cachepc-qemu

Fork of AMDESE/qemu with changes for cachepc side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-qemu
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dectree.py (13570B)


      1#!/usr/bin/env python3
      2
      3##
      4##  Copyright(c) 2019-2021 Qualcomm Innovation Center, Inc. All Rights Reserved.
      5##
      6##  This program is free software; you can redistribute it and/or modify
      7##  it under the terms of the GNU General Public License as published by
      8##  the Free Software Foundation; either version 2 of the License, or
      9##  (at your option) any later version.
     10##
     11##  This program is distributed in the hope that it will be useful,
     12##  but WITHOUT ANY WARRANTY; without even the implied warranty of
     13##  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     14##  GNU General Public License for more details.
     15##
     16##  You should have received a copy of the GNU General Public License
     17##  along with this program; if not, see <http://www.gnu.org/licenses/>.
     18##
     19
     20import io
     21import re
     22
     23import sys
     24import iset
     25
     26encs = {tag : ''.join(reversed(iset.iset[tag]['enc'].replace(' ', '')))
     27    for tag in iset.tags if iset.iset[tag]['enc'] != 'MISSING ENCODING'}
     28
     29enc_classes = set([iset.iset[tag]['enc_class'] for tag in encs.keys()])
     30subinsn_enc_classes = \
     31    set([enc_class for enc_class in enc_classes \
     32        if enc_class.startswith('SUBINSN_')])
     33ext_enc_classes = \
     34    set([enc_class for enc_class in enc_classes \
     35        if enc_class not in ('NORMAL', '16BIT') and \
     36           not enc_class.startswith('SUBINSN_')])
     37
     38try:
     39    subinsn_groupings = iset.subinsn_groupings
     40except AttributeError:
     41    subinsn_groupings = {}
     42
     43for (tag, subinsn_grouping) in subinsn_groupings.items():
     44    encs[tag] = ''.join(reversed(subinsn_grouping['enc'].replace(' ', '')))
     45
     46dectree_normal = {'leaves' : set()}
     47dectree_16bit = {'leaves' : set()}
     48dectree_subinsn_groupings = {'leaves' : set()}
     49dectree_subinsns = {name : {'leaves' : set()} for name in subinsn_enc_classes}
     50dectree_extensions = {name : {'leaves' : set()} for name in ext_enc_classes}
     51
     52for tag in encs.keys():
     53    if tag in subinsn_groupings:
     54        dectree_subinsn_groupings['leaves'].add(tag)
     55        continue
     56    enc_class = iset.iset[tag]['enc_class']
     57    if enc_class.startswith('SUBINSN_'):
     58        if len(encs[tag]) != 32:
     59            encs[tag] = encs[tag] + '0' * (32 - len(encs[tag]))
     60        dectree_subinsns[enc_class]['leaves'].add(tag)
     61    elif  enc_class == '16BIT':
     62        if len(encs[tag]) != 16:
     63            raise Exception('Tag "{}" has enc_class "{}" and not an encoding ' +
     64                            'width of 16 bits!'.format(tag, enc_class))
     65        dectree_16bit['leaves'].add(tag)
     66    else:
     67        if len(encs[tag]) != 32:
     68            raise Exception('Tag "{}" has enc_class "{}" and not an encoding ' +
     69                            'width of 32 bits!'.format(tag, enc_class))
     70        if enc_class == 'NORMAL':
     71            dectree_normal['leaves'].add(tag)
     72        else:
     73            dectree_extensions[enc_class]['leaves'].add(tag)
     74
     75faketags = set()
     76for (tag, enc) in iset.enc_ext_spaces.items():
     77    faketags.add(tag)
     78    encs[tag] = ''.join(reversed(enc.replace(' ', '')))
     79    dectree_normal['leaves'].add(tag)
     80
     81faketags |= set(subinsn_groupings.keys())
     82
     83def every_bit_counts(bitset):
     84    for i in range(1, len(next(iter(bitset)))):
     85        if len(set([bits[:i] + bits[i+1:] for bits in bitset])) == len(bitset):
     86            return False
     87    return True
     88
     89def auto_separate(node):
     90    tags = node['leaves']
     91    if len(tags) <= 1:
     92        return
     93    enc_width = len(encs[next(iter(tags))])
     94    opcode_bit_for_all = \
     95        [all([encs[tag][i] in '01' \
     96            for tag in tags]) for i in range(enc_width)]
     97    opcode_bit_is_0_for_all = \
     98        [opcode_bit_for_all[i] and all([encs[tag][i] == '0' \
     99            for tag in tags]) for i in range(enc_width)]
    100    opcode_bit_is_1_for_all = \
    101        [opcode_bit_for_all[i] and all([encs[tag][i] == '1' \
    102            for tag in tags]) for i in range(enc_width)]
    103    differentiator_opcode_bit = \
    104        [opcode_bit_for_all[i] and \
    105         not (opcode_bit_is_0_for_all[i] or \
    106         opcode_bit_is_1_for_all[i]) \
    107            for i in range(enc_width)]
    108    best_width = 0
    109    for width in range(4, 0, -1):
    110        for lsb in range(enc_width - width, -1, -1):
    111            bitset = set([encs[tag][lsb:lsb+width] for tag in tags])
    112            if all(differentiator_opcode_bit[lsb:lsb+width]) and \
    113                (len(bitset) == len(tags) or every_bit_counts(bitset)):
    114                best_width = width
    115                best_lsb = lsb
    116                caught_all_tags = len(bitset) == len(tags)
    117                break
    118        if best_width != 0:
    119            break
    120    if best_width == 0:
    121        raise Exception('Could not find a way to differentiate the encodings ' +
    122                         'of the following tags:\n{}'.format('\n'.join(tags)))
    123    if caught_all_tags:
    124        for width in range(1, best_width):
    125            for lsb in range(enc_width - width, -1, -1):
    126                bitset = set([encs[tag][lsb:lsb+width] for tag in tags])
    127                if all(differentiator_opcode_bit[lsb:lsb+width]) and \
    128                    len(bitset) == len(tags):
    129                    best_width = width
    130                    best_lsb = lsb
    131                    break
    132            else:
    133                continue
    134            break
    135    node['separator_lsb'] = best_lsb
    136    node['separator_width'] = best_width
    137    node['children'] = []
    138    for value in range(2 ** best_width):
    139        child = {}
    140        bits = ''.join(reversed('{:0{}b}'.format(value, best_width)))
    141        child['leaves'] = \
    142            set([tag for tag in tags \
    143                if encs[tag][best_lsb:best_lsb+best_width] == bits])
    144        node['children'].append(child)
    145    for child in node['children']:
    146        auto_separate(child)
    147
    148auto_separate(dectree_normal)
    149auto_separate(dectree_16bit)
    150if subinsn_groupings:
    151    auto_separate(dectree_subinsn_groupings)
    152for dectree_subinsn in dectree_subinsns.values():
    153    auto_separate(dectree_subinsn)
    154for dectree_ext in dectree_extensions.values():
    155    auto_separate(dectree_ext)
    156
    157for tag in faketags:
    158    del encs[tag]
    159
    160def table_name(parents, node):
    161    path = parents + [node]
    162    root = path[0]
    163    tag = next(iter(node['leaves']))
    164    if tag in subinsn_groupings:
    165        enc_width = len(subinsn_groupings[tag]['enc'].replace(' ', ''))
    166    else:
    167        tag = next(iter(node['leaves'] - faketags))
    168        enc_width = len(encs[tag])
    169    determining_bits = ['_'] * enc_width
    170    for (parent, child) in zip(path[:-1], path[1:]):
    171        lsb = parent['separator_lsb']
    172        width = parent['separator_width']
    173        value = parent['children'].index(child)
    174        determining_bits[lsb:lsb+width] = \
    175            list(reversed('{:0{}b}'.format(value, width)))
    176    if tag in subinsn_groupings:
    177        name = 'DECODE_ROOT_EE'
    178    else:
    179        enc_class = iset.iset[tag]['enc_class']
    180        if enc_class in ext_enc_classes:
    181            name = 'DECODE_EXT_{}'.format(enc_class)
    182        elif enc_class in subinsn_enc_classes:
    183            name = 'DECODE_SUBINSN_{}'.format(enc_class)
    184        else:
    185            name = 'DECODE_ROOT_{}'.format(enc_width)
    186    if node != root:
    187        name += '_' + ''.join(reversed(determining_bits))
    188    return name
    189
    190def print_node(f, node, parents):
    191    if len(node['leaves']) <= 1:
    192        return
    193    name = table_name(parents, node)
    194    lsb = node['separator_lsb']
    195    width = node['separator_width']
    196    print('DECODE_NEW_TABLE({},{},DECODE_SEPARATOR_BITS({},{}))'.\
    197        format(name, 2 ** width, lsb, width), file=f)
    198    for child in node['children']:
    199        if len(child['leaves']) == 0:
    200            print('INVALID()', file=f)
    201        elif len(child['leaves']) == 1:
    202            (tag,) = child['leaves']
    203            if tag in subinsn_groupings:
    204                class_a = subinsn_groupings[tag]['class_a']
    205                class_b = subinsn_groupings[tag]['class_b']
    206                enc = subinsn_groupings[tag]['enc'].replace(' ', '')
    207                if 'RESERVED' in tag:
    208                    print('INVALID()', file=f)
    209                else:
    210                    print('SUBINSNS({},{},{},"{}")'.\
    211                        format(tag, class_a, class_b, enc), file=f)
    212            elif tag in iset.enc_ext_spaces:
    213                enc = iset.enc_ext_spaces[tag].replace(' ', '')
    214                print('EXTSPACE({},"{}")'.format(tag, enc), file=f)
    215            else:
    216                enc = ''.join(reversed(encs[tag]))
    217                print('TERMINAL({},"{}")'.format(tag, enc), file=f)
    218        else:
    219            print('TABLE_LINK({})'.format(table_name(parents + [node], child)),
    220                  file=f)
    221    print('DECODE_END_TABLE({},{},DECODE_SEPARATOR_BITS({},{}))'.\
    222        format(name, 2 ** width, lsb, width), file=f)
    223    print(file=f)
    224    parents.append(node)
    225    for child in node['children']:
    226        print_node(f, child, parents)
    227    parents.pop()
    228
    229def print_tree(f, tree):
    230    print_node(f, tree, [])
    231
    232def print_match_info(f):
    233    for tag in sorted(encs.keys(), key=iset.tags.index):
    234        enc = ''.join(reversed(encs[tag]))
    235        mask = int(re.sub(r'[^1]', r'0', enc.replace('0', '1')), 2)
    236        match = int(re.sub(r'[^01]', r'0', enc), 2)
    237        suffix = ''
    238        print('DECODE{}_MATCH_INFO({},0x{:x}U,0x{:x}U)'.\
    239            format(suffix, tag, mask, match), file=f)
    240
    241regre = re.compile(
    242    r'((?<!DUP)[MNORCPQXSGVZA])([stuvwxyzdefg]+)([.]?[LlHh]?)(\d+S?)')
    243immre = re.compile(r'[#]([rRsSuUm])(\d+)(?:[:](\d+))?')
    244
    245def ordered_unique(l):
    246    return sorted(set(l), key=l.index)
    247
    248implicit_registers = {
    249    'SP' : 29,
    250    'FP' : 30,
    251    'LR' : 31
    252}
    253
    254num_registers = {
    255    'R' : 32,
    256    'V' : 32
    257}
    258
    259def print_op_info(f):
    260    for tag in sorted(encs.keys(), key=iset.tags.index):
    261        enc = encs[tag]
    262        print(file=f)
    263        print('DECODE_OPINFO({},'.format(tag), file=f)
    264        regs = ordered_unique(regre.findall(iset.iset[tag]['syntax']))
    265        imms = ordered_unique(immre.findall(iset.iset[tag]['syntax']))
    266        regno = 0
    267        for reg in regs:
    268            reg_type = reg[0]
    269            reg_letter = reg[1][0]
    270            reg_num_choices = int(reg[3].rstrip('S'))
    271            reg_mapping = reg[0] + ''.join(['_' for letter in reg[1]]) + reg[3]
    272            reg_enc_fields = re.findall(reg_letter + '+', enc)
    273            if len(reg_enc_fields) == 0:
    274                raise Exception('Tag "{}" missing register field!'.format(tag))
    275            if len(reg_enc_fields) > 1:
    276                raise Exception('Tag "{}" has split register field!'.\
    277                    format(tag))
    278            reg_enc_field = reg_enc_fields[0]
    279            if 2 ** len(reg_enc_field) != reg_num_choices:
    280                raise Exception('Tag "{}" has incorrect register field width!'.\
    281                    format(tag))
    282            print('        DECODE_REG({},{},{})'.\
    283                format(regno, len(reg_enc_field), enc.index(reg_enc_field)),
    284                       file=f)
    285            if reg_type in num_registers and \
    286                reg_num_choices != num_registers[reg_type]:
    287                print('        DECODE_MAPPED_REG({},{})'.\
    288                    format(regno, reg_mapping), file=f)
    289            regno += 1
    290        def implicit_register_key(reg):
    291            return implicit_registers[reg]
    292        for reg in sorted(
    293            set([r for r in (iset.iset[tag]['rregs'].split(',') + \
    294                iset.iset[tag]['wregs'].split(',')) \
    295                    if r in implicit_registers]), key=implicit_register_key):
    296            print('        DECODE_IMPL_REG({},{})'.\
    297                format(regno, implicit_registers[reg]), file=f)
    298            regno += 1
    299        if imms and imms[0][0].isupper():
    300            imms = reversed(imms)
    301        for imm in imms:
    302            if imm[0].isupper():
    303                immno = 1
    304            else:
    305                immno = 0
    306            imm_type = imm[0]
    307            imm_width = int(imm[1])
    308            imm_shift = imm[2]
    309            if imm_shift:
    310                imm_shift = int(imm_shift)
    311            else:
    312                imm_shift = 0
    313            if imm_type.islower():
    314                imm_letter = 'i'
    315            else:
    316                imm_letter = 'I'
    317            remainder = imm_width
    318            for m in reversed(list(re.finditer(imm_letter + '+', enc))):
    319                remainder -= m.end() - m.start()
    320                print('        DECODE_IMM({},{},{},{})'.\
    321                    format(immno, m.end() - m.start(), m.start(), remainder),
    322                        file=f)
    323            if remainder != 0:
    324                if imm[2]:
    325                    imm[2] = ':' + imm[2]
    326                raise Exception('Tag "{}" has an incorrect number of ' + \
    327                    'encoding bits for immediate "{}"'.\
    328                    format(tag, ''.join(imm)))
    329            if imm_type.lower() in 'sr':
    330                print('        DECODE_IMM_SXT({},{})'.\
    331                    format(immno, imm_width), file=f)
    332            if imm_type.lower() == 'n':
    333                print('        DECODE_IMM_NEG({},{})'.\
    334                    format(immno, imm_width), file=f)
    335            if imm_shift:
    336                print('        DECODE_IMM_SHIFT({},{})'.\
    337                    format(immno, imm_shift), file=f)
    338        print(')', file=f)
    339
    340if __name__ == '__main__':
    341    with open(sys.argv[1], 'w') as f:
    342        print_tree(f, dectree_normal)
    343        print_tree(f, dectree_16bit)
    344        if subinsn_groupings:
    345            print_tree(f, dectree_subinsn_groupings)
    346        for (name, dectree_subinsn) in sorted(dectree_subinsns.items()):
    347            print_tree(f, dectree_subinsn)
    348        for (name, dectree_ext) in sorted(dectree_extensions.items()):
    349            print_tree(f, dectree_ext)
    350        print_match_info(f)
    351        print_op_info(f)