From patchwork Fri Jan 5 10:33:00 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Baoquan He X-Patchwork-Id: 13511928 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 23BF028E27 for ; Fri, 5 Jan 2024 10:33:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Yx2bDYc7" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1704450800; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=2vTzdCgrBtcA7j5NHuC5/JJylMuPL+B3tt+xvWm2XXw=; b=Yx2bDYc7uqQpQw7N6xzFw2DqrPE27O9Hu/XQzTvoaI9Y1OSfmEqt+FVhoN7JT0BEQ5eTI0 633UML6sLm1ekXCHbFmmqAmF17n0Xnxx7po29gGr/Ka/tXlEaDLzvjIOsp1veV9m4VYgrj MG7+1rs4IfT3ZfYosiXP6RBDLpTnJYE= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-445-qIBgTU_rPeSjkbO0f1WUPA-1; Fri, 05 Jan 2024 05:33:17 -0500 X-MC-Unique: qIBgTU_rPeSjkbO0f1WUPA-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 4AF46833945; Fri, 5 Jan 2024 10:33:16 +0000 (UTC) Received: from MiWiFi-R3L-srv.redhat.com (unknown [10.72.116.129]) by smtp.corp.redhat.com (Postfix) with ESMTP id 78119492BC6; Fri, 5 Jan 2024 10:33:10 +0000 (UTC) From: Baoquan He To: linux-kernel@vger.kernel.org Cc: akpm@linux-foundation.org, kexec@lists.infradead.org, hbathini@linux.ibm.com, arnd@arndb.de, ignat@cloudflare.com, eric_devolder@yahoo.com, viro@zeniv.linux.org.uk, ebiederm@xmission.com, x86@kernel.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, Baoquan He Subject: [PATCH 0/5] crash: clean up kdump related config items Date: Fri, 5 Jan 2024 18:33:00 +0800 Message-ID: <20240105103305.557273-1-bhe@redhat.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.9 Motivation: ============= Previously, LKP reported a building error. When investigating, it can't be resolved reasonablly with the present messy kdump config items. https://lore.kernel.org/oe-kbuild-all/202312182200.Ka7MzifQ-lkp@intel.com/ The kdump (crash dumping) related config items could causes confusions: Firstly, --- CRASH_CORE enables codes including - crashkernel reservation parsing; - elfcorehdr updating; - vmcoreinfo saving; - crash hotplug handling; Now fadump of powerpc, kcore dynamic debugging and kdump all selects CRASH_CORE, while fadump - fadump needs crashkernel parsing, vmcoreinfo and accessing global variable 'elfcorehdr_addr'; - kcore needs saved vmcoreinfo; - kdump needs all of the current kernel/crash_core.c. So only enabling PROC_CORE or FA_DUMP will enable CRASH_CORE will confuse people that we enable the core code of kdump. Actually it's not. Secondly, --- It's not reasonable to allow KEXEC_CORE select CRASH_CORE. Because KEXEC_CORE enables codes which allocate control pages, copy kexec/kdump segments, and prepare for switching. These codes are shared by both kexec_load and kexec_file_load, and by both kexec reboot and kdump. We could want kexec reboot, but disable kdump. In that case, CRASH_CORE should not be selected. Thirdly, --- It's not reasonable to allow CRASH_DUMP select KEXEC_CORE. That could make KEXEC_CORE, CRASH_DUMP are enabled independently from KEXEC or KEXEC_FILE. However, w/o KEXEC or KEXEC_FILE, the KEXEC_CORE code built in doesn't make any sense because no kernel loading or switching will happen to utilize the KEXEC_CORE code. Changes: =========== 1, split CRASH_CORE codes into three parts: 1. move the elfcorehdr upating code and crash hotplug handling code into kernel/kexec_core.c. Both KEXEC and KEXEC_FILE will use them. 2. split crashkernel reservation code out into kernel/crash_reserve.c, add CRASH_RESERVE to control its enabling; 3. rename the left kernel/crash_core.c to kernel/vmcore_info.c since only vmcoreinfo is saved in the file, and add VMCORE_INFO to control its enabling; 2, rename the current kernel/crash_dump.c to kernel/elfcorehdr.c because it only defines elfcorehdr_addr and function parse_elfcorehdr() in the file. And build it in when VMCORE_INFO is enabled. Achievement: =========== With above changes, I can rearrange the config items as below (the right item depends on or is selected by the left item): PROC_KCORE -----------> VMCORE_INFO |----------> VMCORE_INFO FA_DUMP----| |----------> CRASH_RESERVE ---->VMCORE_INFO / |---->CRASH_RESERVE KEXEC --| /| |--> KEXEC_CORE--> CRASH_DUMP-->/-|---->PROC_VMCORE KEXEC_FILE --| \ | \---->CRASH_HOTPLUG KEXEC --| |--> KEXEC_CORE (for kexec reboot only) KEXEC_FILE --| Baoquan He (5): kexec_core: move kdump related codes from crash_core.c to kexec_core.c kexec: split crashkernel reservation code out from crash_core.c crash: rename crash_core to vmcore_info crash: remove dependency of FA_DUMP on CRASH_DUMP crash: clean up CRASH_DUMP arch/arm64/Kconfig | 2 +- .../asm/{crash_core.h => crash_reserve.h} | 4 +- arch/arm64/kernel/Makefile | 2 +- .../kernel/{crash_core.c => vmcore_info.c} | 2 +- arch/powerpc/Kconfig | 4 +- arch/powerpc/kernel/setup-common.c | 2 +- arch/powerpc/mm/nohash/kaslr_booke.c | 4 +- arch/powerpc/platforms/powernv/opal-core.c | 2 +- arch/riscv/Kconfig | 2 +- .../asm/{crash_core.h => crash_reserve.h} | 4 +- arch/riscv/kernel/Makefile | 2 +- .../kernel/{crash_core.c => vmcore_info.c} | 2 +- arch/x86/Kconfig | 2 +- .../asm/{crash_core.h => crash_reserve.h} | 6 +- arch/x86/kernel/Makefile | 2 +- .../{crash_core_32.c => vmcore_info_32.c} | 2 +- .../{crash_core_64.c => vmcore_info_64.c} | 2 +- drivers/firmware/qemu_fw_cfg.c | 14 +- fs/proc/Kconfig | 2 +- fs/proc/kcore.c | 2 +- include/linux/buildid.h | 2 +- include/linux/crash_reserve.h | 48 + include/linux/kexec.h | 27 +- include/linux/{crash_core.h => vmcore_info.h} | 78 +- kernel/Kconfig.kexec | 12 +- kernel/Makefile | 4 +- kernel/crash_core.c | 1065 ----------------- kernel/crash_reserve.c | 453 +++++++ kernel/{crash_dump.c => elfcorehdr.c} | 0 kernel/kexec_core.c | 408 +++++++ kernel/kexec_internal.h | 2 + kernel/ksysfs.c | 6 +- kernel/printk/printk.c | 4 +- kernel/vmcore_info.c | 233 ++++ lib/buildid.c | 2 +- 35 files changed, 1222 insertions(+), 1186 deletions(-) rename arch/arm64/include/asm/{crash_core.h => crash_reserve.h} (81%) rename arch/arm64/kernel/{crash_core.c => vmcore_info.c} (97%) rename arch/riscv/include/asm/{crash_core.h => crash_reserve.h} (78%) rename arch/riscv/kernel/{crash_core.c => vmcore_info.c} (96%) rename arch/x86/include/asm/{crash_core.h => crash_reserve.h} (92%) rename arch/x86/kernel/{crash_core_32.c => vmcore_info_32.c} (90%) rename arch/x86/kernel/{crash_core_64.c => vmcore_info_64.c} (94%) create mode 100644 include/linux/crash_reserve.h rename include/linux/{crash_core.h => vmcore_info.h} (59%) delete mode 100644 kernel/crash_core.c create mode 100644 kernel/crash_reserve.c rename kernel/{crash_dump.c => elfcorehdr.c} (100%) create mode 100644 kernel/vmcore_info.c