From: Vitaly Kuznetsov vkuznets@redhat.com
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 --- arch/x86/include/asm/smp.h | 2 +- arch/x86/kernel/smpboot.c | 26 ++++++++++++-------------- drivers/acpi/processor_idle.c | 4 +--- 3 files changed, 14 insertions(+), 18 deletions(-)
--- 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); --- 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(); } }
--- a/drivers/acpi/processor_idle.c +++ b/drivers/acpi/processor_idle.c @@ -545,9 +545,7 @@ static int acpi_idle_play_dead(struct cp 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 }