Re: [PATCH] kexec jump: fix code size checking

Vivek Goyal
2008-08-13T13:22:54Z

On Wed, Aug 13, 2008 at 11:05:15AM +0800, Huang Ying wrote:
> On Wed, 2008-08-13 at 12:47 +1000, Simon Horman wrote:
> > On Wed, Aug 13, 2008 at 09:04:35AM +0800, Huang Ying wrote:
> > > Fix building issue when CONFIG_KEXEC=n. Thanks to Vivek Goyal for his
> > > reminding.
> > >
> > > Signed-off-by: Huang Ying <ying.huang@intel.com>
> > >
> > > ---
> > > include/asm-x86/kexec.h | 3 +++
> > > 1 file changed, 3 insertions(+)
> > >
> > > --- a/include/asm-x86/kexec.h
> > > +++ b/include/asm-x86/kexec.h
> > > @@ -43,6 +43,9 @@
> > >
> > > #ifdef CONFIG_X86_32
> > > # define KEXEC_CONTROL_CODE_MAX_SIZE 2048
> > > +# ifndef CONFIG_KEXEC
> > > +# define kexec_control_code_size 0
> > > +# endif
> > > #endif
> > >
> > > #ifndef __ASSEMBLY__
> >
> > Is it impossible to skip the linker check in the !CONFIG_KEXEC case?
>
> It is possible. I think there are several ways to do that.
>
> 1) use #ifdef in vmlinux_32.lds.S, such as:
>
> #ifdef CONFIG_KEXEC
> ASSERT(kexec_control_code_size <= KEXEC_CONTROL_CODE_MAX_SIZE,
> "kexec control code size is too big")
> #endif
>
> 2) #define a macro for kexec check ld script in asm/kexec.h, such as:
>
> #define LD_CHECK_KEXEC() ASSERT(kexec_control_code_size <= KEXEC_CONTROL_CODE_MAX_SIZE, \
> "kexec control code size is too big")
>
> and use that in vmlinux_32.lds.S.
>
> 3) #define kexec_control_code_size 0. So that the check can be passed
> always. And, code size = 0 is reasonable for no code (CONFIG_KEXEC=n).
>
>
> I think 3) is better. What do you think about?
>

I think 1) is good enough.

Thanks
Vivek