current_regs should be volatile; add support for nested interrupts; enable interrupts during syscall processing

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@3475 42af7a65-404d-4744-a932-0658087f49c3

3 files changed, 28 insertions, 22 deletions

diff --git a/nuttx/arch/z16/src/common/up_doirq.c b/nuttx/arch/z16/src/common/up_doirq.c
index e7e43b24d..3adddf6db 100644
--- a/nuttx/arch/z16/src/common/up_doirq.c
+++ b/nuttx/arch/z16/src/common/up_doirq.c
@@ -1,7 +1,7 @@
 /****************************************************************************
  * common/up_doirq.c
  *
- *   Copyright (C) 2008-2009 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2008-2009, 2011 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -88,31 +88,37 @@ FAR chipreg_t *up_doirq(int irq, FAR chipreg_t *regs)
 #else
   if ((unsigned)irq < NR_IRQS)
     {
-       /* Current regs non-zero indicates that we are processing
-        * an interrupt; current_regs is also used to manage
-        * interrupt level context switches.
-        */
+      FAR chipreg_t *savestate;
 
-       current_regs = regs;
+      /* Current regs non-zero indicates that we are processing
+       * an interrupt; current_regs is also used to manage
+       * interrupt level context switches.
+       */
 
-       /* Mask and acknowledge the interrupt */
+      savestate    = (uint32_t*)current_regs;
+      current_regs = regs;
 
-       up_maskack_irq(irq);
+      /* Mask and acknowledge the interrupt */
 
-       /* Deliver the IRQ */
+      up_maskack_irq(irq);
 
-       irq_dispatch(irq, regs);
+      /* Deliver the IRQ */
 
-       /* Indicate that we are no long in an interrupt handler */
+      irq_dispatch(irq, regs);
 
-       ret          = current_regs;
-       current_regs = NULL;
+      /* Restore the previous value of current_regs.  NULL would indicate that
+       * we are no longer in an interrupt handler.  It will be non-NULL if we
+       * are returning from a nested interrupt.
+       */
 
-       /* Unmask the last interrupt (global interrupts are still
-        * disabled.
-        */
+      ret          = current_regs;
+      current_regs = savestate;
 
-       up_enable_irq(irq);
+      /* Unmask the last interrupt (global interrupts are still
+       * disabled.
+       */
+
+      up_enable_irq(irq);
     }
   up_ledoff(LED_INIRQ);
 #endif
diff --git a/nuttx/arch/z16/src/common/up_initialize.c b/nuttx/arch/z16/src/common/up_initialize.c
index 2121f73d9..063ccdf71 100644
--- a/nuttx/arch/z16/src/common/up_initialize.c
+++ b/nuttx/arch/z16/src/common/up_initialize.c
@@ -1,7 +1,7 @@
 /****************************************************************************
  * common/up_initialize.c
  *
- *   Copyright (C) 2008-2009 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2008-2009, 2011 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -68,7 +68,7 @@
  * interrupt processing.
  */
 
-FAR chipreg_t *current_regs;
+volatile FAR chipreg_t *current_regs;
 
 /****************************************************************************
  * Private Types
diff --git a/nuttx/arch/z16/src/common/up_internal.h b/nuttx/arch/z16/src/common/up_internal.h
index fa527fd62..117d7f405 100644
--- a/nuttx/arch/z16/src/common/up_internal.h
+++ b/nuttx/arch/z16/src/common/up_internal.h
@@ -1,7 +1,7 @@
 /****************************************************************************
  * common/up_internal.h
  *
- *   Copyright (C) 2008-2009 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2008-2009, 2011 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -74,7 +74,7 @@
 /* Macros for portability */
 
 #define IN_INTERRUPT             (current_regs != NULL)
-#define SAVE_IRQCONTEXT(tcb)     up_copystate((tcb)->xcp.regs, current_regs)
+#define SAVE_IRQCONTEXT(tcb)     up_copystate((tcb)->xcp.regs, (FAR chipreg_t*)current_regs)
 #define SET_IRQCONTEXT(tcb)      do { current_regs = (tcb)->xcp.regs; } while (0)
 #define SAVE_USERCONTEXT(tcb)    up_saveusercontext((tcb)->xcp.regs)
 #define RESTORE_USERCONTEXT(tcb) up_restoreusercontext((tcb)->xcp.regs)
@@ -98,7 +98,7 @@ typedef void (*up_vector_t)(void);
  * interrupt processing.
  */
 
-extern FAR chipreg_t *current_regs;
+extern voltile FAR chipreg_t *current_regs;
 #endif
 
 /****************************************************************************