[PATCH] x86: fix EFI memory map parsing

The memory descriptors that comprise the EFI memory map are not fixed in
stone such that the size could change in the future.  This uses the memory
descriptor size obtained from EFI to iterate over the memory map entries
during boot.  This enables the removal of an x86 specific pad (and ifdef)
in the EFI header.  I also couldn't stomach the broken up nature of the
function to put EFI runtime calls into virtual mode any longer so I fixed
that up a bit as well.

For reference, this patch only impacts x86.

Signed-off-by: Matt Tolentino <matthew.e.tolentino@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 9 insertions, 5 deletions

diff --git a/arch/i386/kernel/setup.c b/arch/i386/kernel/setup.c
index af4de58cab54..9adbf710ec8d 100644
--- a/arch/i386/kernel/setup.c
+++ b/arch/i386/kernel/setup.c
@@ -370,12 +370,16 @@ static void __init limit_regions(unsigned long long size)
         int i;
 
         if (efi_enabled) {
-                for (i = 0; i < memmap.nr_map; i++) {
-                        current_addr = memmap.map[i].phys_addr +
-                                       (memmap.map[i].num_pages << 12);
-                        if (memmap.map[i].type == EFI_CONVENTIONAL_MEMORY) {
+                efi_memory_desc_t *md;
+                void *p;
+
+                for (p = memmap.map, i = 0; p < memmap.map_end;
+                        p += memmap.desc_size, i++) {
+                        md = p;
+                        current_addr = md->phys_addr + (md->num_pages << 12);
+                        if (md->type == EFI_CONVENTIONAL_MEMORY) {
                                 if (current_addr >= size) {
-                                        memmap.map[i].num_pages -=
+                                        md->num_pages -=
                                                 (((current_addr-size) + PAGE_SIZE-1) >> PAGE_SHIFT);
                                         memmap.nr_map = i + 1;
                                         return;