| Message ID | 20250217224946.113951-2-stuart.yoder@arm.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Add support for the TPM FF-A start method | expand |
On Mon, 2025-02-17 at 16:49 -0600, Stuart Yoder wrote: > 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 <stuart.yoder@arm.com> > --- > drivers/char/tpm/Kconfig | 9 + > drivers/char/tpm/Makefile | 1 + > drivers/char/tpm/tpm_crb_ffa.c | 348 > +++++++++++++++++++++++++++++++++ > drivers/char/tpm/tpm_crb_ffa.h | 25 +++ > 4 files changed, 383 insertions(+) > create mode 100644 drivers/char/tpm/tpm_crb_ffa.c > create mode 100644 drivers/char/tpm/tpm_crb_ffa.h > > diff --git a/drivers/char/tpm/Kconfig b/drivers/char/tpm/Kconfig > index 0fc9a510e059..4c85b8c00b12 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_CRB_FFA > + 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_crb_ffa. > + > 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..2b004df8c04b 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-$(CONFIG_TCG_ARM_CRB_FFA) += tpm_crb_ffa.o > obj-$(CONFIG_TCG_VTPM_PROXY) += tpm_vtpm_proxy.o > obj-$(CONFIG_TCG_FTPM_TEE) += tpm_ftpm_tee.o > diff --git a/drivers/char/tpm/tpm_crb_ffa.c > b/drivers/char/tpm/tpm_crb_ffa.c > new file mode 100644 > index 000000000000..bd3c6c41264b > --- /dev/null > +++ b/drivers/char/tpm/tpm_crb_ffa.c > @@ -0,0 +1,348 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * Copyright (C) 2024 Arm Ltd. Agreed that, this type of copyright makes sense. It would be harder to decipher the data from the commit log. Also one corner case where I plan to use copyrighta in-file personally: I'm mainlining an OOT driver with a bunch of contributors over time, and in that I'll list all the historical contributors with appropriate copyright platters :-) Generally speaking, I think can be added as long as it has an actual function that brings measurable value. > + * > + * 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) "CRB_FFA: " fmt > + > +#include <linux/arm_ffa.h> > +#include "tpm_crb_ffa.h" > + > +/* TPM service function status codes */ > +#define CRB_FFA_OK 0x05000001 > +#define CRB_FFA_OK_RESULTS_RETURNED 0x05000002 > +#define CRB_FFA_NOFUNC 0x8e000001 > +#define CRB_FFA_NOTSUP 0x8e000002 > +#define CRB_FFA_INVARG 0x8e000005 > +#define CRB_FFA_INV_CRB_CTRL_DATA 0x8e000006 > +#define CRB_FFA_ALREADY 0x8e000009 > +#define CRB_FFA_DENIED 0x8e00000a > +#define CRB_FFA_NOMEM 0x8e00000b > + > +#define CRB_FFA_VERSION_MAJOR 1 > +#define CRB_FFA_VERSION_MINOR 0 > + > +/* version encoding */ > +#define CRB_FFA_MAJOR_VERSION_MASK GENMASK(30, 16) > +#define CRB_FFA_MINOR_VERSION_MASK GENMASK(15, 0) > +#define CRB_FFA_MAJOR_VERSION(x) > ((u16)(FIELD_GET(CRB_FFA_MAJOR_VERSION_MASK, (x)))) > +#define CRB_FFA_MINOR_VERSION(x) > ((u16)(FIELD_GET(CRB_FFA_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, CRB_FFA_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 CRB_FFA_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, CRB_FFA_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: > + * CRB_FFA_OK: the TPM service has been notified successfully > + * CRB_FFA_INVARG: one or more arguments are not valid > + * CRB_FFA_INV_CRB_CTRL_DATA: CRB control data or locality > control > + * data at the given TPM locality is not valid > + * CRB_FFA_DENIED: the TPM has previously disabled locality > requests and > + * command processing at the given locality > + */ > +#define CRB_FFA_START 0x0f000201 > + > +struct tpm_crb_ffa { > + struct ffa_device *ffa_dev; > + u16 major_version; > + u16 minor_version; > + struct mutex msg_data_lock; /* lock to protect sending of > FF-A messages */ Nit: /* Lock to protect sending of FFA-messages: */ struct mutex msg_data_lock; It is a bit more readable and double comma makes pretty obvious which field it is pointing at. > + struct ffa_send_direct_data direct_msg_data; > +}; > + > +static struct tpm_crb_ffa *tpm_crb_ffa; > + > +static int tpm_crb_ffa_to_linux_errno(int errno) > +{ > + int rc; > + > + switch (errno) { > + case CRB_FFA_OK: > + rc = 0; > + break; > + case CRB_FFA_OK_RESULTS_RETURNED: > + rc = 0; > + break; > + case CRB_FFA_NOFUNC: > + rc = -ENOENT; > + break; > + case CRB_FFA_NOTSUP: > + rc = -EPERM; > + break; > + case CRB_FFA_INVARG: > + rc = -EINVAL; > + break; > + case CRB_FFA_INV_CRB_CTRL_DATA: > + rc = -ENOEXEC; > + break; > + case CRB_FFA_ALREADY: > + rc = -EEXIST; > + break; > + case CRB_FFA_DENIED: > + rc = -EACCES; > + break; > + case CRB_FFA_NOMEM: > + rc = -ENOMEM; > + break; > + default: > + rc = -EINVAL; > + } > + > + return rc; > +} > + > +/** > + * tpm_crb_ffa_init - called by the CRB driver to do any needed > initialization > + * > + * This function is called by the tpm_crb driver during the tpm_crb > + * driver's initialization. If the tpm_crb_ffa has not been probed > + * yet, returns -ENOENT in order to force a retry. If th ffa_crb > + * driver had been probed but failed with an error, returns -ENODEV > + * in order to prevent further retries. > + * > + * Return: 0 on success, negative error code on failure. > + */ > +int tpm_crb_ffa_init(void) > +{ > + if (!tpm_crb_ffa) > + return -ENOENT; > + > + if (IS_ERR_VALUE(tpm_crb_ffa)) > + return -ENODEV; > + > + return 0; > +} > +EXPORT_SYMBOL_GPL(tpm_crb_ffa_init); > + > +static int __tpm_crb_ffa_send_recieve(unsigned long func_id, > + unsigned long a0, > + unsigned long a1, > + unsigned long a2) > +{ > + const struct ffa_msg_ops *msg_ops; > + int ret; > + > + if (!tpm_crb_ffa) > + return -ENOENT; > + > + msg_ops = tpm_crb_ffa->ffa_dev->ops->msg_ops; > + > + memset(&tpm_crb_ffa->direct_msg_data, 0x00, > + sizeof(struct ffa_send_direct_data)); > + > + tpm_crb_ffa->direct_msg_data.data1 = func_id; > + tpm_crb_ffa->direct_msg_data.data2 = a0; > + tpm_crb_ffa->direct_msg_data.data3 = a1; > + tpm_crb_ffa->direct_msg_data.data4 = a2; > + > + ret = msg_ops->sync_send_receive(tpm_crb_ffa->ffa_dev, > + &tpm_crb_ffa->direct_msg_data); > + if (!ret) > + ret = tpm_crb_ffa_to_linux_errno(tpm_crb_ffa- > >direct_msg_data.data1); > + > + return ret; > +} > + > +/** > + * tpm_crb_ffa_get_interface_version() - gets the ABI version of the > TPM service > + * @major: Pointer to caller-allocated buffer to hold the major > version > + * number the ABI > + * @minor: Pointer to caller-allocated buffer to hold the minor > version > + * number the ABI > + * > + * Returns the major and minor version of the ABI of the FF-A based > TPM. > + * Allows the caller to evaluate its compatibility with the version > of > + * the ABI. > + * > + * Return: 0 on success, negative error code on failure. > + */ > +int tpm_crb_ffa_get_interface_version(u16 *major, u16 *minor) > +{ > + int rc; > + > + if (!tpm_crb_ffa) > + return -ENOENT; > + > + if (IS_ERR_VALUE(tpm_crb_ffa)) > + return -ENODEV; > + > + if (!major || !minor) > + return -EINVAL; > + > + guard(mutex)(&tpm_crb_ffa->msg_data_lock); > + > + rc = > __tpm_crb_ffa_send_recieve(CRB_FFA_GET_INTERFACE_VERSION, 0x00, 0x00, > 0x00); > + if (!rc) { > + *major = CRB_FFA_MAJOR_VERSION(tpm_crb_ffa- > >direct_msg_data.data2); > + *minor = CRB_FFA_MINOR_VERSION(tpm_crb_ffa- > >direct_msg_data.data2); > + } > + > + return rc; > +} > +EXPORT_SYMBOL_GPL(tpm_crb_ffa_get_interface_version); > + > +/** > + * tpm_crb_ffa_start() - signals the TPM that a field has changed in > the CRB > + * @request_type: Identifies whether the change to the CRB is in the > command > + * fields or locality fields. > + * @locality: Specifies the locality number. > + * > + * Used by the CRB driver > + * that might be useful to those using or modifying it. Begins with > + * empty comment line, and may include additional embedded empty > + * comment lines. > + * > + * Return: 0 on success, negative error code on failure. > + */ > +int tpm_crb_ffa_start(int request_type, int locality) > +{ > + if (!tpm_crb_ffa) > + return -ENOENT; > + > + if (IS_ERR_VALUE(tpm_crb_ffa)) > + return -ENODEV; > + > + guard(mutex)(&tpm_crb_ffa->msg_data_lock); > + > + return __tpm_crb_ffa_send_recieve(CRB_FFA_START, > request_type, locality, 0x00); > +} > +EXPORT_SYMBOL_GPL(tpm_crb_ffa_start); > + > +static int tpm_crb_ffa_probe(struct ffa_device *ffa_dev) > +{ > + struct tpm_crb_ffa *p; > + int rc; > + > + /* only one instance of a TPM partition is supported */ > + if (tpm_crb_ffa && !IS_ERR_VALUE(tpm_crb_ffa)) > + return -EEXIST; > + > + tpm_crb_ffa = ERR_PTR(-ENODEV); // set tpm_crb_ffa 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(*tpm_crb_ffa), GFP_KERNEL); > + if (!p) > + return -ENOMEM; > + tpm_crb_ffa = p; > + > + mutex_init(&tpm_crb_ffa->msg_data_lock); > + tpm_crb_ffa->ffa_dev = ffa_dev; > + ffa_dev_set_drvdata(ffa_dev, tpm_crb_ffa); > + > + /* 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 = tpm_crb_ffa_get_interface_version(&tpm_crb_ffa- > >major_version, > + &tpm_crb_ffa- > >minor_version); > + if (rc) { > + pr_err("failed to get crb interface version. rc:%d", > rc); > + goto out; > + } > + > + pr_info("ABI version %u.%u", tpm_crb_ffa->major_version, > + tpm_crb_ffa->minor_version); > + > + if (tpm_crb_ffa->major_version != CRB_FFA_VERSION_MAJOR || > + (tpm_crb_ffa->minor_version > 0 && > + tpm_crb_ffa->minor_version < CRB_FFA_VERSION_MINOR)) { > + pr_err("Incompatible ABI version"); > + goto out; > + } > + > + return 0; > + > +out: > + kfree(tpm_crb_ffa); > + tpm_crb_ffa = ERR_PTR(-ENODEV); > + return -EINVAL; > +} > + > +static void tpm_crb_ffa_remove(struct ffa_device *ffa_dev) > +{ > + kfree(tpm_crb_ffa); > + tpm_crb_ffa = NULL; > +} > + > +static const struct ffa_device_id tpm_crb_ffa_device_id[] = { > + /* 17b862a4-1806-4faf-86b3-089a58353861 */ > + { UUID_INIT(0x17b862a4, 0x1806, 0x4faf, > + 0x86, 0xb3, 0x08, 0x9a, 0x58, 0x35, 0x38, 0x61) > }, > + {} > +}; > + > +static struct ffa_driver tpm_crb_ffa_driver = { > + .name = "ffa-crb", > + .probe = tpm_crb_ffa_probe, > + .remove = tpm_crb_ffa_remove, > + .id_table = tpm_crb_ffa_device_id, > +}; > + > +module_ffa_driver(tpm_crb_ffa_driver); > + > +MODULE_AUTHOR("Arm"); > +MODULE_DESCRIPTION("FFA CRB driver"); > +MODULE_VERSION("1.0"); Take this with a grain of salt, i.e. I'm not going to NAK for this but I would not personally add MODULE_VERSION() for new drivers as it does not have any function. > +MODULE_LICENSE("GPL"); > diff --git a/drivers/char/tpm/tpm_crb_ffa.h > b/drivers/char/tpm/tpm_crb_ffa.h > new file mode 100644 > index 000000000000..23a9b93287a1 > --- /dev/null > +++ b/drivers/char/tpm/tpm_crb_ffa.h > @@ -0,0 +1,25 @@ > +/* SPDX-License-Identifier: GPL-2.0-only */ > +/* > + * Copyright (C) 2024 Arm Ltd. > + * > + * This device driver implements the TPM CRB start method > + * as defined in the TPM Service Command Response Buffer > + * Interface Over FF-A (DEN0138). > + */ > +#ifndef _TPM_CRB_FFA_H > +#define _TPM_CRB_FFA_H > + > +#if IS_ENABLED(CONFIG_TCG_ARM_CRB_FFA) > +int tpm_crb_ffa_init(void); > +int tpm_crb_ffa_get_interface_version(u16 *major, u16 *minor); > +int tpm_crb_ffa_start(int request_type, int locality); > +#else > +static inline int tpm_crb_ffa_init(void) { return 0; } > +static inline int tpm_crb_ffa_get_interface_version(u16 *major, u16 > *minor) { return 0; } > +static inline int tpm_crb_ffa_start(int request_type, int locality) > { return 0; } > +#endif > + > +#define CRB_FFA_START_TYPE_COMMAND 0 > +#define CRB_FFA_START_TYPE_LOCALITY_REQUEST 1 > + > +#endif BR, Jarkko
diff --git a/drivers/char/tpm/Kconfig b/drivers/char/tpm/Kconfig index 0fc9a510e059..4c85b8c00b12 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_CRB_FFA + 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_crb_ffa. + 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..2b004df8c04b 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_CRB_FFA) += tpm_crb_ffa.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_crb_ffa.c b/drivers/char/tpm/tpm_crb_ffa.c new file mode 100644 index 000000000000..bd3c6c41264b --- /dev/null +++ b/drivers/char/tpm/tpm_crb_ffa.c @@ -0,0 +1,348 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2024 Arm Ltd. + * + * 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) "CRB_FFA: " fmt + +#include <linux/arm_ffa.h> +#include "tpm_crb_ffa.h" + +/* TPM service function status codes */ +#define CRB_FFA_OK 0x05000001 +#define CRB_FFA_OK_RESULTS_RETURNED 0x05000002 +#define CRB_FFA_NOFUNC 0x8e000001 +#define CRB_FFA_NOTSUP 0x8e000002 +#define CRB_FFA_INVARG 0x8e000005 +#define CRB_FFA_INV_CRB_CTRL_DATA 0x8e000006 +#define CRB_FFA_ALREADY 0x8e000009 +#define CRB_FFA_DENIED 0x8e00000a +#define CRB_FFA_NOMEM 0x8e00000b + +#define CRB_FFA_VERSION_MAJOR 1 +#define CRB_FFA_VERSION_MINOR 0 + +/* version encoding */ +#define CRB_FFA_MAJOR_VERSION_MASK GENMASK(30, 16) +#define CRB_FFA_MINOR_VERSION_MASK GENMASK(15, 0) +#define CRB_FFA_MAJOR_VERSION(x) ((u16)(FIELD_GET(CRB_FFA_MAJOR_VERSION_MASK, (x)))) +#define CRB_FFA_MINOR_VERSION(x) ((u16)(FIELD_GET(CRB_FFA_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, CRB_FFA_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 CRB_FFA_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, CRB_FFA_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: + * CRB_FFA_OK: the TPM service has been notified successfully + * CRB_FFA_INVARG: one or more arguments are not valid + * CRB_FFA_INV_CRB_CTRL_DATA: CRB control data or locality control + * data at the given TPM locality is not valid + * CRB_FFA_DENIED: the TPM has previously disabled locality requests and + * command processing at the given locality + */ +#define CRB_FFA_START 0x0f000201 + +struct tpm_crb_ffa { + struct ffa_device *ffa_dev; + u16 major_version; + u16 minor_version; + struct mutex msg_data_lock; /* lock to protect sending of FF-A messages */ + struct ffa_send_direct_data direct_msg_data; +}; + +static struct tpm_crb_ffa *tpm_crb_ffa; + +static int tpm_crb_ffa_to_linux_errno(int errno) +{ + int rc; + + switch (errno) { + case CRB_FFA_OK: + rc = 0; + break; + case CRB_FFA_OK_RESULTS_RETURNED: + rc = 0; + break; + case CRB_FFA_NOFUNC: + rc = -ENOENT; + break; + case CRB_FFA_NOTSUP: + rc = -EPERM; + break; + case CRB_FFA_INVARG: + rc = -EINVAL; + break; + case CRB_FFA_INV_CRB_CTRL_DATA: + rc = -ENOEXEC; + break; + case CRB_FFA_ALREADY: + rc = -EEXIST; + break; + case CRB_FFA_DENIED: + rc = -EACCES; + break; + case CRB_FFA_NOMEM: + rc = -ENOMEM; + break; + default: + rc = -EINVAL; + } + + return rc; +} + +/** + * tpm_crb_ffa_init - called by the CRB driver to do any needed initialization + * + * This function is called by the tpm_crb driver during the tpm_crb + * driver's initialization. If the tpm_crb_ffa has not been probed + * yet, returns -ENOENT in order to force a retry. If th ffa_crb + * driver had been probed but failed with an error, returns -ENODEV + * in order to prevent further retries. + * + * Return: 0 on success, negative error code on failure. + */ +int tpm_crb_ffa_init(void) +{ + if (!tpm_crb_ffa) + return -ENOENT; + + if (IS_ERR_VALUE(tpm_crb_ffa)) + return -ENODEV; + + return 0; +} +EXPORT_SYMBOL_GPL(tpm_crb_ffa_init); + +static int __tpm_crb_ffa_send_recieve(unsigned long func_id, + unsigned long a0, + unsigned long a1, + unsigned long a2) +{ + const struct ffa_msg_ops *msg_ops; + int ret; + + if (!tpm_crb_ffa) + return -ENOENT; + + msg_ops = tpm_crb_ffa->ffa_dev->ops->msg_ops; + + memset(&tpm_crb_ffa->direct_msg_data, 0x00, + sizeof(struct ffa_send_direct_data)); + + tpm_crb_ffa->direct_msg_data.data1 = func_id; + tpm_crb_ffa->direct_msg_data.data2 = a0; + tpm_crb_ffa->direct_msg_data.data3 = a1; + tpm_crb_ffa->direct_msg_data.data4 = a2; + + ret = msg_ops->sync_send_receive(tpm_crb_ffa->ffa_dev, + &tpm_crb_ffa->direct_msg_data); + if (!ret) + ret = tpm_crb_ffa_to_linux_errno(tpm_crb_ffa->direct_msg_data.data1); + + return ret; +} + +/** + * tpm_crb_ffa_get_interface_version() - gets the ABI version of the TPM service + * @major: Pointer to caller-allocated buffer to hold the major version + * number the ABI + * @minor: Pointer to caller-allocated buffer to hold the minor version + * number the ABI + * + * Returns the major and minor version of the ABI of the FF-A based TPM. + * Allows the caller to evaluate its compatibility with the version of + * the ABI. + * + * Return: 0 on success, negative error code on failure. + */ +int tpm_crb_ffa_get_interface_version(u16 *major, u16 *minor) +{ + int rc; + + if (!tpm_crb_ffa) + return -ENOENT; + + if (IS_ERR_VALUE(tpm_crb_ffa)) + return -ENODEV; + + if (!major || !minor) + return -EINVAL; + + guard(mutex)(&tpm_crb_ffa->msg_data_lock); + + rc = __tpm_crb_ffa_send_recieve(CRB_FFA_GET_INTERFACE_VERSION, 0x00, 0x00, 0x00); + if (!rc) { + *major = CRB_FFA_MAJOR_VERSION(tpm_crb_ffa->direct_msg_data.data2); + *minor = CRB_FFA_MINOR_VERSION(tpm_crb_ffa->direct_msg_data.data2); + } + + return rc; +} +EXPORT_SYMBOL_GPL(tpm_crb_ffa_get_interface_version); + +/** + * tpm_crb_ffa_start() - signals the TPM that a field has changed in the CRB + * @request_type: Identifies whether the change to the CRB is in the command + * fields or locality fields. + * @locality: Specifies the locality number. + * + * Used by the CRB driver + * that might be useful to those using or modifying it. Begins with + * empty comment line, and may include additional embedded empty + * comment lines. + * + * Return: 0 on success, negative error code on failure. + */ +int tpm_crb_ffa_start(int request_type, int locality) +{ + if (!tpm_crb_ffa) + return -ENOENT; + + if (IS_ERR_VALUE(tpm_crb_ffa)) + return -ENODEV; + + guard(mutex)(&tpm_crb_ffa->msg_data_lock); + + return __tpm_crb_ffa_send_recieve(CRB_FFA_START, request_type, locality, 0x00); +} +EXPORT_SYMBOL_GPL(tpm_crb_ffa_start); + +static int tpm_crb_ffa_probe(struct ffa_device *ffa_dev) +{ + struct tpm_crb_ffa *p; + int rc; + + /* only one instance of a TPM partition is supported */ + if (tpm_crb_ffa && !IS_ERR_VALUE(tpm_crb_ffa)) + return -EEXIST; + + tpm_crb_ffa = ERR_PTR(-ENODEV); // set tpm_crb_ffa 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(*tpm_crb_ffa), GFP_KERNEL); + if (!p) + return -ENOMEM; + tpm_crb_ffa = p; + + mutex_init(&tpm_crb_ffa->msg_data_lock); + tpm_crb_ffa->ffa_dev = ffa_dev; + ffa_dev_set_drvdata(ffa_dev, tpm_crb_ffa); + + /* 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 = tpm_crb_ffa_get_interface_version(&tpm_crb_ffa->major_version, + &tpm_crb_ffa->minor_version); + if (rc) { + pr_err("failed to get crb interface version. rc:%d", rc); + goto out; + } + + pr_info("ABI version %u.%u", tpm_crb_ffa->major_version, + tpm_crb_ffa->minor_version); + + if (tpm_crb_ffa->major_version != CRB_FFA_VERSION_MAJOR || + (tpm_crb_ffa->minor_version > 0 && + tpm_crb_ffa->minor_version < CRB_FFA_VERSION_MINOR)) { + pr_err("Incompatible ABI version"); + goto out; + } + + return 0; + +out: + kfree(tpm_crb_ffa); + tpm_crb_ffa = ERR_PTR(-ENODEV); + return -EINVAL; +} + +static void tpm_crb_ffa_remove(struct ffa_device *ffa_dev) +{ + kfree(tpm_crb_ffa); + tpm_crb_ffa = NULL; +} + +static const struct ffa_device_id tpm_crb_ffa_device_id[] = { + /* 17b862a4-1806-4faf-86b3-089a58353861 */ + { UUID_INIT(0x17b862a4, 0x1806, 0x4faf, + 0x86, 0xb3, 0x08, 0x9a, 0x58, 0x35, 0x38, 0x61) }, + {} +}; + +static struct ffa_driver tpm_crb_ffa_driver = { + .name = "ffa-crb", + .probe = tpm_crb_ffa_probe, + .remove = tpm_crb_ffa_remove, + .id_table = tpm_crb_ffa_device_id, +}; + +module_ffa_driver(tpm_crb_ffa_driver); + +MODULE_AUTHOR("Arm"); +MODULE_DESCRIPTION("FFA CRB driver"); +MODULE_VERSION("1.0"); +MODULE_LICENSE("GPL"); diff --git a/drivers/char/tpm/tpm_crb_ffa.h b/drivers/char/tpm/tpm_crb_ffa.h new file mode 100644 index 000000000000..23a9b93287a1 --- /dev/null +++ b/drivers/char/tpm/tpm_crb_ffa.h @@ -0,0 +1,25 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) 2024 Arm Ltd. + * + * This device driver implements the TPM CRB start method + * as defined in the TPM Service Command Response Buffer + * Interface Over FF-A (DEN0138). + */ +#ifndef _TPM_CRB_FFA_H +#define _TPM_CRB_FFA_H + +#if IS_ENABLED(CONFIG_TCG_ARM_CRB_FFA) +int tpm_crb_ffa_init(void); +int tpm_crb_ffa_get_interface_version(u16 *major, u16 *minor); +int tpm_crb_ffa_start(int request_type, int locality); +#else +static inline int tpm_crb_ffa_init(void) { return 0; } +static inline int tpm_crb_ffa_get_interface_version(u16 *major, u16 *minor) { return 0; } +static inline int tpm_crb_ffa_start(int request_type, int locality) { return 0; } +#endif + +#define CRB_FFA_START_TYPE_COMMAND 0 +#define CRB_FFA_START_TYPE_LOCALITY_REQUEST 1 + +#endif
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 <stuart.yoder@arm.com> --- drivers/char/tpm/Kconfig | 9 + drivers/char/tpm/Makefile | 1 + drivers/char/tpm/tpm_crb_ffa.c | 348 +++++++++++++++++++++++++++++++++ drivers/char/tpm/tpm_crb_ffa.h | 25 +++ 4 files changed, 383 insertions(+) create mode 100644 drivers/char/tpm/tpm_crb_ffa.c create mode 100644 drivers/char/tpm/tpm_crb_ffa.h