Add a new apcb edit tool, apcb_v3a_edit.py, that injects SPDs into an APCB for phoenix platform. The tool makes several assumptions: * Each SPD only uses blocks 0, 1, 3 and 5. All other blocks are zero. * Each block is 64 bytes. * Dimm and socket are always 0 * Unused SPD entries are zero'd BUG=b:281983434 BRANCH=None TEST=build, flash, boot myst Change-Id: Ifb50287de77138170714a702ab87d56427aacfef Signed-off-by: Rob Barnes <robbarnes@google.com> Reviewed-on: https://review.coreboot.org/c/coreboot/+/76188 Reviewed-by: Karthik Ramasubramanian <kramasub@google.com> Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
		
			
				
	
	
		
			131 lines
		
	
	
		
			4.1 KiB
		
	
	
	
		
			Python
		
	
	
		
			Executable File
		
	
	
	
	
			
		
		
	
	
			131 lines
		
	
	
		
			4.1 KiB
		
	
	
	
		
			Python
		
	
	
		
			Executable File
		
	
	
	
	
#!/usr/bin/env python3
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# Script for injecting SPDs into APCB_v3a binaries.
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import re
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import argparse
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from collections import namedtuple
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from struct import *
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APCB_CHECKSUM_OFFSET = 16
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SPD_ENTRY_MAGIC = bytes.fromhex('0200480000000000')
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SPD_SIZE = 512
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EMPTY_SPD = b'\x00' * SPD_SIZE
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ZERO_BLOCKS = (2, 4, 6, 7)
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SPD_BLOCK_SIZE = 64
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SPD_BLOCK_HEADER_FMT = '<HHHH'
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SPD_BLOCK_HEADER_SIZE = calcsize(SPD_BLOCK_HEADER_FMT)
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spd_block_header = namedtuple(
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    'spd_block_header', 'Type, Length, Key, Reserved')
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def parseargs():
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    parser = argparse.ArgumentParser(description='Inject SPDs into APCB binaries')
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    parser.add_argument(
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        'apcb_in',
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        type=str,
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        help='APCB input file')
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    parser.add_argument(
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        'apcb_out',
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        type=str,
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        help='APCB output file')
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    parser.add_argument(
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        '--spd_sources',
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        nargs='+',
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        help='List of SPD sources')
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    return parser.parse_args()
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# Calculate checksum of APCB binary
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def chksum(data):
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    sum = 0
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    for i, v in enumerate(data):
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        if i == APCB_CHECKSUM_OFFSET: continue
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        sum = (sum + v) & 0xff
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    return (0x100 - sum) & 0xff
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# Inject bytes into binary blob by overwriting
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def inject(orig, insert, offset):
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    return b''.join([orig[:offset], insert, orig[offset + len(insert):]])
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def main():
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    args = parseargs()
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    # Load input APCB
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    print(f'Reading input APCB from {args.apcb_in}')
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    with open(args.apcb_in, 'rb') as f:
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        apcb = f.read()
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    assert chksum(apcb) == apcb[APCB_CHECKSUM_OFFSET], 'Initial checksum is invalid'
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    orig_apcb_len = len(apcb)
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    # Load SPDs
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    print(f'Using SPD Sources = {", ".join(args.spd_sources)}')
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    spds = []
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    for spd_source in args.spd_sources:
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        with open(spd_source, 'rb') as f:
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            spd_data = bytes.fromhex(re.sub(r'\s+', '', f.read().decode()))
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        assert len(spd_data) == SPD_SIZE, f'{spd_source} is not {SPD_SIZE} bytes'
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        # Verify ZERO_BLOCKS are zero
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        for b in ZERO_BLOCKS:
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            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'
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        spds.append(spd_data)
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    assert len(spds) > 0, "No SPDs provided"
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    # Inject SPDs into APCB
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    apcb_offset = 0
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    spd_idx = 0
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    while True:
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        apcb_offset = apcb.find(SPD_ENTRY_MAGIC, apcb_offset)
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        if apcb_offset < 0:
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            print(f'No more SPD entries found')
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            assert spd_idx >= len(spds), f'Not enough SPD entries in APCB. Need {len(spds)}, found {spd_idx}'
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            break
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        if spd_idx < len(spds):
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            print(f'Injecting SPD instance {spd_idx}')
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            spd = spds[spd_idx]
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        else:
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            print(f'Injecting empty SPD for instance {spd_idx}')
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            spd = EMPTY_SPD
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        # Inject SPD blocks
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        for b in range(int(SPD_SIZE/SPD_BLOCK_SIZE)):
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            if b in ZERO_BLOCKS: continue
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            header_data = apcb[apcb_offset:apcb_offset + SPD_BLOCK_HEADER_SIZE]
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            header = spd_block_header._make(unpack(SPD_BLOCK_HEADER_FMT, header_data))
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            socket = (header.Key >> 12) & 0xF
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            channel = (header.Key >> 8) & 0xF
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            dimm = (header.Key >> 4) & 0xF
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            block_id = (header.Key >> 0) & 0xF
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            assert header.Type == 2
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            assert header.Length == SPD_BLOCK_HEADER_SIZE + SPD_BLOCK_SIZE
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            assert socket == 0
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            assert channel == 0
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            assert block_id == b
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            assert dimm == 0
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            assert header.Reserved == 0
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            spd_block = spd[b*SPD_BLOCK_SIZE:(b+1)*SPD_BLOCK_SIZE]
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            apcb_offset += SPD_BLOCK_HEADER_SIZE
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            apcb = inject(apcb, spd_block, apcb_offset)
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            apcb_offset += SPD_BLOCK_SIZE
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        spd_idx += 1
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    # Fix APCB checksum
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    print(f'Fixing APCB checksum')
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    apcb = inject(apcb, bytes([chksum(apcb)]), APCB_CHECKSUM_OFFSET)
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    assert chksum(apcb) == apcb[APCB_CHECKSUM_OFFSET], 'Final checksum is invalid'
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    assert orig_apcb_len == len(apcb), 'The size of the APCB changed.'
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    # Write APCB to file
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    print(f'Writing {len(apcb)} byte APCB to {args.apcb_out}')
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    with open(args.apcb_out, 'wb') as f:
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        f.write(apcb)
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if __name__ == "__main__":
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    main()
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