[PATCH 4/4] firmware: arm_scmi: Validate Powercap domains before state access

[Sudeep Holla]

Powercap protocol v2 keeps local enable and last-cap state per
domain. Some public operations indexed that state before checking that
the supplied domain id was valid, and cap_enable_get() updated it even
when cap_get() failed.

Validate the domain before touching the per-domain state and only
refresh cached enable state after a successful cap_get().

Signed-off-by: Sudeep Holla <sudeep.holla at kernel.org>
---
 drivers/firmware/arm_scmi/powercap.c | 25 ++++++++++++++++++-------
 1 file changed, 18 insertions(+), 7 deletions(-)

diff --git a/drivers/firmware/arm_scmi/powercap.c b/drivers/firmware/arm_scmi/powercap.c
index ab9733f4458b..eb5c35cad026 100644
--- a/drivers/firmware/arm_scmi/powercap.c
+++ b/drivers/firmware/arm_scmi/powercap.c
@@ -453,10 +453,14 @@ static int scmi_powercap_cap_set(const struct scmi_protocol_handle *ph,
 		return -EINVAL;
 
 	/* Just log the last set request if acting on a disabled domain */
-	if (PROTOCOL_REV_MAJOR(ph->version) >= 0x2 &&
-	    !pi->states[domain_id].enabled) {
-		pi->states[domain_id].last_pcap = power_cap;
-		return 0;
+	if (PROTOCOL_REV_MAJOR(ph->version) >= 0x2) {
+		if (!scmi_powercap_dom_info_get(ph, domain_id))
+			return -EINVAL;
+
+		if (!pi->states[domain_id].enabled) {
+			pi->states[domain_id].last_pcap = power_cap;
+			return 0;
+		}
 	}
 
 	return __scmi_powercap_cap_set(ph, pi, domain_id,
@@ -637,6 +641,9 @@ static int scmi_powercap_cap_enable_set(const struct scmi_protocol_handle *ph,
 	if (PROTOCOL_REV_MAJOR(ph->version) < 0x2)
 		return -EINVAL;
 
+	if (!scmi_powercap_dom_info_get(ph, domain_id))
+		return -EINVAL;
+
 	if (enable == pi->states[domain_id].enabled)
 		return 0;
 
@@ -678,16 +685,20 @@ static int scmi_powercap_cap_enable_get(const struct scmi_protocol_handle *ph,
 	if (PROTOCOL_REV_MAJOR(ph->version) < 0x2)
 		return 0;
 
+	if (!scmi_powercap_dom_info_get(ph, domain_id))
+		return -EINVAL;
+
 	/*
 	 * Report always real platform state; platform could have ignored
 	 * a previous disable request. Default true on any error.
 	 */
 	ret = scmi_powercap_cap_get(ph, domain_id, &power_cap);
-	if (!ret)
+	if (!ret) {
 		*enable = !!power_cap;
 
-	/* Update internal state with current real platform state */
-	pi->states[domain_id].enabled = *enable;
+		/* Update internal state with current real platform state */
+		pi->states[domain_id].enabled = *enable;
+	}
 
 	return 0;
 }

-- 
2.43.0