[PATCH] arch : arm : add a criteria for pfn_valid

[Zhaoyang Huang]

From: Zhaoyang Huang <zhaoyang.huang@xxxxxxxxxx>

pfn_valid can be wrong while the MSB of physical address be trimed as pfn
larger than the max_pfn.

Signed-off-by: Zhaoyang Huang <huangzhaoyang@xxxxxxxxx>
---
 arch/arm/mm/init.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index c2daabb..9c4d938 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -177,7 +177,8 @@ static void __init zone_sizes_init(unsigned long min, unsigned long max_low,
 #ifdef CONFIG_HAVE_ARCH_PFN_VALID
 int pfn_valid(unsigned long pfn)
 {
-	return memblock_is_map_memory(__pfn_to_phys(pfn));
+	return (pfn > max_pfn) ?
+		false : memblock_is_map_memory(__pfn_to_phys(pfn));
 }
 EXPORT_SYMBOL(pfn_valid);
 #endif
-- 
1.9.1