diff options
| author | Matt Fleming <matt.fleming@intel.com> | 2012-07-19 10:23:48 +0100 |
|---|---|---|
| committer | H. Peter Anvin <hpa@zytor.com> | 2012-07-20 16:18:58 -0700 |
| commit | 9ca8f72a9297f2052d806bd1111e176533aa69bd (patch) | |
| tree | 520e3a306588bd49ae618a7e1930028e4e38ea01 /arch/x86/boot/header.S | |
| parent | bacef661acdb634170a8faddbc1cf28e8f8b9eee (diff) | |
x86, efi: Handover Protocol
As things currently stand, traditional EFI boot loaders and the EFI
boot stub are carrying essentially the same initialisation code
required to setup an EFI machine for booting a kernel. There's really
no need to have this code in two places and the hope is that, with
this new protocol, initialisation and booting of the kernel can be
left solely to the kernel's EFI boot stub. The responsibilities of the
boot loader then become,
o Loading the kernel image from boot media
File system code still needs to be carried by boot loaders for the
scenario where the kernel and initrd files reside on a file system
that the EFI firmware doesn't natively understand, such as ext4, etc.
o Providing a user interface
Boot loaders still need to display any menus/interfaces, for example
to allow the user to select from a list of kernels.
Bump the boot protocol number because we added the 'handover_offset'
field to indicate the location of the handover protocol entry point.
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Peter Jones <pjones@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Acked-and-Tested-by: Matthew Garrett <mjg@redhat.com>
Link: http://lkml.kernel.org/r/1342689828-16815-1-git-send-email-matt@console-pimps.org
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'arch/x86/boot/header.S')
| -rw-r--r-- | arch/x86/boot/header.S | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S index 8bbea6aa40d9..097f4760faea 100644 --- a/arch/x86/boot/header.S +++ b/arch/x86/boot/header.S @@ -263,7 +263,7 @@ _start: # Part 2 of the header, from the old setup.S .ascii "HdrS" # header signature - .word 0x020a # header version number (>= 0x0105) + .word 0x020b # header version number (>= 0x0105) # or else old loadlin-1.5 will fail) .globl realmode_swtch realmode_swtch: .word 0, 0 # default_switch, SETUPSEG @@ -381,6 +381,8 @@ pref_address: .quad LOAD_PHYSICAL_ADDR # preferred load addr #define INIT_SIZE VO_INIT_SIZE #endif init_size: .long INIT_SIZE # kernel initialization size +handover_offset: .long 0x30 # offset to the handover + # protocol entry point # End of setup header ##################################################### |