On Tue, Nov 25, 2025 at 11:58:32AM -0500, 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.

Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: Pratyush Yadav <pratyush@kernel.org>

Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>

---
 include/linux/kho/abi/luo.h      |  58 ++++++++++++
 kernel/liveupdate/luo_core.c     | 154 ++++++++++++++++++++++++++++++-
 kernel/liveupdate/luo_internal.h |  22 +++++
 3 files changed, 233 insertions(+), 1 deletion(-)
 create mode 100644 include/linux/kho/abi/luo.h
 create mode 100644 kernel/liveupdate/luo_internal.h

-- 
Sincerely yours,
Mike.