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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>
This commit is contained in:
Wu Fengguang 2010-01-22 16:16:19 +08:00 committed by H. Peter Anvin
parent ccef086454
commit 61ef2489db
4 changed files with 17 additions and 2 deletions

View File

@ -294,7 +294,7 @@ void __init fixrange_init(unsigned long start, unsigned long end,
}
#ifndef CONFIG_NEED_MULTIPLE_NODES
static int __init page_is_ram(unsigned long pagenr)
int page_is_ram(unsigned long pagenr)
{
int i;

View File

@ -59,7 +59,7 @@ static unsigned long setup_zero_page(void)
}
#ifndef CONFIG_NEED_MULTIPLE_NODES
static int __init page_is_ram(unsigned long pagenr)
int page_is_ram(unsigned long pagenr)
{
if (pagenr >= min_low_pfn && pagenr < max_low_pfn)
return 1;

View File

@ -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 */

View File

@ -297,6 +297,19 @@ int walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
#endif
static int __is_ram(unsigned long pfn, unsigned long nr_pages, void *arg)
{
return 1;
}
/*
* This generic page_is_ram() returns true if specified address is
* registered as "System RAM" in iomem_resource list.
*/
int __attribute__((weak)) page_is_ram(unsigned long pfn)
{
return walk_system_ram_range(pfn, 1, NULL, __is_ram) == 1;
}
/*
* Find empty slot in the resource tree given range and alignment.
*/