blob: a949e72a6f202b6f25f890b088810078a2190616 [file] [log] [blame]
#!/usr/bin/env python3
#
# Copyright 2019 The Hafnium Authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Check ELF file for assembly-level regressions.
Objdumps the given ELF file and detects known assembly patterns, checking for
regressions on bugs such as CPU erratas. Throws an exception if a broken pattern
is detected.
"""
import argparse
import os
import re
import subprocess
import sys
HF_ROOT = os.path.dirname(os.path.dirname(os.path.dirname(__file__)))
CLANG_ROOT = os.path.join(HF_ROOT, "prebuilts", "linux-x64", "clang")
OBJDUMP = os.path.join(CLANG_ROOT, "bin", "llvm-objdump")
NM = os.path.join(CLANG_ROOT, "bin", "llvm-nm")
def check_eret_speculation_barrier(args):
"""
Some ARM64 CPUs speculatively execute instructions after ERET.
Check that every ERET is followed by DSB NSH and ISB.
"""
objdump_stdout = subprocess\
.check_output([ OBJDUMP, "-d", args.input_elf ])\
.decode("utf-8")\
.splitlines()
found_eret = False
STATE_DEFAULT = 1
STATE_EXPECT_DSB_NSH = 2
STATE_EXPECT_ISB = 3
REGEX_ERET = re.compile(r"^\s*[0-9a-f]+:\s*e0 03 9f d6\s+eret$")
REGEX_DSB_NSH = re.compile(r"^\s*[0-9a-f]+:\s*9f 37 03 d5\s*dsb\s+nsh$")
REGEX_ISB = re.compile(r"^\s*[0-9a-f]+:\s*df 3f 03 d5\s+isb$")
state = STATE_DEFAULT
for line in objdump_stdout:
if state == STATE_DEFAULT:
if re.match(REGEX_ERET, line):
found_eret = True
state = STATE_EXPECT_DSB_NSH
elif state == STATE_EXPECT_DSB_NSH:
if re.match(REGEX_DSB_NSH, line):
state = STATE_EXPECT_ISB
else:
raise Exception("ERET not followed by DSB NSH")
elif state == STATE_EXPECT_ISB:
if re.match(REGEX_ISB, line):
state = STATE_DEFAULT
else:
raise Exception("ERET not followed by ISB")
# Ensure that at least one instance was found, otherwise the regexes are
# probably wrong.
if not found_eret:
raise Exception("Could not find any ERET instructions")
def check_max_image_size(args):
"""
Check that the ELF's effective image size does not exceed maximum
allowed image size, if specified in command-line arguments.
"""
if args.max_image_size <= 0:
return
nm_stdout = subprocess\
.check_output([ NM, args.input_elf ])\
.decode("utf-8")\
.splitlines()
COLUMN_COUNT = 3
COLUMN_IDX_VALUE = 0
COLUMN_IDX_TYPE = 1
COLUMN_IDX_NAME = 2
image_size = None
for line in nm_stdout:
line = line.split()
if len(line) != COLUMN_COUNT:
raise Exception(
"Unexpected number of columns in NM output")
if line[COLUMN_IDX_NAME] == "image_size":
if line[COLUMN_IDX_TYPE] != "A":
raise Exception(
"Unexpected type of image_size symbol")
image_size = int(line[COLUMN_IDX_VALUE], 16)
break
if image_size is None:
raise Exception("Could not find value of image_size symbol")
elif image_size > args.max_image_size:
raise Exception(
"Image size exceeds maximum allowed image size " +
"({}B > {}B)".format(image_size, args.max_image_size))
def Main():
parser = argparse.ArgumentParser()
parser.add_argument("input_elf",
help="ELF file to analyze")
parser.add_argument("stamp_file",
help="file to be touched if successful")
parser.add_argument("--max-image-size",
required=False, type=int, default=0,
help="maximum allowed image size in bytes")
args = parser.parse_args()
check_eret_speculation_barrier(args)
check_max_image_size(args)
# Touch `stamp_file`.
with open(args.stamp_file, "w"):
pass
return 0
if __name__ == "__main__":
sys.exit(Main())