Re: tracing : bootconfig : Early boot config for non intrd systems

[Masami Hiramatsu]

On Tue, 8 Mar 2022 18:48:29 +0100
Padmanabha Srinivasaiah <treasure4paddy@xxxxxxxxx> wrote:

> Hello Masami Hiramatsu,
> 
> On Tue, Mar 08, 2022 at 04:36:00PM +0900, Masami Hiramatsu wrote:
> > Hello Padmanabha,
> > 
> > On Mon, 7 Mar 2022 19:40:11 +0100
> > Padmanabha Srinivasaiah <treasure4paddy@xxxxxxxxx> wrote:
> > 
> > > Hello Masami Hiramatsu,
> > > 
> > > Thanks for detailed explanation on boot time tracing using early boot configuration file.
> > > https://linuxfoundation.org/wp-content/uploads/boottrace-LF-live-2021-update.pdf
> > > 
> > > Also for https://lwn.net/Articles/806002/.
> > > 
> > > Latter link also states we can embed boot config into the kernel image for non intrd based system.
> > 
> > Ah, that was an original plan, but since no one interested in, I didn't implement it.
> > So we still need the initrd for bootconfig.
> >
> Ok.
> > > 
> > > I tried searching mailing lists not able to find pointer for same.
> > > 
> > > A hint/pointer on how-to will be very helpful. 
> > 
> > BTW, what is your problem, could you share your use-case?
> > 
> 
> I have hetrogenous system which donot use intrd.
> 
> The use-case is to capture __system wide__ event based tracing for
> boot-up sequence, which also covers early stage of default init programs
> used.
> 
> As buffer size is limited, will have hand-picked events set configured.

Hm, so I guess you will boot linux from your custom bootloader (or binary loader on sub processor?).

Can you even try to add a dummy initrd? or are you OK to rebuild kernel for embedding the bootconfig data?
If both don't work, the solution will be architecture or bootloader specific.

Thank you,

-- 
Masami Hiramatsu <mhiramat@xxxxxxxxxx>