Merge from trunk.

[bertos.git] / bertos / kern / proc.c

diff --git a/bertos/kern/proc.c b/bertos/kern/proc.c
index c422e729c6912963f51bfcd89f75a7cee269e290..acaf4220a1bdd3527f274762096b648f65ecac20 100644 (file)
--- a/bertos/kern/proc.c
+++ b/bertos/kern/proc.c
@@ -139,8 +139,6 @@ void proc_init(void)
        monitor_init();
        monitor_add(current_process, "main");
 #endif
-       proc_schedInit();
-
        MOD_INIT(proc);
 }
 
@@ -422,11 +420,40 @@ void proc_exit(void)
        ASSERT(0);
 }
 
-
 /**
- * Get the pointer to the user data of the current process
+ * Call the scheduler and eventually replace the current running process.
  */
-iptr_t proc_currentUserData(void)
+void proc_schedule(void)
 {
-       return current_process->user_data;
+       Process *old_process = current_process;
+
+       IRQ_ASSERT_DISABLED();
+
+       /* Poll on the ready queue for the first ready process */
+       LIST_ASSERT_VALID(&proc_ready_list);
+       while (!(current_process = (struct Process *)list_remHead(&proc_ready_list)))
+       {
+               /*
+                * Make sure we physically reenable interrupts here, no matter what
+                * the current task status is. This is important because if we
+                * are idle-spinning, we must allow interrupts, otherwise no
+                * process will ever wake up.
+                *
+                * During idle-spinning, an interrupt can occur and it may
+                * modify \p proc_ready_list. To ensure that compiler reload this
+                * variable every while cycle we call CPU_MEMORY_BARRIER.
+                * The memory barrier ensure that all variables used in this context
+                * are reloaded.
+                * \todo If there was a way to write sig_wait() so that it does not
+                * disable interrupts while waiting, there would not be any
+                * reason to do this.
+                */
+               IRQ_ENABLE;
+               CPU_IDLE;
+               MEMORY_BARRIER;
+               IRQ_DISABLE;
+       }
+       proc_switchTo(current_process, old_process);
+       /* This RET resumes the execution on the new process */
+       LOG_INFO("resuming %p:%s\n", current_process, proc_currentName());
 }