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References: <20220608110734.2928245-1-tzungbi@kernel.org> <20220608110734.2928245-13-tzungbi@kernel.org>
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From:   Guenter Roeck <groeck@google.com>
Date:   Wed, 8 Jun 2022 09:14:56 -0700
Message-ID: <CABXOdTemMhLvQ_N0fgQ=VH9JgxGxnYy1DHrZx=SFFu4dxsT4iA@mail.gmail.com>
Subject: Re: [PATCH v3 12/23] platform/chrome: cros_ec_proto: handle empty
 payload in getting info legacy
To:     Tzung-Bi Shih <tzungbi@kernel.org>
Cc:     Benson Leung <bleung@chromium.org>,
        Guenter Roeck <groeck@chromium.org>,
        "open list:CHROME HARDWARE PLATFORM SUPPORT" 
        <chrome-platform@lists.linux.dev>,
        linux-kernel <linux-kernel@vger.kernel.org>
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On Wed, Jun 8, 2022 at 4:08 AM Tzung-Bi Shih <tzungbi@kernel.org> wrote:
>
> cros_ec_get_proto_info_legacy() expects to receive
> sizeof(struct ec_response_hello) from send_command().  The payload is
> valid only if the return value is positive.
>
> Return -EPROTO if send_command() returns 0 in
> cros_ec_get_proto_info_legacy().
>
> Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>

Reviewed-by: Guenter Roeck <groeck@chromium.org>


> ---
> Changes from v2:
> - Separate Kunit test to another patch.
>
>  drivers/platform/chrome/cros_ec_proto.c | 12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/platform/chrome/cros_ec_proto.c b/drivers/platform/chrome/cros_ec_proto.c
> index 04b9704ed302..473654f50bca 100644
> --- a/drivers/platform/chrome/cros_ec_proto.c
> +++ b/drivers/platform/chrome/cros_ec_proto.c
> @@ -356,7 +356,7 @@ static int cros_ec_get_proto_info_legacy(struct cros_ec_device *ec_dev)
>         struct cros_ec_command *msg;
>         struct ec_params_hello *params;
>         struct ec_response_hello *response;
> -       int ret;
> +       int ret, mapped;
>
>         ec_dev->proto_version = 2;
>
> @@ -377,12 +377,18 @@ static int cros_ec_get_proto_info_legacy(struct cros_ec_device *ec_dev)
>                 goto exit;
>         }
>
> -       ret = cros_ec_map_error(msg->result);
> -       if (ret) {
> +       mapped = cros_ec_map_error(msg->result);
> +       if (mapped) {
> +               ret = mapped;
>                 dev_err(ec_dev->dev, "EC responded to v2 hello with error: %d\n", msg->result);
>                 goto exit;
>         }
>
> +       if (ret == 0) {
> +               ret = -EPROTO;
> +               goto exit;
> +       }
> +
>         response = (struct ec_response_hello *)msg->data;
>         if (response->out_data != 0xa1b2c3d4) {
>                 dev_err(ec_dev->dev,
> --
> 2.36.1.255.ge46751e96f-goog
>