1#!/bin/sh
2# Check branch stack sampling
3
4# SPDX-License-Identifier: GPL-2.0
5# German Gomez <german.gomez@arm.com>, 2022
6
7# we need a C compiler to build the test programs
8# so bail if none is found
9if ! [ -x "$(command -v cc)" ]; then
10	echo "failed: no compiler, install gcc"
11	exit 2
12fi
13
14# skip the test if the hardware doesn't support branch stack sampling
15# and if the architecture doesn't support filter types: any,save_type,u
16perf record -b -o- -B --branch-filter any,save_type,u true > /dev/null 2>&1 || exit 2
17
18TMPDIR=$(mktemp -d /tmp/__perf_test.program.XXXXX)
19
20cleanup() {
21	rm -rf $TMPDIR
22}
23
24trap cleanup exit term int
25
26gen_test_program() {
27	# generate test program
28	cat << EOF > $1
29#define BENCH_RUNS 999999
30int cnt;
31void bar(void) {
32}			/* return */
33void foo(void) {
34	bar();		/* call */
35}			/* return */
36void bench(void) {
37  void (*foo_ind)(void) = foo;
38  if ((cnt++) % 3)	/* branch (cond) */
39    foo();		/* call */
40  bar();		/* call */
41  foo_ind();		/* call (ind) */
42}
43int main(void)
44{
45  int cnt = 0;
46  while (1) {
47    if ((cnt++) > BENCH_RUNS)
48      break;
49    bench();		/* call */
50  }			/* branch (uncond) */
51  return 0;
52}
53EOF
54}
55
56test_user_branches() {
57	echo "Testing user branch stack sampling"
58
59	gen_test_program "$TEMPDIR/program.c"
60	cc -fno-inline -g "$TEMPDIR/program.c" -o $TMPDIR/a.out
61
62	perf record -o $TMPDIR/perf.data --branch-filter any,save_type,u -- $TMPDIR/a.out > /dev/null 2>&1
63	perf script -i $TMPDIR/perf.data --fields brstacksym | xargs -n1 > $TMPDIR/perf.script
64
65	# example of branch entries:
66	# 	foo+0x14/bar+0x40/P/-/-/0/CALL
67
68	set -x
69	egrep -m1 "^bench\+[^ ]*/foo\+[^ ]*/IND_CALL$"	$TMPDIR/perf.script
70	egrep -m1 "^foo\+[^ ]*/bar\+[^ ]*/CALL$"	$TMPDIR/perf.script
71	egrep -m1 "^bench\+[^ ]*/foo\+[^ ]*/CALL$"	$TMPDIR/perf.script
72	egrep -m1 "^bench\+[^ ]*/bar\+[^ ]*/CALL$"	$TMPDIR/perf.script
73	egrep -m1 "^bar\+[^ ]*/foo\+[^ ]*/RET$"		$TMPDIR/perf.script
74	egrep -m1 "^foo\+[^ ]*/bench\+[^ ]*/RET$"	$TMPDIR/perf.script
75	egrep -m1 "^bench\+[^ ]*/bench\+[^ ]*/COND$"	$TMPDIR/perf.script
76	egrep -m1 "^main\+[^ ]*/main\+[^ ]*/UNCOND$"	$TMPDIR/perf.script
77	set +x
78
79	# some branch types are still not being tested:
80	# IND COND_CALL COND_RET SYSCALL SYSRET IRQ SERROR NO_TX
81}
82
83# first argument <arg0> is the argument passed to "--branch-stack <arg0>,save_type,u"
84# second argument are the expected branch types for the given filter
85test_filter() {
86	local filter=$1
87	local expect=$2
88
89	echo "Testing branch stack filtering permutation ($filter,$expect)"
90
91	gen_test_program "$TEMPDIR/program.c"
92	cc -fno-inline -g "$TEMPDIR/program.c" -o $TMPDIR/a.out
93
94	perf record -o $TMPDIR/perf.data --branch-filter $filter,save_type,u -- $TMPDIR/a.out > /dev/null 2>&1
95	perf script -i $TMPDIR/perf.data --fields brstack | xargs -n1 > $TMPDIR/perf.script
96
97	# fail if we find any branch type that doesn't match any of the expected ones
98	# also consider UNKNOWN branch types (-)
99	if egrep -vm1 "^[^ ]*/($expect|-|( *))$" $TMPDIR/perf.script; then
100		return 1
101	fi
102}
103
104set -e
105
106test_user_branches
107
108test_filter "any_call"	"CALL|IND_CALL|COND_CALL|SYSCALL|IRQ"
109test_filter "call"	"CALL|SYSCALL"
110test_filter "cond"	"COND"
111test_filter "any_ret"	"RET|COND_RET|SYSRET|ERET"
112
113test_filter "call,cond"		"CALL|SYSCALL|COND"
114test_filter "any_call,cond"		"CALL|IND_CALL|COND_CALL|IRQ|SYSCALL|COND"
115test_filter "cond,any_call,any_ret"	"COND|CALL|IND_CALL|COND_CALL|SYSCALL|IRQ|RET|COND_RET|SYSRET|ERET"
116