diff options
| -rw-r--r-- | arch/x86/Kconfig | 14 | ||||
| -rw-r--r-- | arch/x86/boot/header.S | 15 | ||||
| -rw-r--r-- | arch/x86/include/asm/efi.h | 11 | ||||
| -rw-r--r-- | arch/x86/kernel/setup.c | 2 | ||||
| -rw-r--r-- | arch/x86/platform/efi/efi.c | 2 |
5 files changed, 37 insertions, 7 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 0af5250d914f..8453fe1342ea 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1585,6 +1585,20 @@ config EFI_STUB See Documentation/efi-stub.txt for more information. +config EFI_MIXED + bool "EFI mixed-mode support" + depends on EFI_STUB && X86_64 + ---help--- + Enabling this feature allows a 64-bit kernel to be booted + on a 32-bit firmware, provided that your CPU supports 64-bit + mode. + + Note that it is not possible to boot a mixed-mode enabled + kernel via the EFI boot stub - a bootloader that supports + the EFI handover protocol must be used. + + If unsure, say N. + config SECCOMP def_bool y prompt "Enable seccomp to safely compute untrusted bytecode" diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S index d69d96653325..256388260c88 100644 --- a/arch/x86/boot/header.S +++ b/arch/x86/boot/header.S @@ -283,7 +283,7 @@ _start: # Part 2 of the header, from the old setup.S .ascii "HdrS" # header signature - .word 0x020c # header version number (>= 0x0105) + .word 0x020d # header version number (>= 0x0105) # or else old loadlin-1.5 will fail) .globl realmode_swtch realmode_swtch: .word 0, 0 # default_switch, SETUPSEG @@ -375,7 +375,8 @@ xloadflags: # define XLF0 0 #endif -#if defined(CONFIG_RELOCATABLE) && defined(CONFIG_X86_64) +#if defined(CONFIG_RELOCATABLE) && defined(CONFIG_X86_64) && \ + !defined(CONFIG_EFI_MIXED) /* kernel/boot_param/ramdisk could be loaded above 4g */ # define XLF1 XLF_CAN_BE_LOADED_ABOVE_4G #else @@ -383,10 +384,14 @@ xloadflags: #endif #ifdef CONFIG_EFI_STUB -# ifdef CONFIG_X86_64 -# define XLF23 XLF_EFI_HANDOVER_64 /* 64-bit EFI handover ok */ +# ifdef CONFIG_EFI_MIXED +# define XLF23 (XLF_EFI_HANDOVER_32|XLF_EFI_HANDOVER_64) # else -# define XLF23 XLF_EFI_HANDOVER_32 /* 32-bit EFI handover ok */ +# ifdef CONFIG_X86_64 +# define XLF23 XLF_EFI_HANDOVER_64 /* 64-bit EFI handover ok */ +# else +# define XLF23 XLF_EFI_HANDOVER_32 /* 32-bit EFI handover ok */ +# endif # endif #else # define XLF23 0 diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h index 85935e6f69f3..a3837254e320 100644 --- a/arch/x86/include/asm/efi.h +++ b/arch/x86/include/asm/efi.h @@ -152,6 +152,17 @@ static inline bool efi_is_native(void) return IS_ENABLED(CONFIG_X86_64) == efi_enabled(EFI_64BIT); } +static inline bool efi_runtime_supported(void) +{ + if (efi_is_native()) + return true; + + if (IS_ENABLED(CONFIG_EFI_MIXED) && !efi_enabled(EFI_OLD_MEMMAP)) + return true; + + return false; +} + extern struct console early_efi_console; extern void parse_efi_setup(u64 phys_addr, u32 data_len); diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index 06853e670354..ff9b3a62a05c 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -1243,7 +1243,7 @@ void __init setup_arch(char **cmdline_p) * mismatched firmware/kernel archtectures since there is no * support for runtime services. */ - if (efi_enabled(EFI_BOOT) && !efi_is_native()) { + if (efi_enabled(EFI_BOOT) && !efi_runtime_supported()) { pr_info("efi: Setup done, disabling due to 32/64-bit mismatch\n"); efi_unmap_memmap(); } diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c index 39f5b7bba695..395decedfa2b 100644 --- a/arch/x86/platform/efi/efi.c +++ b/arch/x86/platform/efi/efi.c @@ -802,7 +802,7 @@ void __init efi_init(void) * that doesn't match the kernel 32/64-bit mode. */ - if (!efi_is_native()) + if (!efi_runtime_supported()) pr_info("No EFI runtime due to 32/64-bit mismatch with kernel\n"); else { if (disable_runtime || efi_runtime_init()) |