x86/efi/32: Fix EFI on systems where the per-cpu GDT is virtually mapped

__pa() on a per-cpu pointer is invalid.  This bug appears to go *waaay*
back, and I guess it's just never been triggered.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Garnier <thgarnie@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/5ba1d3ffca85e1a5b3ac99265ebe55df4cf0dbe4.1490218061.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/platform/efi/efi_32.c b/arch/x86/platform/efi/efi_32.c
index 9500711..3481268 100644 (file)
--- a/arch/x86/platform/efi/efi_32.c
+++ b/arch/x86/platform/efi/efi_32.c
@@ -68,7 +68,7 @@ pgd_t * __init efi_call_phys_prolog(void)
        load_cr3(initial_page_table);
        __flush_tlb_all();
 
-       gdt_descr.address = __pa(get_cpu_gdt_rw(0));
+       gdt_descr.address = get_cpu_gdt_paddr(0);
        gdt_descr.size = GDT_SIZE - 1;
        load_gdt(&gdt_descr);