Revert "Xtensa SMP: Avoid a nasty situation in SMP by assuring that up_release_pending() is not re-entered."

This reverts commit 733a57b4df.

arch/xtensa/src/common/xtensa_cpupause.c

@@ -229,9 +229,6 @@ int up_cpu_pause(int cpu)
    * handler from returning until up_cpu_resume() is called; g_cpu_paused
    * is a handshake that will prefent this function from returning until
    * the CPU is actually paused.
-   *
-   * REVISIT: OR should there be logic to just skip this if the other CPU
-   * is already paused.
    */
 
   DEBUGASSERT(!spin_islocked(&g_cpu_wait[cpu]) &&
@@ -300,9 +297,6 @@ int up_cpu_resume(int cpu)
   /* Release the spinlock.  Releasing the spinlock will cause the SGI2
    * handler on 'cpu' to continue and return from interrupt to the newly
    * established thread.
-   *
-   * REVISIT: Should there be a more positive handshake to assure that the
-   * resumption is complete before returning.
    */
 
   DEBUGASSERT(spin_islocked(&g_cpu_wait[cpu]) &&

arch/xtensa/src/common/xtensa_releasepending.c

@@ -39,7 +39,6 @@
 
 #include <nuttx/config.h>
 
-#include <stdbool.h>
 #include <sched.h>
 #include <debug.h>
 
@@ -69,24 +68,9 @@
 void up_release_pending(void)
 {
   struct tcb_s *rtcb = this_task();
-#ifdef CONFIG_SMP
-  static bool busy = false;
-#endif
 
   sinfo("From TCB=%p\n", rtcb);
 
-  /* In SMP configurations, this function will be called as part of leaving
-   * the critical section.  In that case, it may be re-entered as part of
-   * the sched_addreadytorun() processing.  We have to guard against that
-   * case.
-   */
-
-#ifdef CONFIG_SMP
-  if (!busy)
-    {
-      busy = true;
-#endif
-
   /* Merge the g_pendingtasks list into the ready-to-run task list */
 
   /* sched_lock(); */
@@ -172,9 +156,4 @@ void up_release_pending(void)
           xtensa_context_restore(rtcb->xcp.regs);
         }
     }
-
-#ifdef CONFIG_SMP
-      busy = false;
-    }
-#endif
 }