misc QEMU fixes

git-svn-id: https://nuttx.svn.sourceforge.net/svnroot/nuttx/trunk@3351 7fd9a85b-ad96-42d3-883c-3090e2eb8679

4 files changed, 77 insertions, 29 deletions

diff --git a/nuttx/arch/x86/include/i486/arch.h b/nuttx/arch/x86/include/i486/arch.h
index e2dde5555f..5910f08a15 100755
--- a/nuttx/arch/x86/include/i486/arch.h
+++ b/nuttx/arch/x86/include/i486/arch.h
@@ -163,6 +163,44 @@ static inline uint32_t up_getsp()
   return regval;
 }
 
+/* Get segment registers */
+
+static inline uint32_t up_getds()
+{
+  uint32_t regval;
+
+  asm volatile(
+    "\tmov %%ds, %0\n"
+    : "=rm" (regval)
+    :
+    : "memory");
+  return regval;
+}
+
+static inline uint32_t up_getcs()
+{
+  uint32_t regval;
+
+  asm volatile(
+    "\tmov %%cs, %0\n"
+    : "=rm" (regval)
+    :
+    : "memory");
+  return regval;
+}
+
+static inline uint32_t up_getss()
+{
+  uint32_t regval;
+
+  asm volatile(
+    "\tmov %%ss, %0\n"
+    : "=rm" (regval)
+    :
+    : "memory");
+  return regval;
+}
+
 /****************************************************************************
  * Public Types
  ****************************************************************************/
diff --git a/nuttx/arch/x86/src/i486/i486_utils.S b/nuttx/arch/x86/src/i486/i486_utils.S
index eae168fbd6..9010b5a711 100644
--- a/nuttx/arch/x86/src/i486/i486_utils.S
+++ b/nuttx/arch/x86/src/i486/i486_utils.S
@@ -52,6 +52,8 @@
 # define SYMBOL(s) s
 #endif
 
+#define KSEG 0x10
+
 /****************************************************************************
  * Nasm
  ****************************************************************************/
@@ -84,12 +86,12 @@ SYMBOL(gdt_flush):
     mov		eax, [esp+4]		/* Get the pointer to the GDT, passed as a parameter */
     lgdt	[eax]				/* Load the new GDT pointer */
 
-    mov		ax, 0x10			/* 0x10 is the offset in the GDT to our data segment */
-    mov		ds, ax				/* Load all data segment selectors */
-    mov		es, ax
-    mov		fs, ax
-    mov		gs, ax
-    mov		ss, ax
+    mov		$KSEG, ax 			/* KSEG is the offset in the GDT to our data segment */
+    mov		ax, ds				/* Load all data segment selectors */
+    mov		ax, es
+    mov		ax, fs
+    mov		ax, gs
+    mov		ax, ss
     jmp		0x08:.gflush		/* 0x08 is the offset to our code segment: Far jump! */
 .gflush:
     ret
@@ -135,12 +137,12 @@ SYMBOL(gdt_flush):
     movl	%eax, 4(%esp)	/* Get the pointer to the GDT, passed as a parameter */
     lgdt	(%eax)			/* Load the new GDT pointer */
 
-    mov		%ax, 0x10		/* 0x10 is the offset in the GDT to our data segment */
-    mov		%ds, %ax		/* Load all data segment selectors */
-    mov		%es, %ax
-    mov		%fs, %ax
-    mov		%gs, %ax
-    mov		%ss, %ax
+    mov		$KSEG, %ax 		/* KSEG is the offset in the GDT to our data segment */
+    mov		%ax, %ds 		/* Load all data segment selectors */
+    mov		%ax, %es
+    mov		%ax, %fs
+    mov		%ax, %gs
+    mov		%ax, %ss
     jmp		$0x08, $.Lgflush		/* 0x08 is the offset to our code segment: Far jump! */
 .Lgflush:
     ret
diff --git a/nuttx/arch/x86/src/i486/up_initialstate.c b/nuttx/arch/x86/src/i486/up_initialstate.c
index 6e7417d5c3..1a13b89915 100644
--- a/nuttx/arch/x86/src/i486/up_initialstate.c
+++ b/nuttx/arch/x86/src/i486/up_initialstate.c
@@ -93,6 +93,14 @@ void up_initial_state(_TCB *tcb)
 
   xcp->regs[REG_EIP]     = (uint32_t)tcb->start;
 
+  /* Set up the segment registers... assume the same segment as the caller.
+   * That is not a good assumption in the long run.
+   */
+
+  xcp->regs[REG_DS]      = up_getds();
+  xcp->regs[REG_CS]      = up_getcs();
+  xcp->regs[REG_SS]      = up_getss();
+
   /* Enable or disable interrupts, based on user configuration.  If the IF
    * bit is set, maskable interrupts will be enabled.
    */
diff --git a/nuttx/arch/x86/src/qemu/qemu_vectors.S b/nuttx/arch/x86/src/qemu/qemu_vectors.S
index 6795203e26..55aabaf39a 100755
--- a/nuttx/arch/x86/src/qemu/qemu_vectors.S
+++ b/nuttx/arch/x86/src/qemu/qemu_vectors.S
@@ -408,14 +408,14 @@ isr_common:
 /*	trace	'S' */
 	pusha						/* Pushes edi,esi,ebp,esp,ebx,edx,ecx,eax */
 
-	mov		%ax, %ds			/* Lower 16-bits of eax = ds. */
+	mov		%ds, %ax			/* Lower 16-bits of eax = ds. */
 	pushl	%eax				/* Save the data segment descriptor */
 
-	mov		%ax, KSEG			/* Load the kernel data segment descriptor */
-	mov		%ds, %ax
-	mov		%es, %ax
-	mov		%fs, %ax
-	mov		%gs, %ax
+	mov		$KSEG, %ax 			/* Load the kernel data segment descriptor */
+	mov		%ax, %ds
+	mov		%ax, %es
+	mov		%ax, %fs
+	mov		%ax, %gs
 
 	/* The current value of the SP points to the beginning of the state save
 	 * structure.  Save that on the stack as the input parameter to isr_handler.
@@ -446,14 +446,14 @@ irq_common:
 /*	trace	'R' */
 	pusha						/* Pushes edi,esi,ebp,esp,ebx,edx,ecx,eax */
 
-	mov		%ax, %ds				/* Lower 16-bits of eax = ds. */
+	mov		%ds, %ax			/* Lower 16-bits of eax = ds. */
 	push	%eax				/* Save the data segment descriptor */
 
-	mov		%ax, KSEG			/* Load the kernel data segment descriptor */
-	mov		%ds, %ax
-	mov		%es, %ax
-	mov		%fs, %ax
-	mov		%gs, %ax
+	mov		$KSEG, %ax 			/* Load the kernel data segment descriptor */
+	mov		%ax, %ds
+	mov		%ax, %es
+	mov		%ax, %fs
+	mov		%ax, %gs
 
 	/* The current value of the SP points to the beginning of the state save
 	 * structure.  Save that on the stack as the input parameter to irq_handler.
@@ -488,13 +488,13 @@ irq_common:
 
 .Lnoswitch:
 	pop		%ebx				/* Reload the original data segment descriptor */
-	mov		%ds, %bx
-	mov		%es, %bx
-	mov		%fs, %bx
-	mov		%gs, %bx
+	mov		%bx, %ds
+	mov		%bx, %es
+	mov		%bx, %fs
+	mov		%bx, %gs
 
 	popa						/* Pops edi,esi,ebp... */
-	add		%esp, 8				/* Cleans up the pushed error code and pushed ISR number */
+	add		$8, %esp			/* Cleans up the pushed error code and pushed ISR number */
 	sti
 	iret						/* Pops 5 things at once: CS, EIP, EFLAGS, SS, and ESP */
 #ifndef __CYGWIN__