On Tue, Apr 19, 2016 at 12:54:18PM +0300, Jarkko Sakkinen wrote:
> On my Lenovo x250 the following situation occurs:
> 
> [18697.813871] tpm_crb MSFT0101:00: can't request region for resource
> [mem 0xacdff080-0xacdfffff]
> 
> The mapping of the control area overlaps the mapping of the command
> buffer. The control area is mapped over page, which is not right. It
> should mapped over sizeof(struct crb_control_area).
> 
> Fixing this issue unmasks another issue. Command and response buffers
> can overlap and they do interleave on this machine. According to the PTP
> specification the overlapping means that they are mapped to the same
> buffer.
> 
> The commit has been also on a Haswell NUC where things worked before
> applying this fix so that the both code paths for response buffer
> initialization are tested.
> 
> Cc: sta...@vger.kernel.org
> Fixes: 1bd047be37d9 ("tpm_crb: Use devm_ioremap_resource")
> Signed-off-by: Jarkko Sakkinen <jarkko.sakki...@linux.intel.com>

Forgot to add --subject-prefix="PATCH v2", sorry.

/Jarkko

> ---
>  drivers/char/tpm/tpm_crb.c | 39 ++++++++++++++++++++++++++++-----------
>  1 file changed, 28 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
> index 733cd0e..5afe684 100644
> --- a/drivers/char/tpm/tpm_crb.c
> +++ b/drivers/char/tpm/tpm_crb.c
> @@ -259,7 +259,10 @@ static int crb_map_io(struct acpi_device *device, struct 
> crb_priv *priv,
>       struct list_head resources;
>       struct resource io_res;
>       struct device *dev = &device->dev;
> -     u64 pa;
> +     u64 cmd_pa;
> +     u32 cmd_size;
> +     u64 rsp_pa;
> +     u32 rsp_size;
>       int ret;
>  
>       INIT_LIST_HEAD(&resources);
> @@ -280,22 +283,36 @@ static int crb_map_io(struct acpi_device *device, 
> struct crb_priv *priv,
>               return PTR_ERR(priv->iobase);
>  
>       priv->cca = crb_map_res(dev, priv, &io_res, buf->control_address,
> -                             0x1000);
> +                             sizeof(struct crb_control_area));
>       if (IS_ERR(priv->cca))
>               return PTR_ERR(priv->cca);
>  
> -     pa = ((u64) ioread32(&priv->cca->cmd_pa_high) << 32) |
> -           (u64) ioread32(&priv->cca->cmd_pa_low);
> -     priv->cmd = crb_map_res(dev, priv, &io_res, pa,
> -                             ioread32(&priv->cca->cmd_size));
> +     cmd_pa = ((u64) ioread32(&priv->cca->cmd_pa_high) << 32) |
> +               (u64) ioread32(&priv->cca->cmd_pa_low);
> +     cmd_size = ioread32(&priv->cca->cmd_size);
> +     priv->cmd = crb_map_res(dev, priv, &io_res, cmd_pa, cmd_size);
>       if (IS_ERR(priv->cmd))
>               return PTR_ERR(priv->cmd);
>  
> -     memcpy_fromio(&pa, &priv->cca->rsp_pa, 8);
> -     pa = le64_to_cpu(pa);
> -     priv->rsp = crb_map_res(dev, priv, &io_res, pa,
> -                             ioread32(&priv->cca->rsp_size));
> -     return PTR_ERR_OR_ZERO(priv->rsp);
> +     memcpy_fromio(&rsp_pa, &priv->cca->rsp_pa, 8);
> +     rsp_pa = le64_to_cpu(rsp_pa);
> +     rsp_size = ioread32(&priv->cca->rsp_size);
> +
> +     if (cmd_pa != rsp_pa) {
> +             priv->rsp = crb_map_res(dev, priv, &io_res, rsp_pa, rsp_size);
> +             return PTR_ERR_OR_ZERO(priv->rsp);
> +     }
> +
> +     /* According to the PTP specification, overlapping command and response
> +      * buffer sizes must be identical.
> +      */
> +     if (cmd_size != rsp_size) {
> +             dev_err(dev, FW_BUG "overlapping command and response buffer 
> sizes are not identical");
> +             return -EINVAL;
> +     }
> +
> +     priv->rsp = priv->cmd;
> +     return 0;
>  }
>  
>  static int crb_acpi_add(struct acpi_device *device)
> -- 
> 2.7.4
> 

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