Re: [PATCH v2 05/12] tee: replace tee_shm_alloc()

From: Sumit Garg
Date: Thu Jan 20 2022 - 05:41:44 EST

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On Fri, 14 Jan 2022 at 20:38, Jens Wiklander <jens.wiklander@xxxxxxxxxx> wrote:
>
> tee_shm_alloc() is replaced by three new functions,
>
> tee_shm_alloc_user_buf() - for user mode allocations, replacing passing
> the flags TEE_SHM_MAPPED | TEE_SHM_DMA_BUF
>
> tee_shm_alloc_kernel_buf() - for kernel mode allocations, slightly
> optimized compared to using the flags TEE_SHM_MAPPED | TEE_SHM_DMA_BUF.
>
> tee_shm_alloc_priv_kernel_buf() - primarily for TEE driver internal use.
>

This name seems ambiguous to me and I would rather prefer it named as
tee_shm_alloc_priv_buf().

I noticed that you have done flags refactoring as part of patch #12.
So rest looks fine to me.

-Sumit

> This also makes the interface easier to use as we can get rid of the
> somewhat hard to use flags parameter.
>
> The TEE subsystem and the TEE drivers are updated to use the new
> functions instead.
>
> Signed-off-by: Jens Wiklander <jens.wiklander@xxxxxxxxxx>
> ---
> drivers/tee/optee/call.c | 2 +-
> drivers/tee/optee/device.c | 5 +-
> drivers/tee/optee/ffa_abi.c | 4 +-
> drivers/tee/optee/smc_abi.c | 5 +-
> drivers/tee/tee_shm.c | 109 +++++++++++++++++++++++-------------
> include/linux/tee_drv.h | 17 +-----
> 6 files changed, 78 insertions(+), 64 deletions(-)
>
> diff --git a/drivers/tee/optee/call.c b/drivers/tee/optee/call.c
> index b25cc1fac945..fd6ad7d6fbee 100644
> --- a/drivers/tee/optee/call.c
> +++ b/drivers/tee/optee/call.c
> @@ -120,7 +120,7 @@ struct tee_shm *optee_get_msg_arg(struct tee_context *ctx, size_t num_params,
> if (optee->rpc_arg_count)
> sz += OPTEE_MSG_GET_ARG_SIZE(optee->rpc_arg_count);
>
> - shm = tee_shm_alloc(ctx, sz, TEE_SHM_MAPPED | TEE_SHM_PRIV);
> + shm = tee_shm_alloc_priv_kernel_buf(ctx, sz);
> if (IS_ERR(shm))
> return shm;
>
> diff --git a/drivers/tee/optee/device.c b/drivers/tee/optee/device.c
> index 128a2d2a50a1..f3947be13e2e 100644
> --- a/drivers/tee/optee/device.c
> +++ b/drivers/tee/optee/device.c
> @@ -121,10 +121,9 @@ static int __optee_enumerate_devices(u32 func)
> if (rc < 0 || !shm_size)
> goto out_sess;
>
> - device_shm = tee_shm_alloc(ctx, shm_size,
> - TEE_SHM_MAPPED | TEE_SHM_DMA_BUF);
> + device_shm = tee_shm_alloc_kernel_buf(ctx, shm_size);
> if (IS_ERR(device_shm)) {
> - pr_err("tee_shm_alloc failed\n");
> + pr_err("tee_shm_alloc_kernel_buf failed\n");
> rc = PTR_ERR(device_shm);
> goto out_sess;
> }
> diff --git a/drivers/tee/optee/ffa_abi.c b/drivers/tee/optee/ffa_abi.c
> index e690d9420966..18963f7e4d48 100644
> --- a/drivers/tee/optee/ffa_abi.c
> +++ b/drivers/tee/optee/ffa_abi.c
> @@ -439,8 +439,8 @@ static void handle_ffa_rpc_func_cmd_shm_alloc(struct tee_context *ctx,
> shm = optee_rpc_cmd_alloc_suppl(ctx, arg->params[0].u.value.b);
> break;
> case OPTEE_RPC_SHM_TYPE_KERNEL:
> - shm = tee_shm_alloc(ctx, arg->params[0].u.value.b,
> - TEE_SHM_MAPPED | TEE_SHM_PRIV);
> + shm = tee_shm_alloc_priv_kernel_buf(ctx,
> + arg->params[0].u.value.b);
> break;
> default:
> arg->ret = TEEC_ERROR_BAD_PARAMETERS;
> diff --git a/drivers/tee/optee/smc_abi.c b/drivers/tee/optee/smc_abi.c
> index b679037ea794..196cd4316d7d 100644
> --- a/drivers/tee/optee/smc_abi.c
> +++ b/drivers/tee/optee/smc_abi.c
> @@ -650,7 +650,7 @@ static void handle_rpc_func_cmd_shm_alloc(struct tee_context *ctx,
> shm = optee_rpc_cmd_alloc_suppl(ctx, sz);
> break;
> case OPTEE_RPC_SHM_TYPE_KERNEL:
> - shm = tee_shm_alloc(ctx, sz, TEE_SHM_MAPPED | TEE_SHM_PRIV);
> + shm = tee_shm_alloc_priv_kernel_buf(ctx, sz);
> break;
> default:
> arg->ret = TEEC_ERROR_BAD_PARAMETERS;
> @@ -775,8 +775,7 @@ static void optee_handle_rpc(struct tee_context *ctx,
>
> switch (OPTEE_SMC_RETURN_GET_RPC_FUNC(param->a0)) {
> case OPTEE_SMC_RPC_FUNC_ALLOC:
> - shm = tee_shm_alloc(ctx, param->a1,
> - TEE_SHM_MAPPED | TEE_SHM_PRIV);
> + shm = tee_shm_alloc_priv_kernel_buf(ctx, param->a1);
> if (!IS_ERR(shm) && !tee_shm_get_pa(shm, 0, &pa)) {
> reg_pair_from_64(&param->a1, &param->a2, pa);
> reg_pair_from_64(&param->a4, &param->a5,
> diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c
> index 2c8ce0c6801a..d51bf97ce7e5 100644
> --- a/drivers/tee/tee_shm.c
> +++ b/drivers/tee/tee_shm.c
> @@ -49,25 +49,14 @@ static void tee_shm_release(struct tee_device *teedev, struct tee_shm *shm)
> tee_device_put(teedev);
> }
>
> -struct tee_shm *tee_shm_alloc(struct tee_context *ctx, size_t size, u32 flags)
> +static struct tee_shm *shm_alloc_helper(struct tee_context *ctx, size_t size,
> + size_t align, u32 flags, int id)
> {
> struct tee_device *teedev = ctx->teedev;
> struct tee_shm *shm;
> - size_t align;
> void *ret;
> int rc;
>
> - if (!(flags & TEE_SHM_MAPPED)) {
> - dev_err(teedev->dev.parent,
> - "only mapped allocations supported\n");
> - return ERR_PTR(-EINVAL);
> - }
> -
> - if ((flags & ~(TEE_SHM_MAPPED | TEE_SHM_DMA_BUF | TEE_SHM_PRIV))) {
> - dev_err(teedev->dev.parent, "invalid shm flags 0x%x", flags);
> - return ERR_PTR(-EINVAL);
> - }
> -
> if (!tee_device_get(teedev))
> return ERR_PTR(-EINVAL);
>
> @@ -84,18 +73,16 @@ struct tee_shm *tee_shm_alloc(struct tee_context *ctx, size_t size, u32 flags)
> }
>
> refcount_set(&shm->refcount, 1);
> - shm->flags = flags | TEE_SHM_POOL;
> + shm->flags = flags;
> + shm->id = id;
> +
> + /*
> + * We're assigning this as it is needed if the shm is to be
> + * registered. If this function returns OK then the caller expected
> + * to call teedev_ctx_get() or clear shm->ctx in case it's not
> + * needed any longer.
> + */
> shm->ctx = ctx;
> - if (flags & TEE_SHM_DMA_BUF) {
> - align = PAGE_SIZE;
> - /*
> - * Request to register the shm in the pool allocator below
> - * if supported.
> - */
> - shm->flags |= TEE_SHM_REGISTER;
> - } else {
> - align = 2 * sizeof(long);
> - }
>
> rc = teedev->pool->ops->alloc(teedev->pool, shm, size, align);
> if (rc) {
> @@ -103,28 +90,14 @@ struct tee_shm *tee_shm_alloc(struct tee_context *ctx, size_t size, u32 flags)
> goto err_kfree;
> }
>
> - if (flags & TEE_SHM_DMA_BUF) {
> - mutex_lock(&teedev->mutex);
> - shm->id = idr_alloc(&teedev->idr, shm, 1, 0, GFP_KERNEL);
> - mutex_unlock(&teedev->mutex);
> - if (shm->id < 0) {
> - ret = ERR_PTR(shm->id);
> - goto err_pool_free;
> - }
> - }
> -
> teedev_ctx_get(ctx);
> -
> return shm;
> -err_pool_free:
> - teedev->pool->ops->free(teedev->pool, shm);
> err_kfree:
> kfree(shm);
> err_dev_put:
> tee_device_put(teedev);
> return ret;
> }
> -EXPORT_SYMBOL_GPL(tee_shm_alloc);
>
> /**
> * tee_shm_alloc_user_buf() - Allocate shared memory for user space
> @@ -140,7 +113,36 @@ EXPORT_SYMBOL_GPL(tee_shm_alloc);
> */
> struct tee_shm *tee_shm_alloc_user_buf(struct tee_context *ctx, size_t size)
> {
> - return tee_shm_alloc(ctx, size, TEE_SHM_MAPPED | TEE_SHM_DMA_BUF);
> + u32 flags = TEE_SHM_MAPPED | TEE_SHM_DMA_BUF | TEE_SHM_REGISTER |
> + TEE_SHM_POOL;
> + struct tee_device *teedev = ctx->teedev;
> + struct tee_shm *shm;
> + void *ret;
> + int id;
> +
> + mutex_lock(&teedev->mutex);
> + id = idr_alloc(&teedev->idr, NULL, 1, 0, GFP_KERNEL);
> + mutex_unlock(&teedev->mutex);
> + if (id < 0)
> + return ERR_PTR(id);
> +
> + shm = shm_alloc_helper(ctx, size, PAGE_SIZE, flags, id);
> + if (IS_ERR(shm)) {
> + mutex_lock(&teedev->mutex);
> + idr_remove(&teedev->idr, id);
> + mutex_unlock(&teedev->mutex);
> + return shm;
> + }
> +
> + mutex_lock(&teedev->mutex);
> + ret = idr_replace(&teedev->idr, shm, id);
> + mutex_unlock(&teedev->mutex);
> + if (IS_ERR(ret)) {
> + tee_shm_free(shm);
> + return ret;
> + }
> +
> + return shm;
> }
> EXPORT_SYMBOL_GPL(tee_shm_alloc_user_buf);
>
> @@ -158,10 +160,37 @@ EXPORT_SYMBOL_GPL(tee_shm_alloc_user_buf);
> */
> struct tee_shm *tee_shm_alloc_kernel_buf(struct tee_context *ctx, size_t size)
> {
> - return tee_shm_alloc(ctx, size, TEE_SHM_MAPPED);
> + u32 flags = TEE_SHM_MAPPED | TEE_SHM_REGISTER | TEE_SHM_POOL;
> +
> + return shm_alloc_helper(ctx, size, PAGE_SIZE, flags, -1);
> }
> EXPORT_SYMBOL_GPL(tee_shm_alloc_kernel_buf);
>
> +/**
> + * tee_shm_alloc_priv_kernel_buf() - Allocate shared memory for a privatly
> + * shared kernel buffer
> + * @ctx: Context that allocates the shared memory
> + * @size: Requested size of shared memory
> + *
> + * This function returns similar shared memory as
> + * tee_shm_alloc_kernel_buf(), but with the difference that the memory
> + * might not be registered in secure world in case the driver supports
> + * passing memory not registered in advance.
> + *
> + * This function should normally only be used internally in the TEE
> + * drivers.
> + *
> + * @returns a pointer to 'struct tee_shm'
> + */
> +struct tee_shm *tee_shm_alloc_priv_kernel_buf(struct tee_context *ctx,
> + size_t size)
> +{
> + u32 flags = TEE_SHM_MAPPED | TEE_SHM_PRIV | TEE_SHM_POOL;
> +
> + return shm_alloc_helper(ctx, size, sizeof(long) * 2, flags, -1);
> +}
> +EXPORT_SYMBOL_GPL(tee_shm_alloc_priv_kernel_buf);
> +
> struct tee_shm *tee_shm_register(struct tee_context *ctx, unsigned long addr,
> size_t length, u32 flags)
> {
> diff --git a/include/linux/tee_drv.h b/include/linux/tee_drv.h
> index 808aa23308c2..e71cb0411e9c 100644
> --- a/include/linux/tee_drv.h
> +++ b/include/linux/tee_drv.h
> @@ -273,22 +273,9 @@ static inline void tee_shm_pool_free(struct tee_shm_pool *pool)
> */
> void *tee_get_drvdata(struct tee_device *teedev);
>
> -/**
> - * tee_shm_alloc() - Allocate shared memory
> - * @ctx: Context that allocates the shared memory
> - * @size: Requested size of shared memory
> - * @flags: Flags setting properties for the requested shared memory.
> - *
> - * Memory allocated as global shared memory is automatically freed when the
> - * TEE file pointer is closed. The @flags field uses the bits defined by
> - * TEE_SHM_* above. TEE_SHM_MAPPED must currently always be set. If
> - * TEE_SHM_DMA_BUF global shared memory will be allocated and associated
> - * with a dma-buf handle, else driver private memory.
> - *
> - * @returns a pointer to 'struct tee_shm'
> - */
> -struct tee_shm *tee_shm_alloc(struct tee_context *ctx, size_t size, u32 flags);
> struct tee_shm *tee_shm_alloc_user_buf(struct tee_context *ctx, size_t size);
> +struct tee_shm *tee_shm_alloc_priv_kernel_buf(struct tee_context *ctx,
> + size_t size);
> struct tee_shm *tee_shm_alloc_kernel_buf(struct tee_context *ctx, size_t size);
>
> /**
> --
> 2.31.1
>

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