[PATCH v4] tee: optee: build the Arm-specific code only on Arm
Amirreza Zarrabi
amirreza.zarrabi at oss.qualcomm.com
Thu Oct 1 16:31:02 PDT 2026
On 10/2/2026 6:27 AM, Amirreza Zarrabi wrote:
> Hi Marouene,
>
> On 9/24/2026 8:51 PM, marouene.boubakri at oss.nxp.com wrote:
>> From: Marouene Boubakri <marouene.boubakri at oss.nxp.com>
>>
>> The OP-TEE driver reaches OP-TEE through the SMC ABI or the FF-A ABI,
>> both specific to Arm, yet builds both unconditionally together with the
>> SMC Calling Convention definitions they rely on: ffa_abi.c is always
>> compiled and only its registration is conditioned on
>> IS_REACHABLE(CONFIG_ARM_FFA_TRANSPORT), and optee_private.h includes
>> <linux/arm-smccc.h> and defines the SMC and FF-A specific types for
>> every file of the driver. This is fine as long as the driver depends on
>> HAVE_ARM_SMCCC, but it keeps the driver from being built for an
>> architecture without SMCCC, such as RISC-V.
>>
>> Build smc_abi.c only when HAVE_ARM_SMCCC is set and ffa_abi.c only when
>> the FF-A transport is enabled, and provide stubs for their registration
>> otherwise, so that it fails with -EOPNOTSUPP as the FF-A ABI already
>> does when the FF-A transport is not reachable. Keep the SMCCC header,
>> the SMC invoke function type, the SMC and FF-A specific structures and
>> the SMC RPC register parameters in optee_private.h under the same
>> conditions, and drop the unused <linux/arm-smccc.h> include from
>> notif.c.
>>
>> Make OPTEE depend on ARM_FFA_TRANSPORT || !ARM_FFA_TRANSPORT, as it
>> already does for RPMB, so that the driver is limited to a module when
>> the FF-A transport is one, rather than built in without FF-A support.
>> ffa_abi.c is thus built exactly when the FF-A transport is reachable
>> from the driver, and the IS_REACHABLE() checks in
>> optee_ffa_abi_register() and optee_ffa_abi_unregister() are always
>> true, so drop them.
>>
>> OPTEE still depends on HAVE_ARM_SMCCC, so smc_abi.c is still always
>> built. The only visible change is that OPTEE=y can no longer be
>> combined with ARM_FFA_TRANSPORT=m: such a configuration now resolves to
>> OPTEE=m, with the FF-A ABI available.
>>
>> Signed-off-by: Marouene Boubakri <marouene.boubakri at oss.nxp.com>
>> ---
>> Changes in v4:
>> - Make OPTEE depend on ARM_FFA_TRANSPORT || !ARM_FFA_TRANSPORT so that
>> the driver is limited to =m when the FF-A transport is =m (Jens).
>> - Update the commit message accordingly.
>> v3: https://lore.kernel.org/all/20260922131735.524635-1-marouene.boubakri@oss.nxp.com/
>>
>> Changes in v3:
>> - Dropped the RPMI ABI placeholder and the RISC-V enablement patches,
>> this is now a single patch (Jens).
>> - Key the FF-A parts of optee_private.h on IS_REACHABLE() instead of
>> IS_ENABLED(): with OPTEE=y and ARM_FFA_TRANSPORT=m kbuild drops
>> ffa_abi.o from the built-in optee.o while optee_ffa_abi_register()
>> was still declared, which does not link.
>> - Drop the now always true IS_REACHABLE() checks in
>> optee_ffa_abi_register() and optee_ffa_abi_unregister().
>> - Describe the current FF-A conditional compilation accurately in the
>> commit message.
>> - Posted as a new thread with a proper subject prefix.
>> v2: https://lore.kernel.org/op-tee/20260915020235.507302-2-marouene.boubakri@oss.nxp.com/
>>
>> Changes in v2:
>> - No code change, the testing section of the cover letter was completed.
>> v1: https://lore.kernel.org/op-tee/20260914175435.118303-2-marouene.boubakri@oss.nxp.com/
>> drivers/tee/optee/Kconfig | 1 +
>> drivers/tee/optee/Makefile | 4 ++--
>> drivers/tee/optee/ffa_abi.c | 8 ++-----
>> drivers/tee/optee/notif.c | 1 -
>> drivers/tee/optee/optee_private.h | 39 ++++++++++++++++++++++++++++++-
>> 5 files changed, 43 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/tee/optee/Kconfig b/drivers/tee/optee/Kconfig
>> index 50d2051..891dac6 100644
>> --- a/drivers/tee/optee/Kconfig
>> +++ b/drivers/tee/optee/Kconfig
>> @@ -5,6 +5,7 @@ config OPTEE
>> depends on HAVE_ARM_SMCCC
>> depends on MMU
>> depends on RPMB || !RPMB
>> + depends on ARM_FFA_TRANSPORT || !ARM_FFA_TRANSPORT
>> help
>> This implements the OP-TEE Trusted Execution Environment (TEE)
>> driver.
>> diff --git a/drivers/tee/optee/Makefile b/drivers/tee/optee/Makefile
>> index ad7049c..183cdde 100644
>> --- a/drivers/tee/optee/Makefile
>> +++ b/drivers/tee/optee/Makefile
>> @@ -7,8 +7,8 @@ optee-objs += rpc.o
>> optee-objs += protmem.o
>> optee-objs += supp.o
>> optee-objs += device.o
>> -optee-objs += smc_abi.o
>> -optee-objs += ffa_abi.o
>> +optee-$(CONFIG_HAVE_ARM_SMCCC) += smc_abi.o
>> +optee-$(CONFIG_ARM_FFA_TRANSPORT) += ffa_abi.o
>>
>> # for tracing framework to find optee_trace.h
>> CFLAGS_smc_abi.o := -I$(src)
>> diff --git a/drivers/tee/optee/ffa_abi.c b/drivers/tee/optee/ffa_abi.c
>> index 633715b..08236d8 100644
>> --- a/drivers/tee/optee/ffa_abi.c
>> +++ b/drivers/tee/optee/ffa_abi.c
>> @@ -1212,14 +1212,10 @@ static struct ffa_driver optee_ffa_driver = {
>>
>> int optee_ffa_abi_register(void)
>> {
>> - if (IS_REACHABLE(CONFIG_ARM_FFA_TRANSPORT))
>> - return ffa_register(&optee_ffa_driver);
>> - else
>> - return -EOPNOTSUPP;
>> + return ffa_register(&optee_ffa_driver);
>> }
>>
>> void optee_ffa_abi_unregister(void)
>> {
>> - if (IS_REACHABLE(CONFIG_ARM_FFA_TRANSPORT))
>> - ffa_unregister(&optee_ffa_driver);
>> + ffa_unregister(&optee_ffa_driver);
>> }
>> diff --git a/drivers/tee/optee/notif.c b/drivers/tee/optee/notif.c
>> index 6e85f2f..6801422 100644
>> --- a/drivers/tee/optee/notif.c
>> +++ b/drivers/tee/optee/notif.c
>> @@ -5,7 +5,6 @@
>>
>> #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>>
>> -#include <linux/arm-smccc.h>
>> #include <linux/errno.h>
>> #include <linux/slab.h>
>> #include <linux/spinlock.h>
>> diff --git a/drivers/tee/optee/optee_private.h b/drivers/tee/optee/optee_private.h
>> index aefe1e6..02d6f79 100644
>> --- a/drivers/tee/optee/optee_private.h
>> +++ b/drivers/tee/optee/optee_private.h
>> @@ -6,7 +6,6 @@
>> #ifndef OPTEE_PRIVATE_H
>> #define OPTEE_PRIVATE_H
>>
>> -#include <linux/arm-smccc.h>
>> #include <linux/notifier.h>
>> #include <linux/rhashtable.h>
>> #include <linux/rpmb.h>
>> @@ -15,6 +14,10 @@
>> #include <linux/types.h>
>> #include "optee_msg.h"
>>
>> +#ifdef CONFIG_HAVE_ARM_SMCCC
>> +#include <linux/arm-smccc.h>
>> +#endif
>> +
>> #define DRIVER_NAME "optee"
>>
>> #define OPTEE_MAX_ARG_SIZE 1024
>> @@ -42,10 +45,12 @@
>> */
>> #define OPTEE_DEFAULT_MAX_NOTIF_VALUE 255
>>
>> +#ifdef CONFIG_HAVE_ARM_SMCCC
>> typedef void (optee_invoke_fn)(unsigned long, unsigned long, unsigned long,
>> unsigned long, unsigned long, unsigned long,
>> unsigned long, unsigned long,
>> struct arm_smccc_res *);
>> +#endif
>>
>> /**
>> * struct optee_call_waiter - TEE entry may need to wait for a free TEE thread
>> @@ -119,6 +124,7 @@ struct optee_supp {
>> struct completion reqs_c;
>> };
>>
>> +#ifdef CONFIG_HAVE_ARM_SMCCC
>> /**
>> * struct optee_pcpu - per cpu notif private struct passed to work functions
>> * @optee: optee device reference
>> @@ -149,7 +155,9 @@ struct optee_smc {
>> struct work_struct notif_pcpu_work;
>> unsigned int notif_cpuhp_state;
>> };
>> +#endif
>>
>> +#if IS_REACHABLE(CONFIG_ARM_FFA_TRANSPORT)
>> /**
>> * struct optee_ffa - FFA communication struct
>> * @ffa_dev: FFA device, contains the destination id, the id of
>> @@ -170,6 +178,7 @@ struct optee_ffa {
>> struct workqueue_struct *notif_wq;
>> struct work_struct notif_work;
>> };
>> +#endif
>>
>> struct optee;
>>
>> @@ -257,8 +266,12 @@ struct optee {
>> const struct optee_ops *ops;
>> struct tee_context *ctx;
>> union {
>> +#ifdef CONFIG_HAVE_ARM_SMCCC
>> struct optee_smc smc;
>> +#endif
>> +#if IS_REACHABLE(CONFIG_ARM_FFA_TRANSPORT)
>> struct optee_ffa ffa;
>> +#endif
>
> Does this need to be a union if we filter the members?
>
> Best Regards,
> Amir
>
Ok, got my answer. We need both support in the binary, like before.
Thanks,
- Amir
>> };
>> struct optee_shm_arg_cache shm_arg_cache;
>> struct optee_call_queue call_queue;
>> @@ -290,6 +303,7 @@ struct optee_context_data {
>> struct list_head sess_list;
>> };
>>
>> +#ifdef CONFIG_HAVE_ARM_SMCCC
>> struct optee_rpc_param {
>> u32 a0;
>> u32 a1;
>> @@ -300,6 +314,7 @@ struct optee_rpc_param {
>> u32 a6;
>> u32 a7;
>> };
>> +#endif
>>
>> /* Holds context that is preserved during one STD call */
>> struct optee_call_ctx {
>> @@ -422,9 +437,31 @@ static inline void reg_pair_from_64(u32 *reg0, u32 *reg1, u64 val)
>> }
>>
>> /* Registration of the ABIs */
>> +#ifdef CONFIG_HAVE_ARM_SMCCC
>> int optee_smc_abi_register(void);
>> void optee_smc_abi_unregister(void);
>> +#else
>> +static inline int optee_smc_abi_register(void)
>> +{
>> + return -EOPNOTSUPP;
>> +}
>> +
>> +static inline void optee_smc_abi_unregister(void)
>> +{
>> +}
>> +#endif
>> +#if IS_REACHABLE(CONFIG_ARM_FFA_TRANSPORT)
>> int optee_ffa_abi_register(void);
>> void optee_ffa_abi_unregister(void);
>> +#else
>> +static inline int optee_ffa_abi_register(void)
>> +{
>> + return -EOPNOTSUPP;
>> +}
>> +
>> +static inline void optee_ffa_abi_unregister(void)
>> +{
>> +}
>> +#endif
>>
>> #endif /*OPTEE_PRIVATE_H*/
>>
>> base-commit: 827751b699b79a6e569983359c02dce67f81b94c
>
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