Re: [PATCH v9 3/7] firmware: arm_rmm: Move RSI support out of arch/arm64

[Aneesh Kumar K.V <aneesh.kumar@kernel.org>]

Catalin Marinas <catalin.marinas@arm.com> writes:

> On Wed, Aug 05, 2026 at 12:02:51PM +0530, Aneesh Kumar K.V (Arm) wrote:
>> The RSI SMCCC function IDs describe a firmware ABI and are not arm64
>> architecture specific definitions. Follow-up changes need to use them from
>> non-arch code, including drivers/firmware/smccc and the Arm CCA guest
>> driver.
>> 
>> Move the complete Realm Service Interface (RSI) implementation from
>> arch/arm64 to drivers/firmware/arm_rmm. The RSI SMCCC definitions and
>> command helpers are also moved to include/linux so they can be shared by
>> architecture code and firmware or driver code. This also keeps the
>> firmware interface outside architecture code, as requested [1].
>> 
>> [1] https://lore.kernel.org/all/agsNO9cc7H-b0H8L@willie-the-truck
>> 
>> Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
>
> I haven't checked but Sashiko has some points that it may break the
> build on other architectures with COMPILE_TEST.
>
> https://sashiko.dev/#/patchset/20260805063255.1638614-1-aneesh.kumar@kernel.org
>
> (for some reason I get error 502 above; hopefully it's temporary)
>

Below is the sashiko output

>> -#endif /* __ASM_RSI_CMDS_H */
>> +#endif /* __LINUX_ARM_RSI_CMDS_H_ */
> Now that this header is moved to include/linux/ to be shared by cross
> architecture code, will it break non-ARM64 builds?
> Looking at rsi_attestation_token_init() further up in this file:
>    struct arm_smccc_1_2_regs regs;
>    ...
>    arm_smccc_1_2_smc(&args.regs, &args.regs);
>    
> Both struct arm_smccc_1_2_regs and arm_smccc_1_2_smc() are guarded by
> CONFIG_ARM64 in include/linux/arm-smccc.h. If a generic firmware driver
> using COMPILE_TEST includes this header on a different architecture, it
> seems compilation will fail.

Only arm64 code is including that header for now.

arch/arm64/mm/init.c:37:#include <linux/arm-rsi-cmds.h>
arch/arm64/include/asm/mem_encrypt.h:5:#include <linux/arm-rsi-cmds.h>
arch/arm64/include/asm/pgtable-prot.h:69:#include <linux/arm-rsi-cmds.h>
arch/arm64/include/asm/io.h:11:#include <linux/arm-rsi-cmds.h>
arch/arm64/kernel/setup.c:10:#include <linux/arm-rsi-cmds.h>
drivers/virt/coco/arm-cca-guest/arm-cca.c:6:#include <linux/arm-rsi-cmds.h>
drivers/firmware/arm_rmm/rsi.c:11:#include <linux/arm-rsi-cmds.h>

-aneesh