Mutex test progress

- Mutex test added. Forked tasks demonstrate produce/consumer using a
  shared mmap'ed page.
- Added l4lib assembler syscall
- Added forgotten SWI to mutex control offset in syscall page.
- Added mutex head initialization
- Contended child successfully sleeps in a waitqueue.

Issues:
- Somehow the child's produced page buffer is altered at about [4020] offset.
  Parent fails to validate buffer therefore.
- Need to add syncing to test so that parent does not unlock and lock again
  before child has a chance to lock buffer and produce.

src/api/mutex.c

@@ -24,23 +24,29 @@ struct mutex_queue {
 
 struct mutex_queue_head {
 	struct list_head list;
+
+	/*
+	 * Lock for mutex_queue create/deletion and also list add/removal.
+	 * Both operations are done jointly so a single lock is enough.
+	 */
+	struct mutex mutex_control_mutex;
 	int count;
 } mutex_queue_head;
 
-/*
- * Lock for mutex_queue create/deletion and also list add/removal.
- * Both operations are done jointly so a single lock is enough.
- */
-struct mutex mutex_control_mutex;
-
+void init_mutex_queue_head(void)
+{
+	memset(&mutex_queue_head, 0, sizeof (mutex_queue_head));
+	INIT_LIST_HEAD(&mutex_queue_head.list);
+	mutex_init(&mutex_queue_head.mutex_control_mutex);
+}
 void mutex_queue_head_lock()
 {
-	mutex_lock(&mutex_control_mutex);
+	mutex_lock(&mutex_queue_head.mutex_control_mutex);
 }
 
 void mutex_queue_head_unlock()
 {
-	mutex_unlock(&mutex_control_mutex);
+	mutex_unlock(&mutex_queue_head.mutex_control_mutex);
 }
 
 

src/arch/arm/syscall.S

@@ -30,5 +30,6 @@ BEGIN_PROC(arm_system_calls)
 	swi	0x14		@ kread			/* 0x28 */
 	swi	0x14		@ kmem_control		/* 0x2C */
 	swi	0x14		@ time			/* 0x30 */
+	swi	0x14		@ mutex_control		/* 0x34 */
 END_PROC(arm_system_calls)
 

src/glue/arm/init.c

@@ -26,6 +26,7 @@
 #include INC_PLAT(printascii.h)
 #include INC_API(syscall.h)
 #include INC_API(kip.h)
+#include INC_API(mutex.h)
 
 unsigned int kernel_mapping_end;
 
@@ -344,6 +345,7 @@ void init_tasks()
 	/* Initialise the global task and address space lists */
 	init_ktcb_list();
 	init_address_space_list();
+	init_mutex_queue_head();
 
 	printk("%s: Initialized. Starting %s as pager.\n",
 	       __KERNELNAME__, __PAGERNAME__);

src/glue/arm/systable.c

@@ -54,7 +54,7 @@ void syscall_init()
 	syscall_table[sys_kread_offset >> 2]		 	= (syscall_fn_t)sys_kread;
 	syscall_table[sys_kmem_control_offset >> 2]		= (syscall_fn_t)sys_kmem_control;
 	syscall_table[sys_time_offset >> 2]			= (syscall_fn_t)sys_time;
-	syscall_table[sys_mutex_control_offset >> 2]			= (syscall_fn_t)sys_mutex_control;
+	syscall_table[sys_mutex_control_offset >> 2]		= (syscall_fn_t)sys_mutex_control;
 
 	add_mapping(virt_to_phys(&__syscall_page_start),
 		    ARM_SYSCALL_PAGE, PAGE_SIZE, MAP_USR_RO_FLAGS);