Add group_addrenv() which will be called during context switches in order to change address environments. Not yet hooked in

1 files changed, 168 insertions, 0 deletions

diff --git a/nuttx/sched/group/group_addrenv.c b/nuttx/sched/group/group_addrenv.c
new file mode 100644
index 000000000..48e61fd4a
--- /dev/null
+++ b/nuttx/sched/group/group_addrenv.c
@@ -0,0 +1,168 @@
+/****************************************************************************
+ *  sched/group/group_addrenv.c
+ *
+ *   Copyright (C) 2014 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <gnutt@nuttx.org>
+ *
+ * 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 <debug.h>
+
+#include <nuttx/sched.h>
+
+#include "group/group.h"
+
+#ifdef CONFIG_ARCH_ADDRENV
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Data
+ ****************************************************************************/
+/* This variable holds the group ID of the current task group.  This ID is
+ * zero if the current task is a kernel thread that has no address
+ * environment (other than the kernel context).
+ *
+ * This must only be accessed with interrupts disabled.
+ */
+
+gid_t g_gid_current;
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: group_addrenv
+ *
+ * Description:
+ *   Instantiate the group address environment for the current thread at the
+ *   the head of the ready to run list.
+ *
+ *   This function is called from platform-specific code after any context
+ *   switch (i.e., after any change in the thread at the head of the ready-to-
+ *   run list).  This function will change the address environment if the
+ *   new thread is part of a different task group.
+ *
+ * Parameters:
+ *   tcb - The TCB of thread that needs an address environment.  This should
+ *         be the TCB at the head of the ready-to-run list, but that is not
+ *         enough.
+ *
+ * Return Value:
+ *   Zero (OK) is returned on success.  A negated errno value is returned on
+ *   any failure.
+ *
+ * Assumptions:
+ *   This function should only be called within critical OS sections with
+ *   interrupts disabled.  Interrupts are disabled internally just to be
+ *   certain, however.
+ *
+ ****************************************************************************/
+
+int group_addrenv(FAR struct tcb_s *tcb)
+{
+  FAR struct task_group_s *group;
+  FAR struct task_group_s *oldgroup;
+  irqstate_t flags;
+  gid_t gid;
+  int ret;
+
+  DEBUGASSERT(tcb && tcb->group);
+  group = tcb->group;
+
+  /* What is the ID of the group of the new thread to run?  Use zero if the
+   * group is a kernel thread.
+   */
+
+  gid = 0;
+  if ((tcb->flags & TCB_FLAG_TTYPE_MASK) != TCB_FLAG_TTYPE_KERNEL)
+    {
+      gid = group->tg_gid;
+    }
+
+  /* Are we going to change address environments? */
+
+  flags = irqsave();
+  if (gid != g_gid_current)
+    {
+      /* Yes.. Is there a current address environment in place? */
+
+      if (g_gid_current != 0)
+        {
+          /* Find the old group this this ID */
+
+          oldgroup = group_findbygid(g_gid_current);
+          DEBUGASSERT(oldgroup);
+
+          if (oldgroup)
+            {
+              /* We need to flush the D-Cache and Invalidate the I-Cache for
+               * the group whose environment is disappearing.
+               */
+
+              up_addrenv_coherent(&oldgroup->addrenv);
+            }
+        }
+
+      /* Instantiate the new address environment (removing the old
+       * environment in the process).  For the case of kernel threads,
+       * the old mappings will be removed and no new mappings will be
+       * instantiated.
+       */
+
+      ret = up_addrenv_select(&group->addrenv, NULL);
+      if (ret < 0)
+        {
+          bdbg("ERROR: up_addrenv_select failed: %d\n", ret);
+        }
+
+      /* Save the new, current group */
+  
+      g_gid_current = gid;
+    }
+
+  irqrestore(flags);
+  return OK;
+}
+
+#endif /* CONFIG_ARCH_ADDRENV */