Re: [PATCH 6/9] s390/bug: Implement __WARN_printf()

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

Hi Heiko,

kernel test robot noticed the following build warnings:

[auto build test WARNING on 70075e3d0ca0b72cc983d03f7cd9796e43492980]

url:    https://github.com/intel-lab-lkp/linux/commits/Heiko-Carstens/kbuild-Require-gcc-9-for-s390/20251209-202647
base:   70075e3d0ca0b72cc983d03f7cd9796e43492980
patch link:    https://lore.kernel.org/r/20251209121701.1856271-7-hca%40linux.ibm.com
patch subject: [PATCH 6/9] s390/bug: Implement __WARN_printf()
config: s390-randconfig-r062-20251210 (https://download.01.org/0day-ci/archive/20251210/202512102049.3FCpsgLh-lkp@intel.com/config)
compiler: s390-linux-gcc (GCC) 14.3.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251210/202512102049.3FCpsgLh-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202512102049.3FCpsgLh-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> arch/s390/kernel/traps.c:224:26: warning: 'struct arch_va_list' declared inside parameter list will not be visible outside of this definition or declaration
     224 | void *__warn_args(struct arch_va_list *args, struct pt_regs *regs)
         |                          ^~~~~~~~~~~~
>> arch/s390/kernel/traps.c:224:7: warning: no previous prototype for '__warn_args' [-Wmissing-prototypes]
     224 | void *__warn_args(struct arch_va_list *args, struct pt_regs *regs)
         |       ^~~~~~~~~~~
   arch/s390/kernel/traps.c: In function '__warn_args':
   arch/s390/kernel/traps.c:243:13: error: invalid use of undefined type 'struct arch_va_list'
     243 |         args->__overflow_arg_area = stack_frame + 1;
         |             ^~
   arch/s390/kernel/traps.c:244:13: error: invalid use of undefined type 'struct arch_va_list'
     244 |         args->__reg_save_area = regs->gprs;
         |             ^~
   arch/s390/kernel/traps.c:245:13: error: invalid use of undefined type 'struct arch_va_list'
     245 |         args->__gpr = 1;
         |             ^~


vim +224 arch/s390/kernel/traps.c

   223	
 > 224	void *__warn_args(struct arch_va_list *args, struct pt_regs *regs)
   225	{
   226		struct stack_frame *stack_frame;
   227	
   228		/*
   229		 * Generate va_list from pt_regs. See ELF Application Binary Interface
   230		 * s390x Supplement documentation for details.
   231		 *
   232		 * - __overflow_arg_area needs to point to the parameter area, which
   233		 *   is right above the standard stack frame (160 bytes)
   234		 *
   235		 * - __reg_save_area needs to point to a register save area where
   236		 *   general registers (%r2 - %r6) can be found at offset 16. Which
   237		 *   means that the gprs save area of pt_regs can be used
   238		 *
   239		 * - __gpr must be set to one, since the first parameter has been
   240		 *   processed (pointer to bug_entry)
   241		 */
   242		stack_frame = (struct stack_frame *)regs->gprs[15];
   243		args->__overflow_arg_area = stack_frame + 1;
   244		args->__reg_save_area = regs->gprs;
   245		args->__gpr = 1;
   246		return args;
   247	}
   248	

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