tree:   https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git bleeding-edge
head:   a70fdf61936ab0200d31bebea4b44bb67454ce07
commit: 5f5e49e999acd8556e694e841d63226d21e409d9 [47/48] ACPI: processor: Fix CPU0 wakeup in acpi_idle_play_dead()
config: x86_64-randconfig-a013-20210329 (attached as .config)
compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 2a28d1d3b7bf2062288b46af34e33ccc543a99fa)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install x86_64 cross compiling tool for clang build
        # apt-get install binutils-x86-64-linux-gnu
        # https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git/commit/?id=5f5e49e999acd8556e694e841d63226d21e409d9
        git remote add pm https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git
        git fetch --no-tags pm bleeding-edge
        git checkout 5f5e49e999acd8556e694e841d63226d21e409d9
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

>> drivers/acpi/processor_idle.c:548:7: error: implicit declaration of function 'wakeup_cpu0' [-Werror,-Wimplicit-function-declaration]
                   if (wakeup_cpu0())
                       ^
>> drivers/acpi/processor_idle.c:549:4: error: implicit declaration of function 'start_cpu0' [-Werror,-Wimplicit-function-declaration]
                           start_cpu0();
                           ^
   drivers/acpi/processor_idle.c:1103:12: warning: no previous prototype for function 'acpi_processor_ffh_lpi_probe' [-Wmissing-prototypes]
   int __weak acpi_processor_ffh_lpi_probe(unsigned int cpu)
              ^
   drivers/acpi/processor_idle.c:1103:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   int __weak acpi_processor_ffh_lpi_probe(unsigned int cpu)
   ^
   static 
   drivers/acpi/processor_idle.c:1108:12: warning: no previous prototype for function 'acpi_processor_ffh_lpi_enter' [-Wmissing-prototypes]
   int __weak acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi)
              ^
   drivers/acpi/processor_idle.c:1108:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   int __weak acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi)
   ^
   static 
   2 warnings and 2 errors generated.


vim +/wakeup_cpu0 +548 drivers/acpi/processor_idle.c

   524	
   525	/**
   526	 * acpi_idle_play_dead - enters an ACPI state for long-term idle (i.e. off-lining)
   527	 * @dev: the target CPU
   528	 * @index: the index of suggested state
   529	 */
   530	static int acpi_idle_play_dead(struct cpuidle_device *dev, int index)
   531	{
   532		struct acpi_processor_cx *cx = per_cpu(acpi_cstate[index], dev->cpu);
   533	
   534		ACPI_FLUSH_CPU_CACHE();
   535	
   536		while (1) {
   537	
   538			if (cx->entry_method == ACPI_CSTATE_HALT)
   539				safe_halt();
   540			else if (cx->entry_method == ACPI_CSTATE_SYSTEMIO) {
   541				inb(cx->address);
   542				wait_for_freeze();
   543			} else
   544				return -ENODEV;
   545	
   546	#ifdef CONFIG_X86
   547			/* If NMI wants to wake up CPU0, start CPU0. */
 > 548			if (wakeup_cpu0())
 > 549				start_cpu0();
   550	#endif
   551		}
   552	
   553		/* Never reached */
   554		return 0;
   555	}
   556	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org