[PATCH v2] s390/kexec: Consolidate crash_map/unmap_reserved_pages() and arch_kexec_protect(unprotect)_crashkres()

Xunlei Pang xpang at redhat.com
Tue Apr 5 03:23:31 PDT 2016

On 2016/04/05 at 17:13, Michael Holzheu wrote:
> Hello Xunlei,
> On Tue,  5 Apr 2016 15:09:59 +0800
> Xunlei Pang <xlpang at redhat.com> wrote:
>> Commit 3f625002581b ("kexec: introduce a protection mechanism
>> for the crashkernel reserved memory") is a similar mechanism
>> for protecting the crash kernel reserved memory to previous
>> crash_map/unmap_reserved_pages() implementation, the new one
>> is more generic in name and cleaner in code (besides, some
>> arch may not be allowed to unmap the pgtable).
>> Therefore, this patch consolidates them, and uses the new
>> arch_kexec_protect(unprotect)_crashkres() to replace former
>> crash_map/unmap_reserved_pages() which by now has been only
>> used by S390.
>> The consolidation work needs the crash memory to be mapped
>> initially, so get rid of S390 crash kernel memblock removal
>> in reserve_crashkernel().

Oops, the final paragraph of the changelog should be changed to:
The consolidation work needs the crash memory to be mapped
initially, this is done in machine_kdump_pm_init() which is run
after reserve_crashkernel(). Once kdump kernel is loaded, the
new arch_kexec_protect_crashkres() implemented for S390 will
actually unmap the pgtable like before.

> If you fix this comment, I am fine with your patch.
> Acked-by: Michael Holzheu <holzheu at linux.vnet.ibm.com>


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