1 /*-
2 * Copyright (c) 2005 Olivier Houchard. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
14 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
15 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
16 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
17 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
18 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
19 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
20 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
22 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
23 */
24
25 #include <sys/cdefs.h>
26 __FBSDID("$FreeBSD$");
27 #include <machine/asm.h>
28 #include <sys/param.h>
29
30 #ifdef __mips_n64
31 #include <sys/elf64.h>
32 #else
33 #include <sys/elf32.h>
34 #endif
35 #include <sys/inflate.h>
36 #include <machine/elf.h>
37 #include <machine/cpufunc.h>
38 #include <machine/stdarg.h>
39
40 /*
41 * Since we are compiled outside of the normal kernel build process, we
42 * need to include opt_global.h manually.
43 */
44 #include "opt_global.h"
45 #include "opt_kernname.h"
46
47 extern char kernel_start[];
48 extern char kernel_end[];
49
50 static __inline void *
51 memcpy(void *dst, const void *src, size_t len)
52 {
53 const char *s = src;
54 char *d = dst;
55
56 while (len) {
57 if (0 && len >= 4 && !((vm_offset_t)d & 3) &&
58 !((vm_offset_t)s & 3)) {
59 *(uint32_t *)d = *(uint32_t *)s;
60 s += 4;
61 d += 4;
62 len -= 4;
63 } else {
64 *d++ = *s++;
65 len--;
66 }
67 }
68 return (dst);
69 }
70
71 static __inline void
72 bzero(void *addr, size_t count)
73 {
74 char *tmp = (char *)addr;
75
76 while (count > 0) {
77 if (count >= 4 && !((vm_offset_t)tmp & 3)) {
78 *(uint32_t *)tmp = 0;
79 tmp += 4;
80 count -= 4;
81 } else {
82 *tmp = 0;
83 tmp++;
84 count--;
85 }
86 }
87 }
88
89 /*
90 * Relocate PT_LOAD segements of kernel ELF image to their respective
91 * virtual addresses and return entry point
92 */
93 void *
94 load_kernel(void * kstart)
95 {
96 #ifdef __mips_n64
97 Elf64_Ehdr *eh;
98 Elf64_Phdr phdr[64] /* XXX */;
99 Elf64_Shdr shdr[64] /* XXX */;
100 #else
101 Elf32_Ehdr *eh;
102 Elf32_Phdr phdr[64] /* XXX */;
103 Elf32_Shdr shdr[64] /* XXX */;
104 #endif
105 int i, j;
106 void *entry_point;
107 vm_offset_t lastaddr = 0;
108 int symtabindex = -1;
109 int symstrindex = -1;
110
111 #ifdef __mips_n64
112 eh = (Elf64_Ehdr *)kstart;
113 #else
114 eh = (Elf32_Ehdr *)kstart;
115 #endif
116 entry_point = (void*)eh->e_entry;
117 memcpy(phdr, (void *)(kstart + eh->e_phoff ),
118 eh->e_phnum * sizeof(phdr[0]));
119
120 memcpy(shdr, (void *)(kstart + eh->e_shoff),
121 sizeof(*shdr) * eh->e_shnum);
122
123 if (eh->e_shnum * eh->e_shentsize != 0 && eh->e_shoff != 0) {
124 for (i = 0; i < eh->e_shnum; i++) {
125 if (shdr[i].sh_type == SHT_SYMTAB) {
126 /*
127 * XXX: check if .symtab is in PT_LOAD?
128 */
129 if (shdr[i].sh_offset != 0 &&
130 shdr[i].sh_size != 0) {
131 symtabindex = i;
132 symstrindex = shdr[i].sh_link;
133 }
134 }
135 }
136 }
137
138 /*
139 * Copy loadable segments
140 */
141 for (i = 0; i < eh->e_phnum; i++) {
142 volatile char c;
143
144 if (phdr[i].p_type != PT_LOAD)
145 continue;
146
147 memcpy((void *)(phdr[i].p_vaddr),
148 (void*)(kstart + phdr[i].p_offset), phdr[i].p_filesz);
149
150 /* Clean space from oversized segments, eg: bss. */
151 if (phdr[i].p_filesz < phdr[i].p_memsz)
152 bzero((void *)(phdr[i].p_vaddr + phdr[i].p_filesz),
153 phdr[i].p_memsz - phdr[i].p_filesz);
154
155 if (lastaddr < phdr[i].p_vaddr + phdr[i].p_memsz)
156 lastaddr = phdr[i].p_vaddr + phdr[i].p_memsz;
157 }
158
159 /* Now grab the symbol tables. */
160 if (symtabindex >= 0 && symstrindex >= 0) {
161 *(Elf_Size *)lastaddr = SYMTAB_MAGIC;
162 lastaddr += sizeof(Elf_Size);
163 *(Elf_Size *)lastaddr = shdr[symtabindex].sh_size +
164 shdr[symstrindex].sh_size + 2*sizeof(Elf_Size);
165 lastaddr += sizeof(Elf_Size);
166 /* .symtab size */
167 *(Elf_Size *)lastaddr = shdr[symtabindex].sh_size;
168 lastaddr += sizeof(shdr[symtabindex].sh_size);
169 /* .symtab data */
170 memcpy((void*)lastaddr,
171 shdr[symtabindex].sh_offset + kstart,
172 shdr[symtabindex].sh_size);
173 lastaddr += shdr[symtabindex].sh_size;
174
175 /* .strtab size */
176 *(Elf_Size *)lastaddr = shdr[symstrindex].sh_size;
177 lastaddr += sizeof(shdr[symstrindex].sh_size);
178
179 /* .strtab data */
180 memcpy((void*)lastaddr,
181 shdr[symstrindex].sh_offset + kstart,
182 shdr[symstrindex].sh_size);
183 } else
184 /* Do not take any chances */
185 *(Elf_Size *)lastaddr = 0;
186
187 return entry_point;
188 }
189
190 void
191 _startC(register_t a0, register_t a1, register_t a2, register_t a3)
192 {
193 unsigned int * code;
194 int i;
195 void (*entry_point)(register_t, register_t, register_t, register_t);
196
197 /*
198 * Relocate segment to the predefined memory location
199 * Most likely it will be KSEG0/KSEG1 address
200 */
201 entry_point = load_kernel(kernel_start);
202
203 /* Pass saved registers to original _start */
204 entry_point(a0, a1, a2, a3);
205 }
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