Implement preliminary thread context

Three new modules are added :
 - kern/task: Tasks are thread groups and resource containers for their
   threads.
 - kern/thread: The well known scheduling unit.
 - x86/tcb: The architecture specific thread control block.

The kernel currently loads a single thread context on the main processor.

1 files changed, 58 insertions, 0 deletions

diff --git a/arch/x86/machine/tcb.h b/arch/x86/machine/tcb.h
new file mode 100644
index 00000000..96ac66a7
--- /dev/null
+++ b/arch/x86/machine/tcb.h
@@ -0,0 +1,58 @@
+/*
+ * Copyright (c) 2012 Richard Braun.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *
+ * Thread control block.
+ */
+
+#ifndef _X86_TCB_H
+#define _X86_TCB_H
+
+#include <kern/macros.h>
+#include <machine/trap.h>
+
+/*
+ * Forward declaration.
+ */
+struct thread;
+
+/*
+ * Architecture specific thread data.
+ */
+struct tcb {
+    struct trap_frame *frame;
+};
+
+/*
+ * Set up the tcb module.
+ */
+void tcb_setup(void);
+
+/*
+ * Create a TCB.
+ *
+ * Prepare the given stack for execution.
+ */
+int tcb_create(struct tcb **tcbp, void *stack, const struct thread *thread);
+
+/*
+ * Load a TCB.
+ *
+ * The caller context is lost.
+ */
+void __noreturn tcb_load(struct tcb *tcb);
+
+#endif /* _X86_TCB_H */