tee: use reference counting for tee_context
We need to ensure that tee_context is present until last shared buffer will be freed. Signed-off-by: Volodymyr Babchuk <vlad.babchuk@gmail.com> Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
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@ -54,6 +54,7 @@ static int tee_open(struct inode *inode, struct file *filp)
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goto err;
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}
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kref_init(&ctx->refcount);
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ctx->teedev = teedev;
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INIT_LIST_HEAD(&ctx->list_shm);
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filp->private_data = ctx;
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@ -68,19 +69,40 @@ err:
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return rc;
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}
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void teedev_ctx_get(struct tee_context *ctx)
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{
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if (ctx->releasing)
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return;
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kref_get(&ctx->refcount);
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}
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static void teedev_ctx_release(struct kref *ref)
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{
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struct tee_context *ctx = container_of(ref, struct tee_context,
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refcount);
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ctx->releasing = true;
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ctx->teedev->desc->ops->release(ctx);
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kfree(ctx);
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}
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void teedev_ctx_put(struct tee_context *ctx)
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{
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if (ctx->releasing)
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return;
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kref_put(&ctx->refcount, teedev_ctx_release);
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}
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static void teedev_close_context(struct tee_context *ctx)
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{
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tee_device_put(ctx->teedev);
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teedev_ctx_put(ctx);
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}
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static int tee_release(struct inode *inode, struct file *filp)
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{
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struct tee_context *ctx = filp->private_data;
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struct tee_device *teedev = ctx->teedev;
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struct tee_shm *shm;
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ctx->teedev->desc->ops->release(ctx);
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mutex_lock(&ctx->teedev->mutex);
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list_for_each_entry(shm, &ctx->list_shm, link)
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shm->ctx = NULL;
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mutex_unlock(&ctx->teedev->mutex);
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kfree(ctx);
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tee_device_put(teedev);
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teedev_close_context(filp->private_data);
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return 0;
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}
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@ -73,4 +73,7 @@ int tee_shm_get_fd(struct tee_shm *shm);
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bool tee_device_get(struct tee_device *teedev);
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void tee_device_put(struct tee_device *teedev);
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void teedev_ctx_get(struct tee_context *ctx);
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void teedev_ctx_put(struct tee_context *ctx);
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#endif /*TEE_PRIVATE_H*/
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@ -53,6 +53,9 @@ static void tee_shm_release(struct tee_shm *shm)
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kfree(shm->pages);
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}
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if (shm->ctx)
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teedev_ctx_put(shm->ctx);
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kfree(shm);
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tee_device_put(teedev);
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@ -187,6 +190,7 @@ struct tee_shm *__tee_shm_alloc(struct tee_context *ctx,
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}
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if (ctx) {
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teedev_ctx_get(ctx);
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mutex_lock(&teedev->mutex);
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list_add_tail(&shm->link, &ctx->list_shm);
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mutex_unlock(&teedev->mutex);
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@ -253,6 +257,8 @@ struct tee_shm *tee_shm_register(struct tee_context *ctx, unsigned long addr,
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return ERR_PTR(-ENOTSUPP);
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}
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teedev_ctx_get(ctx);
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shm = kzalloc(sizeof(*shm), GFP_KERNEL);
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if (!shm) {
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ret = ERR_PTR(-ENOMEM);
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@ -334,6 +340,7 @@ err:
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kfree(shm->pages);
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}
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kfree(shm);
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teedev_ctx_put(ctx);
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tee_device_put(teedev);
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return ret;
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}
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@ -17,6 +17,7 @@
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#include <linux/types.h>
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#include <linux/idr.h>
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#include <linux/kref.h>
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#include <linux/list.h>
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#include <linux/tee.h>
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@ -42,11 +43,17 @@ struct tee_shm_pool;
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* @teedev: pointer to this drivers struct tee_device
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* @list_shm: List of shared memory object owned by this context
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* @data: driver specific context data, managed by the driver
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* @refcount: reference counter for this structure
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* @releasing: flag that indicates if context is being released right now.
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* It is needed to break circular dependency on context during
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* shared memory release.
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*/
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struct tee_context {
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struct tee_device *teedev;
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struct list_head list_shm;
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void *data;
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struct kref refcount;
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bool releasing;
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};
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struct tee_param_memref {
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