Re: [PATCH v9 4/7] remoteproc: core: Add TEE interface support for firmware release

Arnaud POULIQUEN
2024-09-17T17:03:32Z

Hello Mathieu,

On 9/12/24 17:26, Mathieu Poirier wrote:
> On Fri, Aug 30, 2024 at 11:51:44AM +0200, Arnaud Pouliquen wrote:
>> Add support for releasing remote processor firmware through
>> the Trusted Execution Environment (TEE) interface.
>>
>> The tee_rproc_release_fw() function is called in the following cases:
>>
>> - An error occurs in rproc_start() between the loading of the segments and
>> the start of the remote processor.
>> - When rproc_release_fw is called on error or after stopping the remote
>> processor.
>>
>> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
>> ---
>> drivers/remoteproc/remoteproc_core.c | 10 ++++++++--
>> 1 file changed, 8 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
>> index 7694817f25d4..32052dedc149 100644
>> --- a/drivers/remoteproc/remoteproc_core.c
>> +++ b/drivers/remoteproc/remoteproc_core.c
>> @@ -29,6 +29,7 @@
>> #include <linux/debugfs.h>
>> #include <linux/rculist.h>
>> #include <linux/remoteproc.h>
>> +#include <linux/remoteproc_tee.h>
>> #include <linux/iommu.h>
>> #include <linux/idr.h>
>> #include <linux/elf.h>
>> @@ -1258,6 +1259,9 @@ static int rproc_alloc_registered_carveouts(struct rproc *rproc)
>>
>> static void rproc_release_fw(struct rproc *rproc)
>> {
>> + if (rproc->state == RPROC_OFFLINE && rproc->tee_interface)
>> + tee_rproc_release_fw(rproc);
>
> Function tee_rproc_release_fw() returns a value that is ignored. I don't know
> how it passes the Sparse checker but I already see patches coming in my Inbox to
> deal with that. In this case there is nothing else to do if there is an error
> releasing the firware. As such I would put a (void) in front and add a comment
> about the return value being ignore on purpose.

Instead of ignoring the error, I wonder if we should panic in
tee_rproc_release_fw(). Indeed, we would be in an unexpected state without any
possible action to return to a normal state.

Regards,
Arnaud

>
>> +
>> /* Free the copy of the resource table */
>> kfree(rproc->cached_table);
>> rproc->cached_table = NULL;
>> @@ -1348,7 +1352,7 @@ static int rproc_start(struct rproc *rproc, const struct firmware *fw)
>> if (ret) {
>> dev_err(dev, "failed to prepare subdevices for %s: %d\n",
>> rproc->name, ret);
>> - goto reset_table_ptr;
>> + goto release_fw;
>> }
>>
>> /* power up the remote processor */
>> @@ -1376,7 +1380,9 @@ static int rproc_start(struct rproc *rproc, const struct firmware *fw)
>> rproc->ops->stop(rproc);
>> unprepare_subdevices:
>> rproc_unprepare_subdevices(rproc);
>> -reset_table_ptr:
>> +release_fw:
>> + if (rproc->tee_interface)
>> + tee_rproc_release_fw(rproc);
>
> Same here.
>
>> rproc->table_ptr = rproc->cached_table;
>>
>> return ret;
>> --
>> 2.25.1
>>