Date:   Thu,  9 Sep 2021 16:33:01 -0700
From:   Russ Weight <russell.h.weight@...el.com>
To:     mdf@...nel.org, linux-fpga@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     trix@...hat.com, lgoncalv@...hat.com, yilun.xu@...el.com,
        hao.wu@...el.com, matthew.gerlach@...el.com,
        Russ Weight <russell.h.weight@...el.com>
Subject: [PATCH v14 1/4] fpga: m10bmc-sec: create max10 bmc secure update driver

Create a sub driver for the FPGA Card BMC in order to support secure
updates.  This sub-driver will invoke an instance of the FPGA Image Load
class driver for the image load portion of the update.

This patch creates the MAX10 BMC Secure Update driver and provides sysfs
files for displaying the current root entry hashes for the FPGA static
region, the FPGA PR region, and the MAX10 BMC.

Signed-off-by: Russ Weight <russell.h.weight@...el.com>
Reviewed-by: Tom Rix <trix@...hat.com>
---
v14:
  - Changed symbol and text references to reflect the renaming of the
    Security Manager Class driver to FPGA Image Load.
v13:
  - Updated copyright to 2021
  - Updated ABI documentation date and kernel version
  - Call updated fpga_sec_mgr_register() and fpga_sec_mgr_unregister()
    functions instead of devm_fpga_sec_mgr_create() and
    devm_fpga_sec_mgr_register().
v12:
  - Updated Date and KernelVersion fields in ABI documentation
v11:
  - Added Reviewed-by tag
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 2/6, otherwise no change
v7:
  - Updated Date and KernelVersion in ABI documentation
v6:
  - Added WARN_ON() call for (sha_num_bytes / stride) to assert
    that the proper count is passed to regmap_bulk_read().
v5:
  - No change
v4:
  - Moved sysfs files for displaying the root entry hashes (REH)
    from the FPGA Security Manager class driver to here. The
    m10bmc_reh() and m10bmc_reh_size() functions are removed and
    the functionality from these functions is moved into a
    show_root_entry_hash() function for displaying the REHs.
  - Added ABI documentation for the new sysfs entries:
    sysfs-driver-intel-m10-bmc-secure
  - Updated the MAINTAINERS file to add the new ABI documentation
    file: sysfs-driver-intel-m10-bmc-secure
  - Removed unnecessary ret variable from m10bmc_secure_probe()
  - Incorporated new devm_fpga_sec_mgr_register() function into
    m10bmc_secure_probe() and removed the m10bmc_secure_remove()
    function.
v3:
  - Changed from "Intel FPGA Security Manager" to FPGA Security Manager"
  - 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.
  - Changed "_root_entry_hash" to "_reh", with a comment explaining
    what reh is.
v2:
  - Added drivers/fpga/intel-m10-bmc-secure.c file to MAINTAINERS.
  - Switched to GENMASK(31, 16) for a couple of mask definitions.
  - Moved MAX10 BMC address and function definitions to a separate
    patch.
  - Replaced small function-creation macros with explicit function
    declarations.
  - Removed ifpga_sec_mgr_init() and ifpga_sec_mgr_uinit() functions.
  - Adapted to changes in the Intel FPGA Security Manager by splitting
    the single call to ifpga_sec_mgr_register() into two function
    calls: devm_ifpga_sec_mgr_create() and ifpga_sec_mgr_register().
---
 .../testing/sysfs-driver-intel-m10-bmc-secure |  29 ++++
 MAINTAINERS                                   |   2 +
 drivers/fpga/Kconfig                          |  11 ++
 drivers/fpga/Makefile                         |   3 +
 drivers/fpga/intel-m10-bmc-secure.c           | 145 ++++++++++++++++++
 5 files changed, 190 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-driver-intel-m10-bmc-secure
 create mode 100644 drivers/fpga/intel-m10-bmc-secure.c

diff --git a/Documentation/ABI/testing/sysfs-driver-intel-m10-bmc-secure b/Documentation/ABI/testing/sysfs-driver-intel-m10-bmc-secure
new file mode 100644
index 000000000000..363403ce992d
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-driver-intel-m10-bmc-secure
@@ -0,0 +1,29 @@
+What:		/sys/bus/platform/drivers/intel-m10bmc-secure/.../security/sr_root_entry_hash
+Date:		Aug 2021
+KernelVersion:	5.15
+Contact:	Russ Weight <russell.h.weight@...el.com>
+Description:	Read only. Returns the root entry hash for the static
+		region if one is programmed, else it returns the
+		string: "hash not programmed".  This file is only
+		visible if the underlying device supports it.
+		Format: "0x%x".
+
+What:		/sys/bus/platform/drivers/intel-m10bmc-secure/.../security/pr_root_entry_hash
+Date:		Aug 2021
+KernelVersion:	5.15
+Contact:	Russ Weight <russell.h.weight@...el.com>
+Description:	Read only. Returns the root entry hash for the partial
+		reconfiguration region if one is programmed, else it
+		returns the string: "hash not programmed".  This file
+		is only visible if the underlying device supports it.
+		Format: "0x%x".
+
+What:		/sys/bus/platform/drivers/intel-m10bmc-secure/.../security/bmc_root_entry_hash
+Date:		Aug 2021
+KernelVersion:	5.15
+Contact:	Russ Weight <russell.h.weight@...el.com>
+Description:	Read only. Returns the root entry hash for the BMC image
+		if one is programmed, else it returns the string:
+		"hash not programmed".  This file is only visible if the
+		underlying device supports it.
+		Format: "0x%x".
diff --git a/MAINTAINERS b/MAINTAINERS
index e3fbc1bde9bc..cf93835b4775 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -7363,8 +7363,10 @@ M:	Russ Weight <russell.h.weight@...el.com>
 L:	linux-fpga@...r.kernel.org
 S:	Maintained
 F:	Documentation/ABI/testing/sysfs-class-fpga-image-load
+F:	Documentation/ABI/testing/sysfs-driver-intel-m10-bmc-secure
 F:	Documentation/fpga/fpga-image-load.rst
 F:	drivers/fpga/fpga-image-load.c
+F:	drivers/fpga/intel-m10-bmc-secure.c
 F:	include/linux/fpga/fpga-image-load.h
 F:	include/uapi/linux/fpga-image-load.h
 
diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig
index c12a14e62fff..9d25b1ec03cd 100644
--- a/drivers/fpga/Kconfig
+++ b/drivers/fpga/Kconfig
@@ -253,4 +253,15 @@ config FPGA_IMAGE_LOAD
 	  and/or the device itself to authenticate and disposition the
 	  image data.
 
+config FPGA_M10_BMC_SECURE
+	tristate "Intel MAX10 BMC Secure Update driver"
+	depends on MFD_INTEL_M10_BMC && FPGA_IMAGE_LOAD
+	help
+	  Secure update support for the Intel MAX10 board management
+	  controller.
+
+	  This is a subdriver of the Intel MAX10 board management controller
+	  (BMC) and provides support for secure updates for the BMC image,
+	  the FPGA image, the Root Entry Hashes, etc.
+
 endif # FPGA
diff --git a/drivers/fpga/Makefile b/drivers/fpga/Makefile
index adf228ee4f5e..8d4c1869ac4c 100644
--- a/drivers/fpga/Makefile
+++ b/drivers/fpga/Makefile
@@ -25,6 +25,9 @@ obj-$(CONFIG_ALTERA_PR_IP_CORE_PLAT)    += altera-pr-ip-core-plat.o
 # FPGA Image Load Framework
 obj-$(CONFIG_FPGA_IMAGE_LOAD)		+= fpga-image-load.o
 
+# FPGA Secure Update Drivers
+obj-$(CONFIG_FPGA_M10_BMC_SECURE)	+= intel-m10-bmc-secure.o
+
 # FPGA Bridge Drivers
 obj-$(CONFIG_FPGA_BRIDGE)		+= fpga-bridge.o
 obj-$(CONFIG_SOCFPGA_FPGA_BRIDGE)	+= altera-hps2fpga.o altera-fpga2sdram.o
diff --git a/drivers/fpga/intel-m10-bmc-secure.c b/drivers/fpga/intel-m10-bmc-secure.c
new file mode 100644
index 000000000000..03fc571f40f2
--- /dev/null
+++ b/drivers/fpga/intel-m10-bmc-secure.c
@@ -0,0 +1,145 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Intel Max10 Board Management Controller Secure Update Driver
+ *
+ * Copyright (C) 2019-2021 Intel Corporation. All rights reserved.
+ *
+ */
+#include <linux/bitfield.h>
+#include <linux/device.h>
+#include <linux/fpga/fpga-image-load.h>
+#include <linux/mfd/intel-m10-bmc.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+struct m10bmc_sec {
+	struct device *dev;
+	struct intel_m10bmc *m10bmc;
+	struct fpga_image_load *imgld;
+};
+
+/* Root Entry Hash (REH) support */
+#define REH_SHA256_SIZE		32
+#define REH_SHA384_SIZE		48
+#define REH_MAGIC		GENMASK(15, 0)
+#define REH_SHA_NUM_BYTES	GENMASK(31, 16)
+
+static ssize_t
+show_root_entry_hash(struct device *dev, u32 exp_magic,
+		     u32 prog_addr, u32 reh_addr, char *buf)
+{
+	struct m10bmc_sec *sec = dev_get_drvdata(dev);
+	unsigned int stride = regmap_get_reg_stride(sec->m10bmc->regmap);
+	int sha_num_bytes, i, cnt, ret;
+	u8 hash[REH_SHA384_SIZE];
+	u32 magic;
+
+	ret = m10bmc_raw_read(sec->m10bmc, prog_addr, &magic);
+	if (ret)
+		return ret;
+
+	dev_dbg(dev, "%s magic 0x%08x\n", __func__, magic);
+
+	if (FIELD_GET(REH_MAGIC, magic) != exp_magic)
+		return sysfs_emit(buf, "hash not programmed\n");
+
+	sha_num_bytes = FIELD_GET(REH_SHA_NUM_BYTES, magic) / 8;
+	if (sha_num_bytes != REH_SHA256_SIZE &&
+	    sha_num_bytes != REH_SHA384_SIZE)   {
+		dev_err(sec->dev, "%s bad sha num bytes %d\n", __func__,
+			sha_num_bytes);
+		return -EINVAL;
+	}
+
+	WARN_ON(sha_num_bytes % stride);
+	ret = regmap_bulk_read(sec->m10bmc->regmap, reh_addr,
+			       hash, sha_num_bytes / stride);
+	if (ret) {
+		dev_err(dev, "failed to read root entry hash: %x cnt %x: %d\n",
+			reh_addr, sha_num_bytes / stride, ret);
+		return ret;
+	}
+
+	cnt = sprintf(buf, "0x");
+	for (i = 0; i < sha_num_bytes; i++)
+		cnt += sprintf(buf + cnt, "%02x", hash[i]);
+	cnt += sprintf(buf + cnt, "\n");
+
+	return cnt;
+}
+
+#define DEVICE_ATTR_SEC_REH_RO(_name, _magic, _prog_addr, _reh_addr) \
+static ssize_t _name##_root_entry_hash_show(struct device *dev, \
+					    struct device_attribute *attr, \
+					    char *buf) \
+{ return show_root_entry_hash(dev, _magic, _prog_addr, _reh_addr, buf); } \
+static DEVICE_ATTR_RO(_name##_root_entry_hash)
+
+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);
+
+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,
+	NULL,
+};
+
+static struct attribute_group m10bmc_security_attr_group = {
+	.name = "security",
+	.attrs = m10bmc_security_attrs,
+};
+
+static const struct attribute_group *m10bmc_sec_attr_groups[] = {
+	&m10bmc_security_attr_group,
+	NULL,
+};
+
+static const struct fpga_image_load_ops m10bmc_lops = { };
+
+static int m10bmc_secure_probe(struct platform_device *pdev)
+{
+	struct fpga_image_load *imgld;
+	struct m10bmc_sec *sec;
+
+	sec = devm_kzalloc(&pdev->dev, sizeof(*sec), GFP_KERNEL);
+	if (!sec)
+		return -ENOMEM;
+
+	sec->dev = &pdev->dev;
+	sec->m10bmc = dev_get_drvdata(pdev->dev.parent);
+	dev_set_drvdata(&pdev->dev, sec);
+
+	imgld = fpga_image_load_register(sec->dev, &m10bmc_lops, sec);
+	if (IS_ERR(imgld)) {
+		dev_err(sec->dev, "FPGA Image Load driver failed to start\n");
+		return PTR_ERR(imgld);
+	}
+
+	sec->imgld = imgld;
+	return 0;
+}
+
+static int m10bmc_secure_remove(struct platform_device *pdev)
+{
+	struct m10bmc_sec *sec = dev_get_drvdata(&pdev->dev);
+
+	fpga_image_load_unregister(sec->imgld);
+	return 0;
+}
+
+static struct platform_driver intel_m10bmc_secure_driver = {
+	.probe = m10bmc_secure_probe,
+	.remove = m10bmc_secure_remove,
+	.driver = {
+		.name = "n3000bmc-secure",
+		.dev_groups = m10bmc_sec_attr_groups,
+	},
+};
+module_platform_driver(intel_m10bmc_secure_driver);
+
+MODULE_ALIAS("platform:n3000bmc-secure");
+MODULE_AUTHOR("Intel Corporation");
+MODULE_DESCRIPTION("Intel MAX10 BMC Secure Update");
+MODULE_LICENSE("GPL v2");
-- 
2.25.1

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