libtf: separate scheduler fibre, change the core api

1 files changed, 47 insertions, 35 deletions

diff --git a/src/uctx.h b/src/uctx.h
index 541fcf9..e27a53c 100644
--- a/src/uctx.h
+++ b/src/uctx.h
@@ -14,8 +14,12 @@
 
 #include <stdio.h>
 #include <stdlib.h>
+
 #ifdef VALGRIND
 #include <valgrind/valgrind.h>
+#else
+#define VALGRIND_STACK_REGISTER(stack_base, size) 0
+#define VALGRIND_STACK_DEREGISTER(stack_id)
 #endif
 
 #define STACK_GUARD		0xbad57ac4
@@ -24,10 +28,7 @@ struct tf_uctx {
 	int *stack_guard;
 	void *alloc;
 	void *current_sp;
-#ifdef VALGRIND
 	unsigned int stack_id;
-#endif
-	struct tf_fiber fiber;
 };
 
 #if defined(__i386__)
@@ -86,10 +87,25 @@ static inline void stack_push_ptr(void **stackptr, void *ptr)
 }
 
 
-static inline
-struct tf_fiber *tf_uctx_create(tf_fiber_proc fiber_main, int private_size)
+static inline void tf_uctx_create_self(struct tf_uctx *uctx)
+{
+	static int dummy_guard = STACK_GUARD;
+
+	*uctx = (struct tf_uctx) {
+		.stack_guard = &dummy_guard,
+	};
+}
+
+static inline void *
+tf_uctx_create_embedded(
+	size_t stack_size,
+	size_t private_size,
+	off_t uctx_offset,
+	void (*stack_frame_main)(void*), off_t main_argument_offset,
+	void (*stack_frame_return)(void))
 {
 	size_t size = TF_STACK_SIZE;
+	void *user_data;
 	struct tf_uctx *uctx;
 	void *stack, *stack_base;
 
@@ -98,46 +114,42 @@ struct tf_fiber *tf_uctx_create(tf_fiber_proc fiber_main, int private_size)
 	if (stack_base == NULL)
 		return NULL;
 
+	/* Create initial stack frame (cdecl convention) */
 	stack = stack_pointer(stack_base, size);
-	private_size += sizeof(struct tf_uctx);
-
-	/* Construct inital frame for call the main function and if it
-	 * happens to return, it'll jump back to tf_exit() which kills
-	 * the fiber (cdecl calling convetion assumed) */
-	uctx = stack_push(&stack, TF_ALIGN(private_size, 64));
-	stack_push_ptr(&stack, uctx->fiber.data);
-	stack_push_ptr(&stack, &tf_exit);
-	stack_push_ptr(&stack, fiber_main);
-	uctx->current_sp = stack;
-
-#ifdef VALGRIND
-	uctx->stack_id = VALGRIND_STACK_REGISTER(stack_base, size);
-#endif
-	uctx->alloc = stack_base;
-	uctx->stack_guard = stack_guard(stack_base, size);
+	user_data = stack_push(&stack, TF_ALIGN(private_size, 64));
+	stack_push_ptr(&stack, NULL);
+	stack_push_ptr(&stack, NULL);
+	stack_push_ptr(&stack, NULL);
+	stack_push_ptr(&stack, NULL);
+	stack_push_ptr(&stack, user_data + main_argument_offset);
+	stack_push_ptr(&stack, stack_frame_return);
+	stack_push_ptr(&stack, stack_frame_main);
+
+	uctx = user_data + uctx_offset;
+	*uctx = (struct tf_uctx) {
+		.stack_guard = stack_guard(stack_base, size),
+		.alloc = stack_base,
+		.current_sp = stack,
+		.stack_id = VALGRIND_STACK_REGISTER(stack_base, size),
+	};
 	*uctx->stack_guard = STACK_GUARD;
 
-	return &uctx->fiber;
+	return user_data;
 }
 
 static inline
-void tf_uctx_destroy(struct tf_fiber *fiber)
+void tf_uctx_destroy(struct tf_uctx *uctx)
 {
-	struct tf_uctx *uctx = container_of(fiber, struct tf_uctx, fiber);
-#ifdef VALGRIND
-	VALGRIND_STACK_DEREGISTER(uctx->stack_id);
-#endif
-	free(uctx->alloc);
+	if (uctx->alloc != NULL) {
+		VALGRIND_STACK_DEREGISTER(uctx->stack_id);
+		free(uctx->alloc);
+	}
 }
 
 static inline
-void tf_uctx_transfer(struct tf_fiber *from, struct tf_fiber *to)
+void tf_uctx_transfer(struct tf_uctx *from, struct tf_uctx *to)
 {
-
-	struct tf_uctx *ufrom = container_of(from, struct tf_uctx, fiber);
-	struct tf_uctx *uto   = container_of(to,   struct tf_uctx, fiber);
-
 	/* Switch stack pointers */
-	TF_BUG_ON(*ufrom->stack_guard != STACK_GUARD);
-	switch_fiber(ufrom, uto);
+	TF_BUG_ON(*from->stack_guard != STACK_GUARD);
+	switch_fiber(from, to);
 }