firmware: imx: warn on unexpected RX
The imx_scu_call_rpc function returns the result inside the
same "msg" struct containing the transmitted message. This is
implemented by holding a pointer to msg (which is usually on the stack)
in sc_imx_rpc and writing to it from imx_scu_rx_callback.
This means that if the have_resp parameter is incorrect or SCU sends an
unexpected response for any reason the most likely result is kernel stack
corruption.
Fix this by only setting sc_imx_rpc.msg for the duration of the
imx_scu_call_rpc call and warning in imx_scu_rx_callback if unset.
Print the unexpected response data to help debugging.
Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>
Acked-by: Anson Huang <Anson.Huang@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
diff --git a/drivers/firmware/imx/imx-scu.c b/drivers/firmware/imx/imx-scu.c
index 04a24a8..869be7a 100644
--- a/drivers/firmware/imx/imx-scu.c
+++ b/drivers/firmware/imx/imx-scu.c
@@ -107,6 +107,12 @@
struct imx_sc_rpc_msg *hdr;
u32 *data = msg;
+ if (!sc_ipc->msg) {
+ dev_warn(sc_ipc->dev, "unexpected rx idx %d 0x%08x, ignore!\n",
+ sc_chan->idx, *data);
+ return;
+ }
+
if (sc_chan->idx == 0) {
hdr = msg;
sc_ipc->rx_size = hdr->size;
@@ -165,7 +171,8 @@
mutex_lock(&sc_ipc->lock);
reinit_completion(&sc_ipc->done);
- sc_ipc->msg = msg;
+ if (have_resp)
+ sc_ipc->msg = msg;
sc_ipc->count = 0;
ret = imx_scu_ipc_write(sc_ipc, msg);
if (ret < 0) {
@@ -187,6 +194,7 @@
}
out:
+ sc_ipc->msg = NULL;
mutex_unlock(&sc_ipc->lock);
dev_dbg(sc_ipc->dev, "RPC SVC done\n");
