From patchwork Wed Apr 27 19:36:33 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Rostedt X-Patchwork-Id: 12829452 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 6C6E8C433EF for ; Wed, 27 Apr 2022 19:36:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232881AbiD0Tjz (ORCPT ); Wed, 27 Apr 2022 15:39:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45866 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231127AbiD0Tjz (ORCPT ); Wed, 27 Apr 2022 15:39:55 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5BB1A109D; Wed, 27 Apr 2022 12:36:43 -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 6FC6361B72; Wed, 27 Apr 2022 19:36:42 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 49CEEC385B0; Wed, 27 Apr 2022 19:36:42 +0000 (UTC) Received: from rostedt by gandalf.local.home with local (Exim 4.95) (envelope-from ) id 1njnSr-002Ith-Dh; Wed, 27 Apr 2022 15:36:41 -0400 Message-ID: <20220427193641.259144310@goodmis.org> User-Agent: quilt/0.66 Date: Wed, 27 Apr 2022 15:36:33 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , Padmanabha Srinivasaiah , Jonathan Corbet , Randy Dunlap , Nick Desaulniers , Sami Tolvanen , Nathan Chancellor , Linux Kbuild mailing list , Masahiro Yamada , Masami Hiramatsu Subject: [for-next][PATCH 10/21] bootconfig: Make the bootconfig.o as a normal object file References: <20220427193623.529296556@goodmis.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org From: Masami Hiramatsu 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. Link: https://lkml.kernel.org/r/164921225875.1090670.15565363126983098971.stgit@devnote2 Cc: Padmanabha Srinivasaiah Cc: Jonathan Corbet Cc: Randy Dunlap Cc: Nick Desaulniers Cc: Sami Tolvanen Cc: Nathan Chancellor Cc: Linux Kbuild mailing list Reported-by: Masahiro Yamada Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (Google) --- 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) = -I $(srctree)/scripts/dtc/libfdt)) lib-$(CONFIG_LIBFDT) += $(libfdt_files) -lib-$(CONFIG_BOOT_CONFIG) += bootconfig.o +obj-$(CONFIG_BOOT_CONFIG) += bootconfig.o obj-$(CONFIG_RBTREE_TEST) += rbtree_test.o obj-$(CONFIG_INTERVAL_TREE_TEST) += interval_tree_test.o From patchwork Wed Apr 27 19:36:34 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Rostedt X-Patchwork-Id: 12829453 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 C5158C433F5 for ; Wed, 27 Apr 2022 19:36:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233400AbiD0Tj4 (ORCPT ); Wed, 27 Apr 2022 15:39:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46252 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231273AbiD0Tjz (ORCPT ); Wed, 27 Apr 2022 15:39:55 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D281BD7B; Wed, 27 Apr 2022 12:36:43 -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 BAC7861B86; Wed, 27 Apr 2022 19:36:42 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 92C09C385C6; Wed, 27 Apr 2022 19:36:42 +0000 (UTC) Received: from rostedt by gandalf.local.home with local (Exim 4.95) (envelope-from ) id 1njnSr-002IuG-Jm; Wed, 27 Apr 2022 15:36:41 -0400 Message-ID: <20220427193641.440543712@goodmis.org> User-Agent: quilt/0.66 Date: Wed, 27 Apr 2022 15:36:34 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , Padmanabha Srinivasaiah , Jonathan Corbet , Randy Dunlap , Nick Desaulniers , Sami Tolvanen , Nathan Chancellor , Masahiro Yamada , Linux Kbuild mailing list , Masami Hiramatsu Subject: [for-next][PATCH 11/21] bootconfig: Check the checksum before removing the bootconfig from initrd References: <20220427193623.529296556@goodmis.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org From: Masami Hiramatsu Check the bootconfig's checksum before removing the bootconfig data from initrd to avoid modifying initrd by mistake. This will also simplifies the get_boot_config_from_initrd() interface. Link: https://lkml.kernel.org/r/164921226891.1090670.16955839243639298134.stgit@devnote2 Cc: Padmanabha Srinivasaiah Cc: Jonathan Corbet Cc: Randy Dunlap Cc: Nick Desaulniers Cc: Sami Tolvanen Cc: Nathan Chancellor Cc: Masahiro Yamada Cc: Linux Kbuild mailing list Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (Google) --- 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); #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; } + if (xbc_calc_checksum(data, size) != csum) { + pr_err("bootconfig checksum failed\n"); + return NULL; + } + /* Remove bootconfig from initramfs/initrd */ initrd_end = (unsigned long)data; if (_size) *_size = size; - if (_csum) - *_csum = csum; 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; /* Cut out the bootconfig data even if we have no bootconfig option */ - data = get_boot_config_from_initrd(&size, &csum); + data = get_boot_config_from_initrd(&size); strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE); err = parse_args("bootconfig", tmp_cmdline, NULL, 0, 0, 0, NULL, @@ -438,11 +441,6 @@ static void __init setup_boot_config(void) return; } - if (xbc_calc_checksum(data, size) != csum) { - pr_err("bootconfig checksum failed\n"); - return; - } - ret = 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); } static int __init warn_bootconfig(char *str) From patchwork Wed Apr 27 19:36:35 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Rostedt X-Patchwork-Id: 12829455 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 8F941C433EF for ; Wed, 27 Apr 2022 19:37:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230113AbiD0TkX (ORCPT ); Wed, 27 Apr 2022 15:40:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46298 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232879AbiD0Tj4 (ORCPT ); Wed, 27 Apr 2022 15:39:56 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F20C1E5D; Wed, 27 Apr 2022 12:36:43 -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 DFCE761B8E; Wed, 27 Apr 2022 19:36:42 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id AAD7BC385C3; Wed, 27 Apr 2022 19:36:42 +0000 (UTC) Received: from rostedt by gandalf.local.home with local (Exim 4.95) (envelope-from ) id 1njnSr-002Iuq-Q5; Wed, 27 Apr 2022 15:36:41 -0400 Message-ID: <20220427193641.651401737@goodmis.org> User-Agent: quilt/0.66 Date: Wed, 27 Apr 2022 15:36:35 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , Padmanabha Srinivasaiah , Jonathan Corbet , Randy Dunlap , Nick Desaulniers , Sami Tolvanen , Nathan Chancellor , Masahiro Yamada , Linux Kbuild mailing list , Masami Hiramatsu Subject: [for-next][PATCH 12/21] bootconfig: Support embedding a bootconfig file in kernel References: <20220427193623.529296556@goodmis.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org From: Masami Hiramatsu 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=y 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. Link: https://lkml.kernel.org/r/164921227943.1090670.14035119557571329218.stgit@devnote2 Cc: Padmanabha Srinivasaiah Cc: Jonathan Corbet Cc: Randy Dunlap Cc: Nick Desaulniers Cc: Sami Tolvanen Cc: Nathan Chancellor Cc: Masahiro Yamada Cc: Linux Kbuild mailing list Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (Google) --- MAINTAINERS | 1 + include/linux/bootconfig.h | 10 ++++++++++ init/Kconfig | 21 ++++++++++++++++++++- init/main.c | 22 ++++++++++++---------- lib/.gitignore | 1 + lib/Makefile | 8 ++++++++ lib/bootconfig-data.S | 10 ++++++++++ lib/bootconfig.c | 13 +++++++++++++ 8 files changed, 75 insertions(+), 11 deletions(-) create mode 100644 lib/bootconfig-data.S diff --git a/MAINTAINERS b/MAINTAINERS index b90535d923a0..abc8e6fee21e 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -7457,6 +7457,7 @@ 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_size); /* XBC cleanup data structures */ void __init xbc_exit(void); +/* 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 ddcbefe535e9..2462d4ae2dc8 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1351,7 +1351,7 @@ endif 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 If unsure, say Y. +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..f7fe7cbb1df8 100644 --- a/init/main.c +++ b/init/main.c @@ -266,7 +266,7 @@ static int __init loglevel(char *str) early_param("loglevel", loglevel); #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; @@ -313,7 +313,7 @@ static void * __init get_boot_config_from_initrd(u32 *_size) return data; } #else -static void * __init get_boot_config_from_initrd(u32 *_size) +static void * __init get_boot_config_from_initrd(size_t *_size) { return NULL; } @@ -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; /* Cut out the bootconfig data even if we have no bootconfig option */ data = get_boot_config_from_initrd(&size); + /* If there is no bootconfig in initrd, try embedded one. */ + if (!data) + data = xbc_get_embedded_bootconfig(&size); strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE); err = parse_args("bootconfig", tmp_cmdline, NULL, 0, 0, 0, NULL, @@ -436,8 +438,8 @@ static void __init setup_boot_config(void) } if (size >= 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; } @@ -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 = 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) += $(libfdt_files) obj-$(CONFIG_BOOT_CONFIG) += bootconfig.o +obj-$(CONFIG_BOOT_CONFIG_EMBED) += bootconfig-data.o + +$(obj)/bootconfig-data.o: $(obj)/default.bconf + +targets += default.bconf +filechk_defbconf = cat $(or $(real-prereqs), /dev/null) +$(obj)/default.bconf: $(CONFIG_BOOT_CONFIG_EMBED_FILE) FORCE + $(call filechk,defbconf) obj-$(CONFIG_RBTREE_TEST) += rbtree_test.o obj-$(CONFIG_INTERVAL_TREE_TEST) += 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 = 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 patchwork Wed Apr 27 19:36:36 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Rostedt X-Patchwork-Id: 12829454 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 8274EC433FE for ; Wed, 27 Apr 2022 19:36:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233807AbiD0Tj6 (ORCPT ); Wed, 27 Apr 2022 15:39:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46306 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233331AbiD0Tj4 (ORCPT ); Wed, 27 Apr 2022 15:39:56 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2C964FEE; Wed, 27 Apr 2022 12:36:44 -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 12BC261B8A; Wed, 27 Apr 2022 19:36:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E17A4C385B1; Wed, 27 Apr 2022 19:36:42 +0000 (UTC) Received: from rostedt by gandalf.local.home with local (Exim 4.95) (envelope-from ) id 1njnSs-002IvQ-0P; Wed, 27 Apr 2022 15:36:42 -0400 Message-ID: <20220427193641.826142252@goodmis.org> User-Agent: quilt/0.66 Date: Wed, 27 Apr 2022 15:36:36 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , Padmanabha Srinivasaiah , Jonathan Corbet , Randy Dunlap , Nick Desaulniers , Sami Tolvanen , Nathan Chancellor , Masahiro Yamada , Linux Kbuild mailing list , Masami Hiramatsu Subject: [for-next][PATCH 13/21] docs: bootconfig: Add how to embed the bootconfig into kernel References: <20220427193623.529296556@goodmis.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org From: Masami Hiramatsu Add a description how to embed the bootconfig file into kernel. Link: https://lkml.kernel.org/r/164921228987.1090670.16843569536974147213.stgit@devnote2 Cc: Padmanabha Srinivasaiah Cc: Jonathan Corbet Cc: Randy Dunlap Cc: Nick Desaulniers Cc: Sami Tolvanen Cc: Nathan Chancellor Cc: Masahiro Yamada Cc: Linux Kbuild mailing list Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (Google) --- 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 following style:: Boot Kernel With a Boot Config ============================== -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. [initrd][bootconfig][padding][size(le32)][checksum(le32)][#BOOTCONFIG\n] @@ -196,6 +202,25 @@ To remove the config from the image, you can use -d option 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. +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=y + CONFIG_BOOT_CONFIG_EMBED_FILE="/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. Kernel parameters via Boot Config =================================