SMP: Simplified SMP interfaces

arch

@@ -1 +1 @@
-Subproject commit 211160ebe8733a5456a49b88ef4c27482690b5d6
+Subproject commit 9336bbac1c82d417d65d0a973359e4fad25e2dd1

include/nuttx/arch.h

@@ -1743,7 +1743,6 @@ int up_cpu_index(void);
  *   cpu - The index of the CPU being started.  This will be a numeric
  *         value in the range of from one to (CONFIG_SMP_NCPUS-1).  (CPU
  *         0 is already active)
- *   idletask - The entry point to the IDLE task.
  *
  * Returned Value:
  *   Zero on success; a negated errno value on failure.
@@ -1751,7 +1750,7 @@ int up_cpu_index(void);
  ****************************************************************************/
 
 #ifdef CONFIG_SMP
-int up_cpu_start(int cpu, main_t idletask);
+int up_cpu_start(int cpu);
 #endif
 
 /****************************************************************************

sched/init/init.h

@@ -65,7 +65,7 @@
 void os_start(void);
 
 /****************************************************************************
- * Name: os_smpstart
+ * Name: os_smp_start
  *
  * Description:
  *   In an SMP configution, only one CPU is initially active (CPU 0). System
@@ -82,11 +82,11 @@ void os_start(void);
  ****************************************************************************/
 
 #ifdef CONFIG_SMP
-int os_smpstart(void);
+int os_smp_start(void);
 #endif
 
 /****************************************************************************
- * Name: os_idletask
+ * Name: os_idle_trampoline
  *
  * Description:
  *   This is the common IDLE task for CPUs 1 through (CONFIG_SMP_NCPUS-1).
@@ -101,7 +101,26 @@ int os_smpstart(void);
  ****************************************************************************/
 
 #ifdef CONFIG_SMP
-int os_idletask(int argc, FAR char *argv[]);
+void os_idle_trampoline(void);
+#endif
+
+/****************************************************************************
+ * Name: os_idle_task
+ *
+ * Description:
+ *   This is the common IDLE task for CPUs 1 through (CONFIG_SMP_NCPUS-1).
+ *   It is equivalent to the CPU 0 IDLE logic in os_start.c
+ *
+ * Input Parameters:
+ *   Standard task arguments.
+ *
+ * Returned Value:
+ *   This function does not return.
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_SMP
+int os_idle_task(int argc, FAR char *argv[]);
 #endif
 
 /****************************************************************************

sched/init/os_smpstart.c

@@ -42,7 +42,6 @@
 #include <sys/types.h>
 #include <stdio.h>
 #include <queue.h>
-#include <errno.h>
 #include <debug.h>
 
 #include <nuttx/arch.h>
@@ -74,11 +73,11 @@ static const char g_idlename[] = "CPUn Idle"
 #endif
 
 /****************************************************************************
- * Private Functions
+ * Public Functions
  ****************************************************************************/
 
 /****************************************************************************
- * Name: os_idletask
+ * Name: os_idle_trampoline
  *
  * Description:
  *   This is the common IDLE task for CPUs 1 through (CONFIG_SMP_NCPUS-1).
@@ -92,7 +91,33 @@ static const char g_idlename[] = "CPUn Idle"
  *
  ****************************************************************************/
 
-int os_idletask(int argc, FAR char *argv[])
+void os_idle_trampoline(void)
+{
+  /* Transfer control to the IDLE task */
+
+  (void)os_idle_task(0, NULL);
+
+  /* The IDLE task should never return */
+
+  PANIC();
+}
+
+/****************************************************************************
+ * Name: os_idle_task
+ *
+ * Description:
+ *   This is the common IDLE task for CPUs 1 through (CONFIG_SMP_NCPUS-1).
+ *   It is equivalent to the CPU 0 IDLE logic in os_start.c
+ *
+ * Input Parameters:
+ *   Standard task arguments.
+ *
+ * Returned Value:
+ *   This function does not return.
+ *
+ ****************************************************************************/
+
+int os_idle_task(int argc, FAR char *argv[])
 {
   /* Enter the IDLE loop */
 
@@ -133,11 +158,7 @@ int os_idletask(int argc, FAR char *argv[])
 }
 
 /****************************************************************************
- * Public Functions
+ * Name: os_smp_start
- ****************************************************************************/
-
-/****************************************************************************
- * Name: os_smpstart
  *
  * Description:
  *   In an SMP configution, only one CPU is initially active (CPU 0). System
@@ -157,18 +178,38 @@ int os_idletask(int argc, FAR char *argv[])
  *
  ****************************************************************************/
 
-int os_smpstart(void)
+int os_smp_start(void)
 {
   int ret;
   int cpu;
 
-  /* CPU0 is already running.  Start the remaining CPUs */
+  /* Create a stack for all CPU IDLE threads (except CPU0 which already has
+   * a stack).
+   */
 
   for (cpu = 1; cpu < CONFIG_SMP_NCPUS; cpu++)
     {
-      /* And start the CPU.  */
+      FAR struct tcb_s *tcb = current_task(cpu);
+      DEBUGASSERT(tcb != NULL);
 
-      ret = up_cpu_start(cpu, os_idletask);
+      ret = up_create_stack(tcb, CONFIG_SMP_IDLETHREAD_STACKSIZE,
+                            TCB_FLAG_TTYPE_KERNEL);
+      if (ret < 0)
+        {
+          sdbg("ERROR: Failed to allocate stack for CPU%d\n", cpu);
+          return ret;
+        }
+    }
+
+  /* Then start all of the other CPUs after we have completed the memory
+   * allocations.  CPU0 is already running.
+   */
+
+  for (cpu = 1; cpu < CONFIG_SMP_NCPUS; cpu++)
+    {
+      /* Start the CPU */
+
+      ret = up_cpu_start(cpu);
       if (ret < 0)
         {
           sdbg("ERROR: Failed to start CPU%d: %d\n", cpu, ret);

sched/init/os_start.c

@@ -453,11 +453,13 @@ void os_start(void)
 #ifdef CONFIG_SMP
       if (cpu > 0)
         {
-          g_idletcb[cpu].cmn.entry.main = os_idletask;
+          g_idletcb[cpu].cmn.start      = os_idle_trampoline;
+          g_idletcb[cpu].cmn.entry.main = os_idle_task;
         }
       else
 #endif
         {
+          g_idletcb[cpu].cmn.start      = (start_t)os_start;
           g_idletcb[cpu].cmn.entry.main = (main_t)os_start;
         }
 
@@ -762,7 +764,7 @@ void os_start(void)
 
   /* Then start the other CPUs */
 
-  DEBUGVERIFY(os_smpstart());
+  DEBUGVERIFY(os_smp_start());
 
 #endif /* CONFIG_SMP */