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authorWu Fengguang <fengguang.wu@intel.com>2010-01-22 16:16:19 +0800
committerH. Peter Anvin <hpa@zytor.com>2010-02-01 16:58:17 -0800
commit61ef2489dbf587258526cfd4ebf4bba3b079f401 (patch)
tree4806ed052c73d84821d958f306699b2a27da965e /kernel/resource.c
parentccef086454d4c97e7b722e9303390207d681cb4c (diff)
downloadlwn-61ef2489dbf587258526cfd4ebf4bba3b079f401.tar.gz
lwn-61ef2489dbf587258526cfd4ebf4bba3b079f401.zip
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>
Diffstat (limited to 'kernel/resource.c')
-rw-r--r--kernel/resource.c13
1 files changed, 13 insertions, 0 deletions
diff --git a/kernel/resource.c b/kernel/resource.c
index fb11a58b9594..b4d637a55256 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -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.
*/