diff --git a/ChangeLog b/ChangeLog
index ca8ea2e5d..38a97db5b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2013-11-19  Josh Triplett  <josh@joshtriplett.org>
+
+	* grub-core/kern/x86_64/efi/startup.S (_start): Align the stack to a
+	16-byte boundary, as required by the x86-64 ABI, before calling
+	grub_main.  In some cases, GCC emits code that assumes this
+	alignment, which crashes if not aligned.  The EFI firmware is also
+	entitled to assume that stack alignment without checking.
+
 2013-11-18  Josh Triplett  <josh@joshtriplett.org>
 
 	* grub-core/mmap/efi/mmap.c (grub_mmap_register): Round up/down to
diff --git a/grub-core/kern/x86_64/efi/startup.S b/grub-core/kern/x86_64/efi/startup.S
index f86f01969..9357e5c5d 100644
--- a/grub-core/kern/x86_64/efi/startup.S
+++ b/grub-core/kern/x86_64/efi/startup.S
@@ -30,6 +30,6 @@ _start:
 	movq	%rcx, EXT_C(grub_efi_image_handle)(%rip)
 	movq	%rdx, EXT_C(grub_efi_system_table)(%rip)
 
+	andq	$~0xf, %rsp
 	call	EXT_C(grub_main)
-	ret
-
+	/* Doesn't return.  */