Add task control syscalls.

10 files changed, 115 insertions, 8 deletions

diff --git a/src/include/kernel/syscalls.H b/src/include/kernel/syscalls.H
index a7a0ef6b7..826ac93b9 100644
--- a/src/include/kernel/syscalls.H
+++ b/src/include/kernel/syscalls.H
@@ -6,6 +6,9 @@ namespace Systemcalls
     enum SysCalls
     {
 	TASK_YIELD = 0,
+	TASK_START,
+	TASK_END,
+	TASK_GETTID,
 
 	SYSCALL_MAX
     };
diff --git a/src/include/kernel/task.H b/src/include/kernel/task.H
index d9256c365..4cd19bd04 100644
--- a/src/include/kernel/task.H
+++ b/src/include/kernel/task.H
@@ -23,4 +23,6 @@ struct task_t
     task_t* next;
 };
 
+enum { TASK_DEFAULT_STACK_SIZE = 4 };
+
 #endif
diff --git a/src/include/kernel/taskmgr.H b/src/include/kernel/taskmgr.H
index 34267324c..2bdb39c16 100644
--- a/src/include/kernel/taskmgr.H
+++ b/src/include/kernel/taskmgr.H
@@ -10,15 +10,14 @@ class TaskManager
 	static void setCurrentTask(task_t* t);
 	
 	typedef void(*task_fn_t)(void*);
+	static task_t* createTask(task_fn_t, void*);
 
 	friend class CpuManager;
-	friend class Kernel;
     protected:
 	TaskManager();
 	~TaskManager() {};
 
 	static task_t* createIdleTask();
-	static task_t* createTask(task_fn_t, void*);
 
     private:
 	tid_t getNextTid();
diff --git a/src/include/sys/syscall.h b/src/include/sys/syscall.h
index b418b5d15..36f84a51f 100644
--- a/src/include/sys/syscall.h
+++ b/src/include/sys/syscall.h
@@ -19,7 +19,7 @@ void* _syscall7(uint64_t, void*, void*, void*, void*, void*, void*, void*);
 
 #ifdef __cplusplus
 }
+#include <kernel/syscalls.H>
 #endif
 
-#include <kernel/syscalls.H>
 #endif
diff --git a/src/include/sys/task.h b/src/include/sys/task.h
new file mode 100644
index 000000000..84ddb10f9
--- /dev/null
+++ b/src/include/sys/task.h
@@ -0,0 +1,20 @@
+#ifndef __SYS_TASK_H
+#define __SYS_TASK_H
+
+#include <sys/syscall.h>
+
+#ifdef __cplusplus
+extern "C" 
+{
+#endif
+
+void task_yield();
+int task_create(void(*)(void*), void*);
+void task_end();
+
+uint64_t task_gettid();
+
+#ifdef __cplusplus
+}
+#endif
+#endif
diff --git a/src/kernel/syscall.C b/src/kernel/syscall.C
index 9cabeebd3..b993bf222 100644
--- a/src/kernel/syscall.C
+++ b/src/kernel/syscall.C
@@ -5,6 +5,7 @@
 #include <kernel/task.H>
 #include <kernel/syscalls.H>
 #include <kernel/console.H>
+#include <kernel/pagemgr.H>
 
 extern "C"
 void kernel_execute_decrementer()
@@ -22,10 +23,16 @@ namespace Systemcalls
 {
     typedef void(*syscall)(task_t*);
     void TaskYield(task_t*);
+    void TaskStart(task_t*);
+    void TaskEnd(task_t*);
+    void TaskGettid(task_t*);
 
     syscall syscalls[] =
 	{
 	    &TaskYield,
+	    &TaskStart,
+	    &TaskEnd,
+	    &TaskGettid,
 	};
 };
 
@@ -48,6 +55,18 @@ void kernel_execute_systemcall()
     }
 }
 
+#define TASK_GETARGN(t, n) (t->context.gprs[n+4])
+#define TASK_GETARG0(t) (TASK_GETARGN(t,0))
+#define TASK_GETARG1(t) (TASK_GETARGN(t,1))
+#define TASK_GETARG2(t) (TASK_GETARGN(t,2))
+#define TASK_GETARG3(t) (TASK_GETARGN(t,3))
+#define TASK_GETARG4(t) (TASK_GETARGN(t,4))
+#define TASK_GETARG5(t) (TASK_GETARGN(t,5))
+#define TASK_GETARG6(t) (TASK_GETARGN(t,6))
+#define TASK_GETARG7(t) (TASK_GETARGN(t,7))
+
+#define TASK_SETRTN(t, n) (t->context.gprs[3] = (n))
+
 namespace Systemcalls
 {
     void TaskYield(task_t* t)
@@ -56,4 +75,32 @@ namespace Systemcalls
 	s->returnRunnable();
 	s->setNextRunnable();
     }
+
+    void TaskStart(task_t* t)
+    {
+	task_t* newTask = 
+	    TaskManager::createTask((TaskManager::task_fn_t)TASK_GETARG0(t),
+				    (void*)TASK_GETARG1(t));
+	newTask->cpu = t->cpu;
+	t->cpu->scheduler->addTask(newTask);
+
+	TASK_SETRTN(t, newTask->tid);
+    }
+
+    void TaskEnd(task_t* t)
+    {
+	// Make sure task pointers are updated before we delete this task.
+	t->cpu->scheduler->setNextRunnable();
+	
+	// TODO: Deal with join.
+
+	// Clean up task memory.
+	PageManager::freePage(t->context.stack_ptr, TASK_DEFAULT_STACK_SIZE);
+	delete t;
+    }
+
+    void TaskGettid(task_t* t)
+    {
+	TASK_SETRTN(t, t->tid);
+    }
 };
diff --git a/src/kernel/taskmgr.C b/src/kernel/taskmgr.C
index fabb70cde..d060b0029 100644
--- a/src/kernel/taskmgr.C
+++ b/src/kernel/taskmgr.C
@@ -66,7 +66,8 @@ task_t* TaskManager::_createTask(TaskManager::task_fn_t t,
     // Setup stack.
     if (withStack)
     {
-	task->context.stack_ptr = PageManager::allocatePage(4);
+	task->context.stack_ptr = 
+	    PageManager::allocatePage(TASK_DEFAULT_STACK_SIZE);
 	task->context.gprs[1] = ((uint64_t)task->context.stack_ptr) + 16320;
     }
     else
diff --git a/src/lib/makefile b/src/lib/makefile
index 9ea27377e..1071dc75e 100644
--- a/src/lib/makefile
+++ b/src/lib/makefile
@@ -1,7 +1,8 @@
 OBJDIR = ../../obj
 include ../../config.mk
 
-OBJS = string.o stdlib.o syscall_stub.o
+OBJS = string.o stdlib.o 
+OBJS += syscall_stub.o syscall_task.o
 OBJECTS = $(addprefix ${OBJDIR}/, ${OBJS})
 
 all: ${OBJECTS}
diff --git a/src/lib/syscall_task.C b/src/lib/syscall_task.C
new file mode 100644
index 000000000..bfd522933
--- /dev/null
+++ b/src/lib/syscall_task.C
@@ -0,0 +1,26 @@
+#include <sys/task.h>
+#include <kernel/task.H>
+
+using namespace Systemcalls;
+
+void task_yield()
+{
+    _syscall0(TASK_YIELD);
+    return;
+}
+
+int task_create(void(*fn)(void*), void* ptr)
+{
+    return (int64_t) _syscall2(TASK_START, (void*)fn, ptr);
+}
+
+void task_end()
+{
+    _syscall0(TASK_END); // no return.
+    return;
+}
+
+uint64_t task_gettid()
+{
+    return (uint64_t)_syscall0(TASK_GETTID);
+}
diff --git a/src/sys/init/init_main.C b/src/sys/init/init_main.C
index e2447bc3f..8be5ae6c3 100644
--- a/src/sys/init/init_main.C
+++ b/src/sys/init/init_main.C
@@ -1,5 +1,12 @@
 #include <kernel/console.H>  // TODO : Remove this.
-#include <sys/syscall.h>     // TODO : Remove this.
+
+#include <sys/task.h>
+
+void init_child(void* unused)
+{
+    printk("Here I am %d\n", task_gettid());
+    task_end();
+}
 
 void init_main(void* unused)
 {
@@ -7,7 +14,8 @@ void init_main(void* unused)
 
     while(1)
     {
-	_syscall0(Systemcalls::TASK_YIELD);
-	for (volatile int i = 0 ; i < 100000; i++);
+	int t = task_create(&init_child, NULL);
+	printk("Created child %d\n", t);
+	for (volatile int i = 0 ; i < 10000000; i++);
     }
 }