Re: [PATCH v8 03/13] kexec_file,x86,powerpc: factor out kexec_file_ops functions

From: AKASHI Takahiro
Date: Mon Feb 26 2018 - 05:01:45 EST


On Fri, Feb 23, 2018 at 05:24:59PM +0800, Dave Young wrote:
> Hi AKASHI,
>
> On 02/22/18 at 08:17pm, AKASHI Takahiro wrote:
> > As arch_kexec_kernel_*_{probe,load}(), arch_kimage_file_post_load_cleanup()
> > and arch_kexec_kernel_verify_sg can be parameterized with a kexec_file_ops
> > array and now duplicated among some architectures, let's factor them out.
> >
> > Signed-off-by: AKASHI Takahiro <takahiro.akashi@xxxxxxxxxx>
> > Cc: Dave Young <dyoung@xxxxxxxxxx>
> > Cc: Vivek Goyal <vgoyal@xxxxxxxxxx>
> > Cc: Baoquan He <bhe@xxxxxxxxxx>
> > Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
> > Cc: Thiago Jung Bauermann <bauerman@xxxxxxxxxxxxxxxxxx>
> > ---
> > arch/powerpc/include/asm/kexec.h | 2 +-
> > arch/powerpc/kernel/kexec_elf_64.c | 2 +-
> > arch/powerpc/kernel/machine_kexec_file_64.c | 39 ++------------------
> > arch/x86/include/asm/kexec-bzimage64.h | 2 +-
> > arch/x86/kernel/kexec-bzimage64.c | 2 +-
> > arch/x86/kernel/machine_kexec_64.c | 45 +----------------------
> > include/linux/kexec.h | 15 ++++----
> > kernel/kexec_file.c | 57 +++++++++++++++++++++++++++--
> > 8 files changed, 70 insertions(+), 94 deletions(-)
> >
>
> [snip]
>
> > diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
> > index 990adae52151..a6d14a768b3e 100644
> > --- a/kernel/kexec_file.c
> > +++ b/kernel/kexec_file.c
> > @@ -26,34 +26,83 @@
> > #include <linux/vmalloc.h>
> > #include "kexec_internal.h"
> >
> > +const __weak struct kexec_file_ops * const kexec_file_loaders[] = {NULL};
> > +
> > #ifdef CONFIG_ARCH_HAS_KEXEC_PURGATORY
> > static int kexec_calculate_store_digests(struct kimage *image);
> > #else
> > static int kexec_calculate_store_digests(struct kimage *image) { return 0; };
> > #endif
> >
> > +int _kexec_kernel_image_probe(struct kimage *image, void *buf,
> > + unsigned long buf_len)
> > +{
> > + const struct kexec_file_ops * const *fops;
> > + int ret = -ENOEXEC;
> > +
> > + for (fops = &kexec_file_loaders[0]; *fops && (*fops)->probe; ++fops) {
> > + ret = (*fops)->probe(buf, buf_len);
> > + if (!ret) {
> > + image->fops = *fops;
> > + return ret;
> > + }
> > + }
> > +
> > + return ret;
> > +}
> > +
> > /* Architectures can provide this probe function */
> > int __weak arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
> > unsigned long buf_len)
> > {
> > - return -ENOEXEC;
> > + return _kexec_kernel_image_probe(image, buf, buf_len);
>
>
> I vaguely remember previously I suggest split the _kexec_kernel_image_probe
> because arch code can call them, and common code also use it like above.
> But in your new series I do not find where else calls this function
> except the common code arch_kexec_kernel_image_probe. If nobody use
> them then it is not worth to split them out, it is better to just embed
> them in the __weak functions.

Powerpc's arch_kexec_kernel_image_probe() uses
_kexec_kekrnel_image_probe() as it needs an extra check to rule out
crash dump for now.

Thanks,
-Takahiro AKASHI


> Ditto for other similar functions.
>
> [snip]
>
> Thanks
> Dave