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 <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>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h
index 57ef209..630ff08 100644 (file)
--- 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 5ea5f96..b95d1c5 100644 (file)
--- 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
index 4e30396..fb161a2 100644 (file)
--- 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
        }