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

5 files changed, 13 insertions, 8 deletions

diff --git a/nuttx/arch/x86/src/common/up_assert.c b/nuttx/arch/x86/src/common/up_assert.c
index 55ba376b4..776784656 100644
--- a/nuttx/arch/x86/src/common/up_assert.c
+++ b/nuttx/arch/x86/src/common/up_assert.c
@@ -198,7 +198,7 @@ static void up_dumpstate(void)
 
   if (current_regs != NULL)
     {
-      up_registerdump(current_regs);
+      up_registerdump((uint32_t*)current_regs);
 	}
 }
 #else
diff --git a/nuttx/arch/x86/src/common/up_internal.h b/nuttx/arch/x86/src/common/up_internal.h
index 51f79beb3..185d0afc0 100644
--- a/nuttx/arch/x86/src/common/up_internal.h
+++ b/nuttx/arch/x86/src/common/up_internal.h
@@ -99,7 +99,7 @@ typedef void (*up_vector_t)(void);
  * structure.  If is non-NULL only during interrupt processing.
  */
 
-extern uint32_t *current_regs;
+extern volatile uint32_t *current_regs;
 
 /* This is the beginning of heap as provided from up_head.S. This is the first
  * address in DRAM after the loaded program+bss+idle stack.  The end of the
diff --git a/nuttx/arch/x86/src/i486/up_irq.c b/nuttx/arch/x86/src/i486/up_irq.c
index 627c727de..01da4962e 100755
--- a/nuttx/arch/x86/src/i486/up_irq.c
+++ b/nuttx/arch/x86/src/i486/up_irq.c
@@ -72,7 +72,7 @@ static inline void up_idtinit(void);
  * Public Data
  ****************************************************************************/
 
-uint32_t *current_regs;
+volatile uint32_t *current_regs;
 
 /****************************************************************************
  * Private Data
diff --git a/nuttx/arch/x86/src/i486/up_savestate.c b/nuttx/arch/x86/src/i486/up_savestate.c
index d5f97fa85..1d35c62a9 100644
--- a/nuttx/arch/x86/src/i486/up_savestate.c
+++ b/nuttx/arch/x86/src/i486/up_savestate.c
@@ -80,7 +80,7 @@ void up_savestate(uint32_t *regs)
   
   /* First, just copy all of the registers */
 
-  up_copystate(regs, current_regs);
+  up_copystate(regs, (uint32_t*)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
diff --git a/nuttx/arch/x86/src/qemu/qemu_handlers.c b/nuttx/arch/x86/src/qemu/qemu_handlers.c
index fbcb327aa..a85370f76 100644
--- a/nuttx/arch/x86/src/qemu/qemu_handlers.c
+++ b/nuttx/arch/x86/src/qemu/qemu_handlers.c
@@ -86,6 +86,8 @@ static void idt_outb(uint8_t val, uint16_t addr)
 #ifndef CONFIG_SUPPRESS_INTERRUPTS
 static uint32_t *common_handler(int irq, uint32_t *regs)
 {
+  uint32_t *savestate;
+
   up_ledon(LED_INIRQ);
 
   /* Nested interrupts are not supported in this implementation.  If you want
@@ -98,7 +100,7 @@ static uint32_t *common_handler(int irq, uint32_t *regs)
    * current_regs is also used to manage interrupt level context switches.
    */
 
-  DEBUGASSERT(current_regs == NULL);
+  savestate    = (uint32_t*)current_regs;
   current_regs = regs;
 
   /* Deliver the IRQ */
@@ -111,11 +113,14 @@ static uint32_t *common_handler(int irq, uint32_t *regs)
    * switch occurred during interrupt processing.
    */
 
-  regs = current_regs;
+  regs = (uint32_t*)current_regs;
 
-  /* Indicate that we are no long in an interrupt handler */
+  /* 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.
+   */
 
-  current_regs = NULL;
+  current_regs = savestate;
   return regs;
 }
 #endif