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|
#!/bin/bash
# Check branch stack sampling
# SPDX-License-Identifier: GPL-2.0
# German Gomez <german.gomez@arm.com>, 2022
shelldir=$(dirname "$0")
# shellcheck source=lib/perf_has_symbol.sh
. "${shelldir}"/lib/perf_has_symbol.sh
# skip the test if the hardware doesn't support branch stack sampling
# and if the architecture doesn't support filter types: any,save_type,u
if ! perf record -o- --no-buildid --branch-filter any,save_type,u -- true > /dev/null 2>&1 ; then
echo "skip: system doesn't support filter types: any,save_type,u"
exit 2
fi
skip_test_missing_symbol brstack_bench
err=0
TMPDIR=$(mktemp -d /tmp/__perf_test.program.XXXXX)
TESTPROG="perf test -w brstack"
cleanup() {
rm -rf $TMPDIR
trap - EXIT TERM INT
}
trap_cleanup() {
set +e
echo "Unexpected signal in ${FUNCNAME[1]}"
cleanup
exit 1
}
trap trap_cleanup EXIT TERM INT
is_arm64() {
[ "$(uname -m)" = "aarch64" ];
}
has_kaslr_bug() {
[ "$(uname -m)" != "aarch64" ];
}
check_branches() {
if ! tr -s ' ' '\n' < "$TMPDIR/perf.script" | grep -E -m1 -q "$1"; then
echo "ERROR: Branches missing $1"
err=1
fi
}
test_user_branches() {
echo "Testing user branch stack sampling"
start_err=$err
err=0
perf record -o "$TMPDIR/perf.data" --branch-filter any,save_type,u -- ${TESTPROG} > "$TMPDIR/record.txt" 2>&1
perf script -i "$TMPDIR/perf.data" --fields brstacksym > "$TMPDIR/perf.script"
# example of branch entries:
# brstack_foo+0x14/brstack_bar+0x40/P/-/-/0/CALL
expected=(
"^brstack_bench\+[^ ]*/brstack_foo\+[^ ]*/IND_CALL/.*$"
"^brstack_foo\+[^ ]*/brstack_bar\+[^ ]*/CALL/.*$"
"^brstack_bench\+[^ ]*/brstack_foo\+[^ ]*/CALL/.*$"
"^brstack_bench\+[^ ]*/brstack_bar\+[^ ]*/CALL/.*$"
"^brstack_bar\+[^ ]*/brstack_foo\+[^ ]*/RET/.*$"
"^brstack_foo\+[^ ]*/brstack_bench\+[^ ]*/RET/.*$"
"^brstack_bench\+[^ ]*/brstack_bench\+[^ ]*/COND/.*$"
"^brstack\+[^ ]*/brstack\+[^ ]*/UNCOND/.*$"
)
for x in "${expected[@]}"
do
check_branches "$x"
done
# Dump addresses only this time
perf script -i "$TMPDIR/perf.data" --fields brstack | \
tr ' ' '\n' > "$TMPDIR/perf.script"
# There should be no kernel addresses in the target with the u option.
local regex="0x[89a-f][0-9a-f]{15}"
if has_kaslr_bug; then
# If the system has a kaslr bug that may leak kernel addresses
# in the source of something like an ERET/SYSRET. Make the regex
# more specific and just check the target address is in user
# code.
regex="^0x[0-9a-f]{0,16}/0x[89a-f][0-9a-f]{15}/"
fi
if grep -q -E -m1 "$regex" $TMPDIR/perf.script; then
echo "Testing user branch stack sampling [Failed kernel address found in user mode]"
err=1
fi
# some branch types are still not being tested:
# IND COND_CALL COND_RET SYSRET SERROR NO_TX
if [ $err -eq 0 ]; then
echo "Testing user branch stack sampling [Passed]"
err=$start_err
else
echo "Testing user branch stack sampling [Failed]"
fi
}
test_trap_eret_branches() {
echo "Testing trap & eret branches"
if ! is_arm64; then
echo "Testing trap & eret branches [Skipped not arm64]"
return
fi
start_err=$err
err=0
perf record -o $TMPDIR/perf.data --branch-filter any,save_type,u,k -- \
perf test -w traploop 1000 > "$TMPDIR/record.txt" 2>&1
perf script -i $TMPDIR/perf.data --fields brstacksym | \
tr ' ' '\n' > $TMPDIR/perf.script
# BRBINF<n>.TYPE == TRAP are mapped to PERF_BR_IRQ by the BRBE driver
check_branches "^trap_bench\+[^ ]+/[^ ]/IRQ/"
check_branches "^[^ ]+/trap_bench\+[^ ]+/ERET/"
if [ $err -eq 0 ]; then
echo "Testing trap & eret branches [Passed]"
err=$start_err
else
echo "Testing trap & eret branches [Failed]"
fi
}
test_kernel_branches() {
echo "Testing kernel branch sampling"
if ! perf record --branch-filter any,k -o- -- true > "$TMPDIR/record.txt" 2>&1; then
echo "Testing that k option [Skipped not enough privileges]"
return
fi
start_err=$err
err=0
perf record -o $TMPDIR/perf.data --branch-filter any,k -- \
perf bench syscall basic --loop 1000 > "$TMPDIR/record.txt" 2>&1
perf script -i $TMPDIR/perf.data --fields brstack | \
tr ' ' '\n' > $TMPDIR/perf.script
# Example of branch entries:
# "0xffffffff93bda241/0xffffffff93bda20f/M/-/-/..."
# Source addresses come first in user or kernel code. Next is the target
# address that must be in the kernel.
# Look for source addresses with top bit set
if ! grep -q -E -m1 "^0x[89a-f][0-9a-f]{15}" $TMPDIR/perf.script; then
echo "Testing kernel branch sampling [Failed kernel branches missing]"
err=1
fi
# Look for no target addresses without top bit set
if grep -q -E -m1 "^0x[0-9a-f]{0,16}/0x[0-7][0-9a-f]{1,15}/" $TMPDIR/perf.script; then
echo "Testing kernel branch sampling [Failed user branches found]"
err=1
fi
if [ $err -eq 0 ]; then
echo "Testing kernel branch sampling [Passed]"
err=$start_err
else
echo "Testing kernel branch sampling [Failed]"
fi
}
# first argument <arg0> is the argument passed to "--branch-stack <arg0>,save_type,u"
# second argument are the expected branch types for the given filter
test_filter() {
test_filter_filter=$1
test_filter_expect=$2
echo "Testing branch stack filtering permutation ($test_filter_filter,$test_filter_expect)"
perf record -o "$TMPDIR/perf.data" --branch-filter "$test_filter_filter,save_type,u" -- \
${TESTPROG} > "$TMPDIR/record.txt" 2>&1
perf script -i "$TMPDIR/perf.data" --fields brstack > "$TMPDIR/perf.script"
# fail if we find any branch type that doesn't match any of the expected ones
# also consider UNKNOWN branch types (-)
if [ ! -s "$TMPDIR/perf.script" ]
then
echo "Testing branch stack filtering [Failed empty script output]"
err=1
return
fi
# Look for lines not matching test_filter_expect ignoring issues caused
# by empty output
tr -s ' ' '\n' < "$TMPDIR/perf.script" | grep '.' | \
grep -E -vm1 "^[^ ]*/($test_filter_expect|-|( *))/.*$" \
> "$TMPDIR/perf.script-filtered" || true
if [ -s "$TMPDIR/perf.script-filtered" ]
then
echo "Testing branch stack filtering [Failed unexpected branch filter]"
cat "$TMPDIR/perf.script"
err=1
return
fi
echo "Testing branch stack filtering [Passed]"
}
test_syscall() {
echo "Testing syscalls"
# skip if perf doesn't have enough privileges
if ! perf record --branch-filter any,k -o- -- true > "$TMPDIR/record.txt" 2>&1; then
echo "Testing syscalls [Skipped: not enough privileges]"
return
fi
start_err=$err
err=0
perf record -o $TMPDIR/perf.data --branch-filter \
any_call,save_type,u,k -c 10007 -- \
perf bench syscall basic --loop 8000 > "$TMPDIR/record.txt" 2>&1
perf script -i $TMPDIR/perf.data --fields brstacksym | \
tr ' ' '\n' > $TMPDIR/perf.script
check_branches "getppid[^ ]*/SYSCALL/"
if [ $err -eq 0 ]; then
echo "Testing syscalls [Passed]"
err=$start_err
else
echo "Testing syscalls [Failed]"
fi
}
set -e
test_user_branches
test_syscall
test_kernel_branches
test_trap_eret_branches
any_call="CALL|IND_CALL|COND_CALL|SYSCALL|IRQ"
if is_arm64; then
any_call="$any_call|FAULT_DATA|FAULT_INST"
fi
test_filter "any_call" "$any_call"
test_filter "call" "CALL|SYSCALL"
test_filter "cond" "COND"
test_filter "any_ret" "RET|COND_RET|SYSRET|ERET"
test_filter "call,cond" "CALL|SYSCALL|COND"
test_filter "any_call,cond" "$any_call|COND"
test_filter "any_call,cond,any_ret" "$any_call|COND|RET|COND_RET"
cleanup
exit $err
|
