SPM: Introduce SPRT C host library

Change-Id: If57ec9cc0791f49d9ade83dff9d24ef9047963a8
Co-authored-by: Jean-Paul Etienne <jean-paul.etienne@arm.com>
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>

include/lib/sprt/sprt_common.h

+/*
+ * Copyright (c) 2018, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef SPRT_COMMON_H
+#define SPRT_COMMON_H
+
+#define SPRT_MAX_MSG_ARGS	6
+
+/*
+ * Message types supported.
+ */
+#define SPRT_MSG_TYPE_SERVICE_HANDLE_OPEN		1
+#define SPRT_MSG_TYPE_SERVICE_HANDLE_CLOSE		2
+/* TODO: Add other types of SPRT messages. */
+#define SPRT_MSG_TYPE_SERVICE_TUN_REQUEST		10
+
+/*
+ * Struct that defines the layout of the fields corresponding to a request in
+ * shared memory.
+ */
+struct __attribute__((__packed__)) sprt_queue_entry_message {
+	uint32_t type;		/* Type of message (result of an SPCI call). */
+	uint16_t client_id;	/* SPCI client ID */
+	uint16_t service_handle;/* SPCI service handle */
+	uint32_t session_id;	/* Optional SPCI session ID */
+	uint32_t token;		/* SPCI request token */
+	uint64_t args[SPRT_MAX_MSG_ARGS];
+};
+
+#define SPRT_QUEUE_ENTRY_MSG_SIZE	(sizeof(struct sprt_queue_entry_message))
+
+#define SPRT_QUEUE_NUM_BLOCKING		0
+#define SPRT_QUEUE_NUM_NON_BLOCKING	1
+
+#endif /* SPRT_COMMON_H */

include/lib/sprt/sprt_host.h

+/*
+ * Copyright (c) 2018, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+#ifndef SPRT_HOST_H
+#define SPRT_HOST_H
+
+#include <stddef.h>
+
+#include "sprt_common.h"
+
+/*
+ * Initialize the specified buffer to be used by SPM.
+ */
+void sprt_initialize_queues(void *buffer_base, size_t buffer_size);
+
+/*
+ * Push a message to the queue number `queue_num` in a buffer that has been
+ * initialized by `sprt_initialize_queues`.
+ */
+int sprt_push_message(void *buffer_base,
+		      const struct sprt_queue_entry_message *message,
+		      int queue_num);
+
+#endif /* SPRT_HOST_H */

lib/sprt/sprt_host.c

+/*
+ * Copyright (c) 2018, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <errno.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#include "sprt_common.h"
+#include "sprt_queue.h"
+
+void sprt_initialize_queues(void *buffer_base, size_t buffer_size)
+{
+	/* Initialize queue for blocking messages */
+
+	void *blocking_base = buffer_base;
+	uint32_t blocking_num = 4U;
+	size_t blocking_size = SPRT_QUEUE_HEADER_SIZE +
+			       SPRT_QUEUE_ENTRY_MSG_SIZE * blocking_num;
+
+	sprt_queue_init(blocking_base, blocking_num, SPRT_QUEUE_ENTRY_MSG_SIZE);
+
+	/* Initialize queue for non-blocking messages */
+
+	void *non_blocking_base = (void *)((uintptr_t)blocking_base + blocking_size);
+	size_t non_blocking_size = buffer_size - blocking_size;
+	uint32_t non_blocking_num = (non_blocking_size - SPRT_QUEUE_HEADER_SIZE) /
+		SPRT_QUEUE_ENTRY_MSG_SIZE;
+
+	sprt_queue_init(non_blocking_base, non_blocking_num, SPRT_QUEUE_ENTRY_MSG_SIZE);
+}
+
+int sprt_push_message(void *buffer_base,
+		      const struct sprt_queue_entry_message *message,
+		      int queue_num)
+{
+	struct sprt_queue *q = buffer_base;
+
+	while (queue_num-- > 0) {
+		uintptr_t next_addr = (uintptr_t)q + sizeof(struct sprt_queue) +
+				      q->entry_num * q->entry_size;
+		q = (struct sprt_queue *) next_addr;
+	}
+
+	return sprt_queue_push(q, message);
+}

lib/sprt/sprt_host.mk

+#
+# Copyright (c) 2018, Arm Limited. All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+#
+
+SPRT_LIB_SOURCES	:=	$(addprefix lib/sprt/,			\
+					sprt_host.c			\
+					sprt_queue.c)
+
+SPRT_LIB_INCLUDES	:=	-Iinclude/lib/sprt/

lib/sprt/sprt_queue.c

+/*
+ * Copyright (c) 2018, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+#include <errno.h>
+#include <stdint.h>
+#include <string.h>
+
+#include "sprt_queue.h"
+
+void sprt_queue_init(void *queue_base, uint32_t entry_num, uint32_t entry_size)
+{
+	assert(queue_base != NULL);
+	assert(entry_size > 0U);
+	assert(entry_num > 0U);
+
+	struct sprt_queue *queue = (struct sprt_queue *)queue_base;
+
+	queue->entry_num = entry_num;
+	queue->entry_size = entry_size;
+	queue->idx_write = 0U;
+	queue->idx_read = 0U;
+
+	memset(queue->data, 0, entry_num * entry_size);
+}
+
+int sprt_queue_is_empty(void *queue_base)
+{
+	assert(queue_base != NULL);
+
+	struct sprt_queue *queue = (struct sprt_queue *)queue_base;
+
+	return (queue->idx_write == queue->idx_read);
+}
+
+int sprt_queue_is_full(void *queue_base)
+{
+	assert(queue_base != NULL);
+
+	struct sprt_queue *queue = (struct sprt_queue *)queue_base;
+
+	uint32_t idx_next_write = (queue->idx_write + 1) % queue->entry_num;
+
+	return (idx_next_write == queue->idx_read);
+}
+
+int sprt_queue_push(void *queue_base, const void *entry)
+{
+	assert(entry != NULL);
+	assert(queue_base != NULL);
+
+	if (sprt_queue_is_full(queue_base) != 0) {
+		return -ENOMEM;
+	}
+
+	struct sprt_queue *queue = (struct sprt_queue *)queue_base;
+
+	uint8_t *dst_entry = &queue->data[queue->entry_size * queue->idx_write];
+
+	memcpy(dst_entry, entry, queue->entry_size);
+
+	/*
+	 * Make sure that the message data is visible before increasing the
+	 * counter of available messages.
+	 */
+	__asm__ volatile("dmb st" ::: "memory");
+
+	queue->idx_write = (queue->idx_write + 1) % queue->entry_num;
+
+	__asm__ volatile("dmb st" ::: "memory");
+
+	return 0;
+}
+
+int sprt_queue_pop(void *queue_base, void *entry)
+{
+	assert(entry != NULL);
+	assert(queue_base != NULL);
+
+	if (sprt_queue_is_empty(queue_base) != 0) {
+		return -ENOENT;
+	}
+
+	struct sprt_queue *queue = (struct sprt_queue *)queue_base;
+
+	uint8_t *src_entry = &queue->data[queue->entry_size * queue->idx_read];
+
+	memcpy(entry, src_entry, queue->entry_size);
+
+	/*
+	 * Make sure that the message data is visible before increasing the
+	 * counter of read messages.
+	 */
+	__asm__ volatile("dmb st" ::: "memory");
+
+	queue->idx_read = (queue->idx_read + 1) % queue->entry_num;
+
+	__asm__ volatile("dmb st" ::: "memory");
+
+	return 0;
+}

lib/sprt/sprt_queue.h

+/*
+ * Copyright (c) 2018, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef SPRT_QUEUE_H
+#define SPRT_QUEUE_H
+
+#include <stdint.h>
+
+/* Struct that defines a queue. Not to be used directly. */
+struct __attribute__((__packed__)) sprt_queue {
+	uint32_t entry_num;	/* Number of entries */
+	uint32_t entry_size;	/* Size of an entry */
+	uint32_t idx_write;	/* Index of first empty entry */
+	uint32_t idx_read;	/* Index of first entry to read */
+	uint8_t  data[0];	/* Start of data */
+};
+
+#define SPRT_QUEUE_HEADER_SIZE	(sizeof(struct sprt_queue))
+
+/*
+ * Initializes a memory region to be used as a queue of the given number of
+ * entries with the specified size.
+ */
+void sprt_queue_init(void *queue_base, uint32_t entry_num, uint32_t entry_size);
+
+/* Returns 1 if the queue is empty, 0 otherwise */
+int sprt_queue_is_empty(void *queue_base);
+
+/* Returns 1 if the queue is full, 0 otherwise */
+int sprt_queue_is_full(void *queue_base);
+
+/*
+ * Pushes a new entry intro the queue. Returns 0 on success, -ENOMEM if the
+ * queue is full.
+ */
+int sprt_queue_push(void *queue_base, const void *entry);
+
+/*
+ * Pops an entry from the queue. Returns 0 on success, -ENOENT if the queue is
+ * empty.
+ */
+int sprt_queue_pop(void *queue_base, void *entry);
+
+#endif /* SPRT_QUEUE_H */

services/std_svc/spm/spm.mk

@@ -11,6 +11,8 @@ ifneq (${ARCH},aarch64)
         $(error "Error: SPM is only supported on aarch64.")
 endif
 
+include lib/sprt/sprt_host.mk
+
 SPM_SOURCES	:=	$(addprefix services/std_svc/spm/,	\
 			${ARCH}/spm_helpers.S			\
 			${ARCH}/spm_shim_exceptions.S		\
@@ -18,8 +20,10 @@ SPM_SOURCES	:=	$(addprefix services/std_svc/spm/,	\
 			sp_xlat.c				\
 			spci.c					\
 			spm_main.c				\
-			sprt.c)
+			sprt.c)					\
+			${SPRT_LIB_SOURCES}
 
+INCLUDES	+=	${SPRT_LIB_INCLUDES}
 
 # Force SMC Calling Convention 2 when using SPM
 SMCCC_MAJOR_VERSION	:=	2