These patches are taken from the LUOv4 series [1] and address recent
comments from Pratyush.
This series refactors the KHO framework to better support in-kernel
users like the upcoming LUO. The current design, which relies on a
notifier chain and debugfs for control, is too restrictive for direct
programmatic use.
The core of this rework is the removal of the notifier chain in favor of
a direct registration API. This decouples clients from the shutdown-time
finalization sequence, allowing them to manage their preserved state
more flexibly and at any time.
In support of this new model, this series also:
- Exports kho_finalize() and kho_abort() for programmatic control.
- Makes the debugfs interface optional.
- Introduces APIs to unpreserve memory and fixes a bug in the abort
path where client state was being incorrectly discarded. Note that
this is an interim step, as a more comprehensive fix is planned as
part of the stateless KHO work [2].
- Moves all KHO code into a new kernel/liveupdate/ directory to
consolidate live update components.
[1] https://lore.kernel.org/all/20250929010321.3462457-1-pasha.tatashin@soleen.com
[2] https://lore.kernel.org/all/20251001011941.1513050-1-jasonmiu@google.com
Mike Rapoport (Microsoft) (1):
kho: drop notifiers
Pasha Tatashin (6):
kho: allow to drive kho from within kernel
kho: make debugfs interface optional
kho: add interfaces to unpreserve folios and page ranes
kho: don't unpreserve memory during abort
liveupdate: kho: move to kernel/liveupdate
kho: move kho debugfs directory to liveupdate
Documentation/core-api/kho/concepts.rst | 2 +-
MAINTAINERS | 3 +-
include/linux/kexec_handover.h | 53 +-
init/Kconfig | 2 +
kernel/Kconfig.kexec | 15 -
kernel/Makefile | 2 +-
kernel/liveupdate/Kconfig | 30 ++
kernel/liveupdate/Makefile | 4 +
kernel/{ => liveupdate}/kexec_handover.c | 515 ++++++++------------
kernel/liveupdate/kexec_handover_debug.c | 216 ++++++++
kernel/liveupdate/kexec_handover_internal.h | 47 ++
lib/test_kho.c | 30 +-
mm/memblock.c | 60 +--
tools/testing/selftests/kho/init.c | 2 +-
tools/testing/selftests/kho/vmtest.sh | 1 +
15 files changed, 553 insertions(+), 429 deletions(-)
create mode 100644 kernel/liveupdate/Kconfig
create mode 100644 kernel/liveupdate/Makefile
rename kernel/{ => liveupdate}/kexec_handover.c (79%)
create mode 100644 kernel/liveupdate/kexec_handover_debug.c
create mode 100644 kernel/liveupdate/kexec_handover_internal.h
base-commit: 4a71531471926e3c391665ee9c42f4e0295a4585
--
2.51.0.618.g983fd99d29-goog