2
* Copyright (c) 2006 Sergey Bondari
3
* Copyright (c) 2006 Jakub Jermar
6
* Redistribution and use in source and binary forms, with or without
7
* modification, are permitted provided that the following conditions
10
* - Redistributions of source code must retain the above copyright
11
* notice, this list of conditions and the following disclaimer.
12
* - Redistributions in binary form must reproduce the above copyright
13
* notice, this list of conditions and the following disclaimer in the
14
* documentation and/or other materials provided with the distribution.
15
* - The name of the author may not be used to endorse or promote products
16
* derived from this software without specific prior written permission.
18
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30
/** @addtogroup generic
36
* @brief Kernel ELF loader.
41
#include <arch/types.h>
50
static char *error_codes[] = {
53
"address space error",
55
"unsupported image type",
59
static int segment_header(elf_segment_header_t *entry, elf_header_t *elf,
61
static int section_header(elf_section_header_t *entry, elf_header_t *elf,
63
static int load_segment(elf_segment_header_t *entry, elf_header_t *elf,
68
* @param header Pointer to ELF header in memory
69
* @param as Created and properly mapped address space
70
* @param flags A combination of ELD_F_*
71
* @return EE_OK on success
73
unsigned int elf_load(elf_header_t *header, as_t * as, int flags)
78
if (header->e_ident[EI_MAG0] != ELFMAG0 ||
79
header->e_ident[EI_MAG1] != ELFMAG1 ||
80
header->e_ident[EI_MAG2] != ELFMAG2 ||
81
header->e_ident[EI_MAG3] != ELFMAG3) {
85
/* Identify ELF compatibility */
86
if (header->e_ident[EI_DATA] != ELF_DATA_ENCODING ||
87
header->e_machine != ELF_MACHINE ||
88
header->e_ident[EI_VERSION] != EV_CURRENT ||
89
header->e_version != EV_CURRENT ||
90
header->e_ident[EI_CLASS] != ELF_CLASS) {
91
return EE_INCOMPATIBLE;
94
if (header->e_phentsize != sizeof(elf_segment_header_t))
95
return EE_INCOMPATIBLE;
97
if (header->e_shentsize != sizeof(elf_section_header_t))
98
return EE_INCOMPATIBLE;
100
/* Check if the object type is supported. */
101
if (header->e_type != ET_EXEC)
102
return EE_UNSUPPORTED;
104
/* Check if the ELF image starts on a page boundary */
105
if (ALIGN_UP((uintptr_t)header, PAGE_SIZE) != (uintptr_t)header)
106
return EE_UNSUPPORTED;
108
/* Walk through all segment headers and process them. */
109
for (i = 0; i < header->e_phnum; i++) {
110
elf_segment_header_t *seghdr;
112
seghdr = &((elf_segment_header_t *)(((uint8_t *) header) +
113
header->e_phoff))[i];
114
rc = segment_header(seghdr, header, as, flags);
119
/* Inspect all section headers and proccess them. */
120
for (i = 0; i < header->e_shnum; i++) {
121
elf_section_header_t *sechdr;
123
sechdr = &((elf_section_header_t *)(((uint8_t *) header) +
124
header->e_shoff))[i];
125
rc = section_header(sechdr, header, as);
133
/** Print error message according to error code.
135
* @param rc Return code returned by elf_load().
137
* @return NULL terminated description of error.
139
char *elf_error(unsigned int rc)
141
ASSERT(rc < sizeof(error_codes) / sizeof(char *));
143
return error_codes[rc];
146
/** Process segment header.
148
* @param entry Segment header.
149
* @param elf ELF header.
150
* @param as Address space into wich the ELF is being loaded.
152
* @return EE_OK on success, error code otherwise.
154
static int segment_header(elf_segment_header_t *entry, elf_header_t *elf,
159
switch (entry->p_type) {
164
return load_segment(entry, elf, as);
168
interp = (char *)elf + entry->p_offset;
170
/*if (memcmp((uintptr_t)interp, (uintptr_t)ELF_INTERP_ZSTR,
171
ELF_INTERP_ZLEN) != 0) {
172
return EE_UNSUPPORTED;
174
if ((flags & ELD_F_LOADER) == 0) {
183
return EE_UNSUPPORTED;
189
/** Load segment described by program header entry.
191
* @param entry Program header entry describing segment to be loaded.
192
* @param elf ELF header.
193
* @param as Address space into wich the ELF is being loaded.
195
* @return EE_OK on success, error code otherwise.
197
int load_segment(elf_segment_header_t *entry, elf_header_t *elf, as_t *as)
201
mem_backend_data_t backend_data;
205
backend_data.elf = elf;
206
backend_data.segment = entry;
208
if (entry->p_align > 1) {
209
if ((entry->p_offset % entry->p_align) !=
210
(entry->p_vaddr % entry->p_align)) {
215
if (entry->p_flags & PF_X)
216
flags |= AS_AREA_EXEC;
217
if (entry->p_flags & PF_W)
218
flags |= AS_AREA_WRITE;
219
if (entry->p_flags & PF_R)
220
flags |= AS_AREA_READ;
221
flags |= AS_AREA_CACHEABLE;
224
* Align vaddr down, inserting a little "gap" at the beginning.
225
* Adjust area size, so that its end remains in place.
227
base = ALIGN_DOWN(entry->p_vaddr, PAGE_SIZE);
228
mem_sz = entry->p_memsz + (entry->p_vaddr - base);
230
a = as_area_create(as, flags, mem_sz, base,
231
AS_AREA_ATTR_NONE, &elf_backend, &backend_data);
236
* The segment will be mapped on demand by elf_page_fault().
242
/** Process section header.
244
* @param entry Segment header.
245
* @param elf ELF header.
246
* @param as Address space into wich the ELF is being loaded.
248
* @return EE_OK on success, error code otherwise.
250
static int section_header(elf_section_header_t *entry, elf_header_t *elf,
253
switch (entry->sh_type) {
255
if (entry->sh_flags & SHF_TLS) {
260
if (entry->sh_flags & SHF_TLS) {