On Mon, Sep 25, 2017 at 04:03:13PM +0800, Dave Young wrote:
> HI AKASHI,
> On 09/22/17 at 04:58pm, AKASHI Takahiro wrote:
> > Hi Dave,
> >
> [snip]
>
> > > > /*
> > > > * Apply purgatory relocations.
> > > > *
> > > > diff --git a/include/linux/kexec.h b/include/linux/kexec.h
> > > > index dd056fab9e35..4a2b24d94e04 100644
> > > > --- a/include/linux/kexec.h
> > > > +++ b/include/linux/kexec.h
> > > > @@ -134,6 +134,26 @@ struct kexec_file_ops {
> > > > #endif
> > > > };
> > > >
> > > > +int kexec_kernel_image_probe(struct kimage *image, void *buf,
> > > > + unsigned long buf_len);
> > > > +void *kexec_kernel_image_load(struct kimage *image);
> > > > +int kexec_kernel_post_load_cleanup(struct kimage *image);
> > > > +int kexec_kernel_verify_sig(struct kimage *image, void *buf,
> > > > + unsigned long buf_len);
> > > > +
> > > > +#ifndef arch_kexec_kernel_image_probe
> > > > +#define arch_kexec_kernel_image_probe kexec_kernel_image_probe
> > > > +#endif
> > > > +#ifndef arch_kexec_kernel_image_load
> > > > +#define arch_kexec_kernel_image_load kexec_kernel_image_load
> > > > +#endif
> > > > +#ifndef arch_kimage_file_post_load_cleanup
> > > > +#define arch_kimage_file_post_load_cleanup kexec_kernel_post_load_cleanup
> > > > +#endif
> > > > +#ifndef arch_kexec_kernel_verify_sig
> > > > +#define arch_kexec_kernel_verify_sig kexec_kernel_verify_sig
> > > > +#endif
> > > > +
> > > > /**
> > > > * struct kexec_buf - parameters for finding a place for a buffer in memory
> > > > * @image: kexec image in which memory to search.
> > > > @@ -276,12 +296,6 @@ int crash_shrink_memory(unsigned long new_size);
> > > > size_t crash_get_memory_size(void);
> > > > void crash_free_reserved_phys_range(unsigned long begin, unsigned long end);
> > > >
> > > > -int __weak arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
> > > > - unsigned long buf_len);
> > > > -void * __weak arch_kexec_kernel_image_load(struct kimage *image);
> > > > -int __weak arch_kimage_file_post_load_cleanup(struct kimage *image);
> > > > -int __weak arch_kexec_kernel_verify_sig(struct kimage *image, void *buf,
> > > > - unsigned long buf_len);
> > >
> > > I thought we can keep using the __weak function in common code and drop
> > > the arch functions, no need the #ifndef arch_kexec_kernel_image_probe
> > > and the function renaming stuff. But I did not notice the powerpc
> > > _probe function checks KEXEC_ON_CRASH, that should be checked earlier
> > > and we can fail out early if not supported, but I have no idea
> > > how to do it gracefully for now.
> > >
> > > Also for x86 _load function it cleanups image->arch.elf_headers, it can
> > > not be dropped simply.
> >
> > Yeah, arm64 post_load_cleanup function also has some extra stuff.
> > See my patch #7/8.
>
> But the x86 cleanup was dropped silently, can you add it in x86
> post_load_cleanup as well?
Sure, I will do.
> >
> > > Consider the above two issues, maybe you can keep the powerpc
> > > version of _probe() and x86 version of _load(), and still copy the common code
> > > to kexec_file.c weak functions.
> >
> > It was exactly what I made before submitting v3, but I changed
> > my mind a bit. My intension is to prevent the code being duplicated
> > even though it has only a few lines of code.
> >
> > I agree that '#ifndef arch_kexec_kernel_image_probe' in kexec.h would be
> > quite ugly, but similar usages can be spotted in the kernel source.
> >
> > That said if you don't like it at all, I defer to you.
>
> I understand your concern, maybe still use a weak function for
> arch_kexec_kernel_image_*, and they call the kexec_kernel_image_* in
> kexec_file.c common code.
>
> Like in general code:
>
> int __weak arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
> unsigned long buf_len)
> {
> return kexec_kernel_image_probe(image, buf, buf_len);
as you suggested,
"return _kexec_kernel_image_probe(...);
would be fine.
-Takahiro AKASHI
> }
>
> In architechture code it can add other code and call
> kexec_kernel_image_*
>
> It looks a bit better than the #ifdef way.
>
> [snip]
>
> >
> > Thanks,
> > -Takahiro AKASHI
> >
>
> Thanks
> Dave
