Initial Spring 2016 commit.

2015-12-23 00:50:04 +00:00
commit cafa9f5690
732 changed files with 92195 additions and 0 deletions
--- a/kern/arch/mips/thread/switchframe.c
+++ b/kern/arch/mips/thread/switchframe.c
@@ -0,0 +1,98 @@
+/*
+ * Copyright (c) 2000, 2001, 2002, 2003, 2004, 2005, 2008, 2009
+ *	The President and Fellows of Harvard College.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE UNIVERSITY OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <types.h>
+#include <lib.h>
+#include <thread.h>
+#include <threadprivate.h>
+
+#include "switchframe.h"
+
+/* in threadstart.S */
+extern void mips_threadstart(/* arguments are in unusual registers */);
+
+
+/*
+ * Function to initialize the switchframe of a new thread, which is
+ * *not* the one that is currently running.
+ *
+ * The new thread should, when it is run the first time, end up calling
+ * thread_startup(entrypoint, data1, data2).
+ *
+ * We arrange for this by creating a phony switchframe for
+ * switchframe_switch() to switch to. The only trouble is that the
+ * switchframe doesn't include the argument registers a0-a3. So we
+ * store the arguments in the s* registers, and use a bit of asm
+ * (mips_threadstart) to move them and then jump to thread_startup.
+ */
+void
+switchframe_init(struct thread *thread,
+		 void (*entrypoint)(void *data1, unsigned long data2),
+		 void *data1, unsigned long data2)
+{
+	vaddr_t stacktop;
+	struct switchframe *sf;
+
+        /*
+         * MIPS stacks grow down. t_stack is just a hunk of memory, so
+         * get the other end of it. Then set up a switchframe on the
+         * top of the stack.
+         */
+        stacktop = ((vaddr_t)thread->t_stack) + STACK_SIZE;
+        sf = ((struct switchframe *) stacktop) - 1;
+
+        /* Zero out the switchframe. */
+        bzero(sf, sizeof(*sf));
+
+        /*
+         * Now set the important parts: pass through the three arguments,
+         * and set the return address register to the place we want
+         * execution to begin.
+         *
+         * Thus, when switchframe_switch does its "j ra", it will
+         * actually jump to mips_threadstart, which will move the
+         * arguments into the right register and jump to
+         * thread_startup().
+         *
+         * Note that this means that when we call switchframe_switch()
+         * in thread_switch(), we may not come back out the same way
+         * in the next thread. (Though we will come back out the same
+         * way when we later come back to the same thread again.)
+         *
+         * This has implications for code at the bottom of
+         * thread_switch, described in thread.c.
+         */
+        sf->sf_s0 = (uint32_t)entrypoint;
+        sf->sf_s1 = (uint32_t)data1;
+        sf->sf_s2 = (uint32_t)data2;
+        sf->sf_ra = (uint32_t)mips_threadstart;
+
+        /* Set ->t_context, and we're done. */
+	thread->t_context = sf;
+}