From: Jarkko Sakkinen <jarkko@kernel.org>
To: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
Cc: Peter Huewe <peterhuewe@gmx.de>, Jason Gunthorpe <jgg@ziepe.ca>,
linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org,
Jia Zhang <zhang.jia@linux.alibaba.com>
Subject: Re: [PATCH] tpm/tpm_tis: Fix variable reset during IRQ probing
Date: Thu, 14 Jan 2021 04:51:27 +0200 [thread overview]
Message-ID: <X/+xr/L+m2k5fObZ@kernel.org> (raw)
In-Reply-To: <20210113120021.59045-1-tianjia.zhang@linux.alibaba.com>
On Wed, Jan 13, 2021 at 08:00:21PM +0800, Tianjia Zhang wrote:
> In tpm_tis_core_init(), tpm2_probe() will be called first, this
> function will eventually call tpm_tis_send(), and then
> tpm_tis_probe_irq_single() will detect whether the interrupt is
> normal, mainly the installation interrupted, set `priv->irq_tested`
> to false. The logic will eventually be executed to tpm_tis_send()
> to trigger an interrupt.
>
> There is currently such a scenario, which will cause the IRQ probe
> code to never be executed, so that the TPM device is in polling
> mode: after setting irq_tested to false, an interrupt occurs
> between entering the ttpm_tis_send() function, and the interrupt
> will be first set irq_tested to true will cause the IRQ probe code
> to never be executed.
Can you describe the scenario more detail?
> It seems that this interrupt comes from tpm2_probe(). Although the
> interrupt has not been installed when tpm2_probe() is called, the
> interrupt of tpm2_probe() is only received after IRQ detection.
>
> This patch solves this issue by introducing a new variable, which
> is only used in interrupts, and irq_tested only marks whether the
> interrupt test has been completed.
>
> Signed-off-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
> ---
I'm not sure I understand this patch. TPM should be in polling
mode. This is also assumption before calling tpm_get_timeouts():
/* Before doing irq testing issue a command to the TPM in polling mode
* to make sure it works. May as well use that command to set the
* proper timeouts for the driver.
*/
if (tpm_get_timeouts(chip)) {
dev_err(dev, "Could not get TPM timeouts and durations\n");
rc = -ENODEV;
goto out_err;
}
/Jarkko
next prev parent reply other threads:[~2021-01-14 2:52 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-13 12:00 [PATCH] tpm/tpm_tis: Fix variable reset during IRQ probing Tianjia Zhang
2021-01-14 2:51 ` Jarkko Sakkinen [this message]
2021-01-14 4:12 ` Tianjia Zhang
2021-01-15 9:23 ` Jarkko Sakkinen
2021-01-20 4:03 ` Tianjia Zhang
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