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SubjectRe: [PATCH 3/4] tee: amdtee: check TEE status during driver initialization
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On 12/26/19 11:24 PM, Rijo Thomas wrote:
> The AMD-TEE driver should check if TEE is available before
> registering itself with TEE subsystem. This ensures that
> there is a TEE which the driver can talk to before proceeding
> with tee device node allocation.
>
> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> Cc: Tom Lendacky <thomas.lendacky@amd.com>
> Acked-by: Jens Wiklander <jens.wiklander@linaro.org>
> Co-developed-by: Devaraj Rangasamy <Devaraj.Rangasamy@amd.com>
> Signed-off-by: Devaraj Rangasamy <Devaraj.Rangasamy@amd.com>
> Signed-off-by: Rijo Thomas <Rijo-john.Thomas@amd.com>

Reviewed-by: Gary R Hook <gary.hook@amd.com>

> ---
> drivers/crypto/ccp/tee-dev.c | 11 +++++++++++
> drivers/tee/amdtee/core.c | 6 ++++++
> include/linux/psp-tee.h | 18 ++++++++++++++++++
> 3 files changed, 35 insertions(+)
>
> diff --git a/drivers/crypto/ccp/tee-dev.c b/drivers/crypto/ccp/tee-dev.c
> index 555c8a7..5e697a9 100644
> --- a/drivers/crypto/ccp/tee-dev.c
> +++ b/drivers/crypto/ccp/tee-dev.c
> @@ -362,3 +362,14 @@ int psp_tee_process_cmd(enum tee_cmd_id cmd_id, void *buf, size_t len,
> return 0;
> }
> EXPORT_SYMBOL(psp_tee_process_cmd);
> +
> +int psp_check_tee_status(void)
> +{
> + struct psp_device *psp = psp_get_master_device();
> +
> + if (!psp || !psp->tee_data)
> + return -ENODEV;
> +
> + return 0;
> +}
> +EXPORT_SYMBOL(psp_check_tee_status);
> diff --git a/drivers/tee/amdtee/core.c b/drivers/tee/amdtee/core.c
> index dd360f3..9d0cee1 100644
> --- a/drivers/tee/amdtee/core.c
> +++ b/drivers/tee/amdtee/core.c
> @@ -16,6 +16,7 @@
> #include <linux/firmware.h>
> #include "amdtee_private.h"
> #include "../tee_private.h"
> +#include <linux/psp-tee.h>
>
> static struct amdtee_driver_data *drv_data;
> static DEFINE_MUTEX(session_list_mutex);
> @@ -438,6 +439,10 @@ static int __init amdtee_driver_init(void)
> struct tee_shm_pool *pool = ERR_PTR(-EINVAL);
> int rc;
>
> + rc = psp_check_tee_status();
> + if (rc)
> + goto err_fail;
> +
> drv_data = kzalloc(sizeof(*drv_data), GFP_KERNEL);
> if (IS_ERR(drv_data))
> return -ENOMEM;
> @@ -485,6 +490,7 @@ static int __init amdtee_driver_init(void)
> kfree(drv_data);
> drv_data = NULL;
>
> +err_fail:
> pr_err("amd-tee driver initialization failed\n");
> return rc;
> }
> diff --git a/include/linux/psp-tee.h b/include/linux/psp-tee.h
> index 63bb221..cb0c95d 100644
> --- a/include/linux/psp-tee.h
> +++ b/include/linux/psp-tee.h
> @@ -62,6 +62,19 @@ enum tee_cmd_id {
> int psp_tee_process_cmd(enum tee_cmd_id cmd_id, void *buf, size_t len,
> u32 *status);
>
> +/**
> + * psp_check_tee_status() - Checks whether there is a TEE which a driver can
> + * talk to.
> + *
> + * This function can be used by AMD-TEE driver to query if there is TEE with
> + * which it can communicate.
> + *
> + * Returns:
> + * 0 if the device has TEE
> + * -%ENODEV if there is no TEE available
> + */
> +int psp_check_tee_status(void);
> +
> #else /* !CONFIG_CRYPTO_DEV_SP_PSP */
>
> static inline int psp_tee_process_cmd(enum tee_cmd_id cmd_id, void *buf,
> @@ -69,5 +82,10 @@ static inline int psp_tee_process_cmd(enum tee_cmd_id cmd_id, void *buf,
> {
> return -ENODEV;
> }
> +
> +static inline int psp_check_tee_status(void)
> +{
> + return -ENODEV;
> +}
> #endif /* CONFIG_CRYPTO_DEV_SP_PSP */
> #endif /* __PSP_TEE_H_ */
>

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