x86: add thread support

Thread support is added for the x86 architecture. Both
the local apic and the tsc udelay() functions have a
call to thread_yield_microseconds() so as to provide an
opportunity to run pending threads.

Change-Id: Ie39b9eb565eb189676c06645bdf2a8720fe0636a
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/3207
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

1 files changed, 58 insertions, 0 deletions

diff --git a/src/arch/x86/lib/thread.c b/src/arch/x86/lib/thread.c
new file mode 100644
index 0000000000..06f8a154e2
--- /dev/null
+++ b/src/arch/x86/lib/thread.c
@@ -0,0 +1,58 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2013 Google, Inc.
+ *
+ * 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; version 2 of the License.
+ *
+ * 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, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <thread.h>
+
+/* The stack frame looks like the following after a pushad instruction. */
+struct pushad_regs {
+	uint32_t edi; /* Offset 0x00 */
+	uint32_t esi; /* Offset 0x04 */
+	uint32_t ebp; /* Offset 0x08 */
+	uint32_t esp; /* Offset 0x0c */
+	uint32_t ebx; /* Offset 0x10 */
+	uint32_t edx; /* Offset 0x14 */
+	uint32_t ecx; /* Offset 0x18 */
+	uint32_t eax; /* Offset 0x1c */
+};
+
+static inline uintptr_t push_stack(uintptr_t cur_stack, uintptr_t value)
+{
+	uintptr_t *addr;
+
+	cur_stack -= sizeof(value);
+	addr = (uintptr_t *)cur_stack;
+	*addr = value;
+	return cur_stack;
+}
+
+void arch_prepare_thread(struct thread *t,
+                         void asmlinkage (*thread_entry)(void *), void *arg)
+{
+	uintptr_t stack = t->stack_current;
+
+	/* Imitate thread_entry(t) with return address of 0. thread_entry()
+	 * is assumed to never return. */
+	stack = push_stack(stack, (uintptr_t)arg);
+	stack = push_stack(stack, (uintptr_t)0);
+	stack = push_stack(stack, (uintptr_t)thread_entry);
+	/* Make room for the registers. Ignore intial values. */
+	stack -= sizeof(struct pushad_regs);
+
+	t->stack_current = stack;
+}