/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
 */

#include <sys/asm_linkage.h>
#include <brand_misc.h>

#if defined(lint)

/*ARGSUSED*/
void
brand_runexe(void *argv, ulong_t entry)
{
}

#else   /* lint */
        /*
         * Prepare to jump to the target program we actually want to run.
         * If this program is dynamically linked then we'll be jumping to
         * another copy of the linker.  If it's a statically linked program
         * we'll be jumping directy to it's main entry point.  In any case,
         * we need to reset our current state stack and register state to
         * something similar to the initial process state setup by the kernel
         * and documented at:
         *      usr/src/cmd/sgs/rtld/i386/boot.s
         *      usr/src/cmd/sgs/rtld/sparcv9/boot.s
         *
         * Of course this is the same stack format as when this executable
         * was first started, so here we'll just roll back the stack and
         * frame pointers to their values when this processes first started
         * execution.
         */
        ENTRY_NP(brand_runexe)

        movl    4(%esp), %eax           / %eax = &argv[0]
        movl    8(%esp), %ebx           / Brand app entry point in %ebx
        subl    $4, %eax                / Top of stack - must point at argc
        movl    %eax, %esp              / Set %esp to what linkers expect

        /*
         * We also have to make sure to clear %edx since nornally ld.so.1 will
         * set that to non-zero if there is an exit function that should be
         * invoked when the process is terminating.  This isn't actually
         * necessary if the target program we're jumping to is a dynamically
         * linked program since in that case we're actually jumping to another
         * copy of ld.so.1 and it will just reset %edx, but if the target
         * program we're jumping to is a statically linked binary that uses
         * the standard sun compiler supplied crt1.o`_start(), it will check
         * to see if %g1 is set.
         */
        movl    $0, %edx

        jmp     *%ebx                   / And away we go...
        /*
         * target will never return.
         */
        SET_SIZE(brand_runexe)
#endif  /* lint */