm.h index 0e455d91e77d4..914110003bcd1 100644 --- a/include/uapi/drm/panthor_drm.h +++ b/include/uapi/drm/panthor_drm.h @@ -253,6 +253,11 @@ enum drm_panthor_dev_query_type { * @DRM_PANTHOR_DEV_QUERY_GROUP_PRIORITIES_INFO: Query allowed group priorities information. */ DRM_PANTHOR_DEV_QUERY_GROUP_PRIORITIES_INFO,

• /**

• * @DRM_PANTHOR_DEV_QUERY_PROTECTED_INFO: Query supported protected rendering information.
  

• */
  

• DRM_PANTHOR_DEV_QUERY_PROTECTED_INFO,

}; /** @@ -504,6 +509,28 @@ struct drm_panthor_group_priorities_info { __u8 pad[3]; }; +/**

• • enum drm_panthor_protected_feature_flags - Supported protected rendering features

Protected rendering is a bit vague, especially since it's usually referred as protected memory/content in graphics APIs. Maybe we should have a short paragraph explaining what we mean by that (access of protected memory from the GPU).

• • Place new types at the end, don't re-order, don't remove or replace.
• */

+enum drm_panthor_protected_feature_flags {

• /** @DRM_PANTHOR_PROTECTED_FEATURE_BASIC: Protected rendering available */
• DRM_PANTHOR_PROTECTED_FEATURE_BASIC = 1 << 0,

I'm not a huge fan of this _BASIC specifier, since it doesn't tell much about the actual implementation, and what the UMD has to do to access protected memory from the GPU. Given the feature/CS-instruction is named _PROTM, I'd go for

/** * @DRM_PANTHOR_PROTECTED_FEATURE_PROTM: Protected memory access * based on PROTM CS instructions * * This is currently the only option to access protected * memory from the GPU. Other modes or advanced features might * be added at some point. */ DRM_PANTHOR_PROTECTED_FEATURE_PROTM = 1 << 0,

+};

+/**

• • struct drm_panthor_protected_info - protected support information
• • Structure grouping all queryable information relating to the allowed group priorities.
• */

+struct drm_panthor_protected_info {

• /**

• * @features: Combination of enum drm_panthor_protected_feature_flags flags.
  

• */
  

• __u32 features;

+};

/**

• struct drm_panthor_dev_query - Arguments passed to DRM_PANTHOR_IOCTL_DEV_QUERY

*/ @@ -843,6 +870,18 @@ enum drm_panthor_group_priority { PANTHOR_GROUP_PRIORITY_REALTIME, }; +/**

• • enum drm_panthor_group_create_flags - Group create flags
• */

+enum drm_panthor_group_create_flags {

s/drm_panthor_group_create_flags/drm_panthor_group_feature_flags/

• /**

• * @DRM_PANTHOR_GROUP_CREATE_PROTECTED: Support protected mode
  

• *
  

• * Enable protected rendering work to be executed on this group.
  

• */
  

• DRM_PANTHOR_GROUP_CREATE_PROTECTED = 1 << 0,

I'd go directly DRM_PANTHOR_GROUP_FEATURE_PROTM, since this is the instruction the group will use to enter protected mode. If we ever have multiple ways to do protected rendering, I guess it would materialize as a different flag, allowing the KMD to know exactly the way protected rendering is going to be done.

+};

/**

• struct drm_panthor_group_create - Arguments passed to DRM_IOCTL_PANTHOR_GROUP_CREATE

*/ @@ -877,8 +916,10 @@ struct drm_panthor_group_create { /** @priority: Group priority (see enum drm_panthor_group_priority). */ __u8 priority;

• /** @pad: Padding field, MBZ. */
• __u32 pad;

• /**

• * @flags: Flags. Must be a combination of drm_panthor_group_create_flags flags.
  

• */
  

• __u32 flags;

/** * @compute_core_mask: Mask encoding cores that can be used for compute jobs.