exchange_registers(), modified thread_control calls seem to work

- Fixed do_mmap() so that it returns mapped address, and various bugs.
- A child seems to fork with new setup, but with incorrect return value.
  Need to use and test exregs() for fork + clone.
- Shmat searches an unmapped area if input arg is invalid, do_mmap()
  should do this.

include/l4/api/exregs.h

@@ -11,10 +11,16 @@
 #include INC_GLUE(context.h)
 #include <l4/types.h>
 
+enum exregs_flags {
+	EXREGS_SET_PAGER = 1,
+};
+
 /* Structure passed by userspace pagers for exchanging registers */
 struct exregs_data {
 	exregs_context_t context;
 	u32 valid_vect;
+	u32 flags;
+	l4id_t pagerid;
 };
 
 

include/l4/arch/arm/exception.h

@@ -75,16 +75,9 @@ static inline void irq_local_disable()
 /* This is filled on entry to irq handler, only if a process was interrupted.*/
 extern unsigned int preempted_psr;
 
-#include <l4/generic/tcb.h>
-static inline int task_in_kernel(struct tcb *t)
-{
-	return ((t->context.spsr & ARM_MODE_MASK) == ARM_MODE_SVC) ? 1 : 0;
-}
-
-static inline int task_in_user(struct tcb *t)
-{
-	return !task_in_kernel(t);
-}
+/* Implementing these as functions cause circular include dependency for tcb.h */
+#define TASK_IN_KERNEL(tcb)	(((tcb)->context.spsr & ARM_MODE_MASK) == ARM_MODE_SVC)
+#define TASK_IN_USER(tcb)	(!TASK_IN_KERNEL(tcb))
 
 static inline int in_kernel()
 {

include/l4/generic/scheduler.h

@@ -35,6 +35,7 @@ static inline struct ktcb *current_task(void)
 					 | SCHED_FL_SUSPEND)
 
 void sched_runqueue_init(void);
+void sched_init_task(struct ktcb *task);
 void sched_start_task(struct ktcb *task);
 void sched_resume_task(struct ktcb *task);
 void sched_suspend_task(struct ktcb *task);

include/l4/generic/tcb.h

@@ -102,12 +102,6 @@ static inline int add_task_global(struct ktcb *new)
 	return 0;
 }
 
-
-static inline void set_task_flags(struct ktcb *task, unsigned int fl)
-{
-	task->flags |= fl;
-}
-
 /*
  * Each task is allocated a unique global id. A thread group can only belong to
  * a single leader, and every thread can only belong to a single thread group.

include/l4/glue/arm/context.h

@@ -5,10 +5,10 @@
 
 /*
  * This describes the register context of each task. Simply set
- * them as regular structure fields, and they'll be copied onto
- * real registers upon a context switch to that task. Normally
- * exchange_registers() system call is designed for this, whose
- * input structure is defined further below.
+ * them and they'll be copied onto real registers upon a context
+ * switch to that task. exchange_registers() system call is
+ * designed for this, whose input structure is defined further
+ * below.
  */
 typedef struct arm_context {
 	u32 spsr;	/* 0x0 */