linux-kernel - Re: [PATCH v2] clocksource/arm_arch_timer: extract elf

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Date:   Thu, 13 Jun 2019 15:08:51 +0200
From:   Daniel Lezcano <daniel.lezcano@...aro.org>
To:     Marc Zyngier <marc.zyngier@....com>,
        Andrew Murray <andrew.murray@....com>
Cc:     Mark Rutland <mark.rutland@....com>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will.deacon@....com>,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v2] clocksource/arm_arch_timer: extract elf_hwcap use to
 arch-helper

On 13/06/2019 15:03, Marc Zyngier wrote:
> + Daniel
> 
> On Thu, 13 Jun 2019 13:51:02 +0100,
> Andrew Murray <andrew.murray@....com> wrote:
>>
>> Different mechanisms are used to test and set elf_hwcaps between ARM
>> and ARM64, this results in the use of ifdeferry in this file when
>> setting/testing for the EVTSTRM hwcap.
>>
>> Let's improve readability by extracting this to an arch helper.
>>
>> Signed-off-by: Andrew Murray <andrew.murray@....com>
>> Acked-by: Mark Rutland <mark.rutland@....com>
>> Acked-by: Will Deacon <will.deacon@....com>
> 
> Acked-by: Marc Zyngier <marc.zyngier@....com>
> 
> Daniel, can you please take this though the clocksource tree?

Applied, thanks

  -- Daniel

>> ---
>>  arch/arm/include/asm/arch_timer.h    | 10 ++++++++++
>>  arch/arm64/include/asm/arch_timer.h  | 13 +++++++++++++
>>  drivers/clocksource/arm_arch_timer.c | 15 ++-------------
>>  3 files changed, 25 insertions(+), 13 deletions(-)
>>
>> diff --git a/arch/arm/include/asm/arch_timer.h b/arch/arm/include/asm/arch_timer.h
>> index 4b66ecd6be99..ae533caec1e9 100644
>> --- a/arch/arm/include/asm/arch_timer.h
>> +++ b/arch/arm/include/asm/arch_timer.h
>> @@ -4,6 +4,7 @@
>>  
>>  #include <asm/barrier.h>
>>  #include <asm/errno.h>
>> +#include <asm/hwcap.h>
>>  #include <linux/clocksource.h>
>>  #include <linux/init.h>
>>  #include <linux/types.h>
>> @@ -124,6 +125,15 @@ static inline void arch_timer_set_cntkctl(u32 cntkctl)
>>  	isb();
>>  }
>>  
>> +static inline bool arch_timer_set_evtstrm_feature(void)
>> +{
>> +	elf_hwcap |= HWCAP_EVTSTRM;
>> +}
>> +
>> +static inline bool arch_timer_have_evtstrm_feature(void)
>> +{
>> +	return elf_hwcap & HWCAP_EVTSTRM;
>> +}
>>  #endif
>>  
>>  #endif
>> diff --git a/arch/arm64/include/asm/arch_timer.h b/arch/arm64/include/asm/arch_timer.h
>> index 50b3ab7ded4f..a847a3ee6cab 100644
>> --- a/arch/arm64/include/asm/arch_timer.h
>> +++ b/arch/arm64/include/asm/arch_timer.h
>> @@ -20,6 +20,7 @@
>>  #define __ASM_ARCH_TIMER_H
>>  
>>  #include <asm/barrier.h>
>> +#include <asm/hwcap.h>
>>  #include <asm/sysreg.h>
>>  
>>  #include <linux/bug.h>
>> @@ -240,4 +241,16 @@ static inline int arch_timer_arch_init(void)
>>  	return 0;
>>  }
>>  
>> +static inline void arch_timer_set_evtstrm_feature(void)
>> +{
>> +	cpu_set_named_feature(EVTSTRM);
>> +#ifdef CONFIG_COMPAT
>> +	compat_elf_hwcap |= COMPAT_HWCAP_EVTSTRM;
>> +#endif
>> +}
>> +
>> +static inline bool arch_timer_have_evtstrm_feature(void)
>> +{
>> +	return cpu_have_named_feature(EVTSTRM);
>> +}
>>  #endif
>> diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
>> index b2a951a798e2..3583a92ad960 100644
>> --- a/drivers/clocksource/arm_arch_timer.c
>> +++ b/drivers/clocksource/arm_arch_timer.c
>> @@ -804,14 +804,7 @@ static void arch_timer_evtstrm_enable(int divider)
>>  	cntkctl |= (divider << ARCH_TIMER_EVT_TRIGGER_SHIFT)
>>  			| ARCH_TIMER_VIRT_EVT_EN;
>>  	arch_timer_set_cntkctl(cntkctl);
>> -#ifdef CONFIG_ARM64
>> -	cpu_set_named_feature(EVTSTRM);
>> -#else
>> -	elf_hwcap |= HWCAP_EVTSTRM;
>> -#endif
>> -#ifdef CONFIG_COMPAT
>> -	compat_elf_hwcap |= COMPAT_HWCAP_EVTSTRM;
>> -#endif
>> +	arch_timer_set_evtstrm_feature();
>>  	cpumask_set_cpu(smp_processor_id(), &evtstrm_available);
>>  }
>>  
>> @@ -1040,11 +1033,7 @@ static int arch_timer_cpu_pm_notify(struct notifier_block *self,
>>  	} else if (action == CPU_PM_ENTER_FAILED || action == CPU_PM_EXIT) {
>>  		arch_timer_set_cntkctl(__this_cpu_read(saved_cntkctl));
>>  
>> -#ifdef CONFIG_ARM64
>> -		if (cpu_have_named_feature(EVTSTRM))
>> -#else
>> -		if (elf_hwcap & HWCAP_EVTSTRM)
>> -#endif
>> +		if (arch_timer_have_evtstrm_feature())
>>  			cpumask_set_cpu(smp_processor_id(), &evtstrm_available);
>>  	}
>>  	return NOTIFY_OK;
>> -- 
>> 2.21.0
>>
> 


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