[s390:for-next 7/9] arch/s390/kernel/signal.c:464:6: warning: no previous prototype for 'arch_do_signal_or_restart'

[kernel test robot <lkp@xxxxxxxxx>]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/s390/linux.git for-next
head:   3a790cc1c9ef1b7b613cf648e6fb756a842caa16
commit: 56e62a73702836017564eaacd5212e4d0fa1c01d [7/9] s390: convert to generic entry
config: s390-allyesconfig (attached as .config)
compiler: s390-linux-gcc (GCC) 9.3.0
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/s390/linux.git/commit/?id=56e62a73702836017564eaacd5212e4d0fa1c01d
        git remote add s390 https://git.kernel.org/pub/scm/linux/kernel/git/s390/linux.git
        git fetch --no-tags s390 for-next
        git checkout 56e62a73702836017564eaacd5212e4d0fa1c01d
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=s390 

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

All warnings (new ones prefixed by >>):

>> arch/s390/kernel/signal.c:464:6: warning: no previous prototype for 'arch_do_signal_or_restart' [-Wmissing-prototypes]
     464 | void arch_do_signal_or_restart(struct pt_regs *regs, bool has_signal)
         |      ^~~~~~~~~~~~~~~~~~~~~~~~~


vim +/arch_do_signal_or_restart +464 arch/s390/kernel/signal.c

   453	
   454	/*
   455	 * Note that 'init' is a special process: it doesn't get signals it doesn't
   456	 * want to handle. Thus you cannot kill init even with a SIGKILL even by
   457	 * mistake.
   458	 *
   459	 * Note that we go through the signals twice: once to check the signals that
   460	 * the kernel can handle, and then we build all the user-level signal handling
   461	 * stack-frames in one go after that.
   462	 */
   463	
 > 464	void arch_do_signal_or_restart(struct pt_regs *regs, bool has_signal)
   465	{
   466		struct ksignal ksig;
   467		sigset_t *oldset = sigmask_to_save();
   468	
   469		/*
   470		 * Get signal to deliver. When running under ptrace, at this point
   471		 * the debugger may change all our registers, including the system
   472		 * call information.
   473		 */
   474		current->thread.system_call =
   475			test_pt_regs_flag(regs, PIF_SYSCALL) ? regs->int_code : 0;
   476	
   477		if (has_signal && get_signal(&ksig)) {
   478			/* Whee!  Actually deliver the signal.  */
   479			if (current->thread.system_call) {
   480				regs->int_code = current->thread.system_call;
   481				/* Check for system call restarting. */
   482				switch (regs->gprs[2]) {
   483				case -ERESTART_RESTARTBLOCK:
   484				case -ERESTARTNOHAND:
   485					regs->gprs[2] = -EINTR;
   486					break;
   487				case -ERESTARTSYS:
   488					if (!(ksig.ka.sa.sa_flags & SA_RESTART)) {
   489						regs->gprs[2] = -EINTR;
   490						break;
   491					}
   492					fallthrough;
   493				case -ERESTARTNOINTR:
   494					regs->gprs[2] = regs->orig_gpr2;
   495					regs->psw.addr =
   496						__rewind_psw(regs->psw,
   497							     regs->int_code >> 16);
   498					break;
   499				}
   500			}
   501			/* No longer in a system call */
   502			clear_pt_regs_flag(regs, PIF_SYSCALL);
   503			clear_pt_regs_flag(regs, PIF_SYSCALL_RESTART);
   504			rseq_signal_deliver(&ksig, regs);
   505			if (is_compat_task())
   506				handle_signal32(&ksig, oldset, regs);
   507			else
   508				handle_signal(&ksig, oldset, regs);
   509			return;
   510		}
   511	
   512		/* No handlers present - check for system call restart */
   513		clear_pt_regs_flag(regs, PIF_SYSCALL);
   514		clear_pt_regs_flag(regs, PIF_SYSCALL_RESTART);
   515		if (current->thread.system_call) {
   516			regs->int_code = current->thread.system_call;
   517			switch (regs->gprs[2]) {
   518			case -ERESTART_RESTARTBLOCK:
   519				/* Restart with sys_restart_syscall */
   520				regs->int_code = __NR_restart_syscall;
   521				fallthrough;
   522			case -ERESTARTNOHAND:
   523			case -ERESTARTSYS:
   524			case -ERESTARTNOINTR:
   525				/* Restart system call with magic TIF bit. */
   526				regs->gprs[2] = regs->orig_gpr2;
   527				set_pt_regs_flag(regs, PIF_SYSCALL_RESTART);
   528				if (test_thread_flag(TIF_SINGLE_STEP))
   529					clear_thread_flag(TIF_PER_TRAP);
   530				break;
   531			}
   532		}
   533	
   534		/*
   535		 * If there's no signal to deliver, we just put the saved sigmask back.
   536		 */
   537		restore_saved_sigmask();
   538	}
   539	

---
0-DAY CI Kernel Test Service, Intel Corporation
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