Fix QEMU timer interrupt handler

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@3389 42af7a65-404d-4744-a932-0658087f49c3

1 files changed, 113 insertions, 0 deletions

diff --git a/nuttx/arch/x86/src/i486/up_savestate.c b/nuttx/arch/x86/src/i486/up_savestate.c
new file mode 100644
index 000000000..d5f97fa85
--- /dev/null
+++ b/nuttx/arch/x86/src/i486/up_savestate.c
@@ -0,0 +1,113 @@
+/****************************************************************************
+ * arch/x86/src/i486/up_savestate.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 <debug.h>
+
+#include <arch/arch.h>
+#include <arch/irq.h>
+
+#include "up_internal.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+/****************************************************************************
+ * Name: up_savestate
+ *
+ * Description:
+ *   This function saves the interrupt level context information in the
+ *   TCB.  This would just be a up_copystate but we have to handle one
+ *   special case.  In the case where the privilige level changes, the
+ *   value of sp and ss will not be saved on stack by the interrupt handler.
+ *   So, in that case, we will have to fudge those values here.
+ *
+ ****************************************************************************/
+
+void up_savestate(uint32_t *regs)
+{
+  uint8_t cpl;
+  uint8_t rpl;
+  
+  /* First, just copy all of the registers */
+
+  up_copystate(regs, current_regs);
+
+  /* The RES_SP and REG_SS values will not be saved by the interrupt handling
+   * logic if there is no change in privilege level.  In that case, we will
+   * have to "fudge" those values here.  For now, just overwrite the REG_SP
+   * and REG_SS values with what we believe to be correct.  Obviously, this
+   * will have to change in the future to support multi-segment operation.
+   *
+   * Check for a change in privilege level.
+   */
+
+  rpl = regs[REG_CS] & 3;
+  cpl = up_getcs() & 3;
+  DEBUGASSERT(rpl >= cpl);
+
+  if (rpl == cpl)
+    {
+      /* No priority change, SP and SS are not present in the stack frame.
+       *
+       * The value saved in the REG_ESP will be the stackpointer value prior to
+       * the execution of the PUSHA.  It will point at REG_IRQNO.
+       */
+
+      regs[REG_SP] = current_regs[REG_ESP] + 4*BOTTOM_NOPRIO;
+      regs[REG_SS] = up_getss();
+    }
+  else
+    {
+	  DEBUGASSERT(regs[REG_SP] == current_regs[REG_ESP] + 4*BOTTOM_PRIO);
+	}
+}