optee: add FF-A support

Adds support for using FF-A [1] as transport to the OP-TEE driver.

Introduces struct optee_msg_param_fmem which carries all information
needed when OP-TEE is calling FFA_MEM_RETRIEVE_REQ to get the shared
memory reference mapped by the hypervisor in S-EL2. Register usage is
also updated to include the information needed.

The FF-A part of this driver is enabled if CONFIG_ARM_FFA_TRANSPORT is
enabled.

[1] https://developer.arm.com/documentation/den0077/latestAcked-by: Sumit Garg <sumit.garg@linaro.org>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>

drivers/tee/optee/Makefile

@@ -6,6 +6,7 @@ optee-objs += rpc.o
 optee-objs += supp.o
 optee-objs += device.o
 optee-objs += smc_abi.o
+optee-objs += ffa_abi.o
 
 # for tracing framework to find optee_trace.h
 CFLAGS_smc_abi.o := -I$(src)

drivers/tee/optee/call.c

@@ -107,11 +107,20 @@ static struct optee_session *find_session(struct optee_context_data *ctxdata,
 struct tee_shm *optee_get_msg_arg(struct tee_context *ctx, size_t num_params,
 				  struct optee_msg_arg **msg_arg)
 {
+	struct optee *optee = tee_get_drvdata(ctx->teedev);
+	size_t sz = OPTEE_MSG_GET_ARG_SIZE(num_params);
 	struct tee_shm *shm;
 	struct optee_msg_arg *ma;
 
-	shm = tee_shm_alloc(ctx, OPTEE_MSG_GET_ARG_SIZE(num_params),
-			    TEE_SHM_MAPPED | TEE_SHM_PRIV);
+	/*
+	 * rpc_arg_count is set to the number of allocated parameters in
+	 * the RPC argument struct if a second MSG arg struct is expected.
+	 * The second arg struct will then be used for RPC.
+	 */
+	if (optee->rpc_arg_count)
+		sz += OPTEE_MSG_GET_ARG_SIZE(optee->rpc_arg_count);
+
+	shm = tee_shm_alloc(ctx, sz, TEE_SHM_MAPPED | TEE_SHM_PRIV);
 	if (IS_ERR(shm))
 		return shm;
 

drivers/tee/optee/core.c

@@ -172,6 +172,9 @@ void optee_remove_common(struct optee *optee)
 	mutex_destroy(&optee->call_queue.mutex);
 }
 
+static int smc_abi_rc;
+static int ffa_abi_rc;
+
 static int optee_core_init(void)
 {
 	/*
@@ -184,13 +187,22 @@ static int optee_core_init(void)
 	if (is_kdump_kernel())
 		return -ENODEV;
 
-	return optee_smc_abi_register();
+	smc_abi_rc = optee_smc_abi_register();
+	ffa_abi_rc = optee_ffa_abi_register();
+
+	/* If both failed there's no point with this module */
+	if (smc_abi_rc && ffa_abi_rc)
+		return smc_abi_rc;
+	return 0;
 }
 module_init(optee_core_init);
 
 static void optee_core_exit(void)
 {
-	optee_smc_abi_unregister();
+	if (!smc_abi_rc)
+		optee_smc_abi_unregister();
+	if (!ffa_abi_rc)
+		optee_ffa_abi_unregister();
 }
 module_exit(optee_core_exit);
 

drivers/tee/optee/optee_ffa.h

+/* SPDX-License-Identifier: BSD-2-Clause */
+/*
+ * Copyright (c) 2019-2021, Linaro Limited
+ */
+
+/*
+ * This file is exported by OP-TEE and is kept in sync between secure world
+ * and normal world drivers. We're using ARM FF-A 1.0 specification.
+ */
+
+#ifndef __OPTEE_FFA_H
+#define __OPTEE_FFA_H
+
+#include <linux/arm_ffa.h>
+
+/*
+ * 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
+ */
+
+#define OPTEE_FFA_VERSION_MAJOR	1
+#define OPTEE_FFA_VERSION_MINOR	0
+
+#define OPTEE_FFA_BLOCKING_CALL(id)	(id)
+#define OPTEE_FFA_YIELDING_CALL_BIT	31
+#define OPTEE_FFA_YIELDING_CALL(id)	((id) | BIT(OPTEE_FFA_YIELDING_CALL_BIT))
+
+/*
+ * Returns the API version implemented, currently follows the FF-A version.
+ * Call register usage:
+ * w3:    Service ID, OPTEE_FFA_GET_API_VERSION
+ * w4-w7: Not used (MBZ)
+ *
+ * Return register usage:
+ * w3:    OPTEE_FFA_VERSION_MAJOR
+ * w4:    OPTEE_FFA_VERSION_MINOR
+ * w5-w7: Not used (MBZ)
+ */
+#define OPTEE_FFA_GET_API_VERSION	OPTEE_FFA_BLOCKING_CALL(0)
+
+/*
+ * Returns the revision of OP-TEE.
+ *
+ * Used by non-secure world to figure out which version of the Trusted OS
+ * is installed. Note that the returned revision is the revision of the
+ * Trusted OS, not of the API.
+ *
+ * Call register usage:
+ * w3:    Service ID, OPTEE_FFA_GET_OS_VERSION
+ * w4-w7: Unused (MBZ)
+ *
+ * Return register usage:
+ * w3:    CFG_OPTEE_REVISION_MAJOR
+ * w4:    CFG_OPTEE_REVISION_MINOR
+ * w5:    TEE_IMPL_GIT_SHA1 (or zero if not supported)
+ */
+#define OPTEE_FFA_GET_OS_VERSION	OPTEE_FFA_BLOCKING_CALL(1)
+
+/*
+ * Exchange capabilities between normal world and secure world.
+ *
+ * Currently there are no defined capabilities. When features are added new
+ * capabilities may be added.
+ *
+ * Call register usage:
+ * w3:    Service ID, OPTEE_FFA_EXCHANGE_CAPABILITIES
+ * w4-w7: Note used (MBZ)
+ *
+ * Return register usage:
+ * w3:    Error code, 0 on success
+ * w4:    Bit[7:0]:  Number of parameters needed for RPC to be supplied
+ *                   as the second MSG arg struct for
+ *                   OPTEE_FFA_YIELDING_CALL_WITH_ARG.
+ *        Bit[31:8]: Reserved (MBZ)
+ * w5-w7: Note used (MBZ)
+ */
+#define OPTEE_FFA_EXCHANGE_CAPABILITIES OPTEE_FFA_BLOCKING_CALL(2)
+
+/*
+ * Unregister shared memory
+ *
+ * Call register usage:
+ * w3:    Service ID, OPTEE_FFA_YIELDING_CALL_UNREGISTER_SHM
+ * w4:    Shared memory handle, lower bits
+ * w5:    Shared memory handle, higher bits
+ * w6-w7: Not used (MBZ)
+ *
+ * Return register usage:
+ * w3:    Error code, 0 on success
+ * w4-w7: Note used (MBZ)
+ */
+#define OPTEE_FFA_UNREGISTER_SHM	OPTEE_FFA_BLOCKING_CALL(3)
+
+/*
+ * Call with struct optee_msg_arg as argument in the supplied shared memory
+ * with a zero internal offset and normal cached memory attributes.
+ * Register usage:
+ * w3:    Service ID, OPTEE_FFA_YIELDING_CALL_WITH_ARG
+ * w4:    Lower 32 bits of a 64-bit Shared memory handle
+ * w5:    Upper 32 bits of a 64-bit Shared memory handle
+ * w6:    Offset into shared memory pointing to a struct optee_msg_arg
+ *	  right after the parameters of this struct (at offset
+ *	  OPTEE_MSG_GET_ARG_SIZE(num_params) follows a struct optee_msg_arg
+ *	  for RPC, this struct has reserved space for the number of RPC
+ *	  parameters as returned by OPTEE_FFA_EXCHANGE_CAPABILITIES.
+ * w7:    Not used (MBZ)
+ * Resume from RPC. Register usage:
+ * w3:    Service ID, OPTEE_FFA_YIELDING_CALL_RESUME
+ * w4-w6: Not used (MBZ)
+ * w7:    Resume info
+ *
+ * Normal return (yielding call is completed). Register usage:
+ * w3:    Error code, 0 on success
+ * w4:    OPTEE_FFA_YIELDING_CALL_RETURN_DONE
+ * w5-w7: Not used (MBZ)
+ *
+ * RPC interrupt return (RPC from secure world). Register usage:
+ * w3:    Error code == 0
+ * w4:    Any defined RPC code but OPTEE_FFA_YIELDING_CALL_RETURN_DONE
+ * w5-w6: Not used (MBZ)
+ * w7:    Resume info
+ *
+ * Possible error codes in register w3:
+ * 0:                       Success
+ * FFA_DENIED:              w4 isn't one of OPTEE_FFA_YIELDING_CALL_START
+ *                          OPTEE_FFA_YIELDING_CALL_RESUME
+ *
+ * Possible error codes for OPTEE_FFA_YIELDING_CALL_START,
+ * FFA_BUSY:               Number of OP-TEE OS threads exceeded,
+ *                         try again later
+ * FFA_DENIED:             RPC shared memory object not found
+ * FFA_INVALID_PARAMETER:  Bad shared memory handle or offset into the memory
+ *
+ * Possible error codes for OPTEE_FFA_YIELDING_CALL_RESUME
+ * FFA_INVALID_PARAMETER:  Bad resume info
+ */
+#define OPTEE_FFA_YIELDING_CALL_WITH_ARG	OPTEE_FFA_YIELDING_CALL(0)
+#define OPTEE_FFA_YIELDING_CALL_RESUME		OPTEE_FFA_YIELDING_CALL(1)
+
+#define OPTEE_FFA_YIELDING_CALL_RETURN_DONE		0
+#define OPTEE_FFA_YIELDING_CALL_RETURN_RPC_CMD		1
+#define OPTEE_FFA_YIELDING_CALL_RETURN_INTERRUPT	2
+
+#endif /*__OPTEE_FFA_H*/

drivers/tee/optee/optee_msg.h

@@ -28,6 +28,9 @@
 #define OPTEE_MSG_ATTR_TYPE_RMEM_INPUT		0x5
 #define OPTEE_MSG_ATTR_TYPE_RMEM_OUTPUT		0x6
 #define OPTEE_MSG_ATTR_TYPE_RMEM_INOUT		0x7
+#define OPTEE_MSG_ATTR_TYPE_FMEM_INPUT		OPTEE_MSG_ATTR_TYPE_RMEM_INPUT
+#define OPTEE_MSG_ATTR_TYPE_FMEM_OUTPUT		OPTEE_MSG_ATTR_TYPE_RMEM_OUTPUT
+#define OPTEE_MSG_ATTR_TYPE_FMEM_INOUT		OPTEE_MSG_ATTR_TYPE_RMEM_INOUT
 #define OPTEE_MSG_ATTR_TYPE_TMEM_INPUT		0x9
 #define OPTEE_MSG_ATTR_TYPE_TMEM_OUTPUT		0xa
 #define OPTEE_MSG_ATTR_TYPE_TMEM_INOUT		0xb
@@ -96,6 +99,8 @@
  */
 #define OPTEE_MSG_NONCONTIG_PAGE_SIZE		4096
 
+#define OPTEE_MSG_FMEM_INVALID_GLOBAL_ID	0xffffffffffffffff
+
 /**
  * struct optee_msg_param_tmem - temporary memory reference parameter
  * @buf_ptr:	Address of the buffer
@@ -127,6 +132,23 @@ struct optee_msg_param_rmem {
 	u64 shm_ref;
 };
 
+/**
+ * struct optee_msg_param_fmem - ffa memory reference parameter
+ * @offs_lower:	   Lower bits of offset into shared memory reference
+ * @offs_upper:	   Upper bits of offset into shared memory reference
+ * @internal_offs: Internal offset into the first page of shared memory
+ *		   reference
+ * @size:	   Size of the buffer
+ * @global_id:	   Global identifier of Shared memory
+ */
+struct optee_msg_param_fmem {
+	u32 offs_low;
+	u16 offs_high;
+	u16 internal_offs;
+	u64 size;
+	u64 global_id;
+};
+
 /**
  * struct optee_msg_param_value - opaque value parameter
  *
@@ -143,13 +165,15 @@ struct optee_msg_param_value {
  * @attr:	attributes
  * @tmem:	parameter by temporary memory reference
  * @rmem:	parameter by registered memory reference
+ * @fmem:	parameter by ffa registered memory reference
  * @value:	parameter by opaque value
  * @octets:	parameter by octet string
  *
  * @attr & OPTEE_MSG_ATTR_TYPE_MASK indicates if tmem, rmem or value is used in
  * the union. OPTEE_MSG_ATTR_TYPE_VALUE_* indicates value or octets,
  * OPTEE_MSG_ATTR_TYPE_TMEM_* indicates @tmem and
- * OPTEE_MSG_ATTR_TYPE_RMEM_* indicates @rmem,
+ * OPTEE_MSG_ATTR_TYPE_RMEM_* or the alias PTEE_MSG_ATTR_TYPE_FMEM_* indicates
+ * @rmem or @fmem depending on the conduit.
  * OPTEE_MSG_ATTR_TYPE_NONE indicates that none of the members are used.
  */
 struct optee_msg_param {
@@ -157,6 +181,7 @@ struct optee_msg_param {
 	union {
 		struct optee_msg_param_tmem tmem;
 		struct optee_msg_param_rmem rmem;
+		struct optee_msg_param_fmem fmem;
 		struct optee_msg_param_value value;
 		u8 octets[24];
 	} u;

drivers/tee/optee/optee_private.h

@@ -7,6 +7,7 @@
 #define OPTEE_PRIVATE_H
 
 #include <linux/arm-smccc.h>
+#include <linux/rhashtable.h>
 #include <linux/semaphore.h>
 #include <linux/tee_drv.h>
 #include <linux/types.h>
@@ -22,6 +23,7 @@
 #define TEEC_ERROR_NOT_SUPPORTED	0xFFFF000A
 #define TEEC_ERROR_COMMUNICATION	0xFFFF000E
 #define TEEC_ERROR_OUT_OF_MEMORY	0xFFFF000C
+#define TEEC_ERROR_BUSY			0xFFFF000D
 #define TEEC_ERROR_SHORT_BUFFER		0xFFFF0010
 
 #define TEEC_ORIGIN_COMMS		0x00000002
@@ -73,19 +75,28 @@ struct optee_supp {
 	struct completion reqs_c;
 };
 
-/**
- * struct optee_smc - SMC ABI specifics
- * @invoke_fn:		function to issue smc or hvc
- * @memremaped_shm	virtual address of memory in shared memory pool
- * @sec_caps:		secure world capabilities defined by
- *			OPTEE_SMC_SEC_CAP_* in optee_smc.h
- */
 struct optee_smc {
 	optee_invoke_fn *invoke_fn;
 	void *memremaped_shm;
 	u32 sec_caps;
 };
 
+/**
+ * struct optee_ffa_data -  FFA communication struct
+ * @ffa_dev		FFA device, contains the destination id, the id of
+ *			OP-TEE in secure world
+ * @ffa_ops		FFA operations
+ * @mutex		Serializes access to @global_ids
+ * @global_ids		FF-A shared memory global handle translation
+ */
+struct optee_ffa {
+	struct ffa_device *ffa_dev;
+	const struct ffa_dev_ops *ffa_ops;
+	/* Serializes access to @global_ids */
+	struct mutex mutex;
+	struct rhashtable global_ids;
+};
+
 struct optee;
 
 /**
@@ -116,11 +127,13 @@ struct optee_ops {
  *			world
  * @teedev:		client device
  * @smc:		specific to SMC ABI
+ * @ffa:		specific to FF-A ABI
  * @call_queue:		queue of threads waiting to call @invoke_fn
  * @wait_queue:		queue of threads from secure world waiting for a
  *			secure world sync object
  * @supp:		supplicant synchronization struct for RPC to supplicant
  * @pool:		shared memory pool
+ * @rpc_arg_count:	If > 0 number of RPC parameters to make room for
  * @scan_bus_done	flag if device registation was already done.
  * @scan_bus_wq		workqueue to scan optee bus and register optee drivers
  * @scan_bus_work	workq to scan optee bus and register optee drivers
@@ -129,11 +142,15 @@ struct optee {
 	struct tee_device *supp_teedev;
 	struct tee_device *teedev;
 	const struct optee_ops *ops;
-	struct optee_smc smc;
+	union {
+		struct optee_smc smc;
+		struct optee_ffa ffa;
+	};
 	struct optee_call_queue call_queue;
 	struct optee_wait_queue wait_queue;
 	struct optee_supp supp;
 	struct tee_shm_pool *pool;
+	unsigned int rpc_arg_count;
 	bool   scan_bus_done;
 	struct workqueue_struct *scan_bus_wq;
 	struct work_struct scan_bus_work;
@@ -266,5 +283,7 @@ static inline void reg_pair_from_64(u32 *reg0, u32 *reg1, u64 val)
 /* Registration of the ABIs */
 int optee_smc_abi_register(void);
 void optee_smc_abi_unregister(void);
+int optee_ffa_abi_register(void);
+void optee_ffa_abi_unregister(void);
 
 #endif /*OPTEE_PRIVATE_H*/