linux-kernel - Re: [PATCH] ACPI: processor: fix LPI when built as module

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Date:   Tue, 23 May 2017 14:08:06 +0100
From:   Sudeep Holla <sudeep.holla@....com>
To:     Mian Yousaf Kaukab <yousaf.kaukab@...e.com>,
        linux-acpi@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        rafael.j.wysocki@...el.com, Sudeep Holla <sudeep.holla@....com>,
        catalin.marinas@....com, lorenzo.pieralisi@....com
Subject: Re: [PATCH] ACPI: processor: fix LPI when built as module



On 19/05/17 10:28, Mian Yousaf Kaukab wrote:
> Low Power Idle(LPI) support added acpi_processor_ffh_lpi_probe() and
> acpi_processor_ffh_lpi_enter() as __weak functions and arch code is
> supposed to provide the actual callbacks. This breaks if
> ACPI_PROCESSOR is configured as a module.
> 
> Add CONFIG_ARCH_HAS_ACPI_LPI configuration option to fix this.
> 

Rafael didn't like the extra Kconfig option when I first posted
LPI patches.

> Signed-off-by: Mian Yousaf Kaukab <yousaf.kaukab@...e.com>
> ---
>  arch/arm64/Kconfig            | 1 +
>  arch/arm64/kernel/cpuidle.c   | 2 ++
>  drivers/acpi/Kconfig          | 3 +++
>  drivers/acpi/processor_idle.c | 9 +++++++--
>  4 files changed, 13 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index 848a34116c67..de2f2779cdf5 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -10,6 +10,7 @@ config ARM64
>  	select ARCH_HAS_DEBUG_VIRTUAL
>  	select ARCH_HAS_DEVMEM_IS_ALLOWED
>  	select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
> +	select ARCH_HAS_ACPI_LPI if ACPI
>  	select ARCH_HAS_ELF_RANDOMIZE
>  	select ARCH_HAS_GCOV_PROFILE_ALL
>  	select ARCH_HAS_GIGANTIC_PAGE if (MEMORY_ISOLATION && COMPACTION) || CMA
> diff --git a/arch/arm64/kernel/cpuidle.c b/arch/arm64/kernel/cpuidle.c
> index fd691087dc9a..002d9cb890bd 100644
> --- a/arch/arm64/kernel/cpuidle.c
> +++ b/arch/arm64/kernel/cpuidle.c
> @@ -51,9 +51,11 @@ int acpi_processor_ffh_lpi_probe(unsigned int cpu)
>  {
>  	return arm_cpuidle_init(cpu);
>  }
> +EXPORT_SYMBOL(acpi_processor_ffh_lpi_probe);
>  
>  int acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi)
>  {
>  	return CPU_PM_CPU_IDLE_ENTER(arm_cpuidle_suspend, lpi->index);
>  }
> +EXPORT_SYMBOL(acpi_processor_ffh_lpi_enter);

Won't these 2 export suffice ? I am just curious why that won't work.
Will weak function definitions be still picked when built as modules ?

-- 
Regards,
Sudeep