From: Etienne Carriere <etienne.carri...@linaro.org>

Enable userspace to create a tee_shm object that refers to a dmabuf
reference.

Userspace registers the dmabuf file descriptor as in a tee_shm object.
The registration is completed with a tee_shm file descriptor returned to
userspace.

Userspace is free to close the dmabuf file descriptor now since all the
resources are now held via the tee_shm object.

Closing the tee_shm file descriptor will release all resources used by the
tee_shm object.

This change only support dmabuf references that relates to physically
contiguous memory buffers.

New tee_shm flag to identify tee_shm objects built from a registered
dmabuf, TEE_SHM_DMA_BUF.

Signed-off-by: Etienne Carriere <etienne.carri...@linaro.org>
Signed-off-by: Olivier Masse <olivier.ma...@nxp.com>
Signed-off-by: Jens Wiklander <jens.wiklan...@linaro.org>
---
 drivers/tee/tee_core.c    | 145 ++++++++++++++++++++++++++-----------
 drivers/tee/tee_private.h |   1 +
 drivers/tee/tee_shm.c     | 146 ++++++++++++++++++++++++++++++++++++--
 include/linux/tee_core.h  |   1 +
 include/linux/tee_drv.h   |  10 +++
 include/uapi/linux/tee.h  |  29 ++++++++
 6 files changed, 288 insertions(+), 44 deletions(-)

diff --git a/drivers/tee/tee_core.c b/drivers/tee/tee_core.c
index 685afcaa3ea1..3a71643766d5 100644
--- a/drivers/tee/tee_core.c
+++ b/drivers/tee/tee_core.c
@@ -353,6 +353,103 @@ tee_ioctl_shm_register(struct tee_context *ctx,
        return ret;
 }
 
+static int
+tee_ioctl_shm_register_fd(struct tee_context *ctx,
+                         struct tee_ioctl_shm_register_fd_data __user *udata)
+{
+       struct tee_ioctl_shm_register_fd_data data;
+       struct tee_shm *shm;
+       long ret;
+
+       if (copy_from_user(&data, udata, sizeof(data)))
+               return -EFAULT;
+
+       /* Currently no input flags are supported */
+       if (data.flags)
+               return -EINVAL;
+
+       shm = tee_shm_register_fd(ctx, data.fd);
+       if (IS_ERR(shm))
+               return -EINVAL;
+
+       data.id = shm->id;
+       data.flags = shm->flags;
+       data.size = shm->size;
+
+       if (copy_to_user(udata, &data, sizeof(data)))
+               ret = -EFAULT;
+       else
+               ret = tee_shm_get_fd(shm);
+
+       /*
+        * When user space closes the file descriptor the shared memory
+        * should be freed or if tee_shm_get_fd() failed then it will
+        * be freed immediately.
+        */
+       tee_shm_put(shm);
+       return ret;
+}
+
+static int param_from_user_memref(struct tee_context *ctx,
+                                 struct tee_param_memref *memref,
+                                 struct tee_ioctl_param *ip)
+{
+       struct tee_shm *shm;
+       size_t offs = 0;
+
+       /*
+        * If a NULL pointer is passed to a TA in the TEE,
+        * the ip.c IOCTL parameters is set to TEE_MEMREF_NULL
+        * indicating a NULL memory reference.
+        */
+       if (ip->c != TEE_MEMREF_NULL) {
+               /*
+                * If we fail to get a pointer to a shared
+                * memory object (and increase the ref count)
+                * from an identifier we return an error. All
+                * pointers that has been added in params have
+                * an increased ref count. It's the callers
+                * responibility to do tee_shm_put() on all
+                * resolved pointers.
+                */
+               shm = tee_shm_get_from_id(ctx, ip->c);
+               if (IS_ERR(shm))
+                       return PTR_ERR(shm);
+
+               /*
+                * Ensure offset + size does not overflow
+                * offset and does not overflow the size of
+                * the referred shared memory object.
+                */
+               if ((ip->a + ip->b) < ip->a ||
+                   (ip->a + ip->b) > shm->size) {
+                       tee_shm_put(shm);
+                       return -EINVAL;
+               }
+
+               if (shm->flags & TEE_SHM_DMA_BUF) {
+                       struct tee_shm *parent_shm;
+
+                       parent_shm = tee_shm_get_parent_shm(shm, &offs);
+                       if (parent_shm) {
+                               tee_shm_put(shm);
+                               shm = parent_shm;
+                       }
+               }
+       } else if (ctx->cap_memref_null) {
+               /* Pass NULL pointer to OP-TEE */
+               shm = NULL;
+       } else {
+               return -EINVAL;
+       }
+
+       memref->shm_offs = ip->a + offs;
+       memref->size = ip->b;
+       memref->shm = shm;
+
+       return 0;
+}
+
 static int params_from_user(struct tee_context *ctx, struct tee_param *params,
                            size_t num_params,
                            struct tee_ioctl_param __user *uparams)
@@ -360,8 +457,8 @@ static int params_from_user(struct tee_context *ctx, struct 
tee_param *params,
        size_t n;
 
        for (n = 0; n < num_params; n++) {
-               struct tee_shm *shm;
                struct tee_ioctl_param ip;
+               int rc;
 
                if (copy_from_user(&ip, uparams + n, sizeof(ip)))
                        return -EFAULT;
@@ -384,45 +481,10 @@ static int params_from_user(struct tee_context *ctx, 
struct tee_param *params,
                case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT:
                case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT:
                case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INOUT:
-                       /*
-                        * If a NULL pointer is passed to a TA in the TEE,
-                        * the ip.c IOCTL parameters is set to TEE_MEMREF_NULL
-                        * indicating a NULL memory reference.
-                        */
-                       if (ip.c != TEE_MEMREF_NULL) {
-                               /*
-                                * If we fail to get a pointer to a shared
-                                * memory object (and increase the ref count)
-                                * from an identifier we return an error. All
-                                * pointers that has been added in params have
-                                * an increased ref count. It's the callers
-                                * responibility to do tee_shm_put() on all
-                                * resolved pointers.
-                                */
-                               shm = tee_shm_get_from_id(ctx, ip.c);
-                               if (IS_ERR(shm))
-                                       return PTR_ERR(shm);
-
-                               /*
-                                * Ensure offset + size does not overflow
-                                * offset and does not overflow the size of
-                                * the referred shared memory object.
-                                */
-                               if ((ip.a + ip.b) < ip.a ||
-                                   (ip.a + ip.b) > shm->size) {
-                                       tee_shm_put(shm);
-                                       return -EINVAL;
-                               }
-                       } else if (ctx->cap_memref_null) {
-                               /* Pass NULL pointer to OP-TEE */
-                               shm = NULL;
-                       } else {
-                               return -EINVAL;
-                       }
-
-                       params[n].u.memref.shm_offs = ip.a;
-                       params[n].u.memref.size = ip.b;
-                       params[n].u.memref.shm = shm;
+                       rc = param_from_user_memref(ctx, &params[n].u.memref,
+                                                   &ip);
+                       if (rc)
+                               return rc;
                        break;
                default:
                        /* Unknown attribute */
@@ -827,6 +889,8 @@ static long tee_ioctl(struct file *filp, unsigned int cmd, 
unsigned long arg)
                return tee_ioctl_shm_alloc(ctx, uarg);
        case TEE_IOC_SHM_REGISTER:
                return tee_ioctl_shm_register(ctx, uarg);
+       case TEE_IOC_SHM_REGISTER_FD:
+               return tee_ioctl_shm_register_fd(ctx, uarg);
        case TEE_IOC_OPEN_SESSION:
                return tee_ioctl_open_session(ctx, uarg);
        case TEE_IOC_INVOKE:
@@ -1288,3 +1352,4 @@ MODULE_AUTHOR("Linaro");
 MODULE_DESCRIPTION("TEE Driver");
 MODULE_VERSION("1.0");
 MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS("DMA_BUF");
diff --git a/drivers/tee/tee_private.h b/drivers/tee/tee_private.h
index 6c6ff5d5eed2..aad7f6c7e0f0 100644
--- a/drivers/tee/tee_private.h
+++ b/drivers/tee/tee_private.h
@@ -24,6 +24,7 @@ void teedev_ctx_put(struct tee_context *ctx);
 struct tee_shm *tee_shm_alloc_user_buf(struct tee_context *ctx, size_t size);
 struct tee_shm *tee_shm_register_user_buf(struct tee_context *ctx,
                                          unsigned long addr, size_t length);
+struct tee_shm *tee_shm_get_parent_shm(struct tee_shm *shm, size_t *offs);
 
 int tee_heap_update_from_dma_buf(struct tee_device *teedev,
                                 struct dma_buf *dmabuf, size_t *offset,
diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c
index daf6e5cfd59a..8b79918468b5 100644
--- a/drivers/tee/tee_shm.c
+++ b/drivers/tee/tee_shm.c
@@ -4,6 +4,7 @@
  */
 #include <linux/anon_inodes.h>
 #include <linux/device.h>
+#include <linux/dma-buf.h>
 #include <linux/idr.h>
 #include <linux/io.h>
 #include <linux/mm.h>
@@ -15,6 +16,16 @@
 #include <linux/highmem.h>
 #include "tee_private.h"
 
+/* extra references appended to shm object for registered shared memory */
+struct tee_shm_dmabuf_ref {
+       struct tee_shm shm;
+       size_t offset;
+       struct dma_buf *dmabuf;
+       struct dma_buf_attachment *attach;
+       struct sg_table *sgt;
+       struct tee_shm *parent_shm;
+};
+
 static void shm_put_kernel_pages(struct page **pages, size_t page_count)
 {
        size_t n;
@@ -45,7 +56,23 @@ static void release_registered_pages(struct tee_shm *shm)
 
 static void tee_shm_release(struct tee_device *teedev, struct tee_shm *shm)
 {
-       if (shm->flags & TEE_SHM_POOL) {
+       struct tee_shm *parent_shm = NULL;
+       void *p = shm;
+
+       if (shm->flags & TEE_SHM_DMA_BUF) {
+               struct tee_shm_dmabuf_ref *ref;
+
+               ref = container_of(shm, struct tee_shm_dmabuf_ref, shm);
+               parent_shm = ref->parent_shm;
+               p = ref;
+               if (ref->attach) {
+                       dma_buf_unmap_attachment(ref->attach, ref->sgt,
+                                                DMA_BIDIRECTIONAL);
+
+                       dma_buf_detach(ref->dmabuf, ref->attach);
+               }
+               dma_buf_put(ref->dmabuf);
+       } else if (shm->flags & TEE_SHM_POOL) {
                teedev->pool->ops->free(teedev->pool, shm);
        } else if (shm->flags & TEE_SHM_DYNAMIC) {
                int rc = teedev->desc->ops->shm_unregister(shm->ctx, shm);
@@ -57,9 +84,10 @@ static void tee_shm_release(struct tee_device *teedev, 
struct tee_shm *shm)
                release_registered_pages(shm);
        }
 
-       teedev_ctx_put(shm->ctx);
+       if (shm->ctx)
+               teedev_ctx_put(shm->ctx);
 
-       kfree(shm);
+       kfree(p);
 
        tee_device_put(teedev);
 }
@@ -169,7 +197,7 @@ struct tee_shm *tee_shm_alloc_user_buf(struct tee_context 
*ctx, size_t size)
  * tee_client_invoke_func(). The memory allocated is later freed with a
  * call to tee_shm_free().
  *
- * @returns a pointer to 'struct tee_shm'
+ * @returns a pointer to 'struct tee_shm' on success, and ERR_PTR on failure
  */
 struct tee_shm *tee_shm_alloc_kernel_buf(struct tee_context *ctx, size_t size)
 {
@@ -179,6 +207,116 @@ struct tee_shm *tee_shm_alloc_kernel_buf(struct 
tee_context *ctx, size_t size)
 }
 EXPORT_SYMBOL_GPL(tee_shm_alloc_kernel_buf);
 
+struct tee_shm *tee_shm_register_fd(struct tee_context *ctx, int fd)
+{
+       struct tee_shm_dmabuf_ref *ref;
+       int rc;
+
+       if (!tee_device_get(ctx->teedev))
+               return ERR_PTR(-EINVAL);
+
+       teedev_ctx_get(ctx);
+
+       ref = kzalloc(sizeof(*ref), GFP_KERNEL);
+       if (!ref) {
+               rc = -ENOMEM;
+               goto err_put_tee;
+       }
+
+       refcount_set(&ref->shm.refcount, 1);
+       ref->shm.ctx = ctx;
+       ref->shm.id = -1;
+       ref->shm.flags = TEE_SHM_DMA_BUF;
+
+       ref->dmabuf = dma_buf_get(fd);
+       if (IS_ERR(ref->dmabuf)) {
+               rc = PTR_ERR(ref->dmabuf);
+               goto err_kfree_ref;
+       }
+
+       rc = tee_heap_update_from_dma_buf(ctx->teedev, ref->dmabuf,
+                                         &ref->offset, &ref->shm,
+                                         &ref->parent_shm);
+       if (!rc)
+               goto out;
+       if (rc != -EINVAL)
+               goto err_put_dmabuf;
+
+       ref->attach = dma_buf_attach(ref->dmabuf, &ctx->teedev->dev);
+       if (IS_ERR(ref->attach)) {
+               rc = PTR_ERR(ref->attach);
+               goto err_put_dmabuf;
+       }
+
+       ref->sgt = dma_buf_map_attachment(ref->attach, DMA_BIDIRECTIONAL);
+       if (IS_ERR(ref->sgt)) {
+               rc = PTR_ERR(ref->sgt);
+               goto err_detach;
+       }
+
+       if (sg_nents(ref->sgt->sgl) != 1) {
+               rc = PTR_ERR(ref->sgt->sgl);
+               goto err_unmap_attachement;
+       }
+
+       ref->shm.paddr = page_to_phys(sg_page(ref->sgt->sgl));
+       ref->shm.size = ref->sgt->sgl->length;
+
+out:
+       mutex_lock(&ref->shm.ctx->teedev->mutex);
+       ref->shm.id = idr_alloc(&ref->shm.ctx->teedev->idr, &ref->shm,
+                               1, 0, GFP_KERNEL);
+       mutex_unlock(&ref->shm.ctx->teedev->mutex);
+       if (ref->shm.id < 0) {
+               rc = ref->shm.id;
+               if (ref->attach)
+                       goto err_unmap_attachement;
+               goto err_put_dmabuf;
+       }
+
+       return &ref->shm;
+
+err_unmap_attachement:
+       dma_buf_unmap_attachment(ref->attach, ref->sgt, DMA_BIDIRECTIONAL);
+err_detach:
+       dma_buf_detach(ref->dmabuf, ref->attach);
+err_put_dmabuf:
+       dma_buf_put(ref->dmabuf);
+err_kfree_ref:
+       kfree(ref);
+err_put_tee:
+       teedev_ctx_put(ctx);
+       tee_device_put(ctx->teedev);
+
+       return ERR_PTR(rc);
+}
+EXPORT_SYMBOL_GPL(tee_shm_register_fd);
+
+struct tee_shm *tee_shm_get_parent_shm(struct tee_shm *shm, size_t *offs)
+{
+       struct tee_shm *parent_shm = NULL;
+
+       if (shm->flags & TEE_SHM_DMA_BUF) {
+               struct tee_shm_dmabuf_ref *ref;
+
+               ref = container_of(shm, struct tee_shm_dmabuf_ref, shm);
+               if (ref->parent_shm) {
+                       /*
+                        * the shm already has one reference to
+                        * ref->parent_shm so we should be clear of 0.
+                        * We're getting another reference since the caller
+                        * of this function expects to put the returned
+                        * parent_shm when it's done with it.
+                        */
+                       parent_shm = ref->parent_shm;
+                       refcount_inc(&parent_shm->refcount);
+                       *offs = ref->offset;
+               }
+       }
+
+       return parent_shm;
+}
+
 /**
  * tee_shm_alloc_priv_buf() - Allocate shared memory for a privately shared
  *                           kernel buffer
diff --git a/include/linux/tee_core.h b/include/linux/tee_core.h
index 16ef078247ae..6bd833b6d0e1 100644
--- a/include/linux/tee_core.h
+++ b/include/linux/tee_core.h
@@ -28,6 +28,7 @@
 #define TEE_SHM_USER_MAPPED    BIT(1)  /* Memory mapped in user space */
 #define TEE_SHM_POOL           BIT(2)  /* Memory allocated from pool */
 #define TEE_SHM_PRIV           BIT(3)  /* Memory private to TEE driver */
+#define TEE_SHM_DMA_BUF                BIT(4)  /* Memory with dma-buf handle */
 
 #define TEE_DEVICE_FLAG_REGISTERED     0x1
 #define TEE_MAX_DEV_NAME_LEN           32
diff --git a/include/linux/tee_drv.h b/include/linux/tee_drv.h
index a54c203000ed..824f1251de60 100644
--- a/include/linux/tee_drv.h
+++ b/include/linux/tee_drv.h
@@ -116,6 +116,16 @@ struct tee_shm *tee_shm_alloc_kernel_buf(struct 
tee_context *ctx, size_t size);
 struct tee_shm *tee_shm_register_kernel_buf(struct tee_context *ctx,
                                            void *addr, size_t length);
 
+/**
+ * tee_shm_register_fd() - Register shared memory from file descriptor
+ *
+ * @ctx:       Context that allocates the shared memory
+ * @fd:                Shared memory file descriptor reference
+ *
+ * @returns a pointer to 'struct tee_shm' on success, and ERR_PTR on failure
+ */
+struct tee_shm *tee_shm_register_fd(struct tee_context *ctx, int fd);
+
 /**
  * tee_shm_free() - Free shared memory
  * @shm:       Handle to shared memory to free
diff --git a/include/uapi/linux/tee.h b/include/uapi/linux/tee.h
index d0430bee8292..1f9a4ac2b211 100644
--- a/include/uapi/linux/tee.h
+++ b/include/uapi/linux/tee.h
@@ -118,6 +118,35 @@ struct tee_ioctl_shm_alloc_data {
 #define TEE_IOC_SHM_ALLOC      _IOWR(TEE_IOC_MAGIC, TEE_IOC_BASE + 1, \
                                     struct tee_ioctl_shm_alloc_data)
 
+/**
+ * struct tee_ioctl_shm_register_fd_data - Shared memory registering argument
+ * @fd:                [in] File descriptor identifying the shared memory
+ * @size:      [out] Size of shared memory to allocate
+ * @flags:     [in] Flags to/from allocation.
+ * @id:                [out] Identifier of the shared memory
+ *
+ * The flags field should currently be zero as input. Updated by the call
+ * with actual flags as defined by TEE_IOCTL_SHM_* above.
+ * This structure is used as argument for TEE_IOC_SHM_REGISTER_FD below.
+ */
+struct tee_ioctl_shm_register_fd_data {
+       __s64 fd;
+       __u64 size;
+       __u32 flags;
+       __s32 id;
+};
+
+/**
+ * TEE_IOC_SHM_REGISTER_FD - register a shared memory from a file descriptor
+ *
+ * Returns a file descriptor on success or < 0 on failure
+ *
+ * The returned file descriptor refers to the shared memory object in kernel
+ * land. The shared memory is freed when the descriptor is closed.
+ */
+#define TEE_IOC_SHM_REGISTER_FD        _IOWR(TEE_IOC_MAGIC, TEE_IOC_BASE + 8, \
+                                    struct tee_ioctl_shm_register_fd_data)
+
 /**
  * struct tee_ioctl_buf_data - Variable sized buffer
  * @buf_ptr:   [in] A __user pointer to a buffer
-- 
2.43.0

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