[PATCH v2 00/12] crashdump: Add print_crashkernel_region_size() function

[Pratyush Anand]

On Tuesday 07 February 2017 01:12 AM, Eric DeVolder 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 patch just adds print_crashkernel_region_size() function, which
> prints crash kernel region size, for x86 arch. Next patches will add
> same named function for other archs supported by kexec-tools. Last patch
> of this series will export this functionality to the userspace via
> separate kexec utility option.

IMHO, overall code would have been more cleaner if we introduce 
get_crash_kernel_load_range() for each arch. Then a single function to 
get_crash_kernel_size() in kexec/kexec.c.

~Pratyush