source: mainline/generic/src/lib/elf.c@ 56789125

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since 56789125 was cf26ba9, checked in by Jakub Jermar <jakub@…>, 19 years ago

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[de6b301]1/*
2 * Copyright (C) 2006 Sergey Bondari
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 *
9 * - Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * - Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * - The name of the author may not be used to endorse or promote products
15 * derived from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
[cf26ba9]29/**
30 * @file elf.c
31 * @brief Kernel ELF loader.
32 */
33
[de6b301]34#include <elf.h>
35#include <debug.h>
36#include <arch/types.h>
37#include <typedefs.h>
38#include <mm/as.h>
39#include <mm/frame.h>
[78a95d6f]40#include <mm/slab.h>
[de6b301]41#include <align.h>
[78a95d6f]42#include <memstr.h>
43#include <macros.h>
[de6b301]44
45static char *error_codes[] = {
46 "no error",
47 "invalid image",
48 "address space error",
49 "incompatible image",
50 "unsupported image type",
51 "irrecoverable error"
52};
53
[78a95d6f]54static int segment_header(elf_segment_header_t *entry, elf_header_t *elf, as_t *as);
55static int section_header(elf_section_header_t *entry, elf_header_t *elf, as_t *as);
56static int load_segment(elf_segment_header_t *entry, elf_header_t *elf, as_t *as);
[de6b301]57
58/** ELF loader
59 *
60 * @param header Pointer to ELF header in memory
61 * @param as Created and properly mapped address space
62 * @return EE_OK on success
63 */
64int elf_load(elf_header_t *header, as_t * as)
65{
66 int i, rc;
67
68 /* Identify ELF */
69 if (header->e_ident[EI_MAG0] != ELFMAG0 || header->e_ident[EI_MAG1] != ELFMAG1 ||
70 header->e_ident[EI_MAG2] != ELFMAG2 || header->e_ident[EI_MAG3] != ELFMAG3) {
71 return EE_INVALID;
72 }
73
74 /* Identify ELF compatibility */
75 if (header->e_ident[EI_DATA] != ELF_DATA_ENCODING || header->e_machine != ELF_MACHINE ||
76 header->e_ident[EI_VERSION] != EV_CURRENT || header->e_version != EV_CURRENT ||
77 header->e_ident[EI_CLASS] != ELF_CLASS) {
78 return EE_INCOMPATIBLE;
79 }
80
[78a95d6f]81 if (header->e_phentsize != sizeof(elf_segment_header_t))
82 return EE_INCOMPATIBLE;
83
84 if (header->e_shentsize != sizeof(elf_section_header_t))
[de6b301]85 return EE_INCOMPATIBLE;
86
87 /* Check if the object type is supported. */
88 if (header->e_type != ET_EXEC)
89 return EE_UNSUPPORTED;
90
[78a95d6f]91 /* Walk through all segment headers and process them. */
[de6b301]92 for (i = 0; i < header->e_phnum; i++) {
[78a95d6f]93 rc = segment_header(&((elf_segment_header_t *)(((__u8 *) header) + header->e_phoff))[i], header, as);
94 if (rc != EE_OK)
95 return rc;
96 }
97
98 /* Inspect all section headers and proccess them. */
99 for (i = 0; i < header->e_shnum; i++) {
100 rc = section_header(&((elf_section_header_t *)(((__u8 *) header) + header->e_shoff))[i], header, as);
[de6b301]101 if (rc != EE_OK)
102 return rc;
103 }
104
105 return EE_OK;
106}
107
108/** Print error message according to error code.
109 *
110 * @param rc Return code returned by elf_load().
111 *
112 * @return NULL terminated description of error.
113 */
114char *elf_error(int rc)
115{
116 ASSERT(rc < sizeof(error_codes)/sizeof(char *));
117
118 return error_codes[rc];
119}
120
[78a95d6f]121/** Process segment header.
[de6b301]122 *
[78a95d6f]123 * @param entry Segment header.
124 * @param elf ELF header.
[de6b301]125 * @param as Address space into wich the ELF is being loaded.
126 *
127 * @return EE_OK on success, error code otherwise.
128 */
[78a95d6f]129static int segment_header(elf_segment_header_t *entry, elf_header_t *elf, as_t *as)
[de6b301]130{
131 switch (entry->p_type) {
132 case PT_NULL:
133 case PT_PHDR:
134 break;
135 case PT_LOAD:
[78a95d6f]136 return load_segment(entry, elf, as);
[de6b301]137 break;
138 case PT_DYNAMIC:
139 case PT_INTERP:
140 case PT_SHLIB:
141 case PT_NOTE:
142 case PT_LOPROC:
143 case PT_HIPROC:
144 default:
145 return EE_UNSUPPORTED;
146 break;
147 }
148 return EE_OK;
149}
150
151/** Load segment described by program header entry.
152 *
153 * @param entry Program header entry describing segment to be loaded.
[78a95d6f]154 * @param elf ELF header.
[9179d0a]155 * @param as Address space into wich the ELF is being loaded.
[de6b301]156 *
157 * @return EE_OK on success, error code otherwise.
158 */
[78a95d6f]159int load_segment(elf_segment_header_t *entry, elf_header_t *elf, as_t *as)
[de6b301]160{
161 as_area_t *a;
[c23502d]162 int i, flags = 0;
[78a95d6f]163 size_t segment_size;
164 __u8 *segment;
[de6b301]165
166 if (entry->p_align > 1) {
167 if ((entry->p_offset % entry->p_align) != (entry->p_vaddr % entry->p_align)) {
168 return EE_INVALID;
169 }
170 }
171
[c23502d]172 if (entry->p_flags & PF_X)
173 flags |= AS_AREA_EXEC;
174 if (entry->p_flags & PF_W)
175 flags |= AS_AREA_WRITE;
176 if (entry->p_flags & PF_R)
177 flags |= AS_AREA_READ;
[de6b301]178
[78a95d6f]179 /*
180 * Check if the virtual address starts on page boundary.
181 */
182 if (ALIGN_UP(entry->p_vaddr, PAGE_SIZE) != entry->p_vaddr)
183 return EE_UNSUPPORTED;
184
185 segment_size = ALIGN_UP(max(entry->p_filesz, entry->p_memsz), PAGE_SIZE);
[5be1923]186 if ((entry->p_flags & PF_W)) {
187 /* If writable, copy data (should be COW in the future) */
188 segment = malloc(segment_size, 0);
[78a95d6f]189 memsetb((__address) (segment + entry->p_filesz), segment_size - entry->p_filesz, 0);
[5be1923]190 memcpy(segment, (void *) (((__address) elf) + entry->p_offset), entry->p_filesz);
191 } else /* Map identically original data */
192 segment = ((void *) elf) + entry->p_offset;
[78a95d6f]193
[a9e8b39]194 a = as_area_create(as, flags, entry->p_memsz, entry->p_vaddr, AS_AREA_ATTR_NONE);
[de6b301]195 if (!a)
[5a7d9d1]196 return EE_MEMORY;
[de6b301]197
198 for (i = 0; i < SIZE2FRAMES(entry->p_filesz); i++) {
[78a95d6f]199 as_set_mapping(as, entry->p_vaddr + i*PAGE_SIZE, KA2PA(((__address) segment) + i*PAGE_SIZE));
200 }
201
202 return EE_OK;
203}
204
205/** Process section header.
206 *
207 * @param entry Segment header.
208 * @param elf ELF header.
209 * @param as Address space into wich the ELF is being loaded.
210 *
211 * @return EE_OK on success, error code otherwise.
212 */
213static int section_header(elf_section_header_t *entry, elf_header_t *elf, as_t *as)
214{
215 switch (entry->sh_type) {
216 default:
217 break;
[de6b301]218 }
219
220 return EE_OK;
221}
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