Interrupts must be disabled in all low level context switches

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@89 42af7a65-404d-4744-a932-0658087f49c3

7 files changed, 58 insertions, 17 deletions

diff --git a/nuttx/arch/c5471/src/up_exit.c b/nuttx/arch/c5471/src/up_exit.c
index 606ea097b..c6f544776 100644
--- a/nuttx/arch/c5471/src/up_exit.c
+++ b/nuttx/arch/c5471/src/up_exit.c
@@ -76,26 +76,27 @@
 static void _up_dumponexit(FAR _TCB *tcb, FAR void *arg)
 {
   int i;
-  dbg("  TCB=%p name=%s\n", tcb, tcb->name);
+
+  lldbg("  TCB=%p name=%s\n", tcb, tcb->argv[0]);
   if (tcb->filelist)
     {
-      dbg("    filelist refcount=%d\n",
-          tcb->filelist->fl_crefs);
+      lldbg("    filelist refcount=%d\n",
+            tcb->filelist->fl_crefs);
 
       for (i = 0; i < CONFIG_NFILE_DESCRIPTORS; i++)
         {
           struct inode *inode = tcb->filelist->fl_files[i].f_inode;
           if (inode)
             {
-              dbg("      fd=%d refcount=%d\n",
-                  i, inode->i_crefs);
+              lldbg("      fd=%d refcount=%d\n",
+                    i, inode->i_crefs);
             }
         }
     }
 
   if (tcb->streams)
     {
-      dbg("    streamlist refcount=%d\n",
+      lldbg("    streamlist refcount=%d\n",
           tcb->streams->sl_crefs);
 
       for (i = 0; i < CONFIG_NFILE_STREAMS; i++)
@@ -103,9 +104,9 @@ static void _up_dumponexit(FAR _TCB *tcb, FAR void *arg)
           struct file_struct *filep = &tcb->streams->sl_streams[i];
           if (filep->fs_filedes >= 0)
             {
-              dbg("      fd=%d nbytes=%d\n",
-                  filep->fs_filedes,
-                  filep->fs_bufpos - filep->fs_bufstart);
+              lldbg("      fd=%d nbytes=%d\n",
+                    filep->fs_filedes,
+                    filep->fs_bufpos - filep->fs_bufstart);
             }
         }
     }
@@ -128,11 +129,12 @@ static void _up_dumponexit(FAR _TCB *tcb, FAR void *arg)
 void _exit(int status)
 {
   _TCB* tcb = (_TCB*)g_readytorun.head;
+  irqstate_t flags = irqsave();
 
-  dbg("TCB=%p exitting\n", tcb);
+  lldbg("TCB=%p exitting\n", tcb);
 
 #if defined(CONFIG_DUMP_ON_EXIT) && defined(CONFIG_DEBUG)
-  dbg("Other tasks:\n");
+  lldbg("Other tasks:\n");
   sched_foreach(_up_dumponexit, NULL);
 #endif
 
@@ -162,7 +164,7 @@ void _exit(int status)
    */
 
   tcb = (_TCB*)g_readytorun.head;
-  dbg("New Active Task TCB=%p\n", tcb);
+  lldbg("New Active Task TCB=%p\n", tcb);
 
   /* Then switch contexts */
 
diff --git a/nuttx/arch/dm320/src/up_exit.c b/nuttx/arch/dm320/src/up_exit.c
index 606ea097b..b96d5f824 100644
--- a/nuttx/arch/dm320/src/up_exit.c
+++ b/nuttx/arch/dm320/src/up_exit.c
@@ -76,7 +76,7 @@
 static void _up_dumponexit(FAR _TCB *tcb, FAR void *arg)
 {
   int i;
-  dbg("  TCB=%p name=%s\n", tcb, tcb->name);
+  dbg("  TCB=%p name=%s\n", tcb, tcb->argv[0]);
   if (tcb->filelist)
     {
       dbg("    filelist refcount=%d\n",
@@ -128,8 +128,9 @@ static void _up_dumponexit(FAR _TCB *tcb, FAR void *arg)
 void _exit(int status)
 {
   _TCB* tcb = (_TCB*)g_readytorun.head;
+  irqstate_t flags = irqsave();
 
-  dbg("TCB=%p exitting\n", tcb);
+  lldbg("TCB=%p exitting\n", tcb);
 
 #if defined(CONFIG_DUMP_ON_EXIT) && defined(CONFIG_DEBUG)
   dbg("Other tasks:\n");
@@ -162,7 +163,7 @@ void _exit(int status)
    */
 
   tcb = (_TCB*)g_readytorun.head;
-  dbg("New Active Task TCB=%p\n", tcb);
+  lldbg("New Active Task TCB=%p\n", tcb);
 
   /* Then switch contexts */
 
diff --git a/nuttx/arch/pjrc-8051/src/up_exit.c b/nuttx/arch/pjrc-8051/src/up_exit.c
index 5a98496a6..a9b641bab 100644
--- a/nuttx/arch/pjrc-8051/src/up_exit.c
+++ b/nuttx/arch/pjrc-8051/src/up_exit.c
@@ -41,6 +41,7 @@
 #include <sys/types.h>
 #include <sched.h>
 #include <debug.h>
+#include <8052.h>
 #include <nuttx/arch.h>
 #include "os_internal.h"
 #include "up_internal.h"
@@ -76,6 +77,12 @@ void _exit(int status)
 
   dbg("TCB=%p exitting\n", tcb);
 
+  /* Disable interrupts.  Interrupts will remain disabled until
+   * the new task is resumed below when the save IE is restored.
+   */
+
+  EA = 0;
+
   /* Remove the tcb task from the ready-to-run list.  We can
    * ignore the return value because we know that a context
    * switch is needed.
diff --git a/nuttx/include/nuttx/arch.h b/nuttx/include/nuttx/arch.h
index a243a3f6a..163f30eda 100644
--- a/nuttx/include/nuttx/arch.h
+++ b/nuttx/include/nuttx/arch.h
@@ -200,6 +200,10 @@ EXTERN void up_release_stack(FAR _TCB *dtcb);
  *   but has been prepped to execute.  Move the TCB to the
  *   ready-to-run list, restore its context, and start execution.
  *
+ *   This function is called only from the NuttX scheduling
+ *   logic.  Interrupts will always be disabled when this
+ *   function is called.
+ *
  * Inputs:
  *   tcb: Refers to the tcb to be unblocked.  This tcb is
  *     in one of the waiting tasks lists.  It must be moved to
@@ -218,6 +222,10 @@ EXTERN void up_unblock_task(FAR _TCB *tcb);
  *   the ready to run list must be stopped.  Save its context
  *   and move it to the inactive list specified by task_state.
  *
+ *   This function is called only from the NuttX scheduling
+ *   logic.  Interrupts will always be disabled when this
+ *   function is called.
+ *
  * Inputs:
  *   tcb: Refers to a task in the ready-to-run list (normally
  *     the task at the the head of the list).  It most be
@@ -241,6 +249,10 @@ EXTERN void up_block_task(FAR _TCB *tcb, tstate_t task_state);
  *   context switch if a new task is placed at the head of
  *   the ready to run list.
  *
+ *   This function is called only from the NuttX scheduling
+ *   logic.  Interrupts will always be disabled when this
+ *   function is called.
+ *
  ************************************************************/
 
 EXTERN void up_release_pending(void);
@@ -259,6 +271,10 @@ EXTERN void up_release_pending(void);
  *      the priority of the current, running task and it now has the
  *      priority.
  *
+ *   This function is called only from the NuttX scheduling
+ *   logic.  Interrupts will always be disabled when this
+ *   function is called.
+ *
  * Inputs:
  *   tcb: The TCB of the task that has been reprioritized
  *   priority: The new task priority
@@ -274,6 +290,11 @@ EXTERN void up_reprioritize_rtr(FAR _TCB *tcb, ubyte priority);
  *   This function causes the currently executing task to cease
  *   to exist.  This is a special case of task_delete().
  *
+ *   Unlike other UP APIs, this function may be called
+ *   directly from user programs in various states.  The
+ *   implementation of this function should diable interrupts
+ *   before performing scheduling operations.
+ *
  ************************************************************/
 /* Prototype is in unistd.h */
 
diff --git a/nuttx/sched/sched_setparam.c b/nuttx/sched/sched_setparam.c
index c9a935a4d..52389ae49 100644
--- a/nuttx/sched/sched_setparam.c
+++ b/nuttx/sched/sched_setparam.c
@@ -175,7 +175,9 @@ int sched_setparam(pid_t pid, const struct sched_param *param)
            {
              /* A context switch will occur. */
 
+             irqstate_t flags = irqsave();
              up_reprioritize_rtr(tcb, (ubyte)sched_priority);
+             irqrestore(flags);
            }
 
          /* Otherwise, we can just change priority since it has no effect */
@@ -202,7 +204,9 @@ int sched_setparam(pid_t pid, const struct sched_param *param)
            {
              /* A context switch will occur. */
 
+             irqstate_t flags = irqsave();
              up_reprioritize_rtr(tcb, (ubyte)sched_priority);
+             irqrestore(flags);
            }
 
          /* Otherwise, we can just change priority and re-schedule (since it
diff --git a/nuttx/sched/sched_unlock.c b/nuttx/sched/sched_unlock.c
index 773b3dd71..073f5e31f 100644
--- a/nuttx/sched/sched_unlock.c
+++ b/nuttx/sched/sched_unlock.c
@@ -93,6 +93,10 @@ STATUS sched_unlock(void)
 
   if (rtcb && !up_interrupt_context())
     {
+      /* Prevent context switches throughout the following */
+
+      irqstate_t flags = irqsave();
+
       /* Decrement the preemption lock counter */
 
       if (rtcb->lockcount)
@@ -117,6 +121,7 @@ STATUS sched_unlock(void)
              up_release_pending();
            }
         }
+      irqrestore(flags);
     }
   return OK;
 }
diff --git a/nuttx/sched/task_activate.c b/nuttx/sched/task_activate.c
index ce574428a..b216cc316 100644
--- a/nuttx/sched/task_activate.c
+++ b/nuttx/sched/task_activate.c
@@ -90,9 +90,10 @@
 
 STATUS task_activate(FAR _TCB *tcb)
 {
-#ifdef CONFIG_SCHED_INSTRUMENTATION
   irqstate_t flags = irqsave();
 
+#ifdef CONFIG_SCHED_INSTRUMENTATION
+
   /* Check if this is really a re-start */
 
   if (tcb->task_state != TSTATE_TASK_INACTIVE)
@@ -109,9 +110,9 @@ STATUS task_activate(FAR _TCB *tcb)
    */
 
   sched_note_start(tcb);
-  irqrestore(flags);
 #endif
 
   up_unblock_task(tcb);
+  irqrestore(flags);
   return OK;
 }