test_brstack.sh

  1#!/bin/bash
  2# Check branch stack sampling
  3
  4# SPDX-License-Identifier: GPL-2.0
  5# German Gomez <german.gomez@arm.com>, 2022
  6
  7shelldir=$(dirname "$0")
  8# shellcheck source=lib/perf_has_symbol.sh
  9. "${shelldir}"/lib/perf_has_symbol.sh
 10
 11# skip the test if the hardware doesn't support branch stack sampling
 12# and if the architecture doesn't support filter types: any,save_type,u
 13if ! perf record -o- --no-buildid --branch-filter any,save_type,u -- true > /dev/null 2>&1 ; then
 14	echo "skip: system doesn't support filter types: any,save_type,u"
 15	exit 2
 16fi
 17
 18skip_test_missing_symbol brstack_bench
 19
 20err=0
 21TMPDIR=$(mktemp -d /tmp/__perf_test.program.XXXXX)
 22TESTPROG="perf test -w brstack"
 23
 24cleanup() {
 25	rm -rf $TMPDIR
 26	trap - EXIT TERM INT
 27}
 28
 29trap_cleanup() {
 30	set +e
 31	echo "Unexpected signal in ${FUNCNAME[1]}"
 32	cleanup
 33	exit 1
 34}
 35trap trap_cleanup EXIT TERM INT
 36
 37is_arm64() {
 38	[ "$(uname -m)" = "aarch64" ];
 39}
 40
 41check_branches() {
 42	if ! tr -s ' ' '\n' < "$TMPDIR/perf.script" | grep -E -m1 -q "$1"; then
 43		echo "Branches missing $1"
 44		err=1
 45	fi
 46}
 47
 48test_user_branches() {
 49	echo "Testing user branch stack sampling"
 50
 51	perf record -o "$TMPDIR/perf.data" --branch-filter any,save_type,u -- ${TESTPROG} > "$TMPDIR/record.txt" 2>&1
 52	perf script -i "$TMPDIR/perf.data" --fields brstacksym > "$TMPDIR/perf.script"
 53
 54	# example of branch entries:
 55	# 	brstack_foo+0x14/brstack_bar+0x40/P/-/-/0/CALL
 56
 57	expected=(
 58		"^brstack_bench\+[^ ]*/brstack_foo\+[^ ]*/IND_CALL/.*$"
 59		"^brstack_foo\+[^ ]*/brstack_bar\+[^ ]*/CALL/.*$"
 60		"^brstack_bench\+[^ ]*/brstack_foo\+[^ ]*/CALL/.*$"
 61		"^brstack_bench\+[^ ]*/brstack_bar\+[^ ]*/CALL/.*$"
 62		"^brstack_bar\+[^ ]*/brstack_foo\+[^ ]*/RET/.*$"
 63		"^brstack_foo\+[^ ]*/brstack_bench\+[^ ]*/RET/.*$"
 64		"^brstack_bench\+[^ ]*/brstack_bench\+[^ ]*/COND/.*$"
 65		"^brstack\+[^ ]*/brstack\+[^ ]*/UNCOND/.*$"
 66	)
 67	for x in "${expected[@]}"
 68	do
 69		check_branches "$x"
 70	done
 71
 72	# Dump addresses only this time
 73	perf script -i "$TMPDIR/perf.data" --fields brstack | \
 74		tr ' ' '\n' > "$TMPDIR/perf.script"
 75
 76	# There should be no kernel addresses with the u option, in either
 77	# source or target addresses.
 78	if grep -E -m1 "0x[89a-f][0-9a-f]{15}" $TMPDIR/perf.script; then
 79		echo "ERROR: Kernel address found in user mode"
 80		err=1
 81	fi
 82	# some branch types are still not being tested:
 83	# IND COND_CALL COND_RET SYSRET SERROR NO_TX
 84}
 85
 86test_trap_eret_branches() {
 87	echo "Testing trap & eret branches"
 88	if ! is_arm64; then
 89		echo "skip: not arm64"
 90	else
 91		perf record -o $TMPDIR/perf.data --branch-filter any,save_type,u,k -- \
 92			perf test -w traploop 1000
 93		perf script -i $TMPDIR/perf.data --fields brstacksym | \
 94			tr ' ' '\n' > $TMPDIR/perf.script
 95
 96		# BRBINF<n>.TYPE == TRAP are mapped to PERF_BR_IRQ by the BRBE driver
 97		check_branches "^trap_bench\+[^ ]+/[^ ]/IRQ/"
 98		check_branches "^[^ ]+/trap_bench\+[^ ]+/ERET/"
 99	fi
100}
101
102test_kernel_branches() {
103	echo "Testing that k option only includes kernel source addresses"
104
105	if ! perf record --branch-filter any,k -o- -- true > /dev/null; then
106		echo "skip: not enough privileges"
107	else
108		perf record -o $TMPDIR/perf.data --branch-filter any,k -- \
109			perf bench syscall basic --loop 1000
110		perf script -i $TMPDIR/perf.data --fields brstack | \
111			tr ' ' '\n' > $TMPDIR/perf.script
112
113		# Example of branch entries:
114		#       "0xffffffff93bda241/0xffffffff93bda20f/M/-/-/..."
115		# Source addresses come first and target address can be either
116		# userspace or kernel even with k option, as long as the source
117		# is in kernel.
118
119		#Look for source addresses with top bit set
120		if ! grep -E -m1 "^0x[89a-f][0-9a-f]{15}" $TMPDIR/perf.script; then
121			echo "ERROR: Kernel branches missing"
122			err=1
123		fi
124		# Look for no source addresses without top bit set
125		if grep -E -m1 "^0x[0-7][0-9a-f]{0,15}" $TMPDIR/perf.script; then
126			echo "ERROR: User branches found with kernel filter"
127			err=1
128		fi
129	fi
130}
131
132# first argument <arg0> is the argument passed to "--branch-stack <arg0>,save_type,u"
133# second argument are the expected branch types for the given filter
134test_filter() {
135	test_filter_filter=$1
136	test_filter_expect=$2
137
138	echo "Testing branch stack filtering permutation ($test_filter_filter,$test_filter_expect)"
139	perf record -o "$TMPDIR/perf.data" --branch-filter "$test_filter_filter,save_type,u" -- ${TESTPROG}  > "$TMPDIR/record.txt" 2>&1
140	perf script -i "$TMPDIR/perf.data" --fields brstack > "$TMPDIR/perf.script"
141
142	# fail if we find any branch type that doesn't match any of the expected ones
143	# also consider UNKNOWN branch types (-)
144	if [ ! -s "$TMPDIR/perf.script" ]
145	then
146		echo "Empty script output"
147		err=1
148		return
149	fi
150	# Look for lines not matching test_filter_expect ignoring issues caused
151	# by empty output
152	tr -s ' ' '\n' < "$TMPDIR/perf.script" | grep '.' | \
153	  grep -E -vm1 "^[^ ]*/($test_filter_expect|-|( *))/.*$" \
154	  > "$TMPDIR/perf.script-filtered" || true
155	if [ -s "$TMPDIR/perf.script-filtered" ]
156	then
157		echo "Unexpected branch filter in script output"
158		cat "$TMPDIR/perf.script"
159		err=1
160		return
161	fi
162}
163
164test_syscall() {
165	echo "Testing syscalls"
166	# skip if perf doesn't have enough privileges
167	if ! perf record --branch-filter any,k -o- -- true > /dev/null; then
168		echo "skip: not enough privileges"
169	else
170		perf record -o $TMPDIR/perf.data --branch-filter \
171			any_call,save_type,u,k -c 10000 -- \
172			perf bench syscall basic --loop 1000
173		perf script -i $TMPDIR/perf.data --fields brstacksym | \
174			tr ' ' '\n' > $TMPDIR/perf.script
175
176		check_branches "getppid[^ ]*/SYSCALL/"
177	fi
178}
179set -e
180
181test_user_branches
182test_syscall
183test_kernel_branches
184test_trap_eret_branches
185
186any_call="CALL|IND_CALL|COND_CALL|SYSCALL|IRQ"
187
188if is_arm64; then
189	any_call="$any_call|FAULT_DATA|FAULT_INST"
190fi
191
192test_filter "any_call" "$any_call"
193test_filter "call"	"CALL|SYSCALL"
194test_filter "cond"	"COND"
195test_filter "any_ret"	"RET|COND_RET|SYSRET|ERET"
196
197test_filter "call,cond"		"CALL|SYSCALL|COND"
198test_filter "any_call,cond"	    "$any_call|COND"
199test_filter "any_call,cond,any_ret" "$any_call|COND|RET|COND_RET"
200
201cleanup
202exit $err