From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B7738CAC5BB for ; Mon, 29 Sep 2025 01:03:39 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id CB1028E000A; Sun, 28 Sep 2025 21:03:37 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id BEC318E0001; Sun, 28 Sep 2025 21:03:37 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9F1288E000A; Sun, 28 Sep 2025 21:03:37 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 7E4048E0001 for ; Sun, 28 Sep 2025 21:03:37 -0400 (EDT) Received: from smtpin09.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 38920118DB9 for ; Mon, 29 Sep 2025 01:03:37 +0000 (UTC) X-FDA: 83940490074.09.22BC2CC Received: from mail-qk1-f175.google.com (mail-qk1-f175.google.com [209.85.222.175]) by imf24.hostedemail.com (Postfix) with ESMTP id 69C4818000C for ; Mon, 29 Sep 2025 01:03:35 +0000 (UTC) Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=soleen.com header.s=google header.b=gWuWX1se; dmarc=pass (policy=reject) header.from=soleen.com; spf=pass (imf24.hostedemail.com: domain of pasha.tatashin@soleen.com designates 209.85.222.175 as permitted sender) smtp.mailfrom=pasha.tatashin@soleen.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1759107815; a=rsa-sha256; cv=none; b=X/bEu5eIvfvfNgkUjE78SE3oJT+i7Dex5x+nWHAvFoZrPddIPc3f1Izqx1f7C4wlmZ4ZD3 Cde6yuQoaglhNcSxahEMsqxULvApixzHAmkifqWNDVK9qTGP2vUJilOW5I9dUVnXd806XJ m5HhryS0yeFjpNSJBwNd1MxL5EZhbjE= ARC-Authentication-Results: i=1; imf24.hostedemail.com; dkim=pass header.d=soleen.com header.s=google header.b=gWuWX1se; dmarc=pass (policy=reject) header.from=soleen.com; spf=pass (imf24.hostedemail.com: domain of pasha.tatashin@soleen.com designates 209.85.222.175 as permitted sender) smtp.mailfrom=pasha.tatashin@soleen.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1759107815; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:mime-version:mime-version:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=M+0a641RVp4eNXltm9Frq8R4NOKxAZQzQ19sOBX9Om4=; b=fKD+Ib4fmboCSka0vGG8Z73DjqmzhfCggcQIfm8HrMnpD1wKCMwC3VCCCj3egl7Xu8KmKh V52B10ti8uXVg+4bm4u8bHC6Mpmmv43jFliV6rxSi20HCNCAE3lQsl9aXQVlr+/fsnCg0C hYvCno1Wyi5DmFAmAiTMYHf7/3fAmUs= Received: by mail-qk1-f175.google.com with SMTP id af79cd13be357-85e76e886a0so273371685a.1 for ; Sun, 28 Sep 2025 18:03:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=soleen.com; s=google; t=1759107814; x=1759712614; darn=kvack.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:to:from:from:to:cc:subject:date:message-id :reply-to; bh=M+0a641RVp4eNXltm9Frq8R4NOKxAZQzQ19sOBX9Om4=; b=gWuWX1se/0YwM5Jn/CgecM5+w8nLHFnbX97OmYFRTNy9pDvIuz1naRAHAHEc3u79kW ee0FPJg/RFrH1aENVslUya6zGCpFwwSPu6h8hJbKum+IVQob15ew7xL2lGsL/o+MxDEo Bmyz6iLOXre1v98zkaXRNdMKNd9sFdcgjgO+em2ifSaqCssBZUq6aqA/y1x6HryoEN3R wyFZvqUETZX+t1ZE8T2+rorEmdsgN8HMyloppayrJP5I9vZ3yYUsL9TB4IFrzAho2no7 dDCnISN0qr7kCNe+duhzGg0aVgcckLocy0ztAyzwVbRtnbDmXyTiJMngiSKzSnuXwyLQ bN/g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1759107814; x=1759712614; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=M+0a641RVp4eNXltm9Frq8R4NOKxAZQzQ19sOBX9Om4=; b=S0u8Y4VflTBCEp9Bxjq60Es14sg4lKxJWN131p18CgK8ASUyce8ysNP9PZcdJ9DJLX rfXXr5dT8wBWVVtlSOqu3in4+sHC3DRCFslUWjoFUeqER1sEdBgQSobSivkwhX70OATw 95N6Qa4rW2GDIeAqaTo6H5WzrvS1tq7F4s7VHp6GjHjf59t1VkmnIM5bPDGydZU3nCzt lGyTy1bRRsepJlgQE3ge1WKWeGUyV5MwMWKRVyy3QlgfGRO3uCpoP1lozFNHOEzsl4oM u9TCTnWqjdQ0gpoUWZWLvoNEzzob1I5g5UbKMdPOz3luhAP8LCEnI8N4KSzsfSzackwo mGrQ== X-Forwarded-Encrypted: i=1; AJvYcCUc5PwmlvQGpzls5Awx7YSYOYSadOfg7TK3vODgWjwx0jHVAKJaABaenaCZ5VWUT4mnP/ciDuYUhQ==@kvack.org X-Gm-Message-State: AOJu0YzIwSvn0HJz2ixwGX0HBd3tOJuUbUERzhqggTmo2iZXCsn/E2Lz X/IWtUamuMQORzTmSl/DVYjJSjbVPq562MEhLvDnH3rP3jceWPB3oMDlJOsLPKu9f+g= X-Gm-Gg: ASbGncsVNMm1fQCkPq7SjPJbCIJ8ihLUJQSjZNZi+mFUhBSOdpzvrI+uClg17oeSSFu 0sPON4vG/tRlXAw5DHXYtFEFfLvLzzT1iW9fIAGNk7XJrg1FjdoVqIu+gjfOgqPHrnSZAjjXfkN Qx8WdCKYpvI3hIpf0VJmvRaBlN19RNnuH0ljx4Tq1QKFG8/YN0JjOi4PFRcJaYVtfJDvmQWXQ41 V30CMAfkgwoWcyfiguipfxWY7b925oAi1s5Piv+UBEKMcdfkoZxZAt/aEHbAX8XmErPhf3t/pm6 qUUKUOK41Dy9fIdm0AKM9qrTuc56EiE8ZiWg+lYOaU8j/VX/qL4sl8d0998vu0+lexKMyYJgSEV NXduR8XVuKLVa5Mer6/WR7yHDhnur7OhMg82Cz1DOBsx+VMmEUdNI/snPaxjE0amvog+asnKdUI MCpBRrdR4= X-Google-Smtp-Source: AGHT+IGonW1CRHUUsXyfbJh6ZoXbzRjlubAVAKY6OPaG8ochgaHRZVLV4raeX9y82h2VGUt1hBc7Vw== X-Received: by 2002:a05:620a:25d4:b0:84c:e9:f9d7 with SMTP id af79cd13be357-85ae7fb3278mr1782998185a.62.1759107814346; Sun, 28 Sep 2025 18:03:34 -0700 (PDT) Received: from soleen.c.googlers.com.com (53.47.86.34.bc.googleusercontent.com. [34.86.47.53]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-4db0c0fbe63sm64561521cf.23.2025.09.28.18.03.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 28 Sep 2025 18:03:33 -0700 (PDT) From: Pasha Tatashin To: pratyush@kernel.org, jasonmiu@google.com, graf@amazon.com, changyuanl@google.com, pasha.tatashin@soleen.com, rppt@kernel.org, dmatlack@google.com, rientjes@google.com, corbet@lwn.net, rdunlap@infradead.org, ilpo.jarvinen@linux.intel.com, kanie@linux.alibaba.com, ojeda@kernel.org, aliceryhl@google.com, masahiroy@kernel.org, akpm@linux-foundation.org, tj@kernel.org, yoann.congal@smile.fr, mmaurer@google.com, roman.gushchin@linux.dev, chenridong@huawei.com, axboe@kernel.dk, mark.rutland@arm.com, jannh@google.com, vincent.guittot@linaro.org, hannes@cmpxchg.org, dan.j.williams@intel.com, david@redhat.com, joel.granados@kernel.org, rostedt@goodmis.org, anna.schumaker@oracle.com, song@kernel.org, zhangguopeng@kylinos.cn, linux@weissschuh.net, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, gregkh@linuxfoundation.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, rafael@kernel.org, dakr@kernel.org, bartosz.golaszewski@linaro.org, cw00.choi@samsung.com, myungjoo.ham@samsung.com, yesanishhere@gmail.com, Jonathan.Cameron@huawei.com, quic_zijuhu@quicinc.com, aleksander.lobakin@intel.com, ira.weiny@intel.com, andriy.shevchenko@linux.intel.com, leon@kernel.org, lukas@wunner.de, bhelgaas@google.com, wagi@kernel.org, djeffery@redhat.com, stuart.w.hayes@gmail.com, ptyadav@amazon.de, lennart@poettering.net, brauner@kernel.org, linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org, saeedm@nvidia.com, ajayachandra@nvidia.com, jgg@nvidia.com, parav@nvidia.com, leonro@nvidia.com, witu@nvidia.com, hughd@google.com, skhawaja@google.com, chrisl@kernel.org, steven.sistare@oracle.com Subject: [PATCH v4 02/30] kho: make debugfs interface optional Date: Mon, 29 Sep 2025 01:02:53 +0000 Message-ID: <20250929010321.3462457-3-pasha.tatashin@soleen.com> X-Mailer: git-send-email 2.51.0.536.g15c5d4f767-goog In-Reply-To: <20250929010321.3462457-1-pasha.tatashin@soleen.com> References: <20250929010321.3462457-1-pasha.tatashin@soleen.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 69C4818000C X-Stat-Signature: 8e5wtm187dzf9wbt1idafpgtqb4r89i9 X-Rspam-User: X-HE-Tag: 1759107815-423021 X-HE-Meta: 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 qrJN5nH5 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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_DEBUG 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. Co-developed-by: Mike Rapoport (Microsoft) Signed-off-by: Mike Rapoport (Microsoft) Signed-off-by: Pasha Tatashin --- MAINTAINERS | 3 +- kernel/Kconfig.kexec | 10 ++ kernel/Makefile | 1 + kernel/kexec_handover.c | 255 +++++-------------------------- kernel/kexec_handover_debug.c | 218 ++++++++++++++++++++++++++ kernel/kexec_handover_internal.h | 44 ++++++ 6 files changed, 311 insertions(+), 220 deletions(-) create mode 100644 kernel/kexec_handover_debug.c create mode 100644 kernel/kexec_handover_internal.h diff --git a/MAINTAINERS b/MAINTAINERS index 156fa8eefa69..a6cbcc7fb396 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -13759,13 +13759,14 @@ 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 diff --git a/kernel/Kconfig.kexec b/kernel/Kconfig.kexec index 422270d64820..e68156d8c72b 100644 --- a/kernel/Kconfig.kexec +++ b/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_DEBUG + bool "kexec handover debug 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 diff --git a/kernel/Makefile b/kernel/Makefile index df3dd8291bb6..9fe722305c9b 100644 --- a/kernel/Makefile +++ b/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-$(CONFIG_KEXEC_HANDOVER_DEBUG) += kexec_handover_debug.o obj-$(CONFIG_BACKTRACE_SELF_TEST) += backtracetest.o obj-$(CONFIG_COMPAT) += compat.o obj-$(CONFIG_CGROUPS) += cgroup/ diff --git a/kernel/kexec_handover.c b/kernel/kexec_handover.c index 0ba5a2dbae28..f0f6c6b8ad83 100644 --- a/kernel/kexec_handover.c +++ b/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; @@ -465,8 +463,8 @@ static void __init kho_mem_deserialize(const void *fdt) * 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 @@ -662,36 +660,24 @@ static void __init kho_reserve_scratch(void) kho_enable = false; } -struct fdt_debugfs { - struct list_head list; - struct debugfs_blob_wrapper wrapper; - struct dentry *file; +struct kho_out { + struct blocking_notifier_head chain_head; + struct mutex lock; /* protects KHO FDT finalization */ + struct kho_serialization ser; + bool finalized; + struct kho_debugfs dbg; }; -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; -} +static struct kho_out kho_out = { + .chain_head = BLOCKING_NOTIFIER_INIT(kho_out.chain_head), + .lock = __MUTEX_INITIALIZER(kho_out.lock), + .ser = { + .track = { + .orders = XARRAY_INIT(kho_out.ser.track.orders, 0), + }, + }, + .finalized = false, +}; /** * kho_add_subtree - record the physical address of a sub FDT in KHO root tree. @@ -704,7 +690,8 @@ static int kho_debugfs_fdt_add(struct list_head *list, struct dentry *dir, * 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_DEBUG * * Return: 0 on success, error code on failure */ @@ -721,7 +708,7 @@ int kho_add_subtree(struct kho_serialization *ser, const char *name, void *fdt) 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 +1031,6 @@ void *kho_restore_vmalloc(const struct kho_vmalloc *preservation) } 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; @@ -1119,7 +1083,8 @@ int kho_abort(void) goto unlock; kho_out.finalized = false; - ret = kho_out_update_debugfs_fdt(); + + kho_debugfs_cleanup(&kho_out.dbg); unlock: mutex_unlock(&kho_out.lock); @@ -1169,7 +1134,7 @@ static int __kho_finalize(void) abort: if (err) { pr_err("Failed to convert KHO state tree: %d\n", err); - kho_abort(); + __kho_abort(); } return err; @@ -1194,119 +1159,32 @@ int kho_finalize(void) goto unlock; kho_out.finalized = true; - ret = kho_out_update_debugfs_fdt(); + ret = kho_debugfs_fdt_add(&kho_out.dbg, "fdt", + page_to_virt(kho_out.ser.fdt), true); unlock: mutex_unlock(&kho_out.lock); return ret; } -static int kho_out_finalize_get(void *data, u64 *val) +bool kho_finalized(void) { - 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) -{ - int ret = 0; - bool val = !!_val; + bool ret; mutex_lock(&kho_out.lock); - - if (val == kho_out.finalized) { - if (kho_out.finalized) - ret = -EEXIST; - else - ret = -ENOENT; - goto unlock; - } - - if (val) - ret = kho_finalize(); - else - ret = kho_abort(); - - if (ret) - goto unlock; - - kho_out.finalized = val; - ret = kho_out_update_debugfs_fdt(); - -unlock: + ret = kho_out.finalized; mutex_unlock(&kho_out.lock); - return ret; -} - -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) -{ - 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; + return ret; } 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) @@ -1370,56 +1248,6 @@ int kho_retrieve_subtree(const char *name, phys_addr_t *phys) } 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; @@ -1434,27 +1262,16 @@ 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 b/kernel/kexec_handover_debug.c new file mode 100644 index 000000000000..b88d138a97be --- /dev/null +++ b/kernel/kexec_handover_debug.c @@ -0,0 +1,218 @@ +// 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) +{ + bool val = !!_val; + + if (val) + return kho_finalize(); + + return 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 b/kernel/kexec_handover_internal.h new file mode 100644 index 000000000000..f6f172ddcae4 --- /dev/null +++ b/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_DEBUG +#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_DEBUG +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_DEBUG */ + +#endif /* LINUX_KEXEC_HANDOVER_INTERNAL_H */ -- 2.51.0.536.g15c5d4f767-goog