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diff --git a/payloads/libpayload/arch/x86/exec.S b/payloads/libpayload/arch/x86/exec.S
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+/*
+ * 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.
+ */
+
+/* calling syntax: i386_do_exec(long addr, int argc, char **argv, int *ret) */
+
+/* This implements the payload API detailed here:
+ * http://www.coreboot.org/Payload_API
+ */
+
+.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
+