Commit d1cbd9e0 authored by Vincent Guittot's avatar Vincent Guittot Committed by Sudeep Holla
Browse files

firmware: arm_scmi: Fix base agent discover response 

According to scmi specification, the response of the discover agent request
is made of:
- int32 status
- uint32 agent_id
- uint8 name[16]

but the current implementation doesn't take into account the agent_id field
and only allocates a rx buffer of SCMI_MAX_STR_SIZE length

Allocate the correct length for rx buffer and copy the name from the
correct offset in the response.

While no error were returned until v5.15, v5.16-rc1 fails with virtio_scmi
transport channel:

 | arm-scmi firmware:scmi0: SCMI Notifications - Core Enabled.
 | arm-scmi firmware:scmi0: SCMI Protocol v2.0 'Linaro:PMWG' Firmware version 0x2090000
 | scmi-virtio virtio0: tx:used len 28 is larger than in buflen 24

Link: https://lore.kernel.org/r/20211117081856.9932-1-vincent.guittot@linaro.org


Fixes: b6f20ff8 ("firmware: arm_scmi: add common infrastructure and support for base protocol")
Tested-by: default avatarCristian Marussi <cristian.marussi@arm.com>
Reviewed-by: default avatarCristian Marussi <cristian.marussi@arm.com>
Signed-off-by: default avatarVincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: default avatarSudeep Holla <sudeep.holla@arm.com>
parent 95161165

drivers/firmware/arm_scmi/base.c

+12 −3
Original line number Diff line number Diff line
@@ -34,6 +34,12 @@ struct scmi_msg_resp_base_attributes { 
	__le16 reserved;

};



struct scmi_msg_resp_base_discover_agent {

	__le32 agent_id;

	u8 name[SCMI_MAX_STR_SIZE];

};





struct scmi_msg_base_error_notify {

	__le32 event_control;

#define BASE_TP_NOTIFY_ALL	BIT(0)
@@ -225,18 +231,21 @@ static int scmi_base_discover_agent_get(const struct scmi_protocol_handle *ph, 
					int id, char *name)

{

	int ret;

	struct scmi_msg_resp_base_discover_agent *agent_info;

	struct scmi_xfer *t;



	ret = ph->xops->xfer_get_init(ph, BASE_DISCOVER_AGENT,

				      sizeof(__le32), SCMI_MAX_STR_SIZE, &t);

				      sizeof(__le32), sizeof(*agent_info), &t);

	if (ret)

		return ret;



	put_unaligned_le32(id, t->tx.buf);



	ret = ph->xops->do_xfer(ph, t);

	if (!ret)

		strlcpy(name, t->rx.buf, SCMI_MAX_STR_SIZE);

	if (!ret) {

		agent_info = t->rx.buf;

		strlcpy(name, agent_info->name, SCMI_MAX_STR_SIZE);

	}



	ph->xops->xfer_put(ph, t);