linux-kernel - Re: [PATCH] tpm_tis_core: Set TPM_CHIP_FLAG

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Date:   Sun, 08 Sep 2019 00:21:46 +0300
From:   Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
To:     Jan Lübbe <jlu@...gutronix.de>,
        Stefan Berger <stefanb@...ux.vnet.ibm.com>
Cc:     linux-security-module@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-integrity@...r.kernel.org,
        Stefan Berger <stefanb@...ux.ibm.com>,
        linux-stable@...r.kernel.org
Subject: Re: [PATCH] tpm_tis_core: Set TPM_CHIP_FLAG_IRQ before probing for
 interrupts

On Fri, 2019-09-06 at 14:37 +0200, Jan Lübbe wrote:
> This is due to the SPI accesses performed by tis_int_handler (which
> will sleep). Switching to devm_request_threaded_irq fixes this and
> leads to a successful IRQ probe.

Aah, right through tpm_tis_read32/write32(). This is definitely a new
regression. Thanks for reporting this! This was completely missed when
the support for other than TCG MMIO was implemented for the TIS driver.

This should have a patch of it own with your reported-by unless you
care to send bug fix for it.

> But: It seems that the IRQ is not acked correctly, as the interrupt
> line stays low. I suspect this is because the tpm_chip_stop from
> http://git.infradead.org/users/jjs/linux-tpmdd.git/commitdiff/9b558deab2c5d7dc23d5f7a4064892ede482ad32
> happens before the threaded handler runs. I'm currently unable to
> verify that though, as my build machine's disk just died. :/

I cannot recall all the nyances related to interrupt probing but with a
quick look I wonder why it does not utilize int_queue. Then
tpm_chip_stop() could be done synchronously.

> Regards,
> Jan

/Jarkko