resources: introduce generic page_is_ram()

It's based on walk_system_ram_range(), for archs that don't have
their own page_is_ram().

The static verions in MIPS and SCORE are also made global.

v4: prefer plain 1 instead of PAGE_IS_RAM (H. Peter Anvin)
v3: add comment (KAMEZAWA Hiroyuki)
    "AFAIK, this "System RAM" information has been used for kdump to
    grab valid memory area and seems good for the kernel itself."
v2: add PAGE_IS_RAM macro (Américo Wang)

Cc: Chen Liqin <liqin.chen@sunplusct.com>
Cc: Lennox Wu <lennox.wu@gmail.com>
Cc: Américo Wang <xiyou.wangcong@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: Yinghai Lu <yinghai@kernel.org>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
LKML-Reference: <20100122081619.GA6431@localhost>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index 83aa81297ea3..11ef7952b63a 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -188,5 +188,7 @@ extern int
 walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
                 void *arg, int (*func)(unsigned long, unsigned long, void *));
 
+extern int page_is_ram(unsigned long pfn);
+
 #endif /* __ASSEMBLY__ */
 #endif  /* _LINUX_IOPORT_H */