Hi Ilias, On Wed, 2 Aug 2023 at 07:02, Ilias Apalodimas <ilias.apalodi...@linaro.org> wrote: > > Hi Simon, > > On Wed, 2 Aug 2023 at 15:52, Simon Glass <s...@chromium.org> wrote: > > > > Hi Ilias, > > > > On Wed, 2 Aug 2023 at 00:52, Ilias Apalodimas > > <ilias.apalodi...@linaro.org> wrote: > > > > > > On Tue, 1 Aug 2023 at 19:19, Tom Rini <tr...@konsulko.com> wrote: > > > > > > > > On Tue, Aug 01, 2023 at 05:10:08PM +0100, Abdellatif El Khlifi wrote: > > > > > Hi guys, > > > > > > > > > > On Tue, Aug 01, 2023 at 11:00:57AM -0400, Tom Rini wrote: > > > > > > > > > > > > > ... > > > > > > > > > > > > > Changelog: > > > > > > > > > > > > > =============== > > > > > > > > > > > > > > > > > > > > > > > > > > v17: > > > > > > > > > > > > > > > > > > > > > > > > > > * show a debug message rather than an error when FF-A > > > > > > > > > > > > > is not detected > > > > > > > > > > > > [snip] > > > > > > > > > > > > > diff --git a/lib/efi_loader/Kconfig > > > > > > > > > > > > > b/lib/efi_loader/Kconfig > > > > > > > > > > > > > index c5835e6ef6..8fbadb9201 100644 > > > > > > > > > > > > > --- a/lib/efi_loader/Kconfig > > > > > > > > > > > > > +++ b/lib/efi_loader/Kconfig > > > > > > > > > > > > > @@ -55,13 +55,53 @@ config EFI_VARIABLE_FILE_STORE > > > > > > > > > > > > > stored as file /ubootefi.var on the EFI > > > > > > > > > > > > > system partition. > > > > > > > > > > > > > > > > > > > > > > > > > > config EFI_MM_COMM_TEE > > > > > > > > > > > > > - bool "UEFI variables storage service via OP-TEE" > > > > > > > > > > > > > - depends on OPTEE > > > > > > > > > > > > > + bool "UEFI variables storage service via the > > > > > > > > > > > > > trusted world" > > > > > > > > > > > > > + depends on OPTEE && ARM_FFA_TRANSPORT > > > > > > > > > > > > > > > > > > > > > > > > You didn't get my changes in here however. If you can > > > > > > > > > > > > do EFI_MM_COMM_TEE > > > > > > > > > > > > without ARM_FFA_TRANSPORT (as > > > > > > > > > > > > lx2160ardb_tfa_stmm_defconfig does) then > > > > > > > > > > > > you don't make this option depend on . If FF-A is only > > > > > > > > > > > > for use here, you make FF-A depend on this, and the > > > > > > > > > > > > FF-A specific > > > > > > > > > > > > variable depend on ARM_FFA_TRANSPORT. > > > > > > > > > > > > > > > > > > > > > > Abdellatif hinted at what's going on here. When I added > > > > > > > > > > > this Kconfig > > > > > > > > > > > option to lx2160 FF-A wasn't implemented yet. > > > > > > > > > > > > > > > > > > > > The defconfig has existed since May 2020, which is when you > > > > > > > > > > added > > > > > > > > > > EFI_MM_COMM_TEE itself too. So I think it's that no one > > > > > > > > > > did the check I > > > > > > > > > > did until now and saw this series was disabling what was on > > > > > > > > > > the other > > > > > > > > > > platform. > > > > > > > > > > > > > > > > > > > > > Since FF-A isn't a new > > > > > > > > > > > communication mechanism but builds upon the existing SMCs > > > > > > > > > > > to build an > > > > > > > > > > > easier API, I asked Abdellatif to hide this complexity. > > > > > > > > > > > We had two options, either make Kconfig options for > > > > > > > > > > > either FF-A or the > > > > > > > > > > > traditional SMCs and remove the dependencies, or > > > > > > > > > > > piggyback on FF-As > > > > > > > > > > > discovery mechanism and make the choice at runtime. The > > > > > > > > > > > latter has a > > > > > > > > > > > small impact on code size, but imho makes developers' > > > > > > > > > > > life a lot > > > > > > > > > > > easier. > > > > > > > > > > > > > > > > > > > > I'm not sure how much you can do a run-time option here > > > > > > > > > > since you're > > > > > > > > > > setting a bunch of default values for FF-A to 0 in Kconfig. > > > > > > > > > > If we're > > > > > > > > > > supposed to be able to get them at run time, we shouldn't > > > > > > > > > > need a Kconfig > > > > > > > > > > option at all. I'm also not sure how valid a use case it > > > > > > > > > > is where we > > > > > > > > > > won't know at build time what the rest of the firmware > > > > > > > > > > stack supports > > > > > > > > > > here. > > > > > > > > > > > > > > > > > > > > > > > > > > > > That's a fair point. FF-A in theory has APIs to discover > > > > > > > > > memory. > > > > > > > > > Abdellatif, why do we need the Kconfigs for shared memory on > > > > > > > > > FF-A? > > > > > > > > > > > > > > > > The statically carved out MM shared buffer address, size and > > > > > > > > offset cannot be discovered by FF-A ABIs. > > > > > > > > The MM communication driver in U-Boot could allocate the buffer > > > > > > > > and share it with the MM SP but > > > > > > > > we do not implement that support currently in either U-Boot or > > > > > > > > UEFI. > > > > > > > > > > > > > > Ok, that's a bit unfortunate, but Tom is right. Having the FF-A > > > > > > > addresses show up is as confusing as having Kconfig options for > > > > > > > discrete options. The whole point of my suggestion was to make > > > > > > > users' > > > > > > > lives easier. Apologies for the confusion but can you bring back > > > > > > > the > > > > > > > ifdefs? Looking at the patch this should be minimal just use > > > > > > > ifdef ARM_FFA_TRANSPORT and ifndef ARM_FFA_TRANSPORT. > > > > > > > > > > > > > > Tom you prefer that as well? > > > > > > > > > > > > Pending an answer to Jens' feedback, yes, going back to #ifdef's is > > > > > > fine, especially since default values of 0 are nonsense in this case > > > > > > (and as Heinrich's patch re SYS_MALLOC_LEN shows, dangerous since 0 > > > > > > != > > > > > > 0x0 once we do string comparisons). > > > > > > > > > > > > > > > > I'd like to give some context why it's important for Corstone-1000 > > > > > platform > > > > > that the DT passed to the kernel matches the official kernel DT. > > > > > > > > Note that we've set aside the "should this be in DT or not" question. > > > > > > > > > There is a SystemReady IR 2.0 test checking the DT. It compares the DT > > > > > passed by U-Boot with a reference DT (the kernel DT) . The test fails > > > > > if there > > > > > is a mismatch. So, if we add a DT node in U-Boot and the node is not > > > > > upstreamed > > > > > to the kernel DT, the DT test will fail. > > > > > > > > This is overall good and progress. > > > > > > > > > To be approved by the kernel DT maintainers, the node should have a > > > > > use case > > > > > in the kernel which is not the case. > > > > > > > > This is, I believe / hope wrong. It needs to be in the dt-schema > > > > repository, not strictly "the kernel". For example, bootph-all (etc) > > > > are in dt-schema and so can be in the upstream kernel but are not used > > > > in the kernel itself. > > > > > > > > > There is a solution for this which is deleting the node we don't want > > > > > to pass to > > > > > the kernel using delete-node in the U-Boot DT. > > > > > > > > Something like this will likely be needed, in the end, at least for some > > > > cases. But the goal is that everything gets in to dt-schema. > > > > > > We are already working on U-Boot on that. The idea is rather simple. > > > We will have an array with nodes and node entries. Before we boot up > > > we'll scan that array, if a node entry exists we will delete that, > > > otherwise we will just get rid of the entire node. That should be > > > pretty easy to maintain and extend. U-Boot will then be able to use > > > it;s internal bidings without polluting the DT we handover to the > > > kernel. > > > > This is not pollution - we have moved past that now and Linux has > > accepted some U-Boot bindings. This is the DT and if there are things > > in it that are not related to Linux, it can ignore them. > > > > We should add whatever bindings we need to make U-Boot work > > efficiently and correctly. > > > > The cases that are already accepted make sense. Things like the > public part of the certificates used to authenticate capsule updates > or the encoding of the recent a/b update nodes are not needed in any > way in an OS. Those don't make sense to upstream and those are > polluting the DT and need stripping
It doesn't matter that Linux doesn't *need* it. If it is there it will have to accommodate it. We have loads of Linux stuff in the DT that means nothing to U-Boot. Many of the bindings chosen by Linux are wildly inefficient for U-Boot to implement. We don't need to strip anything. This is not pollution. It is a binding agreement between projects. Regards, Simon
