Re: [PATCH v3 3/4] efi: payload: export resolved state as a BareboxState UEFI variable

[anis chali <chalianis1@gmail.com>]

Hi,

Le mar. 25 août 2026 à 19:04, Ahmad Fatoum <a.fatoum@pengutronix.de> a écrit :
>
> Hi,
>
> On 8/25/26 5:05 AM, chalianis1@gmail.com wrote:
> > From: Chali Anis <chalianis1@gmail.com>
> >
> > When a "barebox,state" node is already reachable via barebox's live
> > devicetree (statically compiled in, or injected by
> > CONFIG_STATE_OVERLAY), render its fully resolved description - backend
> > phandle included - with of_state_fixup() and publish it as a
> > "BareboxState" UEFI variable, so an OS-side consumer can locate the
> > state layout without needing a separate state.dtb file on the ESP.
>
> Why not pass along the whole barebox DT? For EFI payloads, that's
> effectively the state and the backend already and in case we gain more
> content in future, it will just be passed along as well.
I understand, so we should call the efivar BareboxDT-XXXXX ??
or If we keep the variable name BareboxState and pass the entire device tree,
going forward we would only support state definitions within the barebox DT
in efi payloads???

> >
> > state_to_efivars_export() and efi_late_init() are both late_efi_initcall,
> > and within one initcall level, execution follows definition order in the
> > object file, so state_to_efivars_export() must be defined after
> > efi_late_init(): on boards with no state node in their own static
> > devicetree, efi_late_init() is what loads and registers
> > /boot/EFI/barebox/state.dtb, and only once that has had a chance to run
> > does state_by_alias() have anything to find. Defined the other way
> > around, state_to_efivars_export() would always run first and never see
> > a state.dtb efi_late_init() had not loaded yet - it would only have
> > happened to work when CONFIG_STATE_OVERLAY had already registered the
> > node much earlier, at postcore_initcall, a narrower case than the
> > state.dtb fallback efi_late_init() exists to support.
> >
> > Look the state instance up via the state_by_alias() helper
> > (common/state/state.c) rather than open-coding the equivalent
> > of_find_node_by_alias() + state_by_node(). This also means state not
> > being set up yet is just a clean no-op, rather than the -ENODEV that
> > open-coded version returned, which would've been logged as an initcall
> > failure for what is an entirely ordinary condition.
> >
> > Assisted-by: Claude Sonnet 5
> > Signed-off-by: Chali Anis <chalianis1@gmail.com>
> > ---
> >  efi/payload/init.c | 51 +++++++++++++++++++++++++++++++++++++++++++++-
> >  1 file changed, 50 insertions(+), 1 deletion(-)
> >
> > diff --git a/efi/payload/init.c b/efi/payload/init.c
> > index f0ce2a82cefc..cdb73afffa2c 100644
> > --- a/efi/payload/init.c
> > +++ b/efi/payload/init.c
> > @@ -287,7 +287,6 @@ core_efi_initcall(efi_register_firmware_nodes_fixup);
> >  #define EFI_LOADER_FEATURE_SECUREBOOT_ENROLL       (1LL << 11)
> >  #define EFI_LOADER_FEATURE_RETAIN_SHIM             (1LL << 12)
> >
> > -
> >  static int efi_postcore_init(void)
> >  {
> >       const struct efi_device_path *parent_image_dp, *loaded_image_dp;
> > @@ -404,6 +403,56 @@ static int efi_late_init(void)
> >  }
> >  late_efi_initcall(efi_late_init);
> >
> > +/*
> > + * Must run after efi_late_init(): on boards with no state node compiled
> > + * into their own devicetree, efi_late_init() is what loads and registers
> > + * /boot/EFI/barebox/state.dtb (or, on CONFIG_STATE_OVERLAY targets, that
> > + * already happened much earlier). Only once that has had a chance to run
> > + * does state_by_alias() have anything to find here.
> > + */
> > +static int state_to_efivars_export(void)
> > +{
> > +     struct device_node *np;
> > +     struct state *state;
> > +     void *fdt;
> > +     size_t size;
> > +     int ret;
> > +
> > +     if (!IS_ENABLED(CONFIG_STATE))
> > +             return 0;
> > +
> > +     state = state_by_alias("state");
> > +     if (!state)
> > +             return 0;
> > +
> > +     np = of_new_node(NULL, NULL);
> > +     if (!np)
> > +             return -ENOMEM;
> > +
> > +     ret = of_state_fixup(np, state);
> > +     if (ret)
> > +             goto out;
> > +
> > +     fdt = of_flatten_dtb(np);
> > +     if (!fdt) {
> > +             ret = -ENOMEM;
> > +             goto out;
> > +     }
> > +
> > +     size = fdt_totalsize(fdt);
> > +
> > +     efi_set_variable("BareboxState", &efi_barebox_vendor_guid,
> > +                       EFI_VARIABLE_BOOTSERVICE_ACCESS |
> > +                       EFI_VARIABLE_RUNTIME_ACCESS,
> > +                       fdt, size);
> > +
> > +     free(fdt);
> > +     ret = 0;
> > +out:
> > +     of_delete_node(np);
> > +     return ret;
> > +}
> > +late_efi_initcall(state_to_efivars_export);
> >  static int do_efiexit(int argc, char *argv[])
> >  {
> >       if (!BS)
> >
>
> --
> Pengutronix e.K.                  |                             |
> Steuerwalder Str. 21              | http://www.pengutronix.de/  |
> 31137 Hildesheim, Germany         | Phone: +49-5121-206917-0    |
> Amtsgericht Hildesheim, HRA 2686  | Fax:   +49-5121-206917-5555 |
>

best regards.
Anis