Add a up_stack_frame() interface to allocate a frame of data on a task's stack.

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@5768 42af7a65-404d-4744-a932-0658087f49c3

1 files changed, 134 insertions, 0 deletions

diff --git a/nuttx/arch/x86/src/i486/up_stackframe.c b/nuttx/arch/x86/src/i486/up_stackframe.c
new file mode 100644
index 000000000..ea4edc07a
--- /dev/null
+++ b/nuttx/arch/x86/src/i486/up_stackframe.c
@@ -0,0 +1,134 @@
+/****************************************************************************
+ * arch/x86/src/i486/up_stackframe.c
+ *
+ *   Copyright (C) 2013 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 <sys/types.h>
+#include <stdint.h>
+#include <sched.h>
+#include <debug.h>
+
+#include <nuttx/arch.h>
+
+#include "up_internal.h"
+
+/****************************************************************************
+ * Pre-processor Macros
+ ****************************************************************************/
+
+/* The initial stack point is aligned at word (4 byte) boundaries. If
+ * necessary frame_size must be rounded up to the next boundary to retain
+ * this alignment.
+ */
+
+#define STACK_ALIGNMENT     4
+
+/* Stack alignment macros */
+
+#define STACK_ALIGN_MASK    (STACK_ALIGNMENT-1)
+#define STACK_ALIGN_DOWN(a) ((a) & ~STACK_ALIGN_MASK)
+#define STACK_ALIGN_UP(a)   (((a) + STACK_ALIGN_MASK) & ~STACK_ALIGN_MASK)
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Global Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: up_stack_frame
+ *
+ * Description:
+ *   Allocate a stack frame in the TCB's stack to hold thread-specific data.
+ *   This function may be called anytime after up_create_stack() or
+ *   up_use_stack() have been called but before the task has been started.
+ *
+ *   Thread data may be kept in the stack (instead of in the TCB) if it is
+ *   accessed by the user code directory.  This includes such things as
+ *   argv[].  The stack memory is guaranteed to be in the same protection
+ *   domain as the thread.
+ *
+ *   The following TCB fields will be re-initialized:
+ *
+ *   - adj_stack_size: Stack size after removal of the stack frame from
+ *     the stack
+ *   - adj_stack_ptr: Adjusted initial stack pointer after the frame has
+ *     been removed from the stack.  This will still be the initial value
+ *     of the stack pointer when the task is started.
+ *
+ * Inputs:
+ *   - tcb:  The TCB of new task
+ *   - frame_size:  The size of the stack frame to allocate.
+ *
+ *  Returned Value:
+ *   - A pointer to bottom of the allocated stack frame.  NULL will be
+ *     returned on any failures.  The alignment of the returned value is
+ *     the same as the alignment of the stack itself.
+ *
+ ****************************************************************************/
+
+FAR void *up_stack_frame(FAR struct tcb_s *tcb, size_t frame_size)
+{
+  uintptr_t topaddr;
+
+  /* Align the frame_size */
+
+  frame_size = STACK_ALIGN_UP(frame_size);
+  
+  /* Is there already a stack allocated? Is it big enough? */
+
+  if (!tcb->stack_alloc_ptr || tcb->adj_stack_size <= frame_size)
+    {
+      return NULL;
+    }
+
+  /* Save the adjusted stack values in the struct tcb_s */
+
+  topaddr              = (uintptr_t)tcb->adj_stack_ptr - frame_size;
+  tcb->adj_stack_ptr   = (FAR void *)topaddr;
+  tcb->adj_stack_size -= frame_size;
+
+  return (FAR void *)(topaddr + sizeof(uint32_t));
+}