UC_ERR_INSN_INVALID while emulating the mrc arm32 instruction.

[F1o0T]

Although, there is already an implementation for the mrc instruction in this commit

The following code doesn't work, although capstone is able to disassemble that instuction

#!/usr/bin/env python

from __future__ import print_function
from unicorn import *
from unicorn.arm_const import *
from capstone import *

# code to be emulated
ARM_CODE   = b"\x31\x0f\x19\xee"
ADDRESS    = 0x10000


# callback for tracing basic blocks
def hook_block(uc, address, size, user_data):
    print(">>> Tracing basic block at 0x%x, block size = 0x%x" %(address, size))


# callback for tracing instructions
def hook_code(uc, address, size, user_data):
    print(">>> Tracing instruction at 0x%x, instruction size = 0x%x" %(address, size))


# Test ARM
def test_arm():
    print("Emulate ARM code")
    # Initialize emulator in ARM mode
    mu = Uc(UC_ARCH_ARM, UC_MODE_ARM)

    # map 2MB memory for this emulation
    mu.mem_map(ADDRESS, 2 * 1024 * 1024)

    # write machine code to be emulated to memory
    mu.mem_write(ADDRESS, ARM_CODE)

    # tracing all basic blocks with customized callback
    mu.hook_add(UC_HOOK_BLOCK, hook_block)

    # tracing one instruction at ADDRESS with customized callback
    mu.hook_add(UC_HOOK_CODE, hook_code, begin=ADDRESS, end=ADDRESS)

    md = Cs(CS_ARCH_ARM, CS_MODE_ARM)
    for insn in md.disasm(ARM_CODE, ADDRESS):
        print("0x%x:\t%s\t%s" % (insn.address, insn.mnemonic, insn.op_str))

    # emulate machine code in infinite time
    mu.emu_start(ADDRESS, ADDRESS + len(ARM_CODE))


if __name__ == '__main__':
    test_arm()

Here is the output.

python3 testMRC.py
Emulate ARM code
0x10000:	mrc	p15, #0, r0, c9, c1, #1
>>> Tracing basic block at 0x10000, block size = 0x4
Traceback (most recent call last):
  File "/home/f1o0t/projects/testUnicorn/bindings/python/testMRC.py", line 50, in <module>
    test_arm()
  File "/home/f1o0t/projects/testUnicorn/bindings/python/testMRC.py", line 46, in test_arm
    mu.emu_start(ADDRESS, ADDRESS + len(ARM_CODE))
  File "/home/f1o0t/projects/testUnicorn/bindings/python/unicorn/unicorn.py", line 547, in emu_start
    raise UcError(status)
unicorn.unicorn.UcError: Invalid instruction (UC_ERR_INSN_INVALID)

Any idea how can I let unicron intepret this instruction successfully?

[wtdcode]

Did you try dev branch? I have pushed a possible related fix.

[F1o0T]

I have just tried the dev branch, and it did'nt work. Still I see the same error.

[wtdcode]

I checked a bit. The coprocessor register you are accessing doesn't exist. Please try another CPU model and refer to ARM documents for further information.