[paulmck-rcu:dev.2023.05.05a 47/72] arch/csky/kernel/smp.c:320:1: warning: 'noreturn' function does return

[kernel test robot <lkp@intel.com>]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git dev.2023.05.05a
head:   e217254079020832da33e19179438f4f5dcf81c8
commit: fb27834418c972c982320994dc42a29cca6df154 [47/72] objtool: Fix for unreachable instruction warning
config: csky-randconfig-r001-20230505 (https://download.01.org/0day-ci/archive/20230506/202305061006.icKxQPqN-lkp@intel.com/config)
compiler: csky-linux-gcc (GCC) 12.1.0
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
        # https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git/commit/?id=fb27834418c972c982320994dc42a29cca6df154
        git remote add paulmck-rcu https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git
        git fetch --no-tags paulmck-rcu dev.2023.05.05a
        git checkout fb27834418c972c982320994dc42a29cca6df154
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=csky olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=csky SHELL=/bin/bash arch/csky/kernel/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Link: https://lore.kernel.org/oe-kbuild-all/202305061006.icKxQPqN-lkp@intel.com/

All warnings (new ones prefixed by >>):

   arch/csky/kernel/smp.c:246:6: warning: no previous prototype for 'csky_start_secondary' [-Wmissing-prototypes]
     246 | void csky_start_secondary(void)
         |      ^~~~~~~~~~~~~~~~~~~~
   arch/csky/kernel/smp.c: In function 'arch_cpu_idle_dead':
>> arch/csky/kernel/smp.c:320:1: warning: 'noreturn' function does return
     320 | }
         | ^


vim +/noreturn +320 arch/csky/kernel/smp.c

859e5f45cbb33f Guo Ren        2018-12-19  302  
859e5f45cbb33f Guo Ren        2018-12-19  303  void arch_cpu_idle_dead(void)
859e5f45cbb33f Guo Ren        2018-12-19  304  {
859e5f45cbb33f Guo Ren        2018-12-19  305  	idle_task_exit();
859e5f45cbb33f Guo Ren        2018-12-19  306  
859e5f45cbb33f Guo Ren        2018-12-19  307  	cpu_report_death();
859e5f45cbb33f Guo Ren        2018-12-19  308  
859e5f45cbb33f Guo Ren        2018-12-19  309  	while (!secondary_stack)
859e5f45cbb33f Guo Ren        2018-12-19  310  		arch_cpu_idle();
859e5f45cbb33f Guo Ren        2018-12-19  311  
89b3098703bd2a Peter Zijlstra 2023-01-12  312  	raw_local_irq_disable();
859e5f45cbb33f Guo Ren        2018-12-19  313  
859e5f45cbb33f Guo Ren        2018-12-19  314  	asm volatile(
859e5f45cbb33f Guo Ren        2018-12-19  315  		"mov	sp, %0\n"
859e5f45cbb33f Guo Ren        2018-12-19  316  		"mov	r8, %0\n"
859e5f45cbb33f Guo Ren        2018-12-19  317  		"jmpi	csky_start_secondary"
859e5f45cbb33f Guo Ren        2018-12-19  318  		:
859e5f45cbb33f Guo Ren        2018-12-19  319  		: "r" (secondary_stack));
859e5f45cbb33f Guo Ren        2018-12-19 @320  }

:::::: The code at line 320 was first introduced by commit
:::::: 859e5f45cbb33fe5d591a8e429667f0b7d4f4be8 csky: CPU-hotplug supported for SMP

:::::: TO: Guo Ren <ren_guo@c-sky.com>
:::::: CC: Guo Ren <ren_guo@c-sky.com>

-- 
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https://github.com/intel/lkp-tests