Re: [PATCH v3 4/4] efi: payload: make CONFIG_STATE_OVERLAY (and BareboxState export) work on x86

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

On 8/25/26 5:05 AM, chalianis1@gmail.com wrote:
> From: Chali Anis <chalianis1@gmail.com>
> 
> barebox_register_of() - the only thing that ever registers a live
> devicetree root pre-boot on x86 EFI - lived in boarddata.c, which was
> compiled solely for CONFIG_EFI_STUB (the chain-loaded/ARM handoff-data
> entry point). x86 uses CONFIG_EFI_PAYLOAD (entry-single.c's standalone
> efi_main()), so no code ever called it there: of_get_root_node() stayed
> NULL for the entire pre-boot sequence. That's what state_overlay_apply()
> (CONFIG_STATE_OVERLAY's postcore_initcall) and state_to_efivars_export()
> (the BareboxState UEFI variable export) both rely on, so neither ever
> had anything to work with on x86. Compile boarddata.o for
> CONFIG_EFI_PAYLOAD too - efi_register_of() only needs BS, which
> entry-single.c's efi_main() already sets before any initcall runs, and
> handle_efi_boarddata() already no-ops cleanly when there is no PBL
> handoff data, the normal case for this entry point.
> 
> On x86, actually binding a struct state to the node CONFIG_STATE_OVERLAY
> adds still needs a fresh of_probe() pass: barebox_register_of() already
> ran one, before the overlay added anything, and the next one needs to
> happen later still than state_overlay_apply()'s own postcore_initcall,
> too - PCI/SATA enumeration (and thus the disk cdevs a partuuid-based
> state backend resolves against) only completes well after that point.
> Add efi_devices_probe() at device_efi_initcall to cover it.
> 
> Finally, now that a state node reachable via CONFIG_STATE_OVERLAY is
> something x86 can actually end up with pre-boot, add efi_late_init()'s
> "skip loading the standalone state.dtb whenever a 'state' alias is
> already present" check - it's only meaningful once that can happen.
> 
> Tested on QEMU as the EFI payload with a partuuid-referenced backend.
> 
> Assisted-by: Claude Sonnet 5
> Signed-off-by: Chali Anis <chalianis1@gmail.com>
> ---
>  efi/payload/Makefile |  1 +
>  efi/payload/init.c   | 18 +++++++++++++++++-
>  2 files changed, 18 insertions(+), 1 deletion(-)
> 
> diff --git a/efi/payload/Makefile b/efi/payload/Makefile
> index 6306540ab595..f8b19428a99c 100644
> --- a/efi/payload/Makefile
> +++ b/efi/payload/Makefile
> @@ -11,3 +11,4 @@ obj-pbl-$(CONFIG_EFI_PAYLOAD) += early-mem.o
>  obj-$(CONFIG_EFI_PAYLOAD) += entry-single.o
>  pbl-$(CONFIG_EFI_STUB) += entry-multi.o
>  obj-$(CONFIG_EFI_STUB) += boarddata.o
> +obj-$(CONFIG_EFI_PAYLOAD) += boarddata.o
> diff --git a/efi/payload/init.c b/efi/payload/init.c
> index cdb73afffa2c..e644ec60bb87 100644
> --- a/efi/payload/init.c
> +++ b/efi/payload/init.c
> @@ -355,7 +355,7 @@ static int efi_late_init(void)
>  	void *fdt;
>  	int ret;
>  
> -	if (!IS_ENABLED(CONFIG_STATE))
> +	if (!IS_ENABLED(CONFIG_STATE) || of_find_node_by_alias(NULL, "state"))
>  		return 0;
>  
>  	if (!get_mounted_path("/boot")) {
> @@ -453,6 +453,22 @@ static int state_to_efivars_export(void)
>  	return ret;
>  }
>  late_efi_initcall(state_to_efivars_export);
> +
> +/*
> + * On x86, PCI/SATA enumeration (and thus the disk cdevs a partuuid-based
> + * state backend resolves against) only completes well after the one
> + * of_probe() pass barebox_register_of() already did, before the state
> + * overlay even added its node. Re-probe once devices have actually shown
> + * up, so such a backend can still bind.
> + */

This comment makes no sense. Block devices we boot from under EFI are
usually EFI block devices. We don't have PCI/SATA drivers even in barebox.


> +static int __maybe_unused efi_devices_probe(void)
> +{
> +	return of_probe();
> +}
> +#if IS_ENABLED(CONFIG_X86)
> +device_efi_initcall(efi_devices_probe);
> +#endif
> +
>  static int do_efiexit(int argc, char *argv[])
>  {
>  	if (!BS)
> 

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