[PATCH v17 4/5] fpga: cardbmc-sec: expose canceled keys in sysfs

From: Russ Weight
Date: Thu Apr 28 2022 - 19:37:56 EST

Extend the FPGA Card 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>
---
v17:
- Update the Date and KernelVersion for the ABI documentation to Jul 2022
and 5.19 respectively.
- Change "m10bmc" in symbol names to "cardbmc" to reflect the fact that the
future devices will not necessarily use the MAX10.
v16:
- No Change
v15:
- Updated the Dates and KernelVersions in the ABI documentation
v14:
- No changes
v13:
- Updated ABI documentation date and kernel version
v12:
- Updated Date and KernelVersion fields in ABI documentation
v11:
- No change
v10:
- Changed the path expressions in the sysfs documentation to
replace the n3000 reference with something more generic to
accomodate other devices that use the same driver.
v9:
- Rebased to 5.12-rc2 next
- Updated Date and KernelVersion in ABI documentation
v8:
- Previously patch 4/6, otherwise no change
v7:
- Updated Date and KernelVersion in ABI documentation
v6:
- Added WARN_ON() call for (size / stride) to ensure
that the proper count is passed to regmap_bulk_read().
v5:
- No change
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.
- 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
---
.../sysfs-driver-intel-cardbmc-sec-update | 24 ++++++++++
drivers/fpga/intel-cardbmc-sec-update.c | 48 +++++++++++++++++++
2 files changed, 72 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-driver-intel-cardbmc-sec-update b/Documentation/ABI/testing/sysfs-driver-intel-cardbmc-sec-update
index 80279a3e36a5..7fe0d03c3175 100644
--- a/Documentation/ABI/testing/sysfs-driver-intel-cardbmc-sec-update
+++ b/Documentation/ABI/testing/sysfs-driver-intel-cardbmc-sec-update
@@ -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/drivers/intel-cardbmc-sec-update/.../security/sr_canceled_csks
+Date: Jul 2022
+KernelVersion: 5.19
+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/drivers/intel-cardbmc-sec-update/.../security/pr_canceled_csks
+Date: Jul 2022
+KernelVersion: 5.19
+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/drivers/intel-cardbmc-sec-update/.../security/bmc_canceled_csks
+Date: Jul 2022
+KernelVersion: 5.19
+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/drivers/intel-cardbmc-sec-update/.../security/flash_count
Date: Jul 2022
KernelVersion: 5.19
diff --git a/drivers/fpga/intel-cardbmc-sec-update.c b/drivers/fpga/intel-cardbmc-sec-update.c
index 12c8ebdf4c14..0b268d925e0a 100644
--- a/drivers/fpga/intel-cardbmc-sec-update.c
+++ b/drivers/fpga/intel-cardbmc-sec-update.c
@@ -84,6 +84,51 @@ 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 bmc_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);
+
+ WARN_ON(size % stride);
+ 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 as inverted bit vector */

static ssize_t flash_count_show(struct device *dev,
@@ -124,6 +169,9 @@ static struct attribute *bmc_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,
};

--
2.25.1