[arch-releng] [DRAFT][RFC][PATCH][archiso] Add UEFI boot support via Linux >= 3.3 EFI boot stub.

Gerardo Exequiel Pozzi vmlinuz386 at yahoo.com.ar
Tue Mar 27 09:26:05 EDT 2012

On 03/27/2012 02:31 AM, Keshav P R wrote:
> On Tue, Mar 27, 2012 at 07:04, Gerardo Exequiel Pozzi
> <vmlinuz386 at yahoo.com.ar>  wrote:
>> On 03/26/2012 11:16 AM, Keshav P R wrote:
>>> On Tue, Mar 20, 2012 at 23:15, Gerardo Exequiel Pozzi
>>> <vmlinuz386 at yahoo.com.ar>    wrote:
>>>>> This is going to increase the iso size like hell. Having the kernel
>>>>> and initrd files within a FAT image inside the iso is not a good idea.
>>>>> A 32 MB fat image, come on. I know this is required for CD booting,
>>>>> but this is not a good idea with efistub efilinux or elilo etc. For
>>>>> USB booting you can just have the files in the iso itself, wherein the
>>>>> user simply extract the iso in a FAT32 USB and boots from it. I say
>>>>> drop support for iso booting via this fat fs image and support uefi
>>>>> boot only in case of USBs.
>>>>>
>>>>> Regards.
>>>>>
>>>>> Keshav
>>>>>
>>>> OK, so just ignore this draft patch. UEFI boot support can be made
>>>> manually by the user, just doing a copy of vmlinuz to the right place and
>>>> optionally installing a boot manager.
>>>>
>>>> A documentation on the wiki is sufficient.
>>> You might be interested in rEFInd-x86_64
>>> https://aur.archlinux.org/packages.php?ID=57632 which provides a nice
>>>
>>> Related info :
>>> http://www.rodsbooks.com/refind/linux.html
>>>
>>> [QUOTE from http://www.rodsbooks.com/refind/linux.html]
>>> rEFInd looks for a file called linux.conf in the same directory as the
>>> kernel file. This file is a practical requirement for booting from an
>>> auto-detected kernel. It consists of a series of lines, each of which
>>> consists of a label followed by a series of kernel options. The first
>>> line sets default options, and subsequent lines set options that are
>>>
>>> The intent of this system is that distribution maintainers can place
>>> their kernels, initial RAM disks, and a linux.conf file in their own
>>> subdirectory on the ESP. rEFInd will detect their kernels and create
>>> one main menu entry for each kernel. Each entry will implement as many
>>> options as there are lines in the linux.conf file. In this way, two or
>>> more distributions can each maintain their boot loader entries,
>>> without being too concerned for who maintains rEFInd as a whole.
>>> [/QUOTE]
>>>
>>> The filename has been changed to refind_linux.conf in the upstream git
>>> repo so that it does not conflict with the proposed efistub config
>>> file by kernel devs
>>>
>>>
>>> This should be pretty straightforward to implement in Archiso. For
>>> non-EFISTUB kernels like LTS ones, you can use efilinux-x86_64
>>> https://aur.archlinux.org/packages.php?ID=57972 (Usage instructions -
>>> http://article.gmane.org/gmane.linux.kernel/1175060). This might be a
>>> good alternative for grub2 uefi boot, although booting i686 kernels in
>>> x86_64 UEFI will not be supported by EFISTUB (which can be done using
>>> grub2). Support for mixed arch booting seems to have been merged for
>>> 3.4-rc1 .
>>>
>>> Regards.
>>>
>>> Keshav
>>>
>> Thanks for the work.
>>
>> But this only added the advantage of passing command line options to the
>> kernel. We still need a "FAT image" with bootx64.efi (rEFInd) + vmlinuz.efi
>> + archiso.img (initramfs) + refind*.conf (for El Torito) that was the main
>> dissapointed issue. Otherwise rEFInd can not find what file to load.
>>
> No. In this case just rEFInd (and the required icons -  not all of
> them) needs to be in the FAT image. The kernels and initramfs can be
> in (ISO)/efi/(SUBDIR)/ along with (ISO)/efi/(SUBDIR)/refind_linux.conf
> containing the kernel parameters. If the (SUBDIR) is "arch" , ie.
> (ISO)/efi/arch/ , then refind will even display Archlinux icon making
> it easy for the user to differentiate the iso kernels from other
> kernels.
>
> All the answers are at http://www.rodsbooks.com/refind/ .
>
> Regards.
>
> Keshav
>
Are you sure?

The only thing that can do rEFInd is launch EFI apps from drives listed
by EFI firmware. A filesystem ISO9660 is not listed as a drive with
filesystem by EFI, and rEFInd does not understand about ISO9660.

Thanks.

--
Gerardo Exequiel Pozzi
\cos^2\alpha + \sin^2\alpha = 1