Re: [PATCH v1] misc: fastrpc: Fix DSP capabilities request

[Srinivas Kandagatla]

On 21/06/2023 07:28, Ekansh Gupta wrote:
> Incorrect remote arguments are getting passed when requesting for
> capabilities from DSP. Also there is no requirement to update the
> PD type as it might cause problems for any PD other than user PD.
> In addition to this, the collected capability information is not
> getting copied properly to user. Add changes to address these
> problems and get correct DSP capabilities.
>
> Fixes: 6c16fd8bdd40 ("misc: fastrpc: Add support to get DSP capabilities")
> Cc: stable <stable@xxxxxxxxxx>
> Tested-by: Ekansh Gupta <quic_ekangupt@xxxxxxxxxxx>
> Signed-off-by: Ekansh Gupta <quic_ekangupt@xxxxxxxxxxx>
> ---
>   drivers/misc/fastrpc.c | 7 +++----
>   1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
> index 30d4d04..776c596 100644
> --- a/drivers/misc/fastrpc.c
> +++ b/drivers/misc/fastrpc.c
> @@ -1693,9 +1693,8 @@ static int fastrpc_get_info_from_dsp(struct fastrpc_user *fl, uint32_t *dsp_attr
>   	args[0].length = sizeof(dsp_attr_buf_len);
>   	args[0].fd = -1;
>   	args[1].ptr = (u64)(uintptr_t)&dsp_attr_buf[1];

<--snip
> -	args[1].length = dsp_attr_buf_len;
> +	args[1].length = dsp_attr_buf_len * sizeof(uint32_t);
-->
>   	args[1].fd = -1;
> -	fl->pd = USER_PD;

this looks fine.
>   
>   	return fastrpc_internal_invoke(fl, true, FASTRPC_DSP_UTILITIES_HANDLE,
>   				       FASTRPC_SCALARS(0, 1, 1), args);
> @@ -1723,7 +1722,7 @@ static int fastrpc_get_info_from_kernel(struct fastrpc_ioctl_capability *cap,
>   	if (!dsp_attributes)
>   		return -ENOMEM;
>   

<-- snip
> -	err = fastrpc_get_info_from_dsp(fl, dsp_attributes, FASTRPC_MAX_DSP_ATTRIBUTES_LEN);
> +	err = fastrpc_get_info_from_dsp(fl, dsp_attributes, FASTRPC_MAX_DSP_ATTRIBUTES);

-->
Before this change we passed a value which is already multipled now we 
pass a value that will be mulitplied inside fastrpc_get_info_from_dsp, 
both will work, but I dont see any value in doing this change.


>   	if (err == DSP_UNSUPPORTED_API) {
>   		dev_info(&cctx->rpdev->dev,
>   			 "Warning: DSP capabilities not supported on domain: %d\n", domain);
> @@ -1776,7 +1775,7 @@ static int fastrpc_get_dsp_info(struct fastrpc_user *fl, char __user *argp)
>   	if (err)
>   		return err;
>   
> -	if (copy_to_user(argp, &cap.capability, sizeof(cap.capability)))
> +	if (copy_to_user(argp, &cap, sizeof(cap)))

Can you explain this change, and what is it fixing exactly?

--srini
>   		return -EFAULT;
>   
>   	return 0;