linux-kernel - Re: tpm_tis TPM2.0 not detected on cold boot

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Message-Id: <94e4968b-0b19-f0ca-24d8-e8105c1af704@linux.ibm.com>
Date:   Mon, 31 Dec 2018 12:56:03 -0500
From:   Ken Goldman <kgold@...ux.ibm.com>
To:     Mimi Zohar <zohar@...ux.ibm.com>, linux-integrity@...r.kernel.org,
        linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: tpm_tis TPM2.0 not detected on cold boot

On 12/29/2018 10:33 PM, Mimi Zohar wrote:
> But the problem you've described is on a cold boot, not a soft reboot.
>   Both the soft reboot and kexec are working properly.  It seems the
> difference is that on a cold boot, the TPM takes longer to initialize.

I would expect this.

The TPM doesn't even see a 'soft reboot' right?

OTOH, a 'cold boot' hits the TPM Init pin, which causes the take several
actions.  Probably the one with the most impact is resetting the state
of self test.  Thus, the TPM will require a function to be self tested
before it can be used, adding delays.