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 91E891A23A4 for ; Thu, 9 Oct 2025 02:15:02 +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=1759976102; cv=none; b=f+GTNj2YwqIxhnjtvCOp6SBMDdfY6oOVX9lbHKIFF8WIUDbUU0ixjs2Gz0aB9AzN/EUeh4yH6EMkQr4BuBf0EPH6YwEZWb8d6wVqpJLp1y+0bf9WZI6VXPQZ6+W6qvIxg3l9VvToYV2Jf7po3tMoFFxqN9fFSrWye7LMc6seWKE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759976102; c=relaxed/simple; bh=Dr+JdqLiUyltRy/9i/YoYRKWUYENsDV83k8ZusDXmU8=; h=Date:To:From:Subject:Message-Id; b=Ae9FXcQXsoi4flrct4vap7Z81sxX9T62E5XB88c25Ph3EX0f7Azm6HX4ojCdwNs3JXntx4SqTVQZIoAOPXn1ZGBe/IfgHWIbBZP3sFolQriM5g2zoHVKiMrj+/5qUpabI6+9AxU63hXYJZ8TIJ5/6CvmvIEqlNJ0byKGaxN20Yw= 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=Y2yTv+PY; 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="Y2yTv+PY" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0ED4FC4CEE7; Thu, 9 Oct 2025 02:15:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1759976102; bh=Dr+JdqLiUyltRy/9i/YoYRKWUYENsDV83k8ZusDXmU8=; h=Date:To:From:Subject:From; b=Y2yTv+PYc1NYCrBxp8Sn1tZeEffVuT7E3MIa5VWUzNIMEPEkRCEE5gOesGAEEowjL 5X6BDoMMmJgYSLPQJX1YJSV78KYiBnjtqnGjZbxWZxnokl56u/3W+MOjpkxplWEtp/ oeU8L5BrqUlUKscv7Hx/UZCprXimbmoxguPXges0= Date: Wed, 08 Oct 2025 19:15:01 -0700 To: mm-commits@vger.kernel.org,tj@kernel.org,rppt@kernel.org,rdunlap@infradead.org,pratyush@kernel.org,ojeda@kernel.org,masahiroy@kernel.org,jgg@ziepe.ca,jgg@nvidia.com,graf@amazon.com,corbet@lwn.net,brauner@kernel.org,pasha.tatashin@soleen.com,akpm@linux-foundation.org From: Andrew Morton Subject: + kho-make-debugfs-interface-optional.patch added to mm-nonmm-unstable branch Message-Id: <20251009021502.0ED4FC4CEE7@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: kho: make debugfs interface optional has been added to the -mm mm-nonmm-unstable branch. Its filename is kho-make-debugfs-interface-optional.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/kho-make-debugfs-interface-optional.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: make debugfs interface optional Date: Tue, 7 Oct 2025 03:30:55 +0000 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/20251007033100.836886-3-pasha.tatashin@soleen.com Co-developed-by: Mike Rapoport (Microsoft) Signed-off-by: Mike Rapoport (Microsoft) Signed-off-by: Pasha Tatashin Cc: Alexander Graf Cc: Christian Brauner Cc: Jason Gunthorpe Cc: Jason Gunthorpe Cc: Jonathan Corbet Cc: Masahiro Yamada Cc: Miguel Ojeda Cc: Pratyush Yadav Cc: Randy Dunlap Cc: Tejun Heo Signed-off-by: Andrew Morton --- MAINTAINERS | 3 kernel/Kconfig.kexec | 10 + kernel/Makefile | 1 kernel/kexec_handover.c | 223 ++---------------------- kernel/kexec_handover_debug.c | 213 ++++++++++++++++++++++ kernel/kexec_handover_internal.h | 44 ++++ tools/testing/selftests/kho/vmtest.sh | 1 7 files changed, 290 insertions(+), 205 deletions(-) --- a/kernel/Kconfig.kexec~kho-make-debugfs-interface-optional +++ a/kernel/Kconfig.kexec @@ -109,6 +109,16 @@ config KEXEC_HANDOVER to keep data or state alive across the kexec. For this to work, both source and target kernels need to have this option enabled. +config KEXEC_HANDOVER_DEBUGFS + bool "kexec handover debugfs interface" + depends on KEXEC_HANDOVER + depends on DEBUG_FS + help + Allow to control kexec handover device tree via debugfs + interface, i.e. finalize the state or aborting the finalization. + Also, enables inspecting the KHO fdt trees with the debugfs binary + blobs. + config CRASH_DUMP bool "kernel crash dumps" default ARCH_DEFAULT_CRASH_DUMP --- a/kernel/kexec_handover.c~kho-make-debugfs-interface-optional +++ a/kernel/kexec_handover.c @@ -10,7 +10,6 @@ #include #include -#include #include #include #include @@ -28,6 +27,7 @@ */ #include "../mm/internal.h" #include "kexec_internal.h" +#include "kexec_handover_internal.h" #define KHO_FDT_COMPATIBLE "kho-v1" #define PROP_PRESERVED_MEMORY_MAP "preserved-memory-map" @@ -101,8 +101,6 @@ struct khoser_mem_chunk; struct kho_serialization { struct page *fdt; - struct list_head fdt_list; - struct dentry *sub_fdt_dir; struct kho_mem_track track; /* First chunk of serialized preserved memory map */ struct khoser_mem_chunk *preserved_mem_map; @@ -110,20 +108,16 @@ struct kho_serialization { struct kho_out { struct blocking_notifier_head chain_head; - - struct dentry *dir; - struct mutex lock; /* protects KHO FDT finalization */ - struct kho_serialization ser; bool finalized; + struct kho_debugfs dbg; }; static struct kho_out kho_out = { .chain_head = BLOCKING_NOTIFIER_INIT(kho_out.chain_head), .lock = __MUTEX_INITIALIZER(kho_out.lock), .ser = { - .fdt_list = LIST_HEAD_INIT(kho_out.ser.fdt_list), .track = { .orders = XARRAY_INIT(kho_out.ser.track.orders, 0), }, @@ -465,8 +459,8 @@ static void __init kho_mem_deserialize(c * area for early allocations that happen before page allocator is * initialized. */ -static struct kho_scratch *kho_scratch; -static unsigned int kho_scratch_cnt; +struct kho_scratch *kho_scratch; +unsigned int kho_scratch_cnt; /* * The scratch areas are scaled by default as percent of memory allocated from @@ -662,37 +656,6 @@ err_disable_kho: kho_enable = false; } -struct fdt_debugfs { - struct list_head list; - struct debugfs_blob_wrapper wrapper; - struct dentry *file; -}; - -static int kho_debugfs_fdt_add(struct list_head *list, struct dentry *dir, - const char *name, const void *fdt) -{ - struct fdt_debugfs *f; - struct dentry *file; - - f = kmalloc(sizeof(*f), GFP_KERNEL); - if (!f) - return -ENOMEM; - - f->wrapper.data = (void *)fdt; - f->wrapper.size = fdt_totalsize(fdt); - - file = debugfs_create_blob(name, 0400, dir, &f->wrapper); - if (IS_ERR(file)) { - kfree(f); - return PTR_ERR(file); - } - - f->file = file; - list_add(&f->list, list); - - return 0; -} - /** * kho_add_subtree - record the physical address of a sub FDT in KHO root tree. * @ser: serialization control object passed by KHO notifiers. @@ -704,7 +667,8 @@ static int kho_debugfs_fdt_add(struct li * by KHO for the new kernel to retrieve it after kexec. * * A debugfs blob entry is also created at - * ``/sys/kernel/debug/kho/out/sub_fdts/@name``. + * ``/sys/kernel/debug/kho/out/sub_fdts/@name`` when kernel is configured with + * CONFIG_KEXEC_HANDOVER_DEBUGFS * * Return: 0 on success, error code on failure */ @@ -721,7 +685,7 @@ int kho_add_subtree(struct kho_serializa if (err) return err; - return kho_debugfs_fdt_add(&ser->fdt_list, ser->sub_fdt_dir, name, fdt); + return kho_debugfs_fdt_add(&kho_out.dbg, name, fdt, false); } EXPORT_SYMBOL_GPL(kho_add_subtree); @@ -1044,29 +1008,6 @@ err_free_pages_array: } EXPORT_SYMBOL_GPL(kho_restore_vmalloc); -/* Handling for debug/kho/out */ - -static struct dentry *debugfs_root; - -static int kho_out_update_debugfs_fdt(void) -{ - int err = 0; - struct fdt_debugfs *ff, *tmp; - - if (kho_out.finalized) { - err = kho_debugfs_fdt_add(&kho_out.ser.fdt_list, kho_out.dir, - "fdt", page_to_virt(kho_out.ser.fdt)); - } else { - list_for_each_entry_safe(ff, tmp, &kho_out.ser.fdt_list, list) { - debugfs_remove(ff->file); - list_del(&ff->list); - kfree(ff); - } - } - - return err; -} - static int __kho_abort(void) { int err; @@ -1116,8 +1057,9 @@ int kho_abort(void) return ret; kho_out.finalized = false; + kho_debugfs_cleanup(&kho_out.dbg); - return kho_out_update_debugfs_fdt(); + return 0; } static int __kho_finalize(void) @@ -1186,89 +1128,23 @@ int kho_finalize(void) kho_out.finalized = true; - return kho_out_update_debugfs_fdt(); -} - -static int kho_out_finalize_get(void *data, u64 *val) -{ - mutex_lock(&kho_out.lock); - *val = kho_out.finalized; - mutex_unlock(&kho_out.lock); - - return 0; -} - -static int kho_out_finalize_set(void *data, u64 _val) -{ - return (!!_val) ? kho_finalize() : kho_abort(); + return kho_debugfs_fdt_add(&kho_out.dbg, "fdt", + page_to_virt(kho_out.ser.fdt), true); } -DEFINE_DEBUGFS_ATTRIBUTE(fops_kho_out_finalize, kho_out_finalize_get, - kho_out_finalize_set, "%llu\n"); - -static int scratch_phys_show(struct seq_file *m, void *v) +bool kho_finalized(void) { - for (int i = 0; i < kho_scratch_cnt; i++) - seq_printf(m, "0x%llx\n", kho_scratch[i].addr); - - return 0; -} -DEFINE_SHOW_ATTRIBUTE(scratch_phys); - -static int scratch_len_show(struct seq_file *m, void *v) -{ - for (int i = 0; i < kho_scratch_cnt; i++) - seq_printf(m, "0x%llx\n", kho_scratch[i].size); - - return 0; -} -DEFINE_SHOW_ATTRIBUTE(scratch_len); - -static __init int kho_out_debugfs_init(void) -{ - struct dentry *dir, *f, *sub_fdt_dir; - - dir = debugfs_create_dir("out", debugfs_root); - if (IS_ERR(dir)) - return -ENOMEM; - - sub_fdt_dir = debugfs_create_dir("sub_fdts", dir); - if (IS_ERR(sub_fdt_dir)) - goto err_rmdir; - - f = debugfs_create_file("scratch_phys", 0400, dir, NULL, - &scratch_phys_fops); - if (IS_ERR(f)) - goto err_rmdir; - - f = debugfs_create_file("scratch_len", 0400, dir, NULL, - &scratch_len_fops); - if (IS_ERR(f)) - goto err_rmdir; - - f = debugfs_create_file("finalize", 0600, dir, NULL, - &fops_kho_out_finalize); - if (IS_ERR(f)) - goto err_rmdir; - - kho_out.dir = dir; - kho_out.ser.sub_fdt_dir = sub_fdt_dir; - return 0; - -err_rmdir: - debugfs_remove_recursive(dir); - return -ENOENT; + guard(mutex)(&kho_out.lock); + return kho_out.finalized; } struct kho_in { - struct dentry *dir; phys_addr_t fdt_phys; phys_addr_t scratch_phys; - struct list_head fdt_list; + struct kho_debugfs dbg; }; static struct kho_in kho_in = { - .fdt_list = LIST_HEAD_INIT(kho_in.fdt_list), }; static const void *kho_get_fdt(void) @@ -1332,56 +1208,6 @@ int kho_retrieve_subtree(const char *nam } EXPORT_SYMBOL_GPL(kho_retrieve_subtree); -/* Handling for debugfs/kho/in */ - -static __init int kho_in_debugfs_init(const void *fdt) -{ - struct dentry *sub_fdt_dir; - int err, child; - - kho_in.dir = debugfs_create_dir("in", debugfs_root); - if (IS_ERR(kho_in.dir)) - return PTR_ERR(kho_in.dir); - - sub_fdt_dir = debugfs_create_dir("sub_fdts", kho_in.dir); - if (IS_ERR(sub_fdt_dir)) { - err = PTR_ERR(sub_fdt_dir); - goto err_rmdir; - } - - err = kho_debugfs_fdt_add(&kho_in.fdt_list, kho_in.dir, "fdt", fdt); - if (err) - goto err_rmdir; - - fdt_for_each_subnode(child, fdt, 0) { - int len = 0; - const char *name = fdt_get_name(fdt, child, NULL); - const u64 *fdt_phys; - - fdt_phys = fdt_getprop(fdt, child, "fdt", &len); - if (!fdt_phys) - continue; - if (len != sizeof(*fdt_phys)) { - pr_warn("node `%s`'s prop `fdt` has invalid length: %d\n", - name, len); - continue; - } - err = kho_debugfs_fdt_add(&kho_in.fdt_list, sub_fdt_dir, name, - phys_to_virt(*fdt_phys)); - if (err) { - pr_warn("failed to add fdt `%s` to debugfs: %d\n", name, - err); - continue; - } - } - - return 0; - -err_rmdir: - debugfs_remove_recursive(kho_in.dir); - return err; -} - static __init int kho_init(void) { int err = 0; @@ -1396,27 +1222,16 @@ static __init int kho_init(void) goto err_free_scratch; } - debugfs_root = debugfs_create_dir("kho", NULL); - if (IS_ERR(debugfs_root)) { - err = -ENOENT; + err = kho_debugfs_init(); + if (err) goto err_free_fdt; - } - err = kho_out_debugfs_init(); + err = kho_out_debugfs_init(&kho_out.dbg); if (err) goto err_free_fdt; if (fdt) { - err = kho_in_debugfs_init(fdt); - /* - * Failure to create /sys/kernel/debug/kho/in does not prevent - * reviving state from KHO and setting up KHO for the next - * kexec. - */ - if (err) - pr_err("failed exposing handover FDT in debugfs: %d\n", - err); - + kho_in_debugfs_init(&kho_in.dbg, fdt); return 0; } diff --git a/kernel/kexec_handover_debug.c a/kernel/kexec_handover_debug.c new file mode 100644 --- /dev/null +++ a/kernel/kexec_handover_debug.c @@ -0,0 +1,213 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * kexec_handover.c - kexec handover metadata processing + * Copyright (C) 2023 Alexander Graf + * Copyright (C) 2025 Microsoft Corporation, Mike Rapoport + * Copyright (C) 2025 Google LLC, Changyuan Lyu + * Copyright (C) 2025 Google LLC, Pasha Tatashin + */ + +#define pr_fmt(fmt) "KHO: " fmt + +#include +#include +#include +#include +#include "kexec_handover_internal.h" + +static struct dentry *debugfs_root; + +struct fdt_debugfs { + struct list_head list; + struct debugfs_blob_wrapper wrapper; + struct dentry *file; +}; + +static int __kho_debugfs_fdt_add(struct list_head *list, struct dentry *dir, + const char *name, const void *fdt) +{ + struct fdt_debugfs *f; + struct dentry *file; + + f = kmalloc(sizeof(*f), GFP_KERNEL); + if (!f) + return -ENOMEM; + + f->wrapper.data = (void *)fdt; + f->wrapper.size = fdt_totalsize(fdt); + + file = debugfs_create_blob(name, 0400, dir, &f->wrapper); + if (IS_ERR(file)) { + kfree(f); + return PTR_ERR(file); + } + + f->file = file; + list_add(&f->list, list); + + return 0; +} + +int kho_debugfs_fdt_add(struct kho_debugfs *dbg, const char *name, + const void *fdt, bool root) +{ + struct dentry *dir; + + if (root) + dir = dbg->dir; + else + dir = dbg->sub_fdt_dir; + + return __kho_debugfs_fdt_add(&dbg->fdt_list, dir, name, fdt); +} + +void kho_debugfs_cleanup(struct kho_debugfs *dbg) +{ + struct fdt_debugfs *ff, *tmp; + + list_for_each_entry_safe(ff, tmp, &dbg->fdt_list, list) { + debugfs_remove(ff->file); + list_del(&ff->list); + kfree(ff); + } +} + +static int kho_out_finalize_get(void *data, u64 *val) +{ + *val = kho_finalized(); + + return 0; +} + +static int kho_out_finalize_set(void *data, u64 _val) +{ + return (!!_val) ? kho_finalize() : kho_abort(); +} + +DEFINE_DEBUGFS_ATTRIBUTE(kho_out_finalize_fops, kho_out_finalize_get, + kho_out_finalize_set, "%llu\n"); + +static int scratch_phys_show(struct seq_file *m, void *v) +{ + for (int i = 0; i < kho_scratch_cnt; i++) + seq_printf(m, "0x%llx\n", kho_scratch[i].addr); + + return 0; +} +DEFINE_SHOW_ATTRIBUTE(scratch_phys); + +static int scratch_len_show(struct seq_file *m, void *v) +{ + for (int i = 0; i < kho_scratch_cnt; i++) + seq_printf(m, "0x%llx\n", kho_scratch[i].size); + + return 0; +} +DEFINE_SHOW_ATTRIBUTE(scratch_len); + +__init void kho_in_debugfs_init(struct kho_debugfs *dbg, const void *fdt) +{ + struct dentry *dir, *sub_fdt_dir; + int err, child; + + INIT_LIST_HEAD(&dbg->fdt_list); + + dir = debugfs_create_dir("in", debugfs_root); + if (IS_ERR(dir)) { + err = PTR_ERR(dir); + goto err_out; + } + + sub_fdt_dir = debugfs_create_dir("sub_fdts", dir); + if (IS_ERR(sub_fdt_dir)) { + err = PTR_ERR(sub_fdt_dir); + goto err_rmdir; + } + + err = __kho_debugfs_fdt_add(&dbg->fdt_list, dir, "fdt", fdt); + if (err) + goto err_rmdir; + + fdt_for_each_subnode(child, fdt, 0) { + int len = 0; + const char *name = fdt_get_name(fdt, child, NULL); + const u64 *fdt_phys; + + fdt_phys = fdt_getprop(fdt, child, "fdt", &len); + if (!fdt_phys) + continue; + if (len != sizeof(*fdt_phys)) { + pr_warn("node %s prop fdt has invalid length: %d\n", + name, len); + continue; + } + err = __kho_debugfs_fdt_add(&dbg->fdt_list, sub_fdt_dir, name, + phys_to_virt(*fdt_phys)); + if (err) { + pr_warn("failed to add fdt %s to debugfs: %d\n", name, + err); + continue; + } + } + + dbg->dir = dir; + dbg->sub_fdt_dir = sub_fdt_dir; + + return; +err_rmdir: + debugfs_remove_recursive(dir); +err_out: + /* + * Failure to create /sys/kernel/debug/kho/in does not prevent + * reviving state from KHO and setting up KHO for the next + * kexec. + */ + if (err) + pr_err("failed exposing handover FDT in debugfs: %d\n", err); +} + +__init int kho_out_debugfs_init(struct kho_debugfs *dbg) +{ + struct dentry *dir, *f, *sub_fdt_dir; + + INIT_LIST_HEAD(&dbg->fdt_list); + + dir = debugfs_create_dir("out", debugfs_root); + if (IS_ERR(dir)) + return -ENOMEM; + + sub_fdt_dir = debugfs_create_dir("sub_fdts", dir); + if (IS_ERR(sub_fdt_dir)) + goto err_rmdir; + + f = debugfs_create_file("scratch_phys", 0400, dir, NULL, + &scratch_phys_fops); + if (IS_ERR(f)) + goto err_rmdir; + + f = debugfs_create_file("scratch_len", 0400, dir, NULL, + &scratch_len_fops); + if (IS_ERR(f)) + goto err_rmdir; + + f = debugfs_create_file("finalize", 0600, dir, NULL, + &kho_out_finalize_fops); + if (IS_ERR(f)) + goto err_rmdir; + + dbg->dir = dir; + dbg->sub_fdt_dir = sub_fdt_dir; + return 0; + +err_rmdir: + debugfs_remove_recursive(dir); + return -ENOENT; +} + +__init int kho_debugfs_init(void) +{ + debugfs_root = debugfs_create_dir("kho", NULL); + if (IS_ERR(debugfs_root)) + return -ENOENT; + return 0; +} diff --git a/kernel/kexec_handover_internal.h a/kernel/kexec_handover_internal.h new file mode 100644 --- /dev/null +++ a/kernel/kexec_handover_internal.h @@ -0,0 +1,44 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef LINUX_KEXEC_HANDOVER_INTERNAL_H +#define LINUX_KEXEC_HANDOVER_INTERNAL_H + +#include +#include +#include + +#ifdef CONFIG_KEXEC_HANDOVER_DEBUGFS +#include + +struct kho_debugfs { + struct dentry *dir; + struct dentry *sub_fdt_dir; + struct list_head fdt_list; +}; + +#else +struct kho_debugfs {}; +#endif + +extern struct kho_scratch *kho_scratch; +extern unsigned int kho_scratch_cnt; + +bool kho_finalized(void); + +#ifdef CONFIG_KEXEC_HANDOVER_DEBUGFS +int kho_debugfs_init(void); +void kho_in_debugfs_init(struct kho_debugfs *dbg, const void *fdt); +int kho_out_debugfs_init(struct kho_debugfs *dbg); +int kho_debugfs_fdt_add(struct kho_debugfs *dbg, const char *name, + const void *fdt, bool root); +void kho_debugfs_cleanup(struct kho_debugfs *dbg); +#else +static inline int kho_debugfs_init(void) { return 0; } +static inline void kho_in_debugfs_init(struct kho_debugfs *dbg, + const void *fdt) { } +static inline int kho_out_debugfs_init(struct kho_debugfs *dbg) { return 0; } +static inline int kho_debugfs_fdt_add(struct kho_debugfs *dbg, const char *name, + const void *fdt, bool root) { return 0; } +static inline void kho_debugfs_cleanup(struct kho_debugfs *dbg) {} +#endif /* CONFIG_KEXEC_HANDOVER_DEBUGFS */ + +#endif /* LINUX_KEXEC_HANDOVER_INTERNAL_H */ --- a/kernel/Makefile~kho-make-debugfs-interface-optional +++ a/kernel/Makefile @@ -83,6 +83,7 @@ obj-$(CONFIG_KEXEC) += kexec.o obj-$(CONFIG_KEXEC_FILE) += kexec_file.o obj-$(CONFIG_KEXEC_ELF) += kexec_elf.o obj-$(CONFIG_KEXEC_HANDOVER) += kexec_handover.o +obj-$(CONFIG_KEXEC_HANDOVER_DEBUGFS) += kexec_handover_debug.o obj-$(CONFIG_BACKTRACE_SELF_TEST) += backtracetest.o obj-$(CONFIG_COMPAT) += compat.o obj-$(CONFIG_CGROUPS) += cgroup/ --- a/MAINTAINERS~kho-make-debugfs-interface-optional +++ a/MAINTAINERS @@ -13754,13 +13754,14 @@ KEXEC HANDOVER (KHO) M: Alexander Graf M: Mike Rapoport M: Changyuan Lyu +M: Pasha Tatashin L: kexec@lists.infradead.org L: linux-mm@kvack.org S: Maintained F: Documentation/admin-guide/mm/kho.rst F: Documentation/core-api/kho/* F: include/linux/kexec_handover.h -F: kernel/kexec_handover.c +F: kernel/kexec_handover* F: tools/testing/selftests/kho/ KEYS-ENCRYPTED --- a/tools/testing/selftests/kho/vmtest.sh~kho-make-debugfs-interface-optional +++ a/tools/testing/selftests/kho/vmtest.sh @@ -59,6 +59,7 @@ function build_kernel() { tee "$kconfig" > "$kho_config" <