x86: EFI: fix use of unitialized variable and the cache logic

Andi Kleen pointed out that the cache attribute logic is reverse in
efi_enter_virtual_mode(). This problem alone is harmless as we do not
(yet) do cache attribute conflict resolution. (This bug was not present
in the original EFI submission - I introduced it while fixing up rejects.)

While reviewing this code I noticed a second, worse problem: the use of
uninitialized md->virt_addr.

Fix both problems.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 3 insertions, 3 deletions

diff --git a/arch/x86/kernel/efi.c b/arch/x86/kernel/efi.c
index 32dd62b36ff7..b4d523276f40 100644
--- a/arch/x86/kernel/efi.c
+++ b/arch/x86/kernel/efi.c
@@ -428,9 +428,6 @@ void __init efi_enter_virtual_mode(void)
                 else
                         va = efi_ioremap(md->phys_addr, size);
 
-                if (md->attribute & EFI_MEMORY_WB)
-                        set_memory_uc(md->virt_addr, size);
-
                 md->virt_addr = (u64) (unsigned long) va;
 
                 if (!va) {
@@ -439,6 +436,9 @@ void __init efi_enter_virtual_mode(void)
                         continue;
                 }
 
+                if (!(md->attribute & EFI_MEMORY_WB))
+                        set_memory_uc(md->virt_addr, size);
+
                 systab = (u64) (unsigned long) efi_phys.systab;
                 if (md->phys_addr <= systab && systab < end) {
                         systab += md->virt_addr - md->phys_addr;