P-FP: make PCP available to userspace

Prior to that it was only used internally for DPCP

2 files changed, 141 insertions, 0 deletions

diff --git a/litmus/fdso.c b/litmus/fdso.c
index 04c0b55e41d3..cd85b9cd9a0a 100644
--- a/litmus/fdso.c
+++ b/litmus/fdso.c
@@ -26,6 +26,7 @@ static const struct fdso_ops* fdso_ops[] = {
         &generic_lock_ops, /* MPCP_SEM */
         &generic_lock_ops, /* MPCP_VS_SEM */
         &generic_lock_ops, /* DPCP_SEM */
+        &generic_lock_ops, /* PCP_SEM */
 };
 
 static int fdso_create(void** obj_ref, obj_type_t type, void* __user config)
diff --git a/litmus/sched_pfp.c b/litmus/sched_pfp.c
index d5dd78d941c6..42d17b0c08fd 100644
--- a/litmus/sched_pfp.c
+++ b/litmus/sched_pfp.c
@@ -950,6 +950,8 @@ static struct litmus_lock* pfp_new_mpcp(int vspin)
 
 
 struct pcp_semaphore {
+        struct litmus_lock litmus_lock;
+
         struct list_head ceiling;
 
         /* current resource holder */
@@ -962,6 +964,12 @@ struct pcp_semaphore {
         int on_cpu;
 };
 
+static inline struct pcp_semaphore* pcp_from_lock(struct litmus_lock* lock)
+{
+        return container_of(lock, struct pcp_semaphore, litmus_lock);
+}
+
+
 struct pcp_state {
         struct list_head system_ceiling;
 
@@ -1203,6 +1211,123 @@ static void pcp_init_semaphore(struct pcp_semaphore* sem, int cpu)
         sem->on_cpu = cpu;
 }
 
+int pfp_pcp_lock(struct litmus_lock* l)
+{
+        struct task_struct* t = current;
+        struct pcp_semaphore *sem = pcp_from_lock(l);
+
+        int eprio = effective_agent_priority(get_priority(t));
+        int from  = get_partition(t);
+        int to    = sem->on_cpu;
+
+        if (!is_realtime(t) || from != to)
+                return -EPERM;
+
+        preempt_disable();
+
+        pcp_raise_ceiling(sem, eprio);
+
+        preempt_enable();
+
+        return 0;
+}
+
+int pfp_pcp_unlock(struct litmus_lock* l)
+{
+        struct task_struct *t = current;
+        struct pcp_semaphore *sem = pcp_from_lock(l);
+
+        int err = 0;
+
+        preempt_disable();
+
+        if (sem->on_cpu != smp_processor_id() || sem->owner != t) {
+                err = -EINVAL;
+                goto out;
+        }
+
+        /* give it back */
+        pcp_lower_ceiling(sem);
+
+out:
+        preempt_enable();
+
+        return err;
+}
+
+int pfp_pcp_open(struct litmus_lock* l, void* __user config)
+{
+        struct task_struct *t = current;
+        struct pcp_semaphore *sem = pcp_from_lock(l);
+
+        int cpu, eprio;
+
+        if (!is_realtime(t))
+                /* we need to know the real-time priority */
+                return -EPERM;
+
+        if (get_user(cpu, (int*) config))
+                return -EFAULT;
+
+        /* make sure the resource location matches */
+        if (cpu != sem->on_cpu)
+                return -EINVAL;
+
+        eprio = effective_agent_priority(get_priority(t));
+
+        pcp_update_prio_ceiling(sem, eprio);
+
+        return 0;
+}
+
+int pfp_pcp_close(struct litmus_lock* l)
+{
+        struct task_struct *t = current;
+        struct pcp_semaphore *sem = pcp_from_lock(l);
+
+        int owner = 0;
+
+        preempt_disable();
+
+        if (sem->on_cpu == smp_processor_id())
+                owner = sem->owner == t;
+
+        preempt_enable();
+
+        if (owner)
+                pfp_pcp_unlock(l);
+
+        return 0;
+}
+
+void pfp_pcp_free(struct litmus_lock* lock)
+{
+        kfree(pcp_from_lock(lock));
+}
+
+
+static struct litmus_lock_ops pfp_pcp_lock_ops = {
+        .close  = pfp_pcp_close,
+        .lock   = pfp_pcp_lock,
+        .open   = pfp_pcp_open,
+        .unlock = pfp_pcp_unlock,
+        .deallocate = pfp_pcp_free,
+};
+
+
+static struct litmus_lock* pfp_new_pcp(int on_cpu)
+{
+        struct pcp_semaphore* sem;
+
+        sem = kmalloc(sizeof(*sem), GFP_KERNEL);
+        if (!sem)
+                return NULL;
+
+        sem->litmus_lock.ops = &pfp_pcp_lock_ops;
+        pcp_init_semaphore(sem, on_cpu);
+
+        return &sem->litmus_lock;
+}
 
 /* ******************** DPCP support ********************** */
 
@@ -1459,6 +1584,21 @@ static long pfp_allocate_lock(struct litmus_lock **lock, int type,
                 } else
                         err = -ENOMEM;
                 break;
+
+        case PCP_SEM:
+                /* Priority Ceiling Protocol */
+                if (get_user(cpu, (int*) config))
+                        return -EFAULT;
+
+                if (!cpu_online(cpu))
+                        return -EINVAL;
+
+                *lock = pfp_new_pcp(cpu);
+                if (*lock)
+                        err = 0;
+                else
+                        err = -ENOMEM;
+                break;
         };
 
         return err;