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ACPI: processor: Fix build when CONFIG_ACPI_PROCESSOR=m

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Commit 8cdddd182b ("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: 8cdddd182b ("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>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Vitaly Kuznetsov 2021-04-06 17:56:40 +02:00 committed by Rafael J. Wysocki
parent e49d033bdd
commit fa26d0c778
3 changed files with 14 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/x86/include/asm/smp.h
View File

@ -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);

26
arch/x86/kernel/smpboot.c
View File

@ -1659,13 +1659,17 @@ void play_dead_common(void)
local_irq_disable();
}
bool wakeup_cpu0(void)
/**
* 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 +1738,8 @@ 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 +1750,8 @@ 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();
}
}

4
drivers/acpi/processor_idle.c
View File

@ -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
}