On Sat, Nov 22 2025, Pasha Tatashin wrote:

Integrate the LUO with the KHO framework to enable passing LUO state
across a kexec reboot.

This patch implements the lifecycle integration with KHO:

1. Incoming State: During early boot (`early_initcall`), LUO checks if
   KHO is active. If so, it retrieves the "LUO" subtree, verifies the
   "luo-v1" compatibility string, and reads the `liveupdate-number` to
   track the update count.

2. Outgoing State: During late initialization (`late_initcall`), LUO
   allocates a new FDT for the next kernel, populates it with the basic
   header (compatible string and incremented update number), and
   registers it with KHO (`kho_add_subtree`).

3. Finalization: The `liveupdate_reboot()` notifier is updated to invoke
   `kho_finalize()`. This ensures that all memory segments marked for
   preservation are properly serialized before the kexec jump.

LUO now depends on `CONFIG_KEXEC_HANDOVER`.

Nit: This patch does not add the dependency. That is done by patch 1. I
guess that change needs to be moved here or the comment removed?

Other than this,

Reviewed-by: Pratyush Yadav <pratyush@kernel.org>

[...]

-- 
Regards,
Pratyush Yadav