Re: [gentoo-dev] Re: Killing UEFI Secure Boot

[Richard Yao]

On 06/22/2012 01:10 AM, Richard Yao wrote:
> On 06/22/2012 01:02 AM, Duncan wrote:
>> Richard Yao posted on Thu, 21 Jun 2012 05:33:22 -0400 as excerpted:
>>
>>> A firmware replacement for the BIOS does not need to worry about floppy
>>> drives, hard drives, optical drives, usb devices, isa devices, pci
>>> devices and pci express drives, etcetera, because those live on buses,
>>> which the kernel can detect.
>> But you have to be able to load the kernel first, before it can do all
>> that detection.  And to load it, you need to be able to read the device
>> it's located on, which in a modern x86 system (as contrasted with mips/
>> arm) generally means detection of what's there, some mechanism to choose
>> which available devices to check for a kernel or boot loader or whatever,
>> and some way to dynamically configure it, since many devices are simply
>> (device info probable) bricks until configured, these days.
>>
>> Sure, you can boot directly to a Linux kernel /as/ your firmware (as Ian
>> S suggested), but then you're back to hard-configuring it in ordered to
>> do so, thus losing all that extra flexibility that's part of what makes
>> x86 different.  Which was the question that I was addressing.
>>
> Placing it in the firmware is what I suggested. I also later stated that
> it is possible for the firmware to contain an initramfs that would
> enable it to start a kernel located on a device.
>
> It seems to me that this would work if device trees for motherboards
> were readily available and the EEPROM chips have sufficient capacity. I
> am under the impression that UEFI firmware is large enough that capacity
> on UEFI motherboards should not be an issue. The main issue would be
> obtaining device trees.
>
Before anyone says it, information on how to initialize the memory
controller and possibly a few other bits prior to loading the kernel is
also necessary. I omitted that by mistake.