Re: [PATCH v4 4/6] fpga: m10bmc-sec: expose max10 canceled keys in sysfs

[Russ Weight]

On 11/5/20 6:23 PM, Russ Weight wrote:
> Extend the MAX10 BMC Secure Update driver to provide sysfs
> files to expose the canceled code signing key (CSK) bit
> vectors. These use the standard bitmap list format
> (e.g. 1,2-6,9).
>
> Signed-off-by: Russ Weight <russell.h.weight@xxxxxxxxx>
> Reviewed-by: Tom Rix <trix@xxxxxxxxxx>
> ---
> v4:
>   - Moved sysfs files for displaying the code-signing-key (CSK)
>     cancellation vectors from the FPGA Security Manger class driver
>     to here. The m10bmc_csk_vector() and m10bmc_csk_cancel_nbits()
>     functions are removed and the functionality from these functions
>     is moved into a show_canceled_csk() function for for displaying
>     the CSK vectors.
FYI: although the show_canceled_csk() function mostly consists
of a reorganization of existing code, there are a couple of significant
changes:
(1) The bit mask data is all on the stack now, instead of the heap
(2) In order to resolve a warning from the sparse tool, I have declared
    an additional array: csk_le32[]
>   - Added ABI documentation for new sysfs entries
> v3:
>   - Changed: iops -> sops, imgr -> smgr, IFPGA_ -> FPGA_, ifpga_ to fpga_
>   - Changed "MAX10 BMC Secure Engine driver" to "MAX10 BMC Secure Update
>     driver"
>   - Removed wrapper functions (m10bmc_raw_*, m10bmc_sys_*). The
>     underlying functions are now called directly.
>   - Renamed get_csk_vector() to m10bmc_csk_vector()
> v2:
>   - Replaced small function-creation macros for explicit function
>     declarations.
>   - Fixed get_csk_vector() function to properly apply the stride
>     variable in calls to m10bmc_raw_bulk_read()
>   - Added m10bmc_ prefix to functions in m10bmc_iops structure
> ---
>  .../testing/sysfs-driver-intel-m10-bmc-secure | 24 ++++++++++
>  drivers/fpga/intel-m10-bmc-secure.c           | 46 +++++++++++++++++++
>  2 files changed, 70 insertions(+)
>
> diff --git a/Documentation/ABI/testing/sysfs-driver-intel-m10-bmc-secure b/Documentation/ABI/testing/sysfs-driver-intel-m10-bmc-secure
> index 14025b72e5ee..1517bd0400d5 100644
> --- a/Documentation/ABI/testing/sysfs-driver-intel-m10-bmc-secure
> +++ b/Documentation/ABI/testing/sysfs-driver-intel-m10-bmc-secure
> @@ -28,6 +28,30 @@ Description:	Read only. Returns the root entry hash for the BMC image
>  		underlying device supports it.
>  		Format: "0x%x".
>  
> +What:		/sys/bus/platform/devices/n3000bmc-secure.*.auto/security/sr_canceled_csks
> +Date:		Oct 2020
> +KernelVersion:  5.11
> +Contact:	Russ Weight <russell.h.weight@xxxxxxxxx>
> +Description:	Read only. Returns a list of indices for canceled code
> +		signing keys for the static region. The standard bitmap
> +		list format is used (e.g. "1,2-6,9").
> +
> +What:		/sys/bus/platform/devices/n3000bmc-secure.*.auto/security/pr_canceled_csks
> +Date:		Oct 2020
> +KernelVersion:  5.11
> +Contact:	Russ Weight <russell.h.weight@xxxxxxxxx>
> +Description:	Read only. Returns a list of indices for canceled code
> +		signing keys for the partial reconfiguration region. The
> +		standard bitmap list format is used (e.g. "1,2-6,9").
> +
> +What:		/sys/bus/platform/devices/n3000bmc-secure.*.auto/security/bmc_canceled_csks
> +Date:		Oct 2020
> +KernelVersion:  5.11
> +Contact:	Russ Weight <russell.h.weight@xxxxxxxxx>
> +Description:	Read only. Returns a list of indices for canceled code
> +		signing keys for the BMC.  The standard bitmap list format
> +		is used (e.g. "1,2-6,9").
> +
>  What:		/sys/bus/platform/devices/n3000bmc-secure.*.auto/security/user_flash_count
>  Date:		Oct 2020
>  KernelVersion:  5.11
> diff --git a/drivers/fpga/intel-m10-bmc-secure.c b/drivers/fpga/intel-m10-bmc-secure.c
> index a6747735798e..806ef93b027d 100644
> --- a/drivers/fpga/intel-m10-bmc-secure.c
> +++ b/drivers/fpga/intel-m10-bmc-secure.c
> @@ -78,6 +78,49 @@ DEVICE_ATTR_SEC_REH_RO(bmc, BMC_PROG_MAGIC, BMC_PROG_ADDR, BMC_REH_ADDR);
>  DEVICE_ATTR_SEC_REH_RO(sr, SR_PROG_MAGIC, SR_PROG_ADDR, SR_REH_ADDR);
>  DEVICE_ATTR_SEC_REH_RO(pr, PR_PROG_MAGIC, PR_PROG_ADDR, PR_REH_ADDR);
>  
> +#define CSK_BIT_LEN		128U
> +#define CSK_32ARRAY_SIZE	DIV_ROUND_UP(CSK_BIT_LEN, 32)
> +
> +static ssize_t
> +show_canceled_csk(struct device *dev, u32 addr, char *buf)
> +{
> +	unsigned int i, stride, size = CSK_32ARRAY_SIZE * sizeof(u32);
> +	struct m10bmc_sec *sec = dev_get_drvdata(dev);
> +	DECLARE_BITMAP(csk_map, CSK_BIT_LEN);
> +	__le32 csk_le32[CSK_32ARRAY_SIZE];
> +	u32 csk32[CSK_32ARRAY_SIZE];
> +	int ret;
> +
> +	stride = regmap_get_reg_stride(sec->m10bmc->regmap);
> +
> +	ret = regmap_bulk_read(sec->m10bmc->regmap, addr, csk_le32, size / stride);
> +	if (ret) {
> +		dev_err(sec->dev, "failed to read CSK vector: %x cnt %x: %d\n",
> +			addr, size / stride, ret);
> +		return ret;
> +	}
> +
> +	for (i = 0; i < CSK_32ARRAY_SIZE; i++)
> +		csk32[i] = le32_to_cpu(((csk_le32[i])));
> +
> +	bitmap_from_arr32(csk_map, csk32, CSK_BIT_LEN);
> +	bitmap_complement(csk_map, csk_map, CSK_BIT_LEN);
> +	return bitmap_print_to_pagebuf(1, buf, csk_map, CSK_BIT_LEN);
> +}
> +
> +#define DEVICE_ATTR_SEC_CSK_RO(_name, _addr) \
> +static ssize_t _name##_canceled_csks_show(struct device *dev, \
> +					  struct device_attribute *attr, \
> +					  char *buf) \
> +{ return show_canceled_csk(dev, _addr, buf); } \
> +static DEVICE_ATTR_RO(_name##_canceled_csks)
> +
> +#define CSK_VEC_OFFSET 0x34
> +
> +DEVICE_ATTR_SEC_CSK_RO(bmc, BMC_PROG_ADDR + CSK_VEC_OFFSET);
> +DEVICE_ATTR_SEC_CSK_RO(sr, SR_PROG_ADDR + CSK_VEC_OFFSET);
> +DEVICE_ATTR_SEC_CSK_RO(pr, PR_PROG_ADDR + CSK_VEC_OFFSET);
> +
>  #define FLASH_COUNT_SIZE 4096	/* count stored in inverted bit vector */
>  
>  static ssize_t user_flash_count_show(struct device *dev,
> @@ -115,6 +158,9 @@ static struct attribute *m10bmc_security_attrs[] = {
>  	&dev_attr_bmc_root_entry_hash.attr,
>  	&dev_attr_sr_root_entry_hash.attr,
>  	&dev_attr_pr_root_entry_hash.attr,
> +	&dev_attr_sr_canceled_csks.attr,
> +	&dev_attr_pr_canceled_csks.attr,
> +	&dev_attr_bmc_canceled_csks.attr,
>  	NULL,
>  };
>