From 4e5414b2a1fd84ac7b1b5c1e3e81de2412778b64 Mon Sep 17 00:00:00 2001 From: Daniel Kiper Date: Thu, 2 Feb 2017 15:19:18 +0100 Subject: [PATCH] i386/relocator: Align stack in grub_relocator64_efi relocator Unified Extensible Firmware Interface Specification, Version 2.6, section 2.3.4, x64 Platforms, boot services, says among others: The stack must be 16-byte aligned. So, do it. Otherwise OS may boot only by chance as it happens right now. Signed-off-by: Daniel Kiper --- grub-core/lib/i386/relocator64.S | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff --git a/grub-core/lib/i386/relocator64.S b/grub-core/lib/i386/relocator64.S index 75725cf75..148f38adb 100644 --- a/grub-core/lib/i386/relocator64.S +++ b/grub-core/lib/i386/relocator64.S @@ -73,14 +73,22 @@ VARIABLE(grub_relocator64_rsp) movq %rax, %rsp +#ifdef GRUB_MACHINE_EFI + jmp LOCAL(skip_efi_stack_align) + /* - * Here is grub_relocator64_efi_start() entry point. - * Following code is shared between grub_relocator64_efi_start() + * Here is grub_relocator64_efi_start() entry point. Most of the + * code below is shared between grub_relocator64_efi_start() * and grub_relocator64_start(). * - * Think twice before changing anything below!!! + * Think twice before changing anything there!!! */ VARIABLE(grub_relocator64_efi_start) + /* Align the stack as UEFI spec requires. */ + andq $~15, %rsp + +LOCAL(skip_efi_stack_align): +#endif /* mov imm64, %rax */ .byte 0x48 .byte 0xb8 @@ -128,8 +136,10 @@ LOCAL(jump_addr): VARIABLE(grub_relocator64_rip) .quad 0 +#ifdef GRUB_MACHINE_EFI /* Here grub_relocator64_efi_start() ends. Ufff... */ VARIABLE(grub_relocator64_efi_end) +#endif #ifndef __x86_64__ .p2align 4