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| 1 | +#!/usr/bin/env python3 |
| 2 | + |
| 3 | +# Copyright (c) Salil Mittal |
| 4 | +# SPDX-License-Identifier: BSD-3-Clause-Clear |
| 5 | + |
| 6 | +import re |
| 7 | +import os |
| 8 | +import argparse |
| 9 | +import yaml |
| 10 | +import sys |
| 11 | + |
| 12 | +# Add path to import generator.py |
| 13 | +parent_dir = f"{os.path.dirname(__file__)}/../../../backends/generators" |
| 14 | +sys.path.append(parent_dir) |
| 15 | + |
| 16 | +from generator import load_csrs |
| 17 | + |
| 18 | +from capstone import Cs, CS_ARCH_RISCV, CS_MODE_32 |
| 19 | + |
| 20 | + |
| 21 | +# Parse CSRs from the switch case file |
| 22 | +def parse_cases(file_path): |
| 23 | + csrs = set() |
| 24 | + with open(file_path, encoding="utf-8") as f: |
| 25 | + case_addr = None |
| 26 | + for line in f: |
| 27 | + m = re.match(r"\s*case\s+(0x[0-9a-fA-F]+):", line) |
| 28 | + if m: |
| 29 | + case_addr = int(m.group(1), 0) # convert to int |
| 30 | + continue |
| 31 | + if case_addr: |
| 32 | + n = re.match(r'\s*return\s+"([^"]+)";', line) |
| 33 | + if n: |
| 34 | + csr_name = n.group(1) |
| 35 | + csrs.add((csr_name, case_addr)) |
| 36 | + case_addr = None |
| 37 | + return csrs |
| 38 | + |
| 39 | + |
| 40 | +# Retrieve CSRs present in the Capstone package |
| 41 | +# Adds (CSR name / pseudo-instruction, corresponding address) to result set |
| 42 | +def get_capstone_csrs(): |
| 43 | + csrs = set() |
| 44 | + |
| 45 | + md = Cs(CS_ARCH_RISCV, CS_MODE_32) |
| 46 | + for CSR in range(2**12 - 1): |
| 47 | + csrr_hex = f"{CSR:03x}020f3" |
| 48 | + |
| 49 | + # byte swap |
| 50 | + csrr = ( |
| 51 | + csrr_hex[6] |
| 52 | + + csrr_hex[7] |
| 53 | + + csrr_hex[4] |
| 54 | + + csrr_hex[5] |
| 55 | + + csrr_hex[2] |
| 56 | + + csrr_hex[3] |
| 57 | + + csrr_hex[0] |
| 58 | + + csrr_hex[1] |
| 59 | + ) |
| 60 | + csrr_bytes = bytes.fromhex(csrr) |
| 61 | + |
| 62 | + for i in md.disasm(csrr_bytes, 0x1000): |
| 63 | + # Case 1: CSRs having pseudo-instructions |
| 64 | + # Example: rdinstreth ra |
| 65 | + if i.mnemonic != "csrr": |
| 66 | + csrs.add((i.mnemonic, CSR)) |
| 67 | + continue |
| 68 | + |
| 69 | + # Case 2: named CSR operand |
| 70 | + # Example: csrr ra, sstatus |
| 71 | + csr_name_split = i.op_str.split(",") |
| 72 | + if len(csr_name_split) == 2: |
| 73 | + csr_name = csr_name_split[1].strip() |
| 74 | + if not csr_name.isnumeric(): |
| 75 | + csrs.add((csr_name, CSR)) |
| 76 | + return csrs |
| 77 | + |
| 78 | + |
| 79 | +# Extract CSR address from pseudo-instructions which are in the form: |
| 80 | +# xs1 == 0 && csr == <addr> |
| 81 | +# Returns the CSR address if the condition is in the above format else None |
| 82 | +def extract_csr_addr(cond): |
| 83 | + parts = cond.split("&&") |
| 84 | + if len(parts) != 2: |
| 85 | + return None |
| 86 | + |
| 87 | + parts = [p.strip() for p in parts] |
| 88 | + |
| 89 | + xs1_valid = False |
| 90 | + csr_addr = None |
| 91 | + |
| 92 | + for p in parts: |
| 93 | + if "==" not in p: |
| 94 | + return None |
| 95 | + |
| 96 | + # split lhs and rhs in equality |
| 97 | + left, right = (x.strip() for x in p.split("==", 1)) |
| 98 | + |
| 99 | + if left == "xs1": |
| 100 | + if right != "0": |
| 101 | + return None |
| 102 | + xs1_valid = True |
| 103 | + continue |
| 104 | + |
| 105 | + if left == "csr": |
| 106 | + try: |
| 107 | + csr_addr = int(right, 0) # parse both dec and hex addreses |
| 108 | + except ValueError: |
| 109 | + return None |
| 110 | + continue |
| 111 | + |
| 112 | + # unknown left-hand identifier |
| 113 | + return None |
| 114 | + |
| 115 | + if not xs1_valid or csr_addr is None: |
| 116 | + return None |
| 117 | + |
| 118 | + return csr_addr |
| 119 | + |
| 120 | + |
| 121 | +# Get pseudo-instructions for `csrrs` to read specific CSRs |
| 122 | +def get_pseudo_instr(): |
| 123 | + csrrs_path = ( |
| 124 | + f"{os.path.dirname(__file__)}/../../../spec/std/isa/inst/Zicsr/csrrs.yaml" |
| 125 | + ) |
| 126 | + |
| 127 | + with open(csrrs_path, encoding="utf-8") as f: |
| 128 | + data = yaml.safe_load(f) |
| 129 | + pseudo_instructions = data["pseudoinstructions"] |
| 130 | + res = set() |
| 131 | + |
| 132 | + for d in pseudo_instructions: |
| 133 | + addr = extract_csr_addr(d["when"]) |
| 134 | + if addr != None: |
| 135 | + res.add((addr, d["to"])) |
| 136 | + return res |
| 137 | + |
| 138 | + return None |
| 139 | + |
| 140 | + |
| 141 | +def get_pseudo_instr_mapping(): |
| 142 | + csr_list = load_csrs( |
| 143 | + f"{os.path.dirname(__file__)}/../../../spec/std/isa/csr/", |
| 144 | + ["Zicntr", "F"], |
| 145 | + False, |
| 146 | + "BOTH", |
| 147 | + ) |
| 148 | + pseudo_instrs = get_pseudo_instr() |
| 149 | + pseudo_instr_to_csr = {} |
| 150 | + |
| 151 | + for t in pseudo_instrs: |
| 152 | + addr = t[0] |
| 153 | + pseudo_instr = t[1].split(" ")[0].strip() |
| 154 | + pseudo_instr_to_csr[pseudo_instr] = csr_list[addr].lower() |
| 155 | + |
| 156 | + return pseudo_instr_to_csr |
| 157 | + |
| 158 | + |
| 159 | +UNHANDLED_CASES = [ |
| 160 | + (["dscratch"], "Defined as dscratch0, dscratch1 in UDB"), |
| 161 | + ( |
| 162 | + [ |
| 163 | + "utvec", |
| 164 | + "sedeleg", |
| 165 | + "uip", |
| 166 | + "uepc", |
| 167 | + "ustatus", |
| 168 | + "ucause", |
| 169 | + "sideleg", |
| 170 | + "uie", |
| 171 | + "utval", |
| 172 | + "uscratch", |
| 173 | + ], |
| 174 | + "Part of removed N extension", |
| 175 | + ), |
| 176 | + (["pmpaddr13", "pmpaddr14"], "Address error in capstone 5.0.6 package release"), |
| 177 | +] |
| 178 | + |
| 179 | + |
| 180 | +def main(): |
| 181 | + parser = argparse.ArgumentParser( |
| 182 | + description="Compare CSR switch cases in two C files." |
| 183 | + ) |
| 184 | + parser.add_argument( |
| 185 | + "--csr_switch", |
| 186 | + help="Path to C file containing CSR switch case", |
| 187 | + default=f"{os.path.dirname(__file__)}/../../../gen/capstone/csr_switch.c", |
| 188 | + ) |
| 189 | + args = parser.parse_args() |
| 190 | + |
| 191 | + # build unhandled cases dict |
| 192 | + unhandled_cases_dict = {} |
| 193 | + for t in UNHANDLED_CASES: |
| 194 | + for csr in t[0]: |
| 195 | + unhandled_cases_dict[csr] = t[1] |
| 196 | + |
| 197 | + pseudo_instr_to_csr = get_pseudo_instr_mapping() |
| 198 | + |
| 199 | + cases_gen = parse_cases(args.csr_switch) # cases generated using Capstone generator |
| 200 | + capstone_csrs = get_capstone_csrs() |
| 201 | + diff = capstone_csrs - cases_gen |
| 202 | + |
| 203 | + # remove pseudo-instruction cases present in cases_gen |
| 204 | + diff = { |
| 205 | + t |
| 206 | + for t in diff |
| 207 | + if not ( |
| 208 | + t[0] in pseudo_instr_to_csr |
| 209 | + and (pseudo_instr_to_csr[t[0]], t[1]) in cases_gen |
| 210 | + ) |
| 211 | + } |
| 212 | + |
| 213 | + def is_unhandled_case(t): |
| 214 | + if t[0] in unhandled_cases_dict: |
| 215 | + print(f"Ignoring case - {t[0]}. Reason: {unhandled_cases_dict[t[0]]}") |
| 216 | + return True |
| 217 | + else: |
| 218 | + return False |
| 219 | + |
| 220 | + # remove diff cases which are unhandled |
| 221 | + diff = {t for t in diff if not is_unhandled_case(t)} |
| 222 | + |
| 223 | + if len(diff) == 0: |
| 224 | + sys.exit(0) # pass |
| 225 | + else: |
| 226 | + print("CSRs missing in switch statement:", diff) |
| 227 | + sys.exit(1) # fail |
| 228 | + |
| 229 | + |
| 230 | +if __name__ == "__main__": |
| 231 | + main() |
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