[U-Boot] [PATCH 1/1] distro_bootcmd: Switch bootefi to use loadaddr by default.

[Alexander Graf]

On 07.08.18 09:26, Kristian Amlie wrote:
> On 07/08/18 00:06, Alexander Graf wrote:
>> On 06.08.18 13:00, Kristian Amlie wrote:
>>> Ping. Any objections to this change?
>>
>> I definitely don't want to have the bootefi path behave any different
>> from the other distro boot targets. That would just cause confusion down
>> the road.
>>
>> Do they (pxe boot, extlinux, etc) make use of loadaddr?
> 
> No, you're right, apparently they use kernel_addr_r AFAICS [1].
> 
> So maybe it is better to stay with kernel_addr_r. The problem is that
> not all boards follow this, and there are various "bootm ${loadaddr}"
> and "bootz ${loadaddr}" sprinkled across the various board headers,
> indicating that they use this.

Yes, they haven't been converted to distro boot then :). So the path
forward for those would be to convert them and slowly deprecate loadaddr.

> What I want out of this exercise is to make sure that the EFI path in
> distro_bootcmd will be able to boot an EFI app on any board, regardless
> of whether it uses kernel_addr_r or loadaddr. Sounds reasonable, right?

If you enable distro boot for a board, one of the requirement is that
kernel_addr_r is set to a reasonable value:


http://git.denx.de/?p=u-boot.git;a=blob;f=doc/README.distro;h=f8e9752a0fa4244ef0a6f7ee530b0aa218080cac;hb=HEAD#l236

> Following that it seems natural to standardize on one of the two, but it
> is not entirely clear from the source code which one it should be. I
> picked loadaddr because it has a CONFIG_LOADADDR define, unlike
> kernel_addr_r which is just hardcoded in a lot of places, and thus
> seemed less "proper". But I'm fine with staying with kernel_addr_r as well.

I think kernel_addr_r is the defined one for distro boot, yes.

> 
> There are several things I could do from here on:
> 
> 
> 1. Keep the current patch, but add "loadaddr" to pxe and extlinux
> variants as well to get consistent behavior.
> 
> 2. Reverse order of attempts, and try to use kernel_addr_r first, then
> loadaddr. Possibly this could also include a patch to pxe and extlinux
> to make them behave the same.
> 
> 3. Do nothing, and keep kernel_addr_r as the one and only. IMHO this
> implicitly means that loadaddr should be deprecated and removed, given
> their overlapping meaning, and boards converted to using kernel_addr_r.

I think this is the best option. Just convert boards you care about
slowly over to distro boot (which implicitly means they also use
kernel_addr_r). For other boards you can not rely on any EFI boot path
enumeration anyway, because the boot command doesn't search for EFI
binaries ;).


Thanks,

Alex

> 
> 4. Opposite of 3, make loadaddr into the one and only, and convert all
> boards to that.
> 
> 
> Personally I think either option 1 or option 2 is the best, both quite
> smooth transition paths. Option 3 or 4 are perhaps cleaner solutions in
> the long term, but are *a lot* more work, and much more likely to cause
> breakage as well.
> 
> What do you think?
> 
> 
> [1]
> http://git.denx.de/?p=u-boot.git;a=blob;f=cmd/pxe.c;h=5609545de575d090b27f48fd0d2d2ee61b8bdc73;hb=HEAD#l701
>