The Arm specification TPM Service CRB over FF-A specification defines the FF-A messages to interact with a CRB-based TPM implemented as an FF-A secure partition.
Spec URL: https://developer.arm.com/documentation/den0138/latest/ This driver is probed when a TPM Secure Partition is discovered by the FF-A subsystem. It exposes APIs used by the TPM CRB driver to send notifications to the TPM. Signed-off-by: Stuart Yoder <[email protected]> --- drivers/char/tpm/Kconfig | 9 + drivers/char/tpm/Makefile | 1 + drivers/char/tpm/tpm_ffa_crb.c | 310 +++++++++++++++++++++++++++++++++ drivers/char/tpm/tpm_ffa_crb.h | 30 ++++ 4 files changed, 350 insertions(+) create mode 100644 drivers/char/tpm/tpm_ffa_crb.c create mode 100644 drivers/char/tpm/tpm_ffa_crb.h diff --git a/drivers/char/tpm/Kconfig b/drivers/char/tpm/Kconfig index 0fc9a510e059..af5ba7c63927 100644 --- a/drivers/char/tpm/Kconfig +++ b/drivers/char/tpm/Kconfig @@ -210,6 +210,15 @@ config TCG_CRB from within Linux. To compile this driver as a module, choose M here; the module will be called tpm_crb. +config TCG_ARM_FFA_CRB + tristate "TPM CRB over Arm FF-A Transport" + depends on ARM_FFA_TRANSPORT + default y if (TCG_CRB && ARM_FFA_TRANSPORT) + help + If the Arm FF-A transport is used to access the TPM say Yes. + To compile this driver as a module, choose M here; the module + will be called tpm_ffa_crb. + config TCG_VTPM_PROXY tristate "VTPM Proxy Interface" depends on TCG_TPM diff --git a/drivers/char/tpm/Makefile b/drivers/char/tpm/Makefile index 9bb142c75243..21f2eb5a485e 100644 --- a/drivers/char/tpm/Makefile +++ b/drivers/char/tpm/Makefile @@ -42,5 +42,6 @@ obj-$(CONFIG_TCG_IBMVTPM) += tpm_ibmvtpm.o obj-$(CONFIG_TCG_TIS_ST33ZP24) += st33zp24/ obj-$(CONFIG_TCG_XEN) += xen-tpmfront.o obj-$(CONFIG_TCG_CRB) += tpm_crb.o +obj-$(CONFIG_TCG_ARM_FFA_CRB) += tpm_ffa_crb.o obj-$(CONFIG_TCG_VTPM_PROXY) += tpm_vtpm_proxy.o obj-$(CONFIG_TCG_FTPM_TEE) += tpm_ftpm_tee.o diff --git a/drivers/char/tpm/tpm_ffa_crb.c b/drivers/char/tpm/tpm_ffa_crb.c new file mode 100644 index 000000000000..56bd77864a47 --- /dev/null +++ b/drivers/char/tpm/tpm_ffa_crb.c @@ -0,0 +1,310 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2024 Arm Ltd. + * + * Maintained by: <[email protected]> + * + * This device driver implements the TPM CRB start method + * as defined in the TPM Service Command Response Buffer + * Interface Over FF-A (DEN0138). + */ + +#define pr_fmt(fmt) "FFA_CRB: " fmt + +#include <linux/arm_ffa.h> +#include "tpm_ffa_crb.h" + +/* TPM service function status codes */ +#define FFA_CRB_OK 0x05000001 +#define FFA_CRB_OK_RESULTS_RETURNED 0x05000002 +#define FFA_CRB_NOFUNC 0x8e000001 +#define FFA_CRB_NOTSUP 0x8e000002 +#define FFA_CRB_INVARG 0x8e000005 +#define FFA_CRB_INV_CRB_CTRL_DATA 0x8e000006 +#define FFA_CRB_ALREADY 0x8e000009 +#define FFA_CRB_DENIED 0x8e00000a +#define FFA_CRB_NOMEM 0x8e00000b + +#define FFA_CRB_VERSION_MAJOR 1 +#define FFA_CRB_VERSION_MINOR 0 + +/* version encoding */ +#define FFA_CRB_MAJOR_VERSION_MASK GENMASK(30, 16) +#define FFA_CRB_MINOR_VERSION_MASK GENMASK(15, 0) +#define FFA_CRB_MAJOR_VERSION(x) ((u16)(FIELD_GET(FFA_CRB_MAJOR_VERSION_MASK, (x)))) +#define FFA_CRB_MINOR_VERSION(x) ((u16)(FIELD_GET(FFA_CRB_MINOR_VERSION_MASK, (x)))) + +/* + * Normal world sends requests with FFA_MSG_SEND_DIRECT_REQ and + * responses are returned with FFA_MSG_SEND_DIRECT_RESP for normal + * messages. + * + * All requests with FFA_MSG_SEND_DIRECT_REQ and FFA_MSG_SEND_DIRECT_RESP + * are using the AArch32 SMC calling convention with register usage as + * defined in FF-A specification: + * w0: Function ID (0x8400006F or 0x84000070) + * w1: Source/Destination IDs + * w2: Reserved (MBZ) + * w3-w7: Implementation defined, free to be used below + */ + +/* + * Returns the version of the interface that is available + * Call register usage: + * w3: Not used (MBZ) + * w4: TPM service function ID, FFA_CRB_GET_INTERFACE_VERSION + * w5-w7: Reserved (MBZ) + * + * Return register usage: + * w3: Not used (MBZ) + * w4: TPM service function status + * w5: TPM service interface version + * Bits[31:16]: major version + * Bits[15:0]: minor version + * w6-w7: Reserved (MBZ) + * + * Possible function status codes in register w4: + * CRB_FFA_OK_RESULTS_RETURNED: The version of the interface has been + * returned. + */ +#define FFA_CRB_GET_INTERFACE_VERSION 0x0f000001 + +/* + * Return information on a given feature of the TPM service + * Call register usage: + * w3: Not used (MBZ) + * w4: TPM service function ID, FFA_CRB_START + * w5: Start function qualifier + * Bits[31:8] (MBZ) + * Bits[7:0] + * 0: Notifies TPM that a command is ready to be processed + * 1: Notifies TPM that a locality request is ready to be processed + * w6: TPM locality, one of 0..4 + * -If the start function qualifier is 0, identifies the locality + * from where the command originated. + * -If the start function qualifier is 1, identifies the locality + * of the locality request + * w6-w7: Reserved (MBZ) + * + * Return register usage: + * w3: Not used (MBZ) + * w4: TPM service function status + * w5-w7: Reserved (MBZ) + * + * Possible function status codes in register w4: + * FFA_CRB_OK: the TPM service has been notified successfully + * FFA_CRB_INVARG: one or more arguments are not valid + * FFA_CRB_INV_CRB_CTRL_DATA: CRB control data or locality control + * data at the given TPM locality is not valid + * FFA_CRB_DENIED: the TPM has previously disabled locality requests and + * command processing at the given locality + */ +#define FFA_CRB_START 0x0f000201 + +struct ffa_crb { + struct ffa_device *ffa_dev; + u16 major_version; + u16 minor_version; + struct mutex msg_data_lock; + struct ffa_send_direct_data direct_msg_data; +}; + +static struct ffa_crb *ffa_crb; + +static int ffa_crb_to_linux_errno(int errno) +{ + int rc; + + switch (errno) { + case FFA_CRB_OK: + rc = 0; + break; + case FFA_CRB_OK_RESULTS_RETURNED: + rc = 0; + break; + case FFA_CRB_NOFUNC: + rc = -ENOENT; + break; + case FFA_CRB_NOTSUP: + rc = -EPERM; + break; + case FFA_CRB_INVARG: + rc = -EINVAL; + break; + case FFA_CRB_INV_CRB_CTRL_DATA: + rc = -ENOEXEC; + break; + case FFA_CRB_ALREADY: + rc = -EEXIST; + break; + case FFA_CRB_DENIED: + rc = -EACCES; + break; + case FFA_CRB_NOMEM: + rc = -ENOMEM; + break; + default: + rc = -EINVAL; + } + + return rc; +} + +int ffa_crb_init(void) +{ + if (ffa_crb == NULL) + return -ENOENT; + + if (IS_ERR_VALUE(ffa_crb)) + return -ENODEV; + + return 0; +} +EXPORT_SYMBOL_GPL(ffa_crb_init); + +static int __ffa_crb_send_recieve(unsigned long func_id, + unsigned long a0, unsigned long a1, unsigned long a2) +{ + int ret; + const struct ffa_msg_ops *msg_ops; + + if (ffa_crb == NULL) + return -ENOENT; + + msg_ops = ffa_crb->ffa_dev->ops->msg_ops; + + memset(&ffa_crb->direct_msg_data, 0x00, + sizeof(struct ffa_send_direct_data)); + + ffa_crb->direct_msg_data.data1 = func_id; + ffa_crb->direct_msg_data.data2 = a0; + ffa_crb->direct_msg_data.data3 = a1; + ffa_crb->direct_msg_data.data4 = a2; + + ret = msg_ops->sync_send_receive(ffa_crb->ffa_dev, + &ffa_crb->direct_msg_data); + if (!ret) + ret = ffa_crb_to_linux_errno(ffa_crb->direct_msg_data.data1); + + return ret; +} + +int ffa_crb_get_interface_version(uint16_t *major, uint16_t *minor) +{ + int rc; + + if (ffa_crb == NULL) + return -ENOENT; + + if (IS_ERR_VALUE(ffa_crb)) + return -ENODEV; + + if (major == NULL || minor == NULL) + return -EINVAL; + + guard(mutex)(&ffa_crb->msg_data_lock); + + rc = __ffa_crb_send_recieve(FFA_CRB_GET_INTERFACE_VERSION, 0x00, 0x00, 0x00); + if (!rc) { + *major = FFA_CRB_MAJOR_VERSION(ffa_crb->direct_msg_data.data2); + *minor = FFA_CRB_MINOR_VERSION(ffa_crb->direct_msg_data.data2); + } + + return rc; +} +EXPORT_SYMBOL_GPL(ffa_crb_get_interface_version); + +int ffa_crb_start(int request_type, int locality) +{ + if (ffa_crb == NULL) + return -ENOENT; + + if (IS_ERR_VALUE(ffa_crb)) + return -ENODEV; + + guard(mutex)(&ffa_crb->msg_data_lock); + + return __ffa_crb_send_recieve(FFA_CRB_START, request_type, locality, 0x00); +} +EXPORT_SYMBOL_GPL(ffa_crb_start); + +static int ffa_crb_probe(struct ffa_device *ffa_dev) +{ + int rc; + struct ffa_crb *p; + + /* only one instance of a TPM partition is supported */ + if (ffa_crb && !IS_ERR_VALUE(ffa_crb)) + return -EEXIST; + + ffa_crb = ERR_PTR(-ENODEV); // set ffa_crb so we can detect probe failure + + if (!ffa_partition_supports_direct_recv(ffa_dev)) { + pr_err("TPM partition doesn't support direct message receive.\n"); + return -EINVAL; + } + + p = kzalloc(sizeof(*ffa_crb), GFP_KERNEL); + if (!p) + return -ENOMEM; + ffa_crb = p; + + mutex_init(&ffa_crb->msg_data_lock); + ffa_crb->ffa_dev = ffa_dev; + ffa_dev_set_drvdata(ffa_dev, ffa_crb); + + /* if TPM is aarch32 use 32-bit SMCs */ + if (!ffa_partition_check_property(ffa_dev, FFA_PARTITION_AARCH64_EXEC)) + ffa_dev->ops->msg_ops->mode_32bit_set(ffa_dev); + + /* verify compatibility of TPM service version number */ + rc = ffa_crb_get_interface_version(&ffa_crb->major_version, + &ffa_crb->minor_version); + if (rc) { + pr_err("failed to get crb interface version. rc:%d", rc); + goto out; + } + + pr_info("ABI version %u.%u", ffa_crb->major_version, + ffa_crb->minor_version); + + if ((ffa_crb->major_version != FFA_CRB_VERSION_MAJOR) || + (ffa_crb->minor_version < FFA_CRB_VERSION_MINOR)) { + pr_err("Incompatible ABI version"); + goto out; + } + + return 0; + +out: + kfree(ffa_crb); + ffa_crb = ERR_PTR(-ENODEV); + return -EINVAL; +} + +static void ffa_crb_remove(struct ffa_device *ffa_dev) +{ + kfree(ffa_crb); + ffa_crb = NULL; +} + +static const struct ffa_device_id ffa_crb_device_id[] = { + /* 17b862a4-1806-4faf-86b3-089a58353861 */ + { UUID_INIT(0x17b862a4, 0x1806, 0x4faf, + 0x86, 0xb3, 0x08, 0x9a, 0x58, 0x35, 0x38, 0x61) }, + {} +}; + +static struct ffa_driver ffa_crb_driver = { + .name = "ffa-crb", + .probe = ffa_crb_probe, + .remove = ffa_crb_remove, + .id_table = ffa_crb_device_id, +}; + +module_ffa_driver(ffa_crb_driver); + +MODULE_AUTHOR("Arm"); +MODULE_DESCRIPTION("FFA CRB driver"); +MODULE_VERSION("1.0"); +MODULE_LICENSE("GPL"); diff --git a/drivers/char/tpm/tpm_ffa_crb.h b/drivers/char/tpm/tpm_ffa_crb.h new file mode 100644 index 000000000000..42327d285165 --- /dev/null +++ b/drivers/char/tpm/tpm_ffa_crb.h @@ -0,0 +1,30 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) 2024 Arm Ltd. + * + * Authors: + * Stuart Yoder <[email protected]> + * + * Maintained by: <[email protected]> + * + * This device driver implements the TPM CRB start method + * as defined in the TPM Service Command Response Buffer + * Interface Over FF-A (DEN0138). + */ +#ifndef _FFA_CRB_H +#define _FFA_CRB_H + +#if IS_ENABLED(CONFIG_TCG_ARM_FFA_CRB) +int ffa_crb_init(void); +int ffa_crb_get_interface_version(uint16_t *major, uint16_t *minor); +int ffa_crb_start(int request_type, int locality); +#else +static inline int ffa_crb_init(void) { return 0; } +static inline int ffa_crb_get_interface_version(uint16_t *major, uint16_t *minor) { return 0; } +static inline int ffa_crb_start(int request_type, int locality) { return 0; } +#endif + +#define FFA_CRB_START_TYPE_COMMAND 0 +#define FFA_CRB_START_TYPE_LOCALITY_REQUEST 1 + +#endif -- 2.34.1
