Re: [PATCH] arm64: armv8_deprecated: fix unused-function error

From: Mark Rutland
Date: Tue Nov 22 2022 - 11:49:03 EST


On Tue, Nov 22, 2022 at 03:20:10AM +0000, Ren Zhijie wrote:
> If CONFIG_SWP_EMULATION is not set and
> CONFIG_CP15_BARRIER_EMULATION is not set,
> aarch64-linux-gnu complained about unused-function :
>
> arch/arm64/kernel/armv8_deprecated.c:67:21: error: ‘aarch32_check_condition’ defined but not used [-Werror=unused-function]
> static unsigned int aarch32_check_condition(u32 opcode, u32 psr)
> ^~~~~~~~~~~~~~~~~~~~~~~
> cc1: all warnings being treated as errors
>
> To fix this error, warp the definition of
> aarch32_check_condition() by defined(CONFIG_SWP_EMULATION) ||
> defined(CONFIG_CP15_BARRIER_EMULATION)
>
> Fixes: 0c5f416219da ("arm64: armv8_deprecated: move aarch32 helper earlier")

This also depends on building with additional options to turn warnings into
errors, no?

> Signed-off-by: Ren Zhijie <renzhijie2@xxxxxxxxxx>
> ---
> arch/arm64/kernel/armv8_deprecated.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/arch/arm64/kernel/armv8_deprecated.c b/arch/arm64/kernel/armv8_deprecated.c
> index ed0788cf6bbb..3f29ceb6653a 100644
> --- a/arch/arm64/kernel/armv8_deprecated.c
> +++ b/arch/arm64/kernel/armv8_deprecated.c
> @@ -64,6 +64,7 @@ struct insn_emulation {
>
> #define ARM_OPCODE_CONDITION_UNCOND 0xf
>
> +#if defined(CONFIG_SWP_EMULATION) || defined(CONFIG_CP15_BARRIER_EMULATION)
> static unsigned int aarch32_check_condition(u32 opcode, u32 psr)
> {
> u32 cc_bits = opcode >> 28;
> @@ -76,6 +77,7 @@ static unsigned int aarch32_check_condition(u32 opcode, u32 psr)
> }
> return ARM_OPCODE_CONDTEST_UNCOND;
> }
> +#endif

Could we mark this as '__maybe_unused' or 'inline' instead? I think that's
preferable to the ifdeferry.

Thanks,
Mark.

>
> #ifdef CONFIG_SWP_EMULATION
> /*
> --
> 2.17.1
>