x86: introduce max_low_pfn_mapped for 64-bit
when more than 4g memory is installed, don't map the big hole below 4g.
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index a31a579..9c981c4 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -130,7 +130,7 @@
if (!phys || !size)
return NULL;
- if (phys+size <= (max_pfn_mapped << PAGE_SHIFT))
+ if (phys+size <= (max_low_pfn_mapped << PAGE_SHIFT))
return __va(phys);
offset = phys & (PAGE_SIZE - 1);