linux-kernel - Re: [PATCH v5 5/7] remoteproc: core: support of the tee interface

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Date: Tue, 28 May 2024 15:30:38 -0600
From: Mathieu Poirier <mathieu.poirier@...aro.org>
To: Arnaud Pouliquen <arnaud.pouliquen@...s.st.com>
Cc: Bjorn Andersson <andersson@...nel.org>,
	linux-remoteproc@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-stm32@...md-mailman.stormreply.com
Subject: Re: [PATCH v5 5/7] remoteproc: core: support of the tee interface

On Tue, May 21, 2024 at 10:09:59AM +0200, Arnaud Pouliquen wrote:
> 1) on start:
> - Using the TEE loader, the resource table is loaded by an external entity.
> In such case the resource table address is not find from the firmware but
> provided by the TEE remoteproc framework.
> Use the rproc_get_loaded_rsc_table instead of rproc_find_loaded_rsc_table
> - test that rproc->cached_table is not null before performing the memcpy
> 
> 2)on stop
> The use of the cached_table seems mandatory:
> - during recovery sequence to have a snapshot of the resource table
>   resources used,
> - on stop to allow  for the deinitialization of resources after the
>   the remote processor has been shutdown.
> However if the TEE interface is being used, we first need to unmap the
> table_ptr before setting it to rproc->cached_table.
> The update of rproc->table_ptr to rproc->cached_table is performed in
> tee_remoteproc.
> 
> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@...s.st.com>
> ---
>  drivers/remoteproc/remoteproc_core.c | 31 +++++++++++++++++++++-------
>  1 file changed, 23 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
> index 42bca01f3bde..3a642151c983 100644
> --- a/drivers/remoteproc/remoteproc_core.c
> +++ b/drivers/remoteproc/remoteproc_core.c
> @@ -1267,6 +1267,7 @@ EXPORT_SYMBOL(rproc_resource_cleanup);
>  static int rproc_set_rsc_table_on_start(struct rproc *rproc, const struct firmware *fw)
>  {
>  	struct resource_table *loaded_table;
> +	struct device *dev = &rproc->dev;
>  
>  	/*
>  	 * The starting device has been given the rproc->cached_table as the
> @@ -1276,12 +1277,21 @@ static int rproc_set_rsc_table_on_start(struct rproc *rproc, const struct firmwa
>  	 * this information to device memory. We also update the table_ptr so
>  	 * that any subsequent changes will be applied to the loaded version.
>  	 */
> -	loaded_table = rproc_find_loaded_rsc_table(rproc, fw);
> -	if (loaded_table) {
> -		memcpy(loaded_table, rproc->cached_table, rproc->table_sz);
> -		rproc->table_ptr = loaded_table;
> +	if (rproc->tee_interface) {
> +		loaded_table = rproc_get_loaded_rsc_table(rproc, &rproc->table_sz);
> +		if (IS_ERR(loaded_table)) {
> +			dev_err(dev, "can't get resource table\n");
> +			return PTR_ERR(loaded_table);
> +		}
> +	} else {
> +		loaded_table = rproc_find_loaded_rsc_table(rproc, fw);
>  	}
>  
> +	if (loaded_table && rproc->cached_table)
> +		memcpy(loaded_table, rproc->cached_table, rproc->table_sz);
> +

Why is this not part of the else {} above as it was the case before this patch?
And why was an extra check for ->cached_table added?

This should be a simple change, i.e introduce an if {} else {} block to take
care of the two scenarios.  Plus the comment is misplaced now. 

More comments tomorrow.

Thanks,
Mathieu

> +	rproc->table_ptr = loaded_table;
> +
>  	return 0;
>  }
>  
> @@ -1318,11 +1328,16 @@ static int rproc_reset_rsc_table_on_stop(struct rproc *rproc)
>  	kfree(rproc->clean_table);
>  
>  out:
> -	/*
> -	 * Use a copy of the resource table for the remainder of the
> -	 * shutdown process.
> +	/* If the remoteproc_tee interface is used, then we have first to unmap the resource table
> +	 * before updating the proc->table_ptr reference.
>  	 */
> -	rproc->table_ptr = rproc->cached_table;
> +	if (!rproc->tee_interface) {
> +		/*
> +		 * Use a copy of the resource table for the remainder of the
> +		 * shutdown process.
> +		 */
> +		rproc->table_ptr = rproc->cached_table;
> +	}
>  	return 0;
>  }
>  
> -- 
> 2.25.1
>