Add functions for libpayload to execute other payloads in memory,
and have those functions return cleanly.

Signed-off-by: Jordan Crouse <jordan.crouse@amd.com>
Index: libpayload/i386/Makefile.inc
===================================================================
--- libpayload.orig/i386/Makefile.inc	2008-05-13 13:40:07.000000000 -0600
+++ libpayload/i386/Makefile.inc	2008-05-13 13:42:59.000000000 -0600
@@ -29,3 +29,4 @@
 
 TARGETS-y += i386/head.o i386/main.o i386/sysinfo.o
 TARGETS-y += i386/timer.o i386/coreboot.o i386/util.o
+TARGETS-y += i386/exec.o
Index: libpayload/i386/exec.S
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ libpayload/i386/exec.S	2008-05-13 13:42:59.000000000 -0600
@@ -0,0 +1,64 @@
+/* calling syntax:  i386_do_exec(long addr, int argc, char **argv, int *ret) */
+
+.align 4
+.text
+
+.global i386_do_exec
+        .type i386_do_exec,@function
+
+i386_do_exec:
+	pushl %ebp
+        movl %esp, %ebp
+	pushl %eax
+
+	# Put the run address in %eax
+	movl 8(%ebp), %eax
+
+	# Save off the rest of the registers
+
+	pushl %esi
+	pushl %ecx
+	pushl %ebp
+
+	# Push the argc and argv pointers on to the stack
+
+	movl 12(%ebp), %esi
+	movl 16(%ebp), %ecx
+
+	pushl %esi
+	pushl %ecx
+
+	# Move a "magic" number on the stack - the other
+	# payload will use this as a clue that the argc
+	# and argv are sane
+
+	movl  $12345678, %ecx
+	pushl %ecx
+
+	# Jump to the code
+	call *%eax
+
+	/* %eax has the return value */
+
+	/* Skip over the argc/argv stuff still on the stack */
+	addl $12, %esp
+
+	# Get back %ebp
+	popl %ebp
+
+	# Get the pointer to the return value
+	# and save the return value in it
+
+	movl 20(%ebp), %ecx
+	movl %eax, (%eax)
+
+	# Get the rest of the saved registers
+	popl %ecx
+	popl %esi
+	popl %eax
+
+	# Restore the stack pointer
+	movl %ebp,%esp
+	popl %ebp
+	ret
+
Index: libpayload/i386/head.S
===================================================================
--- libpayload.orig/i386/head.S	2008-05-13 13:40:07.000000000 -0600
+++ libpayload/i386/head.S	2008-05-13 13:42:59.000000000 -0600
@@ -63,13 +63,14 @@
 
 	/* Let's rock. */
 	call start_main
-	
+
+	/* %eax has the return value - pass it on unmolested */
 _leave:
 	/* Get old stack pointer. */
 	popl %ebx
 
 	/* Restore old stack. */
-	movl %esp, %ebx
+	movl %ebx, %esp
 
 	/* Return to the original context. */
-	lret
+	ret
Index: libpayload/libc/exec.c
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ libpayload/libc/exec.c	2008-05-13 13:42:59.000000000 -0600
@@ -0,0 +1,52 @@
+/*
+ * This file is part of the libpayload project.
+ *
+ * Copyright (C) 2008 Advanced Micro Devices, Inc.
+ *
+ * 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. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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 <libpayload.h>
+
+#ifdef CONFIG_TARGET_I386
+extern void i386_do_exec(long, int, char **, int *);
+#endif
+
+/**
+ * Execute code in memory
+ *
+ * @param ptr The entry point to jump to
+ * @return Return the return value from the entry point
+ */
+
+
+int exec(long addr, int argc, char **argv)
+{
+	int val = -1;
+
+#ifdef CONFIG_TARGET_I386
+	i386_do_exec(addr, argc, argv, &val);
+#endif
+	return val;
+}
Index: libpayload/include/libpayload.h
===================================================================
--- libpayload.orig/include/libpayload.h	2008-05-13 13:42:59.000000000 -0600
+++ libpayload/include/libpayload.h	2008-05-13 13:42:59.000000000 -0600
@@ -145,6 +145,9 @@
 void *calloc(size_t nmemb, size_t size);
 void *realloc(void *ptr, size_t size);
 
+/* libc/exec.c */
+int exec(long addr, int argc, char **argv);
+
 /* libc/lib.c */
 int bcd2dec(int b);
 int dec2bcd(int d);
Index: libpayload/libc/Makefile.inc
===================================================================
--- libpayload.orig/libc/Makefile.inc	2008-05-13 13:40:07.000000000 -0600
+++ libpayload/libc/Makefile.inc	2008-05-13 13:42:59.000000000 -0600
@@ -29,4 +29,4 @@
 
 TARGETS-y += libc/malloc.o libc/printf.o libc/console.o libc/string.o
 TARGETS-y += libc/memory.o libc/ctype.o libc/ipchecksum.o libc/lib.o
-TARGETS-y += libc/rand.o libc/time.o libc/lar.o
+TARGETS-y += libc/rand.o libc/time.o libc/lar.o libc/exec.o

-- 
Jordan Crouse
Systems Software Development Engineer 
Advanced Micro Devices, Inc.



