Re: [PATCH v2 12/12] tee: refactor TEE_SHM_* flags

[Sumit Garg]

On Fri, 14 Jan 2022 at 20:38, Jens Wiklander <jens.wiklander@xxxxxxxxxx> wrote:
>
> Removes the redundant TEE_SHM_DMA_BUF, TEE_SHM_EXT_DMA_BUF,
> TEE_SHM_MAPPED and TEE_SHM_KERNEL_MAPPED flags.
>
> Assigns new values to the remaining flags to void gaps.
>
> Signed-off-by: Jens Wiklander <jens.wiklander@xxxxxxxxxx>
> ---
>  drivers/tee/tee_shm.c   | 21 ++++++++++-----------
>  include/linux/tee_drv.h | 12 ++++--------
>  2 files changed, 14 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c
> index fe3e5977dd7c..9945bdec086b 100644
> --- a/drivers/tee/tee_shm.c
> +++ b/drivers/tee/tee_shm.c
> @@ -139,8 +139,7 @@ static struct tee_shm *shm_alloc_helper(struct tee_context *ctx, size_t size,
>   */
>  struct tee_shm *tee_shm_alloc_user_buf(struct tee_context *ctx, size_t size)
>  {
> -       u32 flags = TEE_SHM_MAPPED | TEE_SHM_DMA_BUF | TEE_SHM_REGISTER |
> -                   TEE_SHM_POOL;
> +       u32 flags = TEE_SHM_REGISTER | TEE_SHM_POOL;
>         struct tee_device *teedev = ctx->teedev;
>         struct tee_shm *shm;
>         void *ret;
> @@ -186,7 +185,7 @@ EXPORT_SYMBOL_GPL(tee_shm_alloc_user_buf);
>   */
>  struct tee_shm *tee_shm_alloc_kernel_buf(struct tee_context *ctx, size_t size)
>  {
> -       u32 flags = TEE_SHM_MAPPED | TEE_SHM_REGISTER | TEE_SHM_POOL;
> +       u32 flags = TEE_SHM_REGISTER | TEE_SHM_POOL;
>
>         return shm_alloc_helper(ctx, size, PAGE_SIZE, flags, -1);
>  }
> @@ -211,7 +210,7 @@ EXPORT_SYMBOL_GPL(tee_shm_alloc_kernel_buf);
>  struct tee_shm *tee_shm_alloc_priv_kernel_buf(struct tee_context *ctx,
>                                               size_t size)
>  {
> -       u32 flags = TEE_SHM_MAPPED | TEE_SHM_PRIV | TEE_SHM_POOL;
> +       u32 flags = TEE_SHM_PRIV | TEE_SHM_POOL;
>
>         return shm_alloc_helper(ctx, size, sizeof(long) * 2, flags, -1);
>  }
> @@ -308,7 +307,7 @@ register_shm_helper(struct tee_context *ctx, unsigned long addr,
>  struct tee_shm *tee_shm_register_user_buf(struct tee_context *ctx,
>                                           unsigned long addr, size_t length)
>  {
> -       u32 f = TEE_SHM_DMA_BUF | TEE_SHM_USER_MAPPED | TEE_SHM_REGISTER;
> +       u32 f = TEE_SHM_USER_MAPPED | TEE_SHM_REGISTER;
>         struct tee_device *teedev = ctx->teedev;
>         struct tee_shm *shm;
>         void *ret;
> @@ -354,7 +353,7 @@ EXPORT_SYMBOL_GPL(tee_shm_register_user_buf);
>  struct tee_shm *tee_shm_register_kernel_buf(struct tee_context *ctx,
>                                             void *addr, size_t length)
>  {
> -       u32 f = TEE_SHM_REGISTER | TEE_SHM_KERNEL_MAPPED;
> +       u32 f = TEE_SHM_REGISTER;
>
>         return register_shm_helper(ctx, (unsigned long)addr, length, f, -1);
>  }
> @@ -398,7 +397,7 @@ int tee_shm_get_fd(struct tee_shm *shm)
>  {
>         int fd;
>
> -       if (!(shm->flags & TEE_SHM_DMA_BUF))
> +       if (shm->id < 0)
>                 return -EINVAL;
>
>         /* matched by tee_shm_put() in tee_shm_op_release() */
> @@ -428,7 +427,7 @@ EXPORT_SYMBOL_GPL(tee_shm_free);
>   */
>  int tee_shm_va2pa(struct tee_shm *shm, void *va, phys_addr_t *pa)
>  {
> -       if (!(shm->flags & TEE_SHM_MAPPED))
> +       if (!shm->kaddr)
>                 return -EINVAL;
>         /* Check that we're in the range of the shm */
>         if ((char *)va < (char *)shm->kaddr)
> @@ -450,7 +449,7 @@ EXPORT_SYMBOL_GPL(tee_shm_va2pa);
>   */
>  int tee_shm_pa2va(struct tee_shm *shm, phys_addr_t pa, void **va)
>  {
> -       if (!(shm->flags & TEE_SHM_MAPPED))
> +       if (!shm->kaddr)
>                 return -EINVAL;
>         /* Check that we're in the range of the shm */
>         if (pa < shm->paddr)
> @@ -478,7 +477,7 @@ EXPORT_SYMBOL_GPL(tee_shm_pa2va);
>   */
>  void *tee_shm_get_va(struct tee_shm *shm, size_t offs)
>  {
> -       if (!(shm->flags & TEE_SHM_MAPPED))
> +       if (!shm->kaddr)
>                 return ERR_PTR(-EINVAL);
>         if (offs >= shm->size)
>                 return ERR_PTR(-EINVAL);
> @@ -553,7 +552,7 @@ void tee_shm_put(struct tee_shm *shm)
>                  * the refcount_inc() in tee_shm_get_from_id() never starts
>                  * from 0.
>                  */
> -               if (shm->flags & TEE_SHM_DMA_BUF)
> +               if (shm->id >= 0)
>                         idr_remove(&teedev->idr, shm->id);
>                 do_release = true;
>         }
> diff --git a/include/linux/tee_drv.h b/include/linux/tee_drv.h
> index e4f32885e273..dcc7a55e1128 100644
> --- a/include/linux/tee_drv.h
> +++ b/include/linux/tee_drv.h
> @@ -20,14 +20,10 @@
>   * specific TEE driver.
>   */
>
> -#define TEE_SHM_MAPPED         BIT(0)  /* Memory mapped by the kernel */
> -#define TEE_SHM_DMA_BUF                BIT(1)  /* Memory with dma-buf handle */
> -#define TEE_SHM_EXT_DMA_BUF    BIT(2)  /* Memory with dma-buf handle */
> -#define TEE_SHM_REGISTER       BIT(3)  /* Memory registered in secure world */
> -#define TEE_SHM_USER_MAPPED    BIT(4)  /* Memory mapped in user space */
> -#define TEE_SHM_POOL           BIT(5)  /* Memory allocated from pool */
> -#define TEE_SHM_KERNEL_MAPPED  BIT(6)  /* Memory mapped in kernel space */
> -#define TEE_SHM_PRIV           BIT(7)  /* Memory private to TEE driver */
> +#define TEE_SHM_REGISTER       BIT(0)  /* Memory registered in secure world */

TEE_SHM_REGISTER as a flag name seems ambiguous to me when it is being
used by both types of APIs tee_shm_alloc_* and tee_shm_register_*. Can
we rename it to TEE_SHM_DYNAMIC instead?

-Sumit

> +#define TEE_SHM_USER_MAPPED    BIT(1)  /* Memory mapped in user space */
> +#define TEE_SHM_POOL           BIT(2)  /* Memory allocated from pool */
> +#define TEE_SHM_PRIV           BIT(3)  /* Memory private to TEE driver */
>
>  struct device;
>  struct tee_device;
> --
> 2.31.1
>