From nobody Fri Jun 19 17:59:41 2026 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 263B7C433F5 for ; Thu, 31 Mar 2022 08:24:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232723AbiCaI0g (ORCPT ); Thu, 31 Mar 2022 04:26:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53832 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232758AbiCaI03 (ORCPT ); Thu, 31 Mar 2022 04:26:29 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C2C7D57494; Thu, 31 Mar 2022 01:24:37 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 77CD6B81FE2; Thu, 31 Mar 2022 08:24:36 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 220F1C340ED; Thu, 31 Mar 2022 08:24:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1648715075; bh=jLjZOnXI/ACGnxXl3tZNcFkD6L1cKyv9i4IjbKr7Ueg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=QwVpjamY9mYUgvW0d/8/WpYGLGvI60EkqDIwxeT2m3TRr3GjGx1sQi6wTA4t5+rbA J6pOEBjndq2T5Fic/nNNpNyF2ccxR9dHSuWM5e7igzVA9mI2PRk9yx8UnekVpOrsjY lVZMW3CGc2bDTBoH70wxSi+EgBt79pkkUYDd52SpOVQEViUryfmkI/O+dteVKD/kHs r44Fw6Ncj07p3SplNFNPciMQs2EluxF9BZI9dHzZrxAYrWxYmLuU8kZ474SKoGGLi/ EJkJ963ORnLI10dOZBdPWoziSkdE3gyzYSGzgg66IJOyOHSoMHmIdAf3nMzDNn20yy fAaCC0fu3Wuhw== From: Masami Hiramatsu To: Steven Rostedt Cc: Masami Hiramatsu , Padmanabha Srinivasaiah , LKML , Jonathan Corbet , linux-doc@vger.kernel.org, Randy Dunlap , Nick Desaulniers , Sami Tolvanen , Nathan Chancellor , llvm@lists.linux.dev, Masahiro Yamada , Linux Kbuild mailing list Subject: [PATCH v7 1/4] bootconfig: Make the bootconfig.o as a normal object file Date: Thu, 31 Mar 2022 17:24:29 +0900 Message-Id: <164871506921.178991.16611183818516468043.stgit@devnote2> X-Mailer: git-send-email 2.25.1 In-Reply-To: <164871505771.178991.7870442736805590948.stgit@devnote2> References: <164871505771.178991.7870442736805590948.stgit@devnote2> User-Agent: StGit/0.19 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Since the APIs defined in the bootconfig.o are not individually used, it is meaningless to build it as library by lib-y. Use obj-y for that. Reported-by: Masahiro Yamada Signed-off-by: Masami Hiramatsu --- Changes in v6: - Newly added. --- lib/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/lib/Makefile b/lib/Makefile index 6b9ffc1bd1ee..08053df16c7c 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -279,7 +279,7 @@ $(foreach file, $(libfdt_files), \ $(eval CFLAGS_$(file) =3D -I $(srctree)/scripts/dtc/libfdt)) lib-$(CONFIG_LIBFDT) +=3D $(libfdt_files) =20 -lib-$(CONFIG_BOOT_CONFIG) +=3D bootconfig.o +obj-$(CONFIG_BOOT_CONFIG) +=3D bootconfig.o =20 obj-$(CONFIG_RBTREE_TEST) +=3D rbtree_test.o obj-$(CONFIG_INTERVAL_TREE_TEST) +=3D interval_tree_test.o From nobody Fri Jun 19 17:59:41 2026 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CFE77C433FE for ; Thu, 31 Mar 2022 08:24:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232746AbiCaI0j (ORCPT ); Thu, 31 Mar 2022 04:26:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55184 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232719AbiCaI0g (ORCPT ); Thu, 31 Mar 2022 04:26:36 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0CD313E5EB; Thu, 31 Mar 2022 01:24:49 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id B5060B81FBA; Thu, 31 Mar 2022 08:24:47 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 61CDEC340ED; Thu, 31 Mar 2022 08:24:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1648715086; bh=/pcY0qB26eKeKCiib1+H0TY1vZCA9lmqTBCYWM/MIgg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ogLXPlhY4XW7CMerWzh0rUwxDEgncjsl1QInpH9dkPtmDBufm47Kige5mh61RDZld Lbv2VhtKem5ER3iPzbZzOIS5Tbwie8Ju5Z4DGoD35zo+rzOZoDKVJbjA8FO3qcuSfT SvOk1uG5qQ6t3Mv8bnhr74lTqYP3J7vzI1Lelzm409fgwPqmeKac7VwG7zHIxNoZ6r XCXJ8cZTRFuHjbC3ttsma5cIgcG8kJ/EKLHQFUy3k7/P+aFQkt1Vq/p8dZX07r1GGb k1yk1upH+2D/4/LRQVlWGRr12EukHcFiIUnzbgrUVEE0yw94jNL20UgAk6l4zZItFe gKzg62ilLbsig== From: Masami Hiramatsu To: Steven Rostedt Cc: Masami Hiramatsu , Padmanabha Srinivasaiah , LKML , Jonathan Corbet , linux-doc@vger.kernel.org, Randy Dunlap , Nick Desaulniers , Sami Tolvanen , Nathan Chancellor , llvm@lists.linux.dev, Masahiro Yamada , Linux Kbuild mailing list Subject: [PATCH v7 2/4] bootconfig: Check the checksum before removing the bootconfig from initrd Date: Thu, 31 Mar 2022 17:24:40 +0900 Message-Id: <164871508057.178991.1275961945357225120.stgit@devnote2> X-Mailer: git-send-email 2.25.1 In-Reply-To: <164871505771.178991.7870442736805590948.stgit@devnote2> References: <164871505771.178991.7870442736805590948.stgit@devnote2> User-Agent: StGit/0.19 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Check the bootconfig's checksum before removing the bootcinfig data from initrd to avoid modifying initrd by mistake. This will also simplifies the get_boot_config_from_initrd() interface. Signed-off-by: Masami Hiramatsu --- init/main.c | 22 ++++++++++------------ 1 file changed, 10 insertions(+), 12 deletions(-) diff --git a/init/main.c b/init/main.c index 98182c3c2c4b..266d61bc67b0 100644 --- a/init/main.c +++ b/init/main.c @@ -266,7 +266,7 @@ static int __init loglevel(char *str) early_param("loglevel", loglevel); =20 #ifdef CONFIG_BLK_DEV_INITRD -static void * __init get_boot_config_from_initrd(u32 *_size, u32 *_csum) +static void * __init get_boot_config_from_initrd(u32 *_size) { u32 size, csum; char *data; @@ -300,17 +300,20 @@ static void * __init get_boot_config_from_initrd(u32 = *_size, u32 *_csum) return NULL; } =20 + if (xbc_calc_checksum(data, size) !=3D csum) { + pr_err("bootconfig checksum failed\n"); + return NULL; + } + /* Remove bootconfig from initramfs/initrd */ initrd_end =3D (unsigned long)data; if (_size) *_size =3D size; - if (_csum) - *_csum =3D csum; =20 return data; } #else -static void * __init get_boot_config_from_initrd(u32 *_size, u32 *_csum) +static void * __init get_boot_config_from_initrd(u32 *_size) { return NULL; } @@ -409,12 +412,12 @@ static void __init setup_boot_config(void) static char tmp_cmdline[COMMAND_LINE_SIZE] __initdata; const char *msg; int pos; - u32 size, csum; + u32 size; char *data, *err; int ret; =20 /* Cut out the bootconfig data even if we have no bootconfig option */ - data =3D get_boot_config_from_initrd(&size, &csum); + data =3D get_boot_config_from_initrd(&size); =20 strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE); err =3D parse_args("bootconfig", tmp_cmdline, NULL, 0, 0, 0, NULL, @@ -438,11 +441,6 @@ static void __init setup_boot_config(void) return; } =20 - if (xbc_calc_checksum(data, size) !=3D csum) { - pr_err("bootconfig checksum failed\n"); - return; - } - ret =3D xbc_init(data, size, &msg, &pos); if (ret < 0) { if (pos < 0) @@ -471,7 +469,7 @@ static void __init exit_boot_config(void) static void __init setup_boot_config(void) { /* Remove bootconfig data from initrd */ - get_boot_config_from_initrd(NULL, NULL); + get_boot_config_from_initrd(NULL); } =20 static int __init warn_bootconfig(char *str) From nobody Fri Jun 19 17:59:41 2026 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4825AC433F5 for ; Thu, 31 Mar 2022 08:25:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232790AbiCaI1F (ORCPT ); Thu, 31 Mar 2022 04:27:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56020 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232760AbiCaI0q (ORCPT ); Thu, 31 Mar 2022 04:26:46 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2EBE0C6EFE; Thu, 31 Mar 2022 01:24:59 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id BEC2A616D3; Thu, 31 Mar 2022 08:24:58 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3E1A4C340ED; Thu, 31 Mar 2022 08:24:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1648715098; bh=Tw4EwvZXZvAbB7rmJ6FatvNo4a/BuwctLIn7ma+Ckb0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LmjtF1FW0X+GP/mNLMYJ2eXQTe8lj4CB9CYCVuzhufiMMW1iNLxBfdJEEGbXBZvWh IVMp+x9oTZzbB2ztXnC9EvEjPnVndNiLWXR58rEXgQ4FlpCeLZ6gvSWGClKAQNpb1j Ncb1NVRlqh/B6dnvlNmWMRn27FCwPUgwnf0Eikes1aS1g941UyR/hHbhIwW6mtizDe RJVL7fYJhi0m96waLtHQqrWnsGYRGDNoVg08DtdXSXYaW4ouhD+0FGYNvCdaaYbCDE 6hZ7GSZ7PT8tJfHueXbX7Z1ViPWUPuHiZuPFLS5cPCDvE1Zx1jLNXzfywxI1AGwvg1 yQgfcsybWCYTA== From: Masami Hiramatsu To: Steven Rostedt Cc: Masami Hiramatsu , Padmanabha Srinivasaiah , LKML , Jonathan Corbet , linux-doc@vger.kernel.org, Randy Dunlap , Nick Desaulniers , Sami Tolvanen , Nathan Chancellor , llvm@lists.linux.dev, Masahiro Yamada , Linux Kbuild mailing list Subject: [PATCH v7 3/4] bootconfig: Support embedding a bootconfig file in kernel Date: Thu, 31 Mar 2022 17:24:51 +0900 Message-Id: <164871509158.178991.12705786877340857725.stgit@devnote2> X-Mailer: git-send-email 2.25.1 In-Reply-To: <164871505771.178991.7870442736805590948.stgit@devnote2> References: <164871505771.178991.7870442736805590948.stgit@devnote2> User-Agent: StGit/0.19 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This allows kernel developer to embed a default bootconfig file in the kernel instead of embedding it in the initrd. This will be good for who are using the kernel without initrd, or who needs a default bootconfigs. This needs to set two kconfigs: CONFIG_BOOT_CONFIG_EMBED=3Dy and set the file path to CONFIG_BOOT_CONFIG_EMBED_FILE. Note that you still need 'bootconfig' command line option to load the embedded bootconfig. Also if you boot using an initrd with a different bootconfig, the kernel will use the bootconfig in the initrd, instead of the default bootconfig. Signed-off-by: Masami Hiramatsu --- Changes in v7: - Change kconfig option name to share the common prefix so that we can search it easier. - Make embedded_bootconfig_data readonly. - Select CONFIG_BLK_DEV_INITRD only if CONFIG_BOOT_CONFIG_EMBED=3Dn - Remove redundant default settings for new Kconfig options. Changes in v6: - Split out the .incbin asm part as bootconfig-data.S according to Masahiro's comment. Changes in v5: - Fix .gitignore to be sorted alphabetically. - Make default.bconf is cleaned up correctly. - Allow user to specify relative path to CONFIG_EMBED_BOOT_CONFIG_FILE. (Thanks Masahiro!) Changes in v4: - Avoid updating the default.bconf if the file is not changed. --- MAINTAINERS | 1 + include/linux/bootconfig.h | 10 ++++++++++ init/Kconfig | 21 ++++++++++++++++++++- init/main.c | 20 +++++++++++--------- lib/.gitignore | 1 + lib/Makefile | 8 ++++++++ lib/bootconfig-data.S | 10 ++++++++++ lib/bootconfig.c | 13 +++++++++++++ 8 files changed, 74 insertions(+), 10 deletions(-) create mode 100644 lib/bootconfig-data.S diff --git a/MAINTAINERS b/MAINTAINERS index b555a5e8704f..9b4910685412 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -7350,6 +7350,7 @@ S: Maintained F: Documentation/admin-guide/bootconfig.rst F: fs/proc/bootconfig.c F: include/linux/bootconfig.h +F: lib/bootconfig-data.S F: lib/bootconfig.c F: tools/bootconfig/* F: tools/bootconfig/scripts/* diff --git a/include/linux/bootconfig.h b/include/linux/bootconfig.h index a4665c7ab07c..1611f9db878e 100644 --- a/include/linux/bootconfig.h +++ b/include/linux/bootconfig.h @@ -289,4 +289,14 @@ int __init xbc_get_info(int *node_size, size_t *data_s= ize); /* XBC cleanup data structures */ void __init xbc_exit(void); =20 +/* XBC embedded bootconfig data in kernel */ +#ifdef CONFIG_BOOT_CONFIG_EMBED +const char * __init xbc_get_embedded_bootconfig(size_t *size); +#else +static inline const char *xbc_get_embedded_bootconfig(size_t *size) +{ + return NULL; +} +#endif + #endif diff --git a/init/Kconfig b/init/Kconfig index 97463a33baa7..756872d17fe1 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1351,7 +1351,7 @@ endif =20 config BOOT_CONFIG bool "Boot config support" - select BLK_DEV_INITRD + select BLK_DEV_INITRD if !BOOT_CONFIG_EMBED help Extra boot config allows system admin to pass a config file as complemental extension of kernel cmdline when booting. @@ -1361,6 +1361,25 @@ config BOOT_CONFIG =20 If unsure, say Y. =20 +config BOOT_CONFIG_EMBED + bool "Embed bootconfig file in the kernel" + depends on BOOT_CONFIG + help + Embed a bootconfig file given by BOOT_CONFIG_EMBED_FILE in the + kernel. Usually, the bootconfig file is loaded with the initrd + image. But if the system doesn't support initrd, this option will + help you by embedding a bootconfig file while building the kernel. + + If unsure, say N. + +config BOOT_CONFIG_EMBED_FILE + string "Embedded bootconfig file path" + depends on BOOT_CONFIG_EMBED + help + Specify a bootconfig file which will be embedded to the kernel. + This bootconfig will be used if there is no initrd or no other + bootconfig in the initrd. + choice prompt "Compiler optimization level" default CC_OPTIMIZE_FOR_PERFORMANCE diff --git a/init/main.c b/init/main.c index 266d61bc67b0..62dddc4206b4 100644 --- a/init/main.c +++ b/init/main.c @@ -266,7 +266,7 @@ static int __init loglevel(char *str) early_param("loglevel", loglevel); =20 #ifdef CONFIG_BLK_DEV_INITRD -static void * __init get_boot_config_from_initrd(u32 *_size) +static void * __init get_boot_config_from_initrd(size_t *_size) { u32 size, csum; char *data; @@ -410,14 +410,16 @@ static int __init warn_bootconfig(char *str) static void __init setup_boot_config(void) { static char tmp_cmdline[COMMAND_LINE_SIZE] __initdata; - const char *msg; - int pos; - u32 size; - char *data, *err; - int ret; + const char *msg, *data; + int pos, ret; + size_t size; + char *err; =20 /* Cut out the bootconfig data even if we have no bootconfig option */ data =3D get_boot_config_from_initrd(&size); + /* If there is no bootconfig in initrd, try embedded one. */ + if (!data) + data =3D xbc_get_embedded_bootconfig(&size); =20 strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE); err =3D parse_args("bootconfig", tmp_cmdline, NULL, 0, 0, 0, NULL, @@ -436,8 +438,8 @@ static void __init setup_boot_config(void) } =20 if (size >=3D XBC_DATA_MAX) { - pr_err("bootconfig size %d greater than max size %d\n", - size, XBC_DATA_MAX); + pr_err("bootconfig size %ld greater than max size %d\n", + (long)size, XBC_DATA_MAX); return; } =20 @@ -450,7 +452,7 @@ static void __init setup_boot_config(void) msg, pos); } else { xbc_get_info(&ret, NULL); - pr_info("Load bootconfig: %d bytes %d nodes\n", size, ret); + pr_info("Load bootconfig: %ld bytes %d nodes\n", (long)size, ret); /* keys starting with "kernel." are passed via cmdline */ extra_command_line =3D xbc_make_cmdline("kernel"); /* Also, "init." keys are init arguments */ diff --git a/lib/.gitignore b/lib/.gitignore index e5e217b8307b..54596b634ecb 100644 --- a/lib/.gitignore +++ b/lib/.gitignore @@ -1,6 +1,7 @@ # SPDX-License-Identifier: GPL-2.0-only /crc32table.h /crc64table.h +/default.bconf /gen_crc32table /gen_crc64table /oid_registry_data.c diff --git a/lib/Makefile b/lib/Makefile index 08053df16c7c..95268d6c75b7 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -280,6 +280,14 @@ $(foreach file, $(libfdt_files), \ lib-$(CONFIG_LIBFDT) +=3D $(libfdt_files) =20 obj-$(CONFIG_BOOT_CONFIG) +=3D bootconfig.o +obj-$(CONFIG_BOOT_CONFIG_EMBED) +=3D bootconfig-data.o + +$(obj)/bootconfig-data.o: $(obj)/default.bconf + +targets +=3D default.bconf +filechk_defbconf =3D cat $(or $(real-prereqs), /dev/null) +$(obj)/default.bconf: $(CONFIG_BOOT_CONFIG_EMBED_FILE) FORCE + $(call filechk,defbconf) =20 obj-$(CONFIG_RBTREE_TEST) +=3D rbtree_test.o obj-$(CONFIG_INTERVAL_TREE_TEST) +=3D interval_tree_test.o diff --git a/lib/bootconfig-data.S b/lib/bootconfig-data.S new file mode 100644 index 000000000000..ef85ba1a82f4 --- /dev/null +++ b/lib/bootconfig-data.S @@ -0,0 +1,10 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Embed default bootconfig in the kernel. + */ + .section .init.rodata, "aw" + .global embedded_bootconfig_data +embedded_bootconfig_data: + .incbin "lib/default.bconf" + .global embedded_bootconfig_data_end +embedded_bootconfig_data_end: diff --git a/lib/bootconfig.c b/lib/bootconfig.c index 74f3201ab8e5..c59d26068a64 100644 --- a/lib/bootconfig.c +++ b/lib/bootconfig.c @@ -12,6 +12,19 @@ #include #include #include + +#ifdef CONFIG_BOOT_CONFIG_EMBED +/* embedded_bootconfig_data is defined in bootconfig-data.S */ +extern __visible const char embedded_bootconfig_data[]; +extern __visible const char embedded_bootconfig_data_end[]; + +const char * __init xbc_get_embedded_bootconfig(size_t *size) +{ + *size =3D embedded_bootconfig_data_end - embedded_bootconfig_data; + return (*size) ? embedded_bootconfig_data : NULL; +} +#endif + #else /* !__KERNEL__ */ /* * NOTE: This is only for tools/bootconfig, because tools/bootconfig will From nobody Fri Jun 19 17:59:41 2026 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 01E6DC433EF for ; Thu, 31 Mar 2022 08:25:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232773AbiCaI1W (ORCPT ); Thu, 31 Mar 2022 04:27:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56634 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232785AbiCaI07 (ORCPT ); Thu, 31 Mar 2022 04:26:59 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 999E81BB794; Thu, 31 Mar 2022 01:25:11 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 4B01DB82005; Thu, 31 Mar 2022 08:25:10 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6C1E4C340ED; Thu, 31 Mar 2022 08:25:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1648715109; bh=2MxGsdREcZcC5dPhVe4pegMYaaOwE0pzgrqWpuXtrGc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=A1lgvRIuimSfgiCzSsPqrqzPyqJ/Ts6QNUpz89s8ANThoeoFMFD3+ixQA727+HWOq REuBOInQOtfZoLxQGzi1HT1fAoN63Fcit+so0ojLvQ3R/HUlvNitTG8lnnYQ8h2VG4 EVguk8Nk4AnfSV4RKvcwqVp0qg56pDWvHDwKSIT3eIDgeMUjmC5fCwLuZEc4gc6MgE Lt/ifHthtHVcalu9xui4rO+kozd/ZER98FqzuTcfHNdUWqxMtGAc7FeE8lOeakOegP /N2iVe/5PHy066XlyX+NS5o2NF2W9CsvPYLQpvsCKCMdKTcKDTxgdT4v5D0pm0YP/V /8ayKrr16WUaw== From: Masami Hiramatsu To: Steven Rostedt Cc: Masami Hiramatsu , Padmanabha Srinivasaiah , LKML , Jonathan Corbet , linux-doc@vger.kernel.org, Randy Dunlap , Nick Desaulniers , Sami Tolvanen , Nathan Chancellor , llvm@lists.linux.dev, Masahiro Yamada , Linux Kbuild mailing list Subject: [PATCH v7 4/4] docs: bootconfig: Add how to embed the bootconfig into kernel Date: Thu, 31 Mar 2022 17:25:03 +0900 Message-Id: <164871510350.178991.10848731777317835399.stgit@devnote2> X-Mailer: git-send-email 2.25.1 In-Reply-To: <164871505771.178991.7870442736805590948.stgit@devnote2> References: <164871505771.178991.7870442736805590948.stgit@devnote2> User-Agent: StGit/0.19 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add a description how to embed the bootconfig file into kernel. Signed-off-by: Masami Hiramatsu --- Changes in v7: - Rename CONFIG_EMBED_BOOT_CONFIG* to CONFIG_BOOT_CONFIG_EMBED*. Changes in v5: - Update CONFIG_EMBED_BOOT_CONFIG_FILE which can accept relative path. Changes in v3: - Fix typos. Changes in v2: - Corrected the text accoding to Randy's suggestion. - Do not reccomend to use relative path for CONFIG_EMBED_BOOT_CONFIG_FILE. --- Documentation/admin-guide/bootconfig.rst | 31 ++++++++++++++++++++++++++= +--- 1 file changed, 28 insertions(+), 3 deletions(-) diff --git a/Documentation/admin-guide/bootconfig.rst b/Documentation/admin= -guide/bootconfig.rst index a1860fc0ca88..d99994345d41 100644 --- a/Documentation/admin-guide/bootconfig.rst +++ b/Documentation/admin-guide/bootconfig.rst @@ -158,9 +158,15 @@ Each key-value pair is shown in each line with followi= ng style:: Boot Kernel With a Boot Config =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D =20 -Since the boot configuration file is loaded with initrd, it will be added -to the end of the initrd (initramfs) image file with padding, size, -checksum and 12-byte magic word as below. +There are two options to boot the kernel with bootconfig: attaching the +bootconfig to the initrd image or embedding it in the kernel itself. + +Attaching a Boot Config to Initrd +--------------------------------- + +Since the boot configuration file is loaded with initrd by default, +it will be added to the end of the initrd (initramfs) image file with +padding, size, checksum and 12-byte magic word as below. =20 [initrd][bootconfig][padding][size(le32)][checksum(le32)][#BOOTCONFIG\n] =20 @@ -196,6 +202,25 @@ To remove the config from the image, you can use -d op= tion as below:: Then add "bootconfig" on the normal kernel command line to tell the kernel to look for the bootconfig at the end of the initrd file. =20 +Embedding a Boot Config into Kernel +----------------------------------- + +If you can not use initrd, you can also embed the bootconfig file in the +kernel by Kconfig options. In this case, you need to recompile the kernel +with the following configs:: + + CONFIG_BOOT_CONFIG_EMBED=3Dy + CONFIG_BOOT_CONFIG_EMBED_FILE=3D"/PATH/TO/BOOTCONFIG/FILE" + +``CONFIG_BOOT_CONFIG_EMBED_FILE`` requires an absolute path or a relative +path to the bootconfig file from source tree or object tree. +The kernel will embed it as the default bootconfig. + +Just as when attaching the bootconfig to the initrd, you need ``bootconfig= `` +option on the kernel command line to enable the embedded bootconfig. + +Note that even if you set this option, you can override the embedded +bootconfig by another bootconfig which attached to the initrd. =20 Kernel parameters via Boot Config =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D