From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E5D9F35BDC3 for ; Fri, 14 Nov 2025 21:35:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763156134; cv=none; b=PRakaGP2TpehMTvGHNQAgCiUPdQM4E0CNSSUvksfF97IChYkpCXbrsepx+M6QL+n1X6ySeN0PxmB2mCE3/Vaks/c3J9wFVYBP0X6pVW9kwubg466eD+o6uaPZhHKUePX6DR0JiJFcMd/uH5eCMyoPRBUVjsPxZWodmm/oVZxzbI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763156134; c=relaxed/simple; bh=1N55a/jSP1C06S2+q+w3uHnxztFGwmkvbD4nef6FCfI=; h=Date:To:From:Subject:Message-Id; b=IYR6jWj4kQUOYYFqNQBEWDY1EBeXHrFZM0RfRXaIydGtdRum3H+KArnMYx3xIPxj5PC783le4XHbpLQsWTM+Wc5pnRhj0QLcRS0JkZjxuZ4qT4+cyzWIXLXVqJJTvFy1ZQz3WcrrSu7dW2kFbyyIFxFDyUjaOw627VKHcY2FyGk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=LeNGpV15; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="LeNGpV15" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B74F4C4CEF8; Fri, 14 Nov 2025 21:35:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1763156133; bh=1N55a/jSP1C06S2+q+w3uHnxztFGwmkvbD4nef6FCfI=; h=Date:To:From:Subject:From; b=LeNGpV15B09SYlLRKNs7IFwtL4H6y1P/j+9m2F3TNrOndNGa78imWY0FAumLAv3yE QmSgsdBQRO4ewr86ygK+XHUo1AetmAy0S/ZCsyGll/DEKcOGFUyh9jyW667MxZCOJi XvmHkIvBNJjsJlxISfl4zLAL7HkZ1gxCYLM/EWZg= Date: Fri, 14 Nov 2025 13:35:32 -0800 To: mm-commits@vger.kernel.org,rppt@kernel.org,pratyush@kernel.org,kees@kernel.org,graf@amazon.com,ebiggers@google.com,dave@vasilevsky.ca,coxu@redhat.com,bhe@redhat.com,arnd@arndb.de,pasha.tatashin@soleen.com,akpm@linux-foundation.org From: Andrew Morton Subject: + kho-update-fdt-dynamically-for-subtree-addition-removal.patch added to mm-nonmm-unstable branch Message-Id: <20251114213533.B74F4C4CEF8@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: kho: update FDT dynamically for subtree addition/removal has been added to the -mm mm-nonmm-unstable branch. Its filename is kho-update-fdt-dynamically-for-subtree-addition-removal.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/kho-update-fdt-dynamically-for-subtree-addition-removal.patch This patch will later appear in the mm-nonmm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Pasha Tatashin Subject: kho: update FDT dynamically for subtree addition/removal Date: Fri, 14 Nov 2025 13:59:59 -0500 Currently, sub-FDTs were tracked in a list (kho_out.sub_fdts) and the final FDT is constructed entirely from scratch during kho_finalize(). We can maintain the FDT dynamically: 1. Initialize a valid, empty FDT in kho_init(). 2. Use fdt_add_subnode and fdt_setprop in kho_add_subtree to update the FDT immediately when a subsystem registers. 3. Use fdt_del_node in kho_remove_subtree to remove entries. This removes the need for the intermediate sub_fdts list and the reconstruction logic in kho_finalize(). kho_finalize() now only needs to trigger memory map serialization. Link: https://lkml.kernel.org/r/20251114190002.3311679-11-pasha.tatashin@soleen.com Signed-off-by: Pasha Tatashin Reviewed-by: Mike Rapoport (Microsoft) Reviewed-by: Pratyush Yadav Cc: Alexander Graf Cc: Arnd Bergmann Cc: Baoquan He Cc: Coiby Xu Cc: Dave Vasilevsky Cc: Eric Biggers Cc: Kees Cook Signed-off-by: Andrew Morton --- kernel/liveupdate/kexec_handover.c | 144 ++++++++++++--------------- 1 file changed, 69 insertions(+), 75 deletions(-) --- a/kernel/liveupdate/kexec_handover.c~kho-update-fdt-dynamically-for-subtree-addition-removal +++ a/kernel/liveupdate/kexec_handover.c @@ -104,20 +104,11 @@ struct kho_mem_track { struct khoser_mem_chunk; -struct kho_sub_fdt { - struct list_head l; - const char *name; - void *fdt; -}; - struct kho_out { void *fdt; bool finalized; struct mutex lock; /* protects KHO FDT finalization */ - struct list_head sub_fdts; - struct mutex fdts_lock; - struct kho_mem_track track; struct kho_debugfs dbg; }; @@ -127,8 +118,6 @@ static struct kho_out kho_out = { .track = { .orders = XARRAY_INIT(kho_out.track.orders, 0), }, - .sub_fdts = LIST_HEAD_INIT(kho_out.sub_fdts), - .fdts_lock = __MUTEX_INITIALIZER(kho_out.fdts_lock), .finalized = false, }; @@ -725,37 +714,67 @@ err_disable_kho: */ int kho_add_subtree(const char *name, void *fdt) { - struct kho_sub_fdt *sub_fdt; + phys_addr_t phys = virt_to_phys(fdt); + void *root_fdt = kho_out.fdt; + int err = -ENOMEM; + int off, fdt_err; - sub_fdt = kmalloc(sizeof(*sub_fdt), GFP_KERNEL); - if (!sub_fdt) - return -ENOMEM; + guard(mutex)(&kho_out.lock); + + fdt_err = fdt_open_into(root_fdt, root_fdt, PAGE_SIZE); + if (fdt_err < 0) + return err; + + off = fdt_add_subnode(root_fdt, 0, name); + if (off < 0) { + if (off == -FDT_ERR_EXISTS) + err = -EEXIST; + goto out_pack; + } - INIT_LIST_HEAD(&sub_fdt->l); - sub_fdt->name = name; - sub_fdt->fdt = fdt; + err = fdt_setprop(root_fdt, off, PROP_SUB_FDT, &phys, sizeof(phys)); + if (err < 0) + goto out_pack; - guard(mutex)(&kho_out.fdts_lock); - list_add_tail(&sub_fdt->l, &kho_out.sub_fdts); WARN_ON_ONCE(kho_debugfs_fdt_add(&kho_out.dbg, name, fdt, false)); - return 0; +out_pack: + fdt_pack(root_fdt); + + return err; } EXPORT_SYMBOL_GPL(kho_add_subtree); void kho_remove_subtree(void *fdt) { - struct kho_sub_fdt *sub_fdt; + phys_addr_t target_phys = virt_to_phys(fdt); + void *root_fdt = kho_out.fdt; + int off; + int err; + + guard(mutex)(&kho_out.lock); + + err = fdt_open_into(root_fdt, root_fdt, PAGE_SIZE); + if (err < 0) + return; - guard(mutex)(&kho_out.fdts_lock); - list_for_each_entry(sub_fdt, &kho_out.sub_fdts, l) { - if (sub_fdt->fdt == fdt) { - list_del(&sub_fdt->l); - kfree(sub_fdt); + for (off = fdt_first_subnode(root_fdt, 0); off >= 0; + off = fdt_next_subnode(root_fdt, off)) { + const u64 *val; + int len; + + val = fdt_getprop(root_fdt, off, PROP_SUB_FDT, &len); + if (!val || len != sizeof(phys_addr_t)) + continue; + + if ((phys_addr_t)*val == target_phys) { + fdt_del_node(root_fdt, off); kho_debugfs_fdt_remove(&kho_out.dbg, fdt); break; } } + + fdt_pack(root_fdt); } EXPORT_SYMBOL_GPL(kho_remove_subtree); @@ -1232,48 +1251,6 @@ void kho_restore_free(void *mem) } EXPORT_SYMBOL_GPL(kho_restore_free); -static int __kho_finalize(void) -{ - void *root = kho_out.fdt; - struct kho_sub_fdt *fdt; - u64 empty_mem_map = 0; - int err; - - err = fdt_create(root, PAGE_SIZE); - err |= fdt_finish_reservemap(root); - err |= fdt_begin_node(root, ""); - err |= fdt_property_string(root, "compatible", KHO_FDT_COMPATIBLE); - err |= fdt_property(root, PROP_PRESERVED_MEMORY_MAP, &empty_mem_map, - sizeof(empty_mem_map)); - if (err) - goto err_exit; - - mutex_lock(&kho_out.fdts_lock); - list_for_each_entry(fdt, &kho_out.sub_fdts, l) { - phys_addr_t phys = virt_to_phys(fdt->fdt); - - err |= fdt_begin_node(root, fdt->name); - err |= fdt_property(root, PROP_SUB_FDT, &phys, sizeof(phys)); - err |= fdt_end_node(root); - } - mutex_unlock(&kho_out.fdts_lock); - - err |= fdt_end_node(root); - err |= fdt_finish(root); - if (err) - goto err_exit; - - err = kho_mem_serialize(&kho_out); - if (err) - goto err_exit; - - return 0; - -err_exit: - pr_err("Failed to convert KHO state tree: %d\n", err); - return err; -} - int kho_finalize(void) { int ret; @@ -1282,12 +1259,7 @@ int kho_finalize(void) return -EOPNOTSUPP; guard(mutex)(&kho_out.lock); - if (kho_out.finalized) { - kho_update_memory_map(NULL); - kho_out.finalized = false; - } - - ret = __kho_finalize(); + ret = kho_mem_serialize(&kho_out); if (ret) return ret; @@ -1372,6 +1344,24 @@ int kho_retrieve_subtree(const char *nam } EXPORT_SYMBOL_GPL(kho_retrieve_subtree); +static __init int kho_out_fdt_setup(void) +{ + void *root = kho_out.fdt; + u64 empty_mem_map = 0; + int err; + + err = fdt_create(root, PAGE_SIZE); + err |= fdt_finish_reservemap(root); + err |= fdt_begin_node(root, ""); + err |= fdt_property_string(root, "compatible", KHO_FDT_COMPATIBLE); + err |= fdt_property(root, PROP_PRESERVED_MEMORY_MAP, &empty_mem_map, + sizeof(empty_mem_map)); + err |= fdt_end_node(root); + err |= fdt_finish(root); + + return err; +} + static __init int kho_init(void) { const void *fdt = kho_get_fdt(); @@ -1394,6 +1384,10 @@ static __init int kho_init(void) if (err) goto err_free_fdt; + err = kho_out_fdt_setup(); + if (err) + goto err_free_fdt; + if (fdt) { kho_in_debugfs_init(&kho_in.dbg, fdt); return 0; _ Patches currently in -mm which might be from pasha.tatashin@soleen.com are lib-test_kho-check-if-kho-is-enabled.patch kho-make-debugfs-interface-optional.patch kho-add-interfaces-to-unpreserve-folios-page-ranges-and-vmalloc.patch memblock-unpreserve-memory-in-case-of-error.patch test_kho-unpreserve-memory-in-case-of-error.patch kho-dont-unpreserve-memory-during-abort.patch liveupdate-kho-move-to-kernel-liveupdate.patch liveupdate-kho-move-to-kernel-liveupdate-fix.patch maintainers-update-kho-maintainers.patch kho-fix-misleading-log-message-in-kho_populate.patch kho-convert-__kho_abort-to-return-void.patch kho-introduce-high-level-memory-allocation-api.patch kho-preserve-fdt-folio-only-once-during-initialization.patch kho-verify-deserialization-status-and-fix-fdt-alignment-access.patch kho-always-expose-output-fdt-in-debugfs.patch kho-simplify-serialization-and-remove-__kho_abort.patch kho-remove-global-preserved_mem_map-and-store-state-in-fdt.patch kho-remove-abort-functionality-and-support-state-refresh.patch kho-update-fdt-dynamically-for-subtree-addition-removal.patch kho-allow-kexec-load-before-kho-finalization.patch kho-allow-memory-preservation-state-updates-after-finalization.patch kho-add-kconfig-option-to-enable-kho-by-default.patch liveupdate-luo_core-luo_ioctl-live-update-orchestrator.patch liveupdate-luo_core-integrate-with-kho.patch reboot-call-liveupdate_reboot-before-kexec.patch liveupdate-luo_session-add-sessions-support.patch liveupdate-luo_ioctl-add-user-interface.patch liveupdate-luo_file-implement-file-systems-callbacks.patch liveupdate-luo_session-add-ioctls-for-file-preservation-and-state-management.patch liveupdate-luo_flb-introduce-file-lifecycle-bound-global-state.patch docs-add-luo-documentation.patch maintainers-add-liveupdate-entry.patch selftests-liveupdate-add-userspace-api-selftests.patch selftests-liveupdate-add-kexec-based-selftest-for-session-lifecycle.patch selftests-liveupdate-add-kexec-test-for-multiple-and-empty-sessions.patch tests-liveupdate-add-in-kernel-liveupdate-test.patch