1/*-
2 * Copyright (c) 1998 Michael Smith <msmith@freebsd.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD: stable/11/stand/userboot/userboot/elf32_freebsd.c 261504 2014-02-05 04:39:03Z jhb $");
29
30#include <sys/param.h>
31#include <sys/exec.h>
32#include <sys/linker.h>
33#include <string.h>
34#define	_MACHINE_ELF_WANT_32BIT
35#include <i386/include/bootinfo.h>
36#include <i386/include/elf.h>
37#include <stand.h>
38
39#include "bootstrap.h"
40#include "libuserboot.h"
41
42static int	elf32_exec(struct preloaded_file *amp);
43static int	elf32_obj_exec(struct preloaded_file *amp);
44
45struct file_format i386_elf = { elf32_loadfile, elf32_exec };
46struct file_format i386_elf_obj = { elf32_obj_loadfile, elf32_obj_exec };
47
48#define	GUEST_STACK	0x1000		/* Initial stack base */
49#define	GUEST_GDT	0x3000		/* Address of initial GDT */
50
51/*
52 * There is an ELF kernel and one or more ELF modules loaded.
53 * We wish to start executing the kernel image, so make such
54 * preparations as are required, and do so.
55 */
56static int
57elf32_exec(struct preloaded_file *fp)
58{
59	struct file_metadata	*md;
60	Elf_Ehdr 		*ehdr;
61	vm_offset_t		entry, bootinfop, modulep, kernend;
62	int			boothowto, err, bootdev;
63	uint32_t		stack[1024], *sp;
64
65
66	if ((md = file_findmetadata(fp, MODINFOMD_ELFHDR)) == NULL)
67		return(EFTYPE);
68	ehdr = (Elf_Ehdr *)&(md->md_data);
69
70	err = bi_load32(fp->f_args, &boothowto, &bootdev, &bootinfop, &modulep, &kernend);
71	if (err != 0)
72		return(err);
73	entry = ehdr->e_entry & 0xffffff;
74
75#ifdef DEBUG
76	printf("Start @ 0x%lx ...\n", entry);
77#endif
78
79	dev_cleanup();
80
81	/*
82	 * Build a scratch stack at physical 0x1000
83	 */
84	memset(stack, 0, sizeof(stack));
85	sp = (uint32_t *)((char *)stack + sizeof(stack));
86	*--sp = kernend;
87	*--sp = modulep;
88	*--sp = bootinfop;
89	*--sp = 0;
90	*--sp = 0;
91	*--sp = 0;
92	*--sp = bootdev;
93	*--sp = boothowto;
94
95	/*
96	 * Fake return address to mimic "new" boot blocks.  For more
97	 * details see recover_bootinfo in locore.S.
98	 */
99	*--sp = 0xbeefface;
100	CALLBACK(copyin, stack, GUEST_STACK, sizeof(stack));
101	CALLBACK(setreg, 4, (char *)sp - (char *)stack + GUEST_STACK);
102
103	CALLBACK(setgdt, GUEST_GDT, 8 * 4 - 1);
104
105        CALLBACK(exec, entry);
106
107	panic("exec returned");
108}
109
110static int
111elf32_obj_exec(struct preloaded_file *fp)
112{
113	return (EFTYPE);
114}
115