firmware: arm_scmi: Skip opp duplicates

Buggy firmware can reply with duplicated PERF opps descriptors.

Ensure that the bad duplicates reported by the platform firmware doesn't
get added to the opp-tables.

Reported-by: Johan Hovold <johan+linaro@kernel.org>
Closes: https://lore.kernel.org/lkml/ZoQjAWse2YxwyRJv@hovoldconsulting.com/
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Tested-by: Johan Hovold <johan+linaro@kernel.org>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Cc: stable@vger.kernel.org
Message-ID: <20241030125512.2884761-3-quic_sibis@quicinc.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

diff --git a/drivers/firmware/arm_scmi/perf.c b/drivers/firmware/arm_scmi/perf.c
index 2d77b5f40ca710642849ed2e22a02df5c97e68e6..32f9a9acd3e9238447f59b15e179afc2661225b7 100644 (file)
--- a/drivers/firmware/arm_scmi/perf.c
+++ b/drivers/firmware/arm_scmi/perf.c
@@ -373,7 +373,7 @@ static int iter_perf_levels_update_state(struct scmi_iterator_state *st,
        return 0;
 }
 
-static inline void
+static inline int
 process_response_opp(struct device *dev, struct perf_dom_info *dom,
                     struct scmi_opp *opp, unsigned int loop_idx,
                     const struct scmi_msg_resp_perf_describe_levels *r)
@@ -386,12 +386,16 @@ process_response_opp(struct device *dev, struct perf_dom_info *dom,
                le16_to_cpu(r->opp[loop_idx].transition_latency_us);
 
        ret = xa_insert(&dom->opps_by_lvl, opp->perf, opp, GFP_KERNEL);
-       if (ret)
+       if (ret) {
                dev_warn(dev, "Failed to add opps_by_lvl at %d for %s - ret:%d\n",
                         opp->perf, dom->info.name, ret);
+               return ret;
+       }
+
+       return 0;
 }
 
-static inline void
+static inline int
 process_response_opp_v4(struct device *dev, struct perf_dom_info *dom,
                        struct scmi_opp *opp, unsigned int loop_idx,
                        const struct scmi_msg_resp_perf_describe_levels_v4 *r)
@@ -404,9 +408,11 @@ process_response_opp_v4(struct device *dev, struct perf_dom_info *dom,
                le16_to_cpu(r->opp[loop_idx].transition_latency_us);
 
        ret = xa_insert(&dom->opps_by_lvl, opp->perf, opp, GFP_KERNEL);
-       if (ret)
+       if (ret) {
                dev_warn(dev, "Failed to add opps_by_lvl at %d for %s - ret:%d\n",
                         opp->perf, dom->info.name, ret);
+               return ret;
+       }
 
        /* Note that PERF v4 reports always five 32-bit words */
        opp->indicative_freq = le32_to_cpu(r->opp[loop_idx].indicative_freq);
@@ -415,13 +421,21 @@ process_response_opp_v4(struct device *dev, struct perf_dom_info *dom,
 
                ret = xa_insert(&dom->opps_by_idx, opp->level_index, opp,
                                GFP_KERNEL);
-               if (ret)
+               if (ret) {
                        dev_warn(dev,
                                 "Failed to add opps_by_idx at %d for %s - ret:%d\n",
                                 opp->level_index, dom->info.name, ret);
 
+                       /* Cleanup by_lvl too */
+                       xa_erase(&dom->opps_by_lvl, opp->perf);
+
+                       return ret;
+               }
+
                hash_add(dom->opps_by_freq, &opp->hash, opp->indicative_freq);
        }
+
+       return 0;
 }
 
 static int
@@ -429,16 +443,22 @@ iter_perf_levels_process_response(const struct scmi_protocol_handle *ph,
                                  const void *response,
                                  struct scmi_iterator_state *st, void *priv)
 {
+       int ret;
        struct scmi_opp *opp;
        struct scmi_perf_ipriv *p = priv;
 
-       opp = &p->perf_dom->opp[st->desc_index + st->loop_idx];
+       opp = &p->perf_dom->opp[p->perf_dom->opp_count];
        if (PROTOCOL_REV_MAJOR(p->version) <= 0x3)
-               process_response_opp(ph->dev, p->perf_dom, opp, st->loop_idx,
-                                    response);
+               ret = process_response_opp(ph->dev, p->perf_dom, opp,
+                                          st->loop_idx, response);
        else
-               process_response_opp_v4(ph->dev, p->perf_dom, opp, st->loop_idx,
-                                       response);
+               ret = process_response_opp_v4(ph->dev, p->perf_dom, opp,
+                                             st->loop_idx, response);
+
+       /* Skip BAD duplicates received from firmware */
+       if (ret)
+               return ret == -EBUSY ? 0 : ret;
+
        p->perf_dom->opp_count++;
 
        dev_dbg(ph->dev, "Level %d Power %d Latency %dus Ifreq %d Index %d\n",