[PATCH 1/2] fpga: Add flag to indicate bitstream needs decrypting

[PATCH 1/2] fpga: Add flag to indicate bitstream needs decrypting

[mdf]

From: Moritz Fischer <moritz.fischer@ettus.com>

Add a flag that is passed to the write_init() callback, indicating
that the bitstream is encrypted.

The low-level driver will deal with the flag, or return an error,
if encrypted bitstreams are not supported.

Signed-off-by: Moritz Fischer <moritz.fischer@ettus.com>
Cc: Alan Tull <atull@kernel.org>
Cc: Michal Simek <michal.simek@xilinx.com>
Cc: Sören Brinkmann <soren.brinkmann@xilinx.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-fpga@vger.kernel.org
---
 include/linux/fpga/fpga-mgr.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/include/linux/fpga/fpga-mgr.h b/include/linux/fpga/fpga-mgr.h
index 57beb5d..1355d8a 100644
--- a/include/linux/fpga/fpga-mgr.h
+++ b/include/linux/fpga/fpga-mgr.h
@@ -70,6 +70,7 @@ enum fpga_mgr_states {
  */
 #define FPGA_MGR_PARTIAL_RECONFIG	BIT(0)
 #define FPGA_MGR_EXTERNAL_CONFIG	BIT(1)
+#define FPGA_MGR_DECRYPT_BITSTREAM	BIT(2)
 
 /**
  * struct fpga_image_info - information specific to a FPGA image
-- 
2.7.4

[PATCH 2/2] fpga: zynq: Add support for encrypted bitstreams

[mdf]

From: Moritz Fischer <moritz.fischer@ettus.com>

Add support for encrypted bitstreams. For this to work the system
must be booted in secure mode.

In order for on-the-fly decryption to work, the PCAP clock rate
needs to be lowered via the PCAP_RATE_EN bit.

Signed-off-by: Moritz Fischer <moritz.fischer@ettus.com>
Cc: Alan Tull <atull@kernel.org>
Cc: Michal Simek <michal.simek@xilinx.com>
Cc: Sören Brinkmann <soren.brinkmann@xilinx.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-fpga@vger.kernel.org
---
 drivers/fpga/zynq-fpga.c | 28 +++++++++++++++++++++++++---
 1 file changed, 25 insertions(+), 3 deletions(-)

diff --git a/drivers/fpga/zynq-fpga.c b/drivers/fpga/zynq-fpga.c
index cb3caf5..52dabfc 100644
--- a/drivers/fpga/zynq-fpga.c
+++ b/drivers/fpga/zynq-fpga.c
@@ -72,6 +72,10 @@
 #define CTRL_PCAP_PR_MASK		BIT(27)
 /* Enable PCAP */
 #define CTRL_PCAP_MODE_MASK		BIT(26)
+/* Lower rate to allow decrypt on the fly */
+#define CTRL_PCAP_RATE_EN_MASK		BIT(25)
+/* System booted in secure mode */
+#define CTRL_SEC_EN_MASK		BIT(7)
 
 /* Miscellaneous Control Register bit definitions */
 /* Internal PCAP loopback */
@@ -264,6 +268,17 @@ static int zynq_fpga_ops_write_init(struct fpga_manager *mgr,
 	if (err)
 		return err;
 
+	/* check if bitstream is encrypted & and system's still secure */
+	if (info->flags & FPGA_MGR_DECRYPT_BITSTREAM) {
+		ctrl = zynq_fpga_read(priv, CTRL_OFFSET);
+		if (!(ctrl & CTRL_SEC_EN_MASK)) {
+			dev_err(&mgr->dev,
+				"System not secure, can't use crypted bitstreams\n");
+			err = -EINVAL;
+			goto out_err;
+		}
+	}
+
 	/* don't globally reset PL if we're doing partial reconfig */
 	if (!(info->flags & FPGA_MGR_PARTIAL_RECONFIG)) {
 		if (!zynq_fpga_has_sync(buf, count)) {
@@ -335,12 +350,19 @@ static int zynq_fpga_ops_write_init(struct fpga_manager *mgr,
 
 	/* set configuration register with following options:
 	 * - enable PCAP interface
-	 * - set throughput for maximum speed
+	 * - set throughput for maximum speed (if bistream not crypted)
 	 * - set CPU in user mode
 	 */
 	ctrl = zynq_fpga_read(priv, CTRL_OFFSET);
-	zynq_fpga_write(priv, CTRL_OFFSET,
-			(CTRL_PCAP_PR_MASK | CTRL_PCAP_MODE_MASK | ctrl));
+	if (info->flags & FPGA_MGR_DECRYPT_BITSTREAM)
+		zynq_fpga_write(priv, CTRL_OFFSET,
+				(CTRL_PCAP_PR_MASK | CTRL_PCAP_MODE_MASK
+				 | CTRL_PCAP_RATE_EN_MASK | ctrl));
+	else
+		zynq_fpga_write(priv, CTRL_OFFSET,
+				(CTRL_PCAP_PR_MASK | CTRL_PCAP_MODE_MASK
+				 | ctrl));
+
 
 	/* We expect that the command queue is empty right now. */
 	status = zynq_fpga_read(priv, STATUS_OFFSET);
-- 
2.7.4

Re: [PATCH 1/2] fpga: Add flag to indicate bitstream needs decrypting

[Michal Simek]

On 15.2.2017 01:31, mdf@kernel.org wrote:
> From: Moritz Fischer <moritz.fischer@ettus.com>
> 
> Add a flag that is passed to the write_init() callback, indicating
> that the bitstream is encrypted.
> 
> The low-level driver will deal with the flag, or return an error,
> if encrypted bitstreams are not supported.
> 
> Signed-off-by: Moritz Fischer <moritz.fischer@ettus.com>
> Cc: Alan Tull <atull@kernel.org>
> Cc: Michal Simek <michal.simek@xilinx.com>
> Cc: Sören Brinkmann <soren.brinkmann@xilinx.com>
> Cc: linux-kernel@vger.kernel.org
> Cc: linux-fpga@vger.kernel.org
> ---
>  include/linux/fpga/fpga-mgr.h | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/include/linux/fpga/fpga-mgr.h b/include/linux/fpga/fpga-mgr.h
> index 57beb5d..1355d8a 100644
> --- a/include/linux/fpga/fpga-mgr.h
> +++ b/include/linux/fpga/fpga-mgr.h
> @@ -70,6 +70,7 @@ enum fpga_mgr_states {
>   */
>  #define FPGA_MGR_PARTIAL_RECONFIG	BIT(0)
>  #define FPGA_MGR_EXTERNAL_CONFIG	BIT(1)
> +#define FPGA_MGR_DECRYPT_BITSTREAM	BIT(2)
>  
>  /**
>   * struct fpga_image_info - information specific to a FPGA image
> 

Isn't it better to state that bitstream is encrypted
instead of saying that bitstream requires decryption?

Your second patch is saying add support for encrypted bitstreams.

M

Re: [PATCH 1/2] fpga: Add flag to indicate bitstream needs decrypting

[Michal Simek]

On 15.2.2017 01:31, mdf@kernel.org wrote:
> From: Moritz Fischer <moritz.fischer@ettus.com>
> 
> Add a flag that is passed to the write_init() callback, indicating
> that the bitstream is encrypted.
> 
> The low-level driver will deal with the flag, or return an error,
> if encrypted bitstreams are not supported.
> 
> Signed-off-by: Moritz Fischer <moritz.fischer@ettus.com>
> Cc: Alan Tull <atull@kernel.org>
> Cc: Michal Simek <michal.simek@xilinx.com>
> Cc: Sören Brinkmann <soren.brinkmann@xilinx.com>
> Cc: linux-kernel@vger.kernel.org
> Cc: linux-fpga@vger.kernel.org
> ---
>  include/linux/fpga/fpga-mgr.h | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/include/linux/fpga/fpga-mgr.h b/include/linux/fpga/fpga-mgr.h
> index 57beb5d..1355d8a 100644
> --- a/include/linux/fpga/fpga-mgr.h
> +++ b/include/linux/fpga/fpga-mgr.h
> @@ -70,6 +70,7 @@ enum fpga_mgr_states {
>   */
>  #define FPGA_MGR_PARTIAL_RECONFIG	BIT(0)
>  #define FPGA_MGR_EXTERNAL_CONFIG	BIT(1)
> +#define FPGA_MGR_DECRYPT_BITSTREAM	BIT(2)
>  
>  /**
>   * struct fpga_image_info - information specific to a FPGA image
> 

Isn't it better to state that bitstream is encrypted
instead of saying that bitstream requires decryption?

Your second patch is saying add support for encrypted bitstreams.

M

Re: [PATCH 1/2] fpga: Add flag to indicate bitstream needs decrypting

[Alan Tull]

On Wed, Feb 15, 2017 at 9:03 AM, Michal Simek <michal.simek@xilinx.com> wrote:
> On 15.2.2017 01:31, mdf@kernel.org wrote:
>> From: Moritz Fischer <moritz.fischer@ettus.com>
>>
>> Add a flag that is passed to the write_init() callback, indicating
>> that the bitstream is encrypted.
>>
>> The low-level driver will deal with the flag, or return an error,
>> if encrypted bitstreams are not supported.
>>
>> Signed-off-by: Moritz Fischer <moritz.fischer@ettus.com>
>> Cc: Alan Tull <atull@kernel.org>
>> Cc: Michal Simek <michal.simek@xilinx.com>
>> Cc: Sören Brinkmann <soren.brinkmann@xilinx.com>
>> Cc: linux-kernel@vger.kernel.org
>> Cc: linux-fpga@vger.kernel.org
>> ---
>>  include/linux/fpga/fpga-mgr.h | 1 +
>>  1 file changed, 1 insertion(+)
>>
>> diff --git a/include/linux/fpga/fpga-mgr.h b/include/linux/fpga/fpga-mgr.h
>> index 57beb5d..1355d8a 100644
>> --- a/include/linux/fpga/fpga-mgr.h
>> +++ b/include/linux/fpga/fpga-mgr.h
>> @@ -70,6 +70,7 @@ enum fpga_mgr_states {
>>   */
>>  #define FPGA_MGR_PARTIAL_RECONFIG    BIT(0)
>>  #define FPGA_MGR_EXTERNAL_CONFIG     BIT(1)
>> +#define FPGA_MGR_DECRYPT_BITSTREAM   BIT(2)
>>
>>  /**
>>   * struct fpga_image_info - information specific to a FPGA image
>>
>
> Isn't it better to state that bitstream is encrypted
> instead of saying that bitstream requires decryption?

Such as FPGA_MGR_ENCRYPTED_BITSTREAM  ?

Also please consider adding a DT property such that the FPGA region
code will set this flag similar to how the DTO sets up other FPGA
image info.

Alan

>
> Your second patch is saying add support for encrypted bitstreams.
>
> M
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-fpga" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [PATCH 1/2] fpga: Add flag to indicate bitstream needs decrypting

[Moritz Fischer]

On Wed, Feb 15, 2017 at 5:30 PM, Alan Tull <atull@kernel.org> wrote:
> On Wed, Feb 15, 2017 at 9:03 AM, Michal Simek <michal.simek@xilinx.com> wrote:

>>>  #define FPGA_MGR_PARTIAL_RECONFIG    BIT(0)
>>>  #define FPGA_MGR_EXTERNAL_CONFIG     BIT(1)
>>> +#define FPGA_MGR_DECRYPT_BITSTREAM   BIT(2)
>>>
>>>  /**
>>>   * struct fpga_image_info - information specific to a FPGA image
>>>
>>
>> Isn't it better to state that bitstream is encrypted
>> instead of saying that bitstream requires decryption?
>
> Such as FPGA_MGR_ENCRYPTED_BITSTREAM  ?

Yeah, can do. This was basically a 'redo' of my earlier 'capability' based
patchset. There it made more sense to have a 'can decrypt' capability.

> Also please consider adding a DT property such that the FPGA region
> code will set this flag similar to how the DTO sets up other FPGA
> image info.

Yeah, had that on my list. Can add that to v3.

Cheers,

Moritz

Re: [PATCH 1/2] fpga: Add flag to indicate bitstream needs decrypting

[Michal Simek]

On 15.2.2017 19:02, Moritz Fischer wrote:
> On Wed, Feb 15, 2017 at 5:30 PM, Alan Tull <atull@kernel.org> wrote:
>> On Wed, Feb 15, 2017 at 9:03 AM, Michal Simek <michal.simek@xilinx.com> wrote:
> 
>>>>  #define FPGA_MGR_PARTIAL_RECONFIG    BIT(0)
>>>>  #define FPGA_MGR_EXTERNAL_CONFIG     BIT(1)
>>>> +#define FPGA_MGR_DECRYPT_BITSTREAM   BIT(2)
>>>>
>>>>  /**
>>>>   * struct fpga_image_info - information specific to a FPGA image
>>>>
>>>
>>> Isn't it better to state that bitstream is encrypted
>>> instead of saying that bitstream requires decryption?
>>
>> Such as FPGA_MGR_ENCRYPTED_BITSTREAM  ?
> 
> Yeah, can do. This was basically a 'redo' of my earlier 'capability' based
> patchset. There it made more sense to have a 'can decrypt' capability.

Just keep in your mind that there are use cases where you also need to
pass keys.

Thanks,
Michal