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ELF: added support for SHT_RISCV_ATTRIBUTES seg

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This commit is contained in:
Valentin Haudiquet
2023-10-20 16:14:01 +02:00
parent 326b52ef86
commit a0935f0aad
2 changed files with 87 additions and 82 deletions
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168
src/bootloader/elf/elf.c
View File

@@ -8,94 +8,98 @@
uint32_t elf_32_load(void* file)
{
// Parse/verify the header
elf_header_32_t* header = file;
// Parse/verify the header
elf_header_32_t* header = file;
// Verify magic number
uint8_t* m = header->ELF;
if((m[0] != 0x7F) || (m[1] != 'E') || (m[2] != 'L') || (m[3] != 'F'))
{
fprintf(stderr, "Not a valid ELF file (wrong magic)\n");
exit(EXIT_FAILURE);
}
// Verify magic number
uint8_t* m = header->ELF;
if((m[0] != 0x7F) || (m[1] != 'E') || (m[2] != 'L') || (m[3] != 'F'))
{
fprintf(stderr, "Not a valid ELF file (wrong magic)\n");
exit(EXIT_FAILURE);
}
// Verify architecture
if(header->instruction_set != INSTRUCTION_SET_RISCV)
{
switch(header->instruction_set)
{
case INSTRUCTION_SET_X86:
fprintf(stderr, "Provided ELF file targets x86 ; perhaps you forgot to cross-compile ? Please provide a RISC-V ELF\n");
break;
case INSTRUCTION_SET_X86_64:
fprintf(stderr, "Provided ELF file targets x86_64; perhaps you forgot to cross-compile ? Please provide a RISC-V ELF\n");
break;
default:
fprintf(stderr, "Provided ELF file is for an unknown instruction set architecture (0x%x), please provide a RISC-V ELF\n", header->instruction_set);
break;
}
exit(EXIT_FAILURE);
}
// Verify architecture
if(header->instruction_set != INSTRUCTION_SET_RISCV)
{
switch(header->instruction_set)
{
case INSTRUCTION_SET_X86:
fprintf(stderr, "Provided ELF file targets x86 ; perhaps you forgot to cross-compile ? Please provide a RISC-V ELF\n");
break;
case INSTRUCTION_SET_X86_64:
fprintf(stderr, "Provided ELF file targets x86_64; perhaps you forgot to cross-compile ? Please provide a RISC-V ELF\n");
break;
default:
fprintf(stderr, "Provided ELF file is for an unknown instruction set architecture (0x%x), please provide a RISC-V ELF\n", header->instruction_set);
break;
}
exit(EXIT_FAILURE);
}
// Verify bit count
if(header->bits != BITS_32)
{
switch(header->bits)
{
case BITS_64:
fprintf(stderr, "Provided ELF file targets RISC-V 64 bits ; please provide a 32-bits ELF\n");
break;
default:
fprintf(stderr, "Provided ELF file targets an unknown bit count (not 32 bits) ; please provide a 32-bits ELF\n");
break;
}
exit(EXIT_FAILURE);
}
// Verify bit count
if(header->bits != BITS_32)
{
switch(header->bits)
{
case BITS_64:
fprintf(stderr, "Provided ELF file targets RISC-V 64 bits ; please provide a 32-bits ELF\n");
break;
default:
fprintf(stderr, "Provided ELF file targets an unknown bit count (not 32 bits) ; please provide a 32-bits ELF\n");
break;
}
exit(EXIT_FAILURE);
}
// Verify endianness
if(header->endianness != ELF_LITTLE_ENDIAN)
{
fprintf(stderr, "Provided ELF file is encoded in big endian ; please provide a little endian ELF\n");
exit(EXIT_FAILURE);
}
// Verify endianness
if(header->endianness != ELF_LITTLE_ENDIAN)
{
fprintf(stderr, "Provided ELF file is encoded in big endian ; please provide a little endian ELF\n");
exit(EXIT_FAILURE);
}
// File should be correct ; now load it, using program header table
elf_program_header_32_t* program_header = (elf_program_header_32_t*) (((uint8_t*) file) + header->program_header_table_32);
size_t program_header_count = header->program_entry_amount;
for(size_t i = 0; i < program_header_count; i++)
{
elf_program_header_32_t current = program_header[i];
// Check segment type
if(current.segment_type != SEGMENT_TYPE_LOAD)
{
fprintf(stderr, "WARNING: Unknown segment type %u in ELF file ; skipping\n", current.segment_type);
continue;
}
// File should be correct ; now load it, using program header table
elf_program_header_32_t* program_header = (elf_program_header_32_t*) (((uint8_t*) file) + header->program_header_table_32);
size_t program_header_count = header->program_entry_amount;
for(size_t i = 0; i < program_header_count; i++)
{
elf_program_header_32_t current = program_header[i];
// Check memory size
size_t memsz = current.segment_memory_size;
if(!memsz)
{
fprintf(stderr, "WARNING: LOAD segment with null size in ELF file ; skipping\n");
continue;
}
// Check segment type
if(current.segment_type != SEGMENT_TYPE_LOAD)
{
// Don't message for riscv-specific attributes segment
if(current.segment_type != SEGMENT_TYPE_RISCV_SPECIFIC_SHT_RISCV_ATTRIBUTES)
{
fprintf(stderr, "WARNING: Unknown segment type %u in ELF file ; skipping\n", current.segment_type);
}
continue;
}
// Map the segment : first the part in the file, then the zeros
if(memory_size < (current.virtual_address + memsz))
{
fprintf(stderr, "FATAL: Not enough memory while loading ELF file\n");
exit(EXIT_FAILURE);
}
if(current.segment_file_size != 0)
{
memcpy(&memory[current.virtual_address], ((uint8_t*) file) + current.segment_offset, current.segment_file_size);
}
if(memsz > current.segment_file_size)
{
memset(&memory[current.virtual_address] + current.segment_file_size, 0, memsz - current.segment_file_size);
}
}
// Check memory size
size_t memsz = current.segment_memory_size;
if(!memsz)
{
fprintf(stderr, "WARNING: LOAD segment with null size in ELF file ; skipping\n");
continue;
}
return header->entry_32;
// Map the segment : first the part in the file, then the zeros
if(memory_size < (current.virtual_address + memsz))
{
fprintf(stderr, "FATAL: Not enough memory while loading ELF file\n");
exit(EXIT_FAILURE);
}
if(current.segment_file_size != 0)
{
memcpy(&memory[current.virtual_address], ((uint8_t*) file) + current.segment_offset, current.segment_file_size);
}
if(memsz > current.segment_file_size)
{
memset(&memory[current.virtual_address] + current.segment_file_size, 0, memsz - current.segment_file_size);
}
}
return header->entry_32;
}

1
src/bootloader/elf/elf.h
View File

@@ -77,6 +77,7 @@ typedef struct ELF_PROGRAM_HEADER_32
#define SEGMENT_TYPE_DYNAMIC 2
#define SEGMENT_TYPE_INTERP 3
#define SEGMENT_TYPE_NOTE 4
#define SEGMENT_TYPE_RISCV_SPECIFIC_SHT_RISCV_ATTRIBUTES 0x70000003
uint32_t elf_32_load(void* file);