fs/proc/kcore.c:144: error: 'max_low_pfn' undeclared (first use in this function)
fs/proc/kcore.c:144: error: (Each undeclared identifier is reported only once
fs/proc/kcore.c:144: error: for each function it appears in.)

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>