#!/bin/sh# Check branch stack sampling # SPDX-License-Identifier: GPL-2.0# German Gomez <german.gomez@arm.com>, 2022 # we need a C compiler to build the test programs# so bail if none is foundif ! [ -x "$(command -v cc)" ]; then	echo "failed: no compiler, install gcc"	exit 2fi # skip the test if the hardware doesn't support branch stack sampling# and if the architecture doesn't support filter types: any,save_type,uif ! perf record -o- --no-buildid --branch-filter any,save_type,u -- true > /dev/null 2>&1 ; then	echo "skip: system doesn't support filter types: any,save_type,u"	exit 2fi TMPDIR=$(mktemp -d /tmp/__perf_test.program.XXXXX) cleanup() {	rm -rf $TMPDIR} trap cleanup exit term int gen_test_program() {	# generate test program	cat << EOF > $1#define BENCH_RUNS 999999int cnt;void bar(void) {}			/* return */void foo(void) {	bar();		/* call */}			/* return */void bench(void) {  void (*foo_ind)(void) = foo;  if ((cnt++) % 3)	/* branch (cond) */    foo();		/* call */  bar();		/* call */  foo_ind();		/* call (ind) */}int main(void){  int cnt = 0;  while (1) {    if ((cnt++) > BENCH_RUNS)      break;    bench();		/* call */  }			/* branch (uncond) */  return 0;}EOF} test_user_branches() {	echo "Testing user branch stack sampling" 	gen_test_program "$TEMPDIR/program.c"	cc -fno-inline -g "$TEMPDIR/program.c" -o $TMPDIR/a.out 	perf record -o $TMPDIR/perf.data --branch-filter any,save_type,u -- $TMPDIR/a.out > /dev/null 2>&1	perf script -i $TMPDIR/perf.data --fields brstacksym | xargs -n1 > $TMPDIR/perf.script 	# example of branch entries:	# 	foo+0x14/bar+0x40/P/-/-/0/CALL 	set -x	egrep -m1 "^bench\+[^ ]*/foo\+[^ ]*/IND_CALL$"	$TMPDIR/perf.script	egrep -m1 "^foo\+[^ ]*/bar\+[^ ]*/CALL$"	$TMPDIR/perf.script	egrep -m1 "^bench\+[^ ]*/foo\+[^ ]*/CALL$"	$TMPDIR/perf.script	egrep -m1 "^bench\+[^ ]*/bar\+[^ ]*/CALL$"	$TMPDIR/perf.script	egrep -m1 "^bar\+[^ ]*/foo\+[^ ]*/RET$"		$TMPDIR/perf.script	egrep -m1 "^foo\+[^ ]*/bench\+[^ ]*/RET$"	$TMPDIR/perf.script	egrep -m1 "^bench\+[^ ]*/bench\+[^ ]*/COND$"	$TMPDIR/perf.script	egrep -m1 "^main\+[^ ]*/main\+[^ ]*/UNCOND$"	$TMPDIR/perf.script	set +x 	# some branch types are still not being tested:	# IND COND_CALL COND_RET SYSCALL SYSRET IRQ SERROR NO_TX} # 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() {	local filter=$1	local expect=$2 	echo "Testing branch stack filtering permutation ($filter,$expect)" 	gen_test_program "$TEMPDIR/program.c"	cc -fno-inline -g "$TEMPDIR/program.c" -o $TMPDIR/a.out 	perf record -o $TMPDIR/perf.data --branch-filter $filter,save_type,u -- $TMPDIR/a.out > /dev/null 2>&1	perf script -i $TMPDIR/perf.data --fields brstack | xargs -n1 > $TMPDIR/perf.script 	# fail if we find any branch type that doesn't match any of the expected ones	# also consider UNKNOWN branch types (-)	if egrep -vm1 "^[^ ]*/($expect|-|( *))$" $TMPDIR/perf.script; then		return 1	fi} set -e test_user_branches test_filter "any_call"	"CALL|IND_CALL|COND_CALL|SYSCALL|IRQ"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"		"CALL|IND_CALL|COND_CALL|IRQ|SYSCALL|COND"test_filter "cond,any_call,any_ret"	"COND|CALL|IND_CALL|COND_CALL|SYSCALL|IRQ|RET|COND_RET|SYSRET|ERET"