Re: [PATCH v1 02/12] fpga: create intel max10 bmc security engine

Tom Rix
2020-09-05T20:22:14Z

On 9/4/20 4:52 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 Intel 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 Security Engine driver and
> provides support 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>
> Reviewed-by: Wu Hao <hao.wu@intel.com>
> ---
> drivers/fpga/Kconfig | 11 ++
> drivers/fpga/Makefile | 3 +
> drivers/fpga/intel-m10-bmc-secure.c | 170 ++++++++++++++++++++++++++++
> include/linux/mfd/intel-m10-bmc.h | 15 +++
> 4 files changed, 199 insertions(+)
> create mode 100644 drivers/fpga/intel-m10-bmc-secure.c
>
> diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig
> index 97c0a6cc2ba7..0f0bed68e618 100644
> --- a/drivers/fpga/Kconfig
> +++ b/drivers/fpga/Kconfig
> @@ -244,4 +244,15 @@ config IFPGA_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 security engine"
> + depends on MFD_INTEL_M10_BMC && IFPGA_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 ec9fbacdedd8..451a23ec3168 100644
> --- a/drivers/fpga/Makefile
> +++ b/drivers/fpga/Makefile
> @@ -24,6 +24,9 @@ obj-$(CONFIG_ALTERA_PR_IP_CORE_PLAT) += altera-pr-ip-core-plat.o
> # Intel FPGA Security Manager Framework
> obj-$(CONFIG_IFPGA_SEC_MGR) += ifpga-sec-mgr.o
>
> +# Intel Security Manager 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..1f86bfb694b4
> --- /dev/null
> +++ b/drivers/fpga/intel-m10-bmc-secure.c
> @@ -0,0 +1,170 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Intel Max10 Board Management Controller Security Engine Driver
> + *
> + * Copyright (C) 2019-2020 Intel Corporation. All rights reserved.
> + *
> + */
> +#include <linux/device.h>
> +#include <linux/fpga/ifpga-sec-mgr.h>
> +#include <linux/mfd/intel-m10-bmc.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/vmalloc.h>
> +
> +struct m10bmc_sec {
> + struct device *dev;
> + struct intel_m10bmc *m10bmc;
> + struct ifpga_sec_mgr *imgr;
> +};
> +
> +#define SHA256_REH_SIZE 32
> +#define SHA384_REH_SIZE 48
> +
> +static int get_reh_size(struct ifpga_sec_mgr *imgr,
> + u32 exp_magic, u32 prog_addr)
> +{
> + struct m10bmc_sec *sec = imgr->priv;
> + int sha_num_bytes, ret;
> + u32 magic;
> +
> + ret = m10bmc_raw_read(sec->m10bmc, prog_addr, &magic);
> + if (ret)
> + return ret;
> +
> + dev_dbg(sec->dev, "%s magic 0x%08x\n", __func__, magic);
> +
> + if ((magic & 0xffff) != exp_magic)
return -EINVAL ?
> + return 0;
> +
> + sha_num_bytes = ((magic >> 16) & 0xffff) / 8;
> +
> + if (sha_num_bytes != SHA256_REH_SIZE &&
> + sha_num_bytes != SHA384_REH_SIZE) {
> + dev_err(sec->dev, "%s bad sha num bytes %d\n", __func__,
> + sha_num_bytes);
> + return -EINVAL;
> + }
> +
> + return sha_num_bytes;
> +}
> +
> +#define BMC_REH_ADDR 0x17ffc004
> +#define BMC_PROG_ADDR 0x17ffc000
> +#define BMC_PROG_MAGIC 0x5746
> +
> +#define SR_REH_ADDR 0x17ffd004
> +#define SR_PROG_ADDR 0x17ffd000
> +#define SR_PROG_MAGIC 0x5253
> +
> +#define PR_REH_ADDR 0x17ffe004
> +#define PR_PROG_ADDR 0x17ffe000
> +#define PR_PROG_MAGIC 0x5250
Why shouldn't these #defines be collected in the intel-m10-bmc.h ?
> +
> +#define SYSFS_GET_REH_SIZE(_name, _exp_magic, _prog_addr) \
> +static int get_##_name##_reh_size(struct ifpga_sec_mgr *imgr) \
> +{ \
> + return get_reh_size(imgr, _exp_magic, _prog_addr); \
> +}
Is this macro overkill for a 1 liner ?
> +
> +SYSFS_GET_REH_SIZE(bmc, BMC_PROG_MAGIC, BMC_PROG_ADDR)
> +SYSFS_GET_REH_SIZE(sr, SR_PROG_MAGIC, SR_PROG_ADDR)
> +SYSFS_GET_REH_SIZE(pr, PR_PROG_MAGIC, PR_PROG_ADDR)

These and similar below do not directly interact

with the sysfs so the sysfs_ prefix should not be needed.

> +
> +static int get_root_entry_hash(struct ifpga_sec_mgr *imgr,
> + u32 hash_addr, u8 *hash,
> + unsigned int size)
> +{
> + struct m10bmc_sec *sec = imgr->priv;
> + unsigned int stride = regmap_get_reg_stride(sec->m10bmc->regmap);
> + int ret;
> +
> + ret = m10bmc_raw_bulk_read(sec->m10bmc, hash_addr,
> + hash, size / stride);
> + if (ret)
> + dev_err(sec->dev, "bulk_read of 0x%x failed %d",
> + hash_addr, ret);
> +
> + return ret;
> +}
> +
> +#define SYSFS_GET_REH(_name, _hash_addr) \
> +static int get_##_name##_root_entry_hash(struct ifpga_sec_mgr *imgr, \
> + u8 *hash, unsigned int size) \
> +{ \
> + return get_root_entry_hash(imgr, _hash_addr, hash, size); \
> +}
> +
> +SYSFS_GET_REH(bmc, BMC_REH_ADDR)
> +SYSFS_GET_REH(sr, SR_REH_ADDR)
> +SYSFS_GET_REH(pr, PR_REH_ADDR)
> +
> +static const struct ifpga_sec_mgr_ops m10bmc_iops = {
> + .bmc_root_entry_hash = get_bmc_root_entry_hash,
> + .sr_root_entry_hash = get_sr_root_entry_hash,
> + .pr_root_entry_hash = get_pr_root_entry_hash,
> + .bmc_reh_size = get_bmc_reh_size,
> + .sr_reh_size = get_sr_reh_size,
> + .pr_reh_size = get_pr_reh_size,

The prefix of the ops should be similar to the file name.

so consider changing get_pr_reh_size to max10_pr_reh_size

> +};
> +
> +static void ifpga_sec_mgr_uinit(struct m10bmc_sec *sec)
> +{
> + ifpga_sec_mgr_unregister(sec->imgr);
> +}
> +
> +static int ifpga_sec_mgr_init(struct m10bmc_sec *sec)
> +{
> + struct ifpga_sec_mgr *imgr;
> +
> + imgr = ifpga_sec_mgr_register(sec->dev, "Max10 BMC Security Manager",
> + &m10bmc_iops, sec);
> + if (IS_ERR(imgr))
> + return PTR_ERR(imgr);
> +
> + sec->imgr = imgr;
> + return 0;
> +}
> +
> +static int m10bmc_secure_probe(struct platform_device *pdev)
> +{
> + struct m10bmc_sec *sec;
> + int ret;
> +
> + 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);
> +
> + ret = ifpga_sec_mgr_init(sec);
> + if (ret)
> + dev_err(&pdev->dev,
> + "Security manager failed to start: %d\n", ret);
> +
> + return ret;
> +}
> +
> +static int m10bmc_secure_remove(struct platform_device *pdev)
> +{
> + struct m10bmc_sec *sec = dev_get_drvdata(&pdev->dev);
> +
> + ifpga_sec_mgr_uinit(sec);
> + return 0;
> +}
> +
> +static struct platform_driver intel_m10bmc_secure_driver = {
> + .probe = m10bmc_secure_probe,
> + .remove = m10bmc_secure_remove,
> + .driver = {
> + .name = "n3000bmc-secure",

From the filename, should this be "max10bmc-secure" ?

> + },
> +};
> +module_platform_driver(intel_m10bmc_secure_driver);
> +
> +MODULE_ALIAS("platform:n3000bmc-secure");
> +MODULE_AUTHOR("Intel Corporation");
> +MODULE_DESCRIPTION("Intel MAX10 BMC secure engine");
> +MODULE_LICENSE("GPL v2");
> diff --git a/include/linux/mfd/intel-m10-bmc.h b/include/linux/mfd/intel-m10-bmc.h
> index d4cb01b73357..7fe465c320c2 100644
> --- a/include/linux/mfd/intel-m10-bmc.h
> +++ b/include/linux/mfd/intel-m10-bmc.h
> @@ -63,6 +63,7 @@ struct intel_m10bmc {
> * register access helper functions.
> *
> * m10bmc_raw_read - read m10bmc register per addr
> + * m10bmc_raw_bulk_read - bulk_read max10 registers per addr

second '_' should be removed so it reads like

bulk read max10 registers..

Tom

> * m10bmc_sys_read - read m10bmc system register per offset
> */
> static inline int
> @@ -79,6 +80,20 @@ m10bmc_raw_read(struct intel_m10bmc *m10bmc, unsigned int addr,
> return ret;
> }
>
> +static inline int
> +m10bmc_raw_bulk_read(struct intel_m10bmc *m10bmc, unsigned int addr,
> + void *val, size_t cnt)
> +{
> + int ret;
> +
> + ret = regmap_bulk_read(m10bmc->regmap, addr, val, cnt);
> + if (ret)
> + dev_err(m10bmc->dev, "fail to read raw reg %x cnt %zx: %d\n",
> + addr, cnt, ret);
> +
> + return ret;
> +}
> +
> #define m10bmc_sys_read(m10bmc, offset, val) \
> m10bmc_raw_read(m10bmc, M10BMC_SYS_BASE + (offset), val)
>