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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,
3222 svoboda 60
    as_t *as, int flags);
2574 jermar 61
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
3222 svoboda 70
 * @param flags A combination of ELD_F_*
854 bondari 71
 * @return EE_OK on success
72
 */
3222 svoboda 73
unsigned int elf_load(elf_header_t *header, as_t * as, int flags)
938 jermar 74
{
75
    int i, rc;
910 bondari 76
 
77
    /* Identify ELF */
2574 jermar 78
    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 82
        return EE_INVALID;
83
    }
84
 
85
    /* Identify ELF compatibility */
2574 jermar 86
    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 ||
89
        header->e_version != EV_CURRENT ||
938 jermar 90
        header->e_ident[EI_CLASS] != ELF_CLASS) {
91
        return EE_INCOMPATIBLE;
92
    }
93
 
952 jermar 94
    if (header->e_phentsize != sizeof(elf_segment_header_t))
938 jermar 95
        return EE_INCOMPATIBLE;
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952 jermar 97
    if (header->e_shentsize != sizeof(elf_section_header_t))
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        return EE_INCOMPATIBLE;
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938 jermar 100
    /* Check if the object type is supported. */
101
    if (header->e_type != ET_EXEC)
910 bondari 102
        return EE_UNSUPPORTED;
938 jermar 103
 
3007 jermar 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;
107
 
952 jermar 108
    /* Walk through all segment headers and process them. */
938 jermar 109
    for (i = 0; i < header->e_phnum; i++) {
2574 jermar 110
        elf_segment_header_t *seghdr;
111
 
112
        seghdr = &((elf_segment_header_t *)(((uint8_t *) header) +
113
            header->e_phoff))[i];
3222 svoboda 114
        rc = segment_header(seghdr, header, as, flags);
938 jermar 115
        if (rc != EE_OK)
116
            return rc;
910 bondari 117
    }
938 jermar 118
 
952 jermar 119
    /* Inspect all section headers and proccess them. */
120
    for (i = 0; i < header->e_shnum; i++) {
2574 jermar 121
        elf_section_header_t *sechdr;
122
 
123
        sechdr = &((elf_section_header_t *)(((uint8_t *) header) +
124
            header->e_shoff))[i];
125
        rc = section_header(sechdr, header, as);
952 jermar 126
        if (rc != EE_OK)
127
            return rc;
128
    }
129
 
938 jermar 130
    return EE_OK;
131
}
132
 
133
/** Print error message according to error code.
134
 *
135
 * @param rc Return code returned by elf_load().
136
 *
137
 * @return NULL terminated description of error.
138
 */
2745 decky 139
char *elf_error(unsigned int rc)
938 jermar 140
{
2574 jermar 141
    ASSERT(rc < sizeof(error_codes) / sizeof(char *));
938 jermar 142
 
143
    return error_codes[rc];
144
}
145
 
952 jermar 146
/** Process segment header.
938 jermar 147
 *
952 jermar 148
 * @param entry Segment header.
149
 * @param elf ELF header.
938 jermar 150
 * @param as Address space into wich the ELF is being loaded.
151
 *
152
 * @return EE_OK on success, error code otherwise.
153
 */
2574 jermar 154
static int segment_header(elf_segment_header_t *entry, elf_header_t *elf,
3222 svoboda 155
    as_t *as, int flags)
938 jermar 156
{
3222 svoboda 157
    char *interp;
158
 
938 jermar 159
    switch (entry->p_type) {
2062 jermar 160
    case PT_NULL:
161
    case PT_PHDR:
938 jermar 162
        break;
2062 jermar 163
    case PT_LOAD:
952 jermar 164
        return load_segment(entry, elf, as);
938 jermar 165
        break;
2062 jermar 166
    case PT_DYNAMIC:
167
    case PT_INTERP:
3222 svoboda 168
        interp = (char *)elf + entry->p_offset;
169
        /* FIXME */
170
        /*if (memcmp((uintptr_t)interp, (uintptr_t)ELF_INTERP_ZSTR,
171
            ELF_INTERP_ZLEN) != 0) {
172
            return EE_UNSUPPORTED;
173
        }*/
174
        if ((flags & ELD_F_LOADER) == 0) {
175
            return EE_LOADER;
176
        }
177
        break;
2062 jermar 178
    case PT_SHLIB:
179
    case PT_NOTE:
180
    case PT_LOPROC:
181
    case PT_HIPROC:
182
    default:
938 jermar 183
        return EE_UNSUPPORTED;
184
        break;
185
    }
186
    return EE_OK;
187
}
188
 
189
/** Load segment described by program header entry.
190
 *
191
 * @param entry Program header entry describing segment to be loaded.
952 jermar 192
 * @param elf ELF header.
1248 jermar 193
 * @param as Address space into wich the ELF is being loaded.
938 jermar 194
 *
195
 * @return EE_OK on success, error code otherwise.
196
 */
952 jermar 197
int load_segment(elf_segment_header_t *entry, elf_header_t *elf, as_t *as)
938 jermar 198
{
199
    as_area_t *a;
1409 jermar 200
    int flags = 0;
1425 jermar 201
    mem_backend_data_t backend_data;
3007 jermar 202
    uintptr_t base;
203
    size_t mem_sz;
1425 jermar 204
 
205
    backend_data.elf = elf;
206
    backend_data.segment = entry;
938 jermar 207
 
208
    if (entry->p_align > 1) {
2574 jermar 209
        if ((entry->p_offset % entry->p_align) !=
210
            (entry->p_vaddr % entry->p_align)) {
938 jermar 211
            return EE_INVALID;
212
        }
213
    }
214
 
1026 jermar 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;
1424 jermar 221
    flags |= AS_AREA_CACHEABLE;
910 bondari 222
 
3007 jermar 223
    /*
224
     * Align vaddr down, inserting a little "gap" at the beginning.
225
     * Adjust area size, so that its end remains in place.
952 jermar 226
     */
3007 jermar 227
    base = ALIGN_DOWN(entry->p_vaddr, PAGE_SIZE);
228
    mem_sz = entry->p_memsz + (entry->p_vaddr - base);
952 jermar 229
 
3007 jermar 230
    a = as_area_create(as, flags, mem_sz, base,
2574 jermar 231
        AS_AREA_ATTR_NONE, &elf_backend, &backend_data);
938 jermar 232
    if (!a)
1070 jermar 233
        return EE_MEMORY;
938 jermar 234
 
1409 jermar 235
    /*
236
     * The segment will be mapped on demand by elf_page_fault().
237
     */
238
 
938 jermar 239
    return EE_OK;
854 bondari 240
}
952 jermar 241
 
242
/** Process section header.
243
 *
244
 * @param entry Segment header.
245
 * @param elf ELF header.
246
 * @param as Address space into wich the ELF is being loaded.
247
 *
248
 * @return EE_OK on success, error code otherwise.
249
 */
2574 jermar 250
static int section_header(elf_section_header_t *entry, elf_header_t *elf,
251
    as_t *as)
952 jermar 252
{
253
    switch (entry->sh_type) {
2574 jermar 254
    case SHT_PROGBITS:
255
        if (entry->sh_flags & SHF_TLS) {
256
            /* .tdata */
257
        }
258
        break;
259
    case SHT_NOBITS:
260
        if (entry->sh_flags & SHF_TLS) {
261
            /* .tbss */
262
        }
263
        break;
2062 jermar 264
    default:
952 jermar 265
        break;
266
    }
267
 
268
    return EE_OK;
269
}
1702 cejka 270
 
1757 jermar 271
/** @}
1702 cejka 272
 */