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/efi.c b/arch/x86/kernel/efi.c
index 94382fa..06cc8d4 100644
--- a/arch/x86/kernel/efi.c
+++ b/arch/x86/kernel/efi.c
@@ -473,7 +473,7 @@
size = md->num_pages << EFI_PAGE_SHIFT;
end = md->phys_addr + size;
- if (PFN_UP(end) <= max_pfn_mapped)
+ if (PFN_UP(end) <= max_low_pfn_mapped)
va = __va(md->phys_addr);
else
va = efi_ioremap(md->phys_addr, size);