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 "$(command -v cc)" ]; then
10	echo "failed: no compiler, install gcc"
11	exit 2
12fi
13
14# skip the test if the hardware doesn't support branch stack sampling
15# and if the architecture doesn't support filter types: any,save_type,u
16if ! perf record -o- --no-buildid --branch-filter any,save_type,u -- true > /dev/null 2>&1 ; then
17	echo "skip: system doesn't support filter types: any,save_type,u"
18	exit 2
19fi
20
21TMPDIR=$(mktemp -d /tmp/__perf_test.program.XXXXX)
22
23cleanup() {
24	rm -rf $TMPDIR
25}
26
27trap cleanup exit term int
28
29gen_test_program() {
30	# generate test program
31	cat << EOF > $1
32#define BENCH_RUNS 999999
33int cnt;
34void bar(void) {
35}			/* return */
36void foo(void) {
37	bar();		/* call */
38}			/* return */
39void bench(void) {
40  void (*foo_ind)(void) = foo;
41  if ((cnt++) % 3)	/* branch (cond) */
42    foo();		/* call */
43  bar();		/* call */
44  foo_ind();		/* call (ind) */
45}
46int main(void)
47{
48  int cnt = 0;
49  while (1) {
50    if ((cnt++) > BENCH_RUNS)
51      break;
52    bench();		/* call */
53  }			/* branch (uncond) */
54  return 0;
55}
56EOF
57}
58
59test_user_branches() {
60	echo "Testing user branch stack sampling"
61
62	gen_test_program "$TEMPDIR/program.c"
63	cc -fno-inline -g "$TEMPDIR/program.c" -o $TMPDIR/a.out
64
65	perf record -o $TMPDIR/perf.data --branch-filter any,save_type,u -- $TMPDIR/a.out > /dev/null 2>&1
66	perf script -i $TMPDIR/perf.data --fields brstacksym | xargs -n1 > $TMPDIR/perf.script
67
68	# example of branch entries:
69	# 	foo+0x14/bar+0x40/P/-/-/0/CALL
70
71	set -x
72	egrep -m1 "^bench\+[^ ]*/foo\+[^ ]*/IND_CALL$"	$TMPDIR/perf.script
73	egrep -m1 "^foo\+[^ ]*/bar\+[^ ]*/CALL$"	$TMPDIR/perf.script
74	egrep -m1 "^bench\+[^ ]*/foo\+[^ ]*/CALL$"	$TMPDIR/perf.script
75	egrep -m1 "^bench\+[^ ]*/bar\+[^ ]*/CALL$"	$TMPDIR/perf.script
76	egrep -m1 "^bar\+[^ ]*/foo\+[^ ]*/RET$"		$TMPDIR/perf.script
77	egrep -m1 "^foo\+[^ ]*/bench\+[^ ]*/RET$"	$TMPDIR/perf.script
78	egrep -m1 "^bench\+[^ ]*/bench\+[^ ]*/COND$"	$TMPDIR/perf.script
79	egrep -m1 "^main\+[^ ]*/main\+[^ ]*/UNCOND$"	$TMPDIR/perf.script
80	set +x
81
82	# some branch types are still not being tested:
83	# IND COND_CALL COND_RET SYSCALL SYSRET IRQ SERROR NO_TX
84}
85
86# first argument <arg0> is the argument passed to "--branch-stack <arg0>,save_type,u"
87# second argument are the expected branch types for the given filter
88test_filter() {
89	local filter=$1
90	local expect=$2
91
92	echo "Testing branch stack filtering permutation ($filter,$expect)"
93
94	gen_test_program "$TEMPDIR/program.c"
95	cc -fno-inline -g "$TEMPDIR/program.c" -o $TMPDIR/a.out
96
97	perf record -o $TMPDIR/perf.data --branch-filter $filter,save_type,u -- $TMPDIR/a.out > /dev/null 2>&1
98	perf script -i $TMPDIR/perf.data --fields brstack | xargs -n1 > $TMPDIR/perf.script
99
100	# fail if we find any branch type that doesn't match any of the expected ones
101	# also consider UNKNOWN branch types (-)
102	if egrep -vm1 "^[^ ]*/($expect|-|( *))$" $TMPDIR/perf.script; then
103		return 1
104	fi
105}
106
107set -e
108
109test_user_branches
110
111test_filter "any_call"	"CALL|IND_CALL|COND_CALL|SYSCALL|IRQ"
112test_filter "call"	"CALL|SYSCALL"
113test_filter "cond"	"COND"
114test_filter "any_ret"	"RET|COND_RET|SYSRET|ERET"
115
116test_filter "call,cond"		"CALL|SYSCALL|COND"
117test_filter "any_call,cond"		"CALL|IND_CALL|COND_CALL|IRQ|SYSCALL|COND"
118test_filter "cond,any_call,any_ret"	"COND|CALL|IND_CALL|COND_CALL|SYSCALL|IRQ|RET|COND_RET|SYSRET|ERET"
119