opencode.energia.arti.ee
1dc99443b7
Fetch and verify the four MAME indy_4610 PROM dumps, wrap the newest dump in an ELF32 BE MIPS image for Ghidra/REA, and record the resulting structural map: image layout, exception vector table, boot flow, function anchors and firmware feature clusters.
116 lines
2.9 KiB
Python
Executable File
116 lines
2.9 KiB
Python
Executable File
#!/usr/bin/env python3
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"""Wrap a raw SGI Indy IP24 PROM dump in a minimal ELF32 big-endian MIPS image.
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REA's Ghidra MIPS lane accepts ELF32 ET_EXEC images, but not headerless MIPS
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binaries. This tool produces a load-image-only wrapper so the PROM can be
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opened at its real physical address (0x1FC00000) without modifying the ROM
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bytes.
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The wrapper deliberately declares EF_MIPS_ARCH_32 with an unspecified ABI and
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provides no PT_MIPS_ABIFLAGS record. That selects REA's "recordless legacy"
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admission, which pins Ghidra to MIPS:BE:32:default, a suitable match for the
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R4000/R4600-era Indy PROM.
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"""
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from __future__ import annotations
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import argparse
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import os
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import struct
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import sys
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ROM_BASE = 0x1FC00000
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PAGE_SIZE = 0x1000
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EM_MIPS = 8
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ET_EXEC = 2
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EF_MIPS_ARCH_32 = 0x50000000
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EI_NIDENT = 16
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def build_elf(rom: bytes, base: int, entry: int) -> bytes:
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payload_offset = PAGE_SIZE
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e_ident = bytearray(EI_NIDENT)
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e_ident[0:4] = b"\x7fELF"
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e_ident[4] = 1 # ELFCLASS32
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e_ident[5] = 2 # ELFDATA2MSB
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e_ident[6] = 1 # EV_CURRENT
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e_ident[7] = 0 # ELFOSABI_NONE
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e_entry = entry
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e_phoff = 52
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e_shoff = 0
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e_flags = EF_MIPS_ARCH_32
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e_ehsize = 52
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e_phentsize = 32
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e_phnum = 1
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e_shentsize = 0
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e_shnum = 0
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e_shstrndx = 0
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ehdr = struct.pack(
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">16sHHIIIIIHHHHHH",
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bytes(e_ident),
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ET_EXEC,
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EM_MIPS,
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1,
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e_entry,
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e_phoff,
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e_shoff,
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e_flags,
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e_ehsize,
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e_phentsize,
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e_phnum,
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e_shentsize,
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e_shnum,
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e_shstrndx,
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)
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# PT_LOAD: file offset 0x1000 -> virtual address base, whole ROM.
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phdr = struct.pack(
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">IIIIIIII",
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1, # PT_LOAD
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payload_offset,
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base,
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base,
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len(rom),
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len(rom),
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5, # PF_R | PF_X
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PAGE_SIZE,
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)
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header = ehdr + phdr
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assert len(header) <= payload_offset
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return header.ljust(payload_offset, b"\x00") + rom
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def main() -> int:
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parser = argparse.ArgumentParser(description=__doc__)
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parser.add_argument("rom", help="raw PROM binary (512 KiB)")
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parser.add_argument("-o", "--output", help="output ELF path")
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parser.add_argument("--base", type=lambda s: int(s, 0), default=ROM_BASE)
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parser.add_argument("--entry", type=lambda s: int(s, 0), default=None)
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args = parser.parse_args()
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with open(args.rom, "rb") as fh:
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rom = fh.read()
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if len(rom) != 0x80000:
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print(
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f"warning: {args.rom} is {len(rom)} bytes, expected 524288", file=sys.stderr
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)
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entry = args.base if args.entry is None else args.entry
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out = args.output
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if out is None:
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stem, _ = os.path.splitext(args.rom)
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out = stem + ".elf"
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with open(out, "wb") as fh:
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fh.write(build_elf(rom, args.base, entry))
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print(out)
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return 0
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if __name__ == "__main__":
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raise SystemExit(main())
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