Lee Kai Xuan / mbed-os

mbed-os

Fork of mbed-os by erkin yucel

tools/patch.py@0:f269e3021894, 2016-10-23 (annotated)

Committer:
elessair
Date:
Sun Oct 23 15:10:02 2016 +0000
Revision:
0:f269e3021894
Initial commit

Who changed what in which revision?

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elessair 0:f269e3021894 1 """
elessair 0:f269e3021894 2 mbed SDK
elessair 0:f269e3021894 3 Copyright (c) 2011-2013 ARM Limited
elessair 0:f269e3021894 4
elessair 0:f269e3021894 5 Licensed under the Apache License, Version 2.0 (the "License");
elessair 0:f269e3021894 6 you may not use this file except in compliance with the License.
elessair 0:f269e3021894 7 You may obtain a copy of the License at
elessair 0:f269e3021894 8
elessair 0:f269e3021894 9 http://www.apache.org/licenses/LICENSE-2.0
elessair 0:f269e3021894 10
elessair 0:f269e3021894 11 Unless required by applicable law or agreed to in writing, software
elessair 0:f269e3021894 12 distributed under the License is distributed on an "AS IS" BASIS,
elessair 0:f269e3021894 13 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
elessair 0:f269e3021894 14 See the License for the specific language governing permissions and
elessair 0:f269e3021894 15 limitations under the License.
elessair 0:f269e3021894 16
elessair 0:f269e3021894 17
elessair 0:f269e3021894 18 http://www.nxp.com/documents/user_manual/UM10360.pdf
elessair 0:f269e3021894 19
elessair 0:f269e3021894 20 32.3.1.1 Criterion for Valid User Code
elessair 0:f269e3021894 21 The reserved Cortex-M3 exception vector location 7 (offset 0x1C in the vector table)
elessair 0:f269e3021894 22 should contain the 2's complement of the check-sum of table entries 0 through 6. This
elessair 0:f269e3021894 23 causes the checksum of the first 8 table entries to be 0. The boot loader code checksums
elessair 0:f269e3021894 24 the first 8 locations in sector 0 of the flash. If the result is 0, then execution control is
elessair 0:f269e3021894 25 transferred to the user code.
elessair 0:f269e3021894 26 """
elessair 0:f269e3021894 27 from struct import unpack, pack
elessair 0:f269e3021894 28
elessair 0:f269e3021894 29
elessair 0:f269e3021894 30 def patch(bin_path):
elessair 0:f269e3021894 31 with open(bin_path, 'r+b') as bin:
elessair 0:f269e3021894 32 # Read entries 0 through 6 (Little Endian 32bits words)
elessair 0:f269e3021894 33 vector = [unpack('<I', bin.read(4))[0] for _ in range(7)]
elessair 0:f269e3021894 34
elessair 0:f269e3021894 35 # location 7 (offset 0x1C in the vector table) should contain the 2's
elessair 0:f269e3021894 36 # complement of the check-sum of table entries 0 through 6
elessair 0:f269e3021894 37 bin.seek(0x1C)
elessair 0:f269e3021894 38 bin.write(pack('<I', (~sum(vector) + 1) & 0xFFFFFFFF))
elessair 0:f269e3021894 39
elessair 0:f269e3021894 40
elessair 0:f269e3021894 41 def is_patched(bin_path):
elessair 0:f269e3021894 42 with open(bin_path, 'rb') as bin:
elessair 0:f269e3021894 43 # The checksum of the first 8 table entries should be 0
elessair 0:f269e3021894 44 return (sum([unpack('<I', bin.read(4))[0] for _ in range(8)]) & 0xFFFFFFFF) == 0
elessair 0:f269e3021894 45
elessair 0:f269e3021894 46
elessair 0:f269e3021894 47 if __name__ == '__main__':
elessair 0:f269e3021894 48 bin_path = "C:/Users/emimon01/releases/emilmont/build/test/LPC1768/ARM/MBED_A1/basic.bin"
elessair 0:f269e3021894 49 patch(bin_path)
elessair 0:f269e3021894 50 assert is_patched(bin_path), "The file is not patched"