Re: [PATCH v14 1/4] fpga: m10bmc-sec: create max10 bmc secure update driver
From: Xu Yilun
Date: Fri Sep 10 2021 - 11:20:13 EST
On Thu, Sep 09, 2021 at 04:33:01PM -0700, Russ Weight wrote:
> 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@xxxxxxxxx>
> Reviewed-by: Tom Rix <trix@xxxxxxxxxx>
> ---
> 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@xxxxxxxxx>
> +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@xxxxxxxxx>
> +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@xxxxxxxxx>
> +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@xxxxxxxxx>
> L: linux-fpga@xxxxxxxxxxxxxxx
> S: Maintained
> F: Documentation/ABI/testing/sysfs-class-fpga-image-load
> +F: Documentation/ABI/testing/sysfs-driver-intel-m10-bmc-secure
Should we change the name of the driver? Some keywords like "image load"
or "firmware update" should be in the name.
Thanks,
Yilun
> 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