131 lines
4.1 KiB
Python
Executable File
131 lines
4.1 KiB
Python
Executable File
#!/usr/bin/env python3
|
|
|
|
# Script for injecting SPDs into APCB_v3a binaries.
|
|
|
|
import re
|
|
import argparse
|
|
from collections import namedtuple
|
|
from struct import *
|
|
|
|
APCB_CHECKSUM_OFFSET = 16
|
|
SPD_ENTRY_MAGIC = bytes.fromhex('0200480000000000')
|
|
SPD_SIZE = 512
|
|
EMPTY_SPD = b'\x00' * SPD_SIZE
|
|
ZERO_BLOCKS = (2, 4, 6, 7)
|
|
SPD_BLOCK_SIZE = 64
|
|
SPD_BLOCK_HEADER_FMT = '<HHHH'
|
|
SPD_BLOCK_HEADER_SIZE = calcsize(SPD_BLOCK_HEADER_FMT)
|
|
spd_block_header = namedtuple(
|
|
'spd_block_header', 'Type, Length, Key, Reserved')
|
|
|
|
def parseargs():
|
|
parser = argparse.ArgumentParser(description='Inject SPDs into APCB binaries')
|
|
parser.add_argument(
|
|
'apcb_in',
|
|
type=str,
|
|
help='APCB input file')
|
|
parser.add_argument(
|
|
'apcb_out',
|
|
type=str,
|
|
help='APCB output file')
|
|
parser.add_argument(
|
|
'--spd_sources',
|
|
nargs='+',
|
|
help='List of SPD sources')
|
|
return parser.parse_args()
|
|
|
|
|
|
# Calculate checksum of APCB binary
|
|
def chksum(data):
|
|
sum = 0
|
|
for i, v in enumerate(data):
|
|
if i == APCB_CHECKSUM_OFFSET: continue
|
|
sum = (sum + v) & 0xff
|
|
return (0x100 - sum) & 0xff
|
|
|
|
|
|
# Inject bytes into binary blob by overwriting
|
|
def inject(orig, insert, offset):
|
|
return b''.join([orig[:offset], insert, orig[offset + len(insert):]])
|
|
|
|
|
|
def main():
|
|
args = parseargs()
|
|
|
|
# Load input APCB
|
|
print(f'Reading input APCB from {args.apcb_in}')
|
|
with open(args.apcb_in, 'rb') as f:
|
|
apcb = f.read()
|
|
assert chksum(apcb) == apcb[APCB_CHECKSUM_OFFSET], 'Initial checksum is invalid'
|
|
orig_apcb_len = len(apcb)
|
|
|
|
# Load SPDs
|
|
print(f'Using SPD Sources = {", ".join(args.spd_sources)}')
|
|
spds = []
|
|
for spd_source in args.spd_sources:
|
|
with open(spd_source, 'rb') as f:
|
|
spd_data = bytes.fromhex(re.sub(r'\s+', '', f.read().decode()))
|
|
assert len(spd_data) == SPD_SIZE, f'{spd_source} is not {SPD_SIZE} bytes'
|
|
# Verify ZERO_BLOCKS are zero
|
|
for b in ZERO_BLOCKS:
|
|
assert all(v==0 for v in spd_data[b*SPD_BLOCK_SIZE:(b+1)*SPD_BLOCK_SIZE]), f'SPD block #{b} is not zero'
|
|
spds.append(spd_data)
|
|
assert len(spds) > 0, "No SPDs provided"
|
|
|
|
# Inject SPDs into APCB
|
|
apcb_offset = 0
|
|
spd_idx = 0
|
|
while True:
|
|
apcb_offset = apcb.find(SPD_ENTRY_MAGIC, apcb_offset)
|
|
if apcb_offset < 0:
|
|
print(f'No more SPD entries found')
|
|
assert spd_idx >= len(spds), f'Not enough SPD entries in APCB. Need {len(spds)}, found {spd_idx}'
|
|
break
|
|
|
|
if spd_idx < len(spds):
|
|
print(f'Injecting SPD instance {spd_idx}')
|
|
spd = spds[spd_idx]
|
|
else:
|
|
print(f'Injecting empty SPD for instance {spd_idx}')
|
|
spd = EMPTY_SPD
|
|
|
|
# Inject SPD blocks
|
|
for b in range(int(SPD_SIZE/SPD_BLOCK_SIZE)):
|
|
if b in ZERO_BLOCKS: continue
|
|
header_data = apcb[apcb_offset:apcb_offset + SPD_BLOCK_HEADER_SIZE]
|
|
header = spd_block_header._make(unpack(SPD_BLOCK_HEADER_FMT, header_data))
|
|
socket = (header.Key >> 12) & 0xF
|
|
channel = (header.Key >> 8) & 0xF
|
|
dimm = (header.Key >> 4) & 0xF
|
|
block_id = (header.Key >> 0) & 0xF
|
|
|
|
assert header.Type == 2
|
|
assert header.Length == SPD_BLOCK_HEADER_SIZE + SPD_BLOCK_SIZE
|
|
assert socket == 0
|
|
assert channel == 0
|
|
assert block_id == b
|
|
assert dimm == 0
|
|
assert header.Reserved == 0
|
|
|
|
spd_block = spd[b*SPD_BLOCK_SIZE:(b+1)*SPD_BLOCK_SIZE]
|
|
apcb_offset += SPD_BLOCK_HEADER_SIZE
|
|
apcb = inject(apcb, spd_block, apcb_offset)
|
|
apcb_offset += SPD_BLOCK_SIZE
|
|
|
|
spd_idx += 1
|
|
|
|
# Fix APCB checksum
|
|
print(f'Fixing APCB checksum')
|
|
apcb = inject(apcb, bytes([chksum(apcb)]), APCB_CHECKSUM_OFFSET)
|
|
assert chksum(apcb) == apcb[APCB_CHECKSUM_OFFSET], 'Final checksum is invalid'
|
|
assert orig_apcb_len == len(apcb), 'The size of the APCB changed.'
|
|
|
|
# Write APCB to file
|
|
print(f'Writing {len(apcb)} byte APCB to {args.apcb_out}')
|
|
with open(args.apcb_out, 'wb') as f:
|
|
f.write(apcb)
|
|
|
|
|
|
if __name__ == "__main__":
|
|
main()
|