Re: [linux-next:master 10163/12085] arch/arm64/kvm/hyp/nvhe/psci-relay.c:174:28: warning: no previous prototype for function 'kvm_host_psci_cpu_entry'

[Marc Zyngier <maz@kernel.org>]

On 2020-12-10 09:24, kernel test robot wrote:
> tree:
> https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
> master
> head:   2f1d5c77f13fe64497c2e2601605f7d7ec4da9b1
> commit: cdf367192766ad11a03e8d5098556be43b8eb6b0 [10163/12085] KVM:
> arm64: Intercept host's CPU_ON SMCs
> config: arm64-randconfig-r032-20201209 (attached as .config)
> compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project
> 1968804ac726e7674d5de22bc2204b45857da344)
> 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
>         # install arm64 cross compiling tool for clang build
>         # apt-get install binutils-aarch64-linux-gnu
>         #
> https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=cdf367192766ad11a03e8d5098556be43b8eb6b0
>         git remote add linux-next
> https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
>         git fetch --no-tags linux-next master
>         git checkout cdf367192766ad11a03e8d5098556be43b8eb6b0
>         # save the attached .config to linux build tree
>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross 
> ARCH=arm64
> 
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
> 
> All warnings (new ones prefixed by >>):
> 
>>> arch/arm64/kvm/hyp/nvhe/psci-relay.c:174:28: warning: no previous 
>>> prototype for function 'kvm_host_psci_cpu_entry' 
>>> [-Wmissing-prototypes]
>    asmlinkage void __noreturn kvm_host_psci_cpu_entry(bool is_cpu_on)
>                               ^
>    arch/arm64/kvm/hyp/nvhe/psci-relay.c:174:12: note: declare 'static'
> if the function is not intended to be used outside of this translation
> unit
>    asmlinkage void __noreturn kvm_host_psci_cpu_entry(bool is_cpu_on)
>               ^
>               static
>    1 warning generated.

I wish someone would fix these reports and weed out these false 
positive.

The function is annotated as  asmlinkage, meaning it is called from some
assembly code. Not amount of prototyping is going to help the assembler,
and making it static is just going to break the build.

Thanks,

         M.

> 
> vim +/kvm_host_psci_cpu_entry +174 arch/arm64/kvm/hyp/nvhe/psci-relay.c
> 
>    173
>  > 174	asmlinkage void __noreturn kvm_host_psci_cpu_entry(bool 
> is_cpu_on)
>    175	{
>    176		struct psci_boot_args *boot_args;
>    177		struct kvm_cpu_context *host_ctxt;
>    178
>    179		host_ctxt = 
> &this_cpu_ptr(hyp_symbol_addr(kvm_host_data))->host_ctxt;
>    180		boot_args = this_cpu_ptr(hyp_symbol_addr(cpu_on_args));
>    181
>    182		cpu_reg(host_ctxt, 0) = boot_args->r0;
>    183		write_sysreg_el2(boot_args->pc, SYS_ELR);
>    184		release_boot_args(boot_args);
>    185
>    186		__host_enter(host_ctxt);
>    187	}
>    188
> 
> ---
> 0-DAY CI Kernel Test Service, Intel Corporation
> https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

-- 
Jazz is not dead. It just smells funny...