Re: [PATCH] remoteproc: core: Remove casting to rproc_handle_resource_t

[Sami Tolvanen]

Hi,

On Sun, Feb 21, 2021 at 11:18 PM Jindong Yue <jindong.yue@xxxxxxx> wrote:
>
> There are four different callback functions that are used for the
> rproc_handle_resource_t callback that all have different second
> parameter types.
>
> rproc_handle_vdev -> struct fw_rsc_vdev
> rproc_handle_trace -> struct fw_rsc_trace
> rproc_handle_devmem -> struct fw_rsc_devmem
> rproc_handle_carveout -> struct fw_rsc_carveout
>
> These callbacks are cast to rproc_handle_resource_t so that there is no
> error about incompatible pointer types. Unfortunately, this is a control
> flow integrity violation, which verifies that the callback function's
> types match the prototypes exactly before jumping.

Thank you for sending the patch! It might be worth noting that Clang's
Control-Flow Integrity checking is currently used only in Android
kernels, so while the type mismatches are real and should be fixed,
they don't result in runtime errors without this feature.

> To fix this, change the second parameter of all functions to void * and
> use a local variable with the correct type so that everything works
> properly. With this, we can remove casting to rproc_handle_resource_t
> for these functions.
>
> Signed-off-by: Jindong Yue <jindong.yue@xxxxxxx>
> Reviewed-by: Peng Fan <peng.fan@xxxxxxx>

This looks correct to me. Please feel free to add:

Reviewed-by: Sami Tolvanen <samitolvanen@xxxxxxxxxx>

Sami