Merge: Update support for Arm FF-A firmware interface.

MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-10/-/merge_requests/1208

JIRA: https://issues.redhat.com/browse/RHEL-102692

## Summary of Changes

The following series updates support for Arm FF-A firmware interface.

Signed-off-by: Marcin Juszkiewicz <mjuszkiewicz@redhat.com>

Approved-by: Lucas Zampieri <lzampier@redhat.com>
Approved-by: Mark Salter <msalter@redhat.com>
Approved-by: CKI KWF Bot <cki-ci-bot+kwf-gitlab-com@redhat.com>

Merged-by: Scott Weaver <scweaver@redhat.com>

Author: swvrrh

Documentation/security/tpm/index.rst

@@ -10,3 +10,4 @@ Trusted Platform Module documentation
    tpm_vtpm_proxy
    xen-tpmfront
    tpm_ftpm_tee
+   tpm_ffa_crb

Documentation/security/tpm/tpm_ffa_crb.rst

@@ -0,0 +1,65 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+========================
+TPM CRB over FF-A Driver
+========================
+
+The TPM Command Response Buffer (CRB) interface is a standard TPM interface
+defined in the TCG PC Client Platform TPM Profile (PTP) Specification [1]_.
+The CRB provides a structured set of control registers a client uses when
+interacting with a TPM as well as a data buffer for storing TPM commands and
+responses. A CRB interface can be implemented in:
+
+- hardware registers in a discrete TPM chip
+
+- in memory for a TPM running in isolated environment where shared memory
+  allows a client to interact with the TPM
+
+The Firmware Framework for Arm A-profile (FF-A) [2]_ is a specification
+that defines interfaces and protocols for the following purposes:
+
+- Compartmentalize firmware into software partitions that run in the Arm
+  Secure world environment (also know as TrustZone)
+
+- Provide a standard interface for software components in the Non-secure
+  state, for example OS and Hypervisors, to communicate with this firmware.
+
+A TPM can be implemented as an FF-A secure service.  This could be a firmware
+TPM or could potentially be a TPM service that acts as a proxy to a discrete
+TPM chip. An FF-A based TPM abstracts hardware details (e.g. bus controller
+and chip selects) away from the OS and can protect locality 4 from access
+by an OS.  The TCG-defined CRB interface is used by clients to interact
+with the TPM service.
+
+The Arm TPM Service Command Response Buffer Interface Over FF-A [3]_
+specification defines FF-A messages that can be used by a client to signal
+when updates have been made to the CRB.
+
+How the Linux CRB driver interacts with FF-A is summarized below:
+
+- The tpm_crb_ffa driver registers with the FF-A subsystem in the kernel
+  with an architected TPM service UUID defined in the CRB over FF-A spec.
+
+- If a TPM service is discovered by FF-A, the probe() function in the
+  tpm_crb_ffa driver runs, and the driver initializes.
+
+- The probing and initialization of the Linux CRB driver is triggered
+  by the discovery of a TPM advertised via ACPI.  The CRB driver can
+  detect the type of TPM through the ACPI 'start' method.  The start
+  method for Arm FF-A was defined in TCG ACPI v1.4 [4]_.
+
+- When the CRB driver performs its normal functions such as signaling 'start'
+  and locality request/relinquish it invokes the tpm_crb_ffa_start() funnction
+  in the tpm_crb_ffa driver which handles the FF-A messaging to the TPM.
+
+References
+==========
+
+.. [1] **TCG PC Client Platform TPM Profile (PTP) Specification**
+   https://trustedcomputinggroup.org/resource/pc-client-platform-tpm-profile-ptp-specification/
+.. [2] **Arm Firmware Framework for Arm A-profile (FF-A)**
+   https://developer.arm.com/documentation/den0077/latest/
+.. [3] **Arm TPM Service Command Response Buffer Interface Over FF-A**
+   https://developer.arm.com/documentation/den0138/latest/
+.. [4] **TCG ACPI Specification**
+   https://trustedcomputinggroup.org/resource/tcg-acpi-specification/

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 && TCG_CRB
+	default TCG_CRB
+	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

drivers/char/tpm/Makefile

@@ -42,6 +42,7 @@ 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-$(CONFIG_TCG_FTPM_TEE) += tpm_ftpm_tee.o
 obj-$(CONFIG_TCG_SVSM) += tpm_svsm.o

drivers/char/tpm/tpm_crb.c

@@ -19,6 +19,7 @@
 #ifdef CONFIG_ARM64
 #include <linux/arm-smccc.h>
 #endif
+#include "tpm_crb_ffa.h"
 #include "tpm.h"
 
 #define ACPI_SIG_TPM2 "TPM2"
@@ -100,6 +101,8 @@ struct crb_priv {
 	u32 smc_func_id;
 	u32 __iomem *pluton_start_addr;
 	u32 __iomem *pluton_reply_addr;
+	u8 ffa_flags;
+	u8 ffa_attributes;
 };
 
 struct tpm2_crb_smc {
@@ -110,6 +113,14 @@ struct tpm2_crb_smc {
 	u32 smc_func_id;
 };
 
+/* CRB over FFA start method parameters in TCG2 ACPI table */
+struct tpm2_crb_ffa {
+	u8 flags;
+	u8 attributes;
+	u16 partition_id;
+	u8 reserved[8];
+};
+
 struct tpm2_crb_pluton {
 	u64 start_addr;
 	u64 reply_addr;
@@ -122,7 +133,8 @@ static inline bool tpm_crb_has_idle(u32 start_method)
 {
 	return !(start_method == ACPI_TPM2_START_METHOD ||
 	       start_method == ACPI_TPM2_COMMAND_BUFFER_WITH_START_METHOD ||
-	       start_method == ACPI_TPM2_COMMAND_BUFFER_WITH_ARM_SMC);
+	       start_method == ACPI_TPM2_COMMAND_BUFFER_WITH_ARM_SMC ||
+	       start_method == ACPI_TPM2_CRB_WITH_ARM_FFA);
 }
 
 static bool crb_wait_for_reg_32(u32 __iomem *reg, u32 mask, u32 value,
@@ -261,13 +273,20 @@ static int crb_cmd_ready(struct tpm_chip *chip)
 static int __crb_request_locality(struct device *dev,
 				  struct crb_priv *priv, int loc)
 {
-	u32 value = CRB_LOC_STATE_LOC_ASSIGNED |
-		    CRB_LOC_STATE_TPM_REG_VALID_STS;
+	u32 value = CRB_LOC_STATE_LOC_ASSIGNED | CRB_LOC_STATE_TPM_REG_VALID_STS;
+	int rc;
 
 	if (!priv->regs_h)
 		return 0;
 
 	iowrite32(CRB_LOC_CTRL_REQUEST_ACCESS, &priv->regs_h->loc_ctrl);
+
+	if (priv->sm == ACPI_TPM2_CRB_WITH_ARM_FFA) {
+		rc = tpm_crb_ffa_start(CRB_FFA_START_TYPE_LOCALITY_REQUEST, loc);
+		if (rc)
+			return rc;
+	}
+
 	if (!crb_wait_for_reg_32(&priv->regs_h->loc_state, value, value,
 				 TPM2_TIMEOUT_C)) {
 		dev_warn(dev, "TPM_LOC_STATE_x.requestAccess timed out\n");
@@ -287,14 +306,21 @@ static int crb_request_locality(struct tpm_chip *chip, int loc)
 static int __crb_relinquish_locality(struct device *dev,
 				     struct crb_priv *priv, int loc)
 {
-	u32 mask = CRB_LOC_STATE_LOC_ASSIGNED |
-		   CRB_LOC_STATE_TPM_REG_VALID_STS;
+	u32 mask = CRB_LOC_STATE_LOC_ASSIGNED | CRB_LOC_STATE_TPM_REG_VALID_STS;
 	u32 value = CRB_LOC_STATE_TPM_REG_VALID_STS;
+	int rc;
 
 	if (!priv->regs_h)
 		return 0;
 
 	iowrite32(CRB_LOC_CTRL_RELINQUISH, &priv->regs_h->loc_ctrl);
+
+	if (priv->sm == ACPI_TPM2_CRB_WITH_ARM_FFA) {
+		rc = tpm_crb_ffa_start(CRB_FFA_START_TYPE_LOCALITY_REQUEST, loc);
+		if (rc)
+			return rc;
+	}
+
 	if (!crb_wait_for_reg_32(&priv->regs_h->loc_state, mask, value,
 				 TPM2_TIMEOUT_C)) {
 		dev_warn(dev, "TPM_LOC_STATE_x.Relinquish timed out\n");
@@ -443,6 +469,11 @@ static int crb_send(struct tpm_chip *chip, u8 *buf, size_t len)
 		rc = tpm_crb_smc_start(&chip->dev, priv->smc_func_id);
 	}
 
+	if (priv->sm == ACPI_TPM2_CRB_WITH_ARM_FFA) {
+		iowrite32(CRB_START_INVOKE, &priv->regs_t->ctrl_start);
+		rc = tpm_crb_ffa_start(CRB_FFA_START_TYPE_COMMAND, chip->locality);
+	}
+
 	if (rc)
 		return rc;
 
@@ -452,13 +483,20 @@ static int crb_send(struct tpm_chip *chip, u8 *buf, size_t len)
 static void crb_cancel(struct tpm_chip *chip)
 {
 	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
+	int rc;
 
 	iowrite32(CRB_CANCEL_INVOKE, &priv->regs_t->ctrl_cancel);
 
 	if ((priv->sm == ACPI_TPM2_START_METHOD ||
 	     priv->sm == ACPI_TPM2_COMMAND_BUFFER_WITH_START_METHOD) &&
 	     crb_do_acpi_start(chip))
 		dev_err(&chip->dev, "ACPI Start failed\n");
+
+	if (priv->sm == ACPI_TPM2_CRB_WITH_ARM_FFA) {
+		rc = tpm_crb_ffa_start(CRB_FFA_START_TYPE_COMMAND, chip->locality);
+		if (rc)
+			dev_err(&chip->dev, "FF-A Start failed\n");
+	}
 }
 
 static bool crb_req_canceled(struct tpm_chip *chip, u8 status)
@@ -616,6 +654,7 @@ static int crb_map_io(struct acpi_device *device, struct crb_priv *priv,
 	 * stuff that puts the control area outside the ACPI IO region.
 	 */
 	if (priv->sm == ACPI_TPM2_COMMAND_BUFFER ||
+	    priv->sm == ACPI_TPM2_CRB_WITH_ARM_FFA ||
 	    priv->sm == ACPI_TPM2_MEMORY_MAPPED) {
 		if (iores &&
 		    buf->control_address == iores->start +
@@ -737,6 +776,7 @@ static int crb_acpi_add(struct acpi_device *device)
 	struct tpm_chip *chip;
 	struct device *dev = &device->dev;
 	struct tpm2_crb_smc *crb_smc;
+	struct tpm2_crb_ffa *crb_ffa;
 	struct tpm2_crb_pluton *crb_pluton;
 	acpi_status status;
 	u32 sm;
@@ -775,6 +815,27 @@ static int crb_acpi_add(struct acpi_device *device)
 		priv->smc_func_id = crb_smc->smc_func_id;
 	}
 
+	if (sm == ACPI_TPM2_CRB_WITH_ARM_FFA) {
+		if (buf->header.length < (sizeof(*buf) + sizeof(*crb_ffa))) {
+			dev_err(dev,
+				FW_BUG "TPM2 ACPI table has wrong size %u for start method type %d\n",
+				buf->header.length,
+				ACPI_TPM2_CRB_WITH_ARM_FFA);
+			rc = -EINVAL;
+			goto out;
+		}
+		crb_ffa = ACPI_ADD_PTR(struct tpm2_crb_ffa, buf, sizeof(*buf));
+		priv->ffa_flags = crb_ffa->flags;
+		priv->ffa_attributes = crb_ffa->attributes;
+		rc = tpm_crb_ffa_init();
+		if (rc) {
+			/* If FF-A driver is not available yet, request probe retry */
+			if (rc == -ENOENT)
+				rc = -EPROBE_DEFER;
+			goto out;
+		}
+	}
+
 	if (sm == ACPI_TPM2_COMMAND_BUFFER_WITH_PLUTON) {
 		if (buf->header.length < (sizeof(*buf) + sizeof(*crb_pluton))) {
 			dev_err(dev,