More PIC32 context switching logic

git-svn-id: https://nuttx.svn.sourceforge.net/svnroot/nuttx/trunk@3625 7fd9a85b-ad96-42d3-883c-3090e2eb8679

11 files changed, 838 insertions, 8 deletions

diff --git a/nuttx/arch/mips/include/mips32/irq.h b/nuttx/arch/mips/include/mips32/irq.h
index 9db3ae26af..7b869a3b91 100755
--- a/nuttx/arch/mips/include/mips32/irq.h
+++ b/nuttx/arch/mips/include/mips32/irq.h
@@ -316,6 +316,13 @@ struct xcptcontext
 
 #ifndef CONFIG_DISABLE_SIGNALS
   void *sigdeliver; /* Actual type is sig_deliver_t */
+
+  /* These additional register save locations are used to implement the
+   * signal delivery trampoline.
+   */
+
+  uint32_t saved_epc;    /* Trampoline PC */
+  uint32_t saved_status; /* Status with interrupts disabled. */
 #endif
 
   /* Register save area */
diff --git a/nuttx/arch/mips/src/mips32/up_assert.c b/nuttx/arch/mips/src/mips32/up_assert.c
index c10a994711..977fe82874 100644
--- a/nuttx/arch/mips/src/mips32/up_assert.c
+++ b/nuttx/arch/mips/src/mips32/up_assert.c
@@ -1,5 +1,5 @@
 /****************************************************************************
- * arch/mips/src/arm/up_assert.c
+ * arch/mips/src/mips32/up_assert.c
  *
  *   Copyright (C) 2011 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
diff --git a/nuttx/arch/mips/src/mips32/up_dumpstate.c b/nuttx/arch/mips/src/mips32/up_dumpstate.c
index 0b1c893b8c..061bce448f 100644
--- a/nuttx/arch/mips/src/mips32/up_dumpstate.c
+++ b/nuttx/arch/mips/src/mips32/up_dumpstate.c
@@ -1,5 +1,5 @@
 /****************************************************************************
- * arch/mips/src/arm/up_dumpstate.c
+ * arch/mips/src/mips32/up_dumpstate.c
  *
  *   Copyright (C) 2011 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
diff --git a/nuttx/arch/mips/src/mips32/up_initialstate.c b/nuttx/arch/mips/src/mips32/up_initialstate.c
index 8236aaff74..89db4d7b90 100644
--- a/nuttx/arch/mips/src/mips32/up_initialstate.c
+++ b/nuttx/arch/mips/src/mips32/up_initialstate.c
@@ -1,7 +1,7 @@
 /****************************************************************************
- * arch/arm/src/cortexm3/up_initialstate.c
+ * arch/mips/src/mips32/up_initialstate.c
  *
- *   Copyright (C) 2009 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2011 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
  *
  * Redistribution and use in source and binary forms, with or without
diff --git a/nuttx/arch/mips/src/mips32/up_releasepending.c b/nuttx/arch/mips/src/mips32/up_releasepending.c
new file mode 100755
index 0000000000..ea36d152a9
--- /dev/null
+++ b/nuttx/arch/mips/src/mips32/up_releasepending.c
@@ -0,0 +1,130 @@
+/****************************************************************************
+ *  arch/mips/src/mips32/up_releasepending.c
+ *
+ *   Copyright (C) 2011 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <sched.h>
+#include <debug.h>
+#include <nuttx/arch.h>
+
+#include "os_internal.h"
+#include "up_internal.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: up_release_pending
+ *
+ * Description:
+ *   Release and ready-to-run tasks that have
+ *   collected in the pending task list.  This can call a
+ *   context switch if a new task is placed at the head of
+ *   the ready to run list.
+ *
+ ****************************************************************************/
+
+void up_release_pending(void)
+{
+  _TCB *rtcb = (_TCB*)g_readytorun.head;
+
+  slldbg("From TCB=%p\n", rtcb);
+
+  /* Merge the g_pendingtasks list into the g_readytorun task list */
+
+  /* sched_lock(); */
+  if (sched_mergepending())
+    {
+      /* The currently active task has changed!  We will need to
+       * switch contexts.  First check if we are operating in
+       * interrupt context:
+       */
+
+      if (current_regs)
+        {
+          /* Yes, then we have to do things differently.
+           * Just copy the current_regs into the OLD rtcb.
+           */
+
+           up_savestate(rtcb->xcp.regs);
+
+          /* Restore the exception context of the rtcb at the (new) head 
+           * of the g_readytorun task list.
+           */
+
+          rtcb = (_TCB*)g_readytorun.head;
+          slldbg("New Active Task TCB=%p\n", rtcb);
+
+          /* Then switch contexts */
+
+          up_restorestate(rtcb->xcp.regs);
+        }
+
+      /* No, then we will need to perform the user context switch */
+
+      else
+        {
+          /* Switch context to the context of the task at the head of the
+           * ready to run list.
+           */
+
+          _TCB *nexttcb = (_TCB*)g_readytorun.head;
+          up_switchcontext(rtcb->xcp.regs, nexttcb->xcp.regs);
+
+          /* up_switchcontext forces a context switch to the task at the
+           * head of the ready-to-run list.  It does not 'return' in the
+           * normal sense.  When it does return, it is because the blocked
+           * task is again ready to run and has execution priority.
+           */
+        }
+    }
+}
diff --git a/nuttx/arch/mips/src/mips32/up_reprioritizertr.c b/nuttx/arch/mips/src/mips32/up_reprioritizertr.c
new file mode 100755
index 0000000000..19a4f05c6f
--- /dev/null
+++ b/nuttx/arch/mips/src/mips32/up_reprioritizertr.c
@@ -0,0 +1,182 @@
+/****************************************************************************
+ *  arch/mips/src/mips32/up_reprioritizertr.c
+ *
+ *   Copyright (C) 2010 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <sched.h>
+#include <debug.h>
+
+#include <nuttx/arch.h>
+
+#include "os_internal.h"
+#include "up_internal.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: up_reprioritize_rtr
+ *
+ * Description:
+ *   Called when the priority of a running or
+ *   ready-to-run task changes and the reprioritization will 
+ *   cause a context switch.  Two cases:
+ *
+ *   1) The priority of the currently running task drops and the next
+ *      task in the ready to run list has priority.
+ *   2) An idle, ready to run task's priority has been raised above the
+ *      the priority of the current, running task and it now has the
+ *      priority.
+ *
+ * Inputs:
+ *   tcb: The TCB of the task that has been reprioritized
+ *   priority: The new task priority
+ *
+ ****************************************************************************/
+
+void up_reprioritize_rtr(_TCB *tcb, uint8_t priority)
+{
+  /* Verify that the caller is sane */
+
+  if (tcb->task_state < FIRST_READY_TO_RUN_STATE ||
+      tcb->task_state > LAST_READY_TO_RUN_STATE ||
+      priority < SCHED_PRIORITY_MIN || 
+      priority > SCHED_PRIORITY_MAX)
+    {
+       PANIC(OSERR_BADREPRIORITIZESTATE);
+    }
+  else
+    {
+      _TCB *rtcb = (_TCB*)g_readytorun.head;
+      bool switch_needed;
+
+      slldbg("TCB=%p PRI=%d\n", tcb, priority);
+
+      /* Remove the tcb task from the ready-to-run list.
+       * sched_removereadytorun will return true if we just
+       * remove the head of the ready to run list.
+       */
+
+      switch_needed = sched_removereadytorun(tcb);
+
+      /* Setup up the new task priority */
+
+      tcb->sched_priority = (uint8_t)priority;
+
+      /* Return the task to the specified blocked task list.
+       * sched_addreadytorun will return true if the task was
+       * added to the new list.  We will need to perform a context
+       * switch only if the EXCLUSIVE or of the two calls is non-zero
+       * (i.e., one and only one the calls changes the head of the
+       * ready-to-run list).
+       */
+
+      switch_needed ^= sched_addreadytorun(tcb);
+
+      /* Now, perform the context switch if one is needed */
+
+      if (switch_needed)
+        {
+          /* If we are going to do a context switch, then now is the right
+           * time to add any pending tasks back into the ready-to-run list.
+           * task list now
+           */
+
+          if (g_pendingtasks.head)
+            {
+              sched_mergepending();
+            }
+
+         /* Are we in an interrupt handler? */
+
+          if (current_regs)
+            {
+              /* Yes, then we have to do things differently.
+               * Just copy the current_regs into the OLD rtcb.
+               */
+
+               up_savestate(rtcb->xcp.regs);
+
+              /* Restore the exception context of the rtcb at the (new) head 
+               * of the g_readytorun task list.
+               */
+
+              rtcb = (_TCB*)g_readytorun.head;
+              slldbg("New Active Task TCB=%p\n", rtcb);
+
+              /* Then switch contexts */
+
+              up_restorestate(rtcb->xcp.regs);
+            }
+
+          /* No, then we will need to perform the user context switch */
+
+          else
+            {
+              /* Switch context to the context of the task at the head of the
+               * ready to run list.
+               */
+
+              _TCB *nexttcb = (_TCB*)g_readytorun.head;
+              up_switchcontext(rtcb->xcp.regs, nexttcb->xcp.regs);
+
+              /* up_switchcontext forces a context switch to the task at the
+               * head of the ready-to-run list.  It does not 'return' in the
+               * normal sense.  When it does return, it is because the blocked
+               * task is again ready to run and has execution priority.
+               */
+            }
+        }
+    }
+}
diff --git a/nuttx/arch/mips/src/mips32/up_schedulesigaction.c b/nuttx/arch/mips/src/mips32/up_schedulesigaction.c
new file mode 100644
index 0000000000..7f4f0a0c98
--- /dev/null
+++ b/nuttx/arch/mips/src/mips32/up_schedulesigaction.c
@@ -0,0 +1,212 @@
+/****************************************************************************
+ * arch/mips/src/mips32/up_schedulesigaction.c
+ *
+ *   Copyright (C) 2011 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <stdint.h>
+#include <sched.h>
+#include <debug.h>
+
+#include <nuttx/arch.h>
+#include <arch/mips32/cp0.h>
+
+#include "os_internal.h"
+#include "up_internal.h"
+#include "up_arch.h"
+
+#ifndef CONFIG_DISABLE_SIGNALS
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: up_schedule_sigaction
+ *
+ * Description:
+ *   This function is called by the OS when one or more
+ *   signal handling actions have been queued for execution.
+ *   The architecture specific code must configure things so
+ *   that the 'igdeliver' callback is executed on the thread
+ *   specified by 'tcb' as soon as possible.
+ *
+ *   This function may be called from interrupt handling logic.
+ *
+ *   This operation should not cause the task to be unblocked
+ *   nor should it cause any immediate execution of sigdeliver.
+ *   Typically, a few cases need to be considered:
+ *
+ *   (1) This function may be called from an interrupt handler
+ *       During interrupt processing, all xcptcontext structures
+ *       should be valid for all tasks.  That structure should
+ *       be modified to invoke sigdeliver() either on return
+ *       from (this) interrupt or on some subsequent context
+ *       switch to the recipient task.
+ *   (2) If not in an interrupt handler and the tcb is NOT
+ *       the currently executing task, then again just modify
+ *       the saved xcptcontext structure for the recipient
+ *       task so it will invoke sigdeliver when that task is
+ *       later resumed.
+ *   (3) If not in an interrupt handler and the tcb IS the
+ *       currently executing task -- just call the signal
+ *       handler now.
+ *
+ ****************************************************************************/
+
+void up_schedule_sigaction(_TCB *tcb, sig_deliver_t sigdeliver)
+{
+  uint32_t status;
+
+  /* Refuse to handle nested signal actions */
+
+  sdbg("tcb=0x%p sigdeliver=0x%p\n", tcb, sigdeliver);
+
+  if (!tcb->xcp.sigdeliver)
+    {
+      irqstate_t flags;
+
+      /* Make sure that interrupts are disabled */
+
+      flags = irqsave();
+
+      /* First, handle some special cases when the signal is
+       * being delivered to the currently executing task.
+       */
+
+      sdbg("rtcb=0x%p current_regs=0x%p\n", g_readytorun.head, current_regs);
+
+      if (tcb == (_TCB*)g_readytorun.head)
+        {
+          /* CASE 1:  We are not in an interrupt handler and
+           * a task is signalling itself for some reason.
+           */
+
+          if (!current_regs)
+            {
+              /* In this case just deliver the signal now. */
+
+              sigdeliver(tcb);
+            }
+
+          /* CASE 2:  We are in an interrupt handler AND the
+           * interrupted task is the same as the one that
+           * must receive the signal, then we will have to modify
+           * the return state as well as the state in the TCB.
+           *
+           * Hmmm... there looks like a latent bug here: The following
+           * logic would fail in the strange case where we are in an
+           * interrupt handler, the thread is signalling itself, but
+           * a context switch to another task has occurred so that
+           * current_regs does not refer to the thread at g_readytorun.head!
+           */
+
+          else
+            {
+              /* Save the return lr and cpsr and one scratch register
+               * These will be restored by the signal trampoline after
+               * the signals have been delivered.
+               */
+
+              tcb->xcp.sigdeliver       = sigdeliver;
+              tcb->xcp.saved_epc        = current_regs[REG_EPC];
+              tcb->xcp.saved_status     = current_regs[REG_STATUS];
+
+              /* Then set up to vector to the trampoline with interrupts
+               * disabled
+               */
+
+              current_regs[REG_EPC]      = (uint32_t)up_sigdeliver;
+              status                     = current_regs[REG_STATUS];
+              status                    &= ~CP0_STATUS_IM_MASK;
+              status                    |= CP0_STATUS_IM_SWINTS;
+              current_regs[REG_STATUS]   = status;
+
+              /* And make sure that the saved context in the TCB
+               * is the same as the interrupt return context.
+               */
+
+              up_savestate(tcb->xcp.regs);
+            }
+        }
+
+      /* Otherwise, we are (1) signaling a task is not running
+       * from an interrupt handler or (2) we are not in an
+       * interrupt handler and the running task is signalling
+       * some non-running task.
+       */
+
+      else
+        {
+          /* Save the return lr and cpsr and one scratch register
+           * These will be restored by the signal trampoline after
+           * the signals have been delivered.
+           */
+
+          tcb->xcp.sigdeliver       = sigdeliver;
+          tcb->xcp.saved_epc        = tcb->xcp.regs[REG_EPC];
+          tcb->xcp.saved_status     = tcb->xcp.regs[REG_STATUS];
+
+          /* Then set up to vector to the trampoline with interrupts
+           * disabled
+           */
+
+          tcb->xcp.regs[REG_EPC]     = (uint32_t)up_sigdeliver;
+          status                     = current_regs[REG_STATUS];
+          status                    &= ~CP0_STATUS_IM_MASK;
+          status                    |= CP0_STATUS_IM_SWINTS;
+          tcb->xcp.regs[REG_STATUS]  = status;
+        }
+
+      irqrestore(flags);
+    }
+}
+
+#endif /* !CONFIG_DISABLE_SIGNALS */
diff --git a/nuttx/arch/mips/src/mips32/up_sigdeliver.c b/nuttx/arch/mips/src/mips32/up_sigdeliver.c
new file mode 100644
index 0000000000..05a9560701
--- /dev/null
+++ b/nuttx/arch/mips/src/mips32/up_sigdeliver.c
@@ -0,0 +1,141 @@
+/****************************************************************************
+ * arch/mips/src/mips32/up_sigdeliver.c
+ *
+ *   Copyright (C) 2011 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <stdint.h>
+#include <sched.h>
+#include <debug.h>
+
+#include <nuttx/irq.h>
+#include <nuttx/arch.h>
+#include <arch/board/board.h>
+
+#include "os_internal.h"
+#include "up_internal.h"
+#include "up_arch.h"
+
+#ifndef CONFIG_DISABLE_SIGNALS
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: up_sigdeliver
+ *
+ * Description:
+ *   This is the a signal handling trampoline.  When a signal action was
+ *   posted.  The task context was mucked with and forced to branch to this
+ *   location with interrupts disabled.
+ *
+ ****************************************************************************/
+
+void up_sigdeliver(void)
+{
+  _TCB  *rtcb = (_TCB*)g_readytorun.head;
+  uint32_t regs[XCPTCONTEXT_REGS];
+  sig_deliver_t sigdeliver;
+
+  /* Save the errno.  This must be preserved throughout the signal handling
+   * so that the user code final gets the correct errno value (probably
+   * EINTR).
+   */
+
+  int saved_errno = rtcb->pterrno;
+
+  up_ledon(LED_SIGNAL);
+
+  sdbg("rtcb=%p sigdeliver=%p sigpendactionq.head=%p\n",
+        rtcb, rtcb->xcp.sigdeliver, rtcb->sigpendactionq.head);
+  ASSERT(rtcb->xcp.sigdeliver != NULL);
+
+  /* Save the real return state on the stack. */
+
+  up_copystate(regs, rtcb->xcp.regs);
+  regs[REG_EPC]        = rtcb->xcp.saved_epc;
+  regs[REG_STATUS]     = rtcb->xcp.saved_status;
+
+  /* Get a local copy of the sigdeliver function pointer. We do this so that
+   * we can nullify the sigdeliver function pointer in the TCB and accept
+   * more signal deliveries while processing the current pending signals.
+   */
+
+  sigdeliver           = rtcb->xcp.sigdeliver;
+  rtcb->xcp.sigdeliver = NULL;
+
+  /* Then restore the task interrupt state */
+
+  irqrestore((uint16_t)regs[REG_STATUS]);
+
+  /* Deliver the signals */
+
+  sigdeliver(rtcb);
+
+  /* Output any debug messages BEFORE restoring errno (because they may
+   * alter errno), then disable interrupts again and restore the original
+   * errno that is needed by the user logic (it is probably EINTR).
+   */
+
+  sdbg("Resuming\n");
+  (void)irqsave();
+  rtcb->pterrno = saved_errno;
+
+  /* Then restore the correct state for this thread of
+   * execution.
+   */
+
+  up_ledoff(LED_SIGNAL);
+  up_fullcontextrestore(regs);
+}
+
+#endif /* !CONFIG_DISABLE_SIGNALS */
+
diff --git a/nuttx/arch/mips/src/mips32/up_unblocktask.c b/nuttx/arch/mips/src/mips32/up_unblocktask.c
new file mode 100755
index 0000000000..c32bc573e9
--- /dev/null
+++ b/nuttx/arch/mips/src/mips32/up_unblocktask.c
@@ -0,0 +1,157 @@
+/****************************************************************************
+ *  arch/mips/src/mips32/up_unblocktask.c
+ *
+ *   Copyright (C) 2010 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <sched.h>
+#include <debug.h>
+#include <nuttx/arch.h>
+
+#include "os_internal.h"
+#include "clock_internal.h"
+#include "up_internal.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: up_unblock_task
+ *
+ * Description:
+ *   A task is currently in an inactive task list
+ *   but has been prepped to execute.  Move the TCB to the
+ *   ready-to-run list, restore its context, and start execution.
+ *
+ * Inputs:
+ *   tcb: Refers to the tcb to be unblocked.  This tcb is
+ *     in one of the waiting tasks lists.  It must be moved to
+ *     the ready-to-run list and, if it is the highest priority
+ *     ready to run taks, executed.
+ *
+ ****************************************************************************/
+
+void up_unblock_task(_TCB *tcb)
+{
+  /* Verify that the context switch can be performed */
+
+  if ((tcb->task_state < FIRST_BLOCKED_STATE) ||
+      (tcb->task_state > LAST_BLOCKED_STATE))
+    {
+      PANIC(OSERR_BADUNBLOCKSTATE);
+    }
+  else
+    {
+      _TCB *rtcb = (_TCB*)g_readytorun.head;
+
+      /* Remove the task from the blocked task list */
+
+      sched_removeblocked(tcb);
+
+      /* Reset its timeslice.  This is only meaningful for round
+       * robin tasks but it doesn't here to do it for everything
+       */
+
+#if CONFIG_RR_INTERVAL > 0
+      tcb->timeslice = CONFIG_RR_INTERVAL / MSEC_PER_TICK;
+#endif
+
+      /* Add the task in the correct location in the prioritized
+       * g_readytorun task list
+       */
+
+      if (sched_addreadytorun(tcb))
+        {
+          /* The currently active task has changed! We need to do
+           * a context switch to the new task.
+           *
+           * Are we in an interrupt handler? 
+           */
+
+          if (current_regs)
+            {
+              /* Yes, then we have to do things differently.
+               * Just copy the current_regs into the OLD rtcb.
+               */
+
+               up_savestate(rtcb->xcp.regs);
+
+              /* Restore the exception context of the rtcb at the (new) head 
+               * of the g_readytorun task list.
+               */
+
+              rtcb = (_TCB*)g_readytorun.head;
+
+              /* Then switch contexts */
+
+              up_restorestate(rtcb->xcp.regs);
+            }
+
+          /* No, then we will need to perform the user context switch */
+
+          else
+            {
+              /* Switch context to the context of the task at the head of the
+               * ready to run list.
+               */
+
+               _TCB *nexttcb = (_TCB*)g_readytorun.head;
+               up_switchcontext(rtcb->xcp.regs, nexttcb->xcp.regs);
+
+              /* up_switchcontext forces a context switch to the task at the
+               * head of the ready-to-run list.  It does not 'return' in the
+               * normal sense.  When it does return, it is because the blocked
+               * task is again ready to run and has execution priority.
+               */
+           }
+        }
+    }
+}
diff --git a/nuttx/arch/mips/src/pic32mx/Make.defs b/nuttx/arch/mips/src/pic32mx/Make.defs
index 94bd5b629d..011cd1ba9d 100755
--- a/nuttx/arch/mips/src/pic32mx/Make.defs
+++ b/nuttx/arch/mips/src/pic32mx/Make.defs
@@ -42,9 +42,10 @@ HEAD_ASRC = pic32mx-head.S
 CMN_ASRCS = 
 CMN_CSRCS = up_allocateheap.c up_assert.c up_blocktask.c up_copystate.c \
 			up_createstack.c up_doirq.c up_exit.c up_idle.c up_initialize.c \
-			up_initialstate.c up_interruptcontext.c up_irq.c \
-			up_lowputs.c up_mdelay.c up_modifyreg8.c up_modifyreg16.c \
-			up_modifyreg32.c up_puts.c up_releasestack.c up_udelay.c \
+			up_initialstate.c up_interruptcontext.c up_irq.c up_lowputs.c \
+			up_mdelay.c up_modifyreg8.c up_modifyreg16.c up_modifyreg32.c \
+			up_puts.c up_releasepending.c up_releasestack.c up_reprioritizertr.c \
+			up_schedulesigaction.c up_sigdeliver.c up_udelay.c up_unblocktask.c \
 			up_usestack.c
 
 # Configuration dependent common files
diff --git a/nuttx/configs/pcblogic-pic32mx/ostest/defconfig b/nuttx/configs/pcblogic-pic32mx/ostest/defconfig
index e357a9e356..0e74af970e 100644
--- a/nuttx/configs/pcblogic-pic32mx/ostest/defconfig
+++ b/nuttx/configs/pcblogic-pic32mx/ostest/defconfig
@@ -309,7 +309,7 @@ CONFIG_HAVE_LIBM=n
 CONFIG_DEBUG=n
 CONFIG_DEBUG_VERBOSE=n
 CONFIG_DEBUG_SYMBOLS=n
-CONFIG_MM_REGIONS=2
+CONFIG_MM_REGIONS=1
 CONFIG_ARCH_LOWPUTC=y
 CONFIG_RR_INTERVAL=200
 CONFIG_SCHED_INSTRUMENTATION=n