[PATCH v4 5/5] kexec: document -s, -c and -a options.

[Michal Suchánek]

On Wed, 14 Mar 2018 11:41:30 +0800
Dave Young <dyoung at redhat.com> wrote:

> On 03/06/18 at 02:15pm, Michal Suchanek wrote:
> > Signed-off-by: Michal Suchanek <msuchanek at suse.de>
> > ---
> >  kexec/kexec.8 | 15 +++++++++++++++
> >  1 file changed, 15 insertions(+)
> > 
> > diff --git a/kexec/kexec.8 b/kexec/kexec.8
> > index e0131b4ea827..b3543db3f413 100644
> > --- a/kexec/kexec.8
> > +++ b/kexec/kexec.8
> > @@ -144,6 +144,21 @@ Load the new kernel for use on panic.
> >  Specify that the new kernel is of this
> >  .I type.
> >  .TP
> > +.BI \-s\ (\-\-kexec-file-syscall)
> > +Specify that the new KEXEC_FILE_LOAD syscall should be used
> > exclusively.  
> 
> Maybe better to be simple like below:
> "Use kexec_file_load syscall to load the new kernel."
> 
> 
> > +.TP
> > +.BI \-c\ (\-\-kexec-syscall)
> > +Specify that the old KEXEC_LOAD syscall should be used exclusively
> > (the default).  
> 
> similarly:
> "Use kexec_load syscall to load the new kernel."
> 
> > +.TP
> > +.BI \-a\ (\-\-kexec-syscall-auto)
> > +Try the new simpler KEXEC_FILE_LOAD syscall first and if it is not
> > supported +fall back to the old KEXEC_LOAD interface.
> > +
> > +There is no one single interface that always works.
> > KEXEC_FILE_LOAD is required +on systems that use locked-down secure
> > boot to verify the kernel signature. +KEXEC_LOAD is required for
> > some kernel image formats and on architectures that +do not support
> > KEXEC_FILE_LOAD.  
> 
> It seems not good to say kexec_file_load is simpler and newer.  Also
> it is not a must for Secure Boot and locked down kernel only. So it
> would be better to just simplify and use the first paragraph:
> 
> "Try kexec_file_load syscall first and if it is not supported fall
> back to the kexec_load syscall"

There was a request for explanation so just the first paragraph will
not do. What is it required for other than secure boot?

Thanks

Michal