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.

Signed-off-by: Amirreza Zarrabi <amirreza.zarr...@oss.qualcomm.com>
---
 drivers/tee/qcomtee/Makefile          |   1 +
 drivers/tee/qcomtee/call.c            |  10 +-
 drivers/tee/qcomtee/mem_obj.c         | 172 ++++++++++++++++++++++++++++++++++
 drivers/tee/qcomtee/primordial_obj.c  |  50 ++++++++++
 drivers/tee/qcomtee/qcomtee_private.h |  39 ++++++++
 drivers/tee/qcomtee/shm.c             |   3 -
 6 files changed, 270 insertions(+), 5 deletions(-)

diff --git a/drivers/tee/qcomtee/Makefile b/drivers/tee/qcomtee/Makefile
index a3a2d00e83f0..6cb9fd38dc67 100644
--- a/drivers/tee/qcomtee/Makefile
+++ b/drivers/tee/qcomtee/Makefile
@@ -3,6 +3,7 @@ obj-$(CONFIG_QCOMTEE) += qcomtee.o
 qcomtee-objs += async.o
 qcomtee-objs += call.o
 qcomtee-objs += core.o
+qcomtee-objs += mem_obj.o
 qcomtee-objs += primordial_obj.o
 qcomtee-objs += qcom_scm.o
 qcomtee-objs += release.o
diff --git a/drivers/tee/qcomtee/call.c b/drivers/tee/qcomtee/call.c
index 9e288723ec21..239ffc24476a 100644
--- a/drivers/tee/qcomtee/call.c
+++ b/drivers/tee/qcomtee/call.c
@@ -110,8 +110,8 @@ void qcomtee_context_del_qtee_object(struct tee_param 
*param,
  * &enum qcomtee_arg_type value. It gets the object's refcount in @arg;
  * the caller should manage to put it afterward.
  *
- * For user objects (i.e. (param->u.objref.flags & QCOMTEE_OBJREF_FLAG_USER)),
- * qcomtee_user_param_to_object() calls qcomtee_object_get() to keep a
+ * For non-QTEE objects (i.e. !(param->u.objref.flags &
+ * QCOMTEE_OBJREF_FLAG_TEE)), qcomtee_object_get() is called to keep a
  * temporary copy for the driver as the release of objects are asynchronous
  * and they may go away even before returning from the invocation.
  *
@@ -135,6 +135,9 @@ int qcomtee_objref_to_arg(struct qcomtee_arg *arg, struct 
tee_param *param,
        /* 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);
+       /* 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);
        } else {
                err = -EINVAL;
        }
@@ -181,6 +184,9 @@ int qcomtee_objref_from_arg(struct tee_param *param, struct 
qcomtee_arg *arg,
                if (is_qcomtee_user_object(object))
                        err = qcomtee_user_param_from_object(param, object,
                                                             ctx);
+               else if (is_qcomtee_memobj_object(object))
+                       err = qcomtee_memobj_param_from_object(param, object,
+                                                              ctx);
                else
                        err = -EINVAL;
 
diff --git a/drivers/tee/qcomtee/mem_obj.c b/drivers/tee/qcomtee/mem_obj.c
new file mode 100644
index 000000000000..e17eb3b3dc2e
--- /dev/null
+++ b/drivers/tee/qcomtee/mem_obj.c
@@ -0,0 +1,172 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2025 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/mm.h>
+#include <linux/firmware/qcom/qcom_scm.h>
+
+#include "qcomtee_private.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.
+ * It calls qcomtee_object_get() to keep a copy of @object for the driver
+ * as well as a copy for QTEE.
+ *
+ * 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 (!shm)
+               return -EINVAL;
+
+       /* 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;
+       qcomtee_object_get(*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;
+}
diff --git a/drivers/tee/qcomtee/primordial_obj.c 
b/drivers/tee/qcomtee/primordial_obj.c
index a30967d89c91..598557f09746 100644
--- a/drivers/tee/qcomtee/primordial_obj.c
+++ b/drivers/tee/qcomtee/primordial_obj.c
@@ -16,18 +16,31 @@
  * 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) {
@@ -35,6 +48,7 @@ qcomtee_primordial_obj_dispatch(struct 
qcomtee_object_invoke_ctx *oic,
                cond_resched();
                /* No output object. */
                oic->data = NULL;
+
                break;
        case QCOMTEE_OBJECT_OP_SLEEP:
                /* Check message format matched QCOMTEE_OBJECT_OP_SLEEP op. */
@@ -46,6 +60,29 @@ qcomtee_primordial_obj_dispatch(struct 
qcomtee_object_invoke_ctx *oic,
                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;
@@ -54,8 +91,21 @@ qcomtee_primordial_obj_dispatch(struct 
qcomtee_object_invoke_ctx *oic,
        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 = {
diff --git a/drivers/tee/qcomtee/qcomtee_private.h 
b/drivers/tee/qcomtee/qcomtee_private.h
index e59cfb3b79dd..a70052803399 100644
--- a/drivers/tee/qcomtee/qcomtee_private.h
+++ b/drivers/tee/qcomtee/qcomtee_private.h
@@ -15,6 +15,7 @@
 /* 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.
@@ -222,4 +223,42 @@ int qcomtee_user_object_submit(struct tee_context *ctx,
 /* (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_PRIVATE_H */
diff --git a/drivers/tee/qcomtee/shm.c b/drivers/tee/qcomtee/shm.c
index 998aabe96434..9bdf9e48bfeb 100644
--- a/drivers/tee/qcomtee/shm.c
+++ b/drivers/tee/qcomtee/shm.c
@@ -113,9 +113,6 @@ static int qcomtee_shm_unregister(struct tee_context *ctx, 
struct tee_shm *shm)
 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);
 }
 

-- 
2.34.1

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