Re: [PATCH v4 7/7] drm/panthor: Expose the panthor perf ioctls

[Lukas Zapolskas <lukas.zapolskas@arm.com>]

On 18/07/2025 16:19, Adrián Larumbe wrote:
> Hi Lucas, another missing remark from the original review,
> 
> On 16.05.2025 16:49, Lukas Zapolskas wrote:
>> This patch implements the PANTHOR_PERF_CONTROL ioctl series, and
>> a PANTHOR_GET_UOBJ wrapper to deal with the backwards and forwards
>> compatibility of the uAPI.
>>
>> The minor version is bumped to indicate that the feature is now
>> supported.
>>
>> Signed-off-by: Lukas Zapolskas <lukas.zapolskas@arm.com>
>> Reviewed-by: Adrián Larumbe <adrian.larumbe@collabora.com>
>> ---
>>  drivers/gpu/drm/panthor/panthor_drv.c | 141 +++++++++++++++++++++++++-
>>  1 file changed, 139 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/panthor/panthor_drv.c b/drivers/gpu/drm/panthor/panthor_drv.c
>> index 4c1381320859..850a894fe91b 100644
>> --- a/drivers/gpu/drm/panthor/panthor_drv.c
>> +++ b/drivers/gpu/drm/panthor/panthor_drv.c
>> @@ -31,6 +31,7 @@
>>  #include "panthor_gpu.h"
>>  #include "panthor_heap.h"
>>  #include "panthor_mmu.h"
>> +#include "panthor_perf.h"
>>  #include "panthor_regs.h"
>>  #include "panthor_sched.h"
>>
>> @@ -73,6 +74,39 @@ panthor_set_uobj(u64 usr_ptr, u32 usr_size, u32 min_size, u32 kern_size, const v
>>  	return 0;
>>  }
>>
>> +/**
>> + * panthor_get_uobj() - Copy kernel object to user object.
>> + * @usr_ptr: Users pointer.
>> + * @usr_size: Size of the user object.
>> + * @min_size: Minimum size for this object.
>> + *
>> + * Helper automating kernel -> user object copies.
>> + *
>> + * Don't use this function directly, use PANTHOR_UOBJ_GET() instead.
>> + *
>> + * Return: valid pointer on success, an encoded error code otherwise.
>> + */
>> +static void*
>> +panthor_get_uobj(u64 usr_ptr, u32 usr_size, u32 min_size)
>> +{
>> +	int ret;
>> +	void *out_alloc __free(kvfree) = NULL;
>> +
>> +	/* User size shouldn't be smaller than the minimal object size. */
>> +	if (usr_size < min_size)
>> +		return ERR_PTR(-EINVAL);
>> +
>> +	out_alloc = kvmalloc(min_size, GFP_KERNEL);
>> +	if (!out_alloc)
>> +		return ERR_PTR(-ENOMEM);
>> +
>> +	ret = copy_struct_from_user(out_alloc, min_size, u64_to_user_ptr(usr_ptr), usr_size);
>> +	if (ret)
>> +		return ERR_PTR(ret);
>> +
>> +	return_ptr(out_alloc);
>> +}
>> +
>>  /**
>>   * panthor_get_uobj_array() - Copy a user object array into a kernel accessible object array.
>>   * @in: The object array to copy.
>> @@ -176,7 +210,12 @@ panthor_get_uobj_array(const struct drm_panthor_obj_array *in, u32 min_stride,
>>  		 PANTHOR_UOBJ_DECL(struct drm_panthor_queue_submit, syncs), \
>>  		 PANTHOR_UOBJ_DECL(struct drm_panthor_queue_create, ringbuf_size), \
>>  		 PANTHOR_UOBJ_DECL(struct drm_panthor_vm_bind_op, syncs), \
>> -		 PANTHOR_UOBJ_DECL(struct drm_panthor_perf_info, shader_blocks))
>> +		 PANTHOR_UOBJ_DECL(struct drm_panthor_perf_info, shader_blocks), \
>> +		 PANTHOR_UOBJ_DECL(struct drm_panthor_perf_cmd_setup, shader_enable_mask), \
>> +		 PANTHOR_UOBJ_DECL(struct drm_panthor_perf_cmd_start, user_data), \
>> +		 PANTHOR_UOBJ_DECL(struct drm_panthor_perf_cmd_stop, user_data), \
>> +		 PANTHOR_UOBJ_DECL(struct drm_panthor_perf_cmd_sample, user_data))
>> +
>>
>>  /**
>>   * PANTHOR_UOBJ_SET() - Copy a kernel object to a user object.
>> @@ -191,6 +230,24 @@ panthor_get_uobj_array(const struct drm_panthor_obj_array *in, u32 min_stride,
>>  			 PANTHOR_UOBJ_MIN_SIZE(_src_obj), \
>>  			 sizeof(_src_obj), &(_src_obj))
>>
>> +/**
>> + * PANTHOR_UOBJ_GET() - Copies a user object from _usr_ptr to a kernel accessible _dest_ptr.
>> + * @_dest_ptr: Local variable
>> + * @_usr_size: Size of the user object.
>> + * @_usr_ptr: The pointer of the object in userspace.
>> + *
>> + * Return: Error code. See panthor_get_uobj().
>> + */
>> +#define PANTHOR_UOBJ_GET(_dest_ptr, _usr_size, _usr_ptr) \
>> +	({ \
>> +		typeof(_dest_ptr) _tmp; \
>> +		_tmp = panthor_get_uobj(_usr_ptr, _usr_size, \
>> +				PANTHOR_UOBJ_MIN_SIZE(_tmp[0])); \
>> +		if (!IS_ERR(_tmp)) \
>> +			_dest_ptr = _tmp; \
>> +		PTR_ERR_OR_ZERO(_tmp); \
>> +	})
>> +
>>  /**
>>   * PANTHOR_UOBJ_GET_ARRAY() - Copy a user object array to a kernel accessible
>>   * object array.
>> @@ -1339,6 +1396,83 @@ static int panthor_ioctl_vm_get_state(struct drm_device *ddev, void *data,
>>  	return 0;
>>  }
>>
>> +#define perf_cmd(command) \
>> +	({ \
>> +		struct drm_panthor_perf_cmd_##command *command##_args __free(kvfree) = NULL; \
>> +		int _ret = PANTHOR_UOBJ_GET(command##_args, args->size, args->pointer); \
>> +		if (_ret) \
>> +			return _ret; \
>> +		return panthor_perf_session_##command(pfile, ptdev->perf, args->handle, \
>> +				command##_args->user_data); \
>> +	})
>> +
>> +static int panthor_ioctl_perf_control(struct drm_device *ddev, void *data,
>> +				      struct drm_file *file)
>> +{
>> +	struct panthor_device *ptdev = container_of(ddev, struct panthor_device, base);
>> +	struct panthor_file *pfile = file->driver_priv;
>> +	struct drm_panthor_perf_control *args = data;
>> +	int ret;
>> +
>> +	if (!args->pointer) {
>> +		switch (args->cmd) {
>> +		case DRM_PANTHOR_PERF_COMMAND_SETUP:
>> +			args->size = sizeof(struct drm_panthor_perf_cmd_setup);
>> +			return 0;
>> +
>> +		case DRM_PANTHOR_PERF_COMMAND_TEARDOWN:
>> +			args->size = 0;
>> +			return 0;
>> +
>> +		case DRM_PANTHOR_PERF_COMMAND_START:
>> +			args->size = sizeof(struct drm_panthor_perf_cmd_start);
>> +			return 0;
>> +
>> +		case DRM_PANTHOR_PERF_COMMAND_STOP:
>> +			args->size = sizeof(struct drm_panthor_perf_cmd_stop);
>> +			return 0;
>> +
>> +		case DRM_PANTHOR_PERF_COMMAND_SAMPLE:
>> +			args->size = sizeof(struct drm_panthor_perf_cmd_sample);
>> +			return 0;
>> +
>> +		default:
>> +			return -EINVAL;
>> +		}
>> +	}
>> +
>> +	switch (args->cmd) {
>> +	case DRM_PANTHOR_PERF_COMMAND_SETUP:
>> +	{
>> +		struct drm_panthor_perf_cmd_setup *setup_args __free(kvfree) = NULL;
>> +
>> +		ret = PANTHOR_UOBJ_GET(setup_args, args->size, args->pointer);
>> +		if (ret)
>> +			return -EINVAL;
>> +
>> +		return panthor_perf_session_setup(ptdev, ptdev->perf, setup_args, pfile);
> 
> I think this is something I had already brought up in the revision for v2 of the patch series,
> but I think I would pass the drm_file here straight away rather than the panthor file,
> then retrieve the panthor_file pointer from the file's driver_priv field inside
> panthor_perf_session_setup, and that way you can get rid of struct panthor_file::drm_file.
> 
> I think this should be alright, because the only place where it'd be essential to keep
> a copy of the drm_file is in the session struct, to make sure sessions match their DRM device fd's.
> 

Thank you for pointing this out, I hadn't quite understood the suggestion for v2. Will update 
the patches accordingly. 

>> +	}
>> +	case DRM_PANTHOR_PERF_COMMAND_TEARDOWN:
>> +	{
>> +		return panthor_perf_session_teardown(pfile, ptdev->perf, args->handle);
>> +	}
>> +	case DRM_PANTHOR_PERF_COMMAND_START:
>> +	{
>> +		perf_cmd(start);
>> +	}
>> +	case DRM_PANTHOR_PERF_COMMAND_STOP:
>> +	{
>> +		perf_cmd(stop);
>> +	}
>> +	case DRM_PANTHOR_PERF_COMMAND_SAMPLE:
>> +	{
>> +		perf_cmd(sample);
>> +	}
>> +	default:
>> +		return -EINVAL;
>> +	}
>> +}
>> +
>>  static int
>>  panthor_open(struct drm_device *ddev, struct drm_file *file)
>>  {
>> @@ -1409,6 +1543,7 @@ static const struct drm_ioctl_desc panthor_drm_driver_ioctls[] = {
>>  	PANTHOR_IOCTL(TILER_HEAP_CREATE, tiler_heap_create, DRM_RENDER_ALLOW),
>>  	PANTHOR_IOCTL(TILER_HEAP_DESTROY, tiler_heap_destroy, DRM_RENDER_ALLOW),
>>  	PANTHOR_IOCTL(GROUP_SUBMIT, group_submit, DRM_RENDER_ALLOW),
>> +	PANTHOR_IOCTL(PERF_CONTROL, perf_control, DRM_RENDER_ALLOW),
>>  };
>>
>>  static int panthor_mmap(struct file *filp, struct vm_area_struct *vma)
>> @@ -1518,6 +1653,8 @@ static void panthor_debugfs_init(struct drm_minor *minor)
>>   * - 1.2 - adds DEV_QUERY_GROUP_PRIORITIES_INFO query
>>   *       - adds PANTHOR_GROUP_PRIORITY_REALTIME priority
>>   * - 1.3 - adds DRM_PANTHOR_GROUP_STATE_INNOCENT flag
>> + * - 1.4 - adds DEV_QUERY_PERF_INFO query
>> + *       - adds PERF_CONTROL ioctl
>>   */
>>  static const struct drm_driver panthor_drm_driver = {
>>  	.driver_features = DRIVER_RENDER | DRIVER_GEM | DRIVER_SYNCOBJ |
>> @@ -1531,7 +1668,7 @@ static const struct drm_driver panthor_drm_driver = {
>>  	.name = "panthor",
>>  	.desc = "Panthor DRM driver",
>>  	.major = 1,
>> -	.minor = 3,
>> +	.minor = 4,
>>
>>  	.gem_create_object = panthor_gem_create_object,
>>  	.gem_prime_import_sg_table = drm_gem_shmem_prime_import_sg_table,
>> --
>> 2.33.0.dirty
> 
> 
> Adrian Larumbe