/gdb-trace.py Secret
Created
October 17, 2016 08:21
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gdb script to emulate the trace command for logging memory reads/writes on Cortex-M targets
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import re | |
from collections import OrderedDict | |
register_names = "pc sp lr r0 r1 r2 r3 r4 r5 r6 r7 r8 r9 r10 r11 r12 xPSR".split(" ") | |
addr_pattern = re.compile(r";\s+\((0x[0-9a-fA-F]{1,8})\)") | |
def get_registers(names=register_names): | |
uint32_t = gdb.lookup_type("unsigned long") | |
d = OrderedDict() | |
for name in names: | |
value = gdb.parse_and_eval("$"+name).cast(uint32_t) | |
d[name] = int(value) | |
return d | |
def step_and_record_while(log, predicate): | |
prev_registers = {} | |
while True: | |
registers = get_registers() | |
changeset = [(reg,val) for (reg,val) in registers.items() if val != prev_registers.get(reg)] | |
prev_registers = registers | |
inst = gdb.execute("x /i $pc", to_string=True) | |
if inst.startswith("=> "): | |
inst = inst[3:] | |
log.write(inst.strip()) | |
if ";" in inst: | |
m = addr_pattern.search(inst) | |
if m is not None: | |
word = gdb.parse_and_eval("*(unsigned long*)({})".format(m.group(1))) | |
log.write(" @#MEM=" + ("0x{:08X}".format(int(word)))) | |
if changeset: | |
log.write(" @#") | |
log.write(",".join("{:s}=0x{:08X}".format(reg,val) for (reg,val) in changeset) + "\n") | |
if not predicate(registers): | |
break | |
gdb.execute("si", to_string=True) | |
def step_through_bootloader(log): | |
def not_in_user_code(registers): | |
return (registers["pc"] <= 0x08004000) | |
step_and_record_while(log, not_in_user_code) | |
def step_until_before_loop(log): | |
def before_loop(registers): | |
if registers["pc"] == 0x8001292: | |
return False | |
return True | |
step_and_record_while(log, before_loop) |
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