diff options
| -rw-r--r-- | arch/x86/Kconfig | 17 | ||||
| -rw-r--r-- | arch/x86/boot/compressed/head_64.S | 4 | ||||
| -rw-r--r-- | arch/x86/boot/header.S | 2 | ||||
| -rw-r--r-- | arch/x86/boot/tools/build.c | 2 |
4 files changed, 23 insertions, 2 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 67745ceab0db..a0fb8363fe63 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1980,6 +1980,23 @@ config EFI_STUB See Documentation/admin-guide/efi-stub.rst for more information. +config EFI_HANDOVER_PROTOCOL + bool "EFI handover protocol (DEPRECATED)" + depends on EFI_STUB + default y + help + Select this in order to include support for the deprecated EFI + handover protocol, which defines alternative entry points into the + EFI stub. This is a practice that has no basis in the UEFI + specification, and requires a priori knowledge on the part of the + bootloader about Linux/x86 specific ways of passing the command line + and initrd, and where in memory those assets may be loaded. + + If in doubt, say Y. Even though the corresponding support is not + present in upstream GRUB or other bootloaders, most distros build + GRUB with numerous downstream patches applied, and may rely on the + handover protocol as as result. + config EFI_MIXED bool "EFI mixed-mode support" depends on EFI_STUB && X86_64 diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index 6ba2c2142c33..d4c4281db635 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -286,7 +286,7 @@ SYM_FUNC_START(startup_32) lret SYM_FUNC_END(startup_32) -#ifdef CONFIG_EFI_MIXED +#if IS_ENABLED(CONFIG_EFI_MIXED) && IS_ENABLED(CONFIG_EFI_HANDOVER_PROTOCOL) .org 0x190 SYM_FUNC_START(efi32_stub_entry) add $0x4, %esp /* Discard return address */ @@ -516,7 +516,9 @@ trampoline_return: SYM_CODE_END(startup_64) #ifdef CONFIG_EFI_STUB +#ifdef CONFIG_EFI_HANDOVER_PROTOCOL .org 0x390 +#endif SYM_FUNC_START(efi64_stub_entry) and $~0xf, %rsp /* realign the stack */ movq %rdx, %rbx /* save boot_params pointer */ diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S index f912d7770130..d31982509654 100644 --- a/arch/x86/boot/header.S +++ b/arch/x86/boot/header.S @@ -406,7 +406,7 @@ xloadflags: # define XLF1 0 #endif -#ifdef CONFIG_EFI_STUB +#ifdef CONFIG_EFI_HANDOVER_PROTOCOL # ifdef CONFIG_EFI_MIXED # define XLF23 (XLF_EFI_HANDOVER_32|XLF_EFI_HANDOVER_64) # else diff --git a/arch/x86/boot/tools/build.c b/arch/x86/boot/tools/build.c index a3725ad46c5a..bd247692b701 100644 --- a/arch/x86/boot/tools/build.c +++ b/arch/x86/boot/tools/build.c @@ -290,6 +290,7 @@ static void efi_stub_entry_update(void) { unsigned long addr = efi32_stub_entry; +#ifdef CONFIG_EFI_HANDOVER_PROTOCOL #ifdef CONFIG_X86_64 /* Yes, this is really how we defined it :( */ addr = efi64_stub_entry - 0x200; @@ -299,6 +300,7 @@ static void efi_stub_entry_update(void) if (efi32_stub_entry != addr) die("32-bit and 64-bit EFI entry points do not match\n"); #endif +#endif put_unaligned_le32(addr, &buf[0x264]); } |