linux-kernel - Re: [PATCH] Refuse activation of tpm_tis driver if TPM is not working correctly

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Date:	Mon, 10 Oct 2011 10:04:32 -0300
From:	Rajiv Andrade <srajiv@...ux.vnet.ibm.com>
To:	Stefan Berger <stefanb@...ux.vnet.ibm.com>
CC:	"tpmdd-devel@...ts.sourceforge.net" 
	<tpmdd-devel@...ts.sourceforge.net>,
	James Morris <jmorris@...ei.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	m.selhorst@...rix.com, a.miskiewicz@...il.com
Subject: Re: [PATCH] Refuse activation of tpm_tis driver if TPM is not working
 correctly

On 10/10/11 09:16, Stefan Berger wrote:
> Refuse activation of tpm_tis driver if the TPM is found not to be
> working correctly. This prevents suspend/resume problems for me on
> Lenovo W500 and T61p.
>
> Signed-off-by: Stefan Berger<stefanb@...ux.vnet.ibm.com>
Testing and trying to reproduce it here.

Rajiv
>
> ---
>   drivers/char/tpm/tpm_tis.c |   13 +++++++++++++
>   1 files changed, 13 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm_tis.c b/drivers/char/tpm/tpm_tis.c
> index 3f4051a..7f2761d 100644
> --- a/drivers/char/tpm/tpm_tis.c
> +++ b/drivers/char/tpm/tpm_tis.c
> @@ -549,6 +549,7 @@ static int tpm_tis_init(struct device *dev, resource_size_t start,
>   	u32 vendor, intfcaps, intmask;
>   	int rc, i, irq_s, irq_e;
>   	struct tpm_chip *chip;
> +	u8 digest[TPM_DIGEST_SIZE];
>
>   	if (!(chip = tpm_register_hardware(dev,&tpm_tis)))
>   		return -ENODEV;
> @@ -616,6 +617,18 @@ static int tpm_tis_init(struct device *dev, resource_size_t start,
>   	/* get the timeouts before testing for irqs */
>   	tpm_get_timeouts(chip);
>
> +	/* test for correctly working TPM; refuse driver if not working
> +	   to prevent suspend/resume problems */
> +	rc = tpm_pcr_read(chip->dev_num, 0, digest);
> +	if (rc != 0) {
> +		dev_err(dev, "Could not read PCR 0. "
> +			"TPM is not working correctly.\n");
> +		dev_err(dev, "Was machine previously suspended without TPM "
> +			"driver present?\n");
> +		rc = -ENODEV;
> +		goto out_err;
> +	}
> +
>   	/* INTERRUPT Setup */
>   	init_waitqueue_head(&chip->vendor.read_queue);
>   	init_waitqueue_head(&chip->vendor.int_queue);

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