Re: [PATCH v2] ACPI: processor: Fix build when CONFIG_ACPI_PROCESSOR=m
On Tue, Apr 6, 2021 at 5:39 PM Vitaly Kuznetsov wrote:
>
> "Rafael J. Wysocki" writes:
>
> > On Tue, Apr 6, 2021 at 4:01 PM Vitaly Kuznetsov wrote:
> >>
> >> Commit 8c182bd7 ("ACPI: processor: Fix CPU0 wakeup in
> >> acpi_idle_play_dead()") tried to fix CPU0 hotplug breakage by copying
> >> wakeup_cpu0() + start_cpu0() logic from hlt_play_dead()//mwait_play_dead()
> >> into acpi_idle_play_dead(). The problem is that these functions are not
> >> exported to modules so when CONFIG_ACPI_PROCESSOR=m build fails.
> >>
> >> The issue could've been fixed by exporting both wakeup_cpu0()/start_cpu0()
> >> (the later from assembly) but it seems putting the whole pattern into a
> >> new function and exporting it instead is better.
> >>
> >> Reported-by: kernel test robot
> >> Fixes: 8c182bd7 ("CPI: processor: Fix CPU0 wakeup in
> >> acpi_idle_play_dead()")
> >> Cc: # 5.10+
> >> Signed-off-by: Vitaly Kuznetsov
> >> ---
> >> Changes since v1:
> >> - Rename wakeup_cpu0() to cond_wakeup_cpu0() and fold wakeup_cpu0() in
> >> as it has no other users [Rafael J. Wysocki]
> >> ---
> >> arch/x86/include/asm/smp.h| 2 +-
> >> arch/x86/kernel/smpboot.c | 24 ++--
> >> drivers/acpi/processor_idle.c | 4 +---
> >> 3 files changed, 12 insertions(+), 18 deletions(-)
> >>
> >> diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h
> >> index 57ef2094af93..630ff08532be 100644
> >> --- a/arch/x86/include/asm/smp.h
> >> +++ b/arch/x86/include/asm/smp.h
> >> @@ -132,7 +132,7 @@ void native_play_dead(void);
> >> void play_dead_common(void);
> >> void wbinvd_on_cpu(int cpu);
> >> int wbinvd_on_all_cpus(void);
> >> -bool wakeup_cpu0(void);
> >> +void cond_wakeup_cpu0(void);
> >>
> >> void native_smp_send_reschedule(int cpu);
> >> void native_send_call_func_ipi(const struct cpumask *mask);
> >> diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
> >> index f877150a91da..147f1bba9736 100644
> >> --- a/arch/x86/kernel/smpboot.c
> >> +++ b/arch/x86/kernel/smpboot.c
> >> @@ -1659,13 +1659,15 @@ void play_dead_common(void)
> >> local_irq_disable();
> >> }
> >>
> >> -bool wakeup_cpu0(void)
> >> +/*
> >> + * If NMI wants to wake up CPU0, start CPU0.
> >> + */
> >
> > Hasn't checkpatch.pl complained about this?
> >
>
> No, it didn't.
>
> > A proper kerneldoc would be something like:
> >
> > /**
> > * cond_wakeup_cpu0 - Wake up CPU0 if needed.
> > *
> > * If NMI wants to wake up CPU0, start CPU0.
> > */
>
> Yea, I didn't do that partly because of my laziness but partly because
> I don't see much usage of this format in arch/x86/kernel/[smpboot.c]. I
> can certainly do v3 if it's prefered.
Yes, please.
Exported functions generally need proper kerneldoc comments.
Re: [PATCH v2] ACPI: processor: Fix build when CONFIG_ACPI_PROCESSOR=m
"Rafael J. Wysocki" writes:
> On Tue, Apr 6, 2021 at 4:01 PM Vitaly Kuznetsov wrote:
>>
>> Commit 8c182bd7 ("ACPI: processor: Fix CPU0 wakeup in
>> acpi_idle_play_dead()") tried to fix CPU0 hotplug breakage by copying
>> wakeup_cpu0() + start_cpu0() logic from hlt_play_dead()//mwait_play_dead()
>> into acpi_idle_play_dead(). The problem is that these functions are not
>> exported to modules so when CONFIG_ACPI_PROCESSOR=m build fails.
>>
>> The issue could've been fixed by exporting both wakeup_cpu0()/start_cpu0()
>> (the later from assembly) but it seems putting the whole pattern into a
>> new function and exporting it instead is better.
>>
>> Reported-by: kernel test robot
>> Fixes: 8c182bd7 ("CPI: processor: Fix CPU0 wakeup in
>> acpi_idle_play_dead()")
>> Cc: # 5.10+
>> Signed-off-by: Vitaly Kuznetsov
>> ---
>> Changes since v1:
>> - Rename wakeup_cpu0() to cond_wakeup_cpu0() and fold wakeup_cpu0() in
>> as it has no other users [Rafael J. Wysocki]
>> ---
>> arch/x86/include/asm/smp.h| 2 +-
>> arch/x86/kernel/smpboot.c | 24 ++--
>> drivers/acpi/processor_idle.c | 4 +---
>> 3 files changed, 12 insertions(+), 18 deletions(-)
>>
>> diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h
>> index 57ef2094af93..630ff08532be 100644
>> --- a/arch/x86/include/asm/smp.h
>> +++ b/arch/x86/include/asm/smp.h
>> @@ -132,7 +132,7 @@ void native_play_dead(void);
>> void play_dead_common(void);
>> void wbinvd_on_cpu(int cpu);
>> int wbinvd_on_all_cpus(void);
>> -bool wakeup_cpu0(void);
>> +void cond_wakeup_cpu0(void);
>>
>> void native_smp_send_reschedule(int cpu);
>> void native_send_call_func_ipi(const struct cpumask *mask);
>> diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
>> index f877150a91da..147f1bba9736 100644
>> --- a/arch/x86/kernel/smpboot.c
>> +++ b/arch/x86/kernel/smpboot.c
>> @@ -1659,13 +1659,15 @@ void play_dead_common(void)
>> local_irq_disable();
>> }
>>
>> -bool wakeup_cpu0(void)
>> +/*
>> + * If NMI wants to wake up CPU0, start CPU0.
>> + */
>
> Hasn't checkpatch.pl complained about this?
>
No, it didn't.
> A proper kerneldoc would be something like:
>
> /**
> * cond_wakeup_cpu0 - Wake up CPU0 if needed.
> *
> * If NMI wants to wake up CPU0, start CPU0.
> */
Yea, I didn't do that partly because of my laziness but partly because
I don't see much usage of this format in arch/x86/kernel/[smpboot.c]. I
can certainly do v3 if it's prefered.
>
>> +void cond_wakeup_cpu0(void)
>> {
>> if (smp_processor_id() == 0 && enable_start_cpu0)
>> - return true;
>> -
>> - return false;
>> + start_cpu0();
>> }
>> +EXPORT_SYMBOL_GPL(cond_wakeup_cpu0);
>>
>> /*
>> * We need to flush the caches before going to sleep, lest we have
>> @@ -1734,11 +1736,8 @@ static inline void mwait_play_dead(void)
>> __monitor(mwait_ptr, 0, 0);
>> mb();
>> __mwait(eax, 0);
>> - /*
>> -* If NMI wants to wake up CPU0, start CPU0.
>> -*/
>> - if (wakeup_cpu0())
>> - start_cpu0();
>> +
>> + cond_wakeup_cpu0();
>> }
>> }
>>
>> @@ -1749,11 +1748,8 @@ void hlt_play_dead(void)
>>
>> while (1) {
>> native_halt();
>> - /*
>> -* If NMI wants to wake up CPU0, start CPU0.
>> -*/
>> - if (wakeup_cpu0())
>> - start_cpu0();
>> +
>> + cond_wakeup_cpu0();
>> }
>> }
>>
>> diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
>> index 768a6b4d2368..4e2d76b8b697 100644
>> --- a/drivers/acpi/processor_idle.c
>> +++ b/drivers/acpi/processor_idle.c
>> @@ -544,9 +544,7 @@ static int acpi_idle_play_dead(struct cpuidle_device
>> *dev, int index)
>> return -ENODEV;
>>
>> #if defined(CONFIG_X86) && defined(CONFIG_HOTPLUG_CPU)
>> - /* If NMI wants to wake up CPU0, start CPU0. */
>> - if (wakeup_cpu0())
>> - start_cpu0();
>> + cond_wakeup_cpu0();
>> #endif
>> }
>>
>> --
>> 2.30.2
>>
>
--
Vitaly
Re: [PATCH v2] ACPI: processor: Fix build when CONFIG_ACPI_PROCESSOR=m
On Tue, Apr 6, 2021 at 4:01 PM Vitaly Kuznetsov wrote:
>
> Commit 8c182bd7 ("ACPI: processor: Fix CPU0 wakeup in
> acpi_idle_play_dead()") tried to fix CPU0 hotplug breakage by copying
> wakeup_cpu0() + start_cpu0() logic from hlt_play_dead()//mwait_play_dead()
> into acpi_idle_play_dead(). The problem is that these functions are not
> exported to modules so when CONFIG_ACPI_PROCESSOR=m build fails.
>
> The issue could've been fixed by exporting both wakeup_cpu0()/start_cpu0()
> (the later from assembly) but it seems putting the whole pattern into a
> new function and exporting it instead is better.
>
> Reported-by: kernel test robot
> Fixes: 8c182bd7 ("CPI: processor: Fix CPU0 wakeup in
> acpi_idle_play_dead()")
> Cc: # 5.10+
> Signed-off-by: Vitaly Kuznetsov
> ---
> Changes since v1:
> - Rename wakeup_cpu0() to cond_wakeup_cpu0() and fold wakeup_cpu0() in
> as it has no other users [Rafael J. Wysocki]
> ---
> arch/x86/include/asm/smp.h| 2 +-
> arch/x86/kernel/smpboot.c | 24 ++--
> drivers/acpi/processor_idle.c | 4 +---
> 3 files changed, 12 insertions(+), 18 deletions(-)
>
> diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h
> index 57ef2094af93..630ff08532be 100644
> --- a/arch/x86/include/asm/smp.h
> +++ b/arch/x86/include/asm/smp.h
> @@ -132,7 +132,7 @@ void native_play_dead(void);
> void play_dead_common(void);
> void wbinvd_on_cpu(int cpu);
> int wbinvd_on_all_cpus(void);
> -bool wakeup_cpu0(void);
> +void cond_wakeup_cpu0(void);
>
> void native_smp_send_reschedule(int cpu);
> void native_send_call_func_ipi(const struct cpumask *mask);
> diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
> index f877150a91da..147f1bba9736 100644
> --- a/arch/x86/kernel/smpboot.c
> +++ b/arch/x86/kernel/smpboot.c
> @@ -1659,13 +1659,15 @@ void play_dead_common(void)
> local_irq_disable();
> }
>
> -bool wakeup_cpu0(void)
> +/*
> + * If NMI wants to wake up CPU0, start CPU0.
> + */
Hasn't checkpatch.pl complained about this?
A proper kerneldoc would be something like:
/**
* cond_wakeup_cpu0 - Wake up CPU0 if needed.
*
* If NMI wants to wake up CPU0, start CPU0.
*/
> +void cond_wakeup_cpu0(void)
> {
> if (smp_processor_id() == 0 && enable_start_cpu0)
> - return true;
> -
> - return false;
> + start_cpu0();
> }
> +EXPORT_SYMBOL_GPL(cond_wakeup_cpu0);
>
> /*
> * We need to flush the caches before going to sleep, lest we have
> @@ -1734,11 +1736,8 @@ static inline void mwait_play_dead(void)
> __monitor(mwait_ptr, 0, 0);
> mb();
> __mwait(eax, 0);
> - /*
> -* If NMI wants to wake up CPU0, start CPU0.
> -*/
> - if (wakeup_cpu0())
> - start_cpu0();
> +
> + cond_wakeup_cpu0();
> }
> }
>
> @@ -1749,11 +1748,8 @@ void hlt_play_dead(void)
>
> while (1) {
> native_halt();
> - /*
> -* If NMI wants to wake up CPU0, start CPU0.
> -*/
> - if (wakeup_cpu0())
> - start_cpu0();
> +
> + cond_wakeup_cpu0();
> }
> }
>
> diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
> index 768a6b4d2368..4e2d76b8b697 100644
> --- a/drivers/acpi/processor_idle.c
> +++ b/drivers/acpi/processor_idle.c
> @@ -544,9 +544,7 @@ static int acpi_idle_play_dead(struct cpuidle_device
> *dev, int index)
> return -ENODEV;
>
> #if defined(CONFIG_X86) && defined(CONFIG_HOTPLUG_CPU)
> - /* If NMI wants to wake up CPU0, start CPU0. */
> - if (wakeup_cpu0())
> - start_cpu0();
> + cond_wakeup_cpu0();
> #endif
> }
>
> --
> 2.30.2
>
