Add cpufreq sanity check

This fixes bug 1585 http://bugzilla.xensource.com/bugzilla/show_bug.cgi?id=3D1585

root cause: with incorrect BIOS info, cpufreq driver may not start. in
this case, if user use xenpm to manipulate cpufreq driver, NULL
pointer will cause xen panic. this patch add the sanity check and
warning info to fix this issue.

Signed-off-by: Yu Ke <ke.yu@intel.com>

2 files changed, 16 insertions, 0 deletions

diff --git a/xen/drivers/cpufreq/cpufreq.c b/xen/drivers/cpufreq/cpufreq.c
index 7ef193a987..5524bc92a6 100644
--- a/xen/drivers/cpufreq/cpufreq.c
+++ b/xen/drivers/cpufreq/cpufreq.c
@@ -177,6 +177,15 @@ int cpufreq_add_cpu(unsigned int cpu)
             processor_pminfo[firstcpu]->perf.domain_info.coord_type) ||
             (perf->domain_info.num_processors !=
             processor_pminfo[firstcpu]->perf.domain_info.num_processors)) {
+
+            printk(KERN_WARNING "cpufreq fail to add CPU%d:"
+                   "incorrect _PSD(%"PRIu64":%"PRIu64"), "
+                   "expect(%"PRIu64"/%"PRIu64")\n",
+                   cpu, perf->domain_info.coord_type,
+                   perf->domain_info.num_processors,
+                   processor_pminfo[firstcpu]->perf.domain_info.coord_type,
+                   processor_pminfo[firstcpu]->perf.domain_info.num_processors
+                );
             return -EINVAL;
         }
     }
@@ -193,6 +202,7 @@ int cpufreq_add_cpu(unsigned int cpu)
         ret = cpufreq_driver->init(policy);
         if (ret) {
             xfree(policy);
+            cpufreq_cpu_policy[cpu] = NULL;
             return ret;
         }
         printk(KERN_EMERG"CPU %u initialization completed\n", cpu);
diff --git a/xen/drivers/cpufreq/cpufreq_ondemand.c b/xen/drivers/cpufreq/cpufreq_ondemand.c
index c30e8346db..e85bcdf45d 100644
--- a/xen/drivers/cpufreq/cpufreq_ondemand.c
+++ b/xen/drivers/cpufreq/cpufreq_ondemand.c
@@ -286,6 +286,12 @@ int cpufreq_governor_dbs(struct cpufreq_policy *policy, unsigned int event)
         break;
 
     case CPUFREQ_GOV_LIMITS:
+        if ( this_dbs_info->cur_policy == NULL )
+        {
+            printk(KERN_WARNING "CPU%d ondemand governor not started yet,"
+                    "unable to GOV_LIMIT\n", cpu);
+            return -EINVAL;
+        }
         if (policy->max < this_dbs_info->cur_policy->cur)
             __cpufreq_driver_target(this_dbs_info->cur_policy,
                 policy->max, CPUFREQ_RELATION_H);