[PATCH v3 10/13] drivers/firmware/scmi: disable ftrace for Clang Thumb2 builds

[Sudeep Holla]

On Thu, Feb 03, 2022 at 09:22:01AM +0100, Ard Biesheuvel wrote:
> The SMC calling convention designates R0-R7 as input registers in
> AArch32 mode, and this conflicts with the compiler's use of R7 as a
> frame pointer when building in Thumb2 mode. Generally, we don't enable
> the frame pointer, and GCC happily enables the -pg profiling hooks
> without them. However, Clang refuses, and errors out with the message
> below:
> 
> drivers/firmware/arm_scmi/smc.c:152:2: error: write to reserved register 'R7'
>         arm_smccc_1_1_invoke(scmi_info->func_id, 0, 0, 0, 0, 0, 0, 0, &res);
>         ^
> include/linux/arm-smccc.h:550:4: note: expanded from macro 'arm_smccc_1_1_invoke'
>                         arm_smccc_1_1_smc(__VA_ARGS__);                 \
>                         ^
> Let's just disable ftrace for the compilation unit when building this
> configuration.
> 
> Signed-off-by: Ard Biesheuvel <ardb at kernel.org>
> Reviewed-by: Nick Desaulniers <ndesaulniers at google.com>
> Acked-by: Sudeep Holla <sudeep.holla at arm.com>

I know I already acked, but wanted to check if you want to take this as series
or you want me to apply this one myself. I don't see any dependency on other
patches but thought I will check with you and your plans.

I am happy to take this patch alone if you prefer that. Let me know.

-- 
Regards,
Sudeep