savectx() is now used exclusively by the crash dump system. Move the

i386 specific gunk (copy %cr3 to the pcb) from the MI dumpsys() to the
MD savectx().

sys/amd64/amd64/cpu_switch.S

@@ -381,6 +381,9 @@ ENTRY(savectx)
 	movl	(%esp),%eax
 	movl	%eax,PCB_EIP(%ecx)
 
+	movl	%cr3,%eax
+	movl	%eax,PCB_CR3(%ecx)
+
 	movl	%ebx,PCB_EBX(%ecx)
 	movl	%esp,PCB_ESP(%ecx)
 	movl	%ebp,PCB_EBP(%ecx)

sys/amd64/amd64/swtch.s

@@ -381,6 +381,9 @@ ENTRY(savectx)
 	movl	(%esp),%eax
 	movl	%eax,PCB_EIP(%ecx)
 
+	movl	%cr3,%eax
+	movl	%eax,PCB_CR3(%ecx)
+
 	movl	%ebx,PCB_EBX(%ecx)
 	movl	%esp,PCB_ESP(%ecx)
 	movl	%ebp,PCB_EBP(%ecx)

sys/i386/i386/swtch.s

@@ -381,6 +381,9 @@ ENTRY(savectx)
 	movl	(%esp),%eax
 	movl	%eax,PCB_EIP(%ecx)
 
+	movl	%cr3,%eax
+	movl	%eax,PCB_CR3(%ecx)
+
 	movl	%ebx,PCB_EBX(%ecx)
 	movl	%esp,PCB_ESP(%ecx)
 	movl	%ebp,PCB_EBP(%ecx)

sys/kern/kern_shutdown.c

@@ -473,9 +473,6 @@ dumpsys(void)
 	int	error;
 
 	savectx(&dumppcb);
-#ifdef __i386__
-	dumppcb.pcb_cr3 = rcr3();
-#endif
 	if (dumping++) {
 		printf("Dump already in progress, bailing...\n");
 		return;