On Sat, 7 Jan 2023 08:22:02 -0800 "Paul E. McKenney" <paulmck@xxxxxxxxxx> wrote: > On Sun, Jan 08, 2023 at 12:22:15AM +0900, Masami Hiramatsu wrote: > > On Wed, 4 Jan 2023 16:58:38 -0800 > > "Paul E. McKenney" <paulmck@xxxxxxxxxx> wrote: > > > > > The BOOT_CONFIG family of Kconfig options allows a bootconfig file > > > containing kernel boot parameters to be embedded into an initrd or into > > > the kernel itself. This can be extremely useful when deploying kernels > > > in cases where some of the boot parameters depend on the kernel version > > > rather than on the server hardware, firmware, or workload. > > > > > > Unfortunately, the "bootconfig" kernel parameter must be specified in > > > order to cause the kernel to look for the embedded bootconfig file, > > > and it clearly does not help to embed this "bootconfig" kernel parameter > > > into that file. > > > > > > Therefore, provide a new BOOT_CONFIG_FORCE Kconfig option that causes the > > > kernel to act as if the "bootconfig" kernel parameter had been specified. > > > In other words, kernels built with CONFIG_BOOT_CONFIG_FORCE=y will look > > > for the embedded bootconfig file even when the "bootconfig" kernel > > > parameter is omitted. This permits kernel-version-dependent kernel > > > boot parameters to be embedded into the kernel image without the need to > > > (for example) update large numbers of boot loaders. > > > > I like this because this is a simple solution. We have another option > > to specify "bootconfig" in CONFIG_CMDLINE, but it can be overwritten by > > bootloader. Thus, it is better to have this option so that user can > > always enable bootconfig. > > Glad you like it! > > In addition, if the help text is accurate, another shortcoming of > CONFIG_CMDLINE is that its semantics vary from one architecture to > another. Some have CONFIG_CMDLINE override the boot-loader supplied > parameters, and others differ in the order in which the parameters > are processed. Yes, that differences confuse us... > > > Acked-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx> > > Thank you! > > > BTW, maybe CONFIG_BOOT_CONFIG_EMBED is better to select this. > > (or at least recommend to enable this) > > Like this? Yes! Thanks. > > Thanx, Paul > > ------------------------------------------------------------------------ > > commit d09a1505c51a70da38b34ac38062977299aef742 > Author: Paul E. McKenney <paulmck@xxxxxxxxxx> > Date: Sat Jan 7 08:09:22 2023 -0800 > > bootconfig: Default BOOT_CONFIG_FORCE to y if BOOT_CONFIG_EMBED > > When a kernel is built with CONFIG_BOOT_CONFIG_EMBED=y, the intention > will normally be to unconditionally provide the specified kernel-boot > arguments to the kernel, as opposed to requiring a separately provided > bootconfig parameter. Therefore, make the BOOT_CONFIG_FORCE Kconfig > option default to y in kernels built with CONFIG_BOOT_CONFIG_EMBED=y. > > The old semantics may be obtained by manually overriding this default. > > Suggested-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx> > Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx> Acked-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx> Thank you! > > diff --git a/init/Kconfig b/init/Kconfig > index 0fb19fa0edba9..97a0f14d9020d 100644 > --- a/init/Kconfig > +++ b/init/Kconfig > @@ -1379,6 +1379,7 @@ config BOOT_CONFIG > config BOOT_CONFIG_FORCE > bool "Force unconditional bootconfig processing" > depends on BOOT_CONFIG > + default y if BOOT_CONFIG_EMBED > help > With this Kconfig option set, BOOT_CONFIG processing is carried > out even when the "bootconfig" kernel-boot parameter is omitted. -- Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
