On Thu, Mar 31, 2022 at 3:49 PM Masami Hiramatsu <mhiramat@xxxxxxxxxx> wrote: > > On Thu, 31 Mar 2022 15:27:56 +0900 > Masahiro Yamada <masahiroy@xxxxxxxxxx> wrote: > > > On Thu, Mar 31, 2022 at 2:56 PM Masami Hiramatsu <mhiramat@xxxxxxxxxx> wrote: > > > > > > 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_EMBED_BOOT_CONFIG=y and set > > > the file path to CONFIG_EMBED_BOOT_CONFIG_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 <mhiramat@xxxxxxxxxx> > > > --- > > > 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 | 13 ++++++++----- > > > lib/.gitignore | 1 + > > > lib/Makefile | 8 ++++++++ > > > lib/bootconfig-data.S | 11 +++++++++++ > > > lib/bootconfig.c | 13 +++++++++++++ > > > 8 files changed, 73 insertions(+), 5 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..5dbda5e3e9bb 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_EMBED_BOOT_CONFIG > > > +char * __init xbc_get_embedded_bootconfig(size_t *size); > > > +#else > > > +static inline char *xbc_get_embedded_bootconfig(size_t *size) > > > +{ > > > + return NULL; > > > +} > > > +#endif > > > + > > > #endif > > > diff --git a/init/Kconfig b/init/Kconfig > > > index 97463a33baa7..f5d14a78cfce 100644 > > > --- a/init/Kconfig > > > +++ b/init/Kconfig > > > @@ -1361,6 +1361,27 @@ config BOOT_CONFIG > > > > > > If unsure, say Y. > > > > > > +config EMBED_BOOT_CONFIG > > > + bool "Embed bootconfig file in the kernel" > > > + depends on BOOT_CONFIG > > > + default n > > > + help > > > + Embed a bootconfig file given by EMBED_BOOT_CONFIG_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 EMBED_BOOT_CONFIG_FILE > > > + string "Embedded bootconfig file path" > > > + default "" > > > + depends on EMBED_BOOT_CONFIG > > > + 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..a5db3e36b809 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; > > > @@ -412,12 +412,15 @@ static void __init setup_boot_config(void) > > > static char tmp_cmdline[COMMAND_LINE_SIZE] __initdata; > > > const char *msg; > > > int pos; > > > - u32 size; > > > + size_t 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); > > > + /* 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 +439,8 @@ 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 +453,7 @@ 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..2a82cc324f91 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-$(CONFIG_EMBED_BOOT_CONFIG) += bootconfig-data.o > > > + > > > +$(obj)/bootconfig-data.o: $(obj)/default.bconf > > > + > > > +targets += default.bconf > > > +filechk_defbconf = cat $(or $(real-prereqs), /dev/null) > > > +$(obj)/default.bconf: $(CONFIG_EMBED_BOOT_CONFIG_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..df674ea7d8be > > > --- /dev/null > > > +++ b/lib/bootconfig-data.S > > > @@ -0,0 +1,11 @@ > > > +/* SPDX-License-Identifier: GPL-2.0 */ > > > +/* > > > + * Embed default bootconfig in the kernel. > > > + */ > > > + .pushsection .init.data, "aw" > > > + .global embedded_bootconfig_data > > > +embedded_bootconfig_data: > > > + .incbin "lib/default.bconf" > > > + .global embedded_bootconfig_data_end > > > +embedded_bootconfig_data_end: > > > + .popsection > > > > > > > > You used .pushsection / .popsection because it was > > previously located in bootconfig.c, where there are > > functions, which should go to the ".text" section. > > Oops, yes. I have made a dumb copy from the inline asm... > > > Now that you split this into a separate compilation unit, > > there is only one ".init.data" section in the file. > > > > > > .section .init.data, "aw" > > > > should be enough. > > OK. > > > BTW, is it reasonable/possible to make it explicitly read-only? > > > > I have not tested this patch at all. Nor do I have enough insight. > > > > .section .init.rodata, "a" > > > > I am not sure whether this is possible or not. > > Yes, it can be. The data is passed via 'const char *'. But, you didn't add "const" in the C code: extern __visible char embedded_bootconfig_data[]; extern __visible char embedded_bootconfig_data_end[]; Is it possible to use "const char" ? -- Best Regards Masahiro Yamada