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854 bondari 1
/*
2071 jermar 2
 * Copyright (c) 2006 Sergey Bondari
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 * Copyright (c) 2006 Jakub Jermar
854 bondari 4
 * All rights reserved.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * are met:
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 *
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 * - Redistributions of source code must retain the above copyright
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 *   notice, this list of conditions and the following disclaimer.
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 * - Redistributions in binary form must reproduce the above copyright
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 *   notice, this list of conditions and the following disclaimer in the
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 *   documentation and/or other materials provided with the distribution.
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 * - The name of the author may not be used to endorse or promote products
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 *   derived from this software without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 */
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1757 jermar 30
/** @addtogroup generic
1702 cejka 31
 * @{
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 */
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1264 jermar 34
/**
1702 cejka 35
 * @file
1264 jermar 36
 * @brief   Kernel ELF loader.
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 */
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2000 decky 39
#include <lib/elf.h>
938 jermar 40
#include <debug.h>
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#include <arch/types.h>
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#include <mm/as.h>
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#include <mm/frame.h>
952 jermar 44
#include <mm/slab.h>
938 jermar 45
#include <align.h>
952 jermar 46
#include <memstr.h>
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#include <macros.h>
1409 jermar 48
#include <arch.h>
854 bondari 49
 
938 jermar 50
static char *error_codes[] = {
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    "no error",
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    "invalid image",
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    "address space error",
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    "incompatible image",
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    "unsupported image type",
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    "irrecoverable error"
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};
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952 jermar 59
static int segment_header(elf_segment_header_t *entry, elf_header_t *elf, as_t *as);
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static int section_header(elf_section_header_t *entry, elf_header_t *elf, as_t *as);
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static int load_segment(elf_segment_header_t *entry, elf_header_t *elf, as_t *as);
938 jermar 62
 
63
/** ELF loader
854 bondari 64
 *
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 * @param header Pointer to ELF header in memory
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 * @param as Created and properly mapped address space
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 * @return EE_OK on success
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 */
938 jermar 69
int elf_load(elf_header_t *header, as_t * as)
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{
71
    int i, rc;
910 bondari 72
 
73
    /* Identify ELF */
938 jermar 74
    if (header->e_ident[EI_MAG0] != ELFMAG0 || header->e_ident[EI_MAG1] != ELFMAG1 ||
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        header->e_ident[EI_MAG2] != ELFMAG2 || header->e_ident[EI_MAG3] != ELFMAG3) {
910 bondari 76
        return EE_INVALID;
77
    }
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79
    /* Identify ELF compatibility */
938 jermar 80
    if (header->e_ident[EI_DATA] != ELF_DATA_ENCODING || header->e_machine != ELF_MACHINE ||
81
        header->e_ident[EI_VERSION] != EV_CURRENT || header->e_version != EV_CURRENT ||
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        header->e_ident[EI_CLASS] != ELF_CLASS) {
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        return EE_INCOMPATIBLE;
84
    }
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952 jermar 86
    if (header->e_phentsize != sizeof(elf_segment_header_t))
938 jermar 87
        return EE_INCOMPATIBLE;
88
 
952 jermar 89
    if (header->e_shentsize != sizeof(elf_section_header_t))
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        return EE_INCOMPATIBLE;
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938 jermar 92
    /* Check if the object type is supported. */
93
    if (header->e_type != ET_EXEC)
910 bondari 94
        return EE_UNSUPPORTED;
938 jermar 95
 
952 jermar 96
    /* Walk through all segment headers and process them. */
938 jermar 97
    for (i = 0; i < header->e_phnum; i++) {
1780 jermar 98
        rc = segment_header(&((elf_segment_header_t *)(((uint8_t *) header) + header->e_phoff))[i], header, as);
938 jermar 99
        if (rc != EE_OK)
100
            return rc;
910 bondari 101
    }
938 jermar 102
 
952 jermar 103
    /* Inspect all section headers and proccess them. */
104
    for (i = 0; i < header->e_shnum; i++) {
1780 jermar 105
        rc = section_header(&((elf_section_header_t *)(((uint8_t *) header) + header->e_shoff))[i], header, as);
952 jermar 106
        if (rc != EE_OK)
107
            return rc;
108
    }
109
 
938 jermar 110
    return EE_OK;
111
}
112
 
113
/** Print error message according to error code.
114
 *
115
 * @param rc Return code returned by elf_load().
116
 *
117
 * @return NULL terminated description of error.
118
 */
119
char *elf_error(int rc)
120
{
121
    ASSERT(rc < sizeof(error_codes)/sizeof(char *));
122
 
123
    return error_codes[rc];
124
}
125
 
952 jermar 126
/** Process segment header.
938 jermar 127
 *
952 jermar 128
 * @param entry Segment header.
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 * @param elf ELF header.
938 jermar 130
 * @param as Address space into wich the ELF is being loaded.
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 *
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 * @return EE_OK on success, error code otherwise.
133
 */
952 jermar 134
static int segment_header(elf_segment_header_t *entry, elf_header_t *elf, as_t *as)
938 jermar 135
{
136
    switch (entry->p_type) {
2062 jermar 137
    case PT_NULL:
138
    case PT_PHDR:
938 jermar 139
        break;
2062 jermar 140
    case PT_LOAD:
952 jermar 141
        return load_segment(entry, elf, as);
938 jermar 142
        break;
2062 jermar 143
    case PT_DYNAMIC:
144
    case PT_INTERP:
145
    case PT_SHLIB:
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    case PT_NOTE:
147
    case PT_LOPROC:
148
    case PT_HIPROC:
149
    default:
938 jermar 150
        return EE_UNSUPPORTED;
151
        break;
152
    }
153
    return EE_OK;
154
}
155
 
156
/** Load segment described by program header entry.
157
 *
158
 * @param entry Program header entry describing segment to be loaded.
952 jermar 159
 * @param elf ELF header.
1248 jermar 160
 * @param as Address space into wich the ELF is being loaded.
938 jermar 161
 *
162
 * @return EE_OK on success, error code otherwise.
163
 */
952 jermar 164
int load_segment(elf_segment_header_t *entry, elf_header_t *elf, as_t *as)
938 jermar 165
{
166
    as_area_t *a;
1409 jermar 167
    int flags = 0;
1425 jermar 168
    mem_backend_data_t backend_data;
169
 
170
    backend_data.elf = elf;
171
    backend_data.segment = entry;
938 jermar 172
 
173
    if (entry->p_align > 1) {
174
        if ((entry->p_offset % entry->p_align) != (entry->p_vaddr % entry->p_align)) {
175
            return EE_INVALID;
176
        }
177
    }
178
 
1026 jermar 179
    if (entry->p_flags & PF_X)
180
        flags |= AS_AREA_EXEC;
181
    if (entry->p_flags & PF_W)
182
        flags |= AS_AREA_WRITE;
183
    if (entry->p_flags & PF_R)
184
        flags |= AS_AREA_READ;
1424 jermar 185
    flags |= AS_AREA_CACHEABLE;
910 bondari 186
 
952 jermar 187
    /*
188
     * Check if the virtual address starts on page boundary.
189
     */
190
    if (ALIGN_UP(entry->p_vaddr, PAGE_SIZE) != entry->p_vaddr)
191
        return EE_UNSUPPORTED;
192
 
1424 jermar 193
    a = as_area_create(as, flags, entry->p_memsz, entry->p_vaddr, AS_AREA_ATTR_NONE,
194
        &elf_backend, &backend_data);
938 jermar 195
    if (!a)
1070 jermar 196
        return EE_MEMORY;
938 jermar 197
 
1409 jermar 198
    /*
199
     * The segment will be mapped on demand by elf_page_fault().
200
     */
201
 
938 jermar 202
    return EE_OK;
854 bondari 203
}
952 jermar 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
 */
213
static int section_header(elf_section_header_t *entry, elf_header_t *elf, as_t *as)
214
{
215
    switch (entry->sh_type) {
2062 jermar 216
    default:
952 jermar 217
        break;
218
    }
219
 
220
    return EE_OK;
221
}
1702 cejka 222
 
1757 jermar 223
/** @}
1702 cejka 224
 */