[292] | 1 | /** |
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[586] | 2 | * \file : reset_elf_loader.c |
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[292] | 3 | * \date : August 2012 |
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| 4 | * \author : Cesar Fuguet |
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| 5 | * |
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[586] | 6 | * This file defines an elf file loader which reads an executable .elf file |
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| 7 | * starting at a sector passed as argument on a disk and copy the different |
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[292] | 8 | * ELF program segments in the appropriate memory address using as information |
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[586] | 9 | * the virtual address read from the .elf file. |
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[292] | 10 | */ |
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| 11 | |
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[586] | 12 | #include <reset_ioc.h> |
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[292] | 13 | #include <elf-types.h> |
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[586] | 14 | #include <reset_tty.h> |
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| 15 | #include <reset_utils.h> |
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[292] | 16 | #include <defs.h> |
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| 17 | |
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[586] | 18 | #if (RESET_DEBUG == 1) |
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| 19 | static char const * const init_state_str[] = |
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| 20 | { |
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[425] | 21 | "ELF_HEADER_STATE", |
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| 22 | "ELF_PROGRAM_HEADER_STATE", |
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| 23 | "ELF_OFFSET_STATE", |
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| 24 | "ELF_SEGMENT_STATE", |
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| 25 | "ELF_END_STATE" |
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| 26 | }; |
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| 27 | #endif |
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| 28 | |
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[586] | 29 | unsigned char reset_elf_loader_buffer[512] __attribute__((aligned(CACHE_LINE_SIZE))); |
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[570] | 30 | |
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[586] | 31 | ///////////////////////////////////////////////////////////////////////////////////// |
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| 32 | void * reset_elf_loader(unsigned int lba) |
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| 33 | ///////////////////////////////////////////////////////////////////////////////////// |
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[292] | 34 | { |
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[425] | 35 | /* |
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[586] | 36 | * Temporary variables used by the loader |
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[292] | 37 | */ |
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| 38 | Elf32_Ehdr elf_header; |
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| 39 | Elf32_Phdr elf_pht[PHDR_ARRAY_SIZE]; |
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| 40 | |
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| 41 | unsigned char * buffer_ptr; |
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[425] | 42 | Elf32_Ehdr * elf_ehdr_ptr; |
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| 43 | Elf32_Phdr * elf_phdr_ptr; |
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[292] | 44 | |
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| 45 | unsigned int nb_available; |
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| 46 | unsigned int nb_rest; |
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| 47 | unsigned int nb_read; |
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| 48 | unsigned int nb_block; |
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| 49 | unsigned int offset; |
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[425] | 50 | |
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| 51 | unsigned char * pseg_ptr; |
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| 52 | unsigned int pseg_start; |
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| 53 | unsigned int pseg_end; |
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| 54 | unsigned int pseg_remainder; |
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[292] | 55 | unsigned int pseg; |
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[412] | 56 | |
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[292] | 57 | /* |
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| 58 | * Loader state machine definition |
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[412] | 59 | */ |
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[425] | 60 | typedef enum |
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[292] | 61 | { |
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| 62 | ELF_HEADER_STATE, |
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| 63 | ELF_PROGRAM_HEADER_STATE, |
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| 64 | ELF_OFFSET_STATE, |
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| 65 | ELF_SEGMENT_STATE, |
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| 66 | ELF_END_STATE |
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[425] | 67 | } elf_loader_t; |
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[292] | 68 | |
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[425] | 69 | elf_loader_t init_state; |
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| 70 | init_state = ELF_HEADER_STATE; |
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| 71 | |
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[586] | 72 | #if (RESET_DEBUG == 1) |
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[425] | 73 | elf_loader_t init_state_debug; |
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| 74 | init_state_debug = ELF_END_STATE; |
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[412] | 75 | #endif |
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| 76 | |
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[586] | 77 | reset_puts("\n[RESET] Start reset_elf_loader at cycle "); |
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| 78 | reset_putd( proctime() ); |
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| 79 | reset_puts("\n"); |
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[292] | 80 | |
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[425] | 81 | nb_block = lba; |
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| 82 | nb_available = 0; |
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| 83 | nb_rest = sizeof(Elf32_Ehdr); |
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| 84 | pseg = 0; |
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| 85 | offset = 0; |
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| 86 | elf_ehdr_ptr = (Elf32_Ehdr *) &elf_header; |
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| 87 | elf_phdr_ptr = (Elf32_Phdr *) &elf_pht[0]; |
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[292] | 88 | |
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| 89 | while(init_state != ELF_END_STATE) |
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| 90 | { |
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[425] | 91 | if (nb_available == 0 ) |
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[292] | 92 | { |
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[586] | 93 | buffer_ptr = &reset_elf_loader_buffer[0]; |
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[292] | 94 | |
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[586] | 95 | if (reset_ioc_read(nb_block , buffer_ptr, 1)) |
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[292] | 96 | { |
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[586] | 97 | reset_puts ("[RESET ERROR] reset_ioc_read() failed\n"); |
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| 98 | reset_exit(); |
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[292] | 99 | } |
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[388] | 100 | |
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[292] | 101 | nb_block += 1; |
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| 102 | nb_available = 512; |
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| 103 | } |
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| 104 | |
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| 105 | nb_read = (nb_rest <= nb_available) ? nb_rest : nb_available; |
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| 106 | offset += nb_read; |
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| 107 | |
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[586] | 108 | #if (RESET_DEBUG == 1) |
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[412] | 109 | if (init_state != init_state_debug) |
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| 110 | { |
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[586] | 111 | reset_puts("\ninit_state = "); |
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| 112 | reset_puts(init_state_str[init_state]); |
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| 113 | reset_puts("\n"); |
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[412] | 114 | init_state_debug = init_state; |
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| 115 | } |
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| 116 | #endif |
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| 117 | |
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[292] | 118 | switch(init_state) |
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| 119 | { |
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[425] | 120 | /* |
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[292] | 121 | * Reading ELF executable header |
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| 122 | */ |
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| 123 | case ELF_HEADER_STATE: |
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[425] | 124 | memcpy(elf_ehdr_ptr, buffer_ptr, nb_read); |
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[292] | 125 | |
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| 126 | nb_rest -= nb_read; |
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| 127 | |
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| 128 | if(nb_rest == 0) |
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| 129 | { |
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[425] | 130 | nb_rest = elf_ehdr_ptr->e_phnum * elf_ehdr_ptr->e_phentsize; |
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| 131 | /* |
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| 132 | * Verification of ELF Magic Number |
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| 133 | */ |
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| 134 | if ( (elf_ehdr_ptr->e_ident[EI_MAG0] != ELFMAG0) || |
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| 135 | (elf_ehdr_ptr->e_ident[EI_MAG1] != ELFMAG1) || |
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| 136 | (elf_ehdr_ptr->e_ident[EI_MAG2] != ELFMAG2) || |
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| 137 | (elf_ehdr_ptr->e_ident[EI_MAG3] != ELFMAG3) ) |
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[388] | 138 | { |
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[586] | 139 | reset_puts("[RESET ERROR] boot-loader file is not an ELF format\n"); |
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| 140 | reset_exit(); |
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[388] | 141 | } |
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[292] | 142 | |
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[412] | 143 | /* |
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[388] | 144 | * Verification of Program Headers table size. It must be |
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[412] | 145 | * smaller than the work size allocated for the |
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[388] | 146 | * elf_pht[PHDR_ARRAY_SIZE] array |
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[425] | 147 | */ |
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| 148 | if (elf_ehdr_ptr->e_phnum > PHDR_ARRAY_SIZE) |
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[292] | 149 | { |
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[586] | 150 | reset_puts("[RESET ERROR] ELF PHDR table size too large\n"); |
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| 151 | reset_exit(); |
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[292] | 152 | } |
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| 153 | |
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| 154 | init_state = ELF_PROGRAM_HEADER_STATE; |
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| 155 | } |
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| 156 | |
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| 157 | break; |
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| 158 | |
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[425] | 159 | /* |
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[292] | 160 | * Reading ELF program headers |
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[412] | 161 | */ |
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[292] | 162 | case ELF_PROGRAM_HEADER_STATE: |
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[425] | 163 | memcpy(elf_phdr_ptr, buffer_ptr, nb_read); |
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[292] | 164 | |
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[425] | 165 | elf_phdr_ptr = |
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| 166 | (Elf32_Phdr *)((unsigned char *) elf_phdr_ptr + nb_read); |
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[292] | 167 | |
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[425] | 168 | nb_rest -= nb_read; |
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| 169 | |
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[292] | 170 | if(nb_rest == 0) |
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| 171 | { |
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[425] | 172 | elf_phdr_ptr = (Elf32_Phdr *) &elf_pht[0]; |
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[292] | 173 | |
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| 174 | /* |
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| 175 | * Search the first not NULL segment in the ELF file |
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| 176 | */ |
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[425] | 177 | for (pseg = 0; pseg < elf_ehdr_ptr->e_phnum; pseg++) |
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[292] | 178 | { |
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[425] | 179 | if(elf_phdr_ptr[pseg].p_type == PT_LOAD) |
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[292] | 180 | { |
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[586] | 181 | #if (RESET_DEBUG == 1) |
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| 182 | reset_puts("loadable segment found:\n"); |
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| 183 | reset_print_elf_phdr(&elf_phdr_ptr[pseg]); |
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[412] | 184 | #endif |
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[425] | 185 | if (elf_phdr_ptr[pseg].p_offset < offset) |
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[412] | 186 | { |
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[415] | 187 | /* |
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[425] | 188 | * Case where the segment to load includes the |
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| 189 | * elf and program headers |
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| 190 | */ |
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| 191 | nb_rest = elf_phdr_ptr[pseg].p_filesz - offset; |
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[412] | 192 | init_state = ELF_SEGMENT_STATE; |
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| 193 | } |
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| 194 | else |
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| 195 | { |
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[415] | 196 | /* |
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| 197 | * Segment to load is further away in ELF file |
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[425] | 198 | */ |
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| 199 | nb_rest = elf_phdr_ptr[pseg].p_offset - offset; |
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[412] | 200 | init_state = ELF_OFFSET_STATE; |
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| 201 | } |
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[292] | 202 | break; |
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| 203 | } |
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| 204 | } |
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| 205 | |
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[425] | 206 | if (pseg == elf_ehdr_ptr->e_phnum) |
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[412] | 207 | { |
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[586] | 208 | reset_puts("[RESET ERROR] No PT_LOAD found\n"); |
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| 209 | reset_exit(); |
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[412] | 210 | } |
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| 211 | |
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[292] | 212 | } |
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| 213 | |
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| 214 | break; |
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| 215 | |
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[425] | 216 | /* |
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[415] | 217 | * Go to the offset of the first not null program segment in the |
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| 218 | * ELF file |
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[425] | 219 | * |
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| 220 | * TODO: |
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| 221 | * No need to read from the disk the useless bytes. Try to compute |
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| 222 | * the next usefull lba |
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[292] | 223 | */ |
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| 224 | case ELF_OFFSET_STATE: |
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| 225 | nb_rest -= nb_read; |
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| 226 | |
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| 227 | if (nb_rest == 0) |
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| 228 | { |
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[425] | 229 | nb_rest = elf_phdr_ptr[pseg].p_filesz; |
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[292] | 230 | init_state = ELF_SEGMENT_STATE; |
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| 231 | } |
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| 232 | |
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| 233 | break; |
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| 234 | |
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[425] | 235 | /* |
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[292] | 236 | * Reading ELF segments |
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[425] | 237 | * |
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| 238 | * TODO: |
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| 239 | * Do not pass by block buffer but write directly in target memory |
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| 240 | * address |
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[292] | 241 | */ |
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| 242 | case ELF_SEGMENT_STATE: |
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[425] | 243 | /* |
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| 244 | * Verify that loadable segment does not conflict with |
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| 245 | * pre-loader memory space |
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[412] | 246 | */ |
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[425] | 247 | pseg_start = elf_phdr_ptr[pseg].p_vaddr; |
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[292] | 248 | |
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[425] | 249 | pseg_end = elf_phdr_ptr[pseg].p_vaddr + |
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| 250 | elf_phdr_ptr[pseg].p_memsz; |
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| 251 | |
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| 252 | if ((pseg_start >= 0xBFC00000 && pseg_start <= 0xBFC10000) || |
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| 253 | (pseg_end >= 0xBFC00000 && pseg_end <= 0xBFC10000) || |
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| 254 | (pseg_start < 0xBFC00000 && pseg_end > 0xBFC10000)) |
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[292] | 255 | { |
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[586] | 256 | reset_puts("[RESET ERROR] conflict with pre-loader memory space\n"); |
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| 257 | reset_exit(); |
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[292] | 258 | } |
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[412] | 259 | |
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[425] | 260 | /* |
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| 261 | * Copy the ELF segment data in memory using the |
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| 262 | * virtual address obtained from the ELF file |
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| 263 | */ |
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| 264 | pseg_ptr = (unsigned char *) |
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| 265 | elf_phdr_ptr[pseg].p_vaddr + |
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| 266 | elf_phdr_ptr[pseg].p_filesz - |
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| 267 | nb_rest; |
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| 268 | |
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| 269 | memcpy(pseg_ptr, buffer_ptr, nb_read); |
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| 270 | |
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[292] | 271 | nb_rest -= nb_read; |
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| 272 | |
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[425] | 273 | if (nb_rest == 0) |
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[292] | 274 | { |
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[425] | 275 | /* |
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| 276 | * Fill remaining bytes with zeros (filesz < memsz) |
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| 277 | */ |
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| 278 | pseg_remainder = |
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| 279 | elf_phdr_ptr[pseg].p_memsz - |
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| 280 | elf_phdr_ptr[pseg].p_filesz ; |
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[292] | 281 | |
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[425] | 282 | pseg_ptr = (unsigned char *) |
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| 283 | elf_phdr_ptr[pseg].p_vaddr + |
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| 284 | elf_phdr_ptr[pseg].p_filesz ; |
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[292] | 285 | |
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[591] | 286 | memset(pseg_ptr, 0, pseg_remainder); |
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[425] | 287 | |
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[586] | 288 | reset_puts("\n[RESET] Segment loaded : address = "); |
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| 289 | reset_putx(elf_phdr_ptr[pseg].p_vaddr); |
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| 290 | reset_puts(" / size = "); |
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| 291 | reset_putx(elf_phdr_ptr[pseg].p_filesz); |
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| 292 | reset_puts("\n"); |
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[425] | 293 | |
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[292] | 294 | /* |
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[425] | 295 | * Search the next first not NULL segment in the ELF file |
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[292] | 296 | */ |
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[425] | 297 | for (pseg += 1; pseg < elf_ehdr_ptr->e_phnum; pseg++) |
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| 298 | { |
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| 299 | if(elf_phdr_ptr[pseg].p_type == PT_LOAD) |
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[292] | 300 | { |
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[586] | 301 | #if (RESET_DEBUG == 1) |
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| 302 | reset_puts("loadable segment found:\n"); |
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| 303 | reset_print_elf_phdr(&elf_phdr_ptr[pseg]); |
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[425] | 304 | #endif |
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| 305 | nb_rest = elf_phdr_ptr[pseg].p_offset - offset; |
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[292] | 306 | break; |
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| 307 | } |
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| 308 | } |
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| 309 | |
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| 310 | /* |
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| 311 | * Program loading finished |
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[412] | 312 | */ |
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[425] | 313 | if(pseg == elf_ehdr_ptr->e_phnum) |
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[292] | 314 | { |
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| 315 | init_state = ELF_END_STATE; |
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| 316 | break; |
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| 317 | } |
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| 318 | |
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| 319 | init_state = ELF_OFFSET_STATE; |
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| 320 | } |
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| 321 | break; |
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| 322 | |
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| 323 | default: |
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| 324 | break; |
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| 325 | } |
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| 326 | |
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[425] | 327 | buffer_ptr += nb_read; |
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| 328 | nb_available -= nb_read; |
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[292] | 329 | } |
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| 330 | |
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[586] | 331 | reset_puts("\n[RESET] Complete reset_elf_loader at cycle "); |
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| 332 | reset_putd( proctime() ); |
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| 333 | reset_puts(" / boot entry = "); |
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| 334 | reset_putx( (unsigned int)(elf_ehdr_ptr->e_entry) ); |
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| 335 | reset_puts("\n"); |
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[425] | 336 | |
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| 337 | return ((void *) elf_ehdr_ptr->e_entry); |
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[292] | 338 | } |
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[425] | 339 | |
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| 340 | // vim: tabstop=4 : softtabstop=4 : shiftwidth=4 : expandtab |
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