Re: [PATCH v2 06/18] perf/hw_breakpoint: add arch-independent hw_breakpoint_modify_local()

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

Hi Jinchao,

kernel test robot noticed the following build warnings:

[auto build test WARNING on akpm-mm/mm-everything]

url:    https://github.com/intel-lab-lkp/linux/commits/Jinchao-Wang/mm-ksw-add-build-system-support/20250904-082544
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20250904002126.1514566-7-wangjinchao600%40gmail.com
patch subject: [PATCH v2 06/18] perf/hw_breakpoint: add arch-independent hw_breakpoint_modify_local()
config: sh-randconfig-001-20250905 (https://download.01.org/0day-ci/archive/20250905/202509052351.KuHBWdAF-lkp@intel.com/config)
compiler: sh4-linux-gcc (GCC) 15.1.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250905/202509052351.KuHBWdAF-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/202509052351.KuHBWdAF-lkp@intel.com/

All warnings (new ones prefixed by >>):

   kernel/events/hw_breakpoint.c: In function 'hw_breakpoint_modify_local':
   kernel/events/hw_breakpoint.c:994:16: error: implicit declaration of function 'arch_reinstall_hw_breakpoint'; did you mean 'arch_uninstall_hw_breakpoint'? [-Wimplicit-function-declaration]
     994 |         return arch_reinstall_hw_breakpoint(bp);
         |                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
         |                arch_uninstall_hw_breakpoint
   kernel/events/hw_breakpoint.c: At top level:
>> kernel/events/hw_breakpoint.c:999:12: warning: no previous prototype for 'arch_reinstall_hw_breakpoint' [-Wmissing-prototypes]
     999 | __weak int arch_reinstall_hw_breakpoint(struct perf_event *bp)
         |            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~


vim +/arch_reinstall_hw_breakpoint +999 kernel/events/hw_breakpoint.c

   997	
   998	/* weak fallback for arches without support */
 > 999	__weak int arch_reinstall_hw_breakpoint(struct perf_event *bp)
  1000	{
  1001		return -EOPNOTSUPP;
  1002	}
  1003	

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