Alessandro Angelino / mbed-tools

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patch.py@12:fd03da96c01a, 2016-04-05 (annotated)

Committer:
Alessandro Angelino
Date:
Tue Apr 05 17:23:39 2016 +0100
Revision:
12:fd03da96c01a
Parent:
0:4a2e5f0422d6 
Disable the FPU only if UVISOR_PRESENT=1 is defined

Who changed what in which revision?

UserRevisionLine numberNew contents of line
screamer 0:4a2e5f0422d6 1 """
screamer 0:4a2e5f0422d6 2 mbed SDK
screamer 0:4a2e5f0422d6 3 Copyright (c) 2011-2013 ARM Limited
screamer 0:4a2e5f0422d6 4
screamer 0:4a2e5f0422d6 5 Licensed under the Apache License, Version 2.0 (the "License");
screamer 0:4a2e5f0422d6 6 you may not use this file except in compliance with the License.
screamer 0:4a2e5f0422d6 7 You may obtain a copy of the License at
screamer 0:4a2e5f0422d6 8
screamer 0:4a2e5f0422d6 9 http://www.apache.org/licenses/LICENSE-2.0
screamer 0:4a2e5f0422d6 10
screamer 0:4a2e5f0422d6 11 Unless required by applicable law or agreed to in writing, software
screamer 0:4a2e5f0422d6 12 distributed under the License is distributed on an "AS IS" BASIS,
screamer 0:4a2e5f0422d6 13 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
screamer 0:4a2e5f0422d6 14 See the License for the specific language governing permissions and
screamer 0:4a2e5f0422d6 15 limitations under the License.
screamer 0:4a2e5f0422d6 16
screamer 0:4a2e5f0422d6 17
screamer 0:4a2e5f0422d6 18 http://www.nxp.com/documents/user_manual/UM10360.pdf
screamer 0:4a2e5f0422d6 19
screamer 0:4a2e5f0422d6 20 32.3.1.1 Criterion for Valid User Code
screamer 0:4a2e5f0422d6 21 The reserved Cortex-M3 exception vector location 7 (offset 0x1C in the vector table)
screamer 0:4a2e5f0422d6 22 should contain the 2's complement of the check-sum of table entries 0 through 6. This
screamer 0:4a2e5f0422d6 23 causes the checksum of the first 8 table entries to be 0. The boot loader code checksums
screamer 0:4a2e5f0422d6 24 the first 8 locations in sector 0 of the flash. If the result is 0, then execution control is
screamer 0:4a2e5f0422d6 25 transferred to the user code.
screamer 0:4a2e5f0422d6 26 """
screamer 0:4a2e5f0422d6 27 from struct import unpack, pack
screamer 0:4a2e5f0422d6 28
screamer 0:4a2e5f0422d6 29
screamer 0:4a2e5f0422d6 30 def patch(bin_path):
screamer 0:4a2e5f0422d6 31 with open(bin_path, 'r+b') as bin:
screamer 0:4a2e5f0422d6 32 # Read entries 0 through 6 (Little Endian 32bits words)
screamer 0:4a2e5f0422d6 33 vector = [unpack('<I', bin.read(4))[0] for _ in range(7)]
screamer 0:4a2e5f0422d6 34
screamer 0:4a2e5f0422d6 35 # location 7 (offset 0x1C in the vector table) should contain the 2's
screamer 0:4a2e5f0422d6 36 # complement of the check-sum of table entries 0 through 6
screamer 0:4a2e5f0422d6 37 bin.seek(0x1C)
screamer 0:4a2e5f0422d6 38 bin.write(pack('<I', (~sum(vector) + 1) & 0xFFFFFFFF))
screamer 0:4a2e5f0422d6 39
screamer 0:4a2e5f0422d6 40
screamer 0:4a2e5f0422d6 41 def is_patched(bin_path):
screamer 0:4a2e5f0422d6 42 with open(bin_path, 'rb') as bin:
screamer 0:4a2e5f0422d6 43 # The checksum of the first 8 table entries should be 0
screamer 0:4a2e5f0422d6 44 return (sum([unpack('<I', bin.read(4))[0] for _ in range(8)]) & 0xFFFFFFFF) == 0
screamer 0:4a2e5f0422d6 45
screamer 0:4a2e5f0422d6 46
screamer 0:4a2e5f0422d6 47 if __name__ == '__main__':
screamer 0:4a2e5f0422d6 48 bin_path = "C:/Users/emimon01/releases/emilmont/build/test/LPC1768/ARM/MBED_A1/basic.bin"
screamer 0:4a2e5f0422d6 49 patch(bin_path)
screamer 0:4a2e5f0422d6 50 assert is_patched(bin_path), "The file is not patched"