On some EFI systems (i.e. Apple) EFI runtime is mapped into higher mem regions. These EFI mem regions are not always taken into consideration when max_pfn is calculated in setup.c being that e820_end_of_ram_pfn() only counts mappings types marked as usable (E820_RAM). Currently we only count to the last usable e820 address range and nothing beyond. EFI can be mapped anywhere within e820 and is not always marked as usable e820, and so EFI runtime may be missed if mapped somewhere beyond last usable e820. This patch attempts to resolve this problem by including all E820 mappings when EFI is enabled, so that the entire e820 (and EFI runtime area) is included in computing max_pfn. Tested on a MacBook Pro 3.1 and resolves the issue (system now boots w/elilo+grub & EFI). Signed-off-by: Brian Maly e820.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-)