linux-kernel - Re: [PATCH v3 3/7] tpm_tis: Do not fall back to a hardcoded address for TPM2

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Message-ID: <20151218093432.GA10581@intel.com>
Date:	Fri, 18 Dec 2015 11:34:32 +0200
From:	Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
To:	Jason Gunthorpe <jgunthorpe@...idianresearch.com>, g@...el.com
Cc:	tpmdd-devel@...ts.sourceforge.net, linux-kernel@...r.kernel.org,
	Martin Wilck <Martin.Wilck@...fujitsu.com>,
	Peter Huewe <peterhuewe@....de>,
	Uwe Kleine-König 
	<u.kleine-koenig@...gutronix.de>
Subject: Re: [PATCH v3 3/7] tpm_tis: Do not fall back to a hardcoded address
 for TPM2

On Thu, Dec 17, 2015 at 11:23:16AM -0700, Jason Gunthorpe wrote:
> If the ACPI tables do not declare a memory resource for the TPM2
> then do not just fall back to the x86 default base address.
> 
> Also be stricter when checking the ancillary TPM2 ACPI data and error
> out if any of this data is wrong rather than blindly assuming TPM1.
> 
> Fixes: 399235dc6e95 ("tpm, tpm_tis: fix tpm_tis ACPI detection issue with TPM 2.0")
> Signed-off-by: Jason Gunthorpe <jgunthorpe@...idianresearch.com>
> Tested-by: Wilck, Martin <martin.wilck@...fujitsu.com>
> Tested-by: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
> ---
>  drivers/char/tpm/tpm_tis.c | 48 +++++++++++++++++-----------------------------
>  1 file changed, 18 insertions(+), 30 deletions(-)
> 
> diff --git a/drivers/char/tpm/tpm_tis.c b/drivers/char/tpm/tpm_tis.c
> index fecd27b45fd1..b2b31f5418ca 100644
> --- a/drivers/char/tpm/tpm_tis.c
> +++ b/drivers/char/tpm/tpm_tis.c
> @@ -122,39 +122,11 @@ static inline int is_itpm(struct acpi_device *dev)
>  {
>  	return has_hid(dev, "INTC0102");
>  }
> -
> -static inline int is_fifo(struct acpi_device *dev)
> -{
> -	struct acpi_table_tpm2 *tbl;
> -	acpi_status st;
> -
> -	/* TPM 1.2 FIFO */
> -	if (!has_hid(dev, "MSFT0101"))
> -		return 1;
> -
> -	st = acpi_get_table(ACPI_SIG_TPM2, 1,
> -			    (struct acpi_table_header **) &tbl);
> -	if (ACPI_FAILURE(st)) {
> -		dev_err(&dev->dev, "failed to get TPM2 ACPI table\n");
> -		return 0;
> -	}
> -
> -	if (tbl->start_method != ACPI_TPM2_MEMORY_MAPPED)
> -		return 0;
> -
> -	/* TPM 2.0 FIFO */
> -	return 1;
> -}
>  #else
>  static inline int is_itpm(struct acpi_device *dev)
>  {
>  	return 0;
>  }
> -
> -static inline int is_fifo(struct acpi_device *dev)
> -{
> -	return 1;
> -}
>  #endif
>  
>  /* Before we attempt to access the TPM we must see that the valid bit is set.
> @@ -980,11 +952,21 @@ static int tpm_check_resource(struct acpi_resource *ares, void *data)
>  
>  static int tpm_tis_acpi_init(struct acpi_device *acpi_dev)
>  {
> +	struct acpi_table_tpm2 *tbl;
> +	acpi_status st;
>  	struct list_head resources;
> -	struct tpm_info tpm_info = tis_default_info;
> +	struct tpm_info tpm_info = {};
>  	int ret;
>  
> -	if (!is_fifo(acpi_dev))
> +	st = acpi_get_table(ACPI_SIG_TPM2, 1,
> +			    (struct acpi_table_header **) &tbl);
> +	if (ACPI_FAILURE(st) || tbl->header.length < sizeof(*tbl)) {
> +		dev_err(&acpi_dev->dev,
> +			FW_BUG "failed to get TPM2 ACPI table\n");
> +		return -EINVAL;
> +	}
> +
> +	if (tbl->start_method != ACPI_TPM2_MEMORY_MAPPED)
>  		return -ENODEV;
>  
>  	INIT_LIST_HEAD(&resources);
> @@ -996,6 +978,12 @@ static int tpm_tis_acpi_init(struct acpi_device *acpi_dev)
>  
>  	acpi_dev_free_resource_list(&resources);
>  
> +	if (tpm_info.start == 0 && tpm_info.len == 0) {
> +		dev_err(&acpi_dev->dev,
> +			FW_BUG "TPM2 ACPI table does not define a memory resource\n");
> +		return -EINVAL;
> +	}
> +

I guess this the only relevant change in this patch? You should propose
removal of is_fifo() as a separate patch if that makes sense. This patch
is now doing orthogonal things.

>  	if (is_itpm(acpi_dev))
>  		itpm = true;
>  
> -- 
> 2.1.4

/Jarkko
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