linux/tools/testing
Pasha Tatashin 03d3963464 kho: make debugfs interface optional
Patch series "liveupdate: Rework KHO for in-kernel users", v9.

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:
 - 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 [1].
 - Moves all KHO code into a new kernel/liveupdate/ directory to
   consolidate live update components.


This patch (of 9):

Currently, KHO is controlled via debugfs interface, but once LUO is
introduced, it can control KHO, and the debug interface becomes optional.

Add a separate config CONFIG_KEXEC_HANDOVER_DEBUGFS that enables the
debugfs interface, and allows to inspect the tree.

Move all debugfs related code to a new file to keep the .c files clear of
ifdefs.

Link: https://lkml.kernel.org/r/20251101142325.1326536-1-pasha.tatashin@soleen.com
Link: https://lkml.kernel.org/r/20251101142325.1326536-2-pasha.tatashin@soleen.com
Link: https://lore.kernel.org/all/20251020100306.2709352-1-jasonmiu@google.com [1]
Co-developed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: Pratyush Yadav <pratyush@kernel.org>
Cc: Alexander Graf <graf@amazon.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Changyuan Lyu <changyuanl@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Simon Horman <horms@kernel.org>
Cc: Zhu Yanjun <yanjun.zhu@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-27 14:24:31 -08:00
..
crypto/chacha20-s390
cxl Merge branch 'for-6.18/cxl-delay-dport' into cxl-for-next 2025-09-18 14:34:51 -07:00
fault-injection
ktest ktest.pl: Add new PATCHCHECK_SKIP option to skip testing individual commits 2025-07-29 09:30:08 -04:00
kunit kunit: qemu_configs: Add MIPS configurations 2025-09-15 10:30:07 -06:00
memblock
nvdimm nvdimm: ndtest: Return -ENOMEM if devm_kcalloc() fails in ndtest_probe() 2025-09-25 12:49:46 -05:00
radix-tree Patch series in this pull request: 2025-10-02 18:44:54 -07:00
rbtree
scatterlist mm: remove nth_page() 2025-09-21 14:22:10 -07:00
selftests kho: make debugfs interface optional 2025-11-27 14:24:31 -08:00
shared Summary of significant series in this pull request: 2025-10-02 18:18:33 -07:00
vma Summary of significant series in this pull request: 2025-10-02 18:18:33 -07:00
vsock vsock/test: Remove redundant semicolons 2025-08-29 19:10:52 -07:00