#!/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,uif ! 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 2fi skip_test_missing_symbol brstack_bench err=0TMPDIR=$(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	local ret=1	for loops in 1000 10000 100000; do		err=0		perf record -o $TMPDIR/perf.data --branch-filter any,save_type,u,k -- \			perf test -w traploop $loops > "$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			ret=0			break		fi	done 	if [ $ret -eq 0 ]; then		echo "Testing trap & eret branches [Passed]"		err=$start_err	else		echo "Testing trap & eret branches [Failed]"		err=1	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	local ret=1	for loops in 1000 10000 100000; do		err=0		perf record -o $TMPDIR/perf.data --branch-filter any,k -- \			perf bench syscall basic --loop $loops > "$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			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			err=1		fi		if [ $err -eq 0 ]; then			ret=0			break		fi	done 	if [ $ret -eq 0 ]; then		echo "Testing kernel branch sampling [Passed]"		err=$start_err	else		echo "Testing kernel branch sampling [Failed]"		err=1	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 filtertest_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	local ret=1	for loops in 8000 30000 100000; do		err=0		perf record -o $TMPDIR/perf.data --branch-filter \			any_call,save_type,u,k -c 10007 -- \			perf bench syscall basic --loop $loops  > "$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			ret=0			break		fi	done 	if [ $ret -eq 0 ]; then		echo "Testing syscalls [Passed]"		err=$start_err	else		echo "Testing syscalls [Failed]"		err=1	fi}set -e test_user_branchestest_syscalltest_kernel_branchestest_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" cleanupexit $err