Re: [PATCH 1/1] X86: mshyperv.c: Fix a compilation issue.

[Greg KH <gregkh@linuxfoundation.org>]

On Thu, Aug 06, 2015 at 02:41:24PM -0700, K. Y. Srinivasan wrote:
> Building with a random configuration file, this build failure
> was reported:
> 
> arch/x86/built-in.o: In function `hv_machine_crash_shutdown':
> arch/x86/kernel/cpu/mshyperv.c:112: undefined
> reference to `native_machine_crash_shutdown'
> 
> This patch fixes the problem
> 
> Reported-by: Jim Davis <jim.epost@gmail.com>
> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
> ---
>  arch/x86/kernel/cpu/mshyperv.c |    2 ++
>  1 files changed, 2 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
> index f794bfa..0faed5e0 100644
> --- a/arch/x86/kernel/cpu/mshyperv.c
> +++ b/arch/x86/kernel/cpu/mshyperv.c
> @@ -109,7 +109,9 @@ static void hv_machine_crash_shutdown(struct pt_regs *regs)
>  {
>  	if (hv_crash_handler)
>  		hv_crash_handler(regs);
> +#ifdef CONFIG_KEXEC_CORE
>  	native_machine_crash_shutdown(regs);
> +#endif

Why is kexec the factor here?  And if it really does, can't it just be
CONFIG_KEXEC, or, can kexec provide a "dummy" inline function so that
you don't have to have a #ifdef in a .c file?

thanks,

greg k-h