[RFC PATCH] crashdump/x86: Add option to get crash kernel region size

[Simon Horman]

On Mon, Nov 30, 2015 at 08:39:31AM +0100, Daniel Kiper wrote:
> On Mon, Nov 30, 2015 at 08:55:32AM +0900, Simon Horman wrote:
> > On Sat, Nov 28, 2015 at 09:14:04PM +0100, Daniel Kiper wrote:
> > > Crash kernel region size is available via sysfs on Linux running on
> > > bare metal. However, this does not work when Linux runs as Xen dom0.
> > > In this case Xen crash kernel region size should be established using
> > > __HYPERVISOR_kexec_op hypercall (Linux kernel kexec functionality does
> > > not make a lot of sense in Xen dom0). Sadly hypercalls are not easily
> > > accessible using shell scripts or something like that. Potentially we
> > > can check "xl dmesg" output for crashkernel option but this is not nice.
> > > So, let's add this functionality, for Linux running on bare metal and
> > > as Xen dom0, to kexec-tools. This way kdump scripts may establish crash
> > > kernel region size in one way regardless of platform. All burden of
> > > platform detection lies on kexec-tools.
> > >
> > > Figure (and unit) displayed by this new kexec-tools functionality is
> > > the same as one taken from /sys/kernel/kexec_crash_size.
> > >
> > > This functionality is available on x86 platform only. If idea is acceptable
> > > then I can prepare patches for other platforms (if it is possible and make
> > > sense) and repost them as fully flagged patch series.
> > >
> > > Signed-off-by: Daniel Kiper <daniel.kiper at oracle.com>
> >
> > Thanks, applied.
> 
> Thanks a lot. However, this patch itself breaks build on other platforms.
> That is why I posted it as a RFC. To fix this I can post similar patches
> for other platforms (this will happen probably tomorrow or on Wednesday
> but no later than by the end of this week). Or you can revert this patch
> and than I repost it as a part of fully functional patch series.

Sorry for being a bit too hasty.

I will revert.