linux-kernel - Re: [PATCH 2/2] tpm: tpm_crb_ffa: maunally register tpm_crb

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Message-ID: <aEdLOb3V3EgBZJof@kernel.org>
Date: Mon, 9 Jun 2025 23:59:37 +0300
From: Jarkko Sakkinen <jarkko@...nel.org>
To: Yeoreum Yun <yeoreum.yun@....com>
Cc: sudeep.holla@....com, peterhuewe@....de, jgg@...pe.ca,
	stuart.yoder@....com, linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org, linux-integrity@...r.kernel.org
Subject: Re: [PATCH 2/2] tpm: tpm_crb_ffa: maunally register tpm_crb_ffa
 driver when it's built-in

On Fri, Jun 06, 2025 at 07:12:43PM +0100, Yeoreum Yun wrote:
> Hi Jarkko,
> 
> > > To integrate tpm_event_log with IMA subsystem,
> > > tpm_crb and tpm_crb_ffa driver should be built as built-in
> > > (CONFIG_TCG_CRB=y && CONFIG_TCG_CRB_FFA=y).
> > >
> > > However, this could make failure for ima_init() gets tpm chip when
> > > each initcall function deployed like:
> > >
> > > 0000000000000888 l       .initcall6.init	0000000000000000 crb_acpi_driver_init
> > > 000000000000088c l       .initcall6.init	0000000000000000 tpm_crb_ffa_driver_init
> >
> > The only failure I see is the patch 1/2 which changes init call level,
> > and leaves kernel Git to a broken state.
> >
> > It breaks the famous "zero regressions policy".
> >
> > BR, Jarkko
> 
> Sorry, would you let me know what is broken more detail?
> IMHO, by changing the init call level for ffa_init()
> it's called early than before device_initcall() and it seems not to
> break anything.
> 
> What breaks do you mean?

Your description in the cover letter and commit messages in unclear
and convoluted. Please describe exact causalities instead of something
not defined could cause "failure" (which is also abstract concept).

I'll check the next round.

> 
> Thanks.
> 
> --
> Sincerely,
> Yeoreum Yun

BR, Jarkko