scripts: add support for Sercomm kernel header
This scripts creates custom kernel header that necessary for Sercomm mt7621 devices: - Sercomm S3 - Beeline SmartBox Giga - Beeline SmartBox Pro - Beeline Smartbox Turbo - Beeline Smartbox Turbo+ - WiFire S1500.NBN Header format ------------- +--------+---------------+------------------------+ | Offset | Value | Description | +========+===============+========================+ | 0x0 | 53 65 72 00 | Magic "Ser." | +--------+---------------+------------------------+ | 0x4 | 04 00 00 01 | End offset of RootFS | +--------+---------------+------------------------+ | | | This header checksum | | 0x8 | d6 14 9a c1 | htonl(~crc) | +--------+---------------+------------------------+ | 0xc | 02 ff ff ff | Constant | +--------+---------------+------------------------+ | 0x10 | 00 01 40 00 | Kernel start offset | +--------+---------------+------------------------+ | 0x14 | c6 94 24 00 | Kernel length | +--------+---------------+------------------------+ | | | Kernel checksum | | 0x18 | e7 78 89 f1 | htonl(~crc) | +--------+---------------+------------------------+ | 0x1c | 00 00 00 00 | Constant | +--------+---------------+------------------------+ | 0x20 | ff ff ff ff | Constant | +--------+---------------+------------------------+ | 0x24 | ff ff ff ff | Constant | +--------+---------------+------------------------+ | 0x28 | 00 00 00 01 | RootFS offset | +--------+---------------+------------------------+ | | | RootFS length | | 0x2c | 04 00 00 00 | Always 0x4, we check | | | | UBI magic only | +--------+---------------+------------------------+ | | | RootFS checksum | | 0x30 | 1c fc 55 2d | htonl(~crc) | | | | Const for UBI magic | +--------+---------------+------------------------+ | 0x34 | 00 00 00 00 | Constant | +--------+---------------+------------------------+ | 0x38 | ff ff ff ff … | Pad to 0x100 | +--------+---------------+------------------------+ Signed-off-by: Mikhail Zhilkin <csharper2005@gmail.com>
This commit is contained in:
Mikhail Zhilkin
Hauke Mehrtens
parent
442708dfe2
commit
87092b3c06
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@ -0,0 +1,121 @@
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#!/usr/bin/env python3
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"""
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# SPDX-License-Identifier: GPL-2.0-or-later
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#
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# sercomm-kernel-header.py: Creates Sercomm kernel header
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#
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# Copyright © 2022 Mikhail Zhilkin
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"""
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import argparse
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import binascii
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import os
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import struct
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KERNEL_HEADER_SIZE = 0x100
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PADDING = 0xff
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ROOTFS_FAKE_HEADER = "UBI#"
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def auto_int(x):
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return int(x, 0)
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def create_kernel_header(args):
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out_file = open(args.header_file, "wb")
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header = get_kernel_header(args)
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out_file.write(header)
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out_file.close()
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def get_kernel_header(args):
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header = bytearray([PADDING] * KERNEL_HEADER_SIZE)
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struct.pack_into('<L', header, 0xc, 0xffffff02)
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struct.pack_into('<L', header, 0x1c, 0x0)
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struct.pack_into('<L', header, 0x34, 0x0)
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struct.pack_into('<L', header, 0x10, args.kernel_offset)
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struct.pack_into('<L', header, 0x28, args.rootfs_offset)
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if (args.rootfs_file):
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if (args.rootfs_checking_size):
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rootfs_size = args.rootfs_checking_size
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else:
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rootfs_size = os.path.getsize(args.rootfs_file)
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buf = open(args.rootfs_file,'rb').read(rootfs_size)
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crc = binascii.crc32(buf) & 0xffffffff
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else:
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rootfs_size = len(ROOTFS_FAKE_HEADER)
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crc = binascii.crc32(str.encode(ROOTFS_FAKE_HEADER)) & \
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0xffffffff
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struct.pack_into('<L', header, 0x2c, rootfs_size)
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struct.pack_into('<L', header, 0x30, crc)
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rootfs_end_offset = args.rootfs_offset + rootfs_size
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struct.pack_into('<L', header, 0x4, rootfs_end_offset)
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kernel_size = os.path.getsize(args.kernel_file)
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struct.pack_into('<L', header, 0x14, kernel_size)
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buf = open(args.kernel_file,'rb').read()
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crc = binascii.crc32(buf) & 0xffffffff
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struct.pack_into('<L', header, 0x18, crc)
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crc = binascii.crc32(header) & 0xffffffff
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struct.pack_into('<L', header, 0x8, crc)
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struct.pack_into('<L', header, 0x0, 0x726553)
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return header
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def main():
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global args
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parser = argparse.ArgumentParser(description='This script generates \
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a kernel header for the Sercomm mt7621 devices')
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parser.add_argument('--kernel-image',
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dest='kernel_file',
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action='store',
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type=str,
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help='Path to a Kernel binary image')
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parser.add_argument('--kernel-offset',
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dest='kernel_offset',
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action='store',
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type=auto_int,
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help='Kernel offset')
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parser.add_argument('--rootfs-offset',
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dest='rootfs_offset',
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action='store',
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type=auto_int,
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help='RootFS offset')
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parser.add_argument('--output-header',
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dest='header_file',
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action='store',
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type=str,
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help='Output kernel header file')
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parser.add_argument('--rootfs-image',
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dest='rootfs_file',
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action='store',
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type=str,
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help='Path to RootFS binary image (optional)')
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parser.add_argument('--rootfs-checking-size',
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dest='rootfs_checking_size',
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action='store',
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type=auto_int,
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help='Bytes count for CRC calculation (optional)')
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args = parser.parse_args()
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if ((not args.kernel_file) or
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(not args.kernel_offset) or
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(not args.rootfs_offset) or
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(not args.header_file)):
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parser.print_help()
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exit()
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create_kernel_header(args)
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main()
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