[systemd-devel] [systemd-commits] 3 commits - .gitignore Makefile.am src/bootchart src/core src/efi-boot-generator src/shared

[Kay Sievers]

On Mon, Jan 21, 2013 at 12:49 PM, Colin Guthrie <gmane at colin.guthr.ie> wrote:
> 'Twas brillig, and Kay Sievers at 21/01/13 11:03 did gyre and gimble:
>> On Mon, Jan 21, 2013 at 7:29 AM, Andrey Borzenkov <arvidjaar at gmail.com> wrote:
>>
>>>> commit f4ce2b3e5ce93b83f14f8785e205ebb5a9b8c1df
>>>> Author: Lennart Poettering <lennart at poettering.net>
>>>> Date:   Mon Jan 21 01:02:53 2013 +0100
>>>>
>>>>     efi: add efi boot generator that automatically mounts the ESP to /boot
>>>
>>> Has something changed? ESP has always been mounted on /boot/efi, and
>>> mounting it on /boot is plain wrong; ESP is shared resource for all OS
>>> installed, not private space to place files of this specific
>>> installation.
>>
>> The Linux kernel acts as an EFI boot loader, if copied to the ESP it
>> can be directly executed by the EFI firmware.
>>
>> The initramfs and the kernel live in a vendor sub-directory in the ESP
>> and are read directly by EFI code, and there is no need for grub2, any
>> other additional filesystem driver, raid, network setup, or whatever
>> additional code people think they would need to bring up all sorts of
>> systems.
>>
>> The kernel itself with the initramfs can boot everything, has all the
>> filesystem access which is ever needed, there is no need for anything
>> else on EFI machines. Even the craziest setups can boot directly out
>> of the firmware that way.
>>
>> It's the simplest and most efficient setup a system can have.
>>
>> And "plain wrong" is the sick game which is called grub2, not mounting
>> the EFI partition at /boot. :)
>
> Forgive the noob question (as I have no EFI h/w to be bothered to learn
> this stuff!), but if What Andrey says is correct would this mean we
> cannot have two separate installs without sharing the same /boot?

Sure, why not? You just have to make sure, that the files you copy to
/boot are in properly named subdirectories. /boot is meant to be
"owned" by the machine, not by the installed distribution, so the
distribution has to behave in /boot and not do what they usually do
with RPM today.

The kernel+initramfs acts as the boot loader here, which can boot from
everything and can read every hardware, every sotrage setup, that's
all; nothing else is needed on /boot in a "non-bullshit" setup. Did I
mention grub2 already? :)

> (or even a Windows install assuming it uses that space too?). Can you
> comment on those kind of set ups?

Should all work fine. The EFI partition with the vendor
sub-directories is by-design intended to be shared by multiple
installations.

Anyway, this is all just what we personally use, what we want to have
supported by default. It will not get active for any other setup
because of the conditions in the generator.

It's not any distributions default, it's just the simplest and most
efficient setup an EFI boot can have.