""" Please make sure you read the README file COMPLETELY BEFORE reading anything below.
It is very critical that you read coding guidelines in Section E in README file.
"""
""" Note for adding new register support:
1. Add target register to "supported registers" in the docstring of DecodeSysreg
2. Populate _SYSREG_TO_DECODE_FUNC_MAP with your implementation, optionally using
_SYSREG_TO_DOCNAME_MAP
3. Populate _SUPPORTED_SYSREGS list with target register
"""
from xnu import *
import os
import sys
import xml.etree.ElementTree as ET
GREEN = '\033[0;32m'
RED = '\033[0;31m'
NC = '\033[0m'
_SUPPORTED_SYSREGS = ['ESR_EL1']
_SYSREG_DOC_PATH = os.path.dirname(os.path.abspath(__file__)) + '/sysregdoc/'
_SYSREG_TO_DOCNAME_MAP = {
'ESR_EL1': 'AArch64-esr_el1.xml'
}
_SYSREG_TO_DECODE_FUNC_MAP = None
@lldb_command('decode_sysreg')
def DecodeSysreg(cmd_args=None):
""" Print out human-understandable explanation of a system register value
usage: decode_sysreg <sysreg> <value>
example: decode_sysreg esr_el1 0x96000021
supported registers:
ESR_EL1
"""
if not cmd_args or len(cmd_args) != 2:
raise ArgumentError("Missing arguments.")
reg_name = cmd_args[0].upper()
reg_value = int(cmd_args[1], 0)
if reg_name not in _SUPPORTED_SYSREGS:
raise ArgumentError("{} is not supported".format(reg_name))
_SYSREG_TO_DECODE_FUNC_MAP[reg_name](reg_value)
lldb_alias('decode_esr', 'decode_sysreg esr_el1')
def PrintEsrEl1Explanation(regval):
""" Print out a detailed explanation of regval regarded as the value of
ESR_EL1, by parsing ARM machine readable specification
"""
xmlfilename = _SYSREG_DOC_PATH + _SYSREG_TO_DOCNAME_MAP['ESR_EL1']
tree = ET.parse(xmlfilename)
root = tree.getroot()
ec = (regval >> 26) & ((1 << 6) - 1)
ecstring = '0b{:06b}'.format(ec)
print _Colorify(VT.Green, 'EC == ' + ecstring)
ecxpath = './registers/register/reg_fieldsets/fields/field[@id="EC_31_26"]/field_values/field_value_instance[field_value="{}"]/field_value_description//para'.format(ecstring)
ec_desc_paras = root.findall(ecxpath)
if ec_desc_paras is None or len(ec_desc_paras) == 0:
print 'EC not defined.'
print '\r\n'
for para in ec_desc_paras:
sys.stdout.write(para.text)
for child in para:
sys.stdout.write(_GetParaChildrenStr(child))
sys.stdout.write(child.tail)
print '\r\n'
print '\r\n'
iss = regval & ((1 << 25) - 1);
issstring = '0x{:07x}'.format(iss)
print _Colorify(VT.Green, 'ISS == ' + issstring)
print '\r\n'
iss_condition_xpath = './registers/register/reg_fieldsets/fields/field[@id="EC_31_26"]/field_values/field_value_instance[field_value="{}"]/field_value_links_to'.format(ecstring)
iss_condition = root.find(iss_condition_xpath)
iss_condition_str = iss_condition.attrib['linked_field_condition']
iss_fields_xpath = './registers/register/reg_fieldsets/fields/field[@id="ISS_24_0"]/partial_fieldset/fields[fields_instance="{}"]//field'.format(iss_condition_str)
iss_fields = root.findall(iss_fields_xpath)
for field in iss_fields:
_PrintEsrIssField(field, regval)
def _GetParaChildrenStr(elem):
""" Convert child tags of <para> element into text for printing
"""
if elem.tag == 'binarynumber':
return elem.text
if elem.tag == 'arm-defined-word':
return elem.text
elif elem.tag == 'xref':
return elem.attrib['browsertext'].encode('utf-8')
elif elem.tag == 'register_link':
return elem.text
else:
return _Colorify(VT.Red, '*unsupported text*')
def _PrintEsrIssField(elem, regval):
""" Print detailed explanation of the ISS field of ESR
"""
field_name_str = elem.find('field_name').text
field_msb = int(elem.find('field_msb').text)
field_lsb = int(elem.find('field_lsb').text)
fd_before_paras = elem.findall('./field_description[@order="before"]//para')
fd_after_paras = elem.findall('./field_description[@order="after"]//para')
field_bits = field_msb - field_lsb + 1
field_value = (regval >> field_lsb) & ((1 << field_bits) - 1)
field_value_string = ('0b{:0' + '{}'.format(field_bits) + 'b}').format(field_value)
print _Colorify(VT.Green, _GetIndentedString(2, field_name_str) + ' == ' + field_value_string)
fv_desc_paras = elem.findall('./field_values/field_value_instance[field_value="{}"]/field_value_description//para'.format(field_value_string))
if fv_desc_paras and len(fv_desc_paras):
for para in fv_desc_paras:
sys.stdout.write(_GetIndentedString(2, ''))
sys.stdout.write(para.text)
for child in para:
sys.stdout.write(_GetParaChildrenStr(child))
sys.stdout.write((child.tail))
print '\r\n'
print '\r\n'
else:
print _Colorify(VT.Red, _GetIndentedString(2, '(No matching value, dumping out full description)'))
for para in fd_before_paras:
sys.stdout.write(_GetIndentedString(2, ''))
sys.stdout.write(para.text)
for child in para:
sys.stdout.write(_GetParaChildrenStr(child))
sys.stdout.write(child.tail)
print '\r\n'
print '\r\n'
all_field_values = elem.findall('./field_values/field_value_instance//field_value')
all_field_values_str = [fv.text for fv in all_field_values]
if all_field_values_str != []:
print _GetIndentedString(2, ', '.join(all_field_values_str))
for para in fd_after_paras:
sys.stdout.write(_GetIndentedString(2, ''))
sys.stdout.write(para.text)
for child in para:
sys.stdout.write(_GetParaChildrenStr(child))
sys.stdout.write(child.tail)
print '\r\n'
print '\r\n'
def _GetIndentedString(indentation, msg):
""" Return `msg` indented by `indentation` number of spaces
"""
return ' ' * indentation + msg
def _Colorify(color, msg):
""" Return `msg` enclosed by color codes
"""
return color + msg + VT.Reset
_SYSREG_TO_DECODE_FUNC_MAP = {
'ESR_EL1': PrintEsrEl1Explanation
}