Commit fa26d0c7 authored by Vitaly Kuznetsov's avatar Vitaly Kuznetsov Committed by Rafael J. Wysocki
Browse files

ACPI: processor: Fix build when CONFIG_ACPI_PROCESSOR=m 



Commit 8cdddd18 ("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: default avatarkernel test robot <lkp@intel.com>
Fixes: 8cdddd18 ("CPI: processor: Fix CPU0 wakeup in acpi_idle_play_dead()")
Cc: <stable@vger.kernel.org> # 5.10+
Signed-off-by: default avatarVitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent e49d033b

arch/x86/include/asm/smp.h

+1 −1
Original line number Diff line number Diff line
@@ -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);

arch/x86/kernel/smpboot.c

+12 −14
Original line number Diff line number Diff line
@@ -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();

	}

}

drivers/acpi/processor_idle.c

+1 −3
Original line number Diff line number Diff line
@@ -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

	}