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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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2574 jermar 59
static int segment_header(elf_segment_header_t *entry, elf_header_t *elf,
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    as_t *as);
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static int section_header(elf_section_header_t *entry, elf_header_t *elf,
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    as_t *as);
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static int load_segment(elf_segment_header_t *entry, elf_header_t *elf,
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    as_t *as);
938 jermar 65
 
66
/** ELF loader
854 bondari 67
 *
68
 * @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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 */
2745 decky 72
unsigned int elf_load(elf_header_t *header, as_t * as)
938 jermar 73
{
74
    int i, rc;
910 bondari 75
 
76
    /* Identify ELF */
2574 jermar 77
    if (header->e_ident[EI_MAG0] != ELFMAG0 ||
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        header->e_ident[EI_MAG1] != ELFMAG1 ||
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        header->e_ident[EI_MAG2] != ELFMAG2 ||
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        header->e_ident[EI_MAG3] != ELFMAG3) {
910 bondari 81
        return EE_INVALID;
82
    }
83
 
84
    /* Identify ELF compatibility */
2574 jermar 85
    if (header->e_ident[EI_DATA] != ELF_DATA_ENCODING ||
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        header->e_machine != ELF_MACHINE ||
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        header->e_ident[EI_VERSION] != EV_CURRENT ||
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        header->e_version != EV_CURRENT ||
938 jermar 89
        header->e_ident[EI_CLASS] != ELF_CLASS) {
90
        return EE_INCOMPATIBLE;
91
    }
92
 
952 jermar 93
    if (header->e_phentsize != sizeof(elf_segment_header_t))
938 jermar 94
        return EE_INCOMPATIBLE;
95
 
952 jermar 96
    if (header->e_shentsize != sizeof(elf_section_header_t))
97
        return EE_INCOMPATIBLE;
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938 jermar 99
    /* Check if the object type is supported. */
100
    if (header->e_type != ET_EXEC)
910 bondari 101
        return EE_UNSUPPORTED;
938 jermar 102
 
3011 svoboda 103
    /* Check if the ELF image starts on a page boundary */
104
    if (ALIGN_UP((uintptr_t)header, PAGE_SIZE) != (uintptr_t)header)
105
        return EE_UNSUPPORTED;
106
 
952 jermar 107
    /* Walk through all segment headers and process them. */
938 jermar 108
    for (i = 0; i < header->e_phnum; i++) {
2574 jermar 109
        elf_segment_header_t *seghdr;
110
 
111
        seghdr = &((elf_segment_header_t *)(((uint8_t *) header) +
112
            header->e_phoff))[i];
113
        rc = segment_header(seghdr, header, as);
938 jermar 114
        if (rc != EE_OK)
115
            return rc;
910 bondari 116
    }
938 jermar 117
 
952 jermar 118
    /* Inspect all section headers and proccess them. */
119
    for (i = 0; i < header->e_shnum; i++) {
2574 jermar 120
        elf_section_header_t *sechdr;
121
 
122
        sechdr = &((elf_section_header_t *)(((uint8_t *) header) +
123
            header->e_shoff))[i];
124
        rc = section_header(sechdr, header, as);
952 jermar 125
        if (rc != EE_OK)
126
            return rc;
127
    }
128
 
938 jermar 129
    return EE_OK;
130
}
131
 
132
/** Print error message according to error code.
133
 *
134
 * @param rc Return code returned by elf_load().
135
 *
136
 * @return NULL terminated description of error.
137
 */
2745 decky 138
char *elf_error(unsigned int rc)
938 jermar 139
{
2574 jermar 140
    ASSERT(rc < sizeof(error_codes) / sizeof(char *));
938 jermar 141
 
142
    return error_codes[rc];
143
}
144
 
952 jermar 145
/** Process segment header.
938 jermar 146
 *
952 jermar 147
 * @param entry Segment header.
148
 * @param elf ELF header.
938 jermar 149
 * @param as Address space into wich the ELF is being loaded.
150
 *
151
 * @return EE_OK on success, error code otherwise.
152
 */
2574 jermar 153
static int segment_header(elf_segment_header_t *entry, elf_header_t *elf,
154
    as_t *as)
938 jermar 155
{
156
    switch (entry->p_type) {
2062 jermar 157
    case PT_NULL:
158
    case PT_PHDR:
938 jermar 159
        break;
2062 jermar 160
    case PT_LOAD:
952 jermar 161
        return load_segment(entry, elf, as);
938 jermar 162
        break;
2062 jermar 163
    case PT_DYNAMIC:
164
    case PT_INTERP:
165
    case PT_SHLIB:
166
    case PT_NOTE:
167
    case PT_LOPROC:
168
    case PT_HIPROC:
169
    default:
938 jermar 170
        return EE_UNSUPPORTED;
171
        break;
172
    }
173
    return EE_OK;
174
}
175
 
176
/** Load segment described by program header entry.
177
 *
178
 * @param entry Program header entry describing segment to be loaded.
952 jermar 179
 * @param elf ELF header.
1248 jermar 180
 * @param as Address space into wich the ELF is being loaded.
938 jermar 181
 *
182
 * @return EE_OK on success, error code otherwise.
183
 */
952 jermar 184
int load_segment(elf_segment_header_t *entry, elf_header_t *elf, as_t *as)
938 jermar 185
{
186
    as_area_t *a;
1409 jermar 187
    int flags = 0;
1425 jermar 188
    mem_backend_data_t backend_data;
3011 svoboda 189
    uintptr_t base;
190
    size_t mem_sz;
1425 jermar 191
 
192
    backend_data.elf = elf;
193
    backend_data.segment = entry;
938 jermar 194
 
195
    if (entry->p_align > 1) {
2574 jermar 196
        if ((entry->p_offset % entry->p_align) !=
197
            (entry->p_vaddr % entry->p_align)) {
938 jermar 198
            return EE_INVALID;
199
        }
200
    }
201
 
1026 jermar 202
    if (entry->p_flags & PF_X)
203
        flags |= AS_AREA_EXEC;
204
    if (entry->p_flags & PF_W)
205
        flags |= AS_AREA_WRITE;
206
    if (entry->p_flags & PF_R)
207
        flags |= AS_AREA_READ;
1424 jermar 208
    flags |= AS_AREA_CACHEABLE;
910 bondari 209
 
3011 svoboda 210
    /*
211
     * Align vaddr down, inserting a little "gap" at the beginning.
212
     * Adjust area size, so that its end remains in place.
952 jermar 213
     */
3011 svoboda 214
    base = ALIGN_DOWN(entry->p_vaddr, PAGE_SIZE);
215
    mem_sz = entry->p_memsz + (entry->p_vaddr - base);
952 jermar 216
 
3011 svoboda 217
    a = as_area_create(as, flags, mem_sz, base,
2574 jermar 218
        AS_AREA_ATTR_NONE, &elf_backend, &backend_data);
938 jermar 219
    if (!a)
1070 jermar 220
        return EE_MEMORY;
938 jermar 221
 
1409 jermar 222
    /*
223
     * The segment will be mapped on demand by elf_page_fault().
224
     */
225
 
938 jermar 226
    return EE_OK;
854 bondari 227
}
952 jermar 228
 
229
/** Process section header.
230
 *
231
 * @param entry Segment header.
232
 * @param elf ELF header.
233
 * @param as Address space into wich the ELF is being loaded.
234
 *
235
 * @return EE_OK on success, error code otherwise.
236
 */
2574 jermar 237
static int section_header(elf_section_header_t *entry, elf_header_t *elf,
238
    as_t *as)
952 jermar 239
{
240
    switch (entry->sh_type) {
2574 jermar 241
    case SHT_PROGBITS:
242
        if (entry->sh_flags & SHF_TLS) {
243
            /* .tdata */
244
        }
245
        break;
246
    case SHT_NOBITS:
247
        if (entry->sh_flags & SHF_TLS) {
248
            /* .tbss */
249
        }
250
        break;
2062 jermar 251
    default:
952 jermar 252
        break;
253
    }
254
 
255
    return EE_OK;
256
}
1702 cejka 257
 
1757 jermar 258
/** @}
1702 cejka 259
 */