Re: [PATCH 6/9] dma-buf: heaps: mtk_sec_heap: Add tee service call for buffer allocating/freeing

[Vijayanand Jitta]

On 9/11/2023 8:00 AM, Yong Wu wrote:
> Add TEE service call for secure memory allocating/freeing.
> 
> Signed-off-by: Anan Sun <anan.sun@xxxxxxxxxxxx>
> Signed-off-by: Yong Wu <yong.wu@xxxxxxxxxxxx>
> ---
>  drivers/dma-buf/heaps/mtk_secure_heap.c | 69 ++++++++++++++++++++++++-
>  1 file changed, 68 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/dma-buf/heaps/mtk_secure_heap.c b/drivers/dma-buf/heaps/mtk_secure_heap.c
> index e3da33a3d083..14c2a16a7164 100644
> --- a/drivers/dma-buf/heaps/mtk_secure_heap.c
> +++ b/drivers/dma-buf/heaps/mtk_secure_heap.c
> @@ -17,6 +17,9 @@
>  
>  #define MTK_TEE_PARAM_NUM		4
>  
> +#define TZCMD_MEM_SECURECM_UNREF	7
> +#define TZCMD_MEM_SECURECM_ZALLOC	15
> +
>  /*
>   * MediaTek secure (chunk) memory type
>   *
> @@ -29,6 +32,8 @@ enum kree_mem_type {
>  struct mtk_secure_heap_buffer {
>  	struct dma_heap		*heap;
>  	size_t			size;
> +
> +	u32			sec_handle;
>  };
>  
>  struct mtk_secure_heap {
> @@ -80,6 +85,63 @@ static int mtk_kree_secure_session_init(struct mtk_secure_heap *sec_heap)
>  	return ret;
>  }
>  
> +static int
> +mtk_sec_mem_tee_service_call(struct tee_context *tee_ctx, u32 session,
> +			     unsigned int command, struct tee_param *params)
> +{
> +	struct tee_ioctl_invoke_arg arg = {0};
> +	int ret;
> +
> +	arg.num_params = MTK_TEE_PARAM_NUM;
> +	arg.session = session;
> +	arg.func = command;
> +
> +	ret = tee_client_invoke_func(tee_ctx, &arg, params);
> +	if (ret < 0 || arg.ret) {
> +		pr_err("%s: cmd %d ret %d:%x.\n", __func__, command, ret, arg.ret);
> +		ret = -EOPNOTSUPP;
> +	}
> +	return ret;
> +}
> +
> +static int mtk_sec_mem_allocate(struct mtk_secure_heap *sec_heap,
> +				struct mtk_secure_heap_buffer *sec_buf)
> +{
> +	struct tee_param params[MTK_TEE_PARAM_NUM] = {0};
> +	u32 mem_session = sec_heap->mem_session;
> +	int ret;
> +
> +	params[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT;
> +	params[0].u.value.a = SZ_4K;			/* alignment */
> +	params[0].u.value.b = sec_heap->mem_type;	/* memory type */
> +	params[1].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT;
> +	params[1].u.value.a = sec_buf->size;
> +	params[2].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INOUT;
> +
> +	/* Always request zeroed buffer */
> +	ret = mtk_sec_mem_tee_service_call(sec_heap->tee_ctx, mem_session,
> +					   TZCMD_MEM_SECURECM_ZALLOC, params);

I see here optee calls are being used to secure memory.

For a secure heap, there can be multiple ways on how we want to secure memory,
for eg : by using qcom_scm_assign_mem.

This interface restricts securing memory to only optee calls.
can we have a way to choose ops that we want to secure memory ? 

Thanks,
Vijay

> +	if (ret)
> +		return -ENOMEM;
> +
> +	sec_buf->sec_handle = params[2].u.value.a;
> +	return 0;
> +}
> +
> +static void mtk_sec_mem_release(struct mtk_secure_heap *sec_heap,
> +				struct mtk_secure_heap_buffer *sec_buf)
> +{
> +	struct tee_param params[MTK_TEE_PARAM_NUM] = {0};
> +	u32 mem_session = sec_heap->mem_session;
> +
> +	params[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT;
> +	params[0].u.value.a = sec_buf->sec_handle;
> +	params[1].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_OUTPUT;
> +
> +	mtk_sec_mem_tee_service_call(sec_heap->tee_ctx, mem_session,
> +				     TZCMD_MEM_SECURECM_UNREF, params);
> +}
> +
>  static struct dma_buf *
>  mtk_sec_heap_allocate(struct dma_heap *heap, size_t size,
>  		      unsigned long fd_flags, unsigned long heap_flags)
> @@ -107,6 +169,9 @@ mtk_sec_heap_allocate(struct dma_heap *heap, size_t size,
>  	sec_buf->size = size;
>  	sec_buf->heap = heap;
>  
> +	ret = mtk_sec_mem_allocate(sec_heap, sec_buf);
> +	if (ret)
> +		goto err_free_buf;
>  	exp_info.exp_name = dma_heap_get_name(heap);
>  	exp_info.size = sec_buf->size;
>  	exp_info.flags = fd_flags;
> @@ -115,11 +180,13 @@ mtk_sec_heap_allocate(struct dma_heap *heap, size_t size,
>  	dmabuf = dma_buf_export(&exp_info);
>  	if (IS_ERR(dmabuf)) {
>  		ret = PTR_ERR(dmabuf);
> -		goto err_free_buf;
> +		goto err_free_sec_mem;
>  	}
>  
>  	return dmabuf;
>  
> +err_free_sec_mem:
> +	mtk_sec_mem_release(sec_heap, sec_buf);
>  err_free_buf:
>  	kfree(sec_buf);
>  	return ERR_PTR(ret);