On Fri, 17 Apr 2026 08:38:16 -0700 Breno Leitao <[email protected]> wrote:
> > On Fri, Apr 17, 2026 at 10:44:36AM +0900, Masami Hiramatsu wrote: > > On Wed, 15 Apr 2026 03:51:11 -0700 > > Breno Leitao <[email protected]> wrote: > > > > But if we can do it, should we continue using bootconfig? I mean > > it is easy to make a tool (or add a feature in tools/bootconfig) > > which converts bootconfig file to command line string and embeds > > it in the kernel. Hmm. > > Sure, you are talking about a a tool that embeddeds it in the kernel binary, > something like: > > > 0) Get a kernel and define CONFIG_BOOT_CONFIG_EMBED_FILE=".bootconfig" > > 1) Add an option in tools/bootconfig to convert bootconfig (.bootconfig) > to a cmdline string ($ bootconfig -C kernel .bootconfig). > Something like: > # tools/bootconfig/bootconfig -C kernel .bootconfig > mem=2G loglevel=7 debug nokaslr % > > 2) At kernel build time, run that tool on .bootconfig and embed the > resulting string into the kernel image as a .init.rodata symbol > (embedded_kernel_cmdline[]). > > # gdb -batch -ex 'x/s &embedded_kernel_cmdline' vmlinux > 0xffffffff87e108f8: "mem=2G loglevel=7 debug nokaslr " Yeah, I think this looks good to me. > > 3) At boot, the arch's setup_arch() prepends that symbol to > boot_command_line right before parse_early_param() — so early_param() > handlers (mem=, earlycon=, loglevel=, ...) actually see kernel.* > keys from the embedded bootconfig. Ah, I thought it is arch independent config, but it depends on architecture.... Hmm. > > This needs to be architecture by architecture. Something like: > > @@ -924,6 +925,13 @@ void __init setup_arch(char **cmdline_p) > builtin_cmdline_added = true; > #endif > > + /* > + * Prepend kernel.* keys from the embedded bootconfig (rendered > at > + * build time by tools/bootconfig) so parse_early_param() below > sees > + * them. No-op when CONFIG_BOOT_CONFIG_EMBED=n. > + */ > + xbc_prepend_embedded_cmdline(boot_command_line, > COMMAND_LINE_SIZE); > + > strscpy(command_line, boot_command_line, COMMAND_LINE_SIZE); > *cmdline_p = command_line; > > Am I describing your suggestion accordingly? I think we can start supporting this option for the architecture which already support CONFIG_CMDLINE. Maybe we need CONFIG_ARCH_SUPPORT_CMDLINE option which indicates the architecture supports embedded cmdline. Thus all of this feature can depend on that Kconfig. Thank you, > > Thanks! > --breno -- Masami Hiramatsu (Google) <[email protected]>
