[PATCH v4] tee: optee: build the Arm-specific code only on Arm

[PATCH v4] tee: optee: build the Arm-specific code only on Arm

[marouene.boubakri]

From: Marouene Boubakri <marouene.boubakri@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@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
 	};
 	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
-- 
2.43.0

Re: [PATCH v4] tee: optee: build the Arm-specific code only on Arm

[Jens Wiklander]

Hi,

On Thu, Sep 24, 2026 at 12:37 PM <marouene.boubakri@oss.nxp.com> wrote:
>
> From: Marouene Boubakri <marouene.boubakri@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@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(-)

Looks good, I'm picking this up.

Cheers,
Jens

Re: [PATCH v4] tee: optee: build the Arm-specific code only on Arm

[Amirreza Zarrabi]

Hi Marouene,

On 9/24/2026 8:51 PM, marouene.boubakri@oss.nxp.com wrote:
> From: Marouene Boubakri <marouene.boubakri@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@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

>  	};
>  	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

Re: [PATCH v4] tee: optee: build the Arm-specific code only on Arm

[Amirreza Zarrabi]

On 10/2/2026 6:27 AM, Amirreza Zarrabi wrote:
> Hi Marouene,
> 
> On 9/24/2026 8:51 PM, marouene.boubakri@oss.nxp.com wrote:
>> From: Marouene Boubakri <marouene.boubakri@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@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
>