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SubjectRe: [PATCH v5 2/6] fpga: m10bmc-sec: create max10 bmc secure update driver
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On 11/13/20 4:55 PM, Russ Weight wrote:
> Create a platform driver that can be invoked as a sub
> driver for the Intel MAX10 BMC in order to support
> secure updates. This sub-driver will invoke an
> instance of the FPGA Security Manager class driver
> in order to expose sysfs interfaces for managing and
> monitoring secure updates to FPGA and BMC images.
>
> 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@intel.com>
> ---
> 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 | 134 ++++++++++++++++++
> 5 files changed, 179 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..2992488b717a
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-driver-intel-m10-bmc-secure
> @@ -0,0 +1,29 @@
> +What: /sys/bus/platform/devices/n3000bmc-secure.*.auto/security/sr_root_entry_hash
> +Date: Oct 2020
> +KernelVersion: 5.11
> +Contact: Russ Weight <russell.h.weight@intel.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/devices/n3000bmc-secure.*.auto/security/pr_root_entry_hash
> +Date: Oct 2020
> +KernelVersion: 5.11
> +Contact: Russ Weight <russell.h.weight@intel.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/devices/n3000bmc-secure.*.auto/security/bmc_root_entry_hash
> +Date: Oct 2020
> +KernelVersion: 5.11
> +Contact: Russ Weight <russell.h.weight@intel.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 23c655fc0001..bbd2366280de 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -6941,8 +6941,10 @@ M: Russ Weight <russell.h.weight@intel.com>
> L: linux-fpga@vger.kernel.org
> S: Maintained
> F: Documentation/ABI/testing/sysfs-class-fpga-sec-mgr
> +F: Documentation/ABI/testing/sysfs-driver-intel-m10-bmc-secure
> F: Documentation/fpga/fpga-sec-mgr.rst
> F: drivers/fpga/fpga-sec-mgr.c
> +F: drivers/fpga/intel-m10-bmc-secure.c
> F: include/linux/fpga/fpga-sec-mgr.h
>
> FPU EMULATOR
> diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig
> index 03e9a3b16e3e..a102ab1df7ae 100644
> --- a/drivers/fpga/Kconfig
> +++ b/drivers/fpga/Kconfig
> @@ -235,4 +235,15 @@ config FPGA_SEC_MGR
> region and for the BMC. Select this option to enable
> updates for secure FPGA devices.
>
> +config IFPGA_M10_BMC_SECURE
> + tristate "Intel MAX10 BMC Secure Update driver"
> + depends on MFD_INTEL_M10_BMC && FPGA_SEC_MGR
> + 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 22576d1a3996..7259f1ab2531 100644
> --- a/drivers/fpga/Makefile
> +++ b/drivers/fpga/Makefile
> @@ -24,6 +24,9 @@ obj-$(CONFIG_ALTERA_PR_IP_CORE_PLAT) += altera-pr-ip-core-plat.o
> # FPGA Security Manager Framework
> obj-$(CONFIG_FPGA_SEC_MGR) += fpga-sec-mgr.o
>
> +# FPGA Secure Update Drivers
> +obj-$(CONFIG_IFPGA_M10_BMC_SECURE) += intel-m10-bmc-secure.o
> +
> # FPGA Bridge Drivers
> obj-$(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..198bc8273d6b
> --- /dev/null
> +++ b/drivers/fpga/intel-m10-bmc-secure.c
> @@ -0,0 +1,134 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Intel Max10 Board Management Controller Secure Update Driver
> + *
> + * Copyright (C) 2019-2020 Intel Corporation. All rights reserved.
> + *
> + */
> +#include <linux/bitfield.h>
> +#include <linux/device.h>
> +#include <linux/fpga/fpga-sec-mgr.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;
> +};
> +
> +/* 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;
> + }
> +
> + ret = regmap_bulk_read(sec->m10bmc->regmap, reh_addr,
> + hash, sha_num_bytes / stride);

Assumes !(sha_num_bytes % stride)

Maybe add an assert.

Tom

> + 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_sec_mgr_ops m10bmc_sops = { };
> +
> +static int m10bmc_secure_probe(struct platform_device *pdev)
> +{
> + struct fpga_sec_mgr *smgr;
> + 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);
> +
> + smgr = devm_fpga_sec_mgr_create(sec->dev, "Max10 BMC Secure Update",
> + &m10bmc_sops, sec);
> + if (!smgr) {
> + dev_err(sec->dev, "Security manager failed to start\n");
> + return -ENOMEM;
> + }
> +
> + return devm_fpga_sec_mgr_register(sec->dev, smgr);
> +}
> +
> +static struct platform_driver intel_m10bmc_secure_driver = {
> + .probe = m10bmc_secure_probe,
> + .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");

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