ACPI: processor: Fix build when CONFIG_ACPI_PROCESSOR=m

commit fa26d0c778b432d3d9814ea82552e813b33eeb5c upstream. 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 <[email protected]> Fixes: 8cdddd182bd7 ("CPI: processor: Fix CPU0 wakeup in acpi_idle_play_dead()") Cc: <[email protected]> # 5.10+ Signed-off-by: Vitaly Kuznetsov <[email protected]> Signed-off-by: Rafael J. Wysocki <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
sourajitk · Apr 14, 2021 · 856f60e · 856f60e
1 parent 8599a39
commit 856f60e
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Showing 3 changed files with 14 additions and 18 deletions.
diff --git 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
@@ -1655,13 +1655,17 @@ 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
@@ -1730,11 +1734,8 @@ 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();
 	}
 }
 
@@ -1745,11 +1746,8 @@ 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
@@ -545,9 +545,7 @@ 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
 	}