tee: qcom: enable TEE_IOC_SHM_ALLOC ioctl

Enable userspace to allocate shared memory with QTEE. Since
QTEE handles shared memory as object, a wrapper is implemented
to represent tee_shm as an object. The shared memory identifier,
obtained through TEE_IOC_SHM_ALLOC, is transferred to the driver using
TEE_IOCTL_PARAM_ATTR_TYPE_OBJREF_INPUT/OUTPUT.

Tested-by: Neil Armstrong <[e-mail]>
Acked-by: Sumit Garg <[e-mail]>
Tested-by: Harshal Dev <[e-mail]>
Signed-off-by: Amirreza Zarrabi <[e-mail]>
Signed-off-by: Jens Wiklander <[e-mail]>

drivers/tee/qcomtee/Makefile

···
 qcomtee-objs += async.o
 qcomtee-objs += call.o
 qcomtee-objs += core.o
+qcomtee-objs += mem_obj.o
 qcomtee-objs += primordial_obj.o
 qcomtee-objs += shm.o
 qcomtee-objs += user_obj.o

drivers/tee/qcomtee/call.c

···
 		err =  qcomtee_user_param_to_object(&arg->o, param, ctx);
 	/* param is a QTEE object: */
 	else if (param->u.objref.flags & QCOMTEE_OBJREF_FLAG_TEE)
-		err =  qcomtee_context_find_qtee_object(&arg->o, param, ctx);
+		err = qcomtee_context_find_qtee_object(&arg->o, param, ctx);
+	/* param is a memory object: */
+	else if (param->u.objref.flags & QCOMTEE_OBJREF_FLAG_MEM)
+		err = qcomtee_memobj_param_to_object(&arg->o, param, ctx);
 
 	/*
 	 * For callback objects, call qcomtee_object_get() to keep a temporary
···
 		if (is_qcomtee_user_object(object))
 			return qcomtee_user_param_from_object(param, object,
 							      ctx);
+		/* object is a memory object: */
+		else if (is_qcomtee_memobj_object(object))
+			return qcomtee_memobj_param_from_object(param, object,
+							       ctx);
 
 		break;
 	case QCOMTEE_OBJECT_TYPE_TEE:

drivers/tee/qcomtee/mem_obj.c

···
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/firmware/qcom/qcom_scm.h>
+#include <linux/mm.h>
+
+#include "qcomtee.h"
+
+/**
+ * DOC: Memory and Mapping Objects
+ *
+ * QTEE uses memory objects for memory sharing with Linux.
+ * A memory object can be a standard dma_buf or a contiguous memory range,
+ * e.g., tee_shm. A memory object should support one operation: map. When
+ * invoked by QTEE, a mapping object is generated. A mapping object supports
+ * one operation: unmap.
+ *
+ *  (1) To map a memory object, QTEE invokes the primordial object with
+ *      %QCOMTEE_OBJECT_OP_MAP_REGION operation; see
+ *      qcomtee_primordial_obj_dispatch().
+ *  (2) To unmap a memory object, QTEE releases the mapping object which
+ *      calls qcomtee_mem_object_release().
+ *
+ * The map operation is implemented in the primordial object as a privileged
+ * operation instead of qcomtee_mem_object_dispatch(). Otherwise, on
+ * platforms without shm_bridge, a user can trick QTEE into writing to the
+ * kernel memory by passing a user object as a memory object and returning a
+ * random physical address as the result of the mapping request.
+ */
+
+struct qcomtee_mem_object {
+	struct qcomtee_object object;
+	struct tee_shm *shm;
+	/* QTEE requires these felids to be page aligned. */
+	phys_addr_t paddr; /* Physical address of range. */
+	size_t size; /* Size of the range. */
+};
+
+#define to_qcomtee_mem_object(o) \
+	container_of((o), struct qcomtee_mem_object, object)
+
+static struct qcomtee_object_operations qcomtee_mem_object_ops;
+
+/* Is it a memory object using tee_shm? */
+int is_qcomtee_memobj_object(struct qcomtee_object *object)
+{
+	return object != NULL_QCOMTEE_OBJECT &&
+	       typeof_qcomtee_object(object) == QCOMTEE_OBJECT_TYPE_CB &&
+	       object->ops == &qcomtee_mem_object_ops;
+}
+
+static int qcomtee_mem_object_dispatch(struct qcomtee_object_invoke_ctx *oic,
+				       struct qcomtee_object *object, u32 op,
+				       struct qcomtee_arg *args)
+{
+	return -EINVAL;
+}
+
+static void qcomtee_mem_object_release(struct qcomtee_object *object)
+{
+	struct qcomtee_mem_object *mem_object = to_qcomtee_mem_object(object);
+
+	/* Matching get is in qcomtee_memobj_param_to_object(). */
+	tee_shm_put(mem_object->shm);
+	kfree(mem_object);
+}
+
+static struct qcomtee_object_operations qcomtee_mem_object_ops = {
+	.release = qcomtee_mem_object_release,
+	.dispatch = qcomtee_mem_object_dispatch,
+};
+
+/**
+ * qcomtee_memobj_param_to_object() - OBJREF parameter to &struct qcomtee_object.
+ * @object: object returned.
+ * @param: TEE parameter.
+ * @ctx: context in which the conversion should happen.
+ *
+ * @param is an OBJREF with %QCOMTEE_OBJREF_FLAG_MEM flags.
+ *
+ * Return: On success return 0 or <0 on failure.
+ */
+int qcomtee_memobj_param_to_object(struct qcomtee_object **object,
+				   struct tee_param *param,
+				   struct tee_context *ctx)
+{
+	struct qcomtee_mem_object *mem_object __free(kfree) = NULL;
+	struct tee_shm *shm;
+	int err;
+
+	mem_object = kzalloc(sizeof(*mem_object), GFP_KERNEL);
+	if (!mem_object)
+		return -ENOMEM;
+
+	shm = tee_shm_get_from_id(ctx, param->u.objref.id);
+	if (IS_ERR(shm))
+		return PTR_ERR(shm);
+
+	/* mem-object wrapping the memref. */
+	err = qcomtee_object_user_init(&mem_object->object,
+				       QCOMTEE_OBJECT_TYPE_CB,
+				       &qcomtee_mem_object_ops, "tee-shm-%d",
+				       shm->id);
+	if (err) {
+		tee_shm_put(shm);
+
+		return err;
+	}
+
+	mem_object->paddr = shm->paddr;
+	mem_object->size = shm->size;
+	mem_object->shm = shm;
+
+	*object = &no_free_ptr(mem_object)->object;
+
+	return 0;
+}
+
+/* Reverse what qcomtee_memobj_param_to_object() does. */
+int qcomtee_memobj_param_from_object(struct tee_param *param,
+				     struct qcomtee_object *object,
+				     struct tee_context *ctx)
+{
+	struct qcomtee_mem_object *mem_object;
+
+	mem_object = to_qcomtee_mem_object(object);
+	/* Sure if the memobj is in a same context it is originated from. */
+	if (mem_object->shm->ctx != ctx)
+		return -EINVAL;
+
+	param->u.objref.id = mem_object->shm->id;
+	param->u.objref.flags = QCOMTEE_OBJREF_FLAG_MEM;
+
+	/* Passing shm->id to userspace; drop the reference. */
+	qcomtee_object_put(object);
+
+	return 0;
+}
+
+/**
+ * qcomtee_mem_object_map() - Map a memory object.
+ * @object: memory object.
+ * @map_object: created mapping object.
+ * @mem_paddr: physical address of the memory.
+ * @mem_size: size of the memory.
+ * @perms: QTEE access permissions.
+ *
+ * Return: On success return 0 or <0 on failure.
+ */
+int qcomtee_mem_object_map(struct qcomtee_object *object,
+			   struct qcomtee_object **map_object, u64 *mem_paddr,
+			   u64 *mem_size, u32 *perms)
+{
+	struct qcomtee_mem_object *mem_object = to_qcomtee_mem_object(object);
+
+	/* Reuses the memory object as a mapping object by re-sharing it. */
+	qcomtee_object_get(&mem_object->object);
+
+	*map_object = &mem_object->object;
+	*mem_paddr = mem_object->paddr;
+	*mem_size = mem_object->size;
+	*perms = QCOM_SCM_PERM_RW;
+
+	return 0;
+}

drivers/tee/qcomtee/primordial_obj.c

···
  * for native kernel services or privileged operations.
  *
  * We support:
+ *  - %QCOMTEE_OBJECT_OP_MAP_REGION to map a memory object and return mapping
+ *    object and mapping information (see qcomtee_mem_object_map()).
  *  - %QCOMTEE_OBJECT_OP_YIELD to yield by the thread running in QTEE.
  *  - %QCOMTEE_OBJECT_OP_SLEEP to wait for a period of time.
  */
 
+#define QCOMTEE_OBJECT_OP_MAP_REGION 0
 #define QCOMTEE_OBJECT_OP_YIELD 1
 #define QCOMTEE_OBJECT_OP_SLEEP 2
+
+/* Mapping information format as expected by QTEE. */
+struct qcomtee_mapping_info {
+	u64 paddr;
+	u64 len;
+	u32 perms;
+} __packed;
 
 static int
 qcomtee_primordial_obj_dispatch(struct qcomtee_object_invoke_ctx *oic,
 				struct qcomtee_object *primordial_object_unused,
 				u32 op, struct qcomtee_arg *args)
 {
+	struct qcomtee_mapping_info *map_info;
+	struct qcomtee_object *mem_object;
+	struct qcomtee_object *map_object;
 	int err = 0;
 
 	switch (op) {
···
 		cond_resched();
 		/* No output object. */
 		oic->data = NULL;
+
 		break;
 	case QCOMTEE_OBJECT_OP_SLEEP:
 		/* Check message format matched QCOMTEE_OBJECT_OP_SLEEP op. */
···
 		msleep(*(u32 *)(args[0].b.addr));
 		/* No output object. */
 		oic->data = NULL;
+
+		break;
+	case QCOMTEE_OBJECT_OP_MAP_REGION:
+		if (qcomtee_args_len(args) != 3 ||
+		    args[0].type != QCOMTEE_ARG_TYPE_OB ||
+		    args[1].type != QCOMTEE_ARG_TYPE_IO ||
+		    args[2].type != QCOMTEE_ARG_TYPE_OO ||
+		    args[0].b.size < sizeof(struct qcomtee_mapping_info))
+			return -EINVAL;
+
+		map_info = args[0].b.addr;
+		mem_object = args[1].o;
+
+		qcomtee_mem_object_map(mem_object, &map_object,
+				       &map_info->paddr, &map_info->len,
+				       &map_info->perms);
+
+		args[2].o = map_object;
+		/* One output object; pass it for cleanup to notify. */
+		oic->data = map_object;
+
+		qcomtee_object_put(mem_object);
+
 		break;
 	default:
 		err = -EINVAL;
···
 	return err;
 }
 
+/* Called after submitting the callback response. */
+static void qcomtee_primordial_obj_notify(struct qcomtee_object_invoke_ctx *oic,
+					  struct qcomtee_object *unused,
+					  int err)
+{
+	struct qcomtee_object *object = oic->data;
+
+	/* If err, QTEE did not obtain mapping object. Drop it. */
+	if (object && err)
+		qcomtee_object_put(object);
+}
+
 static struct qcomtee_object_operations qcomtee_primordial_obj_ops = {
 	.dispatch = qcomtee_primordial_obj_dispatch,
+	.notify = qcomtee_primordial_obj_notify,
 };
 
 struct qcomtee_object qcomtee_primordial_object = {

drivers/tee/qcomtee/qcomtee.h

···
 /* Flags relating to object reference. */
 #define QCOMTEE_OBJREF_FLAG_TEE		BIT(0)
 #define QCOMTEE_OBJREF_FLAG_USER	BIT(1)
+#define QCOMTEE_OBJREF_FLAG_MEM		BIT(2)
 
 /**
  * struct qcomtee - Main service struct.
···
 
 /* (2) Primordial Object. */
 extern struct qcomtee_object qcomtee_primordial_object;
+
+/* (3) Memory Object API. */
+
+/* Is it a memory object using tee_shm? */
+int is_qcomtee_memobj_object(struct qcomtee_object *object);
+
+/**
+ * qcomtee_memobj_param_to_object() - OBJREF parameter to &struct qcomtee_object.
+ * @object: object returned.
+ * @param: TEE parameter.
+ * @ctx: context in which the conversion should happen.
+ *
+ * @param is an OBJREF with %QCOMTEE_OBJREF_FLAG_MEM flags.
+ *
+ * Return: On success return 0 or <0 on failure.
+ */
+int qcomtee_memobj_param_to_object(struct qcomtee_object **object,
+				   struct tee_param *param,
+				   struct tee_context *ctx);
+
+/* Reverse what qcomtee_memobj_param_to_object() does. */
+int qcomtee_memobj_param_from_object(struct tee_param *param,
+				     struct qcomtee_object *object,
+				     struct tee_context *ctx);
+
+/**
+ * qcomtee_mem_object_map() - Map a memory object.
+ * @object: memory object.
+ * @map_object: created mapping object.
+ * @mem_paddr: physical address of the memory.
+ * @mem_size: size of the memory.
+ * @perms: QTEE access permissions.
+ *
+ * Return: On success return 0 or <0 on failure.
+ */
+int qcomtee_mem_object_map(struct qcomtee_object *object,
+			   struct qcomtee_object **map_object, u64 *mem_paddr,
+			   u64 *mem_size, u32 *perms);
 
 #endif /* QCOMTEE_H */

drivers/tee/qcomtee/shm.c

···
 static int pool_op_alloc(struct tee_shm_pool *pool, struct tee_shm *shm,
 			 size_t size, size_t align)
 {
-	if (!(shm->flags & TEE_SHM_PRIV))
-		return -ENOMEM;
-
 	return tee_dyn_shm_alloc_helper(shm, size, align, qcomtee_shm_register);
 }