* [PATCH] ACPI: processor: Fix build when CONFIG_ACPI_PROCESSOR=m
@ 2021-04-06 12:50 Vitaly Kuznetsov
2021-04-06 13:22 ` Rafael J. Wysocki
0 siblings, 1 reply; 3+ messages in thread
From: Vitaly Kuznetsov @ 2021-04-06 12:50 UTC (permalink / raw)
To: linux-acpi, Rafael J. Wysocki
Cc: x86, Len Brown, Thomas Gleixner, Ingo Molnar, Borislav Petkov,
H. Peter Anvin, stable, kernel test robot, linux-kernel
Commit 8cdddd182bd7 ("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 <lkp@intel.com>
Fixes: 8cdddd182bd7 ("CPI: processor: Fix CPU0 wakeup in acpi_idle_play_dead()")
Cc: <stable@vger.kernel.org> # 5.10+
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
arch/x86/include/asm/smp.h | 2 +-
arch/x86/kernel/smpboot.c | 15 ++++++++++-----
drivers/acpi/processor_idle.c | 3 +--
3 files changed, 12 insertions(+), 8 deletions(-)
diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h
index 57ef2094af93..6f79deb1f970 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 wakeup_cpu0_if_needed(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..9547d870ee27 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1659,7 +1659,7 @@ void play_dead_common(void)
local_irq_disable();
}
-bool wakeup_cpu0(void)
+static bool wakeup_cpu0(void)
{
if (smp_processor_id() == 0 && enable_start_cpu0)
return true;
@@ -1667,6 +1667,13 @@ bool wakeup_cpu0(void)
return false;
}
+void wakeup_cpu0_if_needed(void)
+{
+ if (wakeup_cpu0())
+ start_cpu0();
+}
+EXPORT_SYMBOL_GPL(wakeup_cpu0_if_needed);
+
/*
* We need to flush the caches before going to sleep, lest we have
* dirty data in our caches when we come back up.
@@ -1737,8 +1744,7 @@ static inline void mwait_play_dead(void)
/*
* If NMI wants to wake up CPU0, start CPU0.
*/
- if (wakeup_cpu0())
- start_cpu0();
+ wakeup_cpu0_if_needed();
}
}
@@ -1752,8 +1758,7 @@ void hlt_play_dead(void)
/*
* If NMI wants to wake up CPU0, start CPU0.
*/
- if (wakeup_cpu0())
- start_cpu0();
+ wakeup_cpu0_if_needed();
}
}
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 768a6b4d2368..de15116b754a 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -545,8 +545,7 @@ static int acpi_idle_play_dead(struct cpuidle_device *dev, int index)
#if defined(CONFIG_X86) && defined(CONFIG_HOTPLUG_CPU)
/* If NMI wants to wake up CPU0, start CPU0. */
- if (wakeup_cpu0())
- start_cpu0();
+ wakeup_cpu0_if_needed();
#endif
}
--
2.30.2
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] ACPI: processor: Fix build when CONFIG_ACPI_PROCESSOR=m
2021-04-06 12:50 [PATCH] ACPI: processor: Fix build when CONFIG_ACPI_PROCESSOR=m Vitaly Kuznetsov
@ 2021-04-06 13:22 ` Rafael J. Wysocki
2021-04-06 13:37 ` Vitaly Kuznetsov
0 siblings, 1 reply; 3+ messages in thread
From: Rafael J. Wysocki @ 2021-04-06 13:22 UTC (permalink / raw)
To: Vitaly Kuznetsov
Cc: ACPI Devel Maling List, Rafael J. Wysocki,
the arch/x86 maintainers, Len Brown, Thomas Gleixner,
Ingo Molnar, Borislav Petkov, H. Peter Anvin, Stable,
kernel test robot, Linux Kernel Mailing List
On Tue, Apr 6, 2021 at 2:50 PM Vitaly Kuznetsov <vkuznets@redhat.com> wrote:
>
> Commit 8cdddd182bd7 ("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 <lkp@intel.com>
> Fixes: 8cdddd182bd7 ("CPI: processor: Fix CPU0 wakeup in acpi_idle_play_dead()")
> Cc: <stable@vger.kernel.org> # 5.10+
> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
> ---
> arch/x86/include/asm/smp.h | 2 +-
> arch/x86/kernel/smpboot.c | 15 ++++++++++-----
> drivers/acpi/processor_idle.c | 3 +--
> 3 files changed, 12 insertions(+), 8 deletions(-)
>
> diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h
> index 57ef2094af93..6f79deb1f970 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 wakeup_cpu0_if_needed(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..9547d870ee27 100644
> --- a/arch/x86/kernel/smpboot.c
> +++ b/arch/x86/kernel/smpboot.c
> @@ -1659,7 +1659,7 @@ void play_dead_common(void)
> local_irq_disable();
> }
>
> -bool wakeup_cpu0(void)
> +static bool wakeup_cpu0(void)
> {
> if (smp_processor_id() == 0 && enable_start_cpu0)
> return true;
> @@ -1667,6 +1667,13 @@ bool wakeup_cpu0(void)
> return false;
> }
>
> +void wakeup_cpu0_if_needed(void)
> +{
> + if (wakeup_cpu0())
> + start_cpu0();
Note that all of the callers of wakeup_cpu0 do the above, so maybe
make them all use the new function?
In which case it can be rewritten in the following way
void cond_wakeup_cpu0(void)
{
if (smp_processor_id() == 0 && enable_start_cpu0)
start_cpu0();
}
EXPORT_SYMBOL_GPL(cond_wakeup_cpu0);
Also please add a proper kerneldoc comment to it and maybe drop the
comments at the call sites?
> +}
> +EXPORT_SYMBOL_GPL(wakeup_cpu0_if_needed);
> +
> /*
> * We need to flush the caches before going to sleep, lest we have
> * dirty data in our caches when we come back up.
> @@ -1737,8 +1744,7 @@ static inline void mwait_play_dead(void)
> /*
> * If NMI wants to wake up CPU0, start CPU0.
> */
> - if (wakeup_cpu0())
> - start_cpu0();
> + wakeup_cpu0_if_needed();
> }
> }
>
> @@ -1752,8 +1758,7 @@ void hlt_play_dead(void)
> /*
> * If NMI wants to wake up CPU0, start CPU0.
> */
> - if (wakeup_cpu0())
> - start_cpu0();
> + wakeup_cpu0_if_needed();
> }
> }
>
> diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
> index 768a6b4d2368..de15116b754a 100644
> --- a/drivers/acpi/processor_idle.c
> +++ b/drivers/acpi/processor_idle.c
> @@ -545,8 +545,7 @@ static int acpi_idle_play_dead(struct cpuidle_device *dev, int index)
>
> #if defined(CONFIG_X86) && defined(CONFIG_HOTPLUG_CPU)
> /* If NMI wants to wake up CPU0, start CPU0. */
> - if (wakeup_cpu0())
> - start_cpu0();
> + wakeup_cpu0_if_needed();
> #endif
> }
>
> --
> 2.30.2
>
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] ACPI: processor: Fix build when CONFIG_ACPI_PROCESSOR=m
2021-04-06 13:22 ` Rafael J. Wysocki
@ 2021-04-06 13:37 ` Vitaly Kuznetsov
0 siblings, 0 replies; 3+ messages in thread
From: Vitaly Kuznetsov @ 2021-04-06 13:37 UTC (permalink / raw)
To: Rafael J. Wysocki
Cc: ACPI Devel Maling List, Rafael J. Wysocki,
the arch/x86 maintainers, Len Brown, Thomas Gleixner,
Ingo Molnar, Borislav Petkov, H. Peter Anvin, Stable,
kernel test robot, Linux Kernel Mailing List
"Rafael J. Wysocki" <rafael@kernel.org> writes:
> On Tue, Apr 6, 2021 at 2:50 PM Vitaly Kuznetsov <vkuznets@redhat.com> wrote:
>>
>> Commit 8cdddd182bd7 ("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 <lkp@intel.com>
>> Fixes: 8cdddd182bd7 ("CPI: processor: Fix CPU0 wakeup in acpi_idle_play_dead()")
>> Cc: <stable@vger.kernel.org> # 5.10+
>> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
>> ---
>> arch/x86/include/asm/smp.h | 2 +-
>> arch/x86/kernel/smpboot.c | 15 ++++++++++-----
>> drivers/acpi/processor_idle.c | 3 +--
>> 3 files changed, 12 insertions(+), 8 deletions(-)
>>
>> diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h
>> index 57ef2094af93..6f79deb1f970 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 wakeup_cpu0_if_needed(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..9547d870ee27 100644
>> --- a/arch/x86/kernel/smpboot.c
>> +++ b/arch/x86/kernel/smpboot.c
>> @@ -1659,7 +1659,7 @@ void play_dead_common(void)
>> local_irq_disable();
>> }
>>
>> -bool wakeup_cpu0(void)
>> +static bool wakeup_cpu0(void)
>> {
>> if (smp_processor_id() == 0 && enable_start_cpu0)
>> return true;
>> @@ -1667,6 +1667,13 @@ bool wakeup_cpu0(void)
>> return false;
>> }
>>
>> +void wakeup_cpu0_if_needed(void)
>> +{
>> + if (wakeup_cpu0())
>> + start_cpu0();
>
> Note that all of the callers of wakeup_cpu0 do the above, so maybe
> make them all use the new function?
>
> In which case it can be rewritten in the following way
>
> void cond_wakeup_cpu0(void)
> {
> if (smp_processor_id() == 0 && enable_start_cpu0)
> start_cpu0();
> }
> EXPORT_SYMBOL_GPL(cond_wakeup_cpu0);
>
Sure, separate wakeup_cpu0() is no longer needed.
> Also please add a proper kerneldoc comment to it and maybe drop the
> comments at the call sites?
Also a good idea. v2 is coming, thanks!
>
>
>> +}
>> +EXPORT_SYMBOL_GPL(wakeup_cpu0_if_needed);
>> +
>> /*
>> * We need to flush the caches before going to sleep, lest we have
>> * dirty data in our caches when we come back up.
>> @@ -1737,8 +1744,7 @@ static inline void mwait_play_dead(void)
>> /*
>> * If NMI wants to wake up CPU0, start CPU0.
>> */
>> - if (wakeup_cpu0())
>> - start_cpu0();
>> + wakeup_cpu0_if_needed();
>> }
>> }
>>
>> @@ -1752,8 +1758,7 @@ void hlt_play_dead(void)
>> /*
>> * If NMI wants to wake up CPU0, start CPU0.
>> */
>> - if (wakeup_cpu0())
>> - start_cpu0();
>> + wakeup_cpu0_if_needed();
>> }
>> }
>>
>> diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
>> index 768a6b4d2368..de15116b754a 100644
>> --- a/drivers/acpi/processor_idle.c
>> +++ b/drivers/acpi/processor_idle.c
>> @@ -545,8 +545,7 @@ static int acpi_idle_play_dead(struct cpuidle_device *dev, int index)
>>
>> #if defined(CONFIG_X86) && defined(CONFIG_HOTPLUG_CPU)
>> /* If NMI wants to wake up CPU0, start CPU0. */
>> - if (wakeup_cpu0())
>> - start_cpu0();
>> + wakeup_cpu0_if_needed();
>> #endif
>> }
>>
>> --
>> 2.30.2
>>
>
--
Vitaly
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2021-04-06 13:37 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-04-06 12:50 [PATCH] ACPI: processor: Fix build when CONFIG_ACPI_PROCESSOR=m Vitaly Kuznetsov
2021-04-06 13:22 ` Rafael J. Wysocki
2021-04-06 13:37 ` Vitaly Kuznetsov
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).