tree 0f10dac15f4c2266d7d49f02ae4920863497dc32
parent d38593f9387055566b782d00d38d9a347a96e7d9
author Michael Holzheu <holzheu@linux.vnet.ibm.com> 1319984203 +0100
committer Martin Schwidefsky <schwidefsky@de.ibm.com> 1319984202 +0100

[S390] kdump: Add infrastructure for unmapping crashkernel memory

This patch introduces a mechanism that allows architecture backends to
remove page tables for the crashkernel memory. This can protect the loaded
kdump kernel from being overwritten by broken kernel code.  Two new
functions crash_map_reserved_pages() and crash_unmap_reserved_pages() are
added that can be implemented by architecture code.  The
crash_map_reserved_pages() function is called before and
crash_unmap_reserved_pages() after the crashkernel segments are loaded.  The
functions are also called in crash_shrink_memory() to create/remove page
tables when the crashkernel memory size is reduced.

To support architectures that have large pages this patch also introduces
a new define KEXEC_CRASH_MEM_ALIGN. The crashkernel start and size must
always be aligned with KEXEC_CRASH_MEM_ALIGN.

Cc: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>