Re: [PATCH] x86/apic: Inline __x2apic_send_IPI_dest()

[Eric Dumazet]

On Tue, Dec 23, 2025 at 2:06 AM kernel test robot <lkp@xxxxxxxxx> wrote:
>
> Hi Eric,
>
> kernel test robot noticed the following build errors:
>
> [auto build test ERROR on tip/master]
> [also build test ERROR on tip/x86/core linus/master v6.19-rc2 next-20251219]
> [cannot apply to tip/auto-latest bp/for-next]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch#_base_tree_information]
>
> url:    https://github.com/intel-lab-lkp/linux/commits/Eric-Dumazet/x86-apic-Inline-__x2apic_send_IPI_dest/20251222-172515
> base:   tip/master
> patch link:    https://lore.kernel.org/r/20251222092208.770136-1-edumazet%40google.com
> patch subject: [PATCH] x86/apic: Inline __x2apic_send_IPI_dest()
> config: i386-randconfig-141-20251223 (https://download.01.org/0day-ci/archive/20251223/202512230859.jl2eLtLj-lkp@xxxxxxxxx/config)
> compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251223/202512230859.jl2eLtLj-lkp@xxxxxxxxx/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@xxxxxxxxx>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202512230859.jl2eLtLj-lkp@xxxxxxxxx/
>
> All errors (new ones prefixed by >>):
>
>    In file included from arch/x86/kernel/apic/apic.c:71:
> >> arch/x86/kernel/apic/local.h:48:2: error: call to undeclared function 'native_x2apic_icr_write'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
>       48 |         native_x2apic_icr_write(cfg, apicid);
>          |         ^
>    arch/x86/kernel/apic/local.h:48:2: note: did you mean 'native_apic_icr_write'?
>    arch/x86/include/asm/apic.h:116:13: note: 'native_apic_icr_write' declared here
>      116 | extern void native_apic_icr_write(u32 low, u32 id);
>          |             ^
>    1 error generated.
>
>
> vim +/native_x2apic_icr_write +48 arch/x86/kernel/apic/local.h
>
>     43
>     44  static inline void __x2apic_send_IPI_dest(unsigned int apicid, int vector,
>     45                                            unsigned int dest)
>     46  {
>     47          unsigned long cfg = __prepare_ICR(0, vector, dest);
>   > 48          native_x2apic_icr_write(cfg, apicid);
>     49  }
>     50
>
> --
> 0-DAY CI Kernel Test Service
> https://github.com/intel/lkp-tests/wiki

I missed the CONFIG_X86_X2APIC dependency, thanks !