firmware: arm_scmi: Harden perf domain info access

Harden internal accesses to domain info in the SCMI perf protocol.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20230717161246.1761777-2-cristian.marussi@arm.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

diff --git a/drivers/firmware/arm_scmi/perf.c b/drivers/firmware/arm_scmi/perf.c
index ecf5c4de851b764331f5372346c26495251505db..43dd242ecc49c0b078bcc4a363b8ccee57863e9c 100644 (file)
--- a/drivers/firmware/arm_scmi/perf.c
+++ b/drivers/firmware/arm_scmi/perf.c
@@ -139,7 +139,7 @@ struct perf_dom_info {
 
 struct scmi_perf_info {
        u32 version;
-       int num_domains;
+       u16 num_domains;
        enum scmi_power_scale power_scale;
        u64 stats_addr;
        u32 stats_size;
@@ -356,11 +356,26 @@ static int scmi_perf_mb_limits_set(const struct scmi_protocol_handle *ph,
        return ret;
 }
 
+static inline struct perf_dom_info *
+scmi_perf_domain_lookup(const struct scmi_protocol_handle *ph, u32 domain)
+{
+       struct scmi_perf_info *pi = ph->get_priv(ph);
+
+       if (domain >= pi->num_domains)
+               return ERR_PTR(-EINVAL);
+
+       return pi->dom_info + domain;
+}
+
 static int scmi_perf_limits_set(const struct scmi_protocol_handle *ph,
                                u32 domain, u32 max_perf, u32 min_perf)
 {
        struct scmi_perf_info *pi = ph->get_priv(ph);
-       struct perf_dom_info *dom = pi->dom_info + domain;
+       struct perf_dom_info *dom;
+
+       dom = scmi_perf_domain_lookup(ph, domain);
+       if (IS_ERR(dom))
+               return PTR_ERR(dom);
 
        if (PROTOCOL_REV_MAJOR(pi->version) >= 0x3 && !max_perf && !min_perf)
                return -EINVAL;
@@ -408,8 +423,11 @@ static int scmi_perf_mb_limits_get(const struct scmi_protocol_handle *ph,
 static int scmi_perf_limits_get(const struct scmi_protocol_handle *ph,
                                u32 domain, u32 *max_perf, u32 *min_perf)
 {
-       struct scmi_perf_info *pi = ph->get_priv(ph);
-       struct perf_dom_info *dom = pi->dom_info + domain;
+       struct perf_dom_info *dom;
+
+       dom = scmi_perf_domain_lookup(ph, domain);
+       if (IS_ERR(dom))
+               return PTR_ERR(dom);
 
        if (dom->fc_info && dom->fc_info[PERF_FC_LIMIT].get_addr) {
                struct scmi_fc_info *fci = &dom->fc_info[PERF_FC_LIMIT];
@@ -449,8 +467,11 @@ static int scmi_perf_mb_level_set(const struct scmi_protocol_handle *ph,
 static int scmi_perf_level_set(const struct scmi_protocol_handle *ph,
                               u32 domain, u32 level, bool poll)
 {
-       struct scmi_perf_info *pi = ph->get_priv(ph);
-       struct perf_dom_info *dom = pi->dom_info + domain;
+       struct perf_dom_info *dom;
+
+       dom = scmi_perf_domain_lookup(ph, domain);
+       if (IS_ERR(dom))
+               return PTR_ERR(dom);
 
        if (dom->fc_info && dom->fc_info[PERF_FC_LEVEL].set_addr) {
                struct scmi_fc_info *fci = &dom->fc_info[PERF_FC_LEVEL];
@@ -490,8 +511,11 @@ static int scmi_perf_mb_level_get(const struct scmi_protocol_handle *ph,
 static int scmi_perf_level_get(const struct scmi_protocol_handle *ph,
                               u32 domain, u32 *level, bool poll)
 {
-       struct scmi_perf_info *pi = ph->get_priv(ph);
-       struct perf_dom_info *dom = pi->dom_info + domain;
+       struct perf_dom_info *dom;
+
+       dom = scmi_perf_domain_lookup(ph, domain);
+       if (IS_ERR(dom))
+               return PTR_ERR(dom);
 
        if (dom->fc_info && dom->fc_info[PERF_FC_LEVEL].get_addr) {
                *level = ioread32(dom->fc_info[PERF_FC_LEVEL].get_addr);
@@ -574,13 +598,14 @@ static int scmi_dvfs_device_opps_add(const struct scmi_protocol_handle *ph,
        unsigned long freq;
        struct scmi_opp *opp;
        struct perf_dom_info *dom;
-       struct scmi_perf_info *pi = ph->get_priv(ph);
 
        domain = scmi_dev_domain_id(dev);
        if (domain < 0)
-               return domain;
+               return -EINVAL;
 
-       dom = pi->dom_info + domain;
+       dom = scmi_perf_domain_lookup(ph, domain);
+       if (IS_ERR(dom))
+               return PTR_ERR(dom);
 
        for (opp = dom->opp, idx = 0; idx < dom->opp_count; idx++, opp++) {
                freq = opp->perf * dom->mult_factor;
@@ -603,14 +628,17 @@ static int
 scmi_dvfs_transition_latency_get(const struct scmi_protocol_handle *ph,
                                 struct device *dev)
 {
+       int domain;
        struct perf_dom_info *dom;
-       struct scmi_perf_info *pi = ph->get_priv(ph);
-       int domain = scmi_dev_domain_id(dev);
 
+       domain = scmi_dev_domain_id(dev);
        if (domain < 0)
-               return domain;
+               return -EINVAL;
+
+       dom = scmi_perf_domain_lookup(ph, domain);
+       if (IS_ERR(dom))
+               return PTR_ERR(dom);
 
-       dom = pi->dom_info + domain;
        /* uS to nS */
        return dom->opp[dom->opp_count - 1].trans_latency_us * 1000;
 }
@@ -618,8 +646,11 @@ scmi_dvfs_transition_latency_get(const struct scmi_protocol_handle *ph,
 static int scmi_dvfs_freq_set(const struct scmi_protocol_handle *ph, u32 domain,
                              unsigned long freq, bool poll)
 {
-       struct scmi_perf_info *pi = ph->get_priv(ph);
-       struct perf_dom_info *dom = pi->dom_info + domain;
+       struct perf_dom_info *dom;
+
+       dom = scmi_perf_domain_lookup(ph, domain);
+       if (IS_ERR(dom))
+               return PTR_ERR(dom);
 
        return scmi_perf_level_set(ph, domain, freq / dom->mult_factor, poll);
 }
@@ -630,11 +661,14 @@ static int scmi_dvfs_freq_get(const struct scmi_protocol_handle *ph, u32 domain,
        int ret;
        u32 level;
        struct scmi_perf_info *pi = ph->get_priv(ph);
-       struct perf_dom_info *dom = pi->dom_info + domain;
 
        ret = scmi_perf_level_get(ph, domain, &level, poll);
-       if (!ret)
+       if (!ret) {
+               struct perf_dom_info *dom = pi->dom_info + domain;
+
+               /* Note domain is validated implicitly by scmi_perf_level_get */
                *freq = level * dom->mult_factor;
+       }
 
        return ret;
 }
@@ -643,15 +677,14 @@ static int scmi_dvfs_est_power_get(const struct scmi_protocol_handle *ph,
                                   u32 domain, unsigned long *freq,
                                   unsigned long *power)
 {
-       struct scmi_perf_info *pi = ph->get_priv(ph);
        struct perf_dom_info *dom;
        unsigned long opp_freq;
        int idx, ret = -EINVAL;
        struct scmi_opp *opp;
 
-       dom = pi->dom_info + domain;
-       if (!dom)
-               return -EIO;
+       dom = scmi_perf_domain_lookup(ph, domain);
+       if (IS_ERR(dom))
+               return PTR_ERR(dom);
 
        for (opp = dom->opp, idx = 0; idx < dom->opp_count; idx++, opp++) {
                opp_freq = opp->perf * dom->mult_factor;
@@ -670,10 +703,16 @@ static int scmi_dvfs_est_power_get(const struct scmi_protocol_handle *ph,
 static bool scmi_fast_switch_possible(const struct scmi_protocol_handle *ph,
                                      struct device *dev)
 {
+       int domain;
        struct perf_dom_info *dom;
-       struct scmi_perf_info *pi = ph->get_priv(ph);
 
-       dom = pi->dom_info + scmi_dev_domain_id(dev);
+       domain = scmi_dev_domain_id(dev);
+       if (domain < 0)
+               return false;
+
+       dom = scmi_perf_domain_lookup(ph, domain);
+       if (IS_ERR(dom))
+               return false;
 
        return dom->fc_info && dom->fc_info[PERF_FC_LEVEL].set_addr;
 }