Re: [PATCH 2/3] [PATCH 2/3] kexec: split kexec_load syscall from kexec core code

[Dave Young <dyoung@redhat.com>]

On 07/14/15 at 10:50am, Geert Uytterhoeven wrote:
> Hi Dave,
> 
> On Tue, Jul 14, 2015 at 10:46 AM, Dave Young <dyoung@redhat.com> wrote:
> >> > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> >> > index 1c50210..20c48b3 100644
> >> > --- a/arch/arm/Kconfig
> >> > +++ b/arch/arm/Kconfig
> >> > @@ -2001,10 +2001,14 @@ config XIP_PHYS_ADDR
> >> >           be linked for and stored to.  This address is dependent on your
> >> >           own flash usage.
> >> >
> >> > +config KEXEC_CORE
> >> > +       bool
> >> > +
> >> >  config KEXEC
> >> >         bool "Kexec system call (EXPERIMENTAL)"
> >> >         depends on (!SMP || PM_SLEEP_SMP)
> >> >         depends on !CPU_V7M
> >> > +       select KEXEC_CORE
> >> >         help
> >> >           kexec is a system call that implements the ability to shutdown your
> >> >           current kernel, and to start another kernel.  It is like a reboot
> >>
> >> As this KEXEC_CORE is appearing in all arch/*/Kconfig files, I think it's
> >> time to add an ARCH_HAS_KEXEC symbol (to a common Kconfig file),
> >> and let arch/*/Kconfig select that if the architecture has kexec support.
> >>
> >> Then KEXEC and KEXEC_CORE can live in the common Kconfig file,
> >> without the need to duplicate it.
> >
> > I'm not sure I understand your idea well, do you means like
> > in arch/Kconfig add ARCH_HAS_KEXEC which depends on KEXEC_CORE?
> 
> No, ARCH_HAS_KEXEC and all other KEXEC config options in arch/Kconfig.
> All other KEXEC config options should depend on ARCH_HAS_KEXEC,
> which can be selected by architectures that support kexec.

So it will be like below? problem is KEXEC_FILE is x86 only now, how
to handle it then?

arch/Kconfig:
config ARCH_HAS_KEXEC
	...
config KEXEC_CORE
	...	
config KEXEC
	...
config KEXEC_FILE
	...

arch/arm/Kconfig:
	select ARCH_HAS_KEXEC 
> 
> > How about simply move below chunk to arch/Kconfig instead of introducing
> > another ARCH_HAS_KEXEC:
> > config KEXEC_CORE
> >         bool
> 
> Not all architectures support kexec, hence my proposed dependency on
> ARCH_HAS_KEXEC.

KEXEC_CORE is not visible in menuconfig, it is selected by KEXEC and KEXEC_FILE
so move it in arch/Kconfig is ok?

> 
> Gr{oetje,eeting}s,
> 
>                         Geert
> 
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
> 
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
>                                 -- Linus Torvalds